diff --git a/vendor/go.etcd.io/etcd/server/v3/LICENSE b/vendor/go.etcd.io/etcd/server/v3/LICENSE
new file mode 100644
index 0000000..d645695
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/LICENSE
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
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+      and distribution as defined by Sections 1 through 9 of this document.
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+      outstanding shares, or (iii) beneficial ownership of such entity.
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+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
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+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
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+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
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+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
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+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
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+      Contributor provides its Contributions) on an "AS IS" BASIS,
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+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
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+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/vendor/go.etcd.io/etcd/server/v3/auth/doc.go b/vendor/go.etcd.io/etcd/server/v3/auth/doc.go
new file mode 100644
index 0000000..72741a1
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/auth/doc.go
@@ -0,0 +1,16 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package auth provides client role authentication for accessing keys in etcd.
+package auth
diff --git a/vendor/go.etcd.io/etcd/server/v3/auth/jwt.go b/vendor/go.etcd.io/etcd/server/v3/auth/jwt.go
new file mode 100644
index 0000000..e6aad18
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/auth/jwt.go
@@ -0,0 +1,177 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package auth
+
+import (
+	"context"
+	"crypto/ecdsa"
+	"crypto/ed25519"
+	"crypto/rsa"
+	"errors"
+	"time"
+
+	"github.com/golang-jwt/jwt/v5"
+	"go.uber.org/zap"
+)
+
+type tokenJWT struct {
+	lg         *zap.Logger
+	signMethod jwt.SigningMethod
+	key        any
+	ttl        time.Duration
+	verifyOnly bool
+}
+
+func (t *tokenJWT) enable()                         {}
+func (t *tokenJWT) disable()                        {}
+func (t *tokenJWT) invalidateUser(string)           {}
+func (t *tokenJWT) genTokenPrefix() (string, error) { return "", nil }
+
+func (t *tokenJWT) info(ctx context.Context, token string, rev uint64) (*AuthInfo, bool) {
+	// rev isn't used in JWT, it is only used in simple token
+	var (
+		username string
+		revision float64
+	)
+
+	parsed, err := jwt.Parse(token, func(token *jwt.Token) (any, error) {
+		if token.Method.Alg() != t.signMethod.Alg() {
+			return nil, errors.New("invalid signing method")
+		}
+		switch k := t.key.(type) {
+		case *rsa.PrivateKey:
+			return &k.PublicKey, nil
+		case *ecdsa.PrivateKey:
+			return &k.PublicKey, nil
+		case ed25519.PrivateKey:
+			return k.Public(), nil
+		default:
+			return t.key, nil
+		}
+	})
+	if err != nil {
+		t.lg.Warn(
+			"failed to parse a JWT token",
+			zap.Error(err),
+		)
+		return nil, false
+	}
+
+	claims, ok := parsed.Claims.(jwt.MapClaims)
+	if !parsed.Valid || !ok {
+		t.lg.Warn("failed to obtain claims from a JWT token")
+		return nil, false
+	}
+
+	username, ok = claims["username"].(string)
+	if !ok {
+		t.lg.Warn("failed to obtain user claims from jwt token")
+		return nil, false
+	}
+
+	revision, ok = claims["revision"].(float64)
+	if !ok {
+		t.lg.Warn("failed to obtain revision claims from jwt token")
+		return nil, false
+	}
+
+	return &AuthInfo{Username: username, Revision: uint64(revision)}, true
+}
+
+func (t *tokenJWT) assign(ctx context.Context, username string, revision uint64) (string, error) {
+	if t.verifyOnly {
+		return "", ErrVerifyOnly
+	}
+
+	// Future work: let a jwt token include permission information would be useful for
+	// permission checking in proxy side.
+	tk := jwt.NewWithClaims(t.signMethod,
+		jwt.MapClaims{
+			"username": username,
+			"revision": revision,
+			"exp":      time.Now().Add(t.ttl).Unix(),
+		})
+
+	token, err := tk.SignedString(t.key)
+	if err != nil {
+		t.lg.Debug(
+			"failed to sign a JWT token",
+			zap.String("user-name", username),
+			zap.Uint64("revision", revision),
+			zap.Error(err),
+		)
+		return "", err
+	}
+
+	t.lg.Debug(
+		"created/assigned a new JWT token",
+		zap.String("user-name", username),
+		zap.Uint64("revision", revision),
+		zap.String("token", token),
+	)
+	return token, err
+}
+
+func newTokenProviderJWT(lg *zap.Logger, optMap map[string]string) (*tokenJWT, error) {
+	if lg == nil {
+		lg = zap.NewNop()
+	}
+	var err error
+	var opts jwtOptions
+	err = opts.ParseWithDefaults(optMap)
+	if err != nil {
+		lg.Error("problem loading JWT options", zap.Error(err))
+		return nil, ErrInvalidAuthOpts
+	}
+
+	keys := make([]string, 0, len(optMap))
+	for k := range optMap {
+		if !knownOptions[k] {
+			keys = append(keys, k)
+		}
+	}
+	if len(keys) > 0 {
+		lg.Warn("unknown JWT options", zap.Strings("keys", keys))
+	}
+
+	key, err := opts.Key()
+	if err != nil {
+		return nil, err
+	}
+
+	t := &tokenJWT{
+		lg:         lg,
+		ttl:        opts.TTL,
+		signMethod: opts.SignMethod,
+		key:        key,
+	}
+
+	switch t.signMethod.(type) {
+	case *jwt.SigningMethodECDSA:
+		if _, ok := t.key.(*ecdsa.PublicKey); ok {
+			t.verifyOnly = true
+		}
+	case *jwt.SigningMethodEd25519:
+		if _, ok := t.key.(ed25519.PublicKey); ok {
+			t.verifyOnly = true
+		}
+	case *jwt.SigningMethodRSA, *jwt.SigningMethodRSAPSS:
+		if _, ok := t.key.(*rsa.PublicKey); ok {
+			t.verifyOnly = true
+		}
+	}
+
+	return t, nil
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/auth/metrics.go b/vendor/go.etcd.io/etcd/server/v3/auth/metrics.go
new file mode 100644
index 0000000..8bf9470
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/auth/metrics.go
@@ -0,0 +1,44 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package auth
+
+import (
+	"sync"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+var (
+	currentAuthRevision = prometheus.NewGaugeFunc(
+		prometheus.GaugeOpts{
+			Namespace: "etcd_debugging",
+			Subsystem: "auth",
+			Name:      "revision",
+			Help:      "The current revision of auth store.",
+		},
+		func() float64 {
+			reportCurrentAuthRevMu.RLock()
+			defer reportCurrentAuthRevMu.RUnlock()
+			return reportCurrentAuthRev()
+		},
+	)
+	// overridden by auth store initialization
+	reportCurrentAuthRevMu sync.RWMutex
+	reportCurrentAuthRev   = func() float64 { return 0 }
+)
+
+func init() {
+	prometheus.MustRegister(currentAuthRevision)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/auth/nop.go b/vendor/go.etcd.io/etcd/server/v3/auth/nop.go
new file mode 100644
index 0000000..8ba3f8c
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/auth/nop.go
@@ -0,0 +1,37 @@
+// Copyright 2018 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package auth
+
+import (
+	"context"
+)
+
+type tokenNop struct{}
+
+func (t *tokenNop) enable()                         {}
+func (t *tokenNop) disable()                        {}
+func (t *tokenNop) invalidateUser(string)           {}
+func (t *tokenNop) genTokenPrefix() (string, error) { return "", nil }
+func (t *tokenNop) info(ctx context.Context, token string, rev uint64) (*AuthInfo, bool) {
+	return nil, false
+}
+
+func (t *tokenNop) assign(ctx context.Context, username string, revision uint64) (string, error) {
+	return "", ErrAuthFailed
+}
+
+func newTokenProviderNop() (*tokenNop, error) {
+	return &tokenNop{}, nil
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/auth/options.go b/vendor/go.etcd.io/etcd/server/v3/auth/options.go
new file mode 100644
index 0000000..fa9db20
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/auth/options.go
@@ -0,0 +1,235 @@
+// Copyright 2018 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package auth
+
+import (
+	"crypto"
+	"crypto/ecdsa"
+	"crypto/ed25519"
+	"crypto/rsa"
+	"fmt"
+	"os"
+	"time"
+
+	"github.com/golang-jwt/jwt/v5"
+)
+
+const (
+	optSignMethod = "sign-method"
+	optPublicKey  = "pub-key"
+	optPrivateKey = "priv-key"
+	optTTL        = "ttl"
+)
+
+var knownOptions = map[string]bool{
+	optSignMethod: true,
+	optPublicKey:  true,
+	optPrivateKey: true,
+	optTTL:        true,
+}
+
+// DefaultTTL will be used when a 'ttl' is not specified
+var DefaultTTL = 5 * time.Minute
+
+type jwtOptions struct {
+	SignMethod jwt.SigningMethod
+	PublicKey  []byte
+	PrivateKey []byte
+	TTL        time.Duration
+}
+
+// ParseWithDefaults will load options from the specified map or set defaults where appropriate
+func (opts *jwtOptions) ParseWithDefaults(optMap map[string]string) error {
+	if opts.TTL == 0 && optMap[optTTL] == "" {
+		opts.TTL = DefaultTTL
+	}
+
+	return opts.Parse(optMap)
+}
+
+// Parse will load options from the specified map
+func (opts *jwtOptions) Parse(optMap map[string]string) error {
+	var err error
+	if ttl := optMap[optTTL]; ttl != "" {
+		opts.TTL, err = time.ParseDuration(ttl)
+		if err != nil {
+			return err
+		}
+	}
+
+	if file := optMap[optPublicKey]; file != "" {
+		opts.PublicKey, err = os.ReadFile(file)
+		if err != nil {
+			return err
+		}
+	}
+
+	if file := optMap[optPrivateKey]; file != "" {
+		opts.PrivateKey, err = os.ReadFile(file)
+		if err != nil {
+			return err
+		}
+	}
+
+	// signing method is a required field
+	method := optMap[optSignMethod]
+	opts.SignMethod = jwt.GetSigningMethod(method)
+	if opts.SignMethod == nil {
+		return ErrInvalidAuthMethod
+	}
+
+	return nil
+}
+
+// Key will parse and return the appropriately typed key for the selected signature method
+func (opts *jwtOptions) Key() (any, error) {
+	switch opts.SignMethod.(type) {
+	case *jwt.SigningMethodRSA, *jwt.SigningMethodRSAPSS:
+		return opts.rsaKey()
+	case *jwt.SigningMethodECDSA:
+		return opts.ecKey()
+	case *jwt.SigningMethodEd25519:
+		return opts.edKey()
+	case *jwt.SigningMethodHMAC:
+		return opts.hmacKey()
+	default:
+		return nil, fmt.Errorf("unsupported signing method: %T", opts.SignMethod)
+	}
+}
+
+func (opts *jwtOptions) hmacKey() (any, error) {
+	if len(opts.PrivateKey) == 0 {
+		return nil, ErrMissingKey
+	}
+	return opts.PrivateKey, nil
+}
+
+func (opts *jwtOptions) rsaKey() (any, error) {
+	var (
+		priv *rsa.PrivateKey
+		pub  *rsa.PublicKey
+		err  error
+	)
+
+	if len(opts.PrivateKey) > 0 {
+		priv, err = jwt.ParseRSAPrivateKeyFromPEM(opts.PrivateKey)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	if len(opts.PublicKey) > 0 {
+		pub, err = jwt.ParseRSAPublicKeyFromPEM(opts.PublicKey)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	if priv == nil {
+		if pub == nil {
+			// Neither key given
+			return nil, ErrMissingKey
+		}
+		// Public key only, can verify tokens
+		return pub, nil
+	}
+
+	// both keys provided, make sure they match
+	if pub != nil && !pub.Equal(priv.Public()) {
+		return nil, ErrKeyMismatch
+	}
+
+	return priv, nil
+}
+
+func (opts *jwtOptions) ecKey() (any, error) {
+	var (
+		priv *ecdsa.PrivateKey
+		pub  *ecdsa.PublicKey
+		err  error
+	)
+
+	if len(opts.PrivateKey) > 0 {
+		priv, err = jwt.ParseECPrivateKeyFromPEM(opts.PrivateKey)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	if len(opts.PublicKey) > 0 {
+		pub, err = jwt.ParseECPublicKeyFromPEM(opts.PublicKey)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	if priv == nil {
+		if pub == nil {
+			// Neither key given
+			return nil, ErrMissingKey
+		}
+		// Public key only, can verify tokens
+		return pub, nil
+	}
+
+	// both keys provided, make sure they match
+	if pub != nil && !pub.Equal(priv.Public()) {
+		return nil, ErrKeyMismatch
+	}
+
+	return priv, nil
+}
+
+func (opts *jwtOptions) edKey() (any, error) {
+	var (
+		priv ed25519.PrivateKey
+		pub  ed25519.PublicKey
+		err  error
+	)
+
+	if len(opts.PrivateKey) > 0 {
+		var privKey crypto.PrivateKey
+		privKey, err = jwt.ParseEdPrivateKeyFromPEM(opts.PrivateKey)
+		if err != nil {
+			return nil, err
+		}
+		priv = privKey.(ed25519.PrivateKey)
+	}
+
+	if len(opts.PublicKey) > 0 {
+		var pubKey crypto.PublicKey
+		pubKey, err = jwt.ParseEdPublicKeyFromPEM(opts.PublicKey)
+		if err != nil {
+			return nil, err
+		}
+		pub = pubKey.(ed25519.PublicKey)
+	}
+
+	if priv == nil {
+		if pub == nil {
+			// Neither key given
+			return nil, ErrMissingKey
+		}
+		// Public key only, can verify tokens
+		return pub, nil
+	}
+
+	// both keys provided, make sure they match
+	if pub != nil && !pub.Equal(priv.Public()) {
+		return nil, ErrKeyMismatch
+	}
+
+	return priv, nil
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/auth/range_perm_cache.go b/vendor/go.etcd.io/etcd/server/v3/auth/range_perm_cache.go
new file mode 100644
index 0000000..539ed29
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/auth/range_perm_cache.go
@@ -0,0 +1,204 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package auth
+
+import (
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/api/v3/authpb"
+	"go.etcd.io/etcd/pkg/v3/adt"
+)
+
+func getMergedPerms(tx UnsafeAuthReader, userName string) *unifiedRangePermissions {
+	user := tx.UnsafeGetUser(userName)
+	if user == nil {
+		return nil
+	}
+
+	readPerms := adt.NewIntervalTree()
+	writePerms := adt.NewIntervalTree()
+
+	for _, roleName := range user.Roles {
+		role := tx.UnsafeGetRole(roleName)
+		if role == nil {
+			continue
+		}
+
+		for _, perm := range role.KeyPermission {
+			var ivl adt.Interval
+			var rangeEnd []byte
+
+			if len(perm.RangeEnd) != 1 || perm.RangeEnd[0] != 0 {
+				rangeEnd = perm.RangeEnd
+			}
+
+			if len(perm.RangeEnd) != 0 {
+				ivl = adt.NewBytesAffineInterval(perm.Key, rangeEnd)
+			} else {
+				ivl = adt.NewBytesAffinePoint(perm.Key)
+			}
+
+			switch perm.PermType {
+			case authpb.READWRITE:
+				readPerms.Insert(ivl, struct{}{})
+				writePerms.Insert(ivl, struct{}{})
+
+			case authpb.READ:
+				readPerms.Insert(ivl, struct{}{})
+
+			case authpb.WRITE:
+				writePerms.Insert(ivl, struct{}{})
+			}
+		}
+	}
+
+	return &unifiedRangePermissions{
+		readPerms:  readPerms,
+		writePerms: writePerms,
+	}
+}
+
+func checkKeyInterval(
+	lg *zap.Logger,
+	cachedPerms *unifiedRangePermissions,
+	key, rangeEnd []byte,
+	permtyp authpb.Permission_Type,
+) bool {
+	if isOpenEnded(rangeEnd) {
+		rangeEnd = nil
+		// nil rangeEnd will be converetd to []byte{}, the largest element of BytesAffineComparable,
+		// in NewBytesAffineInterval().
+	}
+
+	ivl := adt.NewBytesAffineInterval(key, rangeEnd)
+	switch permtyp {
+	case authpb.READ:
+		return cachedPerms.readPerms.Contains(ivl)
+	case authpb.WRITE:
+		return cachedPerms.writePerms.Contains(ivl)
+	default:
+		lg.Panic("unknown auth type", zap.String("auth-type", permtyp.String()))
+	}
+	return false
+}
+
+func checkKeyPoint(lg *zap.Logger, cachedPerms *unifiedRangePermissions, key []byte, permtyp authpb.Permission_Type) bool {
+	pt := adt.NewBytesAffinePoint(key)
+	switch permtyp {
+	case authpb.READ:
+		return cachedPerms.readPerms.Intersects(pt)
+	case authpb.WRITE:
+		return cachedPerms.writePerms.Intersects(pt)
+	default:
+		lg.Panic("unknown auth type", zap.String("auth-type", permtyp.String()))
+	}
+	return false
+}
+
+func (as *authStore) isRangeOpPermitted(userName string, key, rangeEnd []byte, permtyp authpb.Permission_Type) bool {
+	// assumption: tx is Lock()ed
+	as.rangePermCacheMu.RLock()
+	defer as.rangePermCacheMu.RUnlock()
+
+	rangePerm, ok := as.rangePermCache[userName]
+	if !ok {
+		as.lg.Error(
+			"user doesn't exist",
+			zap.String("user-name", userName),
+		)
+		return false
+	}
+
+	if len(rangeEnd) == 0 {
+		return checkKeyPoint(as.lg, rangePerm, key, permtyp)
+	}
+
+	return checkKeyInterval(as.lg, rangePerm, key, rangeEnd, permtyp)
+}
+
+func (as *authStore) refreshRangePermCache(tx UnsafeAuthReader) {
+	// Note that every authentication configuration update calls this method and it invalidates the entire
+	// rangePermCache and reconstruct it based on information of users and roles stored in the backend.
+	// This can be a costly operation.
+	as.rangePermCacheMu.Lock()
+	defer as.rangePermCacheMu.Unlock()
+
+	as.lg.Debug("Refreshing rangePermCache")
+
+	as.rangePermCache = make(map[string]*unifiedRangePermissions)
+
+	users := tx.UnsafeGetAllUsers()
+	for _, user := range users {
+		userName := string(user.Name)
+		perms := getMergedPerms(tx, userName)
+		if perms == nil {
+			as.lg.Error(
+				"failed to create a merged permission",
+				zap.String("user-name", userName),
+			)
+			continue
+		}
+		as.rangePermCache[userName] = perms
+	}
+}
+
+type unifiedRangePermissions struct {
+	readPerms  adt.IntervalTree
+	writePerms adt.IntervalTree
+}
+
+// Constraints related to key range
+// Assumptions:
+// a1. key must be non-nil
+// a2. []byte{} (in the case of string, "") is not a valid key of etcd
+// For representing an open-ended range, BytesAffineComparable uses []byte{} as the largest element.
+// a3. []byte{0x00} is the minimum valid etcd key
+//
+// Based on the above assumptions, key and rangeEnd must follow below rules:
+// b1. for representing a single key point, rangeEnd should be nil or zero length byte array (in the case of string, "")
+// Rule a2 guarantees that (X, []byte{}) for any X is not a valid range. So such ranges can be used for representing
+// a single key permission.
+//
+// b2. key range with upper limit, like (X, Y), larger or equal to X and smaller than Y
+//
+// b3. key range with open-ended, like (X, <open ended>), is represented like (X, []byte{0x00})
+// Because of rule a3, if we have (X, []byte{0x00}), such a range represents an empty range and makes no sense to have
+// such a permission. So we use []byte{0x00} for representing an open-ended permission.
+// Note that rangeEnd with []byte{0x00} will be converted into []byte{} before inserted into the interval tree
+// (rule a2 ensures that this is the largest element).
+// Special range like key = []byte{0x00} and rangeEnd = []byte{0x00} is treated as a range which matches with all keys.
+//
+// Treating a range whose rangeEnd with []byte{0x00} as an open-ended comes from the rules of Range() and Watch() API.
+
+func isOpenEnded(rangeEnd []byte) bool { // check rule b3
+	return len(rangeEnd) == 1 && rangeEnd[0] == 0
+}
+
+func isValidPermissionRange(key, rangeEnd []byte) bool {
+	if len(key) == 0 {
+		return false
+	}
+	if len(rangeEnd) == 0 { // ensure rule b1
+		return true
+	}
+
+	begin := adt.BytesAffineComparable(key)
+	end := adt.BytesAffineComparable(rangeEnd)
+	if begin.Compare(end) == -1 { // rule b2
+		return true
+	}
+
+	return isOpenEnded(rangeEnd)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/auth/simple_token.go b/vendor/go.etcd.io/etcd/server/v3/auth/simple_token.go
new file mode 100644
index 0000000..f8272b1
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/auth/simple_token.go
@@ -0,0 +1,257 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package auth
+
+// CAUTION: This random number based token mechanism is only for testing purpose.
+// JWT based mechanism will be added in the near future.
+
+import (
+	"context"
+	"crypto/rand"
+	"errors"
+	"fmt"
+	"math/big"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	"go.uber.org/zap"
+)
+
+const (
+	letters                  = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
+	defaultSimpleTokenLength = 16
+)
+
+// var for testing purposes
+// TODO: Remove this mutable global state - as it's race-prone.
+var (
+	simpleTokenTTLDefault    = 300 * time.Second
+	simpleTokenTTLResolution = 1 * time.Second
+)
+
+type simpleTokenTTLKeeper struct {
+	tokens          map[string]time.Time
+	donec           chan struct{}
+	stopc           chan struct{}
+	deleteTokenFunc func(string)
+	mu              *sync.Mutex
+	simpleTokenTTL  time.Duration
+}
+
+func (tm *simpleTokenTTLKeeper) stop() {
+	select {
+	case tm.stopc <- struct{}{}:
+	case <-tm.donec:
+	}
+	<-tm.donec
+}
+
+func (tm *simpleTokenTTLKeeper) addSimpleToken(token string) {
+	tm.tokens[token] = time.Now().Add(tm.simpleTokenTTL)
+}
+
+func (tm *simpleTokenTTLKeeper) resetSimpleToken(token string) {
+	if _, ok := tm.tokens[token]; ok {
+		tm.tokens[token] = time.Now().Add(tm.simpleTokenTTL)
+	}
+}
+
+func (tm *simpleTokenTTLKeeper) deleteSimpleToken(token string) {
+	delete(tm.tokens, token)
+}
+
+func (tm *simpleTokenTTLKeeper) run() {
+	tokenTicker := time.NewTicker(simpleTokenTTLResolution)
+	defer func() {
+		tokenTicker.Stop()
+		close(tm.donec)
+	}()
+	for {
+		select {
+		case <-tokenTicker.C:
+			nowtime := time.Now()
+			tm.mu.Lock()
+			for t, tokenendtime := range tm.tokens {
+				if nowtime.After(tokenendtime) {
+					tm.deleteTokenFunc(t)
+					delete(tm.tokens, t)
+				}
+			}
+			tm.mu.Unlock()
+		case <-tm.stopc:
+			return
+		}
+	}
+}
+
+type tokenSimple struct {
+	lg                *zap.Logger
+	indexWaiter       func(uint64) <-chan struct{}
+	simpleTokenKeeper *simpleTokenTTLKeeper
+	simpleTokensMu    sync.Mutex
+	simpleTokens      map[string]string // token -> username
+	simpleTokenTTL    time.Duration
+}
+
+func (t *tokenSimple) genTokenPrefix() (string, error) {
+	ret := make([]byte, defaultSimpleTokenLength)
+
+	for i := 0; i < defaultSimpleTokenLength; i++ {
+		bInt, err := rand.Int(rand.Reader, big.NewInt(int64(len(letters))))
+		if err != nil {
+			return "", err
+		}
+
+		ret[i] = letters[bInt.Int64()]
+	}
+
+	return string(ret), nil
+}
+
+func (t *tokenSimple) assignSimpleTokenToUser(username, token string) {
+	t.simpleTokensMu.Lock()
+	defer t.simpleTokensMu.Unlock()
+	if t.simpleTokenKeeper == nil {
+		return
+	}
+
+	_, ok := t.simpleTokens[token]
+	if ok {
+		t.lg.Panic(
+			"failed to assign already-used simple token to a user",
+			zap.String("user-name", username),
+			zap.String("token", token),
+		)
+	}
+
+	t.simpleTokens[token] = username
+	t.simpleTokenKeeper.addSimpleToken(token)
+}
+
+func (t *tokenSimple) invalidateUser(username string) {
+	if t.simpleTokenKeeper == nil {
+		return
+	}
+	t.simpleTokensMu.Lock()
+	for token, name := range t.simpleTokens {
+		if name == username {
+			delete(t.simpleTokens, token)
+			t.simpleTokenKeeper.deleteSimpleToken(token)
+		}
+	}
+	t.simpleTokensMu.Unlock()
+}
+
+func (t *tokenSimple) enable() {
+	t.simpleTokensMu.Lock()
+	defer t.simpleTokensMu.Unlock()
+	if t.simpleTokenKeeper != nil { // already enabled
+		return
+	}
+	if t.simpleTokenTTL <= 0 {
+		t.simpleTokenTTL = simpleTokenTTLDefault
+	}
+
+	delf := func(tk string) {
+		if username, ok := t.simpleTokens[tk]; ok {
+			t.lg.Debug(
+				"deleted a simple token",
+				zap.String("user-name", username),
+				zap.String("token", tk),
+			)
+			delete(t.simpleTokens, tk)
+		}
+	}
+	t.simpleTokenKeeper = &simpleTokenTTLKeeper{
+		tokens:          make(map[string]time.Time),
+		donec:           make(chan struct{}),
+		stopc:           make(chan struct{}),
+		deleteTokenFunc: delf,
+		mu:              &t.simpleTokensMu,
+		simpleTokenTTL:  t.simpleTokenTTL,
+	}
+	go t.simpleTokenKeeper.run()
+}
+
+func (t *tokenSimple) disable() {
+	t.simpleTokensMu.Lock()
+	tk := t.simpleTokenKeeper
+	t.simpleTokenKeeper = nil
+	t.simpleTokens = make(map[string]string) // invalidate all tokens
+	t.simpleTokensMu.Unlock()
+	if tk != nil {
+		tk.stop()
+	}
+}
+
+func (t *tokenSimple) info(ctx context.Context, token string, revision uint64) (*AuthInfo, bool) {
+	if !t.isValidSimpleToken(ctx, token) {
+		return nil, false
+	}
+	t.simpleTokensMu.Lock()
+	username, ok := t.simpleTokens[token]
+	if ok && t.simpleTokenKeeper != nil {
+		t.simpleTokenKeeper.resetSimpleToken(token)
+	}
+	t.simpleTokensMu.Unlock()
+	return &AuthInfo{Username: username, Revision: revision}, ok
+}
+
+func (t *tokenSimple) assign(ctx context.Context, username string, rev uint64) (string, error) {
+	// rev isn't used in simple token, it is only used in JWT
+	var index uint64
+	var ok bool
+	if index, ok = ctx.Value(AuthenticateParamIndex{}).(uint64); !ok {
+		return "", errors.New("failed to assign")
+	}
+	simpleTokenPrefix := ctx.Value(AuthenticateParamSimpleTokenPrefix{}).(string)
+	token := fmt.Sprintf("%s.%d", simpleTokenPrefix, index)
+	t.assignSimpleTokenToUser(username, token)
+
+	return token, nil
+}
+
+func (t *tokenSimple) isValidSimpleToken(ctx context.Context, token string) bool {
+	splitted := strings.Split(token, ".")
+	if len(splitted) != 2 {
+		return false
+	}
+	index, err := strconv.ParseUint(splitted[1], 10, 0)
+	if err != nil {
+		return false
+	}
+
+	select {
+	case <-t.indexWaiter(index):
+		return true
+	case <-ctx.Done():
+	}
+
+	return false
+}
+
+func newTokenProviderSimple(lg *zap.Logger, indexWaiter func(uint64) <-chan struct{}, TokenTTL time.Duration) *tokenSimple {
+	if lg == nil {
+		lg = zap.NewNop()
+	}
+	return &tokenSimple{
+		lg:             lg,
+		simpleTokens:   make(map[string]string),
+		indexWaiter:    indexWaiter,
+		simpleTokenTTL: TokenTTL,
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/auth/store.go b/vendor/go.etcd.io/etcd/server/v3/auth/store.go
new file mode 100644
index 0000000..cfacfb0
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/auth/store.go
@@ -0,0 +1,1230 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package auth
+
+import (
+	"bytes"
+	"context"
+	"encoding/base64"
+	"errors"
+	"sort"
+	"strings"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"go.uber.org/zap"
+	"golang.org/x/crypto/bcrypt"
+	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/metadata"
+	"google.golang.org/grpc/peer"
+
+	"go.etcd.io/etcd/api/v3/authpb"
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/api/v3/v3rpc/rpctypes"
+)
+
+var _ AuthStore = (*authStore)(nil)
+
+var (
+	rootPerm = authpb.Permission{PermType: authpb.READWRITE, Key: []byte{}, RangeEnd: []byte{0}}
+
+	ErrRootUserNotExist     = errors.New("auth: root user does not exist")
+	ErrRootRoleNotExist     = errors.New("auth: root user does not have root role")
+	ErrUserAlreadyExist     = errors.New("auth: user already exists")
+	ErrUserEmpty            = errors.New("auth: user name is empty")
+	ErrUserNotFound         = errors.New("auth: user not found")
+	ErrRoleAlreadyExist     = errors.New("auth: role already exists")
+	ErrRoleNotFound         = errors.New("auth: role not found")
+	ErrRoleEmpty            = errors.New("auth: role name is empty")
+	ErrPermissionNotGiven   = errors.New("auth: permission not given")
+	ErrAuthFailed           = errors.New("auth: authentication failed, invalid user ID or password")
+	ErrNoPasswordUser       = errors.New("auth: authentication failed, password was given for no password user")
+	ErrPermissionDenied     = errors.New("auth: permission denied")
+	ErrRoleNotGranted       = errors.New("auth: role is not granted to the user")
+	ErrPermissionNotGranted = errors.New("auth: permission is not granted to the role")
+	ErrAuthNotEnabled       = errors.New("auth: authentication is not enabled")
+	ErrAuthOldRevision      = errors.New("auth: revision in header is old")
+	ErrInvalidAuthToken     = errors.New("auth: invalid auth token")
+	ErrInvalidAuthOpts      = errors.New("auth: invalid auth options")
+	ErrInvalidAuthMgmt      = errors.New("auth: invalid auth management")
+	ErrInvalidAuthMethod    = errors.New("auth: invalid auth signature method")
+	ErrMissingKey           = errors.New("auth: missing key data")
+	ErrKeyMismatch          = errors.New("auth: public and private keys don't match")
+	ErrVerifyOnly           = errors.New("auth: token signing attempted with verify-only key")
+)
+
+const (
+	rootUser = "root"
+	rootRole = "root"
+
+	tokenTypeSimple = "simple"
+	tokenTypeJWT    = "jwt"
+)
+
+type AuthInfo struct {
+	Username string
+	Revision uint64
+}
+
+// AuthenticateParamIndex is used for a key of context in the parameters of Authenticate()
+type AuthenticateParamIndex struct{}
+
+// AuthenticateParamSimpleTokenPrefix is used for a key of context in the parameters of Authenticate()
+type AuthenticateParamSimpleTokenPrefix struct{}
+
+// AuthStore defines auth storage interface.
+type AuthStore interface {
+	// AuthEnable turns on the authentication feature
+	AuthEnable() error
+
+	// AuthDisable turns off the authentication feature
+	AuthDisable()
+
+	// IsAuthEnabled returns true if the authentication feature is enabled.
+	IsAuthEnabled() bool
+
+	// Authenticate does authentication based on given user name and password
+	Authenticate(ctx context.Context, username, password string) (*pb.AuthenticateResponse, error)
+
+	// Recover recovers the state of auth store from the given backend
+	Recover(be AuthBackend)
+
+	// UserAdd adds a new user
+	UserAdd(r *pb.AuthUserAddRequest) (*pb.AuthUserAddResponse, error)
+
+	// UserDelete deletes a user
+	UserDelete(r *pb.AuthUserDeleteRequest) (*pb.AuthUserDeleteResponse, error)
+
+	// UserChangePassword changes a password of a user
+	UserChangePassword(r *pb.AuthUserChangePasswordRequest) (*pb.AuthUserChangePasswordResponse, error)
+
+	// UserGrantRole grants a role to the user
+	UserGrantRole(r *pb.AuthUserGrantRoleRequest) (*pb.AuthUserGrantRoleResponse, error)
+
+	// UserGet gets the detailed information of a users
+	UserGet(r *pb.AuthUserGetRequest) (*pb.AuthUserGetResponse, error)
+
+	// UserRevokeRole revokes a role of a user
+	UserRevokeRole(r *pb.AuthUserRevokeRoleRequest) (*pb.AuthUserRevokeRoleResponse, error)
+
+	// RoleAdd adds a new role
+	RoleAdd(r *pb.AuthRoleAddRequest) (*pb.AuthRoleAddResponse, error)
+
+	// RoleGrantPermission grants a permission to a role
+	RoleGrantPermission(r *pb.AuthRoleGrantPermissionRequest) (*pb.AuthRoleGrantPermissionResponse, error)
+
+	// RoleGet gets the detailed information of a role
+	RoleGet(r *pb.AuthRoleGetRequest) (*pb.AuthRoleGetResponse, error)
+
+	// RoleRevokePermission gets the detailed information of a role
+	RoleRevokePermission(r *pb.AuthRoleRevokePermissionRequest) (*pb.AuthRoleRevokePermissionResponse, error)
+
+	// RoleDelete gets the detailed information of a role
+	RoleDelete(r *pb.AuthRoleDeleteRequest) (*pb.AuthRoleDeleteResponse, error)
+
+	// UserList gets a list of all users
+	UserList(r *pb.AuthUserListRequest) (*pb.AuthUserListResponse, error)
+
+	// RoleList gets a list of all roles
+	RoleList(r *pb.AuthRoleListRequest) (*pb.AuthRoleListResponse, error)
+
+	// IsPutPermitted checks put permission of the user
+	IsPutPermitted(authInfo *AuthInfo, key []byte) error
+
+	// IsRangePermitted checks range permission of the user
+	IsRangePermitted(authInfo *AuthInfo, key, rangeEnd []byte) error
+
+	// IsDeleteRangePermitted checks delete-range permission of the user
+	IsDeleteRangePermitted(authInfo *AuthInfo, key, rangeEnd []byte) error
+
+	// IsAdminPermitted checks admin permission of the user
+	IsAdminPermitted(authInfo *AuthInfo) error
+
+	// GenTokenPrefix produces a random string in a case of simple token
+	// in a case of JWT, it produces an empty string
+	GenTokenPrefix() (string, error)
+
+	// Revision gets current revision of authStore
+	Revision() uint64
+
+	// CheckPassword checks a given pair of username and password is correct
+	CheckPassword(username, password string) (uint64, error)
+
+	// Close does cleanup of AuthStore
+	Close() error
+
+	// AuthInfoFromCtx gets AuthInfo from gRPC's context
+	AuthInfoFromCtx(ctx context.Context) (*AuthInfo, error)
+
+	// AuthInfoFromTLS gets AuthInfo from TLS info of gRPC's context
+	AuthInfoFromTLS(ctx context.Context) *AuthInfo
+
+	// WithRoot generates and installs a token that can be used as a root credential
+	WithRoot(ctx context.Context) context.Context
+
+	// HasRole checks that user has role
+	HasRole(user, role string) bool
+
+	// BcryptCost gets strength of hashing bcrypted auth password
+	BcryptCost() int
+}
+
+type TokenProvider interface {
+	info(ctx context.Context, token string, revision uint64) (*AuthInfo, bool)
+	assign(ctx context.Context, username string, revision uint64) (string, error)
+	enable()
+	disable()
+
+	invalidateUser(string)
+	genTokenPrefix() (string, error)
+}
+
+type AuthBackend interface {
+	CreateAuthBuckets()
+	ForceCommit()
+	ReadTx() AuthReadTx
+	BatchTx() AuthBatchTx
+
+	GetUser(string) *authpb.User
+	GetAllUsers() []*authpb.User
+	GetRole(string) *authpb.Role
+	GetAllRoles() []*authpb.Role
+}
+
+type AuthReadTx interface {
+	RLock()
+	RUnlock()
+	UnsafeAuthReader
+}
+
+type UnsafeAuthReader interface {
+	UnsafeReadAuthEnabled() bool
+	UnsafeReadAuthRevision() uint64
+	UnsafeGetUser(string) *authpb.User
+	UnsafeGetRole(string) *authpb.Role
+	UnsafeGetAllUsers() []*authpb.User
+	UnsafeGetAllRoles() []*authpb.Role
+}
+
+type AuthBatchTx interface {
+	Lock()
+	Unlock()
+	UnsafeAuthReadWriter
+}
+
+type UnsafeAuthReadWriter interface {
+	UnsafeAuthReader
+	UnsafeAuthWriter
+}
+
+type UnsafeAuthWriter interface {
+	UnsafeSaveAuthEnabled(enabled bool)
+	UnsafeSaveAuthRevision(rev uint64)
+	UnsafePutUser(*authpb.User)
+	UnsafeDeleteUser(string)
+	UnsafePutRole(*authpb.Role)
+	UnsafeDeleteRole(string)
+}
+
+type authStore struct {
+	// atomic operations; need 64-bit align, or 32-bit tests will crash
+	revision uint64
+
+	lg        *zap.Logger
+	be        AuthBackend
+	enabled   bool
+	enabledMu sync.RWMutex
+
+	// rangePermCache needs to be protected by rangePermCacheMu
+	// rangePermCacheMu needs to be write locked only in initialization phase or configuration changes
+	// Hot paths like Range(), needs to acquire read lock for improving performance
+	//
+	// Note that BatchTx and ReadTx cannot be a mutex for rangePermCache because they are independent resources
+	// see also: https://github.com/etcd-io/etcd/pull/13920#discussion_r849114855
+	rangePermCache   map[string]*unifiedRangePermissions // username -> unifiedRangePermissions
+	rangePermCacheMu sync.RWMutex
+
+	tokenProvider TokenProvider
+	bcryptCost    int // the algorithm cost / strength for hashing auth passwords
+}
+
+func (as *authStore) AuthEnable() error {
+	as.enabledMu.Lock()
+	defer as.enabledMu.Unlock()
+	if as.enabled {
+		as.lg.Info("authentication is already enabled; ignored auth enable request")
+		return nil
+	}
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer func() {
+		tx.Unlock()
+		as.be.ForceCommit()
+	}()
+
+	u := tx.UnsafeGetUser(rootUser)
+	if u == nil {
+		return ErrRootUserNotExist
+	}
+
+	if !hasRootRole(u) {
+		return ErrRootRoleNotExist
+	}
+
+	tx.UnsafeSaveAuthEnabled(true)
+	as.enabled = true
+	as.tokenProvider.enable()
+
+	as.refreshRangePermCache(tx)
+
+	as.setRevision(tx.UnsafeReadAuthRevision())
+
+	as.lg.Info("enabled authentication")
+	return nil
+}
+
+func (as *authStore) AuthDisable() {
+	as.enabledMu.Lock()
+	defer as.enabledMu.Unlock()
+	if !as.enabled {
+		return
+	}
+	b := as.be
+
+	tx := b.BatchTx()
+	tx.Lock()
+	tx.UnsafeSaveAuthEnabled(false)
+	as.commitRevision(tx)
+	tx.Unlock()
+
+	b.ForceCommit()
+
+	as.enabled = false
+	as.tokenProvider.disable()
+
+	as.lg.Info("disabled authentication")
+}
+
+func (as *authStore) Close() error {
+	as.enabledMu.Lock()
+	defer as.enabledMu.Unlock()
+	if !as.enabled {
+		return nil
+	}
+	as.tokenProvider.disable()
+	return nil
+}
+
+func (as *authStore) Authenticate(ctx context.Context, username, password string) (*pb.AuthenticateResponse, error) {
+	if !as.IsAuthEnabled() {
+		return nil, ErrAuthNotEnabled
+	}
+	user := as.be.GetUser(username)
+	if user == nil {
+		return nil, ErrAuthFailed
+	}
+
+	if user.Options != nil && user.Options.NoPassword {
+		return nil, ErrAuthFailed
+	}
+
+	// Password checking is already performed in the API layer, so we don't need to check for now.
+	// Staleness of password can be detected with OCC in the API layer, too.
+
+	token, err := as.tokenProvider.assign(ctx, username, as.Revision())
+	if err != nil {
+		return nil, err
+	}
+
+	as.lg.Debug(
+		"authenticated a user",
+		zap.String("user-name", username),
+		zap.String("token", token),
+	)
+	return &pb.AuthenticateResponse{Token: token}, nil
+}
+
+func (as *authStore) CheckPassword(username, password string) (uint64, error) {
+	if !as.IsAuthEnabled() {
+		return 0, ErrAuthNotEnabled
+	}
+
+	var user *authpb.User
+	// CompareHashAndPassword is very expensive, so we use closures
+	// to avoid putting it in the critical section of the tx lock.
+	revision, err := func() (uint64, error) {
+		tx := as.be.ReadTx()
+		tx.RLock()
+		defer tx.RUnlock()
+
+		user = tx.UnsafeGetUser(username)
+		if user == nil {
+			return 0, ErrAuthFailed
+		}
+
+		if user.Options != nil && user.Options.NoPassword {
+			return 0, ErrNoPasswordUser
+		}
+
+		return tx.UnsafeReadAuthRevision(), nil
+	}()
+	if err != nil {
+		return 0, err
+	}
+
+	if bcrypt.CompareHashAndPassword(user.Password, []byte(password)) != nil {
+		as.lg.Info("invalid password", zap.String("user-name", username))
+		return 0, ErrAuthFailed
+	}
+	return revision, nil
+}
+
+func (as *authStore) Recover(be AuthBackend) {
+	as.be = be
+	tx := be.ReadTx()
+	tx.RLock()
+
+	enabled := tx.UnsafeReadAuthEnabled()
+	as.setRevision(tx.UnsafeReadAuthRevision())
+	as.refreshRangePermCache(tx)
+
+	tx.RUnlock()
+
+	as.enabledMu.Lock()
+	as.enabled = enabled
+	if enabled {
+		as.tokenProvider.enable()
+	}
+	as.enabledMu.Unlock()
+}
+
+func (as *authStore) selectPassword(password string, hashedPassword string) ([]byte, error) {
+	if password != "" && hashedPassword == "" {
+		// This path is for processing log entries created by etcd whose version is older than 3.5
+		return bcrypt.GenerateFromPassword([]byte(password), as.bcryptCost)
+	}
+	return base64.StdEncoding.DecodeString(hashedPassword)
+}
+
+func (as *authStore) UserAdd(r *pb.AuthUserAddRequest) (*pb.AuthUserAddResponse, error) {
+	if len(r.Name) == 0 {
+		return nil, ErrUserEmpty
+	}
+
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	user := tx.UnsafeGetUser(r.Name)
+	if user != nil {
+		return nil, ErrUserAlreadyExist
+	}
+
+	options := r.Options
+	if options == nil {
+		options = &authpb.UserAddOptions{
+			NoPassword: false,
+		}
+	}
+
+	var password []byte
+	var err error
+
+	if !options.NoPassword {
+		password, err = as.selectPassword(r.Password, r.HashedPassword)
+		if err != nil {
+			return nil, ErrNoPasswordUser
+		}
+	}
+
+	newUser := &authpb.User{
+		Name:     []byte(r.Name),
+		Password: password,
+		Options:  options,
+	}
+	tx.UnsafePutUser(newUser)
+
+	as.commitRevision(tx)
+	as.refreshRangePermCache(tx)
+
+	as.lg.Info("added a user", zap.String("user-name", r.Name))
+	return &pb.AuthUserAddResponse{}, nil
+}
+
+func (as *authStore) UserDelete(r *pb.AuthUserDeleteRequest) (*pb.AuthUserDeleteResponse, error) {
+	if as.enabled && r.Name == rootUser {
+		as.lg.Error("cannot delete 'root' user", zap.String("user-name", r.Name))
+		return nil, ErrInvalidAuthMgmt
+	}
+
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	user := tx.UnsafeGetUser(r.Name)
+	if user == nil {
+		return nil, ErrUserNotFound
+	}
+	tx.UnsafeDeleteUser(r.Name)
+
+	as.commitRevision(tx)
+	as.refreshRangePermCache(tx)
+
+	as.tokenProvider.invalidateUser(r.Name)
+
+	as.lg.Info(
+		"deleted a user",
+		zap.String("user-name", r.Name),
+		zap.Strings("user-roles", user.Roles),
+	)
+	return &pb.AuthUserDeleteResponse{}, nil
+}
+
+func (as *authStore) UserChangePassword(r *pb.AuthUserChangePasswordRequest) (*pb.AuthUserChangePasswordResponse, error) {
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	user := tx.UnsafeGetUser(r.Name)
+	if user == nil {
+		return nil, ErrUserNotFound
+	}
+
+	var password []byte
+	var err error
+
+	// Backward compatible with old versions of etcd, user options is nil
+	if user.Options == nil || !user.Options.NoPassword {
+		password, err = as.selectPassword(r.Password, r.HashedPassword)
+		if err != nil {
+			return nil, ErrNoPasswordUser
+		}
+	}
+
+	updatedUser := &authpb.User{
+		Name:     []byte(r.Name),
+		Roles:    user.Roles,
+		Password: password,
+		Options:  user.Options,
+	}
+	tx.UnsafePutUser(updatedUser)
+
+	as.commitRevision(tx)
+	as.refreshRangePermCache(tx)
+
+	as.tokenProvider.invalidateUser(r.Name)
+
+	as.lg.Info(
+		"changed a password of a user",
+		zap.String("user-name", r.Name),
+		zap.Strings("user-roles", user.Roles),
+	)
+	return &pb.AuthUserChangePasswordResponse{}, nil
+}
+
+func (as *authStore) UserGrantRole(r *pb.AuthUserGrantRoleRequest) (*pb.AuthUserGrantRoleResponse, error) {
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	user := tx.UnsafeGetUser(r.User)
+	if user == nil {
+		return nil, ErrUserNotFound
+	}
+
+	if r.Role != rootRole {
+		role := tx.UnsafeGetRole(r.Role)
+		if role == nil {
+			return nil, ErrRoleNotFound
+		}
+	}
+
+	idx := sort.SearchStrings(user.Roles, r.Role)
+	if idx < len(user.Roles) && user.Roles[idx] == r.Role {
+		as.lg.Warn(
+			"ignored grant role request to a user",
+			zap.String("user-name", r.User),
+			zap.Strings("user-roles", user.Roles),
+			zap.String("duplicate-role-name", r.Role),
+		)
+		return &pb.AuthUserGrantRoleResponse{}, nil
+	}
+
+	user.Roles = append(user.Roles, r.Role)
+	sort.Strings(user.Roles)
+
+	tx.UnsafePutUser(user)
+
+	as.commitRevision(tx)
+	as.refreshRangePermCache(tx)
+
+	as.lg.Info(
+		"granted a role to a user",
+		zap.String("user-name", r.User),
+		zap.Strings("user-roles", user.Roles),
+		zap.String("added-role-name", r.Role),
+	)
+	return &pb.AuthUserGrantRoleResponse{}, nil
+}
+
+func (as *authStore) UserGet(r *pb.AuthUserGetRequest) (*pb.AuthUserGetResponse, error) {
+	user := as.be.GetUser(r.Name)
+
+	if user == nil {
+		return nil, ErrUserNotFound
+	}
+
+	var resp pb.AuthUserGetResponse
+	resp.Roles = append(resp.Roles, user.Roles...)
+	return &resp, nil
+}
+
+func (as *authStore) UserList(r *pb.AuthUserListRequest) (*pb.AuthUserListResponse, error) {
+	users := as.be.GetAllUsers()
+
+	resp := &pb.AuthUserListResponse{Users: make([]string, len(users))}
+	for i := range users {
+		resp.Users[i] = string(users[i].Name)
+	}
+	return resp, nil
+}
+
+func (as *authStore) UserRevokeRole(r *pb.AuthUserRevokeRoleRequest) (*pb.AuthUserRevokeRoleResponse, error) {
+	if as.enabled && r.Name == rootUser && r.Role == rootRole {
+		as.lg.Error(
+			"'root' user cannot revoke 'root' role",
+			zap.String("user-name", r.Name),
+			zap.String("role-name", r.Role),
+		)
+		return nil, ErrInvalidAuthMgmt
+	}
+
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	user := tx.UnsafeGetUser(r.Name)
+	if user == nil {
+		return nil, ErrUserNotFound
+	}
+
+	updatedUser := &authpb.User{
+		Name:     user.Name,
+		Password: user.Password,
+		Options:  user.Options,
+	}
+
+	for _, role := range user.Roles {
+		if role != r.Role {
+			updatedUser.Roles = append(updatedUser.Roles, role)
+		}
+	}
+
+	if len(updatedUser.Roles) == len(user.Roles) {
+		return nil, ErrRoleNotGranted
+	}
+
+	tx.UnsafePutUser(updatedUser)
+
+	as.commitRevision(tx)
+	as.refreshRangePermCache(tx)
+
+	as.lg.Info(
+		"revoked a role from a user",
+		zap.String("user-name", r.Name),
+		zap.Strings("old-user-roles", user.Roles),
+		zap.Strings("new-user-roles", updatedUser.Roles),
+		zap.String("revoked-role-name", r.Role),
+	)
+	return &pb.AuthUserRevokeRoleResponse{}, nil
+}
+
+func (as *authStore) RoleGet(r *pb.AuthRoleGetRequest) (*pb.AuthRoleGetResponse, error) {
+	var resp pb.AuthRoleGetResponse
+
+	role := as.be.GetRole(r.Role)
+	if role == nil {
+		return nil, ErrRoleNotFound
+	}
+	if rootRole == string(role.Name) {
+		resp.Perm = append(resp.Perm, &rootPerm)
+	} else {
+		resp.Perm = append(resp.Perm, role.KeyPermission...)
+	}
+	return &resp, nil
+}
+
+func (as *authStore) RoleList(r *pb.AuthRoleListRequest) (*pb.AuthRoleListResponse, error) {
+	roles := as.be.GetAllRoles()
+
+	resp := &pb.AuthRoleListResponse{Roles: make([]string, len(roles))}
+	for i := range roles {
+		resp.Roles[i] = string(roles[i].Name)
+	}
+	return resp, nil
+}
+
+func (as *authStore) RoleRevokePermission(r *pb.AuthRoleRevokePermissionRequest) (*pb.AuthRoleRevokePermissionResponse, error) {
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	role := tx.UnsafeGetRole(r.Role)
+	if role == nil {
+		return nil, ErrRoleNotFound
+	}
+
+	updatedRole := &authpb.Role{
+		Name: role.Name,
+	}
+
+	for _, perm := range role.KeyPermission {
+		if !bytes.Equal(perm.Key, r.Key) || !bytes.Equal(perm.RangeEnd, r.RangeEnd) {
+			updatedRole.KeyPermission = append(updatedRole.KeyPermission, perm)
+		}
+	}
+
+	if len(role.KeyPermission) == len(updatedRole.KeyPermission) {
+		return nil, ErrPermissionNotGranted
+	}
+
+	tx.UnsafePutRole(updatedRole)
+
+	as.commitRevision(tx)
+	as.refreshRangePermCache(tx)
+
+	as.lg.Info(
+		"revoked a permission on range",
+		zap.String("role-name", r.Role),
+		zap.String("key", string(r.Key)),
+		zap.String("range-end", string(r.RangeEnd)),
+	)
+	return &pb.AuthRoleRevokePermissionResponse{}, nil
+}
+
+func (as *authStore) RoleDelete(r *pb.AuthRoleDeleteRequest) (*pb.AuthRoleDeleteResponse, error) {
+	if as.enabled && r.Role == rootRole {
+		as.lg.Error("cannot delete 'root' role", zap.String("role-name", r.Role))
+		return nil, ErrInvalidAuthMgmt
+	}
+
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	role := tx.UnsafeGetRole(r.Role)
+	if role == nil {
+		return nil, ErrRoleNotFound
+	}
+
+	tx.UnsafeDeleteRole(r.Role)
+
+	users := tx.UnsafeGetAllUsers()
+	for _, user := range users {
+		updatedUser := &authpb.User{
+			Name:     user.Name,
+			Password: user.Password,
+			Options:  user.Options,
+		}
+
+		for _, role := range user.Roles {
+			if role != r.Role {
+				updatedUser.Roles = append(updatedUser.Roles, role)
+			}
+		}
+
+		if len(updatedUser.Roles) == len(user.Roles) {
+			continue
+		}
+
+		tx.UnsafePutUser(updatedUser)
+	}
+
+	as.commitRevision(tx)
+	as.refreshRangePermCache(tx)
+
+	as.lg.Info("deleted a role", zap.String("role-name", r.Role))
+	return &pb.AuthRoleDeleteResponse{}, nil
+}
+
+func (as *authStore) RoleAdd(r *pb.AuthRoleAddRequest) (*pb.AuthRoleAddResponse, error) {
+	if len(r.Name) == 0 {
+		return nil, ErrRoleEmpty
+	}
+
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	role := tx.UnsafeGetRole(r.Name)
+	if role != nil {
+		return nil, ErrRoleAlreadyExist
+	}
+
+	newRole := &authpb.Role{
+		Name: []byte(r.Name),
+	}
+
+	tx.UnsafePutRole(newRole)
+
+	as.commitRevision(tx)
+
+	as.lg.Info("created a role", zap.String("role-name", r.Name))
+	return &pb.AuthRoleAddResponse{}, nil
+}
+
+func (as *authStore) authInfoFromToken(ctx context.Context, token string) (*AuthInfo, bool) {
+	return as.tokenProvider.info(ctx, token, as.Revision())
+}
+
+type permSlice []*authpb.Permission
+
+func (perms permSlice) Len() int {
+	return len(perms)
+}
+
+func (perms permSlice) Less(i, j int) bool {
+	return bytes.Compare(perms[i].Key, perms[j].Key) < 0
+}
+
+func (perms permSlice) Swap(i, j int) {
+	perms[i], perms[j] = perms[j], perms[i]
+}
+
+func (as *authStore) RoleGrantPermission(r *pb.AuthRoleGrantPermissionRequest) (*pb.AuthRoleGrantPermissionResponse, error) {
+	if r.Perm == nil {
+		return nil, ErrPermissionNotGiven
+	}
+	if !isValidPermissionRange(r.Perm.Key, r.Perm.RangeEnd) {
+		return nil, ErrInvalidAuthMgmt
+	}
+
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	role := tx.UnsafeGetRole(r.Name)
+	if role == nil {
+		return nil, ErrRoleNotFound
+	}
+
+	idx := sort.Search(len(role.KeyPermission), func(i int) bool {
+		return bytes.Compare(role.KeyPermission[i].Key, r.Perm.Key) >= 0
+	})
+
+	if idx < len(role.KeyPermission) && bytes.Equal(role.KeyPermission[idx].Key, r.Perm.Key) && bytes.Equal(role.KeyPermission[idx].RangeEnd, r.Perm.RangeEnd) {
+		// update existing permission
+		role.KeyPermission[idx].PermType = r.Perm.PermType
+	} else {
+		// append new permission to the role
+		newPerm := &authpb.Permission{
+			Key:      r.Perm.Key,
+			RangeEnd: r.Perm.RangeEnd,
+			PermType: r.Perm.PermType,
+		}
+
+		role.KeyPermission = append(role.KeyPermission, newPerm)
+		sort.Sort(permSlice(role.KeyPermission))
+	}
+
+	tx.UnsafePutRole(role)
+
+	as.commitRevision(tx)
+	as.refreshRangePermCache(tx)
+
+	as.lg.Info(
+		"granted/updated a permission to a user",
+		zap.String("user-name", r.Name),
+		zap.String("permission-name", authpb.Permission_Type_name[int32(r.Perm.PermType)]),
+		zap.ByteString("key", r.Perm.Key),
+		zap.ByteString("range-end", r.Perm.RangeEnd),
+	)
+	return &pb.AuthRoleGrantPermissionResponse{}, nil
+}
+
+func (as *authStore) isOpPermitted(userName string, revision uint64, key, rangeEnd []byte, permTyp authpb.Permission_Type) error {
+	// TODO(mitake): this function would be costly so we need a caching mechanism
+	if !as.IsAuthEnabled() {
+		return nil
+	}
+
+	// only gets rev == 0 when passed AuthInfo{}; no user given
+	if revision == 0 {
+		return ErrUserEmpty
+	}
+	rev := as.Revision()
+	if revision < rev {
+		as.lg.Warn("request auth revision is less than current node auth revision",
+			zap.Uint64("current node auth revision", rev),
+			zap.Uint64("request auth revision", revision),
+			zap.ByteString("request key", key),
+			zap.Error(ErrAuthOldRevision))
+		return ErrAuthOldRevision
+	}
+
+	tx := as.be.ReadTx()
+	tx.RLock()
+	defer tx.RUnlock()
+
+	user := tx.UnsafeGetUser(userName)
+	if user == nil {
+		as.lg.Error("cannot find a user for permission check", zap.String("user-name", userName))
+		return ErrPermissionDenied
+	}
+
+	// root role should have permission on all ranges
+	if hasRootRole(user) {
+		return nil
+	}
+
+	if as.isRangeOpPermitted(userName, key, rangeEnd, permTyp) {
+		return nil
+	}
+
+	return ErrPermissionDenied
+}
+
+func (as *authStore) IsPutPermitted(authInfo *AuthInfo, key []byte) error {
+	return as.isOpPermitted(authInfo.Username, authInfo.Revision, key, nil, authpb.WRITE)
+}
+
+func (as *authStore) IsRangePermitted(authInfo *AuthInfo, key, rangeEnd []byte) error {
+	return as.isOpPermitted(authInfo.Username, authInfo.Revision, key, rangeEnd, authpb.READ)
+}
+
+func (as *authStore) IsDeleteRangePermitted(authInfo *AuthInfo, key, rangeEnd []byte) error {
+	return as.isOpPermitted(authInfo.Username, authInfo.Revision, key, rangeEnd, authpb.WRITE)
+}
+
+func (as *authStore) IsAdminPermitted(authInfo *AuthInfo) error {
+	if !as.IsAuthEnabled() {
+		return nil
+	}
+	if authInfo == nil || authInfo.Username == "" {
+		return ErrUserEmpty
+	}
+
+	tx := as.be.ReadTx()
+	tx.RLock()
+	defer tx.RUnlock()
+	u := tx.UnsafeGetUser(authInfo.Username)
+
+	if u == nil {
+		return ErrUserNotFound
+	}
+
+	if !hasRootRole(u) {
+		return ErrPermissionDenied
+	}
+
+	return nil
+}
+
+func (as *authStore) IsAuthEnabled() bool {
+	as.enabledMu.RLock()
+	defer as.enabledMu.RUnlock()
+	return as.enabled
+}
+
+// NewAuthStore creates a new AuthStore.
+func NewAuthStore(lg *zap.Logger, be AuthBackend, tp TokenProvider, bcryptCost int) AuthStore {
+	if lg == nil {
+		lg = zap.NewNop()
+	}
+
+	if bcryptCost < bcrypt.MinCost || bcryptCost > bcrypt.MaxCost {
+		lg.Warn(
+			"use default bcrypt cost instead of the invalid given cost",
+			zap.Int("min-cost", bcrypt.MinCost),
+			zap.Int("max-cost", bcrypt.MaxCost),
+			zap.Int("default-cost", bcrypt.DefaultCost),
+			zap.Int("given-cost", bcryptCost),
+		)
+		bcryptCost = bcrypt.DefaultCost
+	}
+
+	be.CreateAuthBuckets()
+	tx := be.BatchTx()
+	// We should call LockOutsideApply here, but the txPostLockHoos isn't set
+	// to EtcdServer yet, so it's OK.
+	tx.Lock()
+	enabled := tx.UnsafeReadAuthEnabled()
+	as := &authStore{
+		revision:       tx.UnsafeReadAuthRevision(),
+		lg:             lg,
+		be:             be,
+		enabled:        enabled,
+		rangePermCache: make(map[string]*unifiedRangePermissions),
+		tokenProvider:  tp,
+		bcryptCost:     bcryptCost,
+	}
+
+	if enabled {
+		as.tokenProvider.enable()
+	}
+
+	if as.Revision() == 0 {
+		as.commitRevision(tx)
+	}
+
+	as.setupMetricsReporter()
+
+	as.refreshRangePermCache(tx)
+
+	tx.Unlock()
+	be.ForceCommit()
+
+	return as
+}
+
+func hasRootRole(u *authpb.User) bool {
+	// u.Roles is sorted in UserGrantRole(), so we can use binary search.
+	idx := sort.SearchStrings(u.Roles, rootRole)
+	return idx != len(u.Roles) && u.Roles[idx] == rootRole
+}
+
+func (as *authStore) commitRevision(tx UnsafeAuthWriter) {
+	atomic.AddUint64(&as.revision, 1)
+	tx.UnsafeSaveAuthRevision(as.Revision())
+}
+
+func (as *authStore) setRevision(rev uint64) {
+	atomic.StoreUint64(&as.revision, rev)
+}
+
+func (as *authStore) Revision() uint64 {
+	return atomic.LoadUint64(&as.revision)
+}
+
+func (as *authStore) AuthInfoFromTLS(ctx context.Context) (ai *AuthInfo) {
+	peer, ok := peer.FromContext(ctx)
+	if !ok || peer == nil || peer.AuthInfo == nil {
+		return nil
+	}
+
+	tlsInfo := peer.AuthInfo.(credentials.TLSInfo)
+	for _, chains := range tlsInfo.State.VerifiedChains {
+		if len(chains) < 1 {
+			continue
+		}
+		ai = &AuthInfo{
+			Username: chains[0].Subject.CommonName,
+			Revision: as.Revision(),
+		}
+		md, ok := metadata.FromIncomingContext(ctx)
+		if !ok {
+			return nil
+		}
+
+		// gRPC-gateway proxy request to etcd server includes Grpcgateway-Accept
+		// header. The proxy uses etcd client server certificate. If the certificate
+		// has a CommonName we should never use this for authentication.
+		if gw := md["grpcgateway-accept"]; len(gw) > 0 {
+			as.lg.Warn(
+				"ignoring common name in gRPC-gateway proxy request",
+				zap.String("common-name", ai.Username),
+				zap.String("user-name", ai.Username),
+				zap.Uint64("revision", ai.Revision),
+			)
+			return nil
+		}
+		as.lg.Debug(
+			"found command name",
+			zap.String("common-name", ai.Username),
+			zap.String("user-name", ai.Username),
+			zap.Uint64("revision", ai.Revision),
+		)
+		break
+	}
+	return ai
+}
+
+func (as *authStore) AuthInfoFromCtx(ctx context.Context) (*AuthInfo, error) {
+	if !as.IsAuthEnabled() {
+		return nil, nil
+	}
+
+	md, ok := metadata.FromIncomingContext(ctx)
+	if !ok {
+		return nil, nil
+	}
+
+	// TODO(mitake|hexfusion) review unifying key names
+	ts, ok := md[rpctypes.TokenFieldNameGRPC]
+	if !ok {
+		ts, ok = md[rpctypes.TokenFieldNameSwagger]
+	}
+	if !ok {
+		return nil, nil
+	}
+
+	token := ts[0]
+	authInfo, uok := as.authInfoFromToken(ctx, token)
+	if !uok {
+		as.lg.Warn("invalid auth token", zap.String("token", token))
+		return nil, ErrInvalidAuthToken
+	}
+
+	return authInfo, nil
+}
+
+func (as *authStore) GenTokenPrefix() (string, error) {
+	return as.tokenProvider.genTokenPrefix()
+}
+
+func decomposeOpts(lg *zap.Logger, optstr string) (string, map[string]string, error) {
+	opts := strings.Split(optstr, ",")
+	tokenType := opts[0]
+
+	typeSpecificOpts := make(map[string]string)
+	for i := 1; i < len(opts); i++ {
+		pair := strings.Split(opts[i], "=")
+
+		if len(pair) != 2 {
+			if lg != nil {
+				lg.Error("invalid token option", zap.String("option", optstr))
+			}
+			return "", nil, ErrInvalidAuthOpts
+		}
+
+		if _, ok := typeSpecificOpts[pair[0]]; ok {
+			if lg != nil {
+				lg.Error(
+					"invalid token option",
+					zap.String("option", optstr),
+					zap.String("duplicate-parameter", pair[0]),
+				)
+			}
+			return "", nil, ErrInvalidAuthOpts
+		}
+
+		typeSpecificOpts[pair[0]] = pair[1]
+	}
+
+	return tokenType, typeSpecificOpts, nil
+}
+
+// NewTokenProvider creates a new token provider.
+func NewTokenProvider(
+	lg *zap.Logger,
+	tokenOpts string,
+	indexWaiter func(uint64) <-chan struct{},
+	TokenTTL time.Duration,
+) (TokenProvider, error) {
+	tokenType, typeSpecificOpts, err := decomposeOpts(lg, tokenOpts)
+	if err != nil {
+		return nil, ErrInvalidAuthOpts
+	}
+
+	switch tokenType {
+	case tokenTypeSimple:
+		if lg != nil {
+			lg.Warn("simple token is not cryptographically signed")
+		}
+		return newTokenProviderSimple(lg, indexWaiter, TokenTTL), nil
+
+	case tokenTypeJWT:
+		return newTokenProviderJWT(lg, typeSpecificOpts)
+
+	case "":
+		return newTokenProviderNop()
+
+	default:
+		if lg != nil {
+			lg.Warn(
+				"unknown token type",
+				zap.String("type", tokenType),
+				zap.Error(ErrInvalidAuthOpts),
+			)
+		}
+		return nil, ErrInvalidAuthOpts
+	}
+}
+
+func (as *authStore) WithRoot(ctx context.Context) context.Context {
+	if !as.IsAuthEnabled() {
+		return ctx
+	}
+
+	var ctxForAssign context.Context
+	if ts, ok := as.tokenProvider.(*tokenSimple); ok && ts != nil {
+		ctx1 := context.WithValue(ctx, AuthenticateParamIndex{}, uint64(0))
+		prefix, err := ts.genTokenPrefix()
+		if err != nil {
+			as.lg.Error(
+				"failed to generate prefix of internally used token",
+				zap.Error(err),
+			)
+			return ctx
+		}
+		ctxForAssign = context.WithValue(ctx1, AuthenticateParamSimpleTokenPrefix{}, prefix)
+	} else {
+		ctxForAssign = ctx
+	}
+
+	token, err := as.tokenProvider.assign(ctxForAssign, "root", as.Revision())
+	if err != nil {
+		// this must not happen
+		as.lg.Error(
+			"failed to assign token for lease revoking",
+			zap.Error(err),
+		)
+		return ctx
+	}
+
+	mdMap := map[string]string{
+		rpctypes.TokenFieldNameGRPC: token,
+	}
+	tokenMD := metadata.New(mdMap)
+
+	// use "mdIncomingKey{}" since it's called from local etcdserver
+	return metadata.NewIncomingContext(ctx, tokenMD)
+}
+
+func (as *authStore) HasRole(user, role string) bool {
+	tx := as.be.BatchTx()
+	tx.Lock()
+	u := tx.UnsafeGetUser(user)
+	tx.Unlock()
+
+	if u == nil {
+		as.lg.Warn(
+			"'has-role' requested for non-existing user",
+			zap.String("user-name", user),
+			zap.String("role-name", role),
+		)
+		return false
+	}
+
+	for _, r := range u.Roles {
+		if role == r {
+			return true
+		}
+	}
+	return false
+}
+
+func (as *authStore) BcryptCost() int {
+	return as.bcryptCost
+}
+
+func (as *authStore) setupMetricsReporter() {
+	reportCurrentAuthRevMu.Lock()
+	reportCurrentAuthRev = func() float64 {
+		return float64(as.Revision())
+	}
+	reportCurrentAuthRevMu.Unlock()
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/config/config.go b/vendor/go.etcd.io/etcd/server/v3/config/config.go
new file mode 100644
index 0000000..3bf994b
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/config/config.go
@@ -0,0 +1,368 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package config
+
+import (
+	"context"
+	"fmt"
+	"path/filepath"
+	"sort"
+	"strings"
+	"time"
+
+	"go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc"
+	"go.uber.org/zap"
+
+	bolt "go.etcd.io/bbolt"
+	"go.etcd.io/etcd/client/pkg/v3/transport"
+	"go.etcd.io/etcd/client/pkg/v3/types"
+	"go.etcd.io/etcd/pkg/v3/featuregate"
+	"go.etcd.io/etcd/pkg/v3/netutil"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v3discovery"
+	"go.etcd.io/etcd/server/v3/storage/datadir"
+)
+
+const (
+	grpcOverheadBytes = 512 * 1024
+)
+
+// ServerConfig holds the configuration of etcd as taken from the command line or discovery.
+type ServerConfig struct {
+	Name string
+
+	DiscoveryURL   string
+	DiscoveryProxy string
+	DiscoveryCfg   v3discovery.DiscoveryConfig
+
+	ClientURLs types.URLs
+	PeerURLs   types.URLs
+	DataDir    string
+	// DedicatedWALDir config will make the etcd to write the WAL to the WALDir
+	// rather than the dataDir/member/wal.
+	DedicatedWALDir string
+
+	SnapshotCount uint64
+
+	// SnapshotCatchUpEntries is the number of entries for a slow follower
+	// to catch-up after compacting the raft storage entries.
+	// We expect the follower has a millisecond level latency with the leader.
+	// The max throughput is around 10K. Keep a 5K entries is enough for helping
+	// follower to catch up.
+	SnapshotCatchUpEntries uint64
+
+	MaxSnapFiles uint
+	MaxWALFiles  uint
+
+	// BackendBatchInterval is the maximum time before commit the backend transaction.
+	BackendBatchInterval time.Duration
+	// BackendBatchLimit is the maximum operations before commit the backend transaction.
+	BackendBatchLimit int
+
+	// BackendFreelistType is the type of the backend boltdb freelist.
+	BackendFreelistType bolt.FreelistType
+
+	InitialPeerURLsMap  types.URLsMap
+	InitialClusterToken string
+	NewCluster          bool
+	PeerTLSInfo         transport.TLSInfo
+
+	CORS map[string]struct{}
+
+	// HostWhitelist lists acceptable hostnames from client requests.
+	// If server is insecure (no TLS), server only accepts requests
+	// whose Host header value exists in this white list.
+	HostWhitelist map[string]struct{}
+
+	TickMs        uint
+	ElectionTicks int
+
+	// InitialElectionTickAdvance is true, then local member fast-forwards
+	// election ticks to speed up "initial" leader election trigger. This
+	// benefits the case of larger election ticks. For instance, cross
+	// datacenter deployment may require longer election timeout of 10-second.
+	// If true, local node does not need wait up to 10-second. Instead,
+	// forwards its election ticks to 8-second, and have only 2-second left
+	// before leader election.
+	//
+	// Major assumptions are that:
+	//  - cluster has no active leader thus advancing ticks enables faster
+	//    leader election, or
+	//  - cluster already has an established leader, and rejoining follower
+	//    is likely to receive heartbeats from the leader after tick advance
+	//    and before election timeout.
+	//
+	// However, when network from leader to rejoining follower is congested,
+	// and the follower does not receive leader heartbeat within left election
+	// ticks, disruptive election has to happen thus affecting cluster
+	// availabilities.
+	//
+	// Disabling this would slow down initial bootstrap process for cross
+	// datacenter deployments. Make your own tradeoffs by configuring
+	// --initial-election-tick-advance at the cost of slow initial bootstrap.
+	//
+	// If single-node, it advances ticks regardless.
+	//
+	// See https://github.com/etcd-io/etcd/issues/9333 for more detail.
+	InitialElectionTickAdvance bool
+
+	BootstrapTimeout time.Duration
+
+	AutoCompactionRetention time.Duration
+	AutoCompactionMode      string
+	CompactionBatchLimit    int
+	CompactionSleepInterval time.Duration
+	QuotaBackendBytes       int64
+	MaxTxnOps               uint
+
+	// MaxRequestBytes is the maximum request size to send over raft.
+	MaxRequestBytes uint
+
+	// MaxConcurrentStreams specifies the maximum number of concurrent
+	// streams that each client can open at a time.
+	MaxConcurrentStreams uint32
+
+	WarningApplyDuration        time.Duration
+	WarningUnaryRequestDuration time.Duration
+
+	StrictReconfigCheck bool
+
+	// ClientCertAuthEnabled is true when cert has been signed by the client CA.
+	ClientCertAuthEnabled bool
+
+	AuthToken  string
+	BcryptCost uint
+	TokenTTL   uint
+
+	// InitialCorruptCheck is true to check data corruption on boot
+	// before serving any peer/client traffic.
+	InitialCorruptCheck  bool
+	CorruptCheckTime     time.Duration
+	CompactHashCheckTime time.Duration
+
+	// PreVote is true to enable Raft Pre-Vote.
+	PreVote bool
+
+	// SocketOpts are socket options passed to listener config.
+	SocketOpts transport.SocketOpts
+
+	// Logger logs server-side operations.
+	Logger *zap.Logger
+
+	ForceNewCluster bool
+
+	// LeaseCheckpointInterval time.Duration is the wait duration between lease checkpoints.
+	LeaseCheckpointInterval time.Duration
+
+	EnableGRPCGateway bool
+
+	// EnableDistributedTracing enables distributed tracing using OpenTelemetry protocol.
+	EnableDistributedTracing bool
+	// TracerOptions are options for OpenTelemetry gRPC interceptor.
+	TracerOptions []otelgrpc.Option
+
+	WatchProgressNotifyInterval time.Duration
+
+	// UnsafeNoFsync disables all uses of fsync.
+	// Setting this is unsafe and will cause data loss.
+	UnsafeNoFsync bool `json:"unsafe-no-fsync"`
+
+	DowngradeCheckTime time.Duration
+
+	// MemoryMlock enables mlocking of etcd owned memory pages.
+	// The setting improves etcd tail latency in environments were:
+	//   - memory pressure might lead to swapping pages to disk
+	//   - disk latency might be unstable
+	// Currently all etcd memory gets mlocked, but in future the flag can
+	// be refined to mlock in-use area of bbolt only.
+	MemoryMlock bool `json:"memory-mlock"`
+
+	// ExperimentalTxnModeWriteWithSharedBuffer enable write transaction to use
+	// a shared buffer in its readonly check operations.
+	// TODO: Delete in v3.7
+	// Deprecated: Use TxnModeWriteWithSharedBuffer Feature Gate instead. Will be decommissioned in v3.7.
+	ExperimentalTxnModeWriteWithSharedBuffer bool `json:"experimental-txn-mode-write-with-shared-buffer"`
+
+	// BootstrapDefragThresholdMegabytes is the minimum number of megabytes needed to be freed for etcd server to
+	// consider running defrag during bootstrap. Needs to be set to non-zero value to take effect.
+	BootstrapDefragThresholdMegabytes uint `json:"bootstrap-defrag-threshold-megabytes"`
+
+	// MaxLearners sets a limit to the number of learner members that can exist in the cluster membership.
+	MaxLearners int `json:"max-learners"`
+
+	// V2Deprecation defines a phase of v2store deprecation process.
+	V2Deprecation V2DeprecationEnum `json:"v2-deprecation"`
+
+	// ExperimentalLocalAddress is the local IP address to use when communicating with a peer.
+	ExperimentalLocalAddress string `json:"experimental-local-address"`
+
+	// ServerFeatureGate is a server level feature gate
+	ServerFeatureGate featuregate.FeatureGate
+
+	// Metrics types of metrics - should be either 'basic' or 'extensive'
+	Metrics string
+}
+
+// VerifyBootstrap sanity-checks the initial config for bootstrap case
+// and returns an error for things that should never happen.
+func (c *ServerConfig) VerifyBootstrap() error {
+	if err := c.hasLocalMember(); err != nil {
+		return err
+	}
+	if err := c.advertiseMatchesCluster(); err != nil {
+		return err
+	}
+	if CheckDuplicateURL(c.InitialPeerURLsMap) {
+		return fmt.Errorf("initial cluster %s has duplicate url", c.InitialPeerURLsMap)
+	}
+	if c.InitialPeerURLsMap.String() == "" && c.DiscoveryURL == "" {
+		return fmt.Errorf("initial cluster unset and no discovery URL found")
+	}
+	return nil
+}
+
+// VerifyJoinExisting sanity-checks the initial config for join existing cluster
+// case and returns an error for things that should never happen.
+func (c *ServerConfig) VerifyJoinExisting() error {
+	// The member has announced its peer urls to the cluster before starting; no need to
+	// set the configuration again.
+	if err := c.hasLocalMember(); err != nil {
+		return err
+	}
+	if CheckDuplicateURL(c.InitialPeerURLsMap) {
+		return fmt.Errorf("initial cluster %s has duplicate url", c.InitialPeerURLsMap)
+	}
+	if c.DiscoveryURL != "" {
+		return fmt.Errorf("discovery URL should not be set when joining existing initial cluster")
+	}
+	return nil
+}
+
+// hasLocalMember checks that the cluster at least contains the local server.
+func (c *ServerConfig) hasLocalMember() error {
+	if urls := c.InitialPeerURLsMap[c.Name]; urls == nil {
+		return fmt.Errorf("couldn't find local name %q in the initial cluster configuration", c.Name)
+	}
+	return nil
+}
+
+// advertiseMatchesCluster confirms peer URLs match those in the cluster peer list.
+func (c *ServerConfig) advertiseMatchesCluster() error {
+	urls, apurls := c.InitialPeerURLsMap[c.Name], c.PeerURLs.StringSlice()
+	urls.Sort()
+	sort.Strings(apurls)
+	ctx, cancel := context.WithTimeout(context.TODO(), 30*time.Second)
+	defer cancel()
+	ok, err := netutil.URLStringsEqual(ctx, c.Logger, apurls, urls.StringSlice())
+	if ok {
+		return nil
+	}
+
+	initMap, apMap := make(map[string]struct{}), make(map[string]struct{})
+	for _, url := range c.PeerURLs {
+		apMap[url.String()] = struct{}{}
+	}
+	for _, url := range c.InitialPeerURLsMap[c.Name] {
+		initMap[url.String()] = struct{}{}
+	}
+
+	var missing []string
+	for url := range initMap {
+		if _, ok := apMap[url]; !ok {
+			missing = append(missing, url)
+		}
+	}
+	if len(missing) > 0 {
+		for i := range missing {
+			missing[i] = c.Name + "=" + missing[i]
+		}
+		mstr := strings.Join(missing, ",")
+		apStr := strings.Join(apurls, ",")
+		return fmt.Errorf("--initial-cluster has %s but missing from --initial-advertise-peer-urls=%s (%w)", mstr, apStr, err)
+	}
+
+	for url := range apMap {
+		if _, ok := initMap[url]; !ok {
+			missing = append(missing, url)
+		}
+	}
+	if len(missing) > 0 {
+		mstr := strings.Join(missing, ",")
+		umap := types.URLsMap(map[string]types.URLs{c.Name: c.PeerURLs})
+		return fmt.Errorf("--initial-advertise-peer-urls has %s but missing from --initial-cluster=%s", mstr, umap.String())
+	}
+
+	// resolved URLs from "--initial-advertise-peer-urls" and "--initial-cluster" did not match or failed
+	apStr := strings.Join(apurls, ",")
+	umap := types.URLsMap(map[string]types.URLs{c.Name: c.PeerURLs})
+	return fmt.Errorf("failed to resolve %s to match --initial-cluster=%s (%w)", apStr, umap.String(), err)
+}
+
+func (c *ServerConfig) MemberDir() string { return datadir.ToMemberDir(c.DataDir) }
+
+func (c *ServerConfig) WALDir() string {
+	if c.DedicatedWALDir != "" {
+		return c.DedicatedWALDir
+	}
+	return datadir.ToWALDir(c.DataDir)
+}
+
+func (c *ServerConfig) SnapDir() string { return filepath.Join(c.MemberDir(), "snap") }
+
+func (c *ServerConfig) ShouldDiscover() bool {
+	return c.DiscoveryURL != "" || len(c.DiscoveryCfg.Endpoints) > 0
+}
+
+// ReqTimeout returns timeout for request to finish.
+func (c *ServerConfig) ReqTimeout() time.Duration {
+	// 5s for queue waiting, computation and disk IO delay
+	// + 2 * election timeout for possible leader election
+	return 5*time.Second + 2*time.Duration(c.ElectionTicks*int(c.TickMs))*time.Millisecond
+}
+
+func (c *ServerConfig) ElectionTimeout() time.Duration {
+	return time.Duration(c.ElectionTicks*int(c.TickMs)) * time.Millisecond
+}
+
+func (c *ServerConfig) PeerDialTimeout() time.Duration {
+	// 1s for queue wait and election timeout
+	return time.Second + time.Duration(c.ElectionTicks*int(c.TickMs))*time.Millisecond
+}
+
+func CheckDuplicateURL(urlsmap types.URLsMap) bool {
+	um := make(map[string]bool)
+	for _, urls := range urlsmap {
+		for _, url := range urls {
+			u := url.String()
+			if um[u] {
+				return true
+			}
+			um[u] = true
+		}
+	}
+	return false
+}
+
+func (c *ServerConfig) BootstrapTimeoutEffective() time.Duration {
+	if c.BootstrapTimeout != 0 {
+		return c.BootstrapTimeout
+	}
+	return time.Second
+}
+
+func (c *ServerConfig) BackendPath() string { return datadir.ToBackendFileName(c.DataDir) }
+
+func (c *ServerConfig) MaxRequestBytesWithOverhead() uint {
+	return c.MaxRequestBytes + grpcOverheadBytes
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/config/v2_deprecation.go b/vendor/go.etcd.io/etcd/server/v3/config/v2_deprecation.go
new file mode 100644
index 0000000..c50401c
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/config/v2_deprecation.go
@@ -0,0 +1,84 @@
+// Copyright 2021 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package config
+
+type V2DeprecationEnum string
+
+const (
+	// V2Depr0NotYet means v2store isn't deprecated yet.
+	// Default in v3.5, and no longer supported in v3.6.
+	V2Depr0NotYet = V2DeprecationEnum("not-yet")
+
+	// Deprecated: to be decommissioned in 3.7. Please use V2Depr0NotYet.
+	// TODO: remove in 3.7
+	//revive:disable-next-line:var-naming
+	V2_DEPR_0_NOT_YET = V2Depr0NotYet
+
+	// V2Depr1WriteOnly means only writing v2store is allowed.
+	// Default in v3.6.  Meaningful v2 state is not allowed.
+	// The V2 files are maintained for v3.5 rollback.
+	V2Depr1WriteOnly = V2DeprecationEnum("write-only")
+
+	// Deprecated: to be decommissioned in 3.7. Please use V2Depr1WriteOnly.
+	// TODO: remove in 3.7
+	//revive:disable-next-line:var-naming
+	V2_DEPR_1_WRITE_ONLY = V2Depr1WriteOnly
+
+	// V2Depr1WriteOnlyDrop means v2store is WIPED if found !!!
+	// Will be default in 3.7.
+	V2Depr1WriteOnlyDrop = V2DeprecationEnum("write-only-drop-data")
+
+	// Deprecated: to be decommissioned in 3.7. Pleae use V2Depr1WriteOnlyDrop.
+	// TODO: remove in 3.7
+	//revive:disable-next-line:var-naming
+	V2_DEPR_1_WRITE_ONLY_DROP = V2Depr1WriteOnlyDrop
+
+	// V2Depr2Gone means v2store is completely gone. The v2store is
+	// neither written nor read. Anything related to v2store will be
+	// cleaned up in v3.8. Usage of this configuration is blocking
+	// ability to rollback to etcd v3.5.
+	V2Depr2Gone = V2DeprecationEnum("gone")
+
+	// Deprecated: to be decommissioned in 3.7. Please use V2Depr2Gone.
+	// TODO: remove in 3.7
+	//revive:disable-next-line:var-naming
+	V2_DEPR_2_GONE = V2Depr2Gone
+
+	// V2DeprDefault is the default deprecation level.
+	V2DeprDefault = V2Depr1WriteOnly
+
+	// Deprecated: to be decommissioned in 3.7. Please use V2DeprDefault.
+	// TODO: remove in 3.7
+	//revive:disable-next-line:var-naming
+	V2_DEPR_DEFAULT = V2DeprDefault
+)
+
+func (e V2DeprecationEnum) IsAtLeast(v2d V2DeprecationEnum) bool {
+	return e.level() >= v2d.level()
+}
+
+func (e V2DeprecationEnum) level() int {
+	switch e {
+	case V2Depr0NotYet:
+		return 0
+	case V2Depr1WriteOnly:
+		return 1
+	case V2Depr1WriteOnlyDrop:
+		return 2
+	case V2Depr2Gone:
+		return 3
+	}
+	panic("Unknown V2DeprecationEnum: " + e)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/embed/config.go b/vendor/go.etcd.io/etcd/server/v3/embed/config.go
new file mode 100644
index 0000000..8f4a6aa
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/embed/config.go
@@ -0,0 +1,1678 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package embed
+
+import (
+	"crypto/tls"
+	"errors"
+	"flag"
+	"fmt"
+	"math"
+	"net"
+	"net/http"
+	"net/netip"
+	"net/url"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+	"time"
+
+	"go.uber.org/zap"
+	"golang.org/x/crypto/bcrypt"
+	"google.golang.org/grpc"
+	"sigs.k8s.io/yaml"
+
+	bolt "go.etcd.io/bbolt"
+	"go.etcd.io/etcd/client/pkg/v3/logutil"
+	"go.etcd.io/etcd/client/pkg/v3/srv"
+	"go.etcd.io/etcd/client/pkg/v3/tlsutil"
+	"go.etcd.io/etcd/client/pkg/v3/transport"
+	"go.etcd.io/etcd/client/pkg/v3/types"
+	clientv3 "go.etcd.io/etcd/client/v3"
+	"go.etcd.io/etcd/pkg/v3/featuregate"
+	"go.etcd.io/etcd/pkg/v3/flags"
+	"go.etcd.io/etcd/pkg/v3/netutil"
+	"go.etcd.io/etcd/server/v3/config"
+	"go.etcd.io/etcd/server/v3/etcdserver"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/membership"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v3compactor"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v3discovery"
+	"go.etcd.io/etcd/server/v3/features"
+)
+
+const (
+	ClusterStateFlagNew      = "new"
+	ClusterStateFlagExisting = "existing"
+
+	DefaultName                        = "default"
+	DefaultMaxSnapshots                = 5
+	DefaultMaxWALs                     = 5
+	DefaultMaxTxnOps                   = uint(128)
+	DefaultWarningApplyDuration        = 100 * time.Millisecond
+	DefaultWarningUnaryRequestDuration = 300 * time.Millisecond
+	DefaultMaxRequestBytes             = 1.5 * 1024 * 1024
+	DefaultMaxConcurrentStreams        = math.MaxUint32
+	DefaultGRPCKeepAliveMinTime        = 5 * time.Second
+	DefaultGRPCKeepAliveInterval       = 2 * time.Hour
+	DefaultGRPCKeepAliveTimeout        = 20 * time.Second
+	DefaultDowngradeCheckTime          = 5 * time.Second
+	DefaultAutoCompactionMode          = "periodic"
+	DefaultAutoCompactionRetention     = "0"
+	DefaultAuthToken                   = "simple"
+	DefaultCompactHashCheckTime        = time.Minute
+	DefaultLoggingFormat               = "json"
+
+	DefaultDiscoveryDialTimeout       = 2 * time.Second
+	DefaultDiscoveryRequestTimeOut    = 5 * time.Second
+	DefaultDiscoveryKeepAliveTime     = 2 * time.Second
+	DefaultDiscoveryKeepAliveTimeOut  = 6 * time.Second
+	DefaultDiscoveryInsecureTransport = true
+	DefaultSelfSignedCertValidity     = 1
+	DefaultTLSMinVersion              = string(tlsutil.TLSVersion12)
+
+	DefaultListenPeerURLs   = "http://localhost:2380"
+	DefaultListenClientURLs = "http://localhost:2379"
+
+	DefaultLogOutput = "default"
+	JournalLogOutput = "systemd/journal"
+	StdErrLogOutput  = "stderr"
+	StdOutLogOutput  = "stdout"
+
+	// DefaultLogRotationConfig is the default configuration used for log rotation.
+	// Log rotation is disabled by default.
+	// MaxSize    = 100 // MB
+	// MaxAge     = 0 // days (no limit)
+	// MaxBackups = 0 // no limit
+	// LocalTime  = false // use computers local time, UTC by default
+	// Compress   = false // compress the rotated log in gzip format
+	DefaultLogRotationConfig = `{"maxsize": 100, "maxage": 0, "maxbackups": 0, "localtime": false, "compress": false}`
+
+	// ExperimentalDistributedTracingAddress is the default collector address.
+	// TODO: delete in v3.7
+	// Deprecated: Use DefaultDistributedTracingAddress instead. Will be decommissioned in v3.7.
+	ExperimentalDistributedTracingAddress = "localhost:4317"
+	// DefaultDistributedTracingAddress is the default collector address.
+	DefaultDistributedTracingAddress = "localhost:4317"
+	// ExperimentalDistributedTracingServiceName is the default etcd service name.
+	// TODO: delete in v3.7
+	// Deprecated: Use DefaultDistributedTracingServiceName instead. Will be decommissioned in v3.7.
+	ExperimentalDistributedTracingServiceName = "etcd"
+	// DefaultDistributedTracingServiceName is the default etcd service name.
+	DefaultDistributedTracingServiceName = "etcd"
+
+	DefaultExperimentalTxnModeWriteWithSharedBuffer = true
+
+	// DefaultStrictReconfigCheck is the default value for "--strict-reconfig-check" flag.
+	// It's enabled by default.
+	DefaultStrictReconfigCheck = true
+
+	// maxElectionMs specifies the maximum value of election timeout.
+	// More details are listed on etcd.io/docs > version > tuning/#time-parameters
+	maxElectionMs = 50000
+	// backend freelist map type
+	freelistArrayType = "array"
+
+	ServerFeatureGateFlagName = "feature-gates"
+)
+
+var (
+	ErrConflictBootstrapFlags = fmt.Errorf("multiple discovery or bootstrap flags are set. " +
+		"Choose one of \"initial-cluster\", \"discovery\", \"discovery-endpoints\" or \"discovery-srv\"")
+	ErrUnsetAdvertiseClientURLsFlag = fmt.Errorf("--advertise-client-urls is required when --listen-client-urls is set explicitly")
+	ErrLogRotationInvalidLogOutput  = fmt.Errorf("--log-outputs requires a single file path when --log-rotate-config-json is defined")
+
+	DefaultInitialAdvertisePeerURLs = "http://localhost:2380"
+	DefaultAdvertiseClientURLs      = "http://localhost:2379"
+
+	defaultHostname   string
+	defaultHostStatus error
+
+	// indirection for testing
+	getCluster = srv.GetCluster
+
+	// in 3.6, we are migration all the --experimental flags to feature gate and flags without the prefix.
+	// This is the mapping from the non boolean `experimental-` to the new flags.
+	// TODO: delete in v3.7
+	experimentalFlagMigrationMap = map[string]string{
+		"experimental-compact-hash-check-time":              "compact-hash-check-time",
+		"experimental-corrupt-check-time":                   "corrupt-check-time",
+		"experimental-compaction-batch-limit":               "compaction-batch-limit",
+		"experimental-watch-progress-notify-interval":       "watch-progress-notify-interval",
+		"experimental-warning-apply-duration":               "warning-apply-duration",
+		"experimental-bootstrap-defrag-threshold-megabytes": "bootstrap-defrag-threshold-megabytes",
+		"experimental-memory-mlock":                         "memory-mlock",
+		"experimental-snapshot-catchup-entries":             "snapshot-catchup-entries",
+		"experimental-compaction-sleep-interval":            "compaction-sleep-interval",
+		"experimental-downgrade-check-time":                 "downgrade-check-time",
+		"experimental-peer-skip-client-san-verification":    "peer-skip-client-san-verification",
+		"experimental-enable-distributed-tracing":           "enable-distributed-tracing",
+		"experimental-distributed-tracing-address":          "distributed-tracing-address",
+		"experimental-distributed-tracing-service-name":     "distributed-tracing-service-name",
+		"experimental-distributed-tracing-instance-id":      "distributed-tracing-instance-id",
+		"experimental-distributed-tracing-sampling-rate":    "distributed-tracing-sampling-rate",
+	}
+)
+
+var (
+	// CompactorModePeriodic is periodic compaction mode
+	// for "Config.AutoCompactionMode" field.
+	// If "AutoCompactionMode" is CompactorModePeriodic and
+	// "AutoCompactionRetention" is "1h", it automatically compacts
+	// compacts storage every hour.
+	CompactorModePeriodic = v3compactor.ModePeriodic
+
+	// CompactorModeRevision is revision-based compaction mode
+	// for "Config.AutoCompactionMode" field.
+	// If "AutoCompactionMode" is CompactorModeRevision and
+	// "AutoCompactionRetention" is "1000", it compacts log on
+	// revision 5000 when the current revision is 6000.
+	// This runs every 5-minute if enough of logs have proceeded.
+	CompactorModeRevision = v3compactor.ModeRevision
+)
+
+func init() {
+	defaultHostname, defaultHostStatus = netutil.GetDefaultHost()
+}
+
+// Config holds the arguments for configuring an etcd server.
+type Config struct {
+	Name string `json:"name"`
+	Dir  string `json:"data-dir"`
+	//revive:disable-next-line:var-naming
+	WalDir string `json:"wal-dir"`
+
+	// SnapshotCount is the number of committed transactions that trigger a snapshot to disk.
+	// TODO: remove it in 3.7.
+	// Deprecated: Will be decommissioned in v3.7.
+	SnapshotCount uint64 `json:"snapshot-count"`
+
+	// ExperimentalSnapshotCatchUpEntries is the number of entries for a slow follower
+	// to catch-up after compacting the raft storage entries.
+	// We expect the follower has a millisecond level latency with the leader.
+	// The max throughput is around 10K. Keep a 5K entries is enough for helping
+	// follower to catch up.
+	// TODO: remove in v3.7.
+	// Note we made a mistake in https://github.com/etcd-io/etcd/pull/15033. The json tag
+	// `*-catch-up-*` isn't consistent with the command line flag `*-catchup-*`.
+	// Deprecated: Use SnapshotCatchUpEntries instead. Will be removed in v3.7.
+	ExperimentalSnapshotCatchUpEntries uint64 `json:"experimental-snapshot-catch-up-entries"`
+
+	// SnapshotCatchUpEntries is the number of entires for a slow follower
+	// to catch-up after compacting the raft storage entries.
+	// We expect the follower has a millisecond level latency with the leader.
+	// The max throughput is around 10K. Keep a 5K entries is enough for helping
+	// follower to catch up.
+	SnapshotCatchUpEntries uint64 `json:"snapshot-catchup-entries"`
+
+	// MaxSnapFiles is the maximum number of snapshot files.
+	// TODO: remove it in 3.7.
+	// Deprecated: Will be removed in v3.7.
+	MaxSnapFiles uint `json:"max-snapshots"`
+	//revive:disable-next-line:var-naming
+	MaxWalFiles uint `json:"max-wals"`
+
+	// TickMs is the number of milliseconds between heartbeat ticks.
+	// TODO: decouple tickMs and heartbeat tick (current heartbeat tick = 1).
+	// make ticks a cluster wide configuration.
+	TickMs     uint `json:"heartbeat-interval"`
+	ElectionMs uint `json:"election-timeout"`
+
+	// InitialElectionTickAdvance is true, then local member fast-forwards
+	// election ticks to speed up "initial" leader election trigger. This
+	// benefits the case of larger election ticks. For instance, cross
+	// datacenter deployment may require longer election timeout of 10-second.
+	// If true, local node does not need wait up to 10-second. Instead,
+	// forwards its election ticks to 8-second, and have only 2-second left
+	// before leader election.
+	//
+	// Major assumptions are that:
+	//  - cluster has no active leader thus advancing ticks enables faster
+	//    leader election, or
+	//  - cluster already has an established leader, and rejoining follower
+	//    is likely to receive heartbeats from the leader after tick advance
+	//    and before election timeout.
+	//
+	// However, when network from leader to rejoining follower is congested,
+	// and the follower does not receive leader heartbeat within left election
+	// ticks, disruptive election has to happen thus affecting cluster
+	// availabilities.
+	//
+	// Disabling this would slow down initial bootstrap process for cross
+	// datacenter deployments. Make your own tradeoffs by configuring
+	// --initial-election-tick-advance at the cost of slow initial bootstrap.
+	//
+	// If single-node, it advances ticks regardless.
+	//
+	// See https://github.com/etcd-io/etcd/issues/9333 for more detail.
+	InitialElectionTickAdvance bool `json:"initial-election-tick-advance"`
+
+	// BackendBatchInterval is the maximum time before commit the backend transaction.
+	BackendBatchInterval time.Duration `json:"backend-batch-interval"`
+	// BackendBatchLimit is the maximum operations before commit the backend transaction.
+	BackendBatchLimit int `json:"backend-batch-limit"`
+	// BackendFreelistType specifies the type of freelist that boltdb backend uses (array and map are supported types).
+	BackendFreelistType string `json:"backend-bbolt-freelist-type"`
+	QuotaBackendBytes   int64  `json:"quota-backend-bytes"`
+	MaxTxnOps           uint   `json:"max-txn-ops"`
+	MaxRequestBytes     uint   `json:"max-request-bytes"`
+
+	// MaxConcurrentStreams specifies the maximum number of concurrent
+	// streams that each client can open at a time.
+	MaxConcurrentStreams uint32 `json:"max-concurrent-streams"`
+
+	//revive:disable:var-naming
+	ListenPeerUrls, ListenClientUrls, ListenClientHttpUrls []url.URL
+	AdvertisePeerUrls, AdvertiseClientUrls                 []url.URL
+	//revive:enable:var-naming
+
+	ClientTLSInfo transport.TLSInfo
+	ClientAutoTLS bool
+	PeerTLSInfo   transport.TLSInfo
+	PeerAutoTLS   bool
+
+	// SelfSignedCertValidity specifies the validity period of the client and peer certificates
+	// that are automatically generated by etcd when you specify ClientAutoTLS and PeerAutoTLS,
+	// the unit is year, and the default is 1
+	SelfSignedCertValidity uint `json:"self-signed-cert-validity"`
+
+	// CipherSuites is a list of supported TLS cipher suites between
+	// client/server and peers. If empty, Go auto-populates the list.
+	// Note that cipher suites are prioritized in the given order.
+	CipherSuites []string `json:"cipher-suites"`
+
+	// TlsMinVersion is the minimum accepted TLS version between client/server and peers.
+	//revive:disable-next-line:var-naming
+	TlsMinVersion string `json:"tls-min-version"`
+
+	// TlsMaxVersion is the maximum accepted TLS version between client/server and peers.
+	//revive:disable-next-line:var-naming
+	TlsMaxVersion string `json:"tls-max-version"`
+
+	ClusterState          string `json:"initial-cluster-state"`
+	DNSCluster            string `json:"discovery-srv"`
+	DNSClusterServiceName string `json:"discovery-srv-name"`
+	Dproxy                string `json:"discovery-proxy"`
+
+	Durl         string                      `json:"discovery"`
+	DiscoveryCfg v3discovery.DiscoveryConfig `json:"discovery-config"`
+
+	InitialCluster      string `json:"initial-cluster"`
+	InitialClusterToken string `json:"initial-cluster-token"`
+	StrictReconfigCheck bool   `json:"strict-reconfig-check"`
+
+	// AutoCompactionMode is either 'periodic' or 'revision'.
+	AutoCompactionMode string `json:"auto-compaction-mode"`
+	// AutoCompactionRetention is either duration string with time unit
+	// (e.g. '5m' for 5-minute), or revision unit (e.g. '5000').
+	// If no time unit is provided and compaction mode is 'periodic',
+	// the unit defaults to hour. For example, '5' translates into 5-hour.
+	AutoCompactionRetention string `json:"auto-compaction-retention"`
+
+	// GRPCKeepAliveMinTime is the minimum interval that a client should
+	// wait before pinging server. When client pings "too fast", server
+	// sends goaway and closes the connection (errors: too_many_pings,
+	// http2.ErrCodeEnhanceYourCalm). When too slow, nothing happens.
+	// Server expects client pings only when there is any active streams
+	// (PermitWithoutStream is set false).
+	GRPCKeepAliveMinTime time.Duration `json:"grpc-keepalive-min-time"`
+	// GRPCKeepAliveInterval is the frequency of server-to-client ping
+	// to check if a connection is alive. Close a non-responsive connection
+	// after an additional duration of Timeout. 0 to disable.
+	GRPCKeepAliveInterval time.Duration `json:"grpc-keepalive-interval"`
+	// GRPCKeepAliveTimeout is the additional duration of wait
+	// before closing a non-responsive connection. 0 to disable.
+	GRPCKeepAliveTimeout time.Duration `json:"grpc-keepalive-timeout"`
+
+	// GRPCAdditionalServerOptions is the additional server option hook
+	// for changing the default internal gRPC configuration. Note these
+	// additional configurations take precedence over the existing individual
+	// configurations if present. Please refer to
+	// https://github.com/etcd-io/etcd/pull/14066#issuecomment-1248682996
+	GRPCAdditionalServerOptions []grpc.ServerOption `json:"grpc-additional-server-options"`
+
+	// SocketOpts are socket options passed to listener config.
+	SocketOpts transport.SocketOpts `json:"socket-options"`
+
+	// PreVote is true to enable Raft Pre-Vote.
+	// If enabled, Raft runs an additional election phase
+	// to check whether it would get enough votes to win
+	// an election, thus minimizing disruptions.
+	PreVote bool `json:"pre-vote"`
+
+	CORS map[string]struct{}
+
+	// HostWhitelist lists acceptable hostnames from HTTP client requests.
+	// Client origin policy protects against "DNS Rebinding" attacks
+	// to insecure etcd servers. That is, any website can simply create
+	// an authorized DNS name, and direct DNS to "localhost" (or any
+	// other address). Then, all HTTP endpoints of etcd server listening
+	// on "localhost" becomes accessible, thus vulnerable to DNS rebinding
+	// attacks. See "CVE-2018-5702" for more detail.
+	//
+	// 1. If client connection is secure via HTTPS, allow any hostnames.
+	// 2. If client connection is not secure and "HostWhitelist" is not empty,
+	//    only allow HTTP requests whose Host field is listed in whitelist.
+	//
+	// Note that the client origin policy is enforced whether authentication
+	// is enabled or not, for tighter controls.
+	//
+	// By default, "HostWhitelist" is "*", which allows any hostnames.
+	// Note that when specifying hostnames, loopback addresses are not added
+	// automatically. To allow loopback interfaces, leave it empty or set it "*",
+	// or add them to whitelist manually (e.g. "localhost", "127.0.0.1", etc.).
+	//
+	// CVE-2018-5702 reference:
+	// - https://bugs.chromium.org/p/project-zero/issues/detail?id=1447#c2
+	// - https://github.com/transmission/transmission/pull/468
+	// - https://github.com/etcd-io/etcd/issues/9353
+	HostWhitelist map[string]struct{}
+
+	// UserHandlers is for registering users handlers and only used for
+	// embedding etcd into other applications.
+	// The map key is the route path for the handler, and
+	// you must ensure it can't be conflicted with etcd's.
+	UserHandlers map[string]http.Handler `json:"-"`
+	// ServiceRegister is for registering users' gRPC services. A simple usage example:
+	//	cfg := embed.NewConfig()
+	//	cfg.ServiceRegister = func(s *grpc.Server) {
+	//		pb.RegisterFooServer(s, &fooServer{})
+	//		pb.RegisterBarServer(s, &barServer{})
+	//	}
+	//	embed.StartEtcd(cfg)
+	ServiceRegister func(*grpc.Server) `json:"-"`
+
+	AuthToken  string `json:"auth-token"`
+	BcryptCost uint   `json:"bcrypt-cost"`
+
+	// AuthTokenTTL in seconds of the simple token
+	AuthTokenTTL uint `json:"auth-token-ttl"`
+
+	// ExperimentalInitialCorruptCheck defines to check data corrution on boot.
+	// TODO: delete in v3.7
+	// Deprecated: Use InitialCorruptCheck Feature Gate instead. Will be decommissioned in v3.7.
+	ExperimentalInitialCorruptCheck bool `json:"experimental-initial-corrupt-check"`
+	// ExperimentalCorruptCheckTime is the duration of time between cluster corruption check passes.
+	// TODO: delete in v3.7
+	// Deprecated: Use CorruptCheckTime instead. Will be decommissioned in v3.7.
+	ExperimentalCorruptCheckTime time.Duration `json:"experimental-corrupt-check-time"`
+	// CorruptCheckTime is the duration of time between cluster corruption check passes.
+	CorruptCheckTime time.Duration `json:"corrupt-check-time"`
+	// ExperimentalCompactHashCheckEnabled enables leader to periodically check followers compaction hashes.
+	// TODO: delete in v3.7
+	// Deprecated: Use CompactHashCheck Feature Gate. Will be decommissioned in v3.7.
+	ExperimentalCompactHashCheckEnabled bool `json:"experimental-compact-hash-check-enabled"`
+	// ExperimentalCompactHashCheckTime is the duration of time between leader checks followers compaction hashes.
+	// TODO: delete in v3.7
+	// Deprecated: Use CompactHashCheckTime instead. Will be decommissioned in v3.7.
+	ExperimentalCompactHashCheckTime time.Duration `json:"experimental-compact-hash-check-time"`
+	// CompactHashCheckTime is the duration of time between leader checks followers compaction hashes.
+	CompactHashCheckTime time.Duration `json:"compact-hash-check-time"`
+
+	// ExperimentalEnableLeaseCheckpoint enables leader to send regular checkpoints to other members to prevent reset of remaining TTL on leader change.
+	ExperimentalEnableLeaseCheckpoint bool `json:"experimental-enable-lease-checkpoint"`
+	// ExperimentalEnableLeaseCheckpointPersist enables persisting remainingTTL to prevent indefinite auto-renewal of long lived leases. Always enabled in v3.6. Should be used to ensure smooth upgrade from v3.5 clusters with this feature enabled.
+	// Requires experimental-enable-lease-checkpoint to be enabled.
+	// TODO: Delete in v3.7
+	// Deprecated: To be decommissioned in v3.7.
+	ExperimentalEnableLeaseCheckpointPersist bool `json:"experimental-enable-lease-checkpoint-persist"`
+	// ExperimentalCompactionBatchLimit Sets the maximum revisions deleted in each compaction batch.
+	// TODO: Delete in v3.7
+	// Deprecated: Use CompactionBatchLimit instead. Will be decommissioned in v3.7.
+	ExperimentalCompactionBatchLimit int `json:"experimental-compaction-batch-limit"`
+	// CompactionBatchLimit Sets the maximum revisions deleted in each compaction batch.
+	CompactionBatchLimit int `json:"compaction-batch-limit"`
+	// ExperimentalCompactionSleepInterval is the sleep interval between every etcd compaction loop.
+	// TODO: Delete in v3.7
+	// Deprecated: Use CompactionSleepInterval instead. Will be decommissioned in v3.7.
+	ExperimentalCompactionSleepInterval time.Duration `json:"experimental-compaction-sleep-interval"`
+	// CompactionSleepInterval is the sleep interval between every etcd compaction loop.
+	CompactionSleepInterval time.Duration `json:"compaction-sleep-interval"`
+	// ExperimentalWatchProgressNotifyInterval is the time duration of periodic watch progress notifications.
+	// TODO: Delete in v3.7
+	// Deprecated: Use WatchProgressNotifyInterval instead. Will be decommissioned in v3.7.
+	ExperimentalWatchProgressNotifyInterval time.Duration `json:"experimental-watch-progress-notify-interval"`
+	// WatchProgressNotifyInterval is the time duration of periodic watch progress notifications.
+	WatchProgressNotifyInterval time.Duration `json:"watch-progress-notify-interval"`
+	// ExperimentalWarningApplyDuration is the time duration after which a warning is generated if applying request
+	// takes more time than this value.
+	// TODO: Delete in v3.7
+	// Deprecated: Use WarningApplyDuration instead. Will be decommissioned in v3.7.
+	ExperimentalWarningApplyDuration time.Duration `json:"experimental-warning-apply-duration"`
+	// WarningApplyDuration is the time duration after which a warning is generated if applying request
+	WarningApplyDuration time.Duration `json:"warning-apply-duration"`
+	// ExperimentalBootstrapDefragThresholdMegabytes is the minimum number of megabytes needed to be freed for etcd server to
+	// consider running defrag during bootstrap. Needs to be set to non-zero value to take effect.
+	// TODO: Delete in v3.7
+	// Deprecated: Use BootstrapDefragThresholdMegabytes instead. Will be decommissioned in v3.7.
+	ExperimentalBootstrapDefragThresholdMegabytes uint `json:"experimental-bootstrap-defrag-threshold-megabytes"`
+	// BootstrapDefragThresholdMegabytes is the minimum number of megabytes needed to be freed for etcd server to
+	BootstrapDefragThresholdMegabytes uint `json:"bootstrap-defrag-threshold-megabytes"`
+	// WarningUnaryRequestDuration is the time duration after which a warning is generated if applying
+	// unary request takes more time than this value.
+	WarningUnaryRequestDuration time.Duration `json:"warning-unary-request-duration"`
+	// ExperimentalWarningUnaryRequestDuration is the time duration after which a warning is generated if applying
+	// TODO: Delete in v3.7
+	// Deprecated: Use WarningUnaryRequestDuration. Will be decommissioned in v3.7.
+	ExperimentalWarningUnaryRequestDuration time.Duration `json:"experimental-warning-unary-request-duration"`
+	// MaxLearners sets a limit to the number of learner members that can exist in the cluster membership.
+	MaxLearners int `json:"max-learners"`
+
+	// ForceNewCluster starts a new cluster even if previously started; unsafe.
+	ForceNewCluster bool `json:"force-new-cluster"`
+
+	EnablePprof           bool   `json:"enable-pprof"`
+	Metrics               string `json:"metrics"`
+	ListenMetricsUrls     []url.URL
+	ListenMetricsUrlsJSON string `json:"listen-metrics-urls"`
+
+	// ExperimentalEnableDistributedTracing indicates if experimental tracing using OpenTelemetry is enabled.
+	// TODO: delete in v3.7
+	// Deprecated: Use EnableDistributedTracing instead. Will be decommissioned in v3.7.
+	ExperimentalEnableDistributedTracing bool `json:"experimental-enable-distributed-tracing"`
+	// EnableDistributedTracing indicates if tracing using OpenTelemetry is enabled.
+	EnableDistributedTracing bool `json:"enable-distributed-tracing"`
+	// ExperimentalDistributedTracingAddress is the address of the OpenTelemetry Collector.
+	// Can only be set if ExperimentalEnableDistributedTracing is true.
+	// TODO: delete in v3.7
+	// Deprecated: Use DistributedTracingAddress instead. Will be decommissioned in v3.7.
+	ExperimentalDistributedTracingAddress string `json:"experimental-distributed-tracing-address"`
+	// DistributedTracingAddress is the address of the OpenTelemetry Collector.
+	// Can only be set if EnableDistributedTracing is true.
+	DistributedTracingAddress string `json:"distributed-tracing-address"`
+	// ExperimentalDistributedTracingServiceName is the name of the service.
+	// Can only be used if ExperimentalEnableDistributedTracing is true.
+	// TODO: delete in v3.7
+	// Deprecated: Use DistributedTracingServiceName instead. Will be decommissioned in v3.7.
+	ExperimentalDistributedTracingServiceName string `json:"experimental-distributed-tracing-service-name"`
+	// DistributedTracingServiceName is the name of the service.
+	// Can only be used if EnableDistributedTracing is true.
+	DistributedTracingServiceName string `json:"distributed-tracing-service-name"`
+	// ExperimentalDistributedTracingServiceInstanceID is the ID key of the service.
+	// This ID must be unique, as helps to distinguish instances of the same service
+	// that exist at the same time.
+	// Can only be used if ExperimentalEnableDistributedTracing is true.
+	// TODO: delete in v3.7
+	// Deprecated: Use DistributedTracingServiceInstanceID instead. Will be decommissioned in v3.7.
+	ExperimentalDistributedTracingServiceInstanceID string `json:"experimental-distributed-tracing-instance-id"`
+	// DistributedTracingServiceInstanceID is the ID key of the service.
+	// This ID must be unique, as helps to distinguish instances of the same service
+	// that exist at the same time.
+	// Can only be used if EnableDistributedTracing is true.
+	DistributedTracingServiceInstanceID string `json:"distributed-tracing-instance-id"`
+	// ExperimentalDistributedTracingSamplingRatePerMillion is the number of samples to collect per million spans.
+	// Defaults to 0.
+	// TODO: delete in v3.7
+	// Deprecated: Use DistributedTracingSamplingRatePerMillion instead. Will be decommissioned in v3.7.
+	ExperimentalDistributedTracingSamplingRatePerMillion int `json:"experimental-distributed-tracing-sampling-rate"`
+	// DistributedTracingSamplingRatePerMillion is the number of samples to collect per million spans.
+	// Defaults to 0.
+	DistributedTracingSamplingRatePerMillion int `json:"distributed-tracing-sampling-rate"`
+
+	// ExperimentalPeerSkipClientSanVerification determines whether to skip verification of SAN field
+	// in client certificate for peer connections.
+	// TODO: Delete in v3.7
+	// Deprecated: Use `peer-skip-client-san-verification` instead. Will be decommissioned in v3.7.
+	ExperimentalPeerSkipClientSanVerification bool `json:"experimental-peer-skip-client-san-verification"`
+
+	// Logger is logger options: currently only supports "zap".
+	// "capnslog" is removed in v3.5.
+	Logger string `json:"logger"`
+	// LogLevel configures log level. Only supports debug, info, warn, error, panic, or fatal. Default 'info'.
+	LogLevel string `json:"log-level"`
+	// LogFormat set log encoding. Only supports json, console. Default is 'json'.
+	LogFormat string `json:"log-format"`
+	// LogOutputs is either:
+	//  - "default" as os.Stderr,
+	//  - "stderr" as os.Stderr,
+	//  - "stdout" as os.Stdout,
+	//  - file path to append server logs to.
+	// It can be multiple when "Logger" is zap.
+	LogOutputs []string `json:"log-outputs"`
+	// EnableLogRotation enables log rotation of a single LogOutputs file target.
+	EnableLogRotation bool `json:"enable-log-rotation"`
+	// LogRotationConfigJSON is a passthrough allowing a log rotation JSON config to be passed directly.
+	LogRotationConfigJSON string `json:"log-rotation-config-json"`
+	// ZapLoggerBuilder is used to build the zap logger.
+	ZapLoggerBuilder func(*Config) error
+
+	// logger logs server-side operations. The default is nil,
+	// and "setupLogging" must be called before starting server.
+	// Do not set logger directly.
+	loggerMu *sync.RWMutex
+	logger   *zap.Logger
+	// EnableGRPCGateway enables grpc gateway.
+	// The gateway translates a RESTful HTTP API into gRPC.
+	EnableGRPCGateway bool `json:"enable-grpc-gateway"`
+
+	// UnsafeNoFsync disables all uses of fsync.
+	// Setting this is unsafe and will cause data loss.
+	UnsafeNoFsync bool `json:"unsafe-no-fsync"`
+
+	// ExperimentalDowngradeCheckTime is the duration between two downgrade status checks (in seconds).
+	// TODO: Delete `ExperimentalDowngradeCheckTime` in v3.7.
+	// Deprecated: Use DowngradeCheckTime instead. Will be decommissioned in v3.7.
+	ExperimentalDowngradeCheckTime time.Duration `json:"experimental-downgrade-check-time"`
+	// DowngradeCheckTime is the duration between two downgrade status checks (in seconds).
+	DowngradeCheckTime time.Duration `json:"downgrade-check-time"`
+
+	// MemoryMlock enables mlocking of etcd owned memory pages.
+	// The setting improves etcd tail latency in environments were:
+	//   - memory pressure might lead to swapping pages to disk
+	//   - disk latency might be unstable
+	// Currently all etcd memory gets mlocked, but in future the flag can
+	// be refined to mlock in-use area of bbolt only.
+	MemoryMlock bool `json:"memory-mlock"`
+
+	// ExperimentalMemoryMlock enables mlocking of etcd owned memory pages.
+	// TODO: Delete in v3.7
+	// Deprecated: Use MemoryMlock instad. To be decommissioned in v3.7.
+	ExperimentalMemoryMlock bool `json:"experimental-memory-mlock"`
+
+	// ExperimentalTxnModeWriteWithSharedBuffer enables write transaction to use a shared buffer in its readonly check operations.
+	// TODO: Delete in v3.7
+	// Deprecated: Use TxnModeWriteWithSharedBuffer Feature Flag. Will be decommissioned in v3.7.
+	ExperimentalTxnModeWriteWithSharedBuffer bool `json:"experimental-txn-mode-write-with-shared-buffer"`
+
+	// ExperimentalStopGRPCServiceOnDefrag enables etcd gRPC service to stop serving client requests on defragmentation.
+	// TODO: Delete in v3.7
+	// Deprecated: Use StopGRPCServiceOnDefrag Feature Flag. Will be decommissioned in v3.7.
+	ExperimentalStopGRPCServiceOnDefrag bool `json:"experimental-stop-grpc-service-on-defrag"`
+
+	// V2Deprecation describes phase of API & Storage V2 support.
+	// Do not set this field for embedded use cases, as it has no effect. However, setting it will not cause any harm.
+	// TODO: Delete in v3.8
+	// Deprecated: The default value is enforced, to be removed in v3.8.
+	V2Deprecation config.V2DeprecationEnum `json:"v2-deprecation"`
+
+	// ServerFeatureGate is a server level feature gate
+	ServerFeatureGate featuregate.FeatureGate
+	// FlagsExplicitlySet stores if a flag is explicitly set from the cmd line or config file.
+	FlagsExplicitlySet map[string]bool
+}
+
+// configYAML holds the config suitable for yaml parsing
+type configYAML struct {
+	Config
+	configJSON
+}
+
+// configJSON has file options that are translated into Config options
+type configJSON struct {
+	ListenPeerURLs       string `json:"listen-peer-urls"`
+	ListenClientURLs     string `json:"listen-client-urls"`
+	ListenClientHTTPURLs string `json:"listen-client-http-urls"`
+	AdvertisePeerURLs    string `json:"initial-advertise-peer-urls"`
+	AdvertiseClientURLs  string `json:"advertise-client-urls"`
+
+	CORSJSON          string `json:"cors"`
+	HostWhitelistJSON string `json:"host-whitelist"`
+
+	ClientSecurityJSON securityConfig `json:"client-transport-security"`
+	PeerSecurityJSON   securityConfig `json:"peer-transport-security"`
+
+	ServerFeatureGatesJSON string `json:"feature-gates"`
+}
+
+type securityConfig struct {
+	CertFile            string   `json:"cert-file"`
+	KeyFile             string   `json:"key-file"`
+	ClientCertFile      string   `json:"client-cert-file"`
+	ClientKeyFile       string   `json:"client-key-file"`
+	CertAuth            bool     `json:"client-cert-auth"`
+	TrustedCAFile       string   `json:"trusted-ca-file"`
+	AutoTLS             bool     `json:"auto-tls"`
+	AllowedCNs          []string `json:"allowed-cn"`
+	AllowedHostnames    []string `json:"allowed-hostname"`
+	SkipClientSANVerify bool     `json:"skip-client-san-verification,omitempty"`
+}
+
+// NewConfig creates a new Config populated with default values.
+func NewConfig() *Config {
+	lpurl, _ := url.Parse(DefaultListenPeerURLs)
+	apurl, _ := url.Parse(DefaultInitialAdvertisePeerURLs)
+	lcurl, _ := url.Parse(DefaultListenClientURLs)
+	acurl, _ := url.Parse(DefaultAdvertiseClientURLs)
+	cfg := &Config{
+		MaxSnapFiles: DefaultMaxSnapshots,
+		MaxWalFiles:  DefaultMaxWALs,
+
+		Name: DefaultName,
+
+		SnapshotCount:                      etcdserver.DefaultSnapshotCount,
+		ExperimentalSnapshotCatchUpEntries: etcdserver.DefaultSnapshotCatchUpEntries,
+		SnapshotCatchUpEntries:             etcdserver.DefaultSnapshotCatchUpEntries,
+
+		MaxTxnOps:            DefaultMaxTxnOps,
+		MaxRequestBytes:      DefaultMaxRequestBytes,
+		MaxConcurrentStreams: DefaultMaxConcurrentStreams,
+		WarningApplyDuration: DefaultWarningApplyDuration,
+
+		GRPCKeepAliveMinTime:  DefaultGRPCKeepAliveMinTime,
+		GRPCKeepAliveInterval: DefaultGRPCKeepAliveInterval,
+		GRPCKeepAliveTimeout:  DefaultGRPCKeepAliveTimeout,
+
+		SocketOpts: transport.SocketOpts{
+			ReusePort:    false,
+			ReuseAddress: false,
+		},
+
+		TickMs:                     100,
+		ElectionMs:                 1000,
+		InitialElectionTickAdvance: true,
+
+		ListenPeerUrls:      []url.URL{*lpurl},
+		ListenClientUrls:    []url.URL{*lcurl},
+		AdvertisePeerUrls:   []url.URL{*apurl},
+		AdvertiseClientUrls: []url.URL{*acurl},
+
+		ClusterState:        ClusterStateFlagNew,
+		InitialClusterToken: "etcd-cluster",
+
+		StrictReconfigCheck: DefaultStrictReconfigCheck,
+		Metrics:             "basic",
+
+		CORS:          map[string]struct{}{"*": {}},
+		HostWhitelist: map[string]struct{}{"*": {}},
+
+		AuthToken:              DefaultAuthToken,
+		BcryptCost:             uint(bcrypt.DefaultCost),
+		AuthTokenTTL:           300,
+		SelfSignedCertValidity: DefaultSelfSignedCertValidity,
+		TlsMinVersion:          DefaultTLSMinVersion,
+
+		PreVote: true,
+
+		loggerMu:              new(sync.RWMutex),
+		logger:                nil,
+		Logger:                "zap",
+		LogFormat:             DefaultLoggingFormat,
+		LogOutputs:            []string{DefaultLogOutput},
+		LogLevel:              logutil.DefaultLogLevel,
+		EnableLogRotation:     false,
+		LogRotationConfigJSON: DefaultLogRotationConfig,
+		EnableGRPCGateway:     true,
+
+		ExperimentalDowngradeCheckTime: DefaultDowngradeCheckTime,
+		DowngradeCheckTime:             DefaultDowngradeCheckTime,
+		MemoryMlock:                    false,
+		// TODO: delete in v3.7
+		ExperimentalMemoryMlock:             false,
+		ExperimentalStopGRPCServiceOnDefrag: false,
+		MaxLearners:                         membership.DefaultMaxLearners,
+
+		ExperimentalTxnModeWriteWithSharedBuffer:  DefaultExperimentalTxnModeWriteWithSharedBuffer,
+		ExperimentalDistributedTracingAddress:     DefaultDistributedTracingAddress,
+		DistributedTracingAddress:                 DefaultDistributedTracingAddress,
+		ExperimentalDistributedTracingServiceName: DefaultDistributedTracingServiceName,
+		DistributedTracingServiceName:             DefaultDistributedTracingServiceName,
+
+		CompactHashCheckTime: DefaultCompactHashCheckTime,
+		// TODO: delete in v3.7
+		ExperimentalCompactHashCheckTime: DefaultCompactHashCheckTime,
+
+		V2Deprecation: config.V2DeprDefault,
+
+		DiscoveryCfg: v3discovery.DiscoveryConfig{
+			ConfigSpec: clientv3.ConfigSpec{
+				DialTimeout:      DefaultDiscoveryDialTimeout,
+				RequestTimeout:   DefaultDiscoveryRequestTimeOut,
+				KeepAliveTime:    DefaultDiscoveryKeepAliveTime,
+				KeepAliveTimeout: DefaultDiscoveryKeepAliveTimeOut,
+
+				Secure: &clientv3.SecureConfig{
+					InsecureTransport: true,
+				},
+				Auth: &clientv3.AuthConfig{},
+			},
+		},
+
+		AutoCompactionMode:      DefaultAutoCompactionMode,
+		AutoCompactionRetention: DefaultAutoCompactionRetention,
+		ServerFeatureGate:       features.NewDefaultServerFeatureGate(DefaultName, nil),
+		FlagsExplicitlySet:      map[string]bool{},
+	}
+	cfg.InitialCluster = cfg.InitialClusterFromName(cfg.Name)
+	return cfg
+}
+
+func (cfg *Config) AddFlags(fs *flag.FlagSet) {
+	// member
+	fs.StringVar(&cfg.Dir, "data-dir", cfg.Dir, "Path to the data directory.")
+	fs.StringVar(&cfg.WalDir, "wal-dir", cfg.WalDir, "Path to the dedicated wal directory.")
+	fs.Var(
+		flags.NewUniqueURLsWithExceptions(DefaultListenPeerURLs, ""),
+		"listen-peer-urls",
+		"List of URLs to listen on for peer traffic.",
+	)
+	fs.Var(
+		flags.NewUniqueURLsWithExceptions(DefaultListenClientURLs, ""), "listen-client-urls",
+		"List of URLs to listen on for client grpc traffic and http as long as --listen-client-http-urls is not specified.",
+	)
+	fs.Var(
+		flags.NewUniqueURLsWithExceptions("", ""), "listen-client-http-urls",
+		"List of URLs to listen on for http only client traffic. Enabling this flag removes http services from --listen-client-urls.",
+	)
+	fs.Var(
+		flags.NewUniqueURLsWithExceptions("", ""),
+		"listen-metrics-urls",
+		"List of URLs to listen on for the metrics and health endpoints.",
+	)
+	fs.UintVar(&cfg.MaxSnapFiles, "max-snapshots", cfg.MaxSnapFiles, "Maximum number of snapshot files to retain (0 is unlimited). Deprecated in v3.6 and will be decommissioned in v3.7.")
+	fs.UintVar(&cfg.MaxWalFiles, "max-wals", cfg.MaxWalFiles, "Maximum number of wal files to retain (0 is unlimited).")
+	fs.StringVar(&cfg.Name, "name", cfg.Name, "Human-readable name for this member.")
+	fs.Uint64Var(&cfg.SnapshotCount, "snapshot-count", cfg.SnapshotCount, "Number of committed transactions to trigger a snapshot to disk. Deprecated in v3.6 and will be decommissioned in v3.7.")
+	fs.UintVar(&cfg.TickMs, "heartbeat-interval", cfg.TickMs, "Time (in milliseconds) of a heartbeat interval.")
+	fs.UintVar(&cfg.ElectionMs, "election-timeout", cfg.ElectionMs, "Time (in milliseconds) for an election to timeout.")
+	fs.BoolVar(&cfg.InitialElectionTickAdvance, "initial-election-tick-advance", cfg.InitialElectionTickAdvance, "Whether to fast-forward initial election ticks on boot for faster election.")
+	fs.Int64Var(&cfg.QuotaBackendBytes, "quota-backend-bytes", cfg.QuotaBackendBytes, "Sets the maximum size (in bytes) that the etcd backend database may consume. Exceeding this triggers an alarm and puts etcd in read-only mode. Set to 0 to use the default 2GiB limit.")
+	fs.StringVar(&cfg.BackendFreelistType, "backend-bbolt-freelist-type", cfg.BackendFreelistType, "BackendFreelistType specifies the type of freelist that boltdb backend uses(array and map are supported types)")
+	fs.DurationVar(&cfg.BackendBatchInterval, "backend-batch-interval", cfg.BackendBatchInterval, "BackendBatchInterval is the maximum time before commit the backend transaction.")
+	fs.IntVar(&cfg.BackendBatchLimit, "backend-batch-limit", cfg.BackendBatchLimit, "BackendBatchLimit is the maximum operations before commit the backend transaction.")
+	fs.UintVar(&cfg.MaxTxnOps, "max-txn-ops", cfg.MaxTxnOps, "Maximum number of operations permitted in a transaction.")
+	fs.UintVar(&cfg.MaxRequestBytes, "max-request-bytes", cfg.MaxRequestBytes, "Maximum client request size in bytes the server will accept.")
+	fs.DurationVar(&cfg.GRPCKeepAliveMinTime, "grpc-keepalive-min-time", cfg.GRPCKeepAliveMinTime, "Minimum interval duration that a client should wait before pinging server.")
+	fs.DurationVar(&cfg.GRPCKeepAliveInterval, "grpc-keepalive-interval", cfg.GRPCKeepAliveInterval, "Frequency duration of server-to-client ping to check if a connection is alive (0 to disable).")
+	fs.DurationVar(&cfg.GRPCKeepAliveTimeout, "grpc-keepalive-timeout", cfg.GRPCKeepAliveTimeout, "Additional duration of wait before closing a non-responsive connection (0 to disable).")
+	fs.BoolVar(&cfg.SocketOpts.ReusePort, "socket-reuse-port", cfg.SocketOpts.ReusePort, "Enable to set socket option SO_REUSEPORT on listeners allowing rebinding of a port already in use.")
+	fs.BoolVar(&cfg.SocketOpts.ReuseAddress, "socket-reuse-address", cfg.SocketOpts.ReuseAddress, "Enable to set socket option SO_REUSEADDR on listeners allowing binding to an address in `TIME_WAIT` state.")
+
+	fs.Var(flags.NewUint32Value(cfg.MaxConcurrentStreams), "max-concurrent-streams", "Maximum concurrent streams that each client can open at a time.")
+
+	// raft connection timeouts
+	fs.DurationVar(&rafthttp.ConnReadTimeout, "raft-read-timeout", rafthttp.DefaultConnReadTimeout, "Read timeout set on each rafthttp connection")
+	fs.DurationVar(&rafthttp.ConnWriteTimeout, "raft-write-timeout", rafthttp.DefaultConnWriteTimeout, "Write timeout set on each rafthttp connection")
+
+	// clustering
+	fs.Var(
+		flags.NewUniqueURLsWithExceptions(DefaultInitialAdvertisePeerURLs, ""),
+		"initial-advertise-peer-urls",
+		"List of this member's peer URLs to advertise to the rest of the cluster.",
+	)
+
+	fs.Var(
+		flags.NewUniqueURLsWithExceptions(DefaultAdvertiseClientURLs, ""),
+		"advertise-client-urls",
+		"List of this member's client URLs to advertise to the public.",
+	)
+
+	fs.StringVar(&cfg.Durl, "discovery", cfg.Durl, "Discovery URL used to bootstrap the cluster for v2 discovery. Will be deprecated in v3.7, and be decommissioned in v3.8.")
+
+	fs.Var(
+		flags.NewUniqueStringsValue(""),
+		"discovery-endpoints",
+		"V3 discovery: List of gRPC endpoints of the discovery service.",
+	)
+	fs.StringVar(&cfg.DiscoveryCfg.Token, "discovery-token", "", "V3 discovery: discovery token for the etcd cluster to be bootstrapped.")
+	fs.DurationVar(&cfg.DiscoveryCfg.DialTimeout, "discovery-dial-timeout", cfg.DiscoveryCfg.DialTimeout, "V3 discovery: dial timeout for client connections.")
+	fs.DurationVar(&cfg.DiscoveryCfg.RequestTimeout, "discovery-request-timeout", cfg.DiscoveryCfg.RequestTimeout, "V3 discovery: timeout for discovery requests (excluding dial timeout).")
+	fs.DurationVar(&cfg.DiscoveryCfg.KeepAliveTime, "discovery-keepalive-time", cfg.DiscoveryCfg.KeepAliveTime, "V3 discovery: keepalive time for client connections.")
+	fs.DurationVar(&cfg.DiscoveryCfg.KeepAliveTimeout, "discovery-keepalive-timeout", cfg.DiscoveryCfg.KeepAliveTimeout, "V3 discovery: keepalive timeout for client connections.")
+	fs.BoolVar(&cfg.DiscoveryCfg.Secure.InsecureTransport, "discovery-insecure-transport", true, "V3 discovery: disable transport security for client connections.")
+	fs.BoolVar(&cfg.DiscoveryCfg.Secure.InsecureSkipVerify, "discovery-insecure-skip-tls-verify", false, "V3 discovery: skip server certificate verification (CAUTION: this option should be enabled only for testing purposes).")
+	fs.StringVar(&cfg.DiscoveryCfg.Secure.Cert, "discovery-cert", "", "V3 discovery: identify secure client using this TLS certificate file.")
+	fs.StringVar(&cfg.DiscoveryCfg.Secure.Key, "discovery-key", "", "V3 discovery: identify secure client using this TLS key file.")
+	fs.StringVar(&cfg.DiscoveryCfg.Secure.Cacert, "discovery-cacert", "", "V3 discovery: verify certificates of TLS-enabled secure servers using this CA bundle.")
+	fs.StringVar(&cfg.DiscoveryCfg.Auth.Username, "discovery-user", "", "V3 discovery: username[:password] for authentication (prompt if password is not supplied).")
+	fs.StringVar(&cfg.DiscoveryCfg.Auth.Password, "discovery-password", "", "V3 discovery: password for authentication (if this option is used, --user option shouldn't include password).")
+
+	fs.StringVar(&cfg.Dproxy, "discovery-proxy", cfg.Dproxy, "HTTP proxy to use for traffic to discovery service. Will be deprecated in v3.7, and be decommissioned in v3.8.")
+	fs.StringVar(&cfg.DNSCluster, "discovery-srv", cfg.DNSCluster, "DNS domain used to bootstrap initial cluster.")
+	fs.StringVar(&cfg.DNSClusterServiceName, "discovery-srv-name", cfg.DNSClusterServiceName, "Service name to query when using DNS discovery.")
+	fs.StringVar(&cfg.InitialCluster, "initial-cluster", cfg.InitialCluster, "Initial cluster configuration for bootstrapping.")
+	fs.StringVar(&cfg.InitialClusterToken, "initial-cluster-token", cfg.InitialClusterToken, "Initial cluster token for the etcd cluster during bootstrap.")
+	fs.BoolVar(&cfg.StrictReconfigCheck, "strict-reconfig-check", cfg.StrictReconfigCheck, "Reject reconfiguration requests that would cause quorum loss.")
+
+	fs.BoolVar(&cfg.PreVote, "pre-vote", cfg.PreVote, "Enable the raft Pre-Vote algorithm to prevent disruption when a node that has been partitioned away rejoins the cluster.")
+
+	// security
+	fs.StringVar(&cfg.ClientTLSInfo.CertFile, "cert-file", "", "Path to the client server TLS cert file.")
+	fs.StringVar(&cfg.ClientTLSInfo.KeyFile, "key-file", "", "Path to the client server TLS key file.")
+	fs.StringVar(&cfg.ClientTLSInfo.ClientCertFile, "client-cert-file", "", "Path to an explicit peer client TLS cert file otherwise cert file will be used when client auth is required.")
+	fs.StringVar(&cfg.ClientTLSInfo.ClientKeyFile, "client-key-file", "", "Path to an explicit peer client TLS key file otherwise key file will be used when client auth is required.")
+	fs.BoolVar(&cfg.ClientTLSInfo.ClientCertAuth, "client-cert-auth", false, "Enable client cert authentication.")
+	fs.StringVar(&cfg.ClientTLSInfo.CRLFile, "client-crl-file", "", "Path to the client certificate revocation list file.")
+	fs.Var(flags.NewStringsValue(""), "client-cert-allowed-hostname", "Comma-separated list of allowed SAN hostnames for client cert authentication.")
+	fs.StringVar(&cfg.ClientTLSInfo.TrustedCAFile, "trusted-ca-file", "", "Path to the client server TLS trusted CA cert file.")
+	fs.BoolVar(&cfg.ClientAutoTLS, "auto-tls", false, "Client TLS using generated certificates")
+	fs.StringVar(&cfg.PeerTLSInfo.CertFile, "peer-cert-file", "", "Path to the peer server TLS cert file.")
+	fs.StringVar(&cfg.PeerTLSInfo.KeyFile, "peer-key-file", "", "Path to the peer server TLS key file.")
+	fs.StringVar(&cfg.PeerTLSInfo.ClientCertFile, "peer-client-cert-file", "", "Path to an explicit peer client TLS cert file otherwise peer cert file will be used when client auth is required.")
+	fs.StringVar(&cfg.PeerTLSInfo.ClientKeyFile, "peer-client-key-file", "", "Path to an explicit peer client TLS key file otherwise peer key file will be used when client auth is required.")
+	fs.BoolVar(&cfg.PeerTLSInfo.ClientCertAuth, "peer-client-cert-auth", false, "Enable peer client cert authentication.")
+	fs.StringVar(&cfg.PeerTLSInfo.TrustedCAFile, "peer-trusted-ca-file", "", "Path to the peer server TLS trusted CA file.")
+	fs.BoolVar(&cfg.PeerAutoTLS, "peer-auto-tls", false, "Peer TLS using generated certificates")
+	fs.UintVar(&cfg.SelfSignedCertValidity, "self-signed-cert-validity", 1, "The validity period of the client and peer certificates, unit is year")
+	fs.StringVar(&cfg.PeerTLSInfo.CRLFile, "peer-crl-file", "", "Path to the peer certificate revocation list file.")
+	fs.Var(flags.NewStringsValue(""), "peer-cert-allowed-cn", "Comma-separated list of allowed CNs for inter-peer TLS authentication.")
+	fs.Var(flags.NewStringsValue(""), "peer-cert-allowed-hostname", "Comma-separated list of allowed SAN hostnames for inter-peer TLS authentication.")
+	fs.Var(flags.NewStringsValue(""), "cipher-suites", "Comma-separated list of supported TLS cipher suites between client/server and peers (empty will be auto-populated by Go).")
+	fs.BoolVar(&cfg.ExperimentalPeerSkipClientSanVerification, "experimental-peer-skip-client-san-verification", false, "Skip verification of SAN field in client certificate for peer connections.Deprecated in v3.6 and will be decommissioned in v3.7. Use peer-skip-client-san-verification instead")
+	fs.BoolVar(&cfg.PeerTLSInfo.SkipClientSANVerify, "peer-skip-client-san-verification", false, "Skip verification of SAN field in client certificate for peer connections.")
+	fs.StringVar(&cfg.TlsMinVersion, "tls-min-version", string(tlsutil.TLSVersion12), "Minimum TLS version supported by etcd. Possible values: TLS1.2, TLS1.3.")
+	fs.StringVar(&cfg.TlsMaxVersion, "tls-max-version", string(tlsutil.TLSVersionDefault), "Maximum TLS version supported by etcd. Possible values: TLS1.2, TLS1.3 (empty defers to Go).")
+
+	fs.Var(
+		flags.NewUniqueURLsWithExceptions("*", "*"),
+		"cors",
+		"Comma-separated white list of origins for CORS, or cross-origin resource sharing, (empty or * means allow all)",
+	)
+	fs.Var(flags.NewUniqueStringsValue("*"), "host-whitelist", "Comma-separated acceptable hostnames from HTTP client requests, if server is not secure (empty means allow all).")
+
+	// logging
+	fs.StringVar(&cfg.Logger, "logger", "zap", "Currently only supports 'zap' for structured logging.")
+	fs.Var(flags.NewUniqueStringsValue(DefaultLogOutput), "log-outputs", "Specify 'stdout' or 'stderr' to skip journald logging even when running under systemd, or list of comma separated output targets.")
+	fs.StringVar(&cfg.LogLevel, "log-level", logutil.DefaultLogLevel, "Configures log level. Only supports debug, info, warn, error, panic, or fatal. Default 'info'.")
+	fs.StringVar(&cfg.LogFormat, "log-format", logutil.DefaultLogFormat, "Configures log format. Only supports json, console. Default is 'json'.")
+	fs.BoolVar(&cfg.EnableLogRotation, "enable-log-rotation", false, "Enable log rotation of a single log-outputs file target.")
+	fs.StringVar(&cfg.LogRotationConfigJSON, "log-rotation-config-json", DefaultLogRotationConfig, "Configures log rotation if enabled with a JSON logger config. Default: MaxSize=100(MB), MaxAge=0(days,no limit), MaxBackups=0(no limit), LocalTime=false(UTC), Compress=false(gzip)")
+
+	fs.StringVar(&cfg.AutoCompactionRetention, "auto-compaction-retention", "0", "Auto compaction retention for mvcc key value store. 0 means disable auto compaction.")
+	fs.StringVar(&cfg.AutoCompactionMode, "auto-compaction-mode", "periodic", "interpret 'auto-compaction-retention' one of: periodic|revision. 'periodic' for duration based retention, defaulting to hours if no time unit is provided (e.g. '5m'). 'revision' for revision number based retention.")
+
+	// pprof profiler via HTTP
+	fs.BoolVar(&cfg.EnablePprof, "enable-pprof", false, "Enable runtime profiling data via HTTP server. Address is at client URL + \"/debug/pprof/\"")
+
+	// additional metrics
+	fs.StringVar(&cfg.Metrics, "metrics", cfg.Metrics, "Set level of detail for exported metrics, specify 'extensive' to include server side grpc histogram metrics")
+
+	// experimental distributed tracing
+	fs.BoolVar(&cfg.ExperimentalEnableDistributedTracing, "experimental-enable-distributed-tracing", false, "Enable experimental distributed tracing using OpenTelemetry Tracing. Deprecated in v3.6 and will be decommissioned in v3.7. Use --enable-distributed-tracing instead.")
+	fs.BoolVar(&cfg.EnableDistributedTracing, "enable-distributed-tracing", false, "Enable distributed tracing using OpenTelemetry Tracing.")
+
+	fs.StringVar(&cfg.ExperimentalDistributedTracingAddress, "experimental-distributed-tracing-address", cfg.ExperimentalDistributedTracingAddress, "Address for distributed tracing used for OpenTelemetry Tracing (if enabled with experimental-enable-distributed-tracing flag). Deprecated in v3.6 and will be decommissioned in v3.7. Use --distributed-tracing-address instead.")
+	fs.StringVar(&cfg.DistributedTracingAddress, "distributed-tracing-address", cfg.DistributedTracingAddress, "Address for distributed tracing used for OpenTelemetry Tracing (if enabled with enable-distributed-tracing flag).")
+
+	fs.StringVar(&cfg.ExperimentalDistributedTracingServiceName, "experimental-distributed-tracing-service-name", cfg.ExperimentalDistributedTracingServiceName, "Configures service name for distributed tracing to be used to define service name for OpenTelemetry Tracing (if enabled with experimental-enable-distributed-tracing flag). 'etcd' is the default service name. Use the same service name for all instances of etcd. Deprecated in v3.6 and will be decommissioned in v3.7. Use --distributed-tracing-service-name instead.")
+	fs.StringVar(&cfg.DistributedTracingServiceName, "distributed-tracing-service-name", cfg.DistributedTracingServiceName, "Configures service name for distributed tracing to be used to define service name for OpenTelemetry Tracing (if enabled with enable-distributed-tracing flag). 'etcd' is the default service name. Use the same service name for all instances of etcd.")
+
+	fs.StringVar(&cfg.ExperimentalDistributedTracingServiceInstanceID, "experimental-distributed-tracing-instance-id", "", "Configures service instance ID for distributed tracing to be used to define service instance ID key for OpenTelemetry Tracing (if enabled with experimental-enable-distributed-tracing flag). There is no default value set. This ID must be unique per etcd instance. Deprecated in v3.6 and will be decommissioned in v3.7. Use --distributed-tracing-instance-id instead.")
+	fs.StringVar(&cfg.DistributedTracingServiceInstanceID, "distributed-tracing-instance-id", "", "Configures service instance ID for distributed tracing to be used to define service instance ID key for OpenTelemetry Tracing (if enabled with enable-distributed-tracing flag). There is no default value set. This ID must be unique per etcd instance.")
+
+	fs.IntVar(&cfg.ExperimentalDistributedTracingSamplingRatePerMillion, "experimental-distributed-tracing-sampling-rate", 0, "Number of samples to collect per million spans for OpenTelemetry Tracing (if enabled with experimental-enable-distributed-tracing flag). Deprecated in v3.6 and will be decommissioned in v3.7. Use --distributed-tracing-sampling-rate instead.")
+	fs.IntVar(&cfg.DistributedTracingSamplingRatePerMillion, "distributed-tracing-sampling-rate", 0, "Number of samples to collect per million spans for OpenTelemetry Tracing (if enabled with enable-distributed-tracing flag).")
+
+	// auth
+	fs.StringVar(&cfg.AuthToken, "auth-token", cfg.AuthToken, "Specify auth token specific options.")
+	fs.UintVar(&cfg.BcryptCost, "bcrypt-cost", cfg.BcryptCost, "Specify bcrypt algorithm cost factor for auth password hashing.")
+	fs.UintVar(&cfg.AuthTokenTTL, "auth-token-ttl", cfg.AuthTokenTTL, "The lifetime in seconds of the auth token.")
+
+	// gateway
+	fs.BoolVar(&cfg.EnableGRPCGateway, "enable-grpc-gateway", cfg.EnableGRPCGateway, "Enable GRPC gateway.")
+
+	// experimental
+	fs.BoolVar(&cfg.ExperimentalInitialCorruptCheck, "experimental-initial-corrupt-check", cfg.ExperimentalInitialCorruptCheck, "Enable to check data corruption before serving any client/peer traffic.")
+	// TODO: delete in v3.7
+	fs.DurationVar(&cfg.ExperimentalCorruptCheckTime, "experimental-corrupt-check-time", cfg.ExperimentalCorruptCheckTime, "Duration of time between cluster corruption check passes. Deprecated in v3.6 and will be decommissioned in v3.7. Use --corrupt-check-time instead")
+	fs.DurationVar(&cfg.CorruptCheckTime, "corrupt-check-time", cfg.CorruptCheckTime, "Duration of time between cluster corruption check passes.")
+	// TODO: delete in v3.7
+	fs.BoolVar(&cfg.ExperimentalCompactHashCheckEnabled, "experimental-compact-hash-check-enabled", cfg.ExperimentalCompactHashCheckEnabled, "Enable leader to periodically check followers compaction hashes. Deprecated in v3.6 and will be decommissioned in v3.7. Use '--feature-gates=CompactHashCheck=true' instead")
+	fs.DurationVar(&cfg.ExperimentalCompactHashCheckTime, "experimental-compact-hash-check-time", cfg.ExperimentalCompactHashCheckTime, "Duration of time between leader checks followers compaction hashes. Deprecated in v3.6 and will be decommissioned in v3.7. Use --compact-hash-check-time instead.")
+
+	fs.DurationVar(&cfg.CompactHashCheckTime, "compact-hash-check-time", cfg.CompactHashCheckTime, "Duration of time between leader checks followers compaction hashes.")
+
+	fs.BoolVar(&cfg.ExperimentalEnableLeaseCheckpoint, "experimental-enable-lease-checkpoint", false, "Enable leader to send regular checkpoints to other members to prevent reset of remaining TTL on leader change.")
+	// TODO: delete in v3.7
+	fs.BoolVar(&cfg.ExperimentalEnableLeaseCheckpointPersist, "experimental-enable-lease-checkpoint-persist", false, "Enable persisting remainingTTL to prevent indefinite auto-renewal of long lived leases. Always enabled in v3.6. Should be used to ensure smooth upgrade from v3.5 clusters with this feature enabled. Requires experimental-enable-lease-checkpoint to be enabled.")
+	// TODO: delete in v3.7
+	fs.IntVar(&cfg.ExperimentalCompactionBatchLimit, "experimental-compaction-batch-limit", cfg.ExperimentalCompactionBatchLimit, "Sets the maximum revisions deleted in each compaction batch. Deprecated in v3.6 and will be decommissioned in v3.7. Use --compaction-batch-limit instead.")
+	fs.IntVar(&cfg.CompactionBatchLimit, "compaction-batch-limit", cfg.CompactionBatchLimit, "Sets the maximum revisions deleted in each compaction batch.")
+	fs.DurationVar(&cfg.ExperimentalCompactionSleepInterval, "experimental-compaction-sleep-interval", cfg.ExperimentalCompactionSleepInterval, "Sets the sleep interval between each compaction batch. Deprecated in v3.6 and will be decommissioned in v3.7. Use --compaction-sleep-interval instead.")
+	fs.DurationVar(&cfg.CompactionSleepInterval, "compaction-sleep-interval", cfg.CompactionSleepInterval, "Sets the sleep interval between each compaction batch.")
+	// TODO: delete in v3.7
+	fs.DurationVar(&cfg.ExperimentalWatchProgressNotifyInterval, "experimental-watch-progress-notify-interval", cfg.ExperimentalWatchProgressNotifyInterval, "Duration of periodic watch progress notifications. Deprecated in v3.6 and will be decommissioned in v3.7. Use --watch-progress-notify-interval instead.")
+	fs.DurationVar(&cfg.WatchProgressNotifyInterval, "watch-progress-notify-interval", cfg.WatchProgressNotifyInterval, "Duration of periodic watch progress notifications.")
+	fs.DurationVar(&cfg.DowngradeCheckTime, "downgrade-check-time", cfg.DowngradeCheckTime, "Duration of time between two downgrade status checks.")
+	// TODO: delete in v3.7
+	fs.DurationVar(&cfg.ExperimentalDowngradeCheckTime, "experimental-downgrade-check-time", cfg.ExperimentalDowngradeCheckTime, "Duration of time between two downgrade status checks. Deprecated in v3.6 and will be decommissioned in v3.7. Use --downgrade-check-time instead.")
+	// TODO: delete in v3.7
+	fs.DurationVar(&cfg.ExperimentalWarningApplyDuration, "experimental-warning-apply-duration", cfg.ExperimentalWarningApplyDuration, "Time duration after which a warning is generated if request takes more time. Deprecated in v3.6 and will be decommissioned in v3.7. Use --warning-watch-progress-duration instead.")
+	fs.DurationVar(&cfg.WarningApplyDuration, "warning-apply-duration", cfg.WarningApplyDuration, "Time duration after which a warning is generated if watch progress takes more time.")
+	fs.DurationVar(&cfg.WarningUnaryRequestDuration, "warning-unary-request-duration", cfg.WarningUnaryRequestDuration, "Time duration after which a warning is generated if a unary request takes more time.")
+	fs.DurationVar(&cfg.ExperimentalWarningUnaryRequestDuration, "experimental-warning-unary-request-duration", cfg.ExperimentalWarningUnaryRequestDuration, "Time duration after which a warning is generated if a unary request takes more time. It's deprecated, and will be decommissioned in v3.7. Use --warning-unary-request-duration instead.")
+	// TODO: delete in v3.7
+	fs.BoolVar(&cfg.ExperimentalMemoryMlock, "experimental-memory-mlock", cfg.ExperimentalMemoryMlock, "Enable to enforce etcd pages (in particular bbolt) to stay in RAM.")
+	fs.BoolVar(&cfg.MemoryMlock, "memory-mlock", cfg.MemoryMlock, "Enable to enforce etcd pages (in particular bbolt) to stay in RAM.")
+	fs.BoolVar(&cfg.ExperimentalTxnModeWriteWithSharedBuffer, "experimental-txn-mode-write-with-shared-buffer", true, "Enable the write transaction to use a shared buffer in its readonly check operations.")
+	fs.BoolVar(&cfg.ExperimentalStopGRPCServiceOnDefrag, "experimental-stop-grpc-service-on-defrag", cfg.ExperimentalStopGRPCServiceOnDefrag, "Enable etcd gRPC service to stop serving client requests on defragmentation.")
+	// TODO: delete in v3.7
+	fs.UintVar(&cfg.ExperimentalBootstrapDefragThresholdMegabytes, "experimental-bootstrap-defrag-threshold-megabytes", 0, "Enable the defrag during etcd server bootstrap on condition that it will free at least the provided threshold of disk space. Needs to be set to non-zero value to take effect. It's deprecated, and will be decommissioned in v3.7. Use --bootstrap-defrag-threshold-megabytes instead.")
+	fs.UintVar(&cfg.BootstrapDefragThresholdMegabytes, "bootstrap-defrag-threshold-megabytes", 0, "Enable the defrag during etcd server bootstrap on condition that it will free at least the provided threshold of disk space. Needs to be set to non-zero value to take effect.")
+	// TODO: delete in v3.7
+	fs.IntVar(&cfg.MaxLearners, "max-learners", membership.DefaultMaxLearners, "Sets the maximum number of learners that can be available in the cluster membership.")
+	fs.Uint64Var(&cfg.ExperimentalSnapshotCatchUpEntries, "experimental-snapshot-catchup-entries", cfg.ExperimentalSnapshotCatchUpEntries, "Number of entries for a slow follower to catch up after compacting the raft storage entries. Deprecated in v3.6 and will be decommissioned in v3.7. Use --snapshot-catchup-entries instead.")
+	fs.Uint64Var(&cfg.SnapshotCatchUpEntries, "snapshot-catchup-entries", cfg.SnapshotCatchUpEntries, "Number of entries for a slow follower to catch up after compacting the raft storage entries.")
+
+	// unsafe
+	fs.BoolVar(&cfg.UnsafeNoFsync, "unsafe-no-fsync", false, "Disables fsync, unsafe, will cause data loss.")
+	fs.BoolVar(&cfg.ForceNewCluster, "force-new-cluster", false, "Force to create a new one member cluster.")
+
+	// featuregate
+	cfg.ServerFeatureGate.(featuregate.MutableFeatureGate).AddFlag(fs, ServerFeatureGateFlagName)
+}
+
+func ConfigFromFile(path string) (*Config, error) {
+	cfg := &configYAML{Config: *NewConfig()}
+	if err := cfg.configFromFile(path); err != nil {
+		return nil, err
+	}
+	return &cfg.Config, nil
+}
+
+func (cfg *configYAML) configFromFile(path string) error {
+	b, err := os.ReadFile(path)
+	if err != nil {
+		return err
+	}
+
+	defaultInitialCluster := cfg.InitialCluster
+
+	err = yaml.Unmarshal(b, cfg)
+	if err != nil {
+		return err
+	}
+
+	if cfg.configJSON.ServerFeatureGatesJSON != "" {
+		err = cfg.Config.ServerFeatureGate.(featuregate.MutableFeatureGate).Set(cfg.configJSON.ServerFeatureGatesJSON)
+		if err != nil {
+			return err
+		}
+	}
+
+	// parses the yaml bytes to raw map first, then getBoolFlagVal can get the top level bool flag value.
+	var cfgMap map[string]any
+	err = yaml.Unmarshal(b, &cfgMap)
+	if err != nil {
+		return err
+	}
+
+	for flg := range cfgMap {
+		cfg.FlagsExplicitlySet[flg] = true
+	}
+
+	if peerTransportSecurity, ok := cfgMap["peer-transport-security"]; ok {
+		peerTransportSecurityMap, isMap := peerTransportSecurity.(map[string]any)
+		if !isMap {
+			return fmt.Errorf("invalid peer-transport-security")
+		}
+		for k := range peerTransportSecurityMap {
+			cfg.FlagsExplicitlySet[fmt.Sprintf("peer-%s", k)] = true
+		}
+	}
+
+	// attempt to fix a bug introduced in https://github.com/etcd-io/etcd/pull/15033
+	// both `experimental-snapshot-catch-up-entries` and `experimental-snapshot-catchup-entries` refer to the same field,
+	// 	map the YAML field "experimental-snapshot-catch-up-entries" to the flag "experimental-snapshot-catchup-entries".
+	if val, ok := cfgMap["experimental-snapshot-catch-up-entries"]; ok {
+		cfgMap["experimental-snapshot-catchup-entries"] = val
+		cfg.ExperimentalSnapshotCatchUpEntries = uint64(val.(float64))
+		cfg.FlagsExplicitlySet["experimental-snapshot-catchup-entries"] = true
+	}
+
+	getBoolFlagVal := func(flagName string) *bool {
+		flagVal, ok := cfgMap[flagName]
+		if !ok {
+			return nil
+		}
+		boolVal := flagVal.(bool)
+		return &boolVal
+	}
+	err = SetFeatureGatesFromExperimentalFlags(cfg.ServerFeatureGate, getBoolFlagVal, cfg.configJSON.ServerFeatureGatesJSON)
+	if err != nil {
+		return err
+	}
+
+	if cfg.configJSON.ListenPeerURLs != "" {
+		u, err := types.NewURLs(strings.Split(cfg.configJSON.ListenPeerURLs, ","))
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "unexpected error setting up listen-peer-urls: %v\n", err)
+			os.Exit(1)
+		}
+		cfg.Config.ListenPeerUrls = u
+	}
+
+	if cfg.configJSON.ListenClientURLs != "" {
+		u, err := types.NewURLs(strings.Split(cfg.configJSON.ListenClientURLs, ","))
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "unexpected error setting up listen-client-urls: %v\n", err)
+			os.Exit(1)
+		}
+		cfg.Config.ListenClientUrls = u
+	}
+
+	if cfg.configJSON.ListenClientHTTPURLs != "" {
+		u, err := types.NewURLs(strings.Split(cfg.configJSON.ListenClientHTTPURLs, ","))
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "unexpected error setting up listen-client-http-urls: %v\n", err)
+			os.Exit(1)
+		}
+		cfg.Config.ListenClientHttpUrls = u
+	}
+
+	if cfg.configJSON.AdvertisePeerURLs != "" {
+		u, err := types.NewURLs(strings.Split(cfg.configJSON.AdvertisePeerURLs, ","))
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "unexpected error setting up initial-advertise-peer-urls: %v\n", err)
+			os.Exit(1)
+		}
+		cfg.Config.AdvertisePeerUrls = u
+	}
+
+	if cfg.configJSON.AdvertiseClientURLs != "" {
+		u, err := types.NewURLs(strings.Split(cfg.configJSON.AdvertiseClientURLs, ","))
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "unexpected error setting up advertise-peer-urls: %v\n", err)
+			os.Exit(1)
+		}
+		cfg.Config.AdvertiseClientUrls = u
+	}
+
+	if cfg.ListenMetricsUrlsJSON != "" {
+		u, err := types.NewURLs(strings.Split(cfg.ListenMetricsUrlsJSON, ","))
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "unexpected error setting up listen-metrics-urls: %v\n", err)
+			os.Exit(1)
+		}
+		cfg.ListenMetricsUrls = u
+	}
+
+	if cfg.CORSJSON != "" {
+		uv := flags.NewUniqueURLsWithExceptions(cfg.CORSJSON, "*")
+		cfg.CORS = uv.Values
+	}
+
+	if cfg.HostWhitelistJSON != "" {
+		uv := flags.NewUniqueStringsValue(cfg.HostWhitelistJSON)
+		cfg.HostWhitelist = uv.Values
+	}
+
+	// If a discovery or discovery-endpoints flag is set, clear default initial cluster set by InitialClusterFromName
+	if (cfg.Durl != "" || cfg.DNSCluster != "" || len(cfg.DiscoveryCfg.Endpoints) > 0) && cfg.InitialCluster == defaultInitialCluster {
+		cfg.InitialCluster = ""
+	}
+	if cfg.ClusterState == "" {
+		cfg.ClusterState = ClusterStateFlagNew
+	}
+
+	copySecurityDetails := func(tls *transport.TLSInfo, ysc *securityConfig) {
+		tls.CertFile = ysc.CertFile
+		tls.KeyFile = ysc.KeyFile
+		tls.ClientCertFile = ysc.ClientCertFile
+		tls.ClientKeyFile = ysc.ClientKeyFile
+		tls.ClientCertAuth = ysc.CertAuth
+		tls.TrustedCAFile = ysc.TrustedCAFile
+		tls.AllowedCNs = ysc.AllowedCNs
+		tls.AllowedHostnames = ysc.AllowedHostnames
+		tls.SkipClientSANVerify = ysc.SkipClientSANVerify
+	}
+	copySecurityDetails(&cfg.ClientTLSInfo, &cfg.ClientSecurityJSON)
+	copySecurityDetails(&cfg.PeerTLSInfo, &cfg.PeerSecurityJSON)
+	cfg.ClientAutoTLS = cfg.ClientSecurityJSON.AutoTLS
+	cfg.PeerAutoTLS = cfg.PeerSecurityJSON.AutoTLS
+	if cfg.SelfSignedCertValidity == 0 {
+		cfg.SelfSignedCertValidity = 1
+	}
+	return cfg.Validate()
+}
+
+// SetFeatureGatesFromExperimentalFlags sets the feature gate values if the feature gate is not explicitly set
+// while their corresponding experimental flags are explicitly set, for all the features in ExperimentalFlagToFeatureMap.
+// TODO: remove after all experimental flags are deprecated.
+func SetFeatureGatesFromExperimentalFlags(fg featuregate.FeatureGate, getExperimentalFlagVal func(string) *bool, featureGatesVal string) error {
+	m := make(map[featuregate.Feature]bool)
+	// verify that the feature gate and its experimental flag are not both set at the same time.
+	for expFlagName, featureName := range features.ExperimentalFlagToFeatureMap {
+		flagVal := getExperimentalFlagVal(expFlagName)
+		if flagVal == nil {
+			continue
+		}
+		if strings.Contains(featureGatesVal, string(featureName)) {
+			return fmt.Errorf("cannot specify both flags: --%s=%v and --%s=%s=%v at the same time, please just use --%s=%s=%v",
+				expFlagName, *flagVal, ServerFeatureGateFlagName, featureName, fg.Enabled(featureName), ServerFeatureGateFlagName, featureName, fg.Enabled(featureName))
+		}
+		m[featureName] = *flagVal
+	}
+
+	// filter out unknown features for fg, because we could use SetFeatureGatesFromExperimentalFlags both for
+	// server and cluster level feature gates.
+	allFeatures := fg.(featuregate.MutableFeatureGate).GetAll()
+	mFiltered := make(map[string]bool)
+	for k, v := range m {
+		if _, ok := allFeatures[k]; ok {
+			mFiltered[string(k)] = v
+		}
+	}
+	return fg.(featuregate.MutableFeatureGate).SetFromMap(mFiltered)
+}
+
+func updateCipherSuites(tls *transport.TLSInfo, ss []string) error {
+	if len(tls.CipherSuites) > 0 && len(ss) > 0 {
+		return fmt.Errorf("TLSInfo.CipherSuites is already specified (given %v)", ss)
+	}
+	if len(ss) > 0 {
+		cs, err := tlsutil.GetCipherSuites(ss)
+		if err != nil {
+			return err
+		}
+		tls.CipherSuites = cs
+	}
+	return nil
+}
+
+func updateMinMaxVersions(info *transport.TLSInfo, min, max string) {
+	// Validate() has been called to check the user input, so it should never fail.
+	var err error
+	if info.MinVersion, err = tlsutil.GetTLSVersion(min); err != nil {
+		panic(err)
+	}
+	if info.MaxVersion, err = tlsutil.GetTLSVersion(max); err != nil {
+		panic(err)
+	}
+}
+
+// Validate ensures that '*embed.Config' fields are properly configured.
+func (cfg *Config) Validate() error {
+	// make sure there is no conflict in the flag settings in the ExperimentalNonBoolFlagMigrationMap
+	// TODO: delete in v3.7
+	for oldFlag, newFlag := range experimentalFlagMigrationMap {
+		if cfg.FlagsExplicitlySet[oldFlag] && cfg.FlagsExplicitlySet[newFlag] {
+			return fmt.Errorf("cannot set --%s and --%s at the same time, please use --%s only", oldFlag, newFlag, newFlag)
+		}
+	}
+
+	if err := cfg.setupLogging(); err != nil {
+		return err
+	}
+	if err := checkBindURLs(cfg.ListenPeerUrls); err != nil {
+		return err
+	}
+	if err := checkBindURLs(cfg.ListenClientUrls); err != nil {
+		return err
+	}
+	if err := checkBindURLs(cfg.ListenClientHttpUrls); err != nil {
+		return err
+	}
+	if len(cfg.ListenClientHttpUrls) == 0 {
+		cfg.logger.Warn("Running http and grpc server on single port. This is not recommended for production.")
+	}
+	if err := checkBindURLs(cfg.ListenMetricsUrls); err != nil {
+		return err
+	}
+	if err := checkHostURLs(cfg.AdvertisePeerUrls); err != nil {
+		addrs := cfg.getAdvertisePeerURLs()
+		return fmt.Errorf(`--initial-advertise-peer-urls %q must be "host:port" (%w)`, strings.Join(addrs, ","), err)
+	}
+	if err := checkHostURLs(cfg.AdvertiseClientUrls); err != nil {
+		addrs := cfg.getAdvertiseClientURLs()
+		return fmt.Errorf(`--advertise-client-urls %q must be "host:port" (%w)`, strings.Join(addrs, ","), err)
+	}
+	// Check if conflicting flags are passed.
+	nSet := 0
+	for _, v := range []bool{cfg.Durl != "", cfg.InitialCluster != "", cfg.DNSCluster != "", len(cfg.DiscoveryCfg.Endpoints) > 0} {
+		if v {
+			nSet++
+		}
+	}
+
+	if cfg.ClusterState != ClusterStateFlagNew && cfg.ClusterState != ClusterStateFlagExisting {
+		return fmt.Errorf("unexpected clusterState %q", cfg.ClusterState)
+	}
+
+	if nSet > 1 {
+		return ErrConflictBootstrapFlags
+	}
+
+	// Check if both v2 discovery and v3 discovery flags are passed.
+	v2discoveryFlagsExist := cfg.Dproxy != ""
+	v3discoveryFlagsExist := len(cfg.DiscoveryCfg.Endpoints) > 0 ||
+		cfg.DiscoveryCfg.Token != "" ||
+		cfg.DiscoveryCfg.Secure.Cert != "" ||
+		cfg.DiscoveryCfg.Secure.Key != "" ||
+		cfg.DiscoveryCfg.Secure.Cacert != "" ||
+		cfg.DiscoveryCfg.Auth.Username != "" ||
+		cfg.DiscoveryCfg.Auth.Password != ""
+
+	if v2discoveryFlagsExist && v3discoveryFlagsExist {
+		return errors.New("both v2 discovery settings (discovery, discovery-proxy) " +
+			"and v3 discovery settings (discovery-token, discovery-endpoints, discovery-cert, " +
+			"discovery-key, discovery-cacert, discovery-user, discovery-password) are set")
+	}
+
+	// If one of `discovery-token` and `discovery-endpoints` is provided,
+	// then the other one must be provided as well.
+	if (cfg.DiscoveryCfg.Token != "") != (len(cfg.DiscoveryCfg.Endpoints) > 0) {
+		return errors.New("both --discovery-token and --discovery-endpoints must be set")
+	}
+
+	for _, ep := range cfg.DiscoveryCfg.Endpoints {
+		if strings.TrimSpace(ep) == "" {
+			return errors.New("--discovery-endpoints must not contain empty endpoints")
+		}
+	}
+
+	if cfg.TickMs == 0 {
+		return fmt.Errorf("--heartbeat-interval must be >0 (set to %dms)", cfg.TickMs)
+	}
+	if cfg.ElectionMs == 0 {
+		return fmt.Errorf("--election-timeout must be >0 (set to %dms)", cfg.ElectionMs)
+	}
+	if 5*cfg.TickMs > cfg.ElectionMs {
+		return fmt.Errorf("--election-timeout[%vms] should be at least as 5 times as --heartbeat-interval[%vms]", cfg.ElectionMs, cfg.TickMs)
+	}
+	if cfg.ElectionMs > maxElectionMs {
+		return fmt.Errorf("--election-timeout[%vms] is too long, and should be set less than %vms", cfg.ElectionMs, maxElectionMs)
+	}
+
+	// check this last since proxying in etcdmain may make this OK
+	if cfg.ListenClientUrls != nil && cfg.AdvertiseClientUrls == nil {
+		return ErrUnsetAdvertiseClientURLsFlag
+	}
+
+	switch cfg.AutoCompactionMode {
+	case CompactorModeRevision, CompactorModePeriodic:
+	case "":
+		return errors.New("undefined auto-compaction-mode")
+	default:
+		return fmt.Errorf("unknown auto-compaction-mode %q", cfg.AutoCompactionMode)
+	}
+
+	// Validate distributed tracing configuration but only if enabled.
+	if cfg.EnableDistributedTracing {
+		if err := validateTracingConfig(cfg.DistributedTracingSamplingRatePerMillion); err != nil {
+			return fmt.Errorf("distributed tracing configurition is not valid: (%w)", err)
+		}
+	}
+
+	if !cfg.ServerFeatureGate.Enabled(features.LeaseCheckpointPersist) && cfg.ServerFeatureGate.Enabled(features.LeaseCheckpoint) {
+		cfg.logger.Warn("Detected that checkpointing is enabled without persistence. Consider enabling feature gate LeaseCheckpointPersist")
+	}
+
+	if cfg.ServerFeatureGate.Enabled(features.LeaseCheckpointPersist) && !cfg.ServerFeatureGate.Enabled(features.LeaseCheckpoint) {
+		return fmt.Errorf("enabling feature gate LeaseCheckpointPersist requires enabling feature gate LeaseCheckpoint")
+	}
+	// TODO: delete in v3.7
+	if cfg.ExperimentalCompactHashCheckTime <= 0 {
+		return fmt.Errorf("--experimental-compact-hash-check-time must be >0 (set to %v)", cfg.ExperimentalCompactHashCheckTime)
+	}
+	if cfg.CompactHashCheckTime <= 0 {
+		return fmt.Errorf("--compact-hash-check-time must be >0 (set to %v)", cfg.CompactHashCheckTime)
+	}
+
+	// If `--name` isn't configured, then multiple members may have the same "default" name.
+	// When adding a new member with the "default" name as well, etcd may regards its peerURL
+	// as one additional peerURL of the existing member which has the same "default" name,
+	// because each member can have multiple client or peer URLs.
+	// Please refer to https://github.com/etcd-io/etcd/issues/13757
+	if cfg.Name == DefaultName {
+		cfg.logger.Warn(
+			"it isn't recommended to use default name, please set a value for --name. "+
+				"Note that etcd might run into issue when multiple members have the same default name",
+			zap.String("name", cfg.Name))
+	}
+
+	minVersion, err := tlsutil.GetTLSVersion(cfg.TlsMinVersion)
+	if err != nil {
+		return err
+	}
+	maxVersion, err := tlsutil.GetTLSVersion(cfg.TlsMaxVersion)
+	if err != nil {
+		return err
+	}
+
+	// maxVersion == 0 means that Go selects the highest available version.
+	if maxVersion != 0 && minVersion > maxVersion {
+		return fmt.Errorf("min version (%s) is greater than max version (%s)", cfg.TlsMinVersion, cfg.TlsMaxVersion)
+	}
+
+	// Check if user attempted to configure ciphers for TLS1.3 only: Go does not support that currently.
+	if minVersion == tls.VersionTLS13 && len(cfg.CipherSuites) > 0 {
+		return fmt.Errorf("cipher suites cannot be configured when only TLS1.3 is enabled")
+	}
+
+	return nil
+}
+
+// PeerURLsMapAndToken sets up an initial peer URLsMap and cluster token for bootstrap or discovery.
+func (cfg *Config) PeerURLsMapAndToken(which string) (urlsmap types.URLsMap, token string, err error) {
+	token = cfg.InitialClusterToken
+	switch {
+	case cfg.Durl != "":
+		urlsmap = types.URLsMap{}
+		// If using v2 discovery, generate a temporary cluster based on
+		// self's advertised peer URLs
+		urlsmap[cfg.Name] = cfg.AdvertisePeerUrls
+		token = cfg.Durl
+
+	case len(cfg.DiscoveryCfg.Endpoints) > 0:
+		urlsmap = types.URLsMap{}
+		// If using v3 discovery, generate a temporary cluster based on
+		// self's advertised peer URLs
+		urlsmap[cfg.Name] = cfg.AdvertisePeerUrls
+		token = cfg.DiscoveryCfg.Token
+
+	case cfg.DNSCluster != "":
+		clusterStrs, cerr := cfg.GetDNSClusterNames()
+		lg := cfg.logger
+		if cerr != nil {
+			lg.Warn("failed to resolve during SRV discovery", zap.Error(cerr))
+		}
+		if len(clusterStrs) == 0 {
+			return nil, "", cerr
+		}
+		for _, s := range clusterStrs {
+			lg.Info("got bootstrap from DNS for etcd-server", zap.String("node", s))
+		}
+		clusterStr := strings.Join(clusterStrs, ",")
+		if strings.Contains(clusterStr, "https://") && cfg.PeerTLSInfo.TrustedCAFile == "" {
+			cfg.PeerTLSInfo.ServerName = cfg.DNSCluster
+		}
+		urlsmap, err = types.NewURLsMap(clusterStr)
+		// only etcd member must belong to the discovered cluster.
+		// proxy does not need to belong to the discovered cluster.
+		if which == "etcd" {
+			if _, ok := urlsmap[cfg.Name]; !ok {
+				return nil, "", fmt.Errorf("cannot find local etcd member %q in SRV records", cfg.Name)
+			}
+		}
+
+	default:
+		// We're statically configured, and cluster has appropriately been set.
+		urlsmap, err = types.NewURLsMap(cfg.InitialCluster)
+	}
+	return urlsmap, token, err
+}
+
+// GetDNSClusterNames uses DNS SRV records to get a list of initial nodes for cluster bootstrapping.
+// This function will return a list of one or more nodes, as well as any errors encountered while
+// performing service discovery.
+// Note: Because this checks multiple sets of SRV records, discovery should only be considered to have
+// failed if the returned node list is empty.
+func (cfg *Config) GetDNSClusterNames() ([]string, error) {
+	var (
+		clusterStrs       []string
+		cerr              error
+		serviceNameSuffix string
+	)
+	if cfg.DNSClusterServiceName != "" {
+		serviceNameSuffix = "-" + cfg.DNSClusterServiceName
+	}
+
+	lg := cfg.GetLogger()
+
+	// Use both etcd-server-ssl and etcd-server for discovery.
+	// Combine the results if both are available.
+	clusterStrs, cerr = getCluster("https", "etcd-server-ssl"+serviceNameSuffix, cfg.Name, cfg.DNSCluster, cfg.AdvertisePeerUrls)
+	if cerr != nil {
+		clusterStrs = make([]string, 0)
+	}
+	lg.Info(
+		"get cluster for etcd-server-ssl SRV",
+		zap.String("service-scheme", "https"),
+		zap.String("service-name", "etcd-server-ssl"+serviceNameSuffix),
+		zap.String("server-name", cfg.Name),
+		zap.String("discovery-srv", cfg.DNSCluster),
+		zap.Strings("advertise-peer-urls", cfg.getAdvertisePeerURLs()),
+		zap.Strings("found-cluster", clusterStrs),
+		zap.Error(cerr),
+	)
+
+	defaultHTTPClusterStrs, httpCerr := getCluster("http", "etcd-server"+serviceNameSuffix, cfg.Name, cfg.DNSCluster, cfg.AdvertisePeerUrls)
+	if httpCerr == nil {
+		clusterStrs = append(clusterStrs, defaultHTTPClusterStrs...)
+	}
+	lg.Info(
+		"get cluster for etcd-server SRV",
+		zap.String("service-scheme", "http"),
+		zap.String("service-name", "etcd-server"+serviceNameSuffix),
+		zap.String("server-name", cfg.Name),
+		zap.String("discovery-srv", cfg.DNSCluster),
+		zap.Strings("advertise-peer-urls", cfg.getAdvertisePeerURLs()),
+		zap.Strings("found-cluster", clusterStrs),
+		zap.Error(httpCerr),
+	)
+
+	return clusterStrs, errors.Join(cerr, httpCerr)
+}
+
+func (cfg *Config) InitialClusterFromName(name string) (ret string) {
+	if len(cfg.AdvertisePeerUrls) == 0 {
+		return ""
+	}
+	n := name
+	if name == "" {
+		n = DefaultName
+	}
+	for i := range cfg.AdvertisePeerUrls {
+		ret = ret + "," + n + "=" + cfg.AdvertisePeerUrls[i].String()
+	}
+	return ret[1:]
+}
+
+// InferLocalAddr tries to determine the LocalAddr used when communicating with
+// an etcd peer. If SetMemberLocalAddr is true, then it will try to get the host
+// from AdvertisePeerUrls by searching for the first URL with a specified
+// non-loopback address. Otherwise, it defaults to empty string and the
+// LocalAddr used will be the default for the Golang HTTP client.
+func (cfg *Config) InferLocalAddr() string {
+	if !cfg.ServerFeatureGate.Enabled(features.SetMemberLocalAddr) {
+		return ""
+	}
+
+	lg := cfg.GetLogger()
+	lg.Info(
+		"searching for a suitable member local address in AdvertisePeerURLs",
+		zap.Strings("advertise-peer-urls", cfg.getAdvertisePeerURLs()),
+	)
+	for _, peerURL := range cfg.AdvertisePeerUrls {
+		if addr, err := netip.ParseAddr(peerURL.Hostname()); err == nil {
+			if addr.IsLoopback() || addr.IsUnspecified() {
+				continue
+			}
+			lg.Info(
+				"setting member local address",
+				zap.String("LocalAddr", addr.String()),
+			)
+			return addr.String()
+		}
+	}
+	lg.Warn(
+		"unable to set a member local address due to lack of suitable local addresses",
+		zap.Strings("advertise-peer-urls", cfg.getAdvertisePeerURLs()),
+	)
+	return ""
+}
+
+func (cfg *Config) IsNewCluster() bool { return cfg.ClusterState == ClusterStateFlagNew }
+func (cfg *Config) ElectionTicks() int { return int(cfg.ElectionMs / cfg.TickMs) }
+
+func (cfg *Config) V2DeprecationEffective() config.V2DeprecationEnum {
+	if cfg.V2Deprecation == "" {
+		return config.V2DeprDefault
+	}
+	return cfg.V2Deprecation
+}
+
+func (cfg *Config) defaultPeerHost() bool {
+	return len(cfg.AdvertisePeerUrls) == 1 && cfg.AdvertisePeerUrls[0].String() == DefaultInitialAdvertisePeerURLs
+}
+
+func (cfg *Config) defaultClientHost() bool {
+	return len(cfg.AdvertiseClientUrls) == 1 && cfg.AdvertiseClientUrls[0].String() == DefaultAdvertiseClientURLs
+}
+
+func (cfg *Config) ClientSelfCert() (err error) {
+	if !cfg.ClientAutoTLS {
+		return nil
+	}
+	if !cfg.ClientTLSInfo.Empty() {
+		cfg.logger.Warn("ignoring client auto TLS since certs given")
+		return nil
+	}
+	chosts := make([]string, 0, len(cfg.ListenClientUrls)+len(cfg.ListenClientHttpUrls))
+	for _, u := range cfg.ListenClientUrls {
+		chosts = append(chosts, u.Host)
+	}
+	for _, u := range cfg.ListenClientHttpUrls {
+		chosts = append(chosts, u.Host)
+	}
+	cfg.ClientTLSInfo, err = transport.SelfCert(cfg.logger, filepath.Join(cfg.Dir, "fixtures", "client"), chosts, cfg.SelfSignedCertValidity)
+	if err != nil {
+		return err
+	}
+	return updateCipherSuites(&cfg.ClientTLSInfo, cfg.CipherSuites)
+}
+
+func (cfg *Config) PeerSelfCert() (err error) {
+	if !cfg.PeerAutoTLS {
+		return nil
+	}
+	if !cfg.PeerTLSInfo.Empty() {
+		cfg.logger.Warn("ignoring peer auto TLS since certs given")
+		return nil
+	}
+	phosts := make([]string, len(cfg.ListenPeerUrls))
+	for i, u := range cfg.ListenPeerUrls {
+		phosts[i] = u.Host
+	}
+	cfg.PeerTLSInfo, err = transport.SelfCert(cfg.logger, filepath.Join(cfg.Dir, "fixtures", "peer"), phosts, cfg.SelfSignedCertValidity)
+	if err != nil {
+		return err
+	}
+	return updateCipherSuites(&cfg.PeerTLSInfo, cfg.CipherSuites)
+}
+
+// UpdateDefaultClusterFromName updates cluster advertise URLs with, if available, default host,
+// if advertise URLs are default values(localhost:2379,2380) AND if listen URL is 0.0.0.0.
+// e.g. advertise peer URL localhost:2380 or listen peer URL 0.0.0.0:2380
+// then the advertise peer host would be updated with machine's default host,
+// while keeping the listen URL's port.
+// User can work around this by explicitly setting URL with 127.0.0.1.
+// It returns the default hostname, if used, and the error, if any, from getting the machine's default host.
+// TODO: check whether fields are set instead of whether fields have default value
+func (cfg *Config) UpdateDefaultClusterFromName(defaultInitialCluster string) (string, error) {
+	if defaultHostname == "" || defaultHostStatus != nil {
+		// update 'initial-cluster' when only the name is specified (e.g. 'etcd --name=abc')
+		if cfg.Name != DefaultName && cfg.InitialCluster == defaultInitialCluster {
+			cfg.InitialCluster = cfg.InitialClusterFromName(cfg.Name)
+		}
+		return "", defaultHostStatus
+	}
+
+	used := false
+	pip, pport := cfg.ListenPeerUrls[0].Hostname(), cfg.ListenPeerUrls[0].Port()
+	if cfg.defaultPeerHost() && pip == "0.0.0.0" {
+		cfg.AdvertisePeerUrls[0] = url.URL{Scheme: cfg.AdvertisePeerUrls[0].Scheme, Host: fmt.Sprintf("%s:%s", defaultHostname, pport)}
+		used = true
+	}
+	// update 'initial-cluster' when only the name is specified (e.g. 'etcd --name=abc')
+	if cfg.Name != DefaultName && cfg.InitialCluster == defaultInitialCluster {
+		cfg.InitialCluster = cfg.InitialClusterFromName(cfg.Name)
+	}
+
+	cip, cport := cfg.ListenClientUrls[0].Hostname(), cfg.ListenClientUrls[0].Port()
+	if cfg.defaultClientHost() && cip == "0.0.0.0" {
+		cfg.AdvertiseClientUrls[0] = url.URL{Scheme: cfg.AdvertiseClientUrls[0].Scheme, Host: fmt.Sprintf("%s:%s", defaultHostname, cport)}
+		used = true
+	}
+	dhost := defaultHostname
+	if !used {
+		dhost = ""
+	}
+	return dhost, defaultHostStatus
+}
+
+// checkBindURLs returns an error if any URL uses a domain name.
+func checkBindURLs(urls []url.URL) error {
+	for _, url := range urls {
+		if url.Scheme == "unix" || url.Scheme == "unixs" {
+			continue
+		}
+		host, _, err := net.SplitHostPort(url.Host)
+		if err != nil {
+			return err
+		}
+		if host == "localhost" {
+			// special case for local address
+			// TODO: support /etc/hosts ?
+			continue
+		}
+		if net.ParseIP(host) == nil {
+			return fmt.Errorf("expected IP in URL for binding (%s)", url.String())
+		}
+	}
+	return nil
+}
+
+func checkHostURLs(urls []url.URL) error {
+	for _, url := range urls {
+		host, _, err := net.SplitHostPort(url.Host)
+		if err != nil {
+			return err
+		}
+		if host == "" {
+			return fmt.Errorf("unexpected empty host (%s)", url.String())
+		}
+	}
+	return nil
+}
+
+func (cfg *Config) getAdvertisePeerURLs() (ss []string) {
+	ss = make([]string, len(cfg.AdvertisePeerUrls))
+	for i := range cfg.AdvertisePeerUrls {
+		ss[i] = cfg.AdvertisePeerUrls[i].String()
+	}
+	return ss
+}
+
+func (cfg *Config) getListenPeerURLs() (ss []string) {
+	ss = make([]string, len(cfg.ListenPeerUrls))
+	for i := range cfg.ListenPeerUrls {
+		ss[i] = cfg.ListenPeerUrls[i].String()
+	}
+	return ss
+}
+
+func (cfg *Config) getAdvertiseClientURLs() (ss []string) {
+	ss = make([]string, len(cfg.AdvertiseClientUrls))
+	for i := range cfg.AdvertiseClientUrls {
+		ss[i] = cfg.AdvertiseClientUrls[i].String()
+	}
+	return ss
+}
+
+func (cfg *Config) getListenClientURLs() (ss []string) {
+	ss = make([]string, len(cfg.ListenClientUrls))
+	for i := range cfg.ListenClientUrls {
+		ss[i] = cfg.ListenClientUrls[i].String()
+	}
+	return ss
+}
+
+func (cfg *Config) getMetricsURLs() (ss []string) {
+	ss = make([]string, len(cfg.ListenMetricsUrls))
+	for i := range cfg.ListenMetricsUrls {
+		ss[i] = cfg.ListenMetricsUrls[i].String()
+	}
+	return ss
+}
+
+func parseBackendFreelistType(freelistType string) bolt.FreelistType {
+	if freelistType == freelistArrayType {
+		return bolt.FreelistArrayType
+	}
+
+	return bolt.FreelistMapType
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/embed/config_logging.go b/vendor/go.etcd.io/etcd/server/v3/embed/config_logging.go
new file mode 100644
index 0000000..c9da626
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/embed/config_logging.go
@@ -0,0 +1,282 @@
+// Copyright 2018 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package embed
+
+import (
+	"crypto/tls"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"net/url"
+	"os"
+
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
+	"go.uber.org/zap/zapgrpc"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/grpclog"
+	"gopkg.in/natefinch/lumberjack.v2"
+
+	"go.etcd.io/etcd/client/pkg/v3/logutil"
+)
+
+// GetLogger returns the logger.
+func (cfg *Config) GetLogger() *zap.Logger {
+	cfg.loggerMu.RLock()
+	l := cfg.logger
+	cfg.loggerMu.RUnlock()
+	return l
+}
+
+// setupLogging initializes etcd logging.
+// Must be called after flag parsing or finishing configuring embed.Config.
+func (cfg *Config) setupLogging() error {
+	switch cfg.Logger {
+	case "capnslog": // removed in v3.5
+		return fmt.Errorf("--logger=capnslog is removed in v3.5")
+
+	case "zap":
+		if len(cfg.LogOutputs) == 0 {
+			cfg.LogOutputs = []string{DefaultLogOutput}
+		}
+		if len(cfg.LogOutputs) > 1 {
+			for _, v := range cfg.LogOutputs {
+				if v == DefaultLogOutput {
+					return fmt.Errorf("multi logoutput for %q is not supported yet", DefaultLogOutput)
+				}
+			}
+		}
+		if cfg.EnableLogRotation {
+			if err := setupLogRotation(cfg.LogOutputs, cfg.LogRotationConfigJSON); err != nil {
+				return err
+			}
+		}
+
+		outputPaths, errOutputPaths := make([]string, 0), make([]string, 0)
+		isJournal := false
+		for _, v := range cfg.LogOutputs {
+			switch v {
+			case DefaultLogOutput:
+				outputPaths = append(outputPaths, StdErrLogOutput)
+				errOutputPaths = append(errOutputPaths, StdErrLogOutput)
+
+			case JournalLogOutput:
+				isJournal = true
+
+			case StdErrLogOutput:
+				outputPaths = append(outputPaths, StdErrLogOutput)
+				errOutputPaths = append(errOutputPaths, StdErrLogOutput)
+
+			case StdOutLogOutput:
+				outputPaths = append(outputPaths, StdOutLogOutput)
+				errOutputPaths = append(errOutputPaths, StdOutLogOutput)
+
+			default:
+				var path string
+				if cfg.EnableLogRotation {
+					// append rotate scheme to logs managed by lumberjack log rotation
+					if v[0:1] == "/" {
+						path = fmt.Sprintf("rotate:/%%2F%s", v[1:])
+					} else {
+						path = fmt.Sprintf("rotate:/%s", v)
+					}
+				} else {
+					path = v
+				}
+				outputPaths = append(outputPaths, path)
+				errOutputPaths = append(errOutputPaths, path)
+			}
+		}
+
+		if !isJournal {
+			copied := logutil.DefaultZapLoggerConfig
+			copied.OutputPaths = outputPaths
+			copied.ErrorOutputPaths = errOutputPaths
+			copied = logutil.MergeOutputPaths(copied)
+			copied.Level = zap.NewAtomicLevelAt(logutil.ConvertToZapLevel(cfg.LogLevel))
+			encoding, err := logutil.ConvertToZapFormat(cfg.LogFormat)
+			if err != nil {
+				return err
+			}
+			copied.Encoding = encoding
+			if cfg.ZapLoggerBuilder == nil {
+				lg, err := copied.Build()
+				if err != nil {
+					return err
+				}
+				cfg.ZapLoggerBuilder = NewZapLoggerBuilder(lg)
+			}
+		} else {
+			if len(cfg.LogOutputs) > 1 {
+				for _, v := range cfg.LogOutputs {
+					if v != DefaultLogOutput {
+						return fmt.Errorf("running with systemd/journal but other '--log-outputs' values (%q) are configured with 'default'; override 'default' value with something else", cfg.LogOutputs)
+					}
+				}
+			}
+
+			// use stderr as fallback
+			syncer, lerr := getJournalWriteSyncer()
+			if lerr != nil {
+				return lerr
+			}
+
+			lvl := zap.NewAtomicLevelAt(logutil.ConvertToZapLevel(cfg.LogLevel))
+
+			var encoder zapcore.Encoder
+			encoding, err := logutil.ConvertToZapFormat(cfg.LogFormat)
+			if err != nil {
+				return err
+			}
+
+			if encoding == logutil.ConsoleLogFormat {
+				encoder = zapcore.NewConsoleEncoder(logutil.DefaultZapLoggerConfig.EncoderConfig)
+			} else {
+				encoder = zapcore.NewJSONEncoder(logutil.DefaultZapLoggerConfig.EncoderConfig)
+			}
+
+			// WARN: do not change field names in encoder config
+			// journald logging writer assumes field names of "level" and "caller"
+			cr := zapcore.NewCore(
+				encoder,
+				syncer,
+				lvl,
+			)
+			if cfg.ZapLoggerBuilder == nil {
+				cfg.ZapLoggerBuilder = NewZapLoggerBuilder(zap.New(cr, zap.AddCaller(), zap.ErrorOutput(syncer)))
+			}
+		}
+
+		err := cfg.ZapLoggerBuilder(cfg)
+		if err != nil {
+			return err
+		}
+
+		logTLSHandshakeFailureFunc := func(msg string) func(conn *tls.Conn, err error) {
+			return func(conn *tls.Conn, err error) {
+				state := conn.ConnectionState()
+				remoteAddr := conn.RemoteAddr().String()
+				serverName := state.ServerName
+				if len(state.PeerCertificates) > 0 {
+					cert := state.PeerCertificates[0]
+					ips := make([]string, len(cert.IPAddresses))
+					for i := range cert.IPAddresses {
+						ips[i] = cert.IPAddresses[i].String()
+					}
+					cfg.logger.Warn(
+						msg,
+						zap.String("remote-addr", remoteAddr),
+						zap.String("server-name", serverName),
+						zap.Strings("ip-addresses", ips),
+						zap.Strings("dns-names", cert.DNSNames),
+						zap.Error(err),
+					)
+				} else {
+					cfg.logger.Warn(
+						msg,
+						zap.String("remote-addr", remoteAddr),
+						zap.String("server-name", serverName),
+						zap.Error(err),
+					)
+				}
+			}
+		}
+
+		cfg.ClientTLSInfo.HandshakeFailure = logTLSHandshakeFailureFunc("rejected connection on client endpoint")
+		cfg.PeerTLSInfo.HandshakeFailure = logTLSHandshakeFailureFunc("rejected connection on peer endpoint")
+
+	default:
+		return fmt.Errorf("unknown logger option %q", cfg.Logger)
+	}
+
+	return nil
+}
+
+// NewZapLoggerBuilder generates a zap logger builder that sets given logger
+// for embedded etcd.
+func NewZapLoggerBuilder(lg *zap.Logger) func(*Config) error {
+	return func(cfg *Config) error {
+		cfg.loggerMu.Lock()
+		defer cfg.loggerMu.Unlock()
+		cfg.logger = lg
+		return nil
+	}
+}
+
+// SetupGlobalLoggers configures 'global' loggers (grpc, zapGlobal) based on the cfg.
+//
+// The method is not executed by embed server by default (since 3.5) to
+// enable setups where grpc/zap.Global logging is configured independently
+// or spans separate lifecycle (like in tests).
+func (cfg *Config) SetupGlobalLoggers() {
+	lg := cfg.GetLogger()
+	if lg != nil {
+		if cfg.LogLevel == "debug" {
+			grpc.EnableTracing = true
+			grpclog.SetLoggerV2(zapgrpc.NewLogger(lg))
+		} else {
+			grpclog.SetLoggerV2(grpclog.NewLoggerV2(io.Discard, os.Stderr, os.Stderr))
+		}
+		zap.ReplaceGlobals(lg)
+	}
+}
+
+type logRotationConfig struct {
+	*lumberjack.Logger
+}
+
+// Sync implements zap.Sink
+func (logRotationConfig) Sync() error { return nil }
+
+// setupLogRotation initializes log rotation for a single file path target.
+func setupLogRotation(logOutputs []string, logRotateConfigJSON string) error {
+	var logRotationCfg logRotationConfig
+	outputFilePaths := 0
+	for _, v := range logOutputs {
+		switch v {
+		case DefaultLogOutput, StdErrLogOutput, StdOutLogOutput:
+			continue
+		default:
+			outputFilePaths++
+		}
+	}
+	// log rotation requires file target
+	if len(logOutputs) == 1 && outputFilePaths == 0 {
+		return ErrLogRotationInvalidLogOutput
+	}
+	// support max 1 file target for log rotation
+	if outputFilePaths > 1 {
+		return ErrLogRotationInvalidLogOutput
+	}
+
+	if err := json.Unmarshal([]byte(logRotateConfigJSON), &logRotationCfg); err != nil {
+		var unmarshalTypeError *json.UnmarshalTypeError
+		var syntaxError *json.SyntaxError
+		switch {
+		case errors.As(err, &syntaxError):
+			return fmt.Errorf("improperly formatted log rotation config: %w", err)
+		case errors.As(err, &unmarshalTypeError):
+			return fmt.Errorf("invalid log rotation config: %w", err)
+		default:
+			return fmt.Errorf("fail to unmarshal log rotation config: %w", err)
+		}
+	}
+	zap.RegisterSink("rotate", func(u *url.URL) (zap.Sink, error) {
+		logRotationCfg.Filename = u.Path[1:]
+		return &logRotationCfg, nil
+	})
+	return nil
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/embed/config_logging_journal_unix.go b/vendor/go.etcd.io/etcd/server/v3/embed/config_logging_journal_unix.go
new file mode 100644
index 0000000..478dc65
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/embed/config_logging_journal_unix.go
@@ -0,0 +1,35 @@
+// Copyright 2018 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build !windows
+
+package embed
+
+import (
+	"fmt"
+	"os"
+
+	"go.uber.org/zap/zapcore"
+
+	"go.etcd.io/etcd/client/pkg/v3/logutil"
+)
+
+// use stderr as fallback
+func getJournalWriteSyncer() (zapcore.WriteSyncer, error) {
+	jw, err := logutil.NewJournalWriter(os.Stderr)
+	if err != nil {
+		return nil, fmt.Errorf("can't find journal (%w)", err)
+	}
+	return zapcore.AddSync(jw), nil
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/embed/config_logging_journal_windows.go b/vendor/go.etcd.io/etcd/server/v3/embed/config_logging_journal_windows.go
new file mode 100644
index 0000000..90dfad9
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/embed/config_logging_journal_windows.go
@@ -0,0 +1,27 @@
+// Copyright 2018 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build windows
+
+package embed
+
+import (
+	"os"
+
+	"go.uber.org/zap/zapcore"
+)
+
+func getJournalWriteSyncer() (zapcore.WriteSyncer, error) {
+	return zapcore.AddSync(os.Stderr), nil
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/embed/config_tracing.go b/vendor/go.etcd.io/etcd/server/v3/embed/config_tracing.go
new file mode 100644
index 0000000..0ca90fd
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/embed/config_tracing.go
@@ -0,0 +1,138 @@
+// Copyright 2021 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package embed
+
+import (
+	"context"
+	"fmt"
+
+	"go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc"
+	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc"
+	"go.opentelemetry.io/otel/propagation"
+	"go.opentelemetry.io/otel/sdk/resource"
+	tracesdk "go.opentelemetry.io/otel/sdk/trace"
+	semconv "go.opentelemetry.io/otel/semconv/v1.17.0"
+	"go.uber.org/zap"
+)
+
+const maxSamplingRatePerMillion = 1000000
+
+func validateTracingConfig(samplingRate int) error {
+	if samplingRate < 0 {
+		return fmt.Errorf("tracing sampling rate must be positive")
+	}
+	if samplingRate > maxSamplingRatePerMillion {
+		return fmt.Errorf("tracing sampling rate must be less than %d", maxSamplingRatePerMillion)
+	}
+
+	return nil
+}
+
+type tracingExporter struct {
+	exporter tracesdk.SpanExporter
+	opts     []otelgrpc.Option
+	provider *tracesdk.TracerProvider
+}
+
+func newTracingExporter(ctx context.Context, cfg *Config) (*tracingExporter, error) {
+	exporter, err := otlptracegrpc.New(ctx,
+		otlptracegrpc.WithInsecure(),
+		otlptracegrpc.WithEndpoint(cfg.DistributedTracingAddress),
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	res, err := resource.New(ctx,
+		resource.WithAttributes(
+			semconv.ServiceNameKey.String(cfg.DistributedTracingServiceName),
+		),
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	if resWithIDKey := determineResourceWithIDKey(cfg.DistributedTracingServiceInstanceID); resWithIDKey != nil {
+		// Merge resources into a new
+		// resource in case of duplicates.
+		res, err = resource.Merge(res, resWithIDKey)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	traceProvider := tracesdk.NewTracerProvider(
+		tracesdk.WithBatcher(exporter),
+		tracesdk.WithResource(res),
+		tracesdk.WithSampler(
+			tracesdk.ParentBased(determineSampler(cfg.DistributedTracingSamplingRatePerMillion)),
+		),
+	)
+
+	options := []otelgrpc.Option{
+		otelgrpc.WithPropagators(
+			propagation.NewCompositeTextMapPropagator(
+				propagation.TraceContext{},
+				propagation.Baggage{},
+			),
+		),
+		otelgrpc.WithTracerProvider(
+			traceProvider,
+		),
+	}
+
+	cfg.logger.Debug(
+		"distributed tracing enabled",
+		zap.String("address", cfg.DistributedTracingAddress),
+		zap.String("service-name", cfg.DistributedTracingServiceName),
+		zap.String("service-instance-id", cfg.DistributedTracingServiceInstanceID),
+		zap.Int("sampling-rate", cfg.DistributedTracingSamplingRatePerMillion),
+	)
+
+	return &tracingExporter{
+		exporter: exporter,
+		opts:     options,
+		provider: traceProvider,
+	}, nil
+}
+
+func (te *tracingExporter) Close(ctx context.Context) {
+	if te.provider != nil {
+		te.provider.Shutdown(ctx)
+	}
+	if te.exporter != nil {
+		te.exporter.Shutdown(ctx)
+	}
+}
+
+func determineSampler(samplingRate int) tracesdk.Sampler {
+	sampler := tracesdk.NeverSample()
+	if samplingRate == 0 {
+		return sampler
+	}
+	return tracesdk.TraceIDRatioBased(float64(samplingRate) / float64(maxSamplingRatePerMillion))
+}
+
+// As Tracing service Instance ID must be unique, it should
+// never use the empty default string value, it's set if
+// if it's a non empty string.
+func determineResourceWithIDKey(serviceInstanceID string) *resource.Resource {
+	if serviceInstanceID != "" {
+		return resource.NewSchemaless(
+			(semconv.ServiceInstanceIDKey.String(serviceInstanceID)),
+		)
+	}
+	return nil
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/embed/doc.go b/vendor/go.etcd.io/etcd/server/v3/embed/doc.go
new file mode 100644
index 0000000..3449855
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/embed/doc.go
@@ -0,0 +1,45 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/*
+Package embed provides bindings for embedding an etcd server in a program.
+
+Launch an embedded etcd server using the configuration defaults:
+
+	import (
+		"log"
+		"time"
+
+		"go.etcd.io/etcd/server/v3/embed"
+	)
+
+	func main() {
+		cfg := embed.NewConfig()
+		cfg.Dir = "default.etcd"
+		e, err := embed.StartEtcd(cfg)
+		if err != nil {
+			log.Fatal(err)
+		}
+		defer e.Close()
+		select {
+		case <-e.Server.ReadyNotify():
+			log.Printf("Server is ready!")
+		case <-time.After(60 * time.Second):
+			e.Server.Stop() // trigger a shutdown
+			log.Printf("Server took too long to start!")
+		}
+		log.Fatal(<-e.Err())
+	}
+*/
+package embed
diff --git a/vendor/go.etcd.io/etcd/server/v3/embed/etcd.go b/vendor/go.etcd.io/etcd/server/v3/embed/etcd.go
new file mode 100644
index 0000000..95c0d6d
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/embed/etcd.go
@@ -0,0 +1,952 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package embed
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	defaultLog "log"
+	"math"
+	"net"
+	"net/http"
+	"net/url"
+	"runtime"
+	"sort"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/soheilhy/cmux"
+	"go.uber.org/zap"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials/insecure"
+	"google.golang.org/grpc/keepalive"
+
+	"go.etcd.io/etcd/api/v3/version"
+	"go.etcd.io/etcd/client/pkg/v3/transport"
+	"go.etcd.io/etcd/client/pkg/v3/types"
+	"go.etcd.io/etcd/client/v3/credentials"
+	"go.etcd.io/etcd/pkg/v3/debugutil"
+	runtimeutil "go.etcd.io/etcd/pkg/v3/runtime"
+	"go.etcd.io/etcd/server/v3/config"
+	"go.etcd.io/etcd/server/v3/etcdserver"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/etcdhttp"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp"
+	"go.etcd.io/etcd/server/v3/features"
+	"go.etcd.io/etcd/server/v3/storage"
+	"go.etcd.io/etcd/server/v3/verify"
+)
+
+const (
+	// internal fd usage includes disk usage and transport usage.
+	// To read/write snapshot, snap pkg needs 1. In normal case, wal pkg needs
+	// at most 2 to read/lock/write WALs. One case that it needs to 2 is to
+	// read all logs after some snapshot index, which locates at the end of
+	// the second last and the head of the last. For purging, it needs to read
+	// directory, so it needs 1. For fd monitor, it needs 1.
+	// For transport, rafthttp builds two long-polling connections and at most
+	// four temporary connections with each member. There are at most 9 members
+	// in a cluster, so it should reserve 96.
+	// For the safety, we set the total reserved number to 150.
+	reservedInternalFDNum = 150
+)
+
+// Etcd contains a running etcd server and its listeners.
+type Etcd struct {
+	Peers   []*peerListener
+	Clients []net.Listener
+	// a map of contexts for the servers that serves client requests.
+	sctxs            map[string]*serveCtx
+	metricsListeners []net.Listener
+
+	tracingExporterShutdown func()
+
+	Server *etcdserver.EtcdServer
+
+	cfg Config
+
+	// closeOnce is to ensure `stopc` is closed only once, no matter
+	// how many times the Close() method is called.
+	closeOnce sync.Once
+	// stopc is used to notify the sub goroutines not to send
+	// any errors to `errc`.
+	stopc chan struct{}
+	// errc is used to receive error from sub goroutines (including
+	// client handler, peer handler and metrics handler). It's closed
+	// after all these sub goroutines exit (checked via `wg`). Writers
+	// should avoid writing after `stopc` is closed by selecting on
+	// reading from `stopc`.
+	errc chan error
+
+	// wg is used to track the lifecycle of all sub goroutines which
+	// need to send error back to the `errc`.
+	wg sync.WaitGroup
+}
+
+type peerListener struct {
+	net.Listener
+	serve func() error
+	close func(context.Context) error
+}
+
+// StartEtcd launches the etcd server and HTTP handlers for client/server communication.
+// The returned Etcd.Server is not guaranteed to have joined the cluster. Wait
+// on the Etcd.Server.ReadyNotify() channel to know when it completes and is ready for use.
+func StartEtcd(inCfg *Config) (e *Etcd, err error) {
+	if err = inCfg.Validate(); err != nil {
+		return nil, err
+	}
+	serving := false
+	e = &Etcd{cfg: *inCfg, stopc: make(chan struct{})}
+	cfg := &e.cfg
+	defer func() {
+		if e == nil || err == nil {
+			return
+		}
+		if !serving {
+			// errored before starting gRPC server for serveCtx.serversC
+			for _, sctx := range e.sctxs {
+				sctx.close()
+			}
+		}
+		e.Close()
+		e = nil
+	}()
+
+	if !cfg.SocketOpts.Empty() {
+		cfg.logger.Info(
+			"configuring socket options",
+			zap.Bool("reuse-address", cfg.SocketOpts.ReuseAddress),
+			zap.Bool("reuse-port", cfg.SocketOpts.ReusePort),
+		)
+	}
+	e.cfg.logger.Info(
+		"configuring peer listeners",
+		zap.Strings("listen-peer-urls", e.cfg.getListenPeerURLs()),
+	)
+	if e.Peers, err = configurePeerListeners(cfg); err != nil {
+		return e, err
+	}
+
+	e.cfg.logger.Info(
+		"configuring client listeners",
+		zap.Strings("listen-client-urls", e.cfg.getListenClientURLs()),
+	)
+	if e.sctxs, err = configureClientListeners(cfg); err != nil {
+		return e, err
+	}
+
+	for _, sctx := range e.sctxs {
+		e.Clients = append(e.Clients, sctx.l)
+	}
+
+	var (
+		urlsmap types.URLsMap
+		token   string
+	)
+	memberInitialized := true
+	if !isMemberInitialized(cfg) {
+		memberInitialized = false
+		urlsmap, token, err = cfg.PeerURLsMapAndToken("etcd")
+		if err != nil {
+			return e, fmt.Errorf("error setting up initial cluster: %w", err)
+		}
+	}
+
+	// AutoCompactionRetention defaults to "0" if not set.
+	if len(cfg.AutoCompactionRetention) == 0 {
+		cfg.AutoCompactionRetention = "0"
+	}
+	autoCompactionRetention, err := parseCompactionRetention(cfg.AutoCompactionMode, cfg.AutoCompactionRetention)
+	if err != nil {
+		return e, err
+	}
+
+	backendFreelistType := parseBackendFreelistType(cfg.BackendFreelistType)
+
+	srvcfg := config.ServerConfig{
+		Name:                              cfg.Name,
+		ClientURLs:                        cfg.AdvertiseClientUrls,
+		PeerURLs:                          cfg.AdvertisePeerUrls,
+		DataDir:                           cfg.Dir,
+		DedicatedWALDir:                   cfg.WalDir,
+		SnapshotCount:                     cfg.SnapshotCount,
+		SnapshotCatchUpEntries:            cfg.SnapshotCatchUpEntries,
+		MaxSnapFiles:                      cfg.MaxSnapFiles,
+		MaxWALFiles:                       cfg.MaxWalFiles,
+		InitialPeerURLsMap:                urlsmap,
+		InitialClusterToken:               token,
+		DiscoveryURL:                      cfg.Durl,
+		DiscoveryProxy:                    cfg.Dproxy,
+		DiscoveryCfg:                      cfg.DiscoveryCfg,
+		NewCluster:                        cfg.IsNewCluster(),
+		PeerTLSInfo:                       cfg.PeerTLSInfo,
+		TickMs:                            cfg.TickMs,
+		ElectionTicks:                     cfg.ElectionTicks(),
+		InitialElectionTickAdvance:        cfg.InitialElectionTickAdvance,
+		AutoCompactionRetention:           autoCompactionRetention,
+		AutoCompactionMode:                cfg.AutoCompactionMode,
+		QuotaBackendBytes:                 cfg.QuotaBackendBytes,
+		BackendBatchLimit:                 cfg.BackendBatchLimit,
+		BackendFreelistType:               backendFreelistType,
+		BackendBatchInterval:              cfg.BackendBatchInterval,
+		MaxTxnOps:                         cfg.MaxTxnOps,
+		MaxRequestBytes:                   cfg.MaxRequestBytes,
+		MaxConcurrentStreams:              cfg.MaxConcurrentStreams,
+		SocketOpts:                        cfg.SocketOpts,
+		StrictReconfigCheck:               cfg.StrictReconfigCheck,
+		ClientCertAuthEnabled:             cfg.ClientTLSInfo.ClientCertAuth,
+		AuthToken:                         cfg.AuthToken,
+		BcryptCost:                        cfg.BcryptCost,
+		TokenTTL:                          cfg.AuthTokenTTL,
+		CORS:                              cfg.CORS,
+		HostWhitelist:                     cfg.HostWhitelist,
+		CorruptCheckTime:                  cfg.CorruptCheckTime,
+		CompactHashCheckTime:              cfg.CompactHashCheckTime,
+		PreVote:                           cfg.PreVote,
+		Logger:                            cfg.logger,
+		ForceNewCluster:                   cfg.ForceNewCluster,
+		EnableGRPCGateway:                 cfg.EnableGRPCGateway,
+		EnableDistributedTracing:          cfg.EnableDistributedTracing,
+		UnsafeNoFsync:                     cfg.UnsafeNoFsync,
+		CompactionBatchLimit:              cfg.CompactionBatchLimit,
+		CompactionSleepInterval:           cfg.CompactionSleepInterval,
+		WatchProgressNotifyInterval:       cfg.WatchProgressNotifyInterval,
+		DowngradeCheckTime:                cfg.DowngradeCheckTime,
+		WarningApplyDuration:              cfg.WarningApplyDuration,
+		WarningUnaryRequestDuration:       cfg.WarningUnaryRequestDuration,
+		MemoryMlock:                       cfg.MemoryMlock,
+		BootstrapDefragThresholdMegabytes: cfg.BootstrapDefragThresholdMegabytes,
+		MaxLearners:                       cfg.MaxLearners,
+		V2Deprecation:                     cfg.V2DeprecationEffective(),
+		ExperimentalLocalAddress:          cfg.InferLocalAddr(),
+		ServerFeatureGate:                 cfg.ServerFeatureGate,
+		Metrics:                           cfg.Metrics,
+	}
+
+	if srvcfg.EnableDistributedTracing {
+		tctx := context.Background()
+		tracingExporter, terr := newTracingExporter(tctx, cfg)
+		if terr != nil {
+			return e, terr
+		}
+		e.tracingExporterShutdown = func() {
+			tracingExporter.Close(tctx)
+		}
+		srvcfg.TracerOptions = tracingExporter.opts
+
+		e.cfg.logger.Info(
+			"distributed tracing setup enabled",
+		)
+	}
+
+	srvcfg.PeerTLSInfo.LocalAddr = srvcfg.ExperimentalLocalAddress
+
+	print(e.cfg.logger, *cfg, srvcfg, memberInitialized)
+
+	if e.Server, err = etcdserver.NewServer(srvcfg); err != nil {
+		return e, err
+	}
+
+	// buffer channel so goroutines on closed connections won't wait forever
+	e.errc = make(chan error, len(e.Peers)+len(e.Clients)+2*len(e.sctxs))
+
+	// newly started member ("memberInitialized==false")
+	// does not need corruption check
+	if memberInitialized && srvcfg.ServerFeatureGate.Enabled(features.InitialCorruptCheck) {
+		if err = e.Server.CorruptionChecker().InitialCheck(); err != nil {
+			// set "EtcdServer" to nil, so that it does not block on "EtcdServer.Close()"
+			// (nothing to close since rafthttp transports have not been started)
+
+			e.cfg.logger.Error("checkInitialHashKV failed", zap.Error(err))
+			e.Server.Cleanup()
+			e.Server = nil
+			return e, err
+		}
+	}
+	e.Server.Start()
+
+	e.servePeers()
+
+	e.serveClients()
+
+	if err = e.serveMetrics(); err != nil {
+		return e, err
+	}
+
+	e.cfg.logger.Info(
+		"now serving peer/client/metrics",
+		zap.String("local-member-id", e.Server.MemberID().String()),
+		zap.Strings("initial-advertise-peer-urls", e.cfg.getAdvertisePeerURLs()),
+		zap.Strings("listen-peer-urls", e.cfg.getListenPeerURLs()),
+		zap.Strings("advertise-client-urls", e.cfg.getAdvertiseClientURLs()),
+		zap.Strings("listen-client-urls", e.cfg.getListenClientURLs()),
+		zap.Strings("listen-metrics-urls", e.cfg.getMetricsURLs()),
+	)
+	serving = true
+	return e, nil
+}
+
+func print(lg *zap.Logger, ec Config, sc config.ServerConfig, memberInitialized bool) {
+	cors := make([]string, 0, len(ec.CORS))
+	for v := range ec.CORS {
+		cors = append(cors, v)
+	}
+	sort.Strings(cors)
+
+	hss := make([]string, 0, len(ec.HostWhitelist))
+	for v := range ec.HostWhitelist {
+		hss = append(hss, v)
+	}
+	sort.Strings(hss)
+
+	quota := ec.QuotaBackendBytes
+	if quota == 0 {
+		quota = storage.DefaultQuotaBytes
+	}
+
+	lg.Info(
+		"starting an etcd server",
+		zap.String("etcd-version", version.Version),
+		zap.String("git-sha", version.GitSHA),
+		zap.String("go-version", runtime.Version()),
+		zap.String("go-os", runtime.GOOS),
+		zap.String("go-arch", runtime.GOARCH),
+		zap.Int("max-cpu-set", runtime.GOMAXPROCS(0)),
+		zap.Int("max-cpu-available", runtime.NumCPU()),
+		zap.Bool("member-initialized", memberInitialized),
+		zap.String("name", sc.Name),
+		zap.String("data-dir", sc.DataDir),
+		zap.String("wal-dir", ec.WalDir),
+		zap.String("wal-dir-dedicated", sc.DedicatedWALDir),
+		zap.String("member-dir", sc.MemberDir()),
+		zap.Bool("force-new-cluster", sc.ForceNewCluster),
+		zap.String("heartbeat-interval", fmt.Sprintf("%v", time.Duration(sc.TickMs)*time.Millisecond)),
+		zap.String("election-timeout", fmt.Sprintf("%v", time.Duration(sc.ElectionTicks*int(sc.TickMs))*time.Millisecond)),
+		zap.Bool("initial-election-tick-advance", sc.InitialElectionTickAdvance),
+		zap.Uint64("snapshot-count", sc.SnapshotCount),
+		zap.Uint("max-wals", sc.MaxWALFiles),
+		zap.Uint("max-snapshots", sc.MaxSnapFiles),
+		zap.Uint64("snapshot-catchup-entries", sc.SnapshotCatchUpEntries),
+		zap.Strings("initial-advertise-peer-urls", ec.getAdvertisePeerURLs()),
+		zap.Strings("listen-peer-urls", ec.getListenPeerURLs()),
+		zap.Strings("advertise-client-urls", ec.getAdvertiseClientURLs()),
+		zap.Strings("listen-client-urls", ec.getListenClientURLs()),
+		zap.Strings("listen-metrics-urls", ec.getMetricsURLs()),
+		zap.String("experimental-local-address", sc.ExperimentalLocalAddress),
+		zap.Strings("cors", cors),
+		zap.Strings("host-whitelist", hss),
+		zap.String("initial-cluster", sc.InitialPeerURLsMap.String()),
+		zap.String("initial-cluster-state", ec.ClusterState),
+		zap.String("initial-cluster-token", sc.InitialClusterToken),
+		zap.Int64("quota-backend-bytes", quota),
+		zap.Uint("max-request-bytes", sc.MaxRequestBytes),
+		zap.Uint32("max-concurrent-streams", sc.MaxConcurrentStreams),
+
+		zap.Bool("pre-vote", sc.PreVote),
+		zap.String(ServerFeatureGateFlagName, sc.ServerFeatureGate.String()),
+		zap.Bool("initial-corrupt-check", sc.InitialCorruptCheck),
+		zap.String("corrupt-check-time-interval", sc.CorruptCheckTime.String()),
+		zap.Duration("compact-check-time-interval", sc.CompactHashCheckTime),
+		zap.String("auto-compaction-mode", sc.AutoCompactionMode),
+		zap.Duration("auto-compaction-retention", sc.AutoCompactionRetention),
+		zap.String("auto-compaction-interval", sc.AutoCompactionRetention.String()),
+		zap.String("discovery-url", sc.DiscoveryURL),
+		zap.String("discovery-proxy", sc.DiscoveryProxy),
+
+		zap.String("discovery-token", sc.DiscoveryCfg.Token),
+		zap.String("discovery-endpoints", strings.Join(sc.DiscoveryCfg.Endpoints, ",")),
+		zap.String("discovery-dial-timeout", sc.DiscoveryCfg.DialTimeout.String()),
+		zap.String("discovery-request-timeout", sc.DiscoveryCfg.RequestTimeout.String()),
+		zap.String("discovery-keepalive-time", sc.DiscoveryCfg.KeepAliveTime.String()),
+		zap.String("discovery-keepalive-timeout", sc.DiscoveryCfg.KeepAliveTimeout.String()),
+		zap.Bool("discovery-insecure-transport", sc.DiscoveryCfg.Secure.InsecureTransport),
+		zap.Bool("discovery-insecure-skip-tls-verify", sc.DiscoveryCfg.Secure.InsecureSkipVerify),
+		zap.String("discovery-cert", sc.DiscoveryCfg.Secure.Cert),
+		zap.String("discovery-key", sc.DiscoveryCfg.Secure.Key),
+		zap.String("discovery-cacert", sc.DiscoveryCfg.Secure.Cacert),
+		zap.String("discovery-user", sc.DiscoveryCfg.Auth.Username),
+
+		zap.String("downgrade-check-interval", sc.DowngradeCheckTime.String()),
+		zap.Int("max-learners", sc.MaxLearners),
+
+		zap.String("v2-deprecation", string(ec.V2Deprecation)),
+	)
+}
+
+// Config returns the current configuration.
+func (e *Etcd) Config() Config {
+	return e.cfg
+}
+
+// Close gracefully shuts down all servers/listeners.
+// Client requests will be terminated with request timeout.
+// After timeout, enforce remaning requests be closed immediately.
+//
+// The rough workflow to shut down etcd:
+//  1. close the `stopc` channel, so that all error handlers (child
+//     goroutines) won't send back any errors anymore;
+//  2. stop the http and grpc servers gracefully, within request timeout;
+//  3. close all client and metrics listeners, so that etcd server
+//     stops receiving any new connection;
+//  4. call the cancel function to close the gateway context, so that
+//     all gateway connections are closed.
+//  5. stop etcd server gracefully, and ensure the main raft loop
+//     goroutine is stopped;
+//  6. stop all peer listeners, so that it stops receiving peer connections
+//     and messages (wait up to 1-second);
+//  7. wait for all child goroutines (i.e. client handlers, peer handlers
+//     and metrics handlers) to exit;
+//  8. close the `errc` channel to release the resource. Note that it's only
+//     safe to close the `errc` after step 7 above is done, otherwise the
+//     child goroutines may send errors back to already closed `errc` channel.
+func (e *Etcd) Close() {
+	fields := []zap.Field{
+		zap.String("name", e.cfg.Name),
+		zap.String("data-dir", e.cfg.Dir),
+		zap.Strings("advertise-peer-urls", e.cfg.getAdvertisePeerURLs()),
+		zap.Strings("advertise-client-urls", e.cfg.getAdvertiseClientURLs()),
+	}
+	lg := e.GetLogger()
+	lg.Info("closing etcd server", fields...)
+	defer func() {
+		lg.Info("closed etcd server", fields...)
+		verify.MustVerifyIfEnabled(verify.Config{
+			Logger:     lg,
+			DataDir:    e.cfg.Dir,
+			ExactIndex: false,
+		})
+		lg.Sync()
+	}()
+
+	e.closeOnce.Do(func() {
+		close(e.stopc)
+	})
+
+	// close client requests with request timeout
+	timeout := 2 * time.Second
+	if e.Server != nil {
+		timeout = e.Server.Cfg.ReqTimeout()
+	}
+	for _, sctx := range e.sctxs {
+		for ss := range sctx.serversC {
+			ctx, cancel := context.WithTimeout(context.Background(), timeout)
+			stopServers(ctx, ss)
+			cancel()
+		}
+	}
+
+	for _, sctx := range e.sctxs {
+		sctx.cancel()
+	}
+
+	for i := range e.Clients {
+		if e.Clients[i] != nil {
+			e.Clients[i].Close()
+		}
+	}
+
+	for i := range e.metricsListeners {
+		e.metricsListeners[i].Close()
+	}
+
+	// shutdown tracing exporter
+	if e.tracingExporterShutdown != nil {
+		e.tracingExporterShutdown()
+	}
+
+	// close rafthttp transports
+	if e.Server != nil {
+		e.Server.Stop()
+	}
+
+	// close all idle connections in peer handler (wait up to 1-second)
+	for i := range e.Peers {
+		if e.Peers[i] != nil && e.Peers[i].close != nil {
+			ctx, cancel := context.WithTimeout(context.Background(), time.Second)
+			e.Peers[i].close(ctx)
+			cancel()
+		}
+	}
+	if e.errc != nil {
+		e.wg.Wait()
+		close(e.errc)
+	}
+}
+
+func stopServers(ctx context.Context, ss *servers) {
+	// first, close the http.Server
+	if ss.http != nil {
+		ss.http.Shutdown(ctx)
+	}
+	if ss.grpc == nil {
+		return
+	}
+	// do not grpc.Server.GracefulStop when grpc runs under http server
+	// See https://github.com/grpc/grpc-go/issues/1384#issuecomment-317124531
+	// and https://github.com/etcd-io/etcd/issues/8916
+	if ss.secure && ss.http != nil {
+		ss.grpc.Stop()
+		return
+	}
+
+	ch := make(chan struct{})
+	go func() {
+		defer close(ch)
+		// close listeners to stop accepting new connections,
+		// will block on any existing transports
+		ss.grpc.GracefulStop()
+	}()
+
+	// wait until all pending RPCs are finished
+	select {
+	case <-ch:
+	case <-ctx.Done():
+		// took too long, manually close open transports
+		// e.g. watch streams
+		ss.grpc.Stop()
+
+		// concurrent GracefulStop should be interrupted
+		<-ch
+	}
+}
+
+// Err - return channel used to report errors during etcd run/shutdown.
+// Since etcd 3.5 the channel is being closed when the etcd is over.
+func (e *Etcd) Err() <-chan error {
+	return e.errc
+}
+
+func configurePeerListeners(cfg *Config) (peers []*peerListener, err error) {
+	if err = updateCipherSuites(&cfg.PeerTLSInfo, cfg.CipherSuites); err != nil {
+		return nil, err
+	}
+	if err = cfg.PeerSelfCert(); err != nil {
+		cfg.logger.Fatal("failed to get peer self-signed certs", zap.Error(err))
+	}
+	updateMinMaxVersions(&cfg.PeerTLSInfo, cfg.TlsMinVersion, cfg.TlsMaxVersion)
+	if !cfg.PeerTLSInfo.Empty() {
+		cfg.logger.Info(
+			"starting with peer TLS",
+			zap.String("tls-info", fmt.Sprintf("%+v", cfg.PeerTLSInfo)),
+			zap.Strings("cipher-suites", cfg.CipherSuites),
+		)
+	}
+
+	peers = make([]*peerListener, len(cfg.ListenPeerUrls))
+	defer func() {
+		if err == nil {
+			return
+		}
+		for i := range peers {
+			if peers[i] != nil && peers[i].close != nil {
+				cfg.logger.Warn(
+					"closing peer listener",
+					zap.String("address", cfg.ListenPeerUrls[i].String()),
+					zap.Error(err),
+				)
+				ctx, cancel := context.WithTimeout(context.Background(), time.Second)
+				peers[i].close(ctx)
+				cancel()
+			}
+		}
+	}()
+
+	for i, u := range cfg.ListenPeerUrls {
+		if u.Scheme == "http" {
+			if !cfg.PeerTLSInfo.Empty() {
+				cfg.logger.Warn("scheme is HTTP while key and cert files are present; ignoring key and cert files", zap.String("peer-url", u.String()))
+			}
+			if cfg.PeerTLSInfo.ClientCertAuth {
+				cfg.logger.Warn("scheme is HTTP while --peer-client-cert-auth is enabled; ignoring client cert auth for this URL", zap.String("peer-url", u.String()))
+			}
+		}
+		peers[i] = &peerListener{close: func(context.Context) error { return nil }}
+		peers[i].Listener, err = transport.NewListenerWithOpts(u.Host, u.Scheme,
+			transport.WithTLSInfo(&cfg.PeerTLSInfo),
+			transport.WithSocketOpts(&cfg.SocketOpts),
+			transport.WithTimeout(rafthttp.ConnReadTimeout, rafthttp.ConnWriteTimeout),
+		)
+		if err != nil {
+			cfg.logger.Error("creating peer listener failed", zap.Error(err))
+			return nil, err
+		}
+		// once serve, overwrite with 'http.Server.Shutdown'
+		peers[i].close = func(context.Context) error {
+			return peers[i].Listener.Close()
+		}
+	}
+	return peers, nil
+}
+
+// configure peer handlers after rafthttp.Transport started
+func (e *Etcd) servePeers() {
+	ph := etcdhttp.NewPeerHandler(e.GetLogger(), e.Server)
+
+	for _, p := range e.Peers {
+		u := p.Listener.Addr().String()
+		m := cmux.New(p.Listener)
+		srv := &http.Server{
+			Handler:     ph,
+			ReadTimeout: 5 * time.Minute,
+			ErrorLog:    defaultLog.New(io.Discard, "", 0), // do not log user error
+		}
+		go srv.Serve(m.Match(cmux.Any()))
+		p.serve = func() error {
+			e.cfg.logger.Info(
+				"cmux::serve",
+				zap.String("address", u),
+			)
+			return m.Serve()
+		}
+		p.close = func(ctx context.Context) error {
+			// gracefully shutdown http.Server
+			// close open listeners, idle connections
+			// until context cancel or time-out
+			e.cfg.logger.Info(
+				"stopping serving peer traffic",
+				zap.String("address", u),
+			)
+			srv.Shutdown(ctx)
+			e.cfg.logger.Info(
+				"stopped serving peer traffic",
+				zap.String("address", u),
+			)
+			m.Close()
+			return nil
+		}
+	}
+
+	// start peer servers in a goroutine
+	for _, pl := range e.Peers {
+		l := pl
+		e.startHandler(func() error {
+			u := l.Addr().String()
+			e.cfg.logger.Info(
+				"serving peer traffic",
+				zap.String("address", u),
+			)
+			return l.serve()
+		})
+	}
+}
+
+func configureClientListeners(cfg *Config) (sctxs map[string]*serveCtx, err error) {
+	if err = updateCipherSuites(&cfg.ClientTLSInfo, cfg.CipherSuites); err != nil {
+		return nil, err
+	}
+	if err = cfg.ClientSelfCert(); err != nil {
+		cfg.logger.Fatal("failed to get client self-signed certs", zap.Error(err))
+	}
+	updateMinMaxVersions(&cfg.ClientTLSInfo, cfg.TlsMinVersion, cfg.TlsMaxVersion)
+	if cfg.EnablePprof {
+		cfg.logger.Info("pprof is enabled", zap.String("path", debugutil.HTTPPrefixPProf))
+	}
+
+	sctxs = make(map[string]*serveCtx)
+	for _, u := range append(cfg.ListenClientUrls, cfg.ListenClientHttpUrls...) {
+		if u.Scheme == "http" || u.Scheme == "unix" {
+			if !cfg.ClientTLSInfo.Empty() {
+				cfg.logger.Warn("scheme is http or unix while key and cert files are present; ignoring key and cert files", zap.String("client-url", u.String()))
+			}
+			if cfg.ClientTLSInfo.ClientCertAuth {
+				cfg.logger.Warn("scheme is http or unix while --client-cert-auth is enabled; ignoring client cert auth for this URL", zap.String("client-url", u.String()))
+			}
+		}
+		if (u.Scheme == "https" || u.Scheme == "unixs") && cfg.ClientTLSInfo.Empty() {
+			return nil, fmt.Errorf("TLS key/cert (--cert-file, --key-file) must be provided for client url %s with HTTPS scheme", u.String())
+		}
+	}
+
+	for _, u := range cfg.ListenClientUrls {
+		addr, secure, network := resolveURL(u)
+		sctx := sctxs[addr]
+		if sctx == nil {
+			sctx = newServeCtx(cfg.logger)
+			sctxs[addr] = sctx
+		}
+		sctx.secure = sctx.secure || secure
+		sctx.insecure = sctx.insecure || !secure
+		sctx.scheme = u.Scheme
+		sctx.addr = addr
+		sctx.network = network
+	}
+	for _, u := range cfg.ListenClientHttpUrls {
+		addr, secure, network := resolveURL(u)
+
+		sctx := sctxs[addr]
+		if sctx == nil {
+			sctx = newServeCtx(cfg.logger)
+			sctxs[addr] = sctx
+		} else if !sctx.httpOnly {
+			return nil, fmt.Errorf("cannot bind both --listen-client-urls and --listen-client-http-urls on the same url %s", u.String())
+		}
+		sctx.secure = sctx.secure || secure
+		sctx.insecure = sctx.insecure || !secure
+		sctx.scheme = u.Scheme
+		sctx.addr = addr
+		sctx.network = network
+		sctx.httpOnly = true
+	}
+
+	for _, sctx := range sctxs {
+		if sctx.l, err = transport.NewListenerWithOpts(sctx.addr, sctx.scheme,
+			transport.WithSocketOpts(&cfg.SocketOpts),
+			transport.WithSkipTLSInfoCheck(true),
+		); err != nil {
+			return nil, err
+		}
+		// net.Listener will rewrite ipv4 0.0.0.0 to ipv6 [::], breaking
+		// hosts that disable ipv6. So, use the address given by the user.
+
+		if fdLimit, fderr := runtimeutil.FDLimit(); fderr == nil {
+			if fdLimit <= reservedInternalFDNum {
+				cfg.logger.Fatal(
+					"file descriptor limit of etcd process is too low; please set higher",
+					zap.Uint64("limit", fdLimit),
+					zap.Int("recommended-limit", reservedInternalFDNum),
+				)
+			}
+			sctx.l = transport.LimitListener(sctx.l, int(fdLimit-reservedInternalFDNum))
+		}
+
+		defer func(sctx *serveCtx) {
+			if err == nil || sctx.l == nil {
+				return
+			}
+			sctx.l.Close()
+			cfg.logger.Warn(
+				"closing peer listener",
+				zap.String("address", sctx.addr),
+				zap.Error(err),
+			)
+		}(sctx)
+		for k := range cfg.UserHandlers {
+			sctx.userHandlers[k] = cfg.UserHandlers[k]
+		}
+		sctx.serviceRegister = cfg.ServiceRegister
+		if cfg.EnablePprof || cfg.LogLevel == "debug" {
+			sctx.registerPprof()
+		}
+		if cfg.LogLevel == "debug" {
+			sctx.registerTrace()
+		}
+	}
+	return sctxs, nil
+}
+
+func resolveURL(u url.URL) (addr string, secure bool, network string) {
+	addr = u.Host
+	network = "tcp"
+	if u.Scheme == "unix" || u.Scheme == "unixs" {
+		addr = u.Host + u.Path
+		network = "unix"
+	}
+	secure = u.Scheme == "https" || u.Scheme == "unixs"
+	return addr, secure, network
+}
+
+func (e *Etcd) serveClients() {
+	if !e.cfg.ClientTLSInfo.Empty() {
+		e.cfg.logger.Info(
+			"starting with client TLS",
+			zap.String("tls-info", fmt.Sprintf("%+v", e.cfg.ClientTLSInfo)),
+			zap.Strings("cipher-suites", e.cfg.CipherSuites),
+		)
+	}
+
+	// Start a client server goroutine for each listen address
+	mux := http.NewServeMux()
+	etcdhttp.HandleDebug(mux)
+	etcdhttp.HandleVersion(mux, e.Server)
+	etcdhttp.HandleMetrics(mux)
+	etcdhttp.HandleHealth(e.cfg.logger, mux, e.Server)
+
+	var gopts []grpc.ServerOption
+	if e.cfg.GRPCKeepAliveMinTime > time.Duration(0) {
+		gopts = append(gopts, grpc.KeepaliveEnforcementPolicy(keepalive.EnforcementPolicy{
+			MinTime:             e.cfg.GRPCKeepAliveMinTime,
+			PermitWithoutStream: false,
+		}))
+	}
+	if e.cfg.GRPCKeepAliveInterval > time.Duration(0) &&
+		e.cfg.GRPCKeepAliveTimeout > time.Duration(0) {
+		gopts = append(gopts, grpc.KeepaliveParams(keepalive.ServerParameters{
+			Time:    e.cfg.GRPCKeepAliveInterval,
+			Timeout: e.cfg.GRPCKeepAliveTimeout,
+		}))
+	}
+	gopts = append(gopts, e.cfg.GRPCAdditionalServerOptions...)
+
+	splitHTTP := false
+	for _, sctx := range e.sctxs {
+		if sctx.httpOnly {
+			splitHTTP = true
+		}
+	}
+
+	// start client servers in each goroutine
+	for _, sctx := range e.sctxs {
+		s := sctx
+		e.startHandler(func() error {
+			return s.serve(e.Server, &e.cfg.ClientTLSInfo, mux, e.errHandler, e.grpcGatewayDial(splitHTTP), splitHTTP, gopts...)
+		})
+	}
+}
+
+func (e *Etcd) grpcGatewayDial(splitHTTP bool) (grpcDial func(ctx context.Context) (*grpc.ClientConn, error)) {
+	if !e.cfg.EnableGRPCGateway {
+		return nil
+	}
+	sctx := e.pickGRPCGatewayServeContext(splitHTTP)
+	addr := sctx.addr
+	if network := sctx.network; network == "unix" {
+		// explicitly define unix network for gRPC socket support
+		addr = fmt.Sprintf("%s:%s", network, addr)
+	}
+	opts := []grpc.DialOption{grpc.WithDefaultCallOptions(grpc.MaxCallRecvMsgSize(math.MaxInt32))}
+	if sctx.secure {
+		tlscfg, tlsErr := e.cfg.ClientTLSInfo.ServerConfig()
+		if tlsErr != nil {
+			return func(ctx context.Context) (*grpc.ClientConn, error) {
+				return nil, tlsErr
+			}
+		}
+		dtls := tlscfg.Clone()
+		// trust local server
+		dtls.InsecureSkipVerify = true
+		opts = append(opts, grpc.WithTransportCredentials(credentials.NewTransportCredential(dtls)))
+	} else {
+		opts = append(opts, grpc.WithTransportCredentials(insecure.NewCredentials()))
+	}
+
+	return func(ctx context.Context) (*grpc.ClientConn, error) {
+		conn, err := grpc.DialContext(ctx, addr, opts...)
+		if err != nil {
+			sctx.lg.Error("grpc gateway failed to dial", zap.String("addr", addr), zap.Error(err))
+			return nil, err
+		}
+		return conn, err
+	}
+}
+
+func (e *Etcd) pickGRPCGatewayServeContext(splitHTTP bool) *serveCtx {
+	for _, sctx := range e.sctxs {
+		if !splitHTTP || !sctx.httpOnly {
+			return sctx
+		}
+	}
+	panic("Expect at least one context able to serve grpc")
+}
+
+var ErrMissingClientTLSInfoForMetricsURL = errors.New("client TLS key/cert (--cert-file, --key-file) must be provided for metrics secure url")
+
+func (e *Etcd) createMetricsListener(murl url.URL) (net.Listener, error) {
+	tlsInfo := &e.cfg.ClientTLSInfo
+	switch murl.Scheme {
+	case "http":
+		tlsInfo = nil
+	case "https", "unixs":
+		if e.cfg.ClientTLSInfo.Empty() {
+			return nil, ErrMissingClientTLSInfoForMetricsURL
+		}
+	}
+	return transport.NewListenerWithOpts(murl.Host, murl.Scheme,
+		transport.WithTLSInfo(tlsInfo),
+		transport.WithSocketOpts(&e.cfg.SocketOpts),
+	)
+}
+
+func (e *Etcd) serveMetrics() (err error) {
+	if len(e.cfg.ListenMetricsUrls) > 0 {
+		metricsMux := http.NewServeMux()
+		etcdhttp.HandleMetrics(metricsMux)
+		etcdhttp.HandleHealth(e.cfg.logger, metricsMux, e.Server)
+
+		for _, murl := range e.cfg.ListenMetricsUrls {
+			u := murl
+			ml, err := e.createMetricsListener(murl)
+			if err != nil {
+				return err
+			}
+			e.metricsListeners = append(e.metricsListeners, ml)
+
+			e.startHandler(func() error {
+				e.cfg.logger.Info(
+					"serving metrics",
+					zap.String("address", u.String()),
+				)
+				return http.Serve(ml, metricsMux)
+			})
+		}
+	}
+	return nil
+}
+
+func (e *Etcd) startHandler(handler func() error) {
+	// start each handler in a separate goroutine
+	e.wg.Add(1)
+	go func() {
+		defer e.wg.Done()
+		e.errHandler(handler())
+	}()
+}
+
+func (e *Etcd) errHandler(err error) {
+	if err != nil {
+		e.GetLogger().Error("setting up serving from embedded etcd failed.", zap.Error(err))
+	}
+	select {
+	case <-e.stopc:
+		return
+	default:
+	}
+	select {
+	case <-e.stopc:
+	case e.errc <- err:
+	}
+}
+
+// GetLogger returns the logger.
+func (e *Etcd) GetLogger() *zap.Logger {
+	e.cfg.loggerMu.RLock()
+	l := e.cfg.logger
+	e.cfg.loggerMu.RUnlock()
+	return l
+}
+
+func parseCompactionRetention(mode, retention string) (ret time.Duration, err error) {
+	h, err := strconv.Atoi(retention)
+	if err == nil && h >= 0 {
+		switch mode {
+		case CompactorModeRevision:
+			ret = time.Duration(int64(h))
+		case CompactorModePeriodic:
+			ret = time.Duration(int64(h)) * time.Hour
+		case "":
+			return 0, errors.New("--auto-compaction-mode is undefined")
+		}
+	} else {
+		// periodic compaction
+		ret, err = time.ParseDuration(retention)
+		if err != nil {
+			return 0, fmt.Errorf("error parsing CompactionRetention: %w", err)
+		}
+	}
+	return ret, nil
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/embed/serve.go b/vendor/go.etcd.io/etcd/server/v3/embed/serve.go
new file mode 100644
index 0000000..e50529d
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/embed/serve.go
@@ -0,0 +1,558 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package embed
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	defaultLog "log"
+	"net"
+	"net/http"
+	"strings"
+	"sync"
+
+	gw "github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
+	"github.com/soheilhy/cmux"
+	"github.com/tmc/grpc-websocket-proxy/wsproxy"
+	"go.uber.org/zap"
+	"golang.org/x/net/http2"
+	"golang.org/x/net/trace"
+	"google.golang.org/grpc"
+	"google.golang.org/protobuf/encoding/protojson"
+
+	etcdservergw "go.etcd.io/etcd/api/v3/etcdserverpb/gw"
+	"go.etcd.io/etcd/client/pkg/v3/transport"
+	"go.etcd.io/etcd/pkg/v3/debugutil"
+	"go.etcd.io/etcd/pkg/v3/httputil"
+	"go.etcd.io/etcd/server/v3/config"
+	"go.etcd.io/etcd/server/v3/etcdserver"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v3client"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v3election"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v3election/v3electionpb"
+	v3electiongw "go.etcd.io/etcd/server/v3/etcdserver/api/v3election/v3electionpb/gw"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v3lock"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v3lock/v3lockpb"
+	v3lockgw "go.etcd.io/etcd/server/v3/etcdserver/api/v3lock/v3lockpb/gw"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc"
+)
+
+type serveCtx struct {
+	lg *zap.Logger
+	l  net.Listener
+
+	scheme   string
+	addr     string
+	network  string
+	secure   bool
+	insecure bool
+	httpOnly bool
+
+	// ctx is used to control the grpc gateway. Terminate the grpc gateway
+	// by calling `cancel` when shutting down the etcd.
+	ctx    context.Context
+	cancel context.CancelFunc
+
+	userHandlers    map[string]http.Handler
+	serviceRegister func(*grpc.Server)
+
+	// serversC is used to receive the http and grpc server objects (created
+	// in `serve`), both of which will be closed when shutting down the etcd.
+	// Close it when `serve` returns or when etcd fails to bootstrap.
+	serversC chan *servers
+	// closeOnce is to ensure `serversC` is closed only once.
+	closeOnce sync.Once
+
+	// wg is used to track the lifecycle of all sub goroutines created by `serve`.
+	wg sync.WaitGroup
+}
+
+func (sctx *serveCtx) startHandler(errHandler func(error), handler func() error) {
+	// start each handler in a separate goroutine
+	sctx.wg.Add(1)
+	go func() {
+		defer sctx.wg.Done()
+		err := handler()
+		if errHandler != nil {
+			errHandler(err)
+		}
+	}()
+}
+
+type servers struct {
+	secure bool
+	grpc   *grpc.Server
+	http   *http.Server
+}
+
+func newServeCtx(lg *zap.Logger) *serveCtx {
+	ctx, cancel := context.WithCancel(context.Background())
+	if lg == nil {
+		lg = zap.NewNop()
+	}
+	return &serveCtx{
+		lg:           lg,
+		ctx:          ctx,
+		cancel:       cancel,
+		userHandlers: make(map[string]http.Handler),
+		serversC:     make(chan *servers, 2), // in case sctx.insecure,sctx.secure true
+	}
+}
+
+// serve accepts incoming connections on the listener l,
+// creating a new service goroutine for each. The service goroutines
+// read requests and then call handler to reply to them.
+func (sctx *serveCtx) serve(
+	s *etcdserver.EtcdServer,
+	tlsinfo *transport.TLSInfo,
+	handler http.Handler,
+	errHandler func(error),
+	grpcDialForRestGatewayBackends func(ctx context.Context) (*grpc.ClientConn, error),
+	splitHTTP bool,
+	gopts ...grpc.ServerOption,
+) (err error) {
+	logger := defaultLog.New(io.Discard, "etcdhttp", 0)
+
+	// Make sure serversC is closed even if we prematurely exit the function.
+	defer sctx.close()
+
+	select {
+	case <-s.StoppingNotify():
+		return errors.New("server is stopping")
+	case <-s.ReadyNotify():
+	}
+
+	sctx.lg.Info("ready to serve client requests")
+
+	m := cmux.New(sctx.l)
+	var server func() error
+	onlyGRPC := splitHTTP && !sctx.httpOnly
+	onlyHTTP := splitHTTP && sctx.httpOnly
+	grpcEnabled := !onlyHTTP
+	httpEnabled := !onlyGRPC
+
+	v3c := v3client.New(s)
+	servElection := v3election.NewElectionServer(v3c)
+	servLock := v3lock.NewLockServer(v3c)
+
+	var gwmux *gw.ServeMux
+	if s.Cfg.EnableGRPCGateway {
+		// GRPC gateway connects to grpc server via connection provided by grpc dial.
+		gwmux, err = sctx.registerGateway(grpcDialForRestGatewayBackends)
+		if err != nil {
+			sctx.lg.Error("registerGateway failed", zap.Error(err))
+			return err
+		}
+	}
+	var traffic string
+	switch {
+	case onlyGRPC:
+		traffic = "grpc"
+	case onlyHTTP:
+		traffic = "http"
+	default:
+		traffic = "grpc+http"
+	}
+
+	if sctx.insecure {
+		var gs *grpc.Server
+		var srv *http.Server
+		if httpEnabled {
+			httpmux := sctx.createMux(gwmux, handler)
+			srv = &http.Server{
+				Handler:  createAccessController(sctx.lg, s, httpmux),
+				ErrorLog: logger, // do not log user error
+			}
+			if err = configureHTTPServer(srv, s.Cfg); err != nil {
+				sctx.lg.Error("Configure http server failed", zap.Error(err))
+				return err
+			}
+		}
+		if grpcEnabled {
+			gs = v3rpc.Server(s, nil, nil, gopts...)
+			v3electionpb.RegisterElectionServer(gs, servElection)
+			v3lockpb.RegisterLockServer(gs, servLock)
+			if sctx.serviceRegister != nil {
+				sctx.serviceRegister(gs)
+			}
+			defer func(gs *grpc.Server) {
+				if err != nil {
+					sctx.lg.Warn("stopping insecure grpc server due to error", zap.Error(err))
+					gs.Stop()
+					sctx.lg.Warn("stopped insecure grpc server due to error", zap.Error(err))
+				}
+			}(gs)
+		}
+		if onlyGRPC {
+			server = func() error {
+				return gs.Serve(sctx.l)
+			}
+		} else {
+			server = m.Serve
+
+			httpl := m.Match(cmux.HTTP1())
+			sctx.startHandler(errHandler, func() error {
+				return srv.Serve(httpl)
+			})
+
+			if grpcEnabled {
+				grpcl := m.Match(cmux.HTTP2())
+				sctx.startHandler(errHandler, func() error {
+					return gs.Serve(grpcl)
+				})
+			}
+		}
+
+		sctx.serversC <- &servers{grpc: gs, http: srv}
+		sctx.lg.Info(
+			"serving client traffic insecurely; this is strongly discouraged!",
+			zap.String("traffic", traffic),
+			zap.String("address", sctx.l.Addr().String()),
+		)
+	}
+
+	if sctx.secure {
+		var gs *grpc.Server
+		var srv *http.Server
+
+		tlscfg, tlsErr := tlsinfo.ServerConfig()
+		if tlsErr != nil {
+			return tlsErr
+		}
+
+		if grpcEnabled {
+			gs = v3rpc.Server(s, tlscfg, nil, gopts...)
+			v3electionpb.RegisterElectionServer(gs, servElection)
+			v3lockpb.RegisterLockServer(gs, servLock)
+			if sctx.serviceRegister != nil {
+				sctx.serviceRegister(gs)
+			}
+			defer func(gs *grpc.Server) {
+				if err != nil {
+					sctx.lg.Warn("stopping secure grpc server due to error", zap.Error(err))
+					gs.Stop()
+					sctx.lg.Warn("stopped secure grpc server due to error", zap.Error(err))
+				}
+			}(gs)
+		}
+		if httpEnabled {
+			if grpcEnabled {
+				handler = grpcHandlerFunc(gs, handler)
+			}
+			httpmux := sctx.createMux(gwmux, handler)
+
+			srv = &http.Server{
+				Handler:   createAccessController(sctx.lg, s, httpmux),
+				TLSConfig: tlscfg,
+				ErrorLog:  logger, // do not log user error
+			}
+			if err = configureHTTPServer(srv, s.Cfg); err != nil {
+				sctx.lg.Error("Configure https server failed", zap.Error(err))
+				return err
+			}
+		}
+
+		if onlyGRPC {
+			server = func() error { return gs.Serve(sctx.l) }
+		} else {
+			server = m.Serve
+
+			tlsl, tlsErr := transport.NewTLSListener(m.Match(cmux.Any()), tlsinfo)
+			if tlsErr != nil {
+				return tlsErr
+			}
+			sctx.startHandler(errHandler, func() error {
+				return srv.Serve(tlsl)
+			})
+		}
+
+		sctx.serversC <- &servers{secure: true, grpc: gs, http: srv}
+		sctx.lg.Info(
+			"serving client traffic securely",
+			zap.String("traffic", traffic),
+			zap.String("address", sctx.l.Addr().String()),
+		)
+	}
+
+	err = server()
+	sctx.close()
+	sctx.wg.Wait()
+	return err
+}
+
+func configureHTTPServer(srv *http.Server, cfg config.ServerConfig) error {
+	// todo (ahrtr): should we support configuring other parameters in the future as well?
+	return http2.ConfigureServer(srv, &http2.Server{
+		MaxConcurrentStreams: cfg.MaxConcurrentStreams,
+	})
+}
+
+// grpcHandlerFunc returns an http.Handler that delegates to grpcServer on incoming gRPC
+// connections or otherHandler otherwise. Given in gRPC docs.
+func grpcHandlerFunc(grpcServer *grpc.Server, otherHandler http.Handler) http.Handler {
+	if otherHandler == nil {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			grpcServer.ServeHTTP(w, r)
+		})
+	}
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.ProtoMajor == 2 && strings.Contains(r.Header.Get("Content-Type"), "application/grpc") {
+			grpcServer.ServeHTTP(w, r)
+		} else {
+			otherHandler.ServeHTTP(w, r)
+		}
+	})
+}
+
+type registerHandlerFunc func(context.Context, *gw.ServeMux, *grpc.ClientConn) error
+
+func (sctx *serveCtx) registerGateway(dial func(ctx context.Context) (*grpc.ClientConn, error)) (*gw.ServeMux, error) {
+	ctx := sctx.ctx
+
+	conn, err := dial(ctx)
+	if err != nil {
+		return nil, err
+	}
+
+	// Refer to https://grpc-ecosystem.github.io/grpc-gateway/docs/mapping/customizing_your_gateway/
+	gwmux := gw.NewServeMux(
+		gw.WithMarshalerOption(gw.MIMEWildcard,
+			&gw.HTTPBodyMarshaler{
+				Marshaler: &gw.JSONPb{
+					MarshalOptions: protojson.MarshalOptions{
+						UseProtoNames:   true,
+						EmitUnpopulated: false,
+					},
+					UnmarshalOptions: protojson.UnmarshalOptions{
+						DiscardUnknown: true,
+					},
+				},
+			},
+		),
+	)
+
+	handlers := []registerHandlerFunc{
+		etcdservergw.RegisterKVHandler,
+		etcdservergw.RegisterWatchHandler,
+		etcdservergw.RegisterLeaseHandler,
+		etcdservergw.RegisterClusterHandler,
+		etcdservergw.RegisterMaintenanceHandler,
+		etcdservergw.RegisterAuthHandler,
+		v3lockgw.RegisterLockHandler,
+		v3electiongw.RegisterElectionHandler,
+	}
+	for _, h := range handlers {
+		if err := h(ctx, gwmux, conn); err != nil {
+			return nil, err
+		}
+	}
+	sctx.startHandler(nil, func() error {
+		<-ctx.Done()
+		if cerr := conn.Close(); cerr != nil {
+			sctx.lg.Warn(
+				"failed to close connection",
+				zap.String("address", sctx.l.Addr().String()),
+				zap.Error(cerr),
+			)
+		}
+		return nil
+	})
+
+	return gwmux, nil
+}
+
+type wsProxyZapLogger struct {
+	*zap.Logger
+}
+
+func (w wsProxyZapLogger) Warnln(i ...any) {
+	w.Warn(fmt.Sprint(i...))
+}
+
+func (w wsProxyZapLogger) Debugln(i ...any) {
+	w.Debug(fmt.Sprint(i...))
+}
+
+func (sctx *serveCtx) createMux(gwmux *gw.ServeMux, handler http.Handler) *http.ServeMux {
+	httpmux := http.NewServeMux()
+	for path, h := range sctx.userHandlers {
+		httpmux.Handle(path, h)
+	}
+
+	if gwmux != nil {
+		httpmux.Handle(
+			"/v3/",
+			wsproxy.WebsocketProxy(
+				gwmux,
+				wsproxy.WithRequestMutator(
+					// Default to the POST method for streams
+					func(_ *http.Request, outgoing *http.Request) *http.Request {
+						outgoing.Method = "POST"
+						return outgoing
+					},
+				),
+				wsproxy.WithMaxRespBodyBufferSize(0x7fffffff),
+				wsproxy.WithLogger(wsProxyZapLogger{sctx.lg}),
+			),
+		)
+	}
+	if handler != nil {
+		httpmux.Handle("/", handler)
+	}
+	return httpmux
+}
+
+// createAccessController wraps HTTP multiplexer:
+// - mutate gRPC gateway request paths
+// - check hostname whitelist
+// client HTTP requests goes here first
+func createAccessController(lg *zap.Logger, s *etcdserver.EtcdServer, mux *http.ServeMux) http.Handler {
+	if lg == nil {
+		lg = zap.NewNop()
+	}
+	return &accessController{lg: lg, s: s, mux: mux}
+}
+
+type accessController struct {
+	lg  *zap.Logger
+	s   *etcdserver.EtcdServer
+	mux *http.ServeMux
+}
+
+func (ac *accessController) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
+	if req == nil {
+		http.Error(rw, "Request is nil", http.StatusBadRequest)
+		return
+	}
+	// redirect for backward compatibilities
+	if req.URL != nil && strings.HasPrefix(req.URL.Path, "/v3beta/") {
+		req.URL.Path = strings.Replace(req.URL.Path, "/v3beta/", "/v3/", 1)
+	}
+
+	if req.TLS == nil { // check origin if client connection is not secure
+		host := httputil.GetHostname(req)
+		if !ac.s.AccessController.IsHostWhitelisted(host) {
+			ac.lg.Warn(
+				"rejecting HTTP request to prevent DNS rebinding attacks",
+				zap.String("host", host),
+			)
+			http.Error(rw, errCVE20185702(host), http.StatusMisdirectedRequest)
+			return
+		}
+	} else if ac.s.Cfg.ClientCertAuthEnabled && ac.s.Cfg.EnableGRPCGateway &&
+		ac.s.AuthStore().IsAuthEnabled() && strings.HasPrefix(req.URL.Path, "/v3/") {
+		for _, chains := range req.TLS.VerifiedChains {
+			if len(chains) < 1 {
+				continue
+			}
+			if len(chains[0].Subject.CommonName) != 0 {
+				http.Error(rw, "CommonName of client sending a request against gateway will be ignored and not used as expected", http.StatusBadRequest)
+				return
+			}
+		}
+	}
+
+	// Write CORS header.
+	if ac.s.AccessController.OriginAllowed("*") {
+		addCORSHeader(rw, "*")
+	} else if origin := req.Header.Get("Origin"); ac.s.OriginAllowed(origin) {
+		addCORSHeader(rw, origin)
+	}
+
+	if req.Method == http.MethodOptions {
+		rw.WriteHeader(http.StatusOK)
+		return
+	}
+
+	ac.mux.ServeHTTP(rw, req)
+}
+
+// addCORSHeader adds the correct cors headers given an origin
+func addCORSHeader(w http.ResponseWriter, origin string) {
+	w.Header().Add("Access-Control-Allow-Methods", "POST, GET, OPTIONS, PUT, DELETE")
+	w.Header().Add("Access-Control-Allow-Origin", origin)
+	w.Header().Add("Access-Control-Allow-Headers", "accept, content-type, authorization")
+}
+
+// https://github.com/transmission/transmission/pull/468
+func errCVE20185702(host string) string {
+	return fmt.Sprintf(`
+etcd received your request, but the Host header was unrecognized.
+
+To fix this, choose one of the following options:
+- Enable TLS, then any HTTPS request will be allowed.
+- Add the hostname you want to use to the whitelist in settings.
+  - e.g. etcd --host-whitelist %q
+
+This requirement has been added to help prevent "DNS Rebinding" attacks (CVE-2018-5702).
+`, host)
+}
+
+// WrapCORS wraps existing handler with CORS.
+// TODO: deprecate this after v2 proxy deprecate
+func WrapCORS(cors map[string]struct{}, h http.Handler) http.Handler {
+	return &corsHandler{
+		ac: &etcdserver.AccessController{CORS: cors},
+		h:  h,
+	}
+}
+
+type corsHandler struct {
+	ac *etcdserver.AccessController
+	h  http.Handler
+}
+
+func (ch *corsHandler) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
+	if ch.ac.OriginAllowed("*") {
+		addCORSHeader(rw, "*")
+	} else if origin := req.Header.Get("Origin"); ch.ac.OriginAllowed(origin) {
+		addCORSHeader(rw, origin)
+	}
+
+	if req.Method == http.MethodOptions {
+		rw.WriteHeader(http.StatusOK)
+		return
+	}
+
+	ch.h.ServeHTTP(rw, req)
+}
+
+func (sctx *serveCtx) registerUserHandler(s string, h http.Handler) {
+	if sctx.userHandlers[s] != nil {
+		sctx.lg.Warn("path is already registered by user handler", zap.String("path", s))
+		return
+	}
+	sctx.userHandlers[s] = h
+}
+
+func (sctx *serveCtx) registerPprof() {
+	for p, h := range debugutil.PProfHandlers() {
+		sctx.registerUserHandler(p, h)
+	}
+}
+
+func (sctx *serveCtx) registerTrace() {
+	reqf := func(w http.ResponseWriter, r *http.Request) { trace.Render(w, r, true) }
+	sctx.registerUserHandler("/debug/requests", http.HandlerFunc(reqf))
+	evf := func(w http.ResponseWriter, r *http.Request) { trace.RenderEvents(w, r, true) }
+	sctx.registerUserHandler("/debug/events", http.HandlerFunc(evf))
+}
+
+func (sctx *serveCtx) close() {
+	sctx.closeOnce.Do(func() {
+		close(sctx.serversC)
+	})
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/embed/util.go b/vendor/go.etcd.io/etcd/server/v3/embed/util.go
new file mode 100644
index 0000000..32efbe6
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/embed/util.go
@@ -0,0 +1,29 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package embed
+
+import (
+	"path/filepath"
+
+	"go.etcd.io/etcd/server/v3/storage/wal"
+)
+
+func isMemberInitialized(cfg *Config) bool {
+	walDir := cfg.WalDir
+	if walDir == "" {
+		walDir = filepath.Join(cfg.Dir, "member", "wal")
+	}
+	return wal.Exist(walDir)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/adapters.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/adapters.go
new file mode 100644
index 0000000..bc9790b
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/adapters.go
@@ -0,0 +1,89 @@
+// Copyright 2021 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package etcdserver
+
+import (
+	"context"
+
+	"github.com/coreos/go-semver/semver"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/api/v3/membershippb"
+	"go.etcd.io/etcd/api/v3/version"
+	serverversion "go.etcd.io/etcd/server/v3/etcdserver/version"
+	"go.etcd.io/etcd/server/v3/storage/schema"
+)
+
+// serverVersionAdapter implements the interface Server defined in package
+// go.etcd.io/etcd/server/v3/etcdserver/version, and it's needed by Monitor
+// in the same package.
+type serverVersionAdapter struct {
+	*EtcdServer
+}
+
+func NewServerVersionAdapter(s *EtcdServer) serverversion.Server {
+	return &serverVersionAdapter{
+		EtcdServer: s,
+	}
+}
+
+var _ serverversion.Server = (*serverVersionAdapter)(nil)
+
+func (s *serverVersionAdapter) UpdateClusterVersion(version string) {
+	s.GoAttach(func() { s.updateClusterVersionV3(version) })
+}
+
+func (s *serverVersionAdapter) LinearizableReadNotify(ctx context.Context) error {
+	return s.linearizableReadNotify(ctx)
+}
+
+func (s *serverVersionAdapter) DowngradeEnable(ctx context.Context, targetVersion *semver.Version) error {
+	raftRequest := membershippb.DowngradeInfoSetRequest{Enabled: true, Ver: targetVersion.String()}
+	_, err := s.raftRequest(ctx, pb.InternalRaftRequest{DowngradeInfoSet: &raftRequest})
+	return err
+}
+
+func (s *serverVersionAdapter) DowngradeCancel(ctx context.Context) error {
+	raftRequest := membershippb.DowngradeInfoSetRequest{Enabled: false}
+	_, err := s.raftRequest(ctx, pb.InternalRaftRequest{DowngradeInfoSet: &raftRequest})
+	return err
+}
+
+func (s *serverVersionAdapter) GetClusterVersion() *semver.Version {
+	return s.cluster.Version()
+}
+
+func (s *serverVersionAdapter) GetDowngradeInfo() *serverversion.DowngradeInfo {
+	return s.cluster.DowngradeInfo()
+}
+
+func (s *serverVersionAdapter) GetMembersVersions() map[string]*version.Versions {
+	return getMembersVersions(s.lg, s.cluster, s.MemberID(), s.peerRt, s.Cfg.ReqTimeout())
+}
+
+func (s *serverVersionAdapter) GetStorageVersion() *semver.Version {
+	return s.StorageVersion()
+}
+
+func (s *serverVersionAdapter) UpdateStorageVersion(target semver.Version) error {
+	// `applySnapshot` sets a new backend instance, so we need to acquire the bemu lock.
+	s.bemu.RLock()
+	defer s.bemu.RUnlock()
+
+	tx := s.be.BatchTx()
+	tx.LockOutsideApply()
+	defer tx.Unlock()
+	return schema.UnsafeMigrate(s.lg, tx, s.r.storage, target)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/capability.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/capability.go
new file mode 100644
index 0000000..cf535ec
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/capability.go
@@ -0,0 +1,96 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package api
+
+import (
+	"sync"
+
+	"github.com/coreos/go-semver/semver"
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/api/v3/version"
+	serverversion "go.etcd.io/etcd/server/v3/etcdserver/version"
+)
+
+type Capability string
+
+const (
+	AuthCapability  Capability = "auth"
+	V3rpcCapability Capability = "v3rpc"
+)
+
+var (
+	// capabilityMaps is a static map of version to capability map.
+	capabilityMaps = map[string]map[Capability]bool{
+		"3.0.0": {AuthCapability: true, V3rpcCapability: true},
+		"3.1.0": {AuthCapability: true, V3rpcCapability: true},
+		"3.2.0": {AuthCapability: true, V3rpcCapability: true},
+		"3.3.0": {AuthCapability: true, V3rpcCapability: true},
+		"3.4.0": {AuthCapability: true, V3rpcCapability: true},
+		"3.5.0": {AuthCapability: true, V3rpcCapability: true},
+		"3.6.0": {AuthCapability: true, V3rpcCapability: true},
+	}
+
+	enableMapMu sync.RWMutex
+	// enabledMap points to a map in capabilityMaps
+	enabledMap map[Capability]bool
+
+	curVersion *semver.Version
+)
+
+func init() {
+	enabledMap = map[Capability]bool{
+		AuthCapability:  true,
+		V3rpcCapability: true,
+	}
+}
+
+// UpdateCapability updates the enabledMap when the cluster version increases.
+func UpdateCapability(lg *zap.Logger, v *semver.Version) {
+	if v == nil {
+		// if recovered but version was never set by cluster
+		return
+	}
+	enableMapMu.Lock()
+	if curVersion != nil && !serverversion.IsValidClusterVersionChange(curVersion, v) {
+		enableMapMu.Unlock()
+		return
+	}
+	curVersion = v
+	enabledMap = capabilityMaps[curVersion.String()]
+	enableMapMu.Unlock()
+
+	if lg != nil {
+		lg.Info(
+			"enabled capabilities for version",
+			zap.String("cluster-version", version.Cluster(v.String())),
+		)
+	}
+}
+
+func IsCapabilityEnabled(c Capability) bool {
+	enableMapMu.RLock()
+	defer enableMapMu.RUnlock()
+	if enabledMap == nil {
+		return false
+	}
+	return enabledMap[c]
+}
+
+func EnableCapability(c Capability) {
+	enableMapMu.Lock()
+	defer enableMapMu.Unlock()
+	enabledMap[c] = true
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/cluster.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/cluster.go
new file mode 100644
index 0000000..f05997d
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/cluster.go
@@ -0,0 +1,38 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package api
+
+import (
+	"go.etcd.io/etcd/client/pkg/v3/types"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/membership"
+
+	"github.com/coreos/go-semver/semver"
+)
+
+// Cluster is an interface representing a collection of members in one etcd cluster.
+type Cluster interface {
+	// ID returns the cluster ID
+	ID() types.ID
+	// ClientURLs returns an aggregate set of all URLs on which this
+	// cluster is listening for client requests
+	ClientURLs() []string
+	// Members returns a slice of members sorted by their ID
+	Members() []*membership.Member
+	// Member retrieves a particular member based on ID, or nil if the
+	// member does not exist in the cluster
+	Member(id types.ID) *membership.Member
+	// Version is the cluster-wide minimum major.minor version.
+	Version() *semver.Version
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/doc.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/doc.go
new file mode 100644
index 0000000..f44881b
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/doc.go
@@ -0,0 +1,16 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package api manages the capabilities and features that are exposed to clients by the etcd cluster.
+package api
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/etcdhttp/debug.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/etcdhttp/debug.go
new file mode 100644
index 0000000..ab7feee
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/etcdhttp/debug.go
@@ -0,0 +1,47 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package etcdhttp
+
+import (
+	"expvar"
+	"fmt"
+	"net/http"
+)
+
+const (
+	varsPath = "/debug/vars"
+)
+
+func HandleDebug(mux *http.ServeMux) {
+	mux.HandleFunc(varsPath, serveVars)
+}
+
+func serveVars(w http.ResponseWriter, r *http.Request) {
+	if !allowMethod(w, r, "GET") {
+		return
+	}
+
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
+	fmt.Fprint(w, "{\n")
+	first := true
+	expvar.Do(func(kv expvar.KeyValue) {
+		if !first {
+			fmt.Fprint(w, ",\n")
+		}
+		first = false
+		fmt.Fprintf(w, "%q: %s", kv.Key, kv.Value)
+	})
+	fmt.Fprint(w, "\n}\n")
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/etcdhttp/doc.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/etcdhttp/doc.go
new file mode 100644
index 0000000..a03b626
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/etcdhttp/doc.go
@@ -0,0 +1,16 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package etcdhttp implements HTTP transportation layer for etcdserver.
+package etcdhttp
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/etcdhttp/health.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/etcdhttp/health.go
new file mode 100644
index 0000000..26ed4ca
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/etcdhttp/health.go
@@ -0,0 +1,447 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// This file defines the http endpoints for etcd health checks.
+// The endpoints include /livez, /readyz and /health.
+
+package etcdhttp
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"path"
+	"strings"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"go.uber.org/zap"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/client/pkg/v3/types"
+	"go.etcd.io/etcd/server/v3/auth"
+	"go.etcd.io/etcd/server/v3/config"
+	"go.etcd.io/raft/v3"
+)
+
+const (
+	PathHealth                 = "/health"
+	PathProxyHealth            = "/proxy/health"
+	HealthStatusSuccess string = "success"
+	HealthStatusError   string = "error"
+	checkTypeLivez             = "livez"
+	checkTypeReadyz            = "readyz"
+	checkTypeHealth            = "health"
+)
+
+type ServerHealth interface {
+	Alarms() []*pb.AlarmMember
+	Leader() types.ID
+	Range(context.Context, *pb.RangeRequest) (*pb.RangeResponse, error)
+	Config() config.ServerConfig
+	AuthStore() auth.AuthStore
+	IsLearner() bool
+}
+
+// HandleHealth registers metrics and health handlers. it checks health by using v3 range request
+// and its corresponding timeout.
+func HandleHealth(lg *zap.Logger, mux *http.ServeMux, srv ServerHealth) {
+	mux.Handle(PathHealth, NewHealthHandler(lg, func(ctx context.Context, excludedAlarms StringSet, serializable bool) Health {
+		if h := checkAlarms(lg, srv, excludedAlarms); h.Health != "true" {
+			return h
+		}
+		if h := checkLeader(lg, srv, serializable); h.Health != "true" {
+			return h
+		}
+		return checkAPI(ctx, lg, srv, serializable)
+	}))
+
+	installLivezEndpoints(lg, mux, srv)
+	installReadyzEndpoints(lg, mux, srv)
+}
+
+// NewHealthHandler handles '/health' requests.
+func NewHealthHandler(lg *zap.Logger, hfunc func(ctx context.Context, excludedAlarms StringSet, Serializable bool) Health) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != http.MethodGet {
+			w.Header().Set("Allow", http.MethodGet)
+			http.Error(w, "Method Not Allowed", http.StatusMethodNotAllowed)
+			lg.Warn("/health error", zap.Int("status-code", http.StatusMethodNotAllowed))
+			return
+		}
+		excludedAlarms := getQuerySet(r, "exclude")
+		// Passing the query parameter "serializable=true" ensures that the
+		// health of the local etcd is checked vs the health of the cluster.
+		// This is useful for probes attempting to validate the liveness of
+		// the etcd process vs readiness of the cluster to serve requests.
+		serializableFlag := getSerializableFlag(r)
+		h := hfunc(r.Context(), excludedAlarms, serializableFlag)
+		defer func() {
+			if h.Health == "true" {
+				healthSuccess.Inc()
+			} else {
+				healthFailed.Inc()
+			}
+		}()
+		d, _ := json.Marshal(h)
+		if h.Health != "true" {
+			http.Error(w, string(d), http.StatusServiceUnavailable)
+			lg.Warn("/health error", zap.String("output", string(d)), zap.Int("status-code", http.StatusServiceUnavailable))
+			return
+		}
+		w.WriteHeader(http.StatusOK)
+		w.Write(d)
+		lg.Debug("/health OK", zap.Int("status-code", http.StatusOK))
+	}
+}
+
+var (
+	healthSuccess = prometheus.NewCounter(prometheus.CounterOpts{
+		Namespace: "etcd",
+		Subsystem: "server",
+		Name:      "health_success",
+		Help:      "The total number of successful health checks",
+	})
+	healthFailed = prometheus.NewCounter(prometheus.CounterOpts{
+		Namespace: "etcd",
+		Subsystem: "server",
+		Name:      "health_failures",
+		Help:      "The total number of failed health checks",
+	})
+	healthCheckGauge = prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Namespace: "etcd",
+			Subsystem: "server",
+			Name:      "healthcheck",
+			Help:      "The result of each kind of healthcheck.",
+		},
+		[]string{"type", "name"},
+	)
+	healthCheckCounter = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: "etcd",
+			Subsystem: "server",
+			Name:      "healthchecks_total",
+			Help:      "The total number of each kind of healthcheck.",
+		},
+		[]string{"type", "name", "status"},
+	)
+)
+
+func init() {
+	prometheus.MustRegister(healthSuccess)
+	prometheus.MustRegister(healthFailed)
+	prometheus.MustRegister(healthCheckGauge)
+	prometheus.MustRegister(healthCheckCounter)
+}
+
+// Health defines etcd server health status.
+// TODO: remove manual parsing in etcdctl cluster-health
+type Health struct {
+	Health string `json:"health"`
+	Reason string `json:"reason"`
+}
+
+// HealthStatus is used in new /readyz or /livez health checks instead of the Health struct.
+type HealthStatus struct {
+	Reason string `json:"reason"`
+	Status string `json:"status"`
+}
+
+func getQuerySet(r *http.Request, query string) StringSet {
+	querySet := make(map[string]struct{})
+	qs, found := r.URL.Query()[query]
+	if found {
+		for _, q := range qs {
+			if len(q) == 0 {
+				continue
+			}
+			querySet[q] = struct{}{}
+		}
+	}
+	return querySet
+}
+
+func getSerializableFlag(r *http.Request) bool {
+	return r.URL.Query().Get("serializable") == "true"
+}
+
+// TODO: etcdserver.ErrNoLeader in health API
+
+func checkAlarms(lg *zap.Logger, srv ServerHealth, excludedAlarms StringSet) Health {
+	h := Health{Health: "true"}
+
+	for _, v := range srv.Alarms() {
+		alarmName := v.Alarm.String()
+		if _, found := excludedAlarms[alarmName]; found {
+			lg.Debug("/health excluded alarm", zap.String("alarm", v.String()))
+			continue
+		}
+
+		h.Health = "false"
+		switch v.Alarm {
+		case pb.AlarmType_NOSPACE:
+			h.Reason = "ALARM NOSPACE"
+		case pb.AlarmType_CORRUPT:
+			h.Reason = "ALARM CORRUPT"
+		default:
+			h.Reason = "ALARM UNKNOWN"
+		}
+		lg.Warn("serving /health false due to an alarm", zap.String("alarm", v.String()))
+		return h
+	}
+
+	return h
+}
+
+func checkLeader(lg *zap.Logger, srv ServerHealth, serializable bool) Health {
+	h := Health{Health: "true"}
+	if !serializable && (uint64(srv.Leader()) == raft.None) {
+		h.Health = "false"
+		h.Reason = "RAFT NO LEADER"
+		lg.Warn("serving /health false; no leader")
+	}
+	return h
+}
+
+func checkAPI(ctx context.Context, lg *zap.Logger, srv ServerHealth, serializable bool) Health {
+	h := Health{Health: "true"}
+	cfg := srv.Config()
+	ctx = srv.AuthStore().WithRoot(ctx)
+	cctx, cancel := context.WithTimeout(ctx, cfg.ReqTimeout())
+	_, err := srv.Range(cctx, &pb.RangeRequest{KeysOnly: true, Limit: 1, Serializable: serializable})
+	cancel()
+	if err != nil {
+		h.Health = "false"
+		h.Reason = fmt.Sprintf("RANGE ERROR:%s", err)
+		lg.Warn("serving /health false; Range fails", zap.Error(err))
+		return h
+	}
+	lg.Debug("serving /health true")
+	return h
+}
+
+type HealthCheck func(ctx context.Context) error
+
+type CheckRegistry struct {
+	checkType string
+	checks    map[string]HealthCheck
+}
+
+func installLivezEndpoints(lg *zap.Logger, mux *http.ServeMux, server ServerHealth) {
+	reg := CheckRegistry{checkType: checkTypeLivez, checks: make(map[string]HealthCheck)}
+	reg.Register("serializable_read", readCheck(server, true /* serializable */))
+	reg.InstallHTTPEndpoints(lg, mux)
+}
+
+func installReadyzEndpoints(lg *zap.Logger, mux *http.ServeMux, server ServerHealth) {
+	reg := CheckRegistry{checkType: checkTypeReadyz, checks: make(map[string]HealthCheck)}
+	reg.Register("data_corruption", activeAlarmCheck(server, pb.AlarmType_CORRUPT))
+	// serializable_read checks if local read is ok.
+	// linearizable_read checks if there is consensus in the cluster.
+	// Having both serializable_read and linearizable_read helps isolate the cause of problems if there is a read failure.
+	reg.Register("serializable_read", readCheck(server, true))
+	// linearizable_read check would be replaced by read_index check in 3.6
+	reg.Register("linearizable_read", readCheck(server, false))
+	// check if local is learner
+	reg.Register("non_learner", learnerCheck(server))
+	reg.InstallHTTPEndpoints(lg, mux)
+}
+
+func (reg *CheckRegistry) Register(name string, check HealthCheck) {
+	reg.checks[name] = check
+}
+
+func (reg *CheckRegistry) RootPath() string {
+	return "/" + reg.checkType
+}
+
+// InstallHttpEndpoints installs the http handlers for the health checks.
+//
+// Deprecated: Please use (*CheckRegistry) InstallHTTPEndpoints instead.
+//
+//revive:disable-next-line:var-naming
+func (reg *CheckRegistry) InstallHttpEndpoints(lg *zap.Logger, mux *http.ServeMux) {
+	reg.InstallHTTPEndpoints(lg, mux)
+}
+
+func (reg *CheckRegistry) InstallHTTPEndpoints(lg *zap.Logger, mux *http.ServeMux) {
+	checkNames := make([]string, 0, len(reg.checks))
+	for k := range reg.checks {
+		checkNames = append(checkNames, k)
+	}
+
+	// installs the http handler for the root path.
+	reg.installRootHTTPEndpoint(lg, mux, checkNames...)
+	for _, checkName := range checkNames {
+		// installs the http handler for the individual check sub path.
+		subpath := path.Join(reg.RootPath(), checkName)
+		check := checkName
+		mux.Handle(subpath, newHealthHandler(subpath, lg, func(r *http.Request) HealthStatus {
+			return reg.runHealthChecks(r.Context(), check)
+		}))
+	}
+}
+
+func (reg *CheckRegistry) runHealthChecks(ctx context.Context, checkNames ...string) HealthStatus {
+	h := HealthStatus{Status: HealthStatusSuccess}
+	var individualCheckOutput bytes.Buffer
+	for _, checkName := range checkNames {
+		check, found := reg.checks[checkName]
+		if !found {
+			panic(fmt.Errorf("Health check: %s not registered", checkName))
+		}
+		if err := check(ctx); err != nil {
+			fmt.Fprintf(&individualCheckOutput, "[-]%s failed: %v\n", checkName, err)
+			h.Status = HealthStatusError
+			recordMetrics(reg.checkType, checkName, HealthStatusError)
+		} else {
+			fmt.Fprintf(&individualCheckOutput, "[+]%s ok\n", checkName)
+			recordMetrics(reg.checkType, checkName, HealthStatusSuccess)
+		}
+	}
+	h.Reason = individualCheckOutput.String()
+	return h
+}
+
+// installRootHTTPEndpoint installs the http handler for the root path.
+func (reg *CheckRegistry) installRootHTTPEndpoint(lg *zap.Logger, mux *http.ServeMux, checks ...string) {
+	hfunc := func(r *http.Request) HealthStatus {
+		// extracts the health check names to be excludeList from the query param
+		excluded := getQuerySet(r, "exclude")
+
+		filteredCheckNames := filterCheckList(lg, listToStringSet(checks), excluded)
+		h := reg.runHealthChecks(r.Context(), filteredCheckNames...)
+		return h
+	}
+	mux.Handle(reg.RootPath(), newHealthHandler(reg.RootPath(), lg, hfunc))
+}
+
+// newHealthHandler generates a http HandlerFunc for a health check function hfunc.
+func newHealthHandler(path string, lg *zap.Logger, hfunc func(*http.Request) HealthStatus) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != http.MethodGet {
+			w.Header().Set("Allow", http.MethodGet)
+			http.Error(w, "Method Not Allowed", http.StatusMethodNotAllowed)
+			lg.Warn("Health request error", zap.String("path", path), zap.Int("status-code", http.StatusMethodNotAllowed))
+			return
+		}
+		h := hfunc(r)
+		// Always returns detailed reason for failed checks.
+		if h.Status == HealthStatusError {
+			http.Error(w, h.Reason, http.StatusServiceUnavailable)
+			lg.Error("Health check error", zap.String("path", path), zap.String("reason", h.Reason), zap.Int("status-code", http.StatusServiceUnavailable))
+			return
+		}
+		w.Header().Set("Content-Type", "text/plain; charset=utf-8")
+		w.Header().Set("X-Content-Type-Options", "nosniff")
+		// Only writes detailed reason for verbose requests.
+		if _, found := r.URL.Query()["verbose"]; found {
+			fmt.Fprint(w, h.Reason)
+		}
+		fmt.Fprint(w, "ok\n")
+		lg.Debug("Health check OK", zap.String("path", path), zap.String("reason", h.Reason), zap.Int("status-code", http.StatusOK))
+	}
+}
+
+func filterCheckList(lg *zap.Logger, checks StringSet, excluded StringSet) []string {
+	filteredList := []string{}
+	for chk := range checks {
+		if _, found := excluded[chk]; found {
+			delete(excluded, chk)
+			continue
+		}
+		filteredList = append(filteredList, chk)
+	}
+	if len(excluded) > 0 {
+		// For version compatibility, excluding non-exist checks would not fail the request.
+		lg.Warn("some health checks cannot be excluded", zap.String("missing-health-checks", formatQuoted(excluded.List()...)))
+	}
+	return filteredList
+}
+
+// formatQuoted returns a formatted string of the health check names,
+// preserving the order passed in.
+func formatQuoted(names ...string) string {
+	quoted := make([]string, 0, len(names))
+	for _, name := range names {
+		quoted = append(quoted, fmt.Sprintf("%q", name))
+	}
+	return strings.Join(quoted, ",")
+}
+
+type StringSet map[string]struct{}
+
+func (s StringSet) List() []string {
+	keys := make([]string, 0, len(s))
+	for k := range s {
+		keys = append(keys, k)
+	}
+	return keys
+}
+
+func listToStringSet(list []string) StringSet {
+	set := make(map[string]struct{})
+	for _, s := range list {
+		set[s] = struct{}{}
+	}
+	return set
+}
+
+func recordMetrics(checkType, name string, status string) {
+	val := 0.0
+	if status == HealthStatusSuccess {
+		val = 1.0
+	}
+	healthCheckGauge.With(prometheus.Labels{
+		"type": checkType,
+		"name": name,
+	}).Set(val)
+	healthCheckCounter.With(prometheus.Labels{
+		"type":   checkType,
+		"name":   name,
+		"status": status,
+	}).Inc()
+}
+
+// activeAlarmCheck checks if a specific alarm type is active in the server.
+func activeAlarmCheck(srv ServerHealth, at pb.AlarmType) func(context.Context) error {
+	return func(ctx context.Context) error {
+		as := srv.Alarms()
+		for _, v := range as {
+			if v.Alarm == at {
+				return fmt.Errorf("alarm activated: %s", at.String())
+			}
+		}
+		return nil
+	}
+}
+
+func readCheck(srv ServerHealth, serializable bool) func(ctx context.Context) error {
+	return func(ctx context.Context) error {
+		ctx = srv.AuthStore().WithRoot(ctx)
+		_, err := srv.Range(ctx, &pb.RangeRequest{KeysOnly: true, Limit: 1, Serializable: serializable})
+		return err
+	}
+}
+
+func learnerCheck(srv ServerHealth) func(ctx context.Context) error {
+	return func(ctx context.Context) error {
+		if srv.IsLearner() {
+			return fmt.Errorf("not supported for learner")
+		}
+		return nil
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/etcdhttp/metrics.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/etcdhttp/metrics.go
new file mode 100644
index 0000000..bf7d4a4
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/etcdhttp/metrics.go
@@ -0,0 +1,31 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package etcdhttp
+
+import (
+	"net/http"
+
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+)
+
+const (
+	PathMetrics      = "/metrics"
+	PathProxyMetrics = "/proxy/metrics"
+)
+
+// HandleMetrics registers prometheus handler on '/metrics'.
+func HandleMetrics(mux *http.ServeMux) {
+	mux.Handle(PathMetrics, promhttp.Handler())
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/etcdhttp/peer.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/etcdhttp/peer.go
new file mode 100644
index 0000000..de5948d
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/etcdhttp/peer.go
@@ -0,0 +1,165 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package etcdhttp
+
+import (
+	"encoding/json"
+	errorspkg "errors"
+	"fmt"
+	"net/http"
+	"strconv"
+	"strings"
+
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/client/pkg/v3/types"
+	"go.etcd.io/etcd/server/v3/etcdserver"
+	"go.etcd.io/etcd/server/v3/etcdserver/api"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/membership"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp"
+	"go.etcd.io/etcd/server/v3/etcdserver/errors"
+	"go.etcd.io/etcd/server/v3/lease/leasehttp"
+)
+
+const (
+	peerMembersPath         = "/members"
+	peerMemberPromotePrefix = "/members/promote/"
+)
+
+// NewPeerHandler generates an http.Handler to handle etcd peer requests.
+func NewPeerHandler(lg *zap.Logger, s etcdserver.ServerPeerV2) http.Handler {
+	return newPeerHandler(lg, s, s.RaftHandler(), s.LeaseHandler(), s.HashKVHandler(), s.DowngradeEnabledHandler())
+}
+
+func newPeerHandler(
+	lg *zap.Logger,
+	s etcdserver.Server,
+	raftHandler http.Handler,
+	leaseHandler http.Handler,
+	hashKVHandler http.Handler,
+	downgradeEnabledHandler http.Handler,
+) http.Handler {
+	if lg == nil {
+		lg = zap.NewNop()
+	}
+	peerMembersHandler := newPeerMembersHandler(lg, s.Cluster())
+	peerMemberPromoteHandler := newPeerMemberPromoteHandler(lg, s)
+
+	mux := http.NewServeMux()
+	mux.HandleFunc("/", http.NotFound)
+	mux.Handle(rafthttp.RaftPrefix, raftHandler)
+	mux.Handle(rafthttp.RaftPrefix+"/", raftHandler)
+	mux.Handle(peerMembersPath, peerMembersHandler)
+	mux.Handle(peerMemberPromotePrefix, peerMemberPromoteHandler)
+	if leaseHandler != nil {
+		mux.Handle(leasehttp.LeasePrefix, leaseHandler)
+		mux.Handle(leasehttp.LeaseInternalPrefix, leaseHandler)
+	}
+	if downgradeEnabledHandler != nil {
+		mux.Handle(etcdserver.DowngradeEnabledPath, downgradeEnabledHandler)
+	}
+	if hashKVHandler != nil {
+		mux.Handle(etcdserver.PeerHashKVPath, hashKVHandler)
+	}
+	mux.HandleFunc(versionPath, versionHandler(s, serveVersion))
+	return mux
+}
+
+func newPeerMembersHandler(lg *zap.Logger, cluster api.Cluster) http.Handler {
+	return &peerMembersHandler{
+		lg:      lg,
+		cluster: cluster,
+	}
+}
+
+type peerMembersHandler struct {
+	lg      *zap.Logger
+	cluster api.Cluster
+}
+
+func newPeerMemberPromoteHandler(lg *zap.Logger, s etcdserver.Server) http.Handler {
+	return &peerMemberPromoteHandler{
+		lg:      lg,
+		cluster: s.Cluster(),
+		server:  s,
+	}
+}
+
+type peerMemberPromoteHandler struct {
+	lg      *zap.Logger
+	cluster api.Cluster
+	server  etcdserver.Server
+}
+
+func (h *peerMembersHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	if !allowMethod(w, r, "GET") {
+		return
+	}
+	w.Header().Set("X-Etcd-Cluster-ID", h.cluster.ID().String())
+
+	if r.URL.Path != peerMembersPath {
+		http.Error(w, "bad path", http.StatusBadRequest)
+		return
+	}
+	ms := h.cluster.Members()
+	w.Header().Set("Content-Type", "application/json")
+	if err := json.NewEncoder(w).Encode(ms); err != nil {
+		h.lg.Warn("failed to encode membership members", zap.Error(err))
+	}
+}
+
+func (h *peerMemberPromoteHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	if !allowMethod(w, r, "POST") {
+		return
+	}
+	w.Header().Set("X-Etcd-Cluster-ID", h.cluster.ID().String())
+
+	if !strings.HasPrefix(r.URL.Path, peerMemberPromotePrefix) {
+		http.Error(w, "bad path", http.StatusBadRequest)
+		return
+	}
+	idStr := strings.TrimPrefix(r.URL.Path, peerMemberPromotePrefix)
+	id, err := strconv.ParseUint(idStr, 10, 64)
+	if err != nil {
+		http.Error(w, fmt.Sprintf("member %s not found in cluster", idStr), http.StatusNotFound)
+		return
+	}
+
+	resp, err := h.server.PromoteMember(r.Context(), id)
+	if err != nil {
+		switch {
+		case errorspkg.Is(err, membership.ErrIDNotFound):
+			http.Error(w, err.Error(), http.StatusNotFound)
+		case errorspkg.Is(err, membership.ErrMemberNotLearner):
+			http.Error(w, err.Error(), http.StatusPreconditionFailed)
+		case errorspkg.Is(err, errors.ErrLearnerNotReady):
+			http.Error(w, err.Error(), http.StatusPreconditionFailed)
+		default:
+			writeError(h.lg, w, r, err)
+		}
+		h.lg.Warn(
+			"failed to promote a member",
+			zap.String("member-id", types.ID(id).String()),
+			zap.Error(err),
+		)
+		return
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(http.StatusOK)
+	if err := json.NewEncoder(w).Encode(resp); err != nil {
+		h.lg.Warn("failed to encode members response", zap.Error(err))
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/etcdhttp/types/errors.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/etcdhttp/types/errors.go
new file mode 100644
index 0000000..79e366f
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/etcdhttp/types/errors.go
@@ -0,0 +1,51 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package httptypes
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+)
+
+type HTTPError struct {
+	Message string `json:"message"`
+	// Code is the HTTP status code
+	Code int `json:"-"`
+}
+
+func (e HTTPError) Error() string {
+	return e.Message
+}
+
+func (e HTTPError) WriteTo(w http.ResponseWriter) error {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(e.Code)
+	b, err := json.Marshal(e)
+	if err != nil {
+		panic(fmt.Sprintf("failed to marshal HTTPError: %v", err))
+	}
+	if _, err := w.Write(b); err != nil {
+		return err
+	}
+	return nil
+}
+
+func NewHTTPError(code int, m string) *HTTPError {
+	return &HTTPError{
+		Message: m,
+		Code:    code,
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/etcdhttp/utils.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/etcdhttp/utils.go
new file mode 100644
index 0000000..082fa5a
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/etcdhttp/utils.go
@@ -0,0 +1,99 @@
+// Copyright 2022 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package etcdhttp
+
+import (
+	errorspkg "errors"
+	"net/http"
+
+	"go.uber.org/zap"
+
+	httptypes "go.etcd.io/etcd/server/v3/etcdserver/api/etcdhttp/types"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v2error"
+	"go.etcd.io/etcd/server/v3/etcdserver/errors"
+)
+
+func allowMethod(w http.ResponseWriter, r *http.Request, m string) bool {
+	if m == r.Method {
+		return true
+	}
+	w.Header().Set("Allow", m)
+	http.Error(w, "Method Not Allowed", http.StatusMethodNotAllowed)
+	return false
+}
+
+// writeError logs and writes the given Error to the ResponseWriter
+// If Error is an etcdErr, it is rendered to the ResponseWriter
+// Otherwise, it is assumed to be a StatusInternalServerError
+func writeError(lg *zap.Logger, w http.ResponseWriter, r *http.Request, err error) {
+	if err == nil {
+		return
+	}
+	var v2Err *v2error.Error
+	var httpErr *httptypes.HTTPError
+	switch {
+	case errorspkg.As(err, &v2Err):
+		v2Err.WriteTo(w)
+
+	case errorspkg.As(err, &httpErr):
+		if et := httpErr.WriteTo(w); et != nil {
+			if lg != nil {
+				lg.Debug(
+					"failed to write v2 HTTP error",
+					zap.String("remote-addr", r.RemoteAddr),
+					zap.String("internal-server-error", httpErr.Error()),
+					zap.Error(et),
+				)
+			}
+		}
+
+	default:
+		switch {
+		case
+			errorspkg.Is(err, errors.ErrTimeoutDueToLeaderFail),
+			errorspkg.Is(err, errors.ErrTimeoutDueToConnectionLost),
+			errorspkg.Is(err, errors.ErrNotEnoughStartedMembers),
+			errorspkg.Is(err, errors.ErrUnhealthy):
+			if lg != nil {
+				lg.Warn(
+					"v2 response error",
+					zap.String("remote-addr", r.RemoteAddr),
+					zap.String("internal-server-error", err.Error()),
+				)
+			}
+
+		default:
+			if lg != nil {
+				lg.Warn(
+					"unexpected v2 response error",
+					zap.String("remote-addr", r.RemoteAddr),
+					zap.String("internal-server-error", err.Error()),
+				)
+			}
+		}
+
+		herr := httptypes.NewHTTPError(http.StatusInternalServerError, "Internal Server Error")
+		if et := herr.WriteTo(w); et != nil {
+			if lg != nil {
+				lg.Debug(
+					"failed to write v2 HTTP error",
+					zap.String("remote-addr", r.RemoteAddr),
+					zap.String("internal-server-error", err.Error()),
+					zap.Error(et),
+				)
+			}
+		}
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/etcdhttp/version.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/etcdhttp/version.go
new file mode 100644
index 0000000..8090703
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/etcdhttp/version.go
@@ -0,0 +1,65 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package etcdhttp
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+
+	"go.etcd.io/etcd/api/v3/version"
+	"go.etcd.io/etcd/server/v3/etcdserver"
+)
+
+const (
+	versionPath = "/version"
+)
+
+func HandleVersion(mux *http.ServeMux, server etcdserver.Server) {
+	mux.HandleFunc(versionPath, versionHandler(server, serveVersion))
+}
+
+func versionHandler(server etcdserver.Server, fn func(http.ResponseWriter, *http.Request, string, string)) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		clusterVersion := server.ClusterVersion()
+		storageVersion := server.StorageVersion()
+		clusterVersionStr, storageVersionStr := "not_decided", "unknown"
+		if clusterVersion != nil {
+			clusterVersionStr = clusterVersion.String()
+		}
+		if storageVersion != nil {
+			storageVersionStr = storageVersion.String()
+		}
+		fn(w, r, clusterVersionStr, storageVersionStr)
+	}
+}
+
+func serveVersion(w http.ResponseWriter, r *http.Request, clusterV, storageV string) {
+	if !allowMethod(w, r, "GET") {
+		return
+	}
+	vs := version.Versions{
+		Server:  version.Version,
+		Cluster: clusterV,
+		Storage: storageV,
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+	b, err := json.Marshal(&vs)
+	if err != nil {
+		panic(fmt.Sprintf("cannot marshal versions to json (%v)", err))
+	}
+	w.Write(b)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/membership/cluster.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/membership/cluster.go
new file mode 100644
index 0000000..299e613
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/membership/cluster.go
@@ -0,0 +1,1012 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package membership
+
+import (
+	"context"
+	"crypto/sha1"
+	"encoding/binary"
+	"encoding/json"
+	"fmt"
+	"sort"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/coreos/go-semver/semver"
+	"github.com/prometheus/client_golang/prometheus"
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/api/v3/version"
+	"go.etcd.io/etcd/client/pkg/v3/types"
+	"go.etcd.io/etcd/pkg/v3/netutil"
+	"go.etcd.io/etcd/pkg/v3/notify"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v2store"
+	serverversion "go.etcd.io/etcd/server/v3/etcdserver/version"
+	"go.etcd.io/raft/v3"
+	"go.etcd.io/raft/v3/raftpb"
+)
+
+// RaftCluster is a list of Members that belong to the same raft cluster
+type RaftCluster struct {
+	lg *zap.Logger
+
+	localID types.ID
+	cid     types.ID
+
+	v2store v2store.Store
+	be      MembershipBackend
+
+	sync.Mutex // guards the fields below
+	version    *semver.Version
+	members    map[types.ID]*Member
+	// removed contains the ids of removed members in the cluster.
+	// removed id cannot be reused.
+	removed map[types.ID]bool
+
+	downgradeInfo  *serverversion.DowngradeInfo
+	maxLearners    int
+	versionChanged *notify.Notifier
+}
+
+// ConfigChangeContext represents a context for confChange.
+type ConfigChangeContext struct {
+	Member
+	// IsPromote indicates if the config change is for promoting a learner member.
+	// This flag is needed because both adding a new member and promoting a learner member
+	// uses the same config change type 'ConfChangeAddNode'.
+	IsPromote bool `json:"isPromote"`
+}
+
+type ShouldApplyV3 bool
+
+const (
+	ApplyBoth        = ShouldApplyV3(true)
+	ApplyV2storeOnly = ShouldApplyV3(false)
+)
+
+// NewClusterFromURLsMap creates a new raft cluster using provided urls map. Currently, it does not support creating
+// cluster with raft learner member.
+func NewClusterFromURLsMap(lg *zap.Logger, token string, urlsmap types.URLsMap, opts ...ClusterOption) (*RaftCluster, error) {
+	c := NewCluster(lg, opts...)
+	for name, urls := range urlsmap {
+		m := NewMember(name, urls, token, nil)
+		if _, ok := c.members[m.ID]; ok {
+			return nil, fmt.Errorf("member exists with identical ID %v", m)
+		}
+		if uint64(m.ID) == raft.None {
+			return nil, fmt.Errorf("cannot use %x as member id", raft.None)
+		}
+		c.members[m.ID] = m
+	}
+	c.genID()
+	return c, nil
+}
+
+func NewClusterFromMembers(lg *zap.Logger, id types.ID, membs []*Member, opts ...ClusterOption) *RaftCluster {
+	c := NewCluster(lg, opts...)
+	c.cid = id
+	for _, m := range membs {
+		c.members[m.ID] = m
+	}
+	return c
+}
+
+func NewCluster(lg *zap.Logger, opts ...ClusterOption) *RaftCluster {
+	if lg == nil {
+		lg = zap.NewNop()
+	}
+	clOpts := newClusterOpts(opts...)
+
+	return &RaftCluster{
+		lg:            lg,
+		members:       make(map[types.ID]*Member),
+		removed:       make(map[types.ID]bool),
+		downgradeInfo: &serverversion.DowngradeInfo{Enabled: false},
+		maxLearners:   clOpts.maxLearners,
+	}
+}
+
+func (c *RaftCluster) ID() types.ID { return c.cid }
+
+func (c *RaftCluster) Members() []*Member {
+	c.Lock()
+	defer c.Unlock()
+	var ms MembersByID
+	for _, m := range c.members {
+		ms = append(ms, m.Clone())
+	}
+	sort.Sort(ms)
+	return ms
+}
+
+func (c *RaftCluster) Member(id types.ID) *Member {
+	c.Lock()
+	defer c.Unlock()
+	return c.members[id].Clone()
+}
+
+func (c *RaftCluster) VotingMembers() []*Member {
+	c.Lock()
+	defer c.Unlock()
+	var ms MembersByID
+	for _, m := range c.members {
+		if !m.IsLearner {
+			ms = append(ms, m.Clone())
+		}
+	}
+	sort.Sort(ms)
+	return ms
+}
+
+// MemberByName returns a Member with the given name if exists.
+// If more than one member has the given name, it will panic.
+func (c *RaftCluster) MemberByName(name string) *Member {
+	c.Lock()
+	defer c.Unlock()
+	var memb *Member
+	for _, m := range c.members {
+		if m.Name == name {
+			if memb != nil {
+				c.lg.Panic("two member with same name found", zap.String("name", name))
+			}
+			memb = m
+		}
+	}
+	return memb.Clone()
+}
+
+func (c *RaftCluster) MemberIDs() []types.ID {
+	c.Lock()
+	defer c.Unlock()
+	var ids []types.ID
+	for _, m := range c.members {
+		ids = append(ids, m.ID)
+	}
+	sort.Sort(types.IDSlice(ids))
+	return ids
+}
+
+func (c *RaftCluster) IsIDRemoved(id types.ID) bool {
+	c.Lock()
+	defer c.Unlock()
+	return c.removed[id]
+}
+
+// PeerURLs returns a list of all peer addresses.
+// The returned list is sorted in ascending lexicographical order.
+func (c *RaftCluster) PeerURLs() []string {
+	c.Lock()
+	defer c.Unlock()
+	urls := make([]string, 0)
+	for _, p := range c.members {
+		urls = append(urls, p.PeerURLs...)
+	}
+	sort.Strings(urls)
+	return urls
+}
+
+// ClientURLs returns a list of all client addresses.
+// The returned list is sorted in ascending lexicographical order.
+func (c *RaftCluster) ClientURLs() []string {
+	c.Lock()
+	defer c.Unlock()
+	urls := make([]string, 0)
+	for _, p := range c.members {
+		urls = append(urls, p.ClientURLs...)
+	}
+	sort.Strings(urls)
+	return urls
+}
+
+func (c *RaftCluster) String() string {
+	c.Lock()
+	defer c.Unlock()
+	b := &strings.Builder{}
+	fmt.Fprintf(b, "{ClusterID:%s ", c.cid)
+	var ms []string
+	for _, m := range c.members {
+		ms = append(ms, fmt.Sprintf("%+v", m))
+	}
+	fmt.Fprintf(b, "Members:[%s] ", strings.Join(ms, " "))
+	var ids []string
+	for id := range c.removed {
+		ids = append(ids, id.String())
+	}
+	fmt.Fprintf(b, "RemovedMemberIDs:[%s]}", strings.Join(ids, " "))
+	return b.String()
+}
+
+func (c *RaftCluster) genID() {
+	mIDs := c.MemberIDs()
+	b := make([]byte, 8*len(mIDs))
+	for i, id := range mIDs {
+		binary.BigEndian.PutUint64(b[8*i:], uint64(id))
+	}
+	hash := sha1.Sum(b)
+	c.cid = types.ID(binary.BigEndian.Uint64(hash[:8]))
+}
+
+func (c *RaftCluster) SetID(localID, cid types.ID) {
+	c.localID = localID
+	c.cid = cid
+	c.buildMembershipMetric()
+}
+
+func (c *RaftCluster) SetStore(st v2store.Store) { c.v2store = st }
+
+func (c *RaftCluster) SetBackend(be MembershipBackend) {
+	c.be = be
+	c.be.MustCreateBackendBuckets()
+}
+
+func (c *RaftCluster) SetVersionChangedNotifier(n *notify.Notifier) {
+	c.versionChanged = n
+}
+
+func (c *RaftCluster) UnsafeLoad() {
+	if c.be != nil {
+		c.version = c.be.ClusterVersionFromBackend()
+		c.members, c.removed = c.be.MustReadMembersFromBackend()
+	} else {
+		c.version = clusterVersionFromStore(c.lg, c.v2store)
+		c.members, c.removed = membersFromStore(c.lg, c.v2store)
+	}
+
+	if c.be != nil {
+		c.downgradeInfo = c.be.DowngradeInfoFromBackend()
+	}
+}
+
+func (c *RaftCluster) Recover(onSet func(*zap.Logger, *semver.Version)) {
+	c.Lock()
+	defer c.Unlock()
+
+	c.UnsafeLoad()
+
+	c.buildMembershipMetric()
+
+	sv := semver.Must(semver.NewVersion(version.Version))
+	if c.downgradeInfo != nil && c.downgradeInfo.Enabled {
+		c.lg.Info(
+			"cluster is downgrading to target version",
+			zap.String("target-cluster-version", c.downgradeInfo.TargetVersion),
+			zap.String("current-server-version", sv.String()),
+		)
+	}
+	serverversion.MustDetectDowngrade(c.lg, sv, c.version)
+	onSet(c.lg, c.version)
+
+	for _, m := range c.members {
+		if c.localID == m.ID {
+			setIsLearnerMetric(m)
+		}
+
+		c.lg.Info(
+			"recovered/added member from store",
+			zap.String("cluster-id", c.cid.String()),
+			zap.String("local-member-id", c.localID.String()),
+			zap.String("recovered-remote-peer-id", m.ID.String()),
+			zap.Strings("recovered-remote-peer-urls", m.PeerURLs),
+			zap.Bool("recovered-remote-peer-is-learner", m.IsLearner),
+		)
+	}
+	if c.version != nil {
+		c.lg.Info(
+			"set cluster version from store",
+			zap.String("cluster-version", version.Cluster(c.version.String())),
+		)
+	}
+}
+
+// ValidateConfigurationChange takes a proposed ConfChange and
+// ensures that it is still valid.
+func (c *RaftCluster) ValidateConfigurationChange(cc raftpb.ConfChange, shouldApplyV3 ShouldApplyV3) error {
+	var membersMap map[types.ID]*Member
+	var removedMap map[types.ID]bool
+
+	if shouldApplyV3 {
+		membersMap, removedMap = c.be.MustReadMembersFromBackend()
+	} else {
+		membersMap, removedMap = membersFromStore(c.lg, c.v2store)
+	}
+
+	id := types.ID(cc.NodeID)
+	if removedMap[id] {
+		return ErrIDRemoved
+	}
+	switch cc.Type {
+	case raftpb.ConfChangeAddNode, raftpb.ConfChangeAddLearnerNode:
+		confChangeContext := new(ConfigChangeContext)
+		if err := json.Unmarshal(cc.Context, confChangeContext); err != nil {
+			c.lg.Panic("failed to unmarshal confChangeContext", zap.Error(err))
+		}
+
+		if confChangeContext.IsPromote { // promoting a learner member to voting member
+			if membersMap[id] == nil {
+				return ErrIDNotFound
+			}
+			if !membersMap[id].IsLearner {
+				return ErrMemberNotLearner
+			}
+		} else { // adding a new member
+			if membersMap[id] != nil {
+				return ErrIDExists
+			}
+
+			var members []*Member
+			urls := make(map[string]bool)
+			for _, m := range membersMap {
+				members = append(members, m)
+				for _, u := range m.PeerURLs {
+					urls[u] = true
+				}
+			}
+			for _, u := range confChangeContext.Member.PeerURLs {
+				if urls[u] {
+					return ErrPeerURLexists
+				}
+			}
+
+			if confChangeContext.Member.RaftAttributes.IsLearner && cc.Type == raftpb.ConfChangeAddLearnerNode { // the new member is a learner
+				scaleUpLearners := true
+				if err := ValidateMaxLearnerConfig(c.maxLearners, members, scaleUpLearners); err != nil {
+					return err
+				}
+			}
+		}
+	case raftpb.ConfChangeRemoveNode:
+		if membersMap[id] == nil {
+			return ErrIDNotFound
+		}
+
+	case raftpb.ConfChangeUpdateNode:
+		if membersMap[id] == nil {
+			return ErrIDNotFound
+		}
+		urls := make(map[string]bool)
+		for _, m := range membersMap {
+			if m.ID == id {
+				continue
+			}
+			for _, u := range m.PeerURLs {
+				urls[u] = true
+			}
+		}
+		m := new(Member)
+		if err := json.Unmarshal(cc.Context, m); err != nil {
+			c.lg.Panic("failed to unmarshal member", zap.Error(err))
+		}
+		for _, u := range m.PeerURLs {
+			if urls[u] {
+				return ErrPeerURLexists
+			}
+		}
+
+	default:
+		c.lg.Panic("unknown ConfChange type", zap.String("type", cc.Type.String()))
+	}
+	return nil
+}
+
+// AddMember adds a new Member into the cluster, and saves the given member's
+// raftAttributes into the store. The given member should have empty attributes.
+// A Member with a matching id must not exist.
+func (c *RaftCluster) AddMember(m *Member, shouldApplyV3 ShouldApplyV3) {
+	c.Lock()
+	defer c.Unlock()
+	if c.v2store != nil {
+		mustSaveMemberToStore(c.lg, c.v2store, m)
+	}
+
+	if m.ID == c.localID {
+		setIsLearnerMetric(m)
+	}
+
+	if c.be != nil && shouldApplyV3 {
+		c.be.MustSaveMemberToBackend(m)
+
+		c.members[m.ID] = m
+		c.updateMembershipMetric(m.ID, true)
+
+		c.lg.Info(
+			"added member",
+			zap.String("cluster-id", c.cid.String()),
+			zap.String("local-member-id", c.localID.String()),
+			zap.String("added-peer-id", m.ID.String()),
+			zap.Strings("added-peer-peer-urls", m.PeerURLs),
+			zap.Bool("added-peer-is-learner", m.IsLearner),
+		)
+	} else {
+		c.lg.Info(
+			"ignore already added member",
+			zap.String("cluster-id", c.cid.String()),
+			zap.String("local-member-id", c.localID.String()),
+			zap.String("added-peer-id", m.ID.String()),
+			zap.Strings("added-peer-peer-urls", m.PeerURLs),
+			zap.Bool("added-peer-is-learner", m.IsLearner))
+	}
+}
+
+// RemoveMember removes a member from the store.
+// The given id MUST exist, or the function panics.
+func (c *RaftCluster) RemoveMember(id types.ID, shouldApplyV3 ShouldApplyV3) {
+	c.Lock()
+	defer c.Unlock()
+	if c.v2store != nil {
+		mustDeleteMemberFromStore(c.lg, c.v2store, id)
+	}
+	if c.be != nil && shouldApplyV3 {
+		c.be.MustDeleteMemberFromBackend(id)
+
+		m, ok := c.members[id]
+		delete(c.members, id)
+		c.removed[id] = true
+		c.updateMembershipMetric(id, false)
+
+		if ok {
+			c.lg.Info(
+				"removed member",
+				zap.String("cluster-id", c.cid.String()),
+				zap.String("local-member-id", c.localID.String()),
+				zap.String("removed-remote-peer-id", id.String()),
+				zap.Strings("removed-remote-peer-urls", m.PeerURLs),
+				zap.Bool("removed-remote-peer-is-learner", m.IsLearner),
+			)
+		} else {
+			c.lg.Warn(
+				"skipped removing already removed member",
+				zap.String("cluster-id", c.cid.String()),
+				zap.String("local-member-id", c.localID.String()),
+				zap.String("removed-remote-peer-id", id.String()),
+			)
+		}
+	} else {
+		c.lg.Info(
+			"ignore already removed member",
+			zap.String("cluster-id", c.cid.String()),
+			zap.String("local-member-id", c.localID.String()),
+			zap.String("removed-remote-peer-id", id.String()),
+		)
+	}
+}
+
+func (c *RaftCluster) UpdateAttributes(id types.ID, attr Attributes, shouldApplyV3 ShouldApplyV3) {
+	c.Lock()
+	defer c.Unlock()
+
+	if m, ok := c.members[id]; ok {
+		m.Attributes = attr
+		if c.v2store != nil {
+			mustUpdateMemberAttrInStore(c.lg, c.v2store, m)
+		}
+		if c.be != nil && shouldApplyV3 {
+			c.be.MustSaveMemberToBackend(m)
+		}
+		return
+	}
+
+	_, ok := c.removed[id]
+	if !ok {
+		c.lg.Panic(
+			"failed to update; member unknown",
+			zap.String("cluster-id", c.cid.String()),
+			zap.String("local-member-id", c.localID.String()),
+			zap.String("unknown-remote-peer-id", id.String()),
+		)
+	}
+
+	c.lg.Warn(
+		"skipped attributes update of removed member",
+		zap.String("cluster-id", c.cid.String()),
+		zap.String("local-member-id", c.localID.String()),
+		zap.String("updated-peer-id", id.String()),
+	)
+}
+
+// PromoteMember marks the member's IsLearner RaftAttributes to false.
+func (c *RaftCluster) PromoteMember(id types.ID, shouldApplyV3 ShouldApplyV3) {
+	c.Lock()
+	defer c.Unlock()
+
+	if c.v2store != nil {
+		membersMap, _ := membersFromStore(c.lg, c.v2store)
+		if _, ok := membersMap[id]; ok {
+			m := *(membersMap[id])
+			m.RaftAttributes.IsLearner = false
+			mustUpdateMemberInStore(c.lg, c.v2store, &m)
+		} else {
+			c.lg.Info("Skipped promoting non-existent member in v2store",
+				zap.String("cluster-id", c.cid.String()),
+				zap.String("local-member-id", c.localID.String()),
+				zap.String("promoted-member-id", id.String()),
+			)
+		}
+	}
+
+	if id == c.localID {
+		isLearner.Set(0)
+	}
+
+	if c.be != nil {
+		m := c.members[id]
+		if shouldApplyV3 {
+			m.RaftAttributes.IsLearner = false
+			c.updateMembershipMetric(id, true)
+			c.be.MustSaveMemberToBackend(m)
+
+			c.lg.Info(
+				"promote member",
+				zap.String("cluster-id", c.cid.String()),
+				zap.String("local-member-id", c.localID.String()),
+				zap.String("promoted-member-id", id.String()),
+			)
+		} else {
+			// Workaround the issues which have already been affected by
+			// https://github.com/etcd-io/etcd/issues/19557. The learner
+			// promotion request had been applied to v3store, but not saved
+			// to v2snapshot yet when in 3.5. Once upgrading to 3.6, the
+			// patch here ensure the issue can be automatically fixed.
+			if m == nil {
+				c.lg.Info(
+					"Skipped forcibly promoting non-existent member in v3store",
+					zap.String("cluster-id", c.cid.String()),
+					zap.String("local-member-id", c.localID.String()),
+					zap.String("promoted-member-id", id.String()),
+				)
+			} else if m.IsLearner {
+				m.RaftAttributes.IsLearner = false
+				c.lg.Info("Forcibly apply member promotion request in v3store", zap.String("member", fmt.Sprintf("%+v", *m)))
+				c.be.MustHackySaveMemberToBackend(m)
+			} else {
+				c.lg.Info(
+					"ignore already promoted member in v3store",
+					zap.String("cluster-id", c.cid.String()),
+					zap.String("local-member-id", c.localID.String()),
+					zap.String("promoted-member-id", id.String()),
+				)
+			}
+		}
+	} else {
+		c.lg.Info(
+			"ignore already promoted member due to backend being nil",
+			zap.String("cluster-id", c.cid.String()),
+			zap.String("local-member-id", c.localID.String()),
+			zap.String("promoted-member-id", id.String()),
+		)
+	}
+}
+
+// SyncLearnerPromotionIfNeeded provides a workaround solution to fix the issues
+// which have already been affected by https://github.com/etcd-io/etcd/issues/19557.
+func (c *RaftCluster) SyncLearnerPromotionIfNeeded() {
+	c.Lock()
+	defer c.Unlock()
+
+	v2Members, _ := membersFromStore(c.lg, c.v2store)
+	v3Members, _ := c.be.MustReadMembersFromBackend()
+
+	for id, v3Member := range v3Members {
+		v2Member, ok := v2Members[id]
+		if !ok {
+			// This isn't an error. The conf change on the member hasn't been saved to the v2 snapshot yet.
+			c.lg.Info("Detected member only in v3store but missing in v2store", zap.String("member", fmt.Sprintf("%+v", *v3Member)))
+			continue
+		}
+
+		if !v2Member.IsLearner && v3Member.IsLearner {
+			syncedV3Member := v3Member.Clone()
+			syncedV3Member.IsLearner = false
+			c.lg.Warn("Syncing member in v3store", zap.String("member", fmt.Sprintf("%+v", *syncedV3Member)))
+			c.be.MustHackySaveMemberToBackend(syncedV3Member)
+		}
+	}
+}
+
+func (c *RaftCluster) UpdateRaftAttributes(id types.ID, raftAttr RaftAttributes, shouldApplyV3 ShouldApplyV3) {
+	c.Lock()
+	defer c.Unlock()
+
+	if c.v2store != nil {
+		if _, ok := c.members[id]; ok {
+			m := *(c.members[id])
+			m.RaftAttributes = raftAttr
+			mustUpdateMemberInStore(c.lg, c.v2store, &m)
+		} else {
+			c.lg.Info("Skipped updating non-existent member in v2store",
+				zap.String("cluster-id", c.cid.String()),
+				zap.String("local-member-id", c.localID.String()),
+				zap.String("updated-remote-peer-id", id.String()),
+				zap.Strings("updated-remote-peer-urls", raftAttr.PeerURLs),
+				zap.Bool("updated-remote-peer-is-learner", raftAttr.IsLearner),
+			)
+		}
+	}
+	if c.be != nil && shouldApplyV3 {
+		c.members[id].RaftAttributes = raftAttr
+		c.be.MustSaveMemberToBackend(c.members[id])
+
+		c.lg.Info(
+			"updated member",
+			zap.String("cluster-id", c.cid.String()),
+			zap.String("local-member-id", c.localID.String()),
+			zap.String("updated-remote-peer-id", id.String()),
+			zap.Strings("updated-remote-peer-urls", raftAttr.PeerURLs),
+			zap.Bool("updated-remote-peer-is-learner", raftAttr.IsLearner),
+		)
+	} else {
+		c.lg.Info(
+			"ignored already updated member",
+			zap.String("cluster-id", c.cid.String()),
+			zap.String("local-member-id", c.localID.String()),
+			zap.String("updated-remote-peer-id", id.String()),
+			zap.Strings("updated-remote-peer-urls", raftAttr.PeerURLs),
+			zap.Bool("updated-remote-peer-is-learner", raftAttr.IsLearner),
+		)
+	}
+}
+
+func (c *RaftCluster) Version() *semver.Version {
+	c.Lock()
+	defer c.Unlock()
+	if c.version == nil {
+		return nil
+	}
+	return semver.Must(semver.NewVersion(c.version.String()))
+}
+
+func (c *RaftCluster) SetVersion(ver *semver.Version, onSet func(*zap.Logger, *semver.Version), shouldApplyV3 ShouldApplyV3) {
+	c.Lock()
+	defer c.Unlock()
+	if c.version != nil {
+		c.lg.Info(
+			"updated cluster version",
+			zap.String("cluster-id", c.cid.String()),
+			zap.String("local-member-id", c.localID.String()),
+			zap.String("from", version.Cluster(c.version.String())),
+			zap.String("to", version.Cluster(ver.String())),
+		)
+	} else {
+		c.lg.Info(
+			"set initial cluster version",
+			zap.String("cluster-id", c.cid.String()),
+			zap.String("local-member-id", c.localID.String()),
+			zap.String("cluster-version", version.Cluster(ver.String())),
+		)
+	}
+	oldVer := c.version
+	c.version = ver
+	sv := semver.Must(semver.NewVersion(version.Version))
+	serverversion.MustDetectDowngrade(c.lg, sv, c.version)
+	if c.v2store != nil {
+		mustSaveClusterVersionToStore(c.lg, c.v2store, ver)
+	}
+	if c.be != nil && shouldApplyV3 {
+		c.be.MustSaveClusterVersionToBackend(ver)
+	}
+	if oldVer != nil {
+		ClusterVersionMetrics.With(prometheus.Labels{"cluster_version": version.Cluster(oldVer.String())}).Set(0)
+	}
+	ClusterVersionMetrics.With(prometheus.Labels{"cluster_version": version.Cluster(ver.String())}).Set(1)
+	if c.versionChanged != nil {
+		c.versionChanged.Notify()
+	}
+	onSet(c.lg, ver)
+}
+
+func (c *RaftCluster) IsReadyToAddVotingMember() bool {
+	nmembers := 1
+	nstarted := 0
+
+	for _, member := range c.VotingMembers() {
+		if member.IsStarted() {
+			nstarted++
+		}
+		nmembers++
+	}
+
+	if nstarted == 1 && nmembers == 2 {
+		// a case of adding a new node to 1-member cluster for restoring cluster data
+		// https://github.com/etcd-io/website/blob/main/content/docs/v2/admin_guide.md#restoring-the-cluster
+		c.lg.Debug("number of started member is 1; can accept add member request")
+		return true
+	}
+
+	nquorum := nmembers/2 + 1
+	if nstarted < nquorum {
+		c.lg.Warn(
+			"rejecting member add; started member will be less than quorum",
+			zap.Int("number-of-started-member", nstarted),
+			zap.Int("quorum", nquorum),
+			zap.String("cluster-id", c.cid.String()),
+			zap.String("local-member-id", c.localID.String()),
+		)
+		return false
+	}
+
+	return true
+}
+
+func (c *RaftCluster) IsReadyToRemoveVotingMember(id uint64) bool {
+	nmembers := 0
+	nstarted := 0
+
+	for _, member := range c.VotingMembers() {
+		if uint64(member.ID) == id {
+			continue
+		}
+
+		if member.IsStarted() {
+			nstarted++
+		}
+		nmembers++
+	}
+
+	nquorum := nmembers/2 + 1
+	if nstarted < nquorum {
+		c.lg.Warn(
+			"rejecting member remove; started member will be less than quorum",
+			zap.Int("number-of-started-member", nstarted),
+			zap.Int("quorum", nquorum),
+			zap.String("cluster-id", c.cid.String()),
+			zap.String("local-member-id", c.localID.String()),
+		)
+		return false
+	}
+
+	return true
+}
+
+func (c *RaftCluster) IsReadyToPromoteMember(id uint64) bool {
+	nmembers := 1 // We count the learner to be promoted for the future quorum
+	nstarted := 1 // and we also count it as started.
+
+	for _, member := range c.VotingMembers() {
+		if member.IsStarted() {
+			nstarted++
+		}
+		nmembers++
+	}
+
+	nquorum := nmembers/2 + 1
+	if nstarted < nquorum {
+		c.lg.Warn(
+			"rejecting member promote; started member will be less than quorum",
+			zap.Int("number-of-started-member", nstarted),
+			zap.Int("quorum", nquorum),
+			zap.String("cluster-id", c.cid.String()),
+			zap.String("local-member-id", c.localID.String()),
+		)
+		return false
+	}
+
+	return true
+}
+
+func (c *RaftCluster) MembersFromBackend() (map[types.ID]*Member, map[types.ID]bool) {
+	return c.be.MustReadMembersFromBackend()
+}
+
+func (c *RaftCluster) MembersFromStore() (map[types.ID]*Member, map[types.ID]bool) {
+	return membersFromStore(c.lg, c.v2store)
+}
+
+func membersFromStore(lg *zap.Logger, st v2store.Store) (map[types.ID]*Member, map[types.ID]bool) {
+	members := make(map[types.ID]*Member)
+	removed := make(map[types.ID]bool)
+	e, err := st.Get(StoreMembersPrefix, true, true)
+	if err != nil {
+		if isKeyNotFound(err) {
+			return members, removed
+		}
+		lg.Panic("failed to get members from store", zap.String("path", StoreMembersPrefix), zap.Error(err))
+	}
+	for _, n := range e.Node.Nodes {
+		var m *Member
+		m, err = nodeToMember(lg, n)
+		if err != nil {
+			lg.Panic("failed to nodeToMember", zap.Error(err))
+		}
+		members[m.ID] = m
+	}
+
+	e, err = st.Get(storeRemovedMembersPrefix, true, true)
+	if err != nil {
+		if isKeyNotFound(err) {
+			return members, removed
+		}
+		lg.Panic(
+			"failed to get removed members from store",
+			zap.String("path", storeRemovedMembersPrefix),
+			zap.Error(err),
+		)
+	}
+	for _, n := range e.Node.Nodes {
+		removed[MustParseMemberIDFromKey(lg, n.Key)] = true
+	}
+	return members, removed
+}
+
+// ValidateClusterAndAssignIDs validates the local cluster by matching the PeerURLs
+// with the existing cluster. If the validation succeeds, it assigns the IDs
+// from the existing cluster to the local cluster.
+// If the validation fails, an error will be returned.
+func ValidateClusterAndAssignIDs(lg *zap.Logger, local *RaftCluster, existing *RaftCluster) error {
+	ems := existing.Members()
+	lms := local.Members()
+	if len(ems) != len(lms) {
+		return fmt.Errorf("member count is unequal")
+	}
+
+	ctx, cancel := context.WithTimeout(context.TODO(), 30*time.Second)
+	defer cancel()
+	for i := range ems {
+		var err error
+		ok := false
+		for j := range lms {
+			if ok, err = netutil.URLStringsEqual(ctx, lg, ems[i].PeerURLs, lms[j].PeerURLs); ok {
+				lms[j].ID = ems[i].ID
+				break
+			}
+		}
+		if !ok {
+			return fmt.Errorf("PeerURLs: no match found for existing member (%v, %v), last resolver error (%w)", ems[i].ID, ems[i].PeerURLs, err)
+		}
+	}
+	local.members = make(map[types.ID]*Member)
+	for _, m := range lms {
+		local.members[m.ID] = m
+	}
+	local.buildMembershipMetric()
+	return nil
+}
+
+// IsLocalMemberLearner returns if the local member is raft learner
+func (c *RaftCluster) IsLocalMemberLearner() bool {
+	c.Lock()
+	defer c.Unlock()
+	localMember, ok := c.members[c.localID]
+	if !ok {
+		c.lg.Panic(
+			"failed to find local ID in cluster members",
+			zap.String("cluster-id", c.cid.String()),
+			zap.String("local-member-id", c.localID.String()),
+		)
+	}
+	return localMember.IsLearner
+}
+
+// DowngradeInfo returns the downgrade status of the cluster
+func (c *RaftCluster) DowngradeInfo() *serverversion.DowngradeInfo {
+	c.Lock()
+	defer c.Unlock()
+	if c.downgradeInfo == nil {
+		return &serverversion.DowngradeInfo{Enabled: false}
+	}
+	d := &serverversion.DowngradeInfo{Enabled: c.downgradeInfo.Enabled, TargetVersion: c.downgradeInfo.TargetVersion}
+	return d
+}
+
+func (c *RaftCluster) SetDowngradeInfo(d *serverversion.DowngradeInfo, shouldApplyV3 ShouldApplyV3) {
+	c.Lock()
+	defer c.Unlock()
+
+	if c.be != nil && shouldApplyV3 {
+		c.be.MustSaveDowngradeToBackend(d)
+	}
+
+	c.downgradeInfo = d
+}
+
+// IsMemberExist returns if the member with the given id exists in cluster.
+func (c *RaftCluster) IsMemberExist(id types.ID) bool {
+	c.Lock()
+	_, ok := c.members[id]
+	c.Unlock()
+
+	// gofail: var afterIsMemberExist struct{}
+	return ok
+}
+
+// VotingMemberIDs returns the ID of voting members in cluster.
+func (c *RaftCluster) VotingMemberIDs() []types.ID {
+	c.Lock()
+	defer c.Unlock()
+	var ids []types.ID
+	for _, m := range c.members {
+		if !m.IsLearner {
+			ids = append(ids, m.ID)
+		}
+	}
+	sort.Sort(types.IDSlice(ids))
+	return ids
+}
+
+// buildMembershipMetric sets the knownPeers metric based on the current
+// members of the cluster.
+func (c *RaftCluster) buildMembershipMetric() {
+	if c.localID == 0 {
+		// We don't know our own id yet.
+		return
+	}
+	for p := range c.members {
+		knownPeers.WithLabelValues(c.localID.String(), p.String()).Set(1)
+	}
+	for p := range c.removed {
+		knownPeers.WithLabelValues(c.localID.String(), p.String()).Set(0)
+	}
+}
+
+// updateMembershipMetric updates the knownPeers metric to indicate that
+// the given peer is now (un)known.
+func (c *RaftCluster) updateMembershipMetric(peer types.ID, known bool) {
+	if c.localID == 0 {
+		// We don't know our own id yet.
+		return
+	}
+	v := float64(0)
+	if known {
+		v = 1
+	}
+	knownPeers.WithLabelValues(c.localID.String(), peer.String()).Set(v)
+}
+
+// ValidateMaxLearnerConfig verifies the existing learner members in the cluster membership and an optional N+1 learner
+// scale up are not more than maxLearners.
+func ValidateMaxLearnerConfig(maxLearners int, members []*Member, scaleUpLearners bool) error {
+	numLearners := 0
+	for _, m := range members {
+		if m.IsLearner {
+			numLearners++
+		}
+	}
+	// Validate config can accommodate scale up.
+	if scaleUpLearners {
+		numLearners++
+	}
+
+	if numLearners > maxLearners {
+		return ErrTooManyLearners
+	}
+
+	return nil
+}
+
+func (c *RaftCluster) Store(store v2store.Store) {
+	c.Lock()
+	defer c.Unlock()
+
+	verifyNoMembersInStore(c.lg, store)
+
+	for _, m := range c.members {
+		mustSaveMemberToStore(c.lg, store, m)
+		if m.ClientURLs != nil {
+			mustUpdateMemberAttrInStore(c.lg, store, m)
+		}
+		c.lg.Debug(
+			"snapshot storing member",
+			zap.String("id", m.ID.String()),
+			zap.Strings("peer-urls", m.PeerURLs),
+			zap.Bool("is-learner", m.IsLearner),
+		)
+	}
+	for id := range c.removed {
+		// We do not need to delete the member since the store is empty.
+		mustAddToRemovedMembersInStore(c.lg, store, id)
+	}
+	if c.version != nil {
+		mustSaveClusterVersionToStore(c.lg, store, c.version)
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/membership/cluster_opts.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/membership/cluster_opts.go
new file mode 100644
index 0000000..204fbf0
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/membership/cluster_opts.go
@@ -0,0 +1,43 @@
+// Copyright 2021 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package membership
+
+const DefaultMaxLearners = 1
+
+type ClusterOptions struct {
+	maxLearners int
+}
+
+// ClusterOption are options which can be applied to the raft cluster.
+type ClusterOption func(*ClusterOptions)
+
+func newClusterOpts(opts ...ClusterOption) *ClusterOptions {
+	clOpts := &ClusterOptions{}
+	clOpts.applyOpts(opts)
+	return clOpts
+}
+
+func (co *ClusterOptions) applyOpts(opts []ClusterOption) {
+	for _, opt := range opts {
+		opt(co)
+	}
+}
+
+// WithMaxLearners sets the maximum number of learners that can exist in the cluster membership.
+func WithMaxLearners(max int) ClusterOption {
+	return func(co *ClusterOptions) {
+		co.maxLearners = max
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/membership/doc.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/membership/doc.go
new file mode 100644
index 0000000..b07fb2d
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/membership/doc.go
@@ -0,0 +1,16 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package membership describes individual etcd members and clusters of members.
+package membership
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/membership/errors.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/membership/errors.go
new file mode 100644
index 0000000..ff68297
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/membership/errors.go
@@ -0,0 +1,35 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package membership
+
+import (
+	"errors"
+
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v2error"
+)
+
+var (
+	ErrIDRemoved        = errors.New("membership: ID removed")
+	ErrIDExists         = errors.New("membership: ID exists")
+	ErrIDNotFound       = errors.New("membership: ID not found")
+	ErrPeerURLexists    = errors.New("membership: peerURL exists")
+	ErrMemberNotLearner = errors.New("membership: can only promote a learner member")
+	ErrTooManyLearners  = errors.New("membership: too many learner members in cluster")
+)
+
+func isKeyNotFound(err error) bool {
+	var e *v2error.Error
+	return errors.As(err, &e) && e.ErrorCode == v2error.EcodeKeyNotFound
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/membership/member.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/membership/member.go
new file mode 100644
index 0000000..b6037bf
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/membership/member.go
@@ -0,0 +1,132 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package membership
+
+import (
+	"crypto/sha1"
+	"encoding/binary"
+	"fmt"
+	"sort"
+	"strings"
+	"time"
+
+	"go.etcd.io/etcd/client/pkg/v3/types"
+)
+
+// RaftAttributes represents the raft related attributes of an etcd member.
+type RaftAttributes struct {
+	// PeerURLs is the list of peers in the raft cluster.
+	// TODO(philips): ensure these are URLs
+	PeerURLs []string `json:"peerURLs"`
+	// IsLearner indicates if the member is raft learner.
+	IsLearner bool `json:"isLearner,omitempty"`
+}
+
+// Attributes represents all the non-raft related attributes of an etcd member.
+type Attributes struct {
+	Name       string   `json:"name,omitempty"`
+	ClientURLs []string `json:"clientURLs,omitempty"`
+}
+
+type Member struct {
+	ID types.ID `json:"id"`
+	RaftAttributes
+	Attributes
+}
+
+// NewMember creates a Member without an ID and generates one based on the
+// cluster name, peer URLs, and time. This is used for bootstrapping/adding new member.
+func NewMember(name string, peerURLs types.URLs, clusterName string, now *time.Time) *Member {
+	memberID := computeMemberID(peerURLs, clusterName, now)
+	return newMember(name, peerURLs, memberID, false)
+}
+
+// NewMemberAsLearner creates a learner Member without an ID and generates one based on the
+// cluster name, peer URLs, and time. This is used for adding new learner member.
+func NewMemberAsLearner(name string, peerURLs types.URLs, clusterName string, now *time.Time) *Member {
+	memberID := computeMemberID(peerURLs, clusterName, now)
+	return newMember(name, peerURLs, memberID, true)
+}
+
+func computeMemberID(peerURLs types.URLs, clusterName string, now *time.Time) types.ID {
+	peerURLstrs := peerURLs.StringSlice()
+	sort.Strings(peerURLstrs)
+	joinedPeerUrls := strings.Join(peerURLstrs, "")
+	b := []byte(joinedPeerUrls)
+
+	b = append(b, []byte(clusterName)...)
+	if now != nil {
+		b = append(b, []byte(fmt.Sprintf("%d", now.Unix()))...)
+	}
+
+	hash := sha1.Sum(b)
+	return types.ID(binary.BigEndian.Uint64(hash[:8]))
+}
+
+func newMember(name string, peerURLs types.URLs, memberID types.ID, isLearner bool) *Member {
+	m := &Member{
+		RaftAttributes: RaftAttributes{
+			PeerURLs:  peerURLs.StringSlice(),
+			IsLearner: isLearner,
+		},
+		Attributes: Attributes{Name: name},
+		ID:         memberID,
+	}
+	return m
+}
+
+func (m *Member) Clone() *Member {
+	if m == nil {
+		return nil
+	}
+	mm := &Member{
+		ID: m.ID,
+		RaftAttributes: RaftAttributes{
+			IsLearner: m.IsLearner,
+		},
+		Attributes: Attributes{
+			Name: m.Name,
+		},
+	}
+	if m.PeerURLs != nil {
+		mm.PeerURLs = make([]string, len(m.PeerURLs))
+		copy(mm.PeerURLs, m.PeerURLs)
+	}
+	if m.ClientURLs != nil {
+		mm.ClientURLs = make([]string, len(m.ClientURLs))
+		copy(mm.ClientURLs, m.ClientURLs)
+	}
+	return mm
+}
+
+func (m *Member) IsStarted() bool {
+	return len(m.Name) != 0
+}
+
+// MembersByID implements sort by ID interface
+type MembersByID []*Member
+
+func (ms MembersByID) Len() int           { return len(ms) }
+func (ms MembersByID) Less(i, j int) bool { return ms[i].ID < ms[j].ID }
+func (ms MembersByID) Swap(i, j int)      { ms[i], ms[j] = ms[j], ms[i] }
+
+// MembersByPeerURLs implements sort by peer urls interface
+type MembersByPeerURLs []*Member
+
+func (ms MembersByPeerURLs) Len() int { return len(ms) }
+func (ms MembersByPeerURLs) Less(i, j int) bool {
+	return ms[i].PeerURLs[0] < ms[j].PeerURLs[0]
+}
+func (ms MembersByPeerURLs) Swap(i, j int) { ms[i], ms[j] = ms[j], ms[i] }
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/membership/metrics.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/membership/metrics.go
new file mode 100644
index 0000000..ad98dbb
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/membership/metrics.go
@@ -0,0 +1,58 @@
+// Copyright 2018 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package membership
+
+import "github.com/prometheus/client_golang/prometheus"
+
+var (
+	ClusterVersionMetrics = prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Namespace: "etcd",
+			Subsystem: "cluster",
+			Name:      "version",
+			Help:      "Which version is running. 1 for 'cluster_version' label with current cluster version",
+		},
+		[]string{"cluster_version"},
+	)
+	knownPeers = prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Namespace: "etcd",
+			Subsystem: "network",
+			Name:      "known_peers",
+			Help:      "The current number of known peers.",
+		},
+		[]string{"Local", "Remote"},
+	)
+	isLearner = prometheus.NewGauge(prometheus.GaugeOpts{
+		Namespace: "etcd",
+		Subsystem: "server",
+		Name:      "is_learner",
+		Help:      "Whether or not this member is a learner. 1 if is, 0 otherwise.",
+	})
+)
+
+func setIsLearnerMetric(m *Member) {
+	if m.IsLearner {
+		isLearner.Set(1)
+	} else {
+		isLearner.Set(0)
+	}
+}
+
+func init() {
+	prometheus.MustRegister(ClusterVersionMetrics)
+	prometheus.MustRegister(knownPeers)
+	prometheus.MustRegister(isLearner)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/membership/store.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/membership/store.go
new file mode 100644
index 0000000..d4bb734
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/membership/store.go
@@ -0,0 +1,58 @@
+// Copyright 2021 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package membership
+
+import (
+	"path"
+
+	"github.com/coreos/go-semver/semver"
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/client/pkg/v3/types"
+	"go.etcd.io/etcd/server/v3/etcdserver/version"
+)
+
+type MembershipBackend interface {
+	ClusterVersionBackend
+	MemberBackend
+	DowngradeInfoBackend
+	MustCreateBackendBuckets()
+}
+
+type ClusterVersionBackend interface {
+	ClusterVersionFromBackend() *semver.Version
+	MustSaveClusterVersionToBackend(version *semver.Version)
+}
+
+type MemberBackend interface {
+	MustReadMembersFromBackend() (map[types.ID]*Member, map[types.ID]bool)
+	MustSaveMemberToBackend(*Member)
+	MustHackySaveMemberToBackend(*Member)
+	TrimMembershipFromBackend() error
+	MustDeleteMemberFromBackend(types.ID)
+}
+
+type DowngradeInfoBackend interface {
+	MustSaveDowngradeToBackend(*version.DowngradeInfo)
+	DowngradeInfoFromBackend() *version.DowngradeInfo
+}
+
+func MustParseMemberIDFromKey(lg *zap.Logger, key string) types.ID {
+	id, err := types.IDFromString(path.Base(key))
+	if err != nil {
+		lg.Panic("failed to parse member id from key", zap.Error(err))
+	}
+	return id
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/membership/storev2.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/membership/storev2.go
new file mode 100644
index 0000000..0511505
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/membership/storev2.go
@@ -0,0 +1,258 @@
+// Copyright 2021 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package membership
+
+import (
+	"encoding/json"
+	"fmt"
+	"path"
+
+	"github.com/coreos/go-semver/semver"
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/client/pkg/v3/types"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v2store"
+)
+
+const (
+	// the prefix for storing membership related information in store provided by store pkg.
+	storePrefix = "/0"
+
+	attributesSuffix     = "attributes"
+	raftAttributesSuffix = "raftAttributes"
+)
+
+var (
+	StoreMembersPrefix        = path.Join(storePrefix, "members")
+	storeRemovedMembersPrefix = path.Join(storePrefix, "removed_members")
+)
+
+// IsMetaStoreOnly verifies if the given `store` contains only
+// a meta-information (members, version) that can be recovered from the
+// backend (storev3) as well as opposed to user-data.
+func IsMetaStoreOnly(store v2store.Store) (bool, error) {
+	event, err := store.Get("/", true, false)
+	if err != nil {
+		return false, err
+	}
+
+	// storePermsPrefix is the internal prefix of the storage layer dedicated to storing user data.
+	// refer to https://github.com/etcd-io/etcd/blob/v3.5.21/server/etcdserver/api/v2auth/auth.go#L40
+	storePermsPrefix := "/2"
+	for _, n := range event.Node.Nodes {
+		if n.Key == storePrefix {
+			continue
+		}
+
+		// For auth data, even after we remove all users and roles, the node
+		// "/2/roles" and "/2/users" are still present in the tree. We need
+		// to exclude such case. See an example below,
+		// Refer to https://github.com/etcd-io/etcd/discussions/20231#discussioncomment-13791940
+		/*
+			"2": {
+				"Path": "/2",
+					"CreatedIndex": 204749,
+					"ModifiedIndex": 204749,
+					"ExpireTime": "0001-01-01T00:00:00Z",
+					"Value": "",
+					"Children": {
+					"enabled": {
+						"Path": "/2/enabled",
+							"CreatedIndex": 204752,
+							"ModifiedIndex": 16546016,
+							"ExpireTime": "0001-01-01T00:00:00Z",
+							"Value": "false",
+							"Children": null
+					},
+					"roles": {
+						"Path": "/2/roles",
+							"CreatedIndex": 204751,
+							"ModifiedIndex": 204751,
+							"ExpireTime": "0001-01-01T00:00:00Z",
+							"Value": "",
+							"Children": {}
+					},
+					"users": {
+						"Path": "/2/users",
+							"CreatedIndex": 204750,
+							"ModifiedIndex": 204750,
+							"ExpireTime": "0001-01-01T00:00:00Z",
+							"Value": "",
+							"Children": {}
+					}
+				}
+			}
+		*/
+		if n.Key == storePermsPrefix {
+			if n.Nodes.Len() > 0 {
+				for _, child := range n.Nodes {
+					if child.Nodes.Len() > 0 {
+						return false, nil
+					}
+				}
+			}
+			continue
+		}
+
+		if n.Nodes.Len() > 0 {
+			return false, nil
+		}
+	}
+
+	return true, nil
+}
+
+func verifyNoMembersInStore(lg *zap.Logger, s v2store.Store) {
+	members, removed := membersFromStore(lg, s)
+	if len(members) != 0 || len(removed) != 0 {
+		lg.Panic("store has membership info")
+	}
+}
+
+func mustSaveMemberToStore(lg *zap.Logger, s v2store.Store, m *Member) {
+	b, err := json.Marshal(m.RaftAttributes)
+	if err != nil {
+		lg.Panic("failed to marshal raftAttributes", zap.Error(err))
+	}
+	p := path.Join(MemberStoreKey(m.ID), raftAttributesSuffix)
+	if _, err := s.Create(p, false, string(b), false, v2store.TTLOptionSet{ExpireTime: v2store.Permanent}); err != nil {
+		lg.Panic(
+			"failed to save member to store",
+			zap.String("path", p),
+			zap.Error(err),
+		)
+	}
+}
+
+func mustDeleteMemberFromStore(lg *zap.Logger, s v2store.Store, id types.ID) {
+	if _, err := s.Delete(MemberStoreKey(id), true, true); err != nil {
+		lg.Panic(
+			"failed to delete member from store",
+			zap.String("path", MemberStoreKey(id)),
+			zap.Error(err),
+		)
+	}
+
+	mustAddToRemovedMembersInStore(lg, s, id)
+}
+
+func mustAddToRemovedMembersInStore(lg *zap.Logger, s v2store.Store, id types.ID) {
+	if _, err := s.Create(RemovedMemberStoreKey(id), false, "", false, v2store.TTLOptionSet{ExpireTime: v2store.Permanent}); err != nil {
+		lg.Panic(
+			"failed to create removedMember",
+			zap.String("path", RemovedMemberStoreKey(id)),
+			zap.Error(err),
+		)
+	}
+}
+
+func mustUpdateMemberInStore(lg *zap.Logger, s v2store.Store, m *Member) {
+	b, err := json.Marshal(m.RaftAttributes)
+	if err != nil {
+		lg.Panic("failed to marshal raftAttributes", zap.Error(err))
+	}
+	p := path.Join(MemberStoreKey(m.ID), raftAttributesSuffix)
+	if _, err := s.Update(p, string(b), v2store.TTLOptionSet{ExpireTime: v2store.Permanent}); err != nil {
+		lg.Panic(
+			"failed to update raftAttributes",
+			zap.String("path", p),
+			zap.Error(err),
+		)
+	}
+}
+
+func mustUpdateMemberAttrInStore(lg *zap.Logger, s v2store.Store, m *Member) {
+	b, err := json.Marshal(m.Attributes)
+	if err != nil {
+		lg.Panic("failed to marshal attributes", zap.Error(err))
+	}
+	p := path.Join(MemberStoreKey(m.ID), attributesSuffix)
+	if _, err := s.Set(p, false, string(b), v2store.TTLOptionSet{ExpireTime: v2store.Permanent}); err != nil {
+		lg.Panic(
+			"failed to update attributes",
+			zap.String("path", p),
+			zap.Error(err),
+		)
+	}
+}
+
+func mustSaveClusterVersionToStore(lg *zap.Logger, s v2store.Store, ver *semver.Version) {
+	if _, err := s.Set(StoreClusterVersionKey(), false, ver.String(), v2store.TTLOptionSet{ExpireTime: v2store.Permanent}); err != nil {
+		lg.Panic(
+			"failed to save cluster version to store",
+			zap.String("path", StoreClusterVersionKey()),
+			zap.Error(err),
+		)
+	}
+}
+
+// nodeToMember builds member from a key value node.
+// the child nodes of the given node MUST be sorted by key.
+func nodeToMember(lg *zap.Logger, n *v2store.NodeExtern) (*Member, error) {
+	m := &Member{ID: MustParseMemberIDFromKey(lg, n.Key)}
+	attrs := make(map[string][]byte)
+	raftAttrKey := path.Join(n.Key, raftAttributesSuffix)
+	attrKey := path.Join(n.Key, attributesSuffix)
+	for _, nn := range n.Nodes {
+		if nn.Key != raftAttrKey && nn.Key != attrKey {
+			return nil, fmt.Errorf("unknown key %q", nn.Key)
+		}
+		attrs[nn.Key] = []byte(*nn.Value)
+	}
+	if data := attrs[raftAttrKey]; data != nil {
+		if err := json.Unmarshal(data, &m.RaftAttributes); err != nil {
+			return nil, fmt.Errorf("unmarshal raftAttributes error: %w", err)
+		}
+	} else {
+		return nil, fmt.Errorf("raftAttributes key doesn't exist")
+	}
+	if data := attrs[attrKey]; data != nil {
+		if err := json.Unmarshal(data, &m.Attributes); err != nil {
+			return m, fmt.Errorf("unmarshal attributes error: %w", err)
+		}
+	}
+	return m, nil
+}
+
+func StoreClusterVersionKey() string {
+	return path.Join(storePrefix, "version")
+}
+
+func RemovedMemberStoreKey(id types.ID) string {
+	return path.Join(storeRemovedMembersPrefix, id.String())
+}
+
+func MemberStoreKey(id types.ID) string {
+	return path.Join(StoreMembersPrefix, id.String())
+}
+
+func MemberAttributesStorePath(id types.ID) string {
+	return path.Join(MemberStoreKey(id), attributesSuffix)
+}
+
+func clusterVersionFromStore(lg *zap.Logger, st v2store.Store) *semver.Version {
+	e, err := st.Get(path.Join(storePrefix, "version"), false, false)
+	if err != nil {
+		if isKeyNotFound(err) {
+			return nil
+		}
+		lg.Panic(
+			"failed to get cluster version from store",
+			zap.String("path", path.Join(storePrefix, "version")),
+			zap.Error(err),
+		)
+	}
+	return semver.Must(semver.NewVersion(*e.Node.Value))
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/coder.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/coder.go
new file mode 100644
index 0000000..9774429
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/coder.go
@@ -0,0 +1,27 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package rafthttp
+
+import "go.etcd.io/raft/v3/raftpb"
+
+type encoder interface {
+	// encode encodes the given message to an output stream.
+	encode(m *raftpb.Message) error
+}
+
+type decoder interface {
+	// decode decodes the message from an input stream.
+	decode() (raftpb.Message, error)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/doc.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/doc.go
new file mode 100644
index 0000000..c45dc81
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/doc.go
@@ -0,0 +1,16 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package rafthttp implements HTTP transportation layer for raft pkg.
+package rafthttp
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/http.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/http.go
new file mode 100644
index 0000000..2610240
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/http.go
@@ -0,0 +1,533 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package rafthttp
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"path"
+	"strings"
+	"time"
+
+	humanize "github.com/dustin/go-humanize"
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/api/v3/version"
+	"go.etcd.io/etcd/client/pkg/v3/types"
+	pioutil "go.etcd.io/etcd/pkg/v3/ioutil"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/snap"
+	"go.etcd.io/raft/v3/raftpb"
+)
+
+const (
+	// connReadLimitByte limits the number of bytes
+	// a single read can read out.
+	//
+	// 64KB should be large enough for not causing
+	// throughput bottleneck as well as small enough
+	// for not causing a read timeout.
+	connReadLimitByte = 64 * 1024
+
+	// snapshotLimitByte limits the snapshot size to 1TB
+	snapshotLimitByte = 1 * 1024 * 1024 * 1024 * 1024
+)
+
+var (
+	RaftPrefix         = "/raft"
+	ProbingPrefix      = path.Join(RaftPrefix, "probing")
+	RaftStreamPrefix   = path.Join(RaftPrefix, "stream")
+	RaftSnapshotPrefix = path.Join(RaftPrefix, "snapshot")
+
+	errIncompatibleVersion = errors.New("incompatible version")
+	ErrClusterIDMismatch   = errors.New("cluster ID mismatch")
+)
+
+type peerGetter interface {
+	Get(id types.ID) Peer
+}
+
+type writerToResponse interface {
+	WriteTo(w http.ResponseWriter)
+}
+
+type pipelineHandler struct {
+	lg      *zap.Logger
+	localID types.ID
+	tr      Transporter
+	r       Raft
+	cid     types.ID
+}
+
+// newPipelineHandler returns a handler for handling raft messages
+// from pipeline for RaftPrefix.
+//
+// The handler reads out the raft message from request body,
+// and forwards it to the given raft state machine for processing.
+func newPipelineHandler(t *Transport, r Raft, cid types.ID) http.Handler {
+	h := &pipelineHandler{
+		lg:      t.Logger,
+		localID: t.ID,
+		tr:      t,
+		r:       r,
+		cid:     cid,
+	}
+	if h.lg == nil {
+		h.lg = zap.NewNop()
+	}
+	return h
+}
+
+func (h *pipelineHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodPost {
+		w.Header().Set("Allow", "POST")
+		http.Error(w, "Method Not Allowed", http.StatusMethodNotAllowed)
+		return
+	}
+
+	w.Header().Set("X-Etcd-Cluster-ID", h.cid.String())
+
+	if err := checkClusterCompatibilityFromHeader(h.lg, h.localID, r.Header, h.cid); err != nil {
+		http.Error(w, err.Error(), http.StatusPreconditionFailed)
+		return
+	}
+
+	addRemoteFromRequest(h.tr, r)
+
+	// Limit the data size that could be read from the request body, which ensures that read from
+	// connection will not time out accidentally due to possible blocking in underlying implementation.
+	limitedr := pioutil.NewLimitedBufferReader(r.Body, connReadLimitByte)
+	b, err := io.ReadAll(limitedr)
+	if err != nil {
+		h.lg.Warn(
+			"failed to read Raft message",
+			zap.String("local-member-id", h.localID.String()),
+			zap.Error(err),
+		)
+		http.Error(w, "error reading raft message", http.StatusBadRequest)
+		recvFailures.WithLabelValues(r.RemoteAddr).Inc()
+		return
+	}
+
+	var m raftpb.Message
+	if err := m.Unmarshal(b); err != nil {
+		h.lg.Warn(
+			"failed to unmarshal Raft message",
+			zap.String("local-member-id", h.localID.String()),
+			zap.Error(err),
+		)
+		http.Error(w, "error unmarshalling raft message", http.StatusBadRequest)
+		recvFailures.WithLabelValues(r.RemoteAddr).Inc()
+		return
+	}
+
+	receivedBytes.WithLabelValues(types.ID(m.From).String()).Add(float64(len(b)))
+
+	if err := h.r.Process(context.TODO(), m); err != nil {
+		var writerErr writerToResponse
+		switch {
+		case errors.As(err, &writerErr):
+			writerErr.WriteTo(w)
+		default:
+			h.lg.Warn(
+				"failed to process Raft message",
+				zap.String("local-member-id", h.localID.String()),
+				zap.Error(err),
+			)
+			http.Error(w, "error processing raft message", http.StatusInternalServerError)
+			w.(http.Flusher).Flush()
+			// disconnect the http stream
+			panic(err)
+		}
+		return
+	}
+
+	// Write StatusNoContent header after the message has been processed by
+	// raft, which facilitates the client to report MsgSnap status.
+	w.WriteHeader(http.StatusNoContent)
+}
+
+type snapshotHandler struct {
+	lg          *zap.Logger
+	tr          Transporter
+	r           Raft
+	snapshotter *snap.Snapshotter
+
+	localID types.ID
+	cid     types.ID
+}
+
+func newSnapshotHandler(t *Transport, r Raft, snapshotter *snap.Snapshotter, cid types.ID) http.Handler {
+	h := &snapshotHandler{
+		lg:          t.Logger,
+		tr:          t,
+		r:           r,
+		snapshotter: snapshotter,
+		localID:     t.ID,
+		cid:         cid,
+	}
+	if h.lg == nil {
+		h.lg = zap.NewNop()
+	}
+	return h
+}
+
+const unknownSnapshotSender = "UNKNOWN_SNAPSHOT_SENDER"
+
+// ServeHTTP serves HTTP request to receive and process snapshot message.
+//
+// If request sender dies without closing underlying TCP connection,
+// the handler will keep waiting for the request body until TCP keepalive
+// finds out that the connection is broken after several minutes.
+// This is acceptable because
+// 1. snapshot messages sent through other TCP connections could still be
+// received and processed.
+// 2. this case should happen rarely, so no further optimization is done.
+func (h *snapshotHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	start := time.Now()
+
+	if r.Method != http.MethodPost {
+		w.Header().Set("Allow", "POST")
+		http.Error(w, "Method Not Allowed", http.StatusMethodNotAllowed)
+		snapshotReceiveFailures.WithLabelValues(unknownSnapshotSender).Inc()
+		return
+	}
+
+	w.Header().Set("X-Etcd-Cluster-ID", h.cid.String())
+
+	if err := checkClusterCompatibilityFromHeader(h.lg, h.localID, r.Header, h.cid); err != nil {
+		http.Error(w, err.Error(), http.StatusPreconditionFailed)
+		snapshotReceiveFailures.WithLabelValues(unknownSnapshotSender).Inc()
+		return
+	}
+
+	addRemoteFromRequest(h.tr, r)
+
+	dec := &messageDecoder{r: r.Body}
+	// let snapshots be very large since they can exceed 512MB for large installations
+	m, err := dec.decodeLimit(snapshotLimitByte)
+	from := types.ID(m.From).String()
+	if err != nil {
+		msg := fmt.Sprintf("failed to decode raft message (%v)", err)
+		h.lg.Warn(
+			"failed to decode Raft message",
+			zap.String("local-member-id", h.localID.String()),
+			zap.String("remote-snapshot-sender-id", from),
+			zap.Error(err),
+		)
+		http.Error(w, msg, http.StatusBadRequest)
+		recvFailures.WithLabelValues(r.RemoteAddr).Inc()
+		snapshotReceiveFailures.WithLabelValues(from).Inc()
+		return
+	}
+
+	msgSize := m.Size()
+	receivedBytes.WithLabelValues(from).Add(float64(msgSize))
+
+	if m.Type != raftpb.MsgSnap {
+		h.lg.Warn(
+			"unexpected Raft message type",
+			zap.String("local-member-id", h.localID.String()),
+			zap.String("remote-snapshot-sender-id", from),
+			zap.String("message-type", m.Type.String()),
+		)
+		http.Error(w, "wrong raft message type", http.StatusBadRequest)
+		snapshotReceiveFailures.WithLabelValues(from).Inc()
+		return
+	}
+
+	snapshotReceiveInflights.WithLabelValues(from).Inc()
+	defer func() {
+		snapshotReceiveInflights.WithLabelValues(from).Dec()
+	}()
+
+	h.lg.Info(
+		"receiving database snapshot",
+		zap.String("local-member-id", h.localID.String()),
+		zap.String("remote-snapshot-sender-id", from),
+		zap.Uint64("incoming-snapshot-index", m.Snapshot.Metadata.Index),
+		zap.Int("incoming-snapshot-message-size-bytes", msgSize),
+		zap.String("incoming-snapshot-message-size", humanize.Bytes(uint64(msgSize))),
+	)
+
+	// save incoming database snapshot.
+
+	n, err := h.snapshotter.SaveDBFrom(r.Body, m.Snapshot.Metadata.Index)
+	if err != nil {
+		msg := fmt.Sprintf("failed to save KV snapshot (%v)", err)
+		h.lg.Warn(
+			"failed to save incoming database snapshot",
+			zap.String("local-member-id", h.localID.String()),
+			zap.String("remote-snapshot-sender-id", from),
+			zap.Uint64("incoming-snapshot-index", m.Snapshot.Metadata.Index),
+			zap.Error(err),
+		)
+		http.Error(w, msg, http.StatusInternalServerError)
+		snapshotReceiveFailures.WithLabelValues(from).Inc()
+		return
+	}
+
+	receivedBytes.WithLabelValues(from).Add(float64(n))
+
+	downloadTook := time.Since(start)
+	h.lg.Info(
+		"received and saved database snapshot",
+		zap.String("local-member-id", h.localID.String()),
+		zap.String("remote-snapshot-sender-id", from),
+		zap.Uint64("incoming-snapshot-index", m.Snapshot.Metadata.Index),
+		zap.Int64("incoming-snapshot-size-bytes", n),
+		zap.String("incoming-snapshot-size", humanize.Bytes(uint64(n))),
+		zap.String("download-took", downloadTook.String()),
+	)
+
+	if err := h.r.Process(context.TODO(), m); err != nil {
+		var writerErr writerToResponse
+		switch {
+		// Process may return writerToResponse error when doing some
+		// additional checks before calling raft.Node.Step.
+		case errors.As(err, &writerErr):
+			writerErr.WriteTo(w)
+		default:
+			msg := fmt.Sprintf("failed to process raft message (%v)", err)
+			h.lg.Warn(
+				"failed to process Raft message",
+				zap.String("local-member-id", h.localID.String()),
+				zap.String("remote-snapshot-sender-id", from),
+				zap.Error(err),
+			)
+			http.Error(w, msg, http.StatusInternalServerError)
+			snapshotReceiveFailures.WithLabelValues(from).Inc()
+		}
+		return
+	}
+
+	// Write StatusNoContent header after the message has been processed by
+	// raft, which facilitates the client to report MsgSnap status.
+	w.WriteHeader(http.StatusNoContent)
+
+	snapshotReceive.WithLabelValues(from).Inc()
+	snapshotReceiveSeconds.WithLabelValues(from).Observe(time.Since(start).Seconds())
+}
+
+type streamHandler struct {
+	lg         *zap.Logger
+	tr         *Transport
+	peerGetter peerGetter
+	r          Raft
+	id         types.ID
+	cid        types.ID
+}
+
+func newStreamHandler(t *Transport, pg peerGetter, r Raft, id, cid types.ID) http.Handler {
+	h := &streamHandler{
+		lg:         t.Logger,
+		tr:         t,
+		peerGetter: pg,
+		r:          r,
+		id:         id,
+		cid:        cid,
+	}
+	if h.lg == nil {
+		h.lg = zap.NewNop()
+	}
+	return h
+}
+
+func (h *streamHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodGet {
+		w.Header().Set("Allow", "GET")
+		http.Error(w, "Method Not Allowed", http.StatusMethodNotAllowed)
+		return
+	}
+
+	w.Header().Set("X-Server-Version", version.Version)
+	w.Header().Set("X-Etcd-Cluster-ID", h.cid.String())
+
+	if err := checkClusterCompatibilityFromHeader(h.lg, h.tr.ID, r.Header, h.cid); err != nil {
+		http.Error(w, err.Error(), http.StatusPreconditionFailed)
+		return
+	}
+
+	var t streamType
+	switch path.Dir(r.URL.Path) {
+	case streamTypeMsgAppV2.endpoint(h.lg):
+		t = streamTypeMsgAppV2
+	case streamTypeMessage.endpoint(h.lg):
+		t = streamTypeMessage
+	default:
+		h.lg.Debug(
+			"ignored unexpected streaming request path",
+			zap.String("local-member-id", h.tr.ID.String()),
+			zap.String("remote-peer-id-stream-handler", h.id.String()),
+			zap.String("path", r.URL.Path),
+		)
+		http.Error(w, "invalid path", http.StatusNotFound)
+		return
+	}
+
+	fromStr := path.Base(r.URL.Path)
+	from, err := types.IDFromString(fromStr)
+	if err != nil {
+		h.lg.Warn(
+			"failed to parse path into ID",
+			zap.String("local-member-id", h.tr.ID.String()),
+			zap.String("remote-peer-id-stream-handler", h.id.String()),
+			zap.String("path", fromStr),
+			zap.Error(err),
+		)
+		http.Error(w, "invalid from", http.StatusNotFound)
+		return
+	}
+	if h.r.IsIDRemoved(uint64(from)) {
+		h.lg.Warn(
+			"rejected stream from remote peer because it was removed",
+			zap.String("local-member-id", h.tr.ID.String()),
+			zap.String("remote-peer-id-stream-handler", h.id.String()),
+			zap.String("remote-peer-id-from", from.String()),
+		)
+		http.Error(w, "removed member", http.StatusGone)
+		return
+	}
+	p := h.peerGetter.Get(from)
+	if p == nil {
+		// This may happen in following cases:
+		// 1. user starts a remote peer that belongs to a different cluster
+		// with the same cluster ID.
+		// 2. local etcd falls behind of the cluster, and cannot recognize
+		// the members that joined after its current progress.
+		if urls := r.Header.Get("X-PeerURLs"); urls != "" {
+			h.tr.AddRemote(from, strings.Split(urls, ","))
+		}
+		h.lg.Warn(
+			"failed to find remote peer in cluster",
+			zap.String("local-member-id", h.tr.ID.String()),
+			zap.String("remote-peer-id-stream-handler", h.id.String()),
+			zap.String("remote-peer-id-from", from.String()),
+			zap.String("cluster-id", h.cid.String()),
+		)
+		http.Error(w, "error sender not found", http.StatusNotFound)
+		return
+	}
+
+	wto := h.id.String()
+	if gto := r.Header.Get("X-Raft-To"); gto != wto {
+		h.lg.Warn(
+			"ignored streaming request; ID mismatch",
+			zap.String("local-member-id", h.tr.ID.String()),
+			zap.String("remote-peer-id-stream-handler", h.id.String()),
+			zap.String("remote-peer-id-header", gto),
+			zap.String("remote-peer-id-from", from.String()),
+			zap.String("cluster-id", h.cid.String()),
+		)
+		http.Error(w, "to field mismatch", http.StatusPreconditionFailed)
+		return
+	}
+
+	w.WriteHeader(http.StatusOK)
+	w.(http.Flusher).Flush()
+
+	c := newCloseNotifier()
+	conn := &outgoingConn{
+		t:       t,
+		Writer:  w,
+		Flusher: w.(http.Flusher),
+		Closer:  c,
+		localID: h.tr.ID,
+		peerID:  from,
+	}
+	p.attachOutgoingConn(conn)
+	<-c.closeNotify()
+}
+
+// checkClusterCompatibilityFromHeader checks the cluster compatibility of
+// the local member from the given header.
+// It checks whether the version of local member is compatible with
+// the versions in the header, and whether the cluster ID of local member
+// matches the one in the header.
+func checkClusterCompatibilityFromHeader(lg *zap.Logger, localID types.ID, header http.Header, cid types.ID) error {
+	remoteName := header.Get("X-Server-From")
+
+	remoteServer := serverVersion(header)
+	remoteVs := ""
+	if remoteServer != nil {
+		remoteVs = remoteServer.String()
+	}
+
+	remoteMinClusterVer := minClusterVersion(header)
+	remoteMinClusterVs := ""
+	if remoteMinClusterVer != nil {
+		remoteMinClusterVs = remoteMinClusterVer.String()
+	}
+
+	localServer, localMinCluster, err := checkVersionCompatibility(remoteName, remoteServer, remoteMinClusterVer)
+
+	localVs := ""
+	if localServer != nil {
+		localVs = localServer.String()
+	}
+	localMinClusterVs := ""
+	if localMinCluster != nil {
+		localMinClusterVs = localMinCluster.String()
+	}
+
+	if err != nil {
+		lg.Warn(
+			"failed version compatibility check",
+			zap.String("local-member-id", localID.String()),
+			zap.String("local-member-cluster-id", cid.String()),
+			zap.String("local-member-server-version", localVs),
+			zap.String("local-member-server-minimum-cluster-version", localMinClusterVs),
+			zap.String("remote-peer-server-name", remoteName),
+			zap.String("remote-peer-server-version", remoteVs),
+			zap.String("remote-peer-server-minimum-cluster-version", remoteMinClusterVs),
+			zap.Error(err),
+		)
+		return errIncompatibleVersion
+	}
+	if gcid := header.Get("X-Etcd-Cluster-ID"); gcid != cid.String() {
+		lg.Warn(
+			"request cluster ID mismatch",
+			zap.String("local-member-id", localID.String()),
+			zap.String("local-member-cluster-id", cid.String()),
+			zap.String("local-member-server-version", localVs),
+			zap.String("local-member-server-minimum-cluster-version", localMinClusterVs),
+			zap.String("remote-peer-server-name", remoteName),
+			zap.String("remote-peer-server-version", remoteVs),
+			zap.String("remote-peer-server-minimum-cluster-version", remoteMinClusterVs),
+			zap.String("remote-peer-cluster-id", gcid),
+		)
+		return ErrClusterIDMismatch
+	}
+	return nil
+}
+
+type closeNotifier struct {
+	done chan struct{}
+}
+
+func newCloseNotifier() *closeNotifier {
+	return &closeNotifier{
+		done: make(chan struct{}),
+	}
+}
+
+func (n *closeNotifier) Close() error {
+	close(n.done)
+	return nil
+}
+
+func (n *closeNotifier) closeNotify() <-chan struct{} { return n.done }
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/metrics.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/metrics.go
new file mode 100644
index 0000000..f9e13e2
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/metrics.go
@@ -0,0 +1,201 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package rafthttp
+
+import "github.com/prometheus/client_golang/prometheus"
+
+var (
+	activePeers = prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Namespace: "etcd",
+			Subsystem: "network",
+			Name:      "active_peers",
+			Help:      "The current number of active peer connections.",
+		},
+		[]string{"Local", "Remote"},
+	)
+
+	disconnectedPeers = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: "etcd",
+			Subsystem: "network",
+			Name:      "disconnected_peers_total",
+			Help:      "The total number of disconnected peers.",
+		},
+		[]string{"Local", "Remote"},
+	)
+
+	sentBytes = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: "etcd",
+			Subsystem: "network",
+			Name:      "peer_sent_bytes_total",
+			Help:      "The total number of bytes sent to peers.",
+		},
+		[]string{"To"},
+	)
+
+	receivedBytes = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: "etcd",
+			Subsystem: "network",
+			Name:      "peer_received_bytes_total",
+			Help:      "The total number of bytes received from peers.",
+		},
+		[]string{"From"},
+	)
+
+	sentFailures = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: "etcd",
+			Subsystem: "network",
+			Name:      "peer_sent_failures_total",
+			Help:      "The total number of send failures from peers.",
+		},
+		[]string{"To"},
+	)
+
+	recvFailures = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: "etcd",
+			Subsystem: "network",
+			Name:      "peer_received_failures_total",
+			Help:      "The total number of receive failures from peers.",
+		},
+		[]string{"From"},
+	)
+
+	snapshotSend = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: "etcd",
+			Subsystem: "network",
+			Name:      "snapshot_send_success",
+			Help:      "Total number of successful snapshot sends",
+		},
+		[]string{"To"},
+	)
+
+	snapshotSendInflights = prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Namespace: "etcd",
+			Subsystem: "network",
+			Name:      "snapshot_send_inflights_total",
+			Help:      "Total number of inflight snapshot sends",
+		},
+		[]string{"To"},
+	)
+
+	snapshotSendFailures = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: "etcd",
+			Subsystem: "network",
+			Name:      "snapshot_send_failures",
+			Help:      "Total number of snapshot send failures",
+		},
+		[]string{"To"},
+	)
+
+	snapshotSendSeconds = prometheus.NewHistogramVec(
+		prometheus.HistogramOpts{
+			Namespace: "etcd",
+			Subsystem: "network",
+			Name:      "snapshot_send_total_duration_seconds",
+			Help:      "Total latency distributions of v3 snapshot sends",
+
+			// lowest bucket start of upper bound 0.1 sec (100 ms) with factor 2
+			// highest bucket start of 0.1 sec * 2^9 == 51.2 sec
+			Buckets: prometheus.ExponentialBuckets(0.1, 2, 10),
+		},
+		[]string{"To"},
+	)
+
+	snapshotReceive = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: "etcd",
+			Subsystem: "network",
+			Name:      "snapshot_receive_success",
+			Help:      "Total number of successful snapshot receives",
+		},
+		[]string{"From"},
+	)
+
+	snapshotReceiveInflights = prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Namespace: "etcd",
+			Subsystem: "network",
+			Name:      "snapshot_receive_inflights_total",
+			Help:      "Total number of inflight snapshot receives",
+		},
+		[]string{"From"},
+	)
+
+	snapshotReceiveFailures = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: "etcd",
+			Subsystem: "network",
+			Name:      "snapshot_receive_failures",
+			Help:      "Total number of snapshot receive failures",
+		},
+		[]string{"From"},
+	)
+
+	snapshotReceiveSeconds = prometheus.NewHistogramVec(
+		prometheus.HistogramOpts{
+			Namespace: "etcd",
+			Subsystem: "network",
+			Name:      "snapshot_receive_total_duration_seconds",
+			Help:      "Total latency distributions of v3 snapshot receives",
+
+			// lowest bucket start of upper bound 0.1 sec (100 ms) with factor 2
+			// highest bucket start of 0.1 sec * 2^9 == 51.2 sec
+			Buckets: prometheus.ExponentialBuckets(0.1, 2, 10),
+		},
+		[]string{"From"},
+	)
+
+	rttSec = prometheus.NewHistogramVec(
+		prometheus.HistogramOpts{
+			Namespace: "etcd",
+			Subsystem: "network",
+			Name:      "peer_round_trip_time_seconds",
+			Help:      "Round-Trip-Time histogram between peers",
+
+			// lowest bucket start of upper bound 0.0001 sec (0.1 ms) with factor 2
+			// highest bucket start of 0.0001 sec * 2^15 == 3.2768 sec
+			Buckets: prometheus.ExponentialBuckets(0.0001, 2, 16),
+		},
+		[]string{"To"},
+	)
+)
+
+func init() {
+	prometheus.MustRegister(activePeers)
+	prometheus.MustRegister(disconnectedPeers)
+	prometheus.MustRegister(sentBytes)
+	prometheus.MustRegister(receivedBytes)
+	prometheus.MustRegister(sentFailures)
+	prometheus.MustRegister(recvFailures)
+
+	prometheus.MustRegister(snapshotSend)
+	prometheus.MustRegister(snapshotSendInflights)
+	prometheus.MustRegister(snapshotSendFailures)
+	prometheus.MustRegister(snapshotSendSeconds)
+	prometheus.MustRegister(snapshotReceive)
+	prometheus.MustRegister(snapshotReceiveInflights)
+	prometheus.MustRegister(snapshotReceiveFailures)
+	prometheus.MustRegister(snapshotReceiveSeconds)
+
+	prometheus.MustRegister(rttSec)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/msg_codec.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/msg_codec.go
new file mode 100644
index 0000000..5444c01
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/msg_codec.go
@@ -0,0 +1,68 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package rafthttp
+
+import (
+	"encoding/binary"
+	"errors"
+	"io"
+
+	"go.etcd.io/etcd/pkg/v3/pbutil"
+	"go.etcd.io/raft/v3/raftpb"
+)
+
+// messageEncoder is a encoder that can encode all kinds of messages.
+// It MUST be used with a paired messageDecoder.
+type messageEncoder struct {
+	w io.Writer
+}
+
+func (enc *messageEncoder) encode(m *raftpb.Message) error {
+	if err := binary.Write(enc.w, binary.BigEndian, uint64(m.Size())); err != nil {
+		return err
+	}
+	_, err := enc.w.Write(pbutil.MustMarshal(m))
+	return err
+}
+
+// messageDecoder is a decoder that can decode all kinds of messages.
+type messageDecoder struct {
+	r io.Reader
+}
+
+var (
+	readBytesLimit     uint64 = 512 * 1024 * 1024 // 512 MB
+	ErrExceedSizeLimit        = errors.New("rafthttp: error limit exceeded")
+)
+
+func (dec *messageDecoder) decode() (raftpb.Message, error) {
+	return dec.decodeLimit(readBytesLimit)
+}
+
+func (dec *messageDecoder) decodeLimit(numBytes uint64) (raftpb.Message, error) {
+	var m raftpb.Message
+	var l uint64
+	if err := binary.Read(dec.r, binary.BigEndian, &l); err != nil {
+		return m, err
+	}
+	if l > numBytes {
+		return m, ErrExceedSizeLimit
+	}
+	buf := make([]byte, int(l))
+	if _, err := io.ReadFull(dec.r, buf); err != nil {
+		return m, err
+	}
+	return m, m.Unmarshal(buf)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/msgappv2_codec.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/msgappv2_codec.go
new file mode 100644
index 0000000..59425ae
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/msgappv2_codec.go
@@ -0,0 +1,248 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package rafthttp
+
+import (
+	"encoding/binary"
+	"fmt"
+	"io"
+	"time"
+
+	"go.etcd.io/etcd/client/pkg/v3/types"
+	"go.etcd.io/etcd/pkg/v3/pbutil"
+	stats "go.etcd.io/etcd/server/v3/etcdserver/api/v2stats"
+	"go.etcd.io/raft/v3/raftpb"
+)
+
+const (
+	msgTypeLinkHeartbeat uint8 = 0
+	msgTypeAppEntries    uint8 = 1
+	msgTypeApp           uint8 = 2
+
+	msgAppV2BufSize = 1024 * 1024
+)
+
+// msgappv2 stream sends three types of message: linkHeartbeatMessage,
+// AppEntries and MsgApp. AppEntries is the MsgApp that is sent in
+// replicate state in raft, whose index and term are fully predictable.
+//
+// Data format of linkHeartbeatMessage:
+// | offset | bytes | description |
+// +--------+-------+-------------+
+// | 0      | 1     | \x00        |
+//
+// Data format of AppEntries:
+// | offset | bytes | description |
+// +--------+-------+-------------+
+// | 0      | 1     | \x01        |
+// | 1      | 8     | length of entries |
+// | 9      | 8     | length of first entry |
+// | 17     | n1    | first entry |
+// ...
+// | x      | 8     | length of k-th entry data |
+// | x+8    | nk    | k-th entry data |
+// | x+8+nk | 8     | commit index |
+//
+// Data format of MsgApp:
+// | offset | bytes | description |
+// +--------+-------+-------------+
+// | 0      | 1     | \x02        |
+// | 1      | 8     | length of encoded message |
+// | 9      | n     | encoded message |
+type msgAppV2Encoder struct {
+	w  io.Writer
+	fs *stats.FollowerStats
+
+	term      uint64
+	index     uint64
+	buf       []byte
+	uint64buf []byte
+	uint8buf  []byte
+}
+
+func newMsgAppV2Encoder(w io.Writer, fs *stats.FollowerStats) *msgAppV2Encoder {
+	return &msgAppV2Encoder{
+		w:         w,
+		fs:        fs,
+		buf:       make([]byte, msgAppV2BufSize),
+		uint64buf: make([]byte, 8),
+		uint8buf:  make([]byte, 1),
+	}
+}
+
+func (enc *msgAppV2Encoder) encode(m *raftpb.Message) error {
+	start := time.Now()
+	switch {
+	case isLinkHeartbeatMessage(m):
+		enc.uint8buf[0] = msgTypeLinkHeartbeat
+		if _, err := enc.w.Write(enc.uint8buf); err != nil {
+			return err
+		}
+	case enc.index == m.Index && enc.term == m.LogTerm && m.LogTerm == m.Term:
+		enc.uint8buf[0] = msgTypeAppEntries
+		if _, err := enc.w.Write(enc.uint8buf); err != nil {
+			return err
+		}
+		// write length of entries
+		binary.BigEndian.PutUint64(enc.uint64buf, uint64(len(m.Entries)))
+		if _, err := enc.w.Write(enc.uint64buf); err != nil {
+			return err
+		}
+		for i := 0; i < len(m.Entries); i++ {
+			// write length of entry
+			binary.BigEndian.PutUint64(enc.uint64buf, uint64(m.Entries[i].Size()))
+			if _, err := enc.w.Write(enc.uint64buf); err != nil {
+				return err
+			}
+			if n := m.Entries[i].Size(); n < msgAppV2BufSize {
+				if _, err := m.Entries[i].MarshalTo(enc.buf); err != nil {
+					return err
+				}
+				if _, err := enc.w.Write(enc.buf[:n]); err != nil {
+					return err
+				}
+			} else {
+				if _, err := enc.w.Write(pbutil.MustMarshal(&m.Entries[i])); err != nil {
+					return err
+				}
+			}
+			enc.index++
+		}
+		// write commit index
+		binary.BigEndian.PutUint64(enc.uint64buf, m.Commit)
+		if _, err := enc.w.Write(enc.uint64buf); err != nil {
+			return err
+		}
+		enc.fs.Succ(time.Since(start))
+	default:
+		if err := binary.Write(enc.w, binary.BigEndian, msgTypeApp); err != nil {
+			return err
+		}
+		// write size of message
+		if err := binary.Write(enc.w, binary.BigEndian, uint64(m.Size())); err != nil {
+			return err
+		}
+		// write message
+		if _, err := enc.w.Write(pbutil.MustMarshal(m)); err != nil {
+			return err
+		}
+
+		enc.term = m.Term
+		enc.index = m.Index
+		if l := len(m.Entries); l > 0 {
+			enc.index = m.Entries[l-1].Index
+		}
+		enc.fs.Succ(time.Since(start))
+	}
+	return nil
+}
+
+type msgAppV2Decoder struct {
+	r             io.Reader
+	local, remote types.ID
+
+	term      uint64
+	index     uint64
+	buf       []byte
+	uint64buf []byte
+	uint8buf  []byte
+}
+
+func newMsgAppV2Decoder(r io.Reader, local, remote types.ID) *msgAppV2Decoder {
+	return &msgAppV2Decoder{
+		r:         r,
+		local:     local,
+		remote:    remote,
+		buf:       make([]byte, msgAppV2BufSize),
+		uint64buf: make([]byte, 8),
+		uint8buf:  make([]byte, 1),
+	}
+}
+
+func (dec *msgAppV2Decoder) decode() (raftpb.Message, error) {
+	var (
+		m   raftpb.Message
+		typ uint8
+	)
+	if _, err := io.ReadFull(dec.r, dec.uint8buf); err != nil {
+		return m, err
+	}
+	typ = dec.uint8buf[0]
+	switch typ {
+	case msgTypeLinkHeartbeat:
+		return linkHeartbeatMessage, nil
+	case msgTypeAppEntries:
+		m = raftpb.Message{
+			Type:    raftpb.MsgApp,
+			From:    uint64(dec.remote),
+			To:      uint64(dec.local),
+			Term:    dec.term,
+			LogTerm: dec.term,
+			Index:   dec.index,
+		}
+
+		// decode entries
+		if _, err := io.ReadFull(dec.r, dec.uint64buf); err != nil {
+			return m, err
+		}
+		l := binary.BigEndian.Uint64(dec.uint64buf)
+		m.Entries = make([]raftpb.Entry, int(l))
+		for i := 0; i < int(l); i++ {
+			if _, err := io.ReadFull(dec.r, dec.uint64buf); err != nil {
+				return m, err
+			}
+			size := binary.BigEndian.Uint64(dec.uint64buf)
+			var buf []byte
+			if size < msgAppV2BufSize {
+				buf = dec.buf[:size]
+				if _, err := io.ReadFull(dec.r, buf); err != nil {
+					return m, err
+				}
+			} else {
+				buf = make([]byte, int(size))
+				if _, err := io.ReadFull(dec.r, buf); err != nil {
+					return m, err
+				}
+			}
+			dec.index++
+			// 1 alloc
+			pbutil.MustUnmarshal(&m.Entries[i], buf)
+		}
+		// decode commit index
+		if _, err := io.ReadFull(dec.r, dec.uint64buf); err != nil {
+			return m, err
+		}
+		m.Commit = binary.BigEndian.Uint64(dec.uint64buf)
+	case msgTypeApp:
+		var size uint64
+		if err := binary.Read(dec.r, binary.BigEndian, &size); err != nil {
+			return m, err
+		}
+		buf := make([]byte, int(size))
+		if _, err := io.ReadFull(dec.r, buf); err != nil {
+			return m, err
+		}
+		pbutil.MustUnmarshal(&m, buf)
+
+		dec.term = m.Term
+		dec.index = m.Index
+		if l := len(m.Entries); l > 0 {
+			dec.index = m.Entries[l-1].Index
+		}
+	default:
+		return m, fmt.Errorf("failed to parse type %d in msgappv2 stream", typ)
+	}
+	return m, nil
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/peer.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/peer.go
new file mode 100644
index 0000000..c1e6ba1
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/peer.go
@@ -0,0 +1,353 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package rafthttp
+
+import (
+	"context"
+	"sync"
+	"time"
+
+	"go.uber.org/zap"
+	"golang.org/x/time/rate"
+
+	"go.etcd.io/etcd/client/pkg/v3/types"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/snap"
+	stats "go.etcd.io/etcd/server/v3/etcdserver/api/v2stats"
+	"go.etcd.io/raft/v3"
+	"go.etcd.io/raft/v3/raftpb"
+)
+
+const (
+	// ConnReadTimeout and ConnWriteTimeout are the i/o timeout set on each connection rafthttp pkg creates.
+	// A 5 seconds timeout is good enough for recycling bad connections. Or we have to wait for
+	// tcp keepalive failing to detect a bad connection, which is at minutes level.
+	// For long term streaming connections, rafthttp pkg sends application level linkHeartbeatMessage
+	// to keep the connection alive.
+	// For short term pipeline connections, the connection MUST be killed to avoid it being
+	// put back to http pkg connection pool.
+	DefaultConnReadTimeout  = 5 * time.Second
+	DefaultConnWriteTimeout = 5 * time.Second
+
+	recvBufSize = 4096
+	// maxPendingProposals holds the proposals during one leader election process.
+	// Generally one leader election takes at most 1 sec. It should have
+	// 0-2 election conflicts, and each one takes 0.5 sec.
+	// We assume the number of concurrent proposers is smaller than 4096.
+	// One client blocks on its proposal for at least 1 sec, so 4096 is enough
+	// to hold all proposals.
+	maxPendingProposals = 4096
+
+	streamAppV2 = "streamMsgAppV2"
+	streamMsg   = "streamMsg"
+	pipelineMsg = "pipeline"
+	sendSnap    = "sendMsgSnap"
+)
+
+var (
+	ConnReadTimeout  = DefaultConnReadTimeout
+	ConnWriteTimeout = DefaultConnWriteTimeout
+)
+
+type Peer interface {
+	// send sends the message to the remote peer. The function is non-blocking
+	// and has no promise that the message will be received by the remote.
+	// When it fails to send message out, it will report the status to underlying
+	// raft.
+	send(m raftpb.Message)
+
+	// sendSnap sends the merged snapshot message to the remote peer. Its behavior
+	// is similar to send.
+	sendSnap(m snap.Message)
+
+	// update updates the urls of remote peer.
+	update(urls types.URLs)
+
+	// attachOutgoingConn attaches the outgoing connection to the peer for
+	// stream usage. After the call, the ownership of the outgoing
+	// connection hands over to the peer. The peer will close the connection
+	// when it is no longer used.
+	attachOutgoingConn(conn *outgoingConn)
+	// activeSince returns the time that the connection with the
+	// peer becomes active.
+	activeSince() time.Time
+	// stop performs any necessary finalization and terminates the peer
+	// elegantly.
+	stop()
+}
+
+// peer is the representative of a remote raft node. Local raft node sends
+// messages to the remote through peer.
+// Each peer has two underlying mechanisms to send out a message: stream and
+// pipeline.
+// A stream is a receiver initialized long-polling connection, which
+// is always open to transfer messages. Besides general stream, peer also has
+// a optimized stream for sending msgApp since msgApp accounts for large part
+// of all messages. Only raft leader uses the optimized stream to send msgApp
+// to the remote follower node.
+// A pipeline is a series of http clients that send http requests to the remote.
+// It is only used when the stream has not been established.
+type peer struct {
+	lg *zap.Logger
+
+	localID types.ID
+	// id of the remote raft peer node
+	id types.ID
+
+	r Raft
+
+	status *peerStatus
+
+	picker *urlPicker
+
+	msgAppV2Writer *streamWriter
+	writer         *streamWriter
+	pipeline       *pipeline
+	snapSender     *snapshotSender // snapshot sender to send v3 snapshot messages
+	msgAppV2Reader *streamReader
+	msgAppReader   *streamReader
+
+	recvc chan raftpb.Message
+	propc chan raftpb.Message
+
+	mu     sync.Mutex
+	paused bool
+
+	cancel context.CancelFunc // cancel pending works in go routine created by peer.
+	stopc  chan struct{}
+}
+
+func startPeer(t *Transport, urls types.URLs, peerID types.ID, fs *stats.FollowerStats) *peer {
+	if t.Logger != nil {
+		t.Logger.Info("starting remote peer", zap.String("remote-peer-id", peerID.String()))
+	}
+	defer func() {
+		if t.Logger != nil {
+			t.Logger.Info("started remote peer", zap.String("remote-peer-id", peerID.String()))
+		}
+	}()
+
+	status := newPeerStatus(t.Logger, t.ID, peerID)
+	picker := newURLPicker(urls)
+	errorc := t.ErrorC
+	r := t.Raft
+	pipeline := &pipeline{
+		peerID:        peerID,
+		tr:            t,
+		picker:        picker,
+		status:        status,
+		followerStats: fs,
+		raft:          r,
+		errorc:        errorc,
+	}
+	pipeline.start()
+
+	p := &peer{
+		lg:             t.Logger,
+		localID:        t.ID,
+		id:             peerID,
+		r:              r,
+		status:         status,
+		picker:         picker,
+		msgAppV2Writer: startStreamWriter(t.Logger, t.ID, peerID, status, fs, r),
+		writer:         startStreamWriter(t.Logger, t.ID, peerID, status, fs, r),
+		pipeline:       pipeline,
+		snapSender:     newSnapshotSender(t, picker, peerID, status),
+		recvc:          make(chan raftpb.Message, recvBufSize),
+		propc:          make(chan raftpb.Message, maxPendingProposals),
+		stopc:          make(chan struct{}),
+	}
+
+	ctx, cancel := context.WithCancel(context.Background())
+	p.cancel = cancel
+	go func() {
+		for {
+			select {
+			case mm := <-p.recvc:
+				if err := r.Process(ctx, mm); err != nil {
+					if t.Logger != nil {
+						t.Logger.Warn("failed to process Raft message", zap.Error(err))
+					}
+				}
+			case <-p.stopc:
+				return
+			}
+		}
+	}()
+
+	// r.Process might block for processing proposal when there is no leader.
+	// Thus propc must be put into a separate routine with recvc to avoid blocking
+	// processing other raft messages.
+	go func() {
+		for {
+			select {
+			case mm := <-p.propc:
+				if err := r.Process(ctx, mm); err != nil {
+					if t.Logger != nil {
+						t.Logger.Warn("failed to process Raft message", zap.Error(err))
+					}
+				}
+			case <-p.stopc:
+				return
+			}
+		}
+	}()
+
+	p.msgAppV2Reader = &streamReader{
+		lg:     t.Logger,
+		peerID: peerID,
+		typ:    streamTypeMsgAppV2,
+		tr:     t,
+		picker: picker,
+		status: status,
+		recvc:  p.recvc,
+		propc:  p.propc,
+		rl:     rate.NewLimiter(t.DialRetryFrequency, 1),
+	}
+	p.msgAppReader = &streamReader{
+		lg:     t.Logger,
+		peerID: peerID,
+		typ:    streamTypeMessage,
+		tr:     t,
+		picker: picker,
+		status: status,
+		recvc:  p.recvc,
+		propc:  p.propc,
+		rl:     rate.NewLimiter(t.DialRetryFrequency, 1),
+	}
+
+	p.msgAppV2Reader.start()
+	p.msgAppReader.start()
+
+	return p
+}
+
+func (p *peer) send(m raftpb.Message) {
+	p.mu.Lock()
+	paused := p.paused
+	p.mu.Unlock()
+
+	if paused {
+		return
+	}
+
+	writec, name := p.pick(m)
+	select {
+	case writec <- m:
+	default:
+		p.r.ReportUnreachable(m.To)
+		if isMsgSnap(m) {
+			p.r.ReportSnapshot(m.To, raft.SnapshotFailure)
+		}
+		if p.lg != nil {
+			p.lg.Warn(
+				"dropped internal Raft message since sending buffer is full",
+				zap.String("message-type", m.Type.String()),
+				zap.String("local-member-id", p.localID.String()),
+				zap.String("from", types.ID(m.From).String()),
+				zap.String("remote-peer-id", p.id.String()),
+				zap.String("remote-peer-name", name),
+				zap.Bool("remote-peer-active", p.status.isActive()),
+			)
+		}
+		sentFailures.WithLabelValues(types.ID(m.To).String()).Inc()
+	}
+}
+
+func (p *peer) sendSnap(m snap.Message) {
+	go p.snapSender.send(m)
+}
+
+func (p *peer) update(urls types.URLs) {
+	p.picker.update(urls)
+}
+
+func (p *peer) attachOutgoingConn(conn *outgoingConn) {
+	var ok bool
+	switch conn.t {
+	case streamTypeMsgAppV2:
+		ok = p.msgAppV2Writer.attach(conn)
+	case streamTypeMessage:
+		ok = p.writer.attach(conn)
+	default:
+		if p.lg != nil {
+			p.lg.Panic("unknown stream type", zap.String("type", conn.t.String()))
+		}
+	}
+	if !ok {
+		conn.Close()
+	}
+}
+
+func (p *peer) activeSince() time.Time { return p.status.activeSince() }
+
+// Pause pauses the peer. The peer will simply drops all incoming
+// messages without returning an error.
+func (p *peer) Pause() {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	p.paused = true
+	p.msgAppReader.pause()
+	p.msgAppV2Reader.pause()
+}
+
+// Resume resumes a paused peer.
+func (p *peer) Resume() {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	p.paused = false
+	p.msgAppReader.resume()
+	p.msgAppV2Reader.resume()
+}
+
+func (p *peer) stop() {
+	if p.lg != nil {
+		p.lg.Info("stopping remote peer", zap.String("remote-peer-id", p.id.String()))
+	}
+
+	defer func() {
+		if p.lg != nil {
+			p.lg.Info("stopped remote peer", zap.String("remote-peer-id", p.id.String()))
+		}
+	}()
+
+	close(p.stopc)
+	p.cancel()
+	p.msgAppV2Writer.stop()
+	p.writer.stop()
+	p.pipeline.stop()
+	p.snapSender.stop()
+	p.msgAppV2Reader.stop()
+	p.msgAppReader.stop()
+}
+
+// pick picks a chan for sending the given message. The picked chan and the picked chan
+// string name are returned.
+func (p *peer) pick(m raftpb.Message) (writec chan<- raftpb.Message, picked string) {
+	var ok bool
+	// Considering MsgSnap may have a big size, e.g., 1G, and will block
+	// stream for a long time, only use one of the N pipelines to send MsgSnap.
+	if isMsgSnap(m) {
+		return p.pipeline.msgc, pipelineMsg
+	} else if writec, ok = p.msgAppV2Writer.writec(); ok && isMsgApp(m) {
+		return writec, streamAppV2
+	} else if writec, ok = p.writer.writec(); ok {
+		return writec, streamMsg
+	}
+	return p.pipeline.msgc, pipelineMsg
+}
+
+func isMsgApp(m raftpb.Message) bool { return m.Type == raftpb.MsgApp }
+
+func isMsgSnap(m raftpb.Message) bool { return m.Type == raftpb.MsgSnap }
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/peer_status.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/peer_status.go
new file mode 100644
index 0000000..01c3eba
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/peer_status.go
@@ -0,0 +1,90 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package rafthttp
+
+import (
+	"errors"
+	"fmt"
+	"sync"
+	"time"
+
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/client/pkg/v3/types"
+)
+
+type failureType struct {
+	source string
+	action string
+}
+
+type peerStatus struct {
+	lg     *zap.Logger
+	local  types.ID
+	id     types.ID
+	mu     sync.Mutex // protect variables below
+	active bool
+	since  time.Time
+}
+
+func newPeerStatus(lg *zap.Logger, local, id types.ID) *peerStatus {
+	if lg == nil {
+		lg = zap.NewNop()
+	}
+	return &peerStatus{lg: lg, local: local, id: id}
+}
+
+func (s *peerStatus) activate() {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if !s.active {
+		s.lg.Info("peer became active", zap.String("peer-id", s.id.String()))
+		s.active = true
+		s.since = time.Now()
+
+		activePeers.WithLabelValues(s.local.String(), s.id.String()).Inc()
+	}
+}
+
+func (s *peerStatus) deactivate(failure failureType, reason string) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	msg := fmt.Sprintf("failed to %s %s on %s (%s)", failure.action, s.id, failure.source, reason)
+	if s.active {
+		s.lg.Warn("peer became inactive (message send to peer failed)", zap.String("peer-id", s.id.String()), zap.Error(errors.New(msg)))
+		s.active = false
+		s.since = time.Time{}
+
+		activePeers.WithLabelValues(s.local.String(), s.id.String()).Dec()
+		disconnectedPeers.WithLabelValues(s.local.String(), s.id.String()).Inc()
+		return
+	}
+
+	if s.lg != nil {
+		s.lg.Debug("peer deactivated again", zap.String("peer-id", s.id.String()), zap.Error(errors.New(msg)))
+	}
+}
+
+func (s *peerStatus) isActive() bool {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.active
+}
+
+func (s *peerStatus) activeSince() time.Time {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.since
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/pipeline.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/pipeline.go
new file mode 100644
index 0000000..0790b58
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/pipeline.go
@@ -0,0 +1,178 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package rafthttp
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"io"
+	"runtime"
+	"sync"
+	"time"
+
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/client/pkg/v3/types"
+	"go.etcd.io/etcd/pkg/v3/pbutil"
+	stats "go.etcd.io/etcd/server/v3/etcdserver/api/v2stats"
+	"go.etcd.io/raft/v3"
+	"go.etcd.io/raft/v3/raftpb"
+)
+
+const (
+	connPerPipeline = 4
+	// pipelineBufSize is the size of pipeline buffer, which helps hold the
+	// temporary network latency.
+	// The size ensures that pipeline does not drop messages when the network
+	// is out of work for less than 1 second in good path.
+	pipelineBufSize = 64
+)
+
+var errStopped = errors.New("stopped")
+
+type pipeline struct {
+	peerID types.ID
+
+	tr     *Transport
+	picker *urlPicker
+	status *peerStatus
+	raft   Raft
+	errorc chan error
+	// deprecate when we depercate v2 API
+	followerStats *stats.FollowerStats
+
+	msgc chan raftpb.Message
+	// wait for the handling routines
+	wg    sync.WaitGroup
+	stopc chan struct{}
+}
+
+func (p *pipeline) start() {
+	p.stopc = make(chan struct{})
+	p.msgc = make(chan raftpb.Message, pipelineBufSize)
+	p.wg.Add(connPerPipeline)
+	for i := 0; i < connPerPipeline; i++ {
+		go p.handle()
+	}
+
+	if p.tr != nil && p.tr.Logger != nil {
+		p.tr.Logger.Info(
+			"started HTTP pipelining with remote peer",
+			zap.String("local-member-id", p.tr.ID.String()),
+			zap.String("remote-peer-id", p.peerID.String()),
+		)
+	}
+}
+
+func (p *pipeline) stop() {
+	close(p.stopc)
+	p.wg.Wait()
+
+	if p.tr != nil && p.tr.Logger != nil {
+		p.tr.Logger.Info(
+			"stopped HTTP pipelining with remote peer",
+			zap.String("local-member-id", p.tr.ID.String()),
+			zap.String("remote-peer-id", p.peerID.String()),
+		)
+	}
+}
+
+func (p *pipeline) handle() {
+	defer p.wg.Done()
+
+	for {
+		select {
+		case m := <-p.msgc:
+			start := time.Now()
+			err := p.post(pbutil.MustMarshal(&m))
+			end := time.Now()
+
+			if err != nil {
+				p.status.deactivate(failureType{source: pipelineMsg, action: "write"}, err.Error())
+
+				if isMsgApp(m) && p.followerStats != nil {
+					p.followerStats.Fail()
+				}
+				p.raft.ReportUnreachable(m.To)
+				if isMsgSnap(m) {
+					p.raft.ReportSnapshot(m.To, raft.SnapshotFailure)
+				}
+				sentFailures.WithLabelValues(types.ID(m.To).String()).Inc()
+				continue
+			}
+
+			p.status.activate()
+			if isMsgApp(m) && p.followerStats != nil {
+				p.followerStats.Succ(end.Sub(start))
+			}
+			if isMsgSnap(m) {
+				p.raft.ReportSnapshot(m.To, raft.SnapshotFinish)
+			}
+			sentBytes.WithLabelValues(types.ID(m.To).String()).Add(float64(m.Size()))
+		case <-p.stopc:
+			return
+		}
+	}
+}
+
+// post POSTs a data payload to a url. Returns nil if the POST succeeds,
+// error on any failure.
+func (p *pipeline) post(data []byte) (err error) {
+	u := p.picker.pick()
+	req := createPostRequest(p.tr.Logger, u, RaftPrefix, bytes.NewBuffer(data), "application/protobuf", p.tr.URLs, p.tr.ID, p.tr.ClusterID)
+
+	done := make(chan struct{}, 1)
+	ctx, cancel := context.WithCancel(context.Background())
+	req = req.WithContext(ctx)
+	go func() {
+		select {
+		case <-done:
+			cancel()
+		case <-p.stopc:
+			waitSchedule()
+			cancel()
+		}
+	}()
+
+	resp, err := p.tr.pipelineRt.RoundTrip(req)
+	done <- struct{}{}
+	if err != nil {
+		p.picker.unreachable(u)
+		return err
+	}
+	defer resp.Body.Close()
+	b, err := io.ReadAll(resp.Body)
+	if err != nil {
+		p.picker.unreachable(u)
+		return err
+	}
+
+	err = checkPostResponse(p.tr.Logger, resp, b, req, p.peerID)
+	if err != nil {
+		p.picker.unreachable(u)
+		// errMemberRemoved is a critical error since a removed member should
+		// always be stopped. So we use reportCriticalError to report it to errorc.
+		if errors.Is(err, errMemberRemoved) {
+			reportCriticalError(err, p.errorc)
+		}
+		return err
+	}
+
+	return nil
+}
+
+// waitSchedule waits other goroutines to be scheduled for a while
+func waitSchedule() { runtime.Gosched() }
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/probing_status.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/probing_status.go
new file mode 100644
index 0000000..672a579
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/probing_status.go
@@ -0,0 +1,98 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package rafthttp
+
+import (
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/xiang90/probing"
+	"go.uber.org/zap"
+)
+
+const (
+	// RoundTripperNameRaftMessage is the name of round-tripper that sends
+	// all other Raft messages, other than "snap.Message".
+	RoundTripperNameRaftMessage = "ROUND_TRIPPER_RAFT_MESSAGE"
+	// RoundTripperNameSnapshot is the name of round-tripper that sends merged snapshot message.
+	RoundTripperNameSnapshot = "ROUND_TRIPPER_SNAPSHOT"
+)
+
+var (
+	// proberInterval must be shorter than read timeout.
+	// Or the connection will time-out.
+	proberInterval           = ConnReadTimeout - time.Second
+	statusMonitoringInterval = 30 * time.Second
+	statusErrorInterval      = 5 * time.Second
+)
+
+func addPeerToProber(lg *zap.Logger, p probing.Prober, id string, us []string, roundTripperName string, rttSecProm *prometheus.HistogramVec) {
+	hus := make([]string, len(us))
+	for i := range us {
+		hus[i] = us[i] + ProbingPrefix
+	}
+
+	p.AddHTTP(id, proberInterval, hus)
+
+	s, err := p.Status(id)
+	if err != nil {
+		if lg != nil {
+			lg.Warn("failed to add peer into prober", zap.String("remote-peer-id", id), zap.Error(err))
+		}
+		return
+	}
+
+	go monitorProbingStatus(lg, s, id, roundTripperName, rttSecProm)
+}
+
+func monitorProbingStatus(lg *zap.Logger, s probing.Status, id string, roundTripperName string, rttSecProm *prometheus.HistogramVec) {
+	// set the first interval short to log error early.
+	interval := statusErrorInterval
+	for {
+		select {
+		case <-time.After(interval):
+			if !s.Health() {
+				if lg != nil {
+					lg.Warn(
+						"prober detected unhealthy status",
+						zap.String("round-tripper-name", roundTripperName),
+						zap.String("remote-peer-id", id),
+						zap.Duration("rtt", s.SRTT()),
+						zap.Error(s.Err()),
+					)
+				}
+				interval = statusErrorInterval
+			} else {
+				interval = statusMonitoringInterval
+			}
+			if s.ClockDiff() > time.Second {
+				if lg != nil {
+					lg.Warn(
+						"prober found high clock drift",
+						zap.String("round-tripper-name", roundTripperName),
+						zap.String("remote-peer-id", id),
+						zap.Duration("clock-drift", s.ClockDiff()),
+						zap.Duration("rtt", s.SRTT()),
+						zap.Error(s.Err()),
+					)
+				}
+			}
+			rttSecProm.WithLabelValues(id).Observe(s.SRTT().Seconds())
+
+		case <-s.StopNotify():
+			return
+		}
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/remote.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/remote.go
new file mode 100644
index 0000000..3eb2f38
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/remote.go
@@ -0,0 +1,95 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package rafthttp
+
+import (
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/client/pkg/v3/types"
+	"go.etcd.io/raft/v3/raftpb"
+)
+
+type remote struct {
+	lg       *zap.Logger
+	localID  types.ID
+	id       types.ID
+	status   *peerStatus
+	pipeline *pipeline
+}
+
+func startRemote(tr *Transport, urls types.URLs, id types.ID) *remote {
+	picker := newURLPicker(urls)
+	status := newPeerStatus(tr.Logger, tr.ID, id)
+	pipeline := &pipeline{
+		peerID: id,
+		tr:     tr,
+		picker: picker,
+		status: status,
+		raft:   tr.Raft,
+		errorc: tr.ErrorC,
+	}
+	pipeline.start()
+
+	return &remote{
+		lg:       tr.Logger,
+		localID:  tr.ID,
+		id:       id,
+		status:   status,
+		pipeline: pipeline,
+	}
+}
+
+func (g *remote) send(m raftpb.Message) {
+	select {
+	case g.pipeline.msgc <- m:
+	default:
+		if g.status.isActive() {
+			if g.lg != nil {
+				g.lg.Warn(
+					"dropped internal Raft message since sending buffer is full (overloaded network)",
+					zap.String("message-type", m.Type.String()),
+					zap.String("local-member-id", g.localID.String()),
+					zap.String("from", types.ID(m.From).String()),
+					zap.String("remote-peer-id", g.id.String()),
+					zap.Bool("remote-peer-active", g.status.isActive()),
+				)
+			}
+		} else {
+			if g.lg != nil {
+				g.lg.Warn(
+					"dropped Raft message since sending buffer is full (overloaded network)",
+					zap.String("message-type", m.Type.String()),
+					zap.String("local-member-id", g.localID.String()),
+					zap.String("from", types.ID(m.From).String()),
+					zap.String("remote-peer-id", g.id.String()),
+					zap.Bool("remote-peer-active", g.status.isActive()),
+				)
+			}
+		}
+		sentFailures.WithLabelValues(types.ID(m.To).String()).Inc()
+	}
+}
+
+func (g *remote) stop() {
+	g.pipeline.stop()
+}
+
+func (g *remote) Pause() {
+	g.stop()
+}
+
+func (g *remote) Resume() {
+	g.pipeline.start()
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/snapshot_sender.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/snapshot_sender.go
new file mode 100644
index 0000000..8dbc117
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/snapshot_sender.go
@@ -0,0 +1,199 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package rafthttp
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"io"
+	"net/http"
+	"time"
+
+	"github.com/dustin/go-humanize"
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/client/pkg/v3/types"
+	"go.etcd.io/etcd/pkg/v3/httputil"
+	pioutil "go.etcd.io/etcd/pkg/v3/ioutil"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/snap"
+	"go.etcd.io/raft/v3"
+)
+
+// timeout for reading snapshot response body
+var snapResponseReadTimeout = 5 * time.Second
+
+type snapshotSender struct {
+	from, to types.ID
+	cid      types.ID
+
+	tr     *Transport
+	picker *urlPicker
+	status *peerStatus
+	r      Raft
+	errorc chan error
+
+	stopc chan struct{}
+}
+
+func newSnapshotSender(tr *Transport, picker *urlPicker, to types.ID, status *peerStatus) *snapshotSender {
+	return &snapshotSender{
+		from:   tr.ID,
+		to:     to,
+		cid:    tr.ClusterID,
+		tr:     tr,
+		picker: picker,
+		status: status,
+		r:      tr.Raft,
+		errorc: tr.ErrorC,
+		stopc:  make(chan struct{}),
+	}
+}
+
+func (s *snapshotSender) stop() { close(s.stopc) }
+
+func (s *snapshotSender) send(merged snap.Message) {
+	start := time.Now()
+
+	m := merged.Message
+	to := types.ID(m.To).String()
+
+	body := createSnapBody(s.tr.Logger, merged)
+	defer body.Close()
+
+	u := s.picker.pick()
+	req := createPostRequest(s.tr.Logger, u, RaftSnapshotPrefix, body, "application/octet-stream", s.tr.URLs, s.from, s.cid)
+
+	snapshotSizeVal := uint64(merged.TotalSize)
+	snapshotSize := humanize.Bytes(snapshotSizeVal)
+	if s.tr.Logger != nil {
+		s.tr.Logger.Info(
+			"sending database snapshot",
+			zap.Uint64("snapshot-index", m.Snapshot.Metadata.Index),
+			zap.String("remote-peer-id", to),
+			zap.Uint64("bytes", snapshotSizeVal),
+			zap.String("size", snapshotSize),
+		)
+	}
+
+	snapshotSendInflights.WithLabelValues(to).Inc()
+	defer func() {
+		snapshotSendInflights.WithLabelValues(to).Dec()
+	}()
+
+	err := s.post(req)
+	defer merged.CloseWithError(err)
+	if err != nil {
+		if s.tr.Logger != nil {
+			s.tr.Logger.Warn(
+				"failed to send database snapshot",
+				zap.Uint64("snapshot-index", m.Snapshot.Metadata.Index),
+				zap.String("remote-peer-id", to),
+				zap.Uint64("bytes", snapshotSizeVal),
+				zap.String("size", snapshotSize),
+				zap.Error(err),
+			)
+		}
+
+		// errMemberRemoved is a critical error since a removed member should
+		// always be stopped. So we use reportCriticalError to report it to errorc.
+		if errors.Is(err, errMemberRemoved) {
+			reportCriticalError(err, s.errorc)
+		}
+
+		s.picker.unreachable(u)
+		s.status.deactivate(failureType{source: sendSnap, action: "post"}, err.Error())
+		s.r.ReportUnreachable(m.To)
+		// report SnapshotFailure to raft state machine. After raft state
+		// machine knows about it, it would pause a while and retry sending
+		// new snapshot message.
+		s.r.ReportSnapshot(m.To, raft.SnapshotFailure)
+		sentFailures.WithLabelValues(to).Inc()
+		snapshotSendFailures.WithLabelValues(to).Inc()
+		return
+	}
+	s.status.activate()
+	s.r.ReportSnapshot(m.To, raft.SnapshotFinish)
+
+	if s.tr.Logger != nil {
+		s.tr.Logger.Info(
+			"sent database snapshot",
+			zap.Uint64("snapshot-index", m.Snapshot.Metadata.Index),
+			zap.String("remote-peer-id", to),
+			zap.Uint64("bytes", snapshotSizeVal),
+			zap.String("size", snapshotSize),
+		)
+	}
+
+	sentBytes.WithLabelValues(to).Add(float64(merged.TotalSize))
+	snapshotSend.WithLabelValues(to).Inc()
+	snapshotSendSeconds.WithLabelValues(to).Observe(time.Since(start).Seconds())
+}
+
+// post posts the given request.
+// It returns nil when request is sent out and processed successfully.
+func (s *snapshotSender) post(req *http.Request) (err error) {
+	ctx, cancel := context.WithCancel(context.Background())
+	req = req.WithContext(ctx)
+	defer cancel()
+
+	type responseAndError struct {
+		resp *http.Response
+		body []byte
+		err  error
+	}
+	result := make(chan responseAndError, 1)
+
+	go func() {
+		resp, err := s.tr.pipelineRt.RoundTrip(req)
+		if err != nil {
+			result <- responseAndError{resp, nil, err}
+			return
+		}
+
+		// close the response body when timeouts.
+		// prevents from reading the body forever when the other side dies right after
+		// successfully receives the request body.
+		time.AfterFunc(snapResponseReadTimeout, func() { httputil.GracefulClose(resp) })
+		body, err := io.ReadAll(resp.Body)
+		result <- responseAndError{resp, body, err}
+	}()
+
+	select {
+	case <-s.stopc:
+		return errStopped
+	case r := <-result:
+		if r.err != nil {
+			return r.err
+		}
+		return checkPostResponse(s.tr.Logger, r.resp, r.body, req, s.to)
+	}
+}
+
+func createSnapBody(lg *zap.Logger, merged snap.Message) io.ReadCloser {
+	buf := new(bytes.Buffer)
+	enc := &messageEncoder{w: buf}
+	// encode raft message
+	if err := enc.encode(&merged.Message); err != nil {
+		if lg != nil {
+			lg.Panic("failed to encode message", zap.Error(err))
+		}
+	}
+
+	return &pioutil.ReaderAndCloser{
+		Reader: io.MultiReader(buf, merged.ReadCloser),
+		Closer: merged.ReadCloser,
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/stream.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/stream.go
new file mode 100644
index 0000000..fa02f42
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/stream.go
@@ -0,0 +1,712 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package rafthttp
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"path"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/coreos/go-semver/semver"
+	"go.uber.org/zap"
+	"golang.org/x/time/rate"
+
+	"go.etcd.io/etcd/api/v3/version"
+	"go.etcd.io/etcd/client/pkg/v3/transport"
+	"go.etcd.io/etcd/client/pkg/v3/types"
+	"go.etcd.io/etcd/pkg/v3/httputil"
+	stats "go.etcd.io/etcd/server/v3/etcdserver/api/v2stats"
+	"go.etcd.io/raft/v3/raftpb"
+)
+
+const (
+	streamTypeMessage  streamType = "message"
+	streamTypeMsgAppV2 streamType = "msgappv2"
+
+	streamBufSize = 4096
+)
+
+var (
+	errUnsupportedStreamType = fmt.Errorf("unsupported stream type")
+
+	// the key is in string format "major.minor.patch"
+	supportedStream = map[string][]streamType{
+		"2.0.0": {},
+		"2.1.0": {streamTypeMsgAppV2, streamTypeMessage},
+		"2.2.0": {streamTypeMsgAppV2, streamTypeMessage},
+		"2.3.0": {streamTypeMsgAppV2, streamTypeMessage},
+		"3.0.0": {streamTypeMsgAppV2, streamTypeMessage},
+		"3.1.0": {streamTypeMsgAppV2, streamTypeMessage},
+		"3.2.0": {streamTypeMsgAppV2, streamTypeMessage},
+		"3.3.0": {streamTypeMsgAppV2, streamTypeMessage},
+		"3.4.0": {streamTypeMsgAppV2, streamTypeMessage},
+		"3.5.0": {streamTypeMsgAppV2, streamTypeMessage},
+		"3.6.0": {streamTypeMsgAppV2, streamTypeMessage},
+	}
+)
+
+type streamType string
+
+func (t streamType) endpoint(lg *zap.Logger) string {
+	switch t {
+	case streamTypeMsgAppV2:
+		return path.Join(RaftStreamPrefix, "msgapp")
+	case streamTypeMessage:
+		return path.Join(RaftStreamPrefix, "message")
+	default:
+		if lg != nil {
+			lg.Panic("unhandled stream type", zap.String("stream-type", t.String()))
+		}
+		return ""
+	}
+}
+
+func (t streamType) String() string {
+	switch t {
+	case streamTypeMsgAppV2:
+		return "stream MsgApp v2"
+	case streamTypeMessage:
+		return "stream Message"
+	default:
+		return "unknown stream"
+	}
+}
+
+// linkHeartbeatMessage is a special message used as heartbeat message in
+// link layer. It never conflicts with messages from raft because raft
+// doesn't send out messages without From and To fields.
+var linkHeartbeatMessage = raftpb.Message{Type: raftpb.MsgHeartbeat}
+
+func isLinkHeartbeatMessage(m *raftpb.Message) bool {
+	return m.Type == raftpb.MsgHeartbeat && m.From == 0 && m.To == 0
+}
+
+type outgoingConn struct {
+	t streamType
+	io.Writer
+	http.Flusher
+	io.Closer
+
+	localID types.ID
+	peerID  types.ID
+}
+
+// streamWriter writes messages to the attached outgoingConn.
+type streamWriter struct {
+	lg *zap.Logger
+
+	localID types.ID
+	peerID  types.ID
+
+	status *peerStatus
+	fs     *stats.FollowerStats
+	r      Raft
+
+	mu      sync.Mutex // guard field working and closer
+	closer  io.Closer
+	working bool
+
+	msgc  chan raftpb.Message
+	connc chan *outgoingConn
+	stopc chan struct{}
+	done  chan struct{}
+}
+
+// startStreamWriter creates a streamWrite and starts a long running go-routine that accepts
+// messages and writes to the attached outgoing connection.
+func startStreamWriter(lg *zap.Logger, local, id types.ID, status *peerStatus, fs *stats.FollowerStats, r Raft) *streamWriter {
+	w := &streamWriter{
+		lg: lg,
+
+		localID: local,
+		peerID:  id,
+
+		status: status,
+		fs:     fs,
+		r:      r,
+		msgc:   make(chan raftpb.Message, streamBufSize),
+		connc:  make(chan *outgoingConn),
+		stopc:  make(chan struct{}),
+		done:   make(chan struct{}),
+	}
+	go w.run()
+	return w
+}
+
+func (cw *streamWriter) run() {
+	var (
+		msgc       chan raftpb.Message
+		heartbeatc <-chan time.Time
+		t          streamType
+		enc        encoder
+		flusher    http.Flusher
+		batched    int
+	)
+	tickc := time.NewTicker(ConnReadTimeout / 3)
+	defer tickc.Stop()
+	unflushed := 0
+
+	if cw.lg != nil {
+		cw.lg.Info(
+			"started stream writer with remote peer",
+			zap.String("local-member-id", cw.localID.String()),
+			zap.String("remote-peer-id", cw.peerID.String()),
+		)
+	}
+
+	for {
+		select {
+		case <-heartbeatc:
+			err := enc.encode(&linkHeartbeatMessage)
+			unflushed += linkHeartbeatMessage.Size()
+			if err == nil {
+				flusher.Flush()
+				batched = 0
+				sentBytes.WithLabelValues(cw.peerID.String()).Add(float64(unflushed))
+				unflushed = 0
+				continue
+			}
+
+			cw.status.deactivate(failureType{source: t.String(), action: "heartbeat"}, err.Error())
+
+			sentFailures.WithLabelValues(cw.peerID.String()).Inc()
+			cw.close()
+			if cw.lg != nil {
+				cw.lg.Warn(
+					"lost TCP streaming connection with remote peer",
+					zap.String("stream-writer-type", t.String()),
+					zap.String("local-member-id", cw.localID.String()),
+					zap.String("remote-peer-id", cw.peerID.String()),
+				)
+			}
+			heartbeatc, msgc = nil, nil
+
+		case m := <-msgc:
+			err := enc.encode(&m)
+			if err == nil {
+				unflushed += m.Size()
+
+				if len(msgc) == 0 || batched > streamBufSize/2 {
+					flusher.Flush()
+					sentBytes.WithLabelValues(cw.peerID.String()).Add(float64(unflushed))
+					unflushed = 0
+					batched = 0
+				} else {
+					batched++
+				}
+
+				continue
+			}
+
+			cw.status.deactivate(failureType{source: t.String(), action: "write"}, err.Error())
+			cw.close()
+			if cw.lg != nil {
+				cw.lg.Warn(
+					"lost TCP streaming connection with remote peer",
+					zap.String("stream-writer-type", t.String()),
+					zap.String("local-member-id", cw.localID.String()),
+					zap.String("remote-peer-id", cw.peerID.String()),
+				)
+			}
+			heartbeatc, msgc = nil, nil
+			cw.r.ReportUnreachable(m.To)
+			sentFailures.WithLabelValues(cw.peerID.String()).Inc()
+
+		case conn := <-cw.connc:
+			cw.mu.Lock()
+			closed := cw.closeUnlocked()
+			t = conn.t
+			switch conn.t {
+			case streamTypeMsgAppV2:
+				enc = newMsgAppV2Encoder(conn.Writer, cw.fs)
+			case streamTypeMessage:
+				enc = &messageEncoder{w: conn.Writer}
+			default:
+				if cw.lg != nil {
+					cw.lg.Panic("unhandled stream type", zap.String("stream-type", t.String()))
+				}
+			}
+			if cw.lg != nil {
+				cw.lg.Info(
+					"set message encoder",
+					zap.String("from", conn.localID.String()),
+					zap.String("to", conn.peerID.String()),
+					zap.String("stream-type", t.String()),
+				)
+			}
+			flusher = conn.Flusher
+			unflushed = 0
+			cw.status.activate()
+			cw.closer = conn.Closer
+			cw.working = true
+			cw.mu.Unlock()
+
+			if closed {
+				if cw.lg != nil {
+					cw.lg.Warn(
+						"closed TCP streaming connection with remote peer",
+						zap.String("stream-writer-type", t.String()),
+						zap.String("local-member-id", cw.localID.String()),
+						zap.String("remote-peer-id", cw.peerID.String()),
+					)
+				}
+			}
+			if cw.lg != nil {
+				cw.lg.Info(
+					"established TCP streaming connection with remote peer",
+					zap.String("stream-writer-type", t.String()),
+					zap.String("local-member-id", cw.localID.String()),
+					zap.String("remote-peer-id", cw.peerID.String()),
+				)
+			}
+			heartbeatc, msgc = tickc.C, cw.msgc
+
+		case <-cw.stopc:
+			if cw.close() {
+				if cw.lg != nil {
+					cw.lg.Warn(
+						"closed TCP streaming connection with remote peer",
+						zap.String("stream-writer-type", t.String()),
+						zap.String("remote-peer-id", cw.peerID.String()),
+					)
+				}
+			}
+			if cw.lg != nil {
+				cw.lg.Info(
+					"stopped TCP streaming connection with remote peer",
+					zap.String("stream-writer-type", t.String()),
+					zap.String("remote-peer-id", cw.peerID.String()),
+				)
+			}
+			close(cw.done)
+			return
+		}
+	}
+}
+
+func (cw *streamWriter) writec() (chan<- raftpb.Message, bool) {
+	cw.mu.Lock()
+	defer cw.mu.Unlock()
+	return cw.msgc, cw.working
+}
+
+func (cw *streamWriter) close() bool {
+	cw.mu.Lock()
+	defer cw.mu.Unlock()
+	return cw.closeUnlocked()
+}
+
+func (cw *streamWriter) closeUnlocked() bool {
+	if !cw.working {
+		return false
+	}
+	if err := cw.closer.Close(); err != nil {
+		if cw.lg != nil {
+			cw.lg.Warn(
+				"failed to close connection with remote peer",
+				zap.String("remote-peer-id", cw.peerID.String()),
+				zap.Error(err),
+			)
+		}
+	}
+	if len(cw.msgc) > 0 {
+		cw.r.ReportUnreachable(uint64(cw.peerID))
+	}
+	cw.msgc = make(chan raftpb.Message, streamBufSize)
+	cw.working = false
+	return true
+}
+
+func (cw *streamWriter) attach(conn *outgoingConn) bool {
+	select {
+	case cw.connc <- conn:
+		return true
+	case <-cw.done:
+		return false
+	}
+}
+
+func (cw *streamWriter) stop() {
+	close(cw.stopc)
+	<-cw.done
+}
+
+// streamReader is a long-running go-routine that dials to the remote stream
+// endpoint and reads messages from the response body returned.
+type streamReader struct {
+	lg *zap.Logger
+
+	peerID types.ID
+	typ    streamType
+
+	tr     *Transport
+	picker *urlPicker
+	status *peerStatus
+	recvc  chan<- raftpb.Message
+	propc  chan<- raftpb.Message
+
+	rl *rate.Limiter // alters the frequency of dial retrial attempts
+
+	errorc chan<- error
+
+	mu     sync.Mutex
+	paused bool
+	closer io.Closer
+
+	ctx    context.Context
+	cancel context.CancelFunc
+	done   chan struct{}
+}
+
+func (cr *streamReader) start() {
+	cr.done = make(chan struct{})
+	if cr.errorc == nil {
+		cr.errorc = cr.tr.ErrorC
+	}
+	if cr.ctx == nil {
+		cr.ctx, cr.cancel = context.WithCancel(context.Background())
+	}
+	go cr.run()
+}
+
+func (cr *streamReader) run() {
+	t := cr.typ
+
+	if cr.lg != nil {
+		cr.lg.Info(
+			"started stream reader with remote peer",
+			zap.String("stream-reader-type", t.String()),
+			zap.String("local-member-id", cr.tr.ID.String()),
+			zap.String("remote-peer-id", cr.peerID.String()),
+		)
+	}
+
+	for {
+		rc, err := cr.dial(t)
+		if err != nil {
+			if !errors.Is(err, errUnsupportedStreamType) {
+				cr.status.deactivate(failureType{source: t.String(), action: "dial"}, err.Error())
+			}
+		} else {
+			cr.status.activate()
+			if cr.lg != nil {
+				cr.lg.Info(
+					"established TCP streaming connection with remote peer",
+					zap.String("stream-reader-type", cr.typ.String()),
+					zap.String("local-member-id", cr.tr.ID.String()),
+					zap.String("remote-peer-id", cr.peerID.String()),
+				)
+			}
+			err = cr.decodeLoop(rc, t)
+			if cr.lg != nil {
+				cr.lg.Warn(
+					"lost TCP streaming connection with remote peer",
+					zap.String("stream-reader-type", cr.typ.String()),
+					zap.String("local-member-id", cr.tr.ID.String()),
+					zap.String("remote-peer-id", cr.peerID.String()),
+					zap.Error(err),
+				)
+			}
+			switch {
+			// all data is read out
+			case errors.Is(err, io.EOF):
+			// connection is closed by the remote
+			case transport.IsClosedConnError(err):
+			default:
+				cr.status.deactivate(failureType{source: t.String(), action: "read"}, err.Error())
+			}
+		}
+		// Wait for a while before new dial attempt
+		err = cr.rl.Wait(cr.ctx)
+		if cr.ctx.Err() != nil {
+			if cr.lg != nil {
+				cr.lg.Info(
+					"stopped stream reader with remote peer",
+					zap.String("stream-reader-type", t.String()),
+					zap.String("local-member-id", cr.tr.ID.String()),
+					zap.String("remote-peer-id", cr.peerID.String()),
+				)
+			}
+			close(cr.done)
+			return
+		}
+		if err != nil {
+			if cr.lg != nil {
+				cr.lg.Warn(
+					"rate limit on stream reader with remote peer",
+					zap.String("stream-reader-type", t.String()),
+					zap.String("local-member-id", cr.tr.ID.String()),
+					zap.String("remote-peer-id", cr.peerID.String()),
+					zap.Error(err),
+				)
+			}
+		}
+	}
+}
+
+func (cr *streamReader) decodeLoop(rc io.ReadCloser, t streamType) error {
+	var dec decoder
+	cr.mu.Lock()
+	switch t {
+	case streamTypeMsgAppV2:
+		dec = newMsgAppV2Decoder(rc, cr.tr.ID, cr.peerID)
+	case streamTypeMessage:
+		dec = &messageDecoder{r: rc}
+	default:
+		if cr.lg != nil {
+			cr.lg.Panic("unknown stream type", zap.String("type", t.String()))
+		}
+	}
+	select {
+	case <-cr.ctx.Done():
+		cr.mu.Unlock()
+		if err := rc.Close(); err != nil {
+			return err
+		}
+		return io.EOF
+	default:
+		cr.closer = rc
+	}
+	cr.mu.Unlock()
+
+	// gofail: labelRaftDropHeartbeat:
+	for {
+		m, err := dec.decode()
+		if err != nil {
+			cr.mu.Lock()
+			cr.close()
+			cr.mu.Unlock()
+			return err
+		}
+
+		// gofail-go: var raftDropHeartbeat struct{}
+		// continue labelRaftDropHeartbeat
+		receivedBytes.WithLabelValues(types.ID(m.From).String()).Add(float64(m.Size()))
+
+		cr.mu.Lock()
+		paused := cr.paused
+		cr.mu.Unlock()
+
+		if paused {
+			continue
+		}
+
+		if isLinkHeartbeatMessage(&m) {
+			// raft is not interested in link layer
+			// heartbeat message, so we should ignore
+			// it.
+			continue
+		}
+
+		recvc := cr.recvc
+		if m.Type == raftpb.MsgProp {
+			recvc = cr.propc
+		}
+
+		select {
+		case recvc <- m:
+		default:
+			if cr.status.isActive() {
+				if cr.lg != nil {
+					cr.lg.Warn(
+						"dropped internal Raft message since receiving buffer is full (overloaded network)",
+						zap.String("message-type", m.Type.String()),
+						zap.String("local-member-id", cr.tr.ID.String()),
+						zap.String("from", types.ID(m.From).String()),
+						zap.String("remote-peer-id", types.ID(m.To).String()),
+						zap.Bool("remote-peer-active", cr.status.isActive()),
+					)
+				}
+			} else {
+				if cr.lg != nil {
+					cr.lg.Warn(
+						"dropped Raft message since receiving buffer is full (overloaded network)",
+						zap.String("message-type", m.Type.String()),
+						zap.String("local-member-id", cr.tr.ID.String()),
+						zap.String("from", types.ID(m.From).String()),
+						zap.String("remote-peer-id", types.ID(m.To).String()),
+						zap.Bool("remote-peer-active", cr.status.isActive()),
+					)
+				}
+			}
+			recvFailures.WithLabelValues(types.ID(m.From).String()).Inc()
+		}
+	}
+}
+
+func (cr *streamReader) stop() {
+	cr.mu.Lock()
+	cr.cancel()
+	cr.close()
+	cr.mu.Unlock()
+	<-cr.done
+}
+
+func (cr *streamReader) dial(t streamType) (io.ReadCloser, error) {
+	u := cr.picker.pick()
+	uu := u
+	uu.Path = path.Join(t.endpoint(cr.lg), cr.tr.ID.String())
+
+	if cr.lg != nil {
+		cr.lg.Debug(
+			"dial stream reader",
+			zap.String("from", cr.tr.ID.String()),
+			zap.String("to", cr.peerID.String()),
+			zap.String("address", uu.String()),
+		)
+	}
+	req, err := http.NewRequest(http.MethodGet, uu.String(), nil)
+	if err != nil {
+		cr.picker.unreachable(u)
+		return nil, fmt.Errorf("failed to make http request to %v (%w)", u, err)
+	}
+	req.Header.Set("X-Server-From", cr.tr.ID.String())
+	req.Header.Set("X-Server-Version", version.Version)
+	req.Header.Set("X-Min-Cluster-Version", version.MinClusterVersion)
+	req.Header.Set("X-Etcd-Cluster-ID", cr.tr.ClusterID.String())
+	req.Header.Set("X-Raft-To", cr.peerID.String())
+
+	setPeerURLsHeader(req, cr.tr.URLs)
+
+	req = req.WithContext(cr.ctx)
+
+	cr.mu.Lock()
+	select {
+	case <-cr.ctx.Done():
+		cr.mu.Unlock()
+		return nil, fmt.Errorf("stream reader is stopped")
+	default:
+	}
+	cr.mu.Unlock()
+
+	resp, err := cr.tr.streamRt.RoundTrip(req)
+	if err != nil {
+		cr.picker.unreachable(u)
+		return nil, err
+	}
+
+	rv := serverVersion(resp.Header)
+	lv := semver.Must(semver.NewVersion(version.Version))
+	if compareMajorMinorVersion(rv, lv) == -1 && !checkStreamSupport(rv, t) {
+		httputil.GracefulClose(resp)
+		cr.picker.unreachable(u)
+		return nil, errUnsupportedStreamType
+	}
+
+	switch resp.StatusCode {
+	case http.StatusGone:
+		httputil.GracefulClose(resp)
+		cr.picker.unreachable(u)
+		reportCriticalError(errMemberRemoved, cr.errorc)
+		return nil, errMemberRemoved
+
+	case http.StatusOK:
+		return resp.Body, nil
+
+	case http.StatusNotFound:
+		httputil.GracefulClose(resp)
+		cr.picker.unreachable(u)
+		return nil, fmt.Errorf("peer %s failed to find local node %s", cr.peerID, cr.tr.ID)
+
+	case http.StatusPreconditionFailed:
+		b, err := io.ReadAll(resp.Body)
+		if err != nil {
+			cr.picker.unreachable(u)
+			return nil, err
+		}
+		httputil.GracefulClose(resp)
+		cr.picker.unreachable(u)
+
+		switch strings.TrimSuffix(string(b), "\n") {
+		case errIncompatibleVersion.Error():
+			if cr.lg != nil {
+				cr.lg.Warn(
+					"request sent was ignored by remote peer due to server version incompatibility",
+					zap.String("local-member-id", cr.tr.ID.String()),
+					zap.String("remote-peer-id", cr.peerID.String()),
+					zap.Error(errIncompatibleVersion),
+				)
+			}
+			return nil, errIncompatibleVersion
+
+		case ErrClusterIDMismatch.Error():
+			if cr.lg != nil {
+				cr.lg.Warn(
+					"request sent was ignored by remote peer due to cluster ID mismatch",
+					zap.String("remote-peer-id", cr.peerID.String()),
+					zap.String("remote-peer-cluster-id", resp.Header.Get("X-Etcd-Cluster-ID")),
+					zap.String("local-member-id", cr.tr.ID.String()),
+					zap.String("local-member-cluster-id", cr.tr.ClusterID.String()),
+					zap.Error(ErrClusterIDMismatch),
+				)
+			}
+			return nil, ErrClusterIDMismatch
+
+		default:
+			return nil, fmt.Errorf("unhandled error %q when precondition failed", string(b))
+		}
+
+	default:
+		httputil.GracefulClose(resp)
+		cr.picker.unreachable(u)
+		return nil, fmt.Errorf("unhandled http status %d", resp.StatusCode)
+	}
+}
+
+func (cr *streamReader) close() {
+	if cr.closer != nil {
+		if err := cr.closer.Close(); err != nil {
+			if cr.lg != nil {
+				cr.lg.Warn(
+					"failed to close remote peer connection",
+					zap.String("local-member-id", cr.tr.ID.String()),
+					zap.String("remote-peer-id", cr.peerID.String()),
+					zap.Error(err),
+				)
+			}
+		}
+	}
+	cr.closer = nil
+}
+
+func (cr *streamReader) pause() {
+	cr.mu.Lock()
+	defer cr.mu.Unlock()
+	cr.paused = true
+}
+
+func (cr *streamReader) resume() {
+	cr.mu.Lock()
+	defer cr.mu.Unlock()
+	cr.paused = false
+}
+
+// checkStreamSupport checks whether the stream type is supported in the
+// given version.
+func checkStreamSupport(v *semver.Version, t streamType) bool {
+	nv := &semver.Version{Major: v.Major, Minor: v.Minor}
+	for _, s := range supportedStream[nv.String()] {
+		if s == t {
+			return true
+		}
+	}
+	return false
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/transport.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/transport.go
new file mode 100644
index 0000000..b376d57
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/transport.go
@@ -0,0 +1,453 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package rafthttp
+
+import (
+	"context"
+	"net/http"
+	"sync"
+	"time"
+
+	"github.com/xiang90/probing"
+	"go.uber.org/zap"
+	"golang.org/x/time/rate"
+
+	"go.etcd.io/etcd/client/pkg/v3/transport"
+	"go.etcd.io/etcd/client/pkg/v3/types"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/snap"
+	stats "go.etcd.io/etcd/server/v3/etcdserver/api/v2stats"
+	"go.etcd.io/raft/v3"
+	"go.etcd.io/raft/v3/raftpb"
+)
+
+type Raft interface {
+	Process(ctx context.Context, m raftpb.Message) error
+	IsIDRemoved(id uint64) bool
+	ReportUnreachable(id uint64)
+	ReportSnapshot(id uint64, status raft.SnapshotStatus)
+}
+
+type Transporter interface {
+	// Start starts the given Transporter.
+	// Start MUST be called before calling other functions in the interface.
+	Start() error
+	// Handler returns the HTTP handler of the transporter.
+	// A transporter HTTP handler handles the HTTP requests
+	// from remote peers.
+	// The handler MUST be used to handle RaftPrefix(/raft)
+	// endpoint.
+	Handler() http.Handler
+	// Send sends out the given messages to the remote peers.
+	// Each message has a To field, which is an id that maps
+	// to an existing peer in the transport.
+	// If the id cannot be found in the transport, the message
+	// will be ignored.
+	Send(m []raftpb.Message)
+	// SendSnapshot sends out the given snapshot message to a remote peer.
+	// The behavior of SendSnapshot is similar to Send.
+	SendSnapshot(m snap.Message)
+	// AddRemote adds a remote with given peer urls into the transport.
+	// A remote helps newly joined member to catch up the progress of cluster,
+	// and will not be used after that.
+	// It is the caller's responsibility to ensure the urls are all valid,
+	// or it panics.
+	AddRemote(id types.ID, urls []string)
+	// AddPeer adds a peer with given peer urls into the transport.
+	// It is the caller's responsibility to ensure the urls are all valid,
+	// or it panics.
+	// Peer urls are used to connect to the remote peer.
+	AddPeer(id types.ID, urls []string)
+	// RemovePeer removes the peer with given id.
+	RemovePeer(id types.ID)
+	// RemoveAllPeers removes all the existing peers in the transport.
+	RemoveAllPeers()
+	// UpdatePeer updates the peer urls of the peer with the given id.
+	// It is the caller's responsibility to ensure the urls are all valid,
+	// or it panics.
+	UpdatePeer(id types.ID, urls []string)
+	// ActiveSince returns the time that the connection with the peer
+	// of the given id becomes active.
+	// If the connection is active since peer was added, it returns the adding time.
+	// If the connection is currently inactive, it returns zero time.
+	ActiveSince(id types.ID) time.Time
+	// ActivePeers returns the number of active peers.
+	ActivePeers() int
+	// Stop closes the connections and stops the transporter.
+	Stop()
+}
+
+// Transport implements Transporter interface. It provides the functionality
+// to send raft messages to peers, and receive raft messages from peers.
+// User should call Handler method to get a handler to serve requests
+// received from peerURLs.
+// User needs to call Start before calling other functions, and call
+// Stop when the Transport is no longer used.
+type Transport struct {
+	Logger *zap.Logger
+
+	DialTimeout time.Duration // maximum duration before timing out dial of the request
+	// DialRetryFrequency defines the frequency of streamReader dial retrial attempts;
+	// a distinct rate limiter is created per every peer (default value: 10 events/sec)
+	DialRetryFrequency rate.Limit
+
+	TLSInfo transport.TLSInfo // TLS information used when creating connection
+
+	ID          types.ID   // local member ID
+	URLs        types.URLs // local peer URLs
+	ClusterID   types.ID   // raft cluster ID for request validation
+	Raft        Raft       // raft state machine, to which the Transport forwards received messages and reports status
+	Snapshotter *snap.Snapshotter
+	ServerStats *stats.ServerStats // used to record general transportation statistics
+	// LeaderStats records transportation statistics with followers when
+	// performing as leader in raft protocol
+	LeaderStats *stats.LeaderStats
+	// ErrorC is used to report detected critical errors, e.g.,
+	// the member has been permanently removed from the cluster
+	// When an error is received from ErrorC, user should stop raft state
+	// machine and thus stop the Transport.
+	ErrorC chan error
+
+	streamRt   http.RoundTripper // roundTripper used by streams
+	pipelineRt http.RoundTripper // roundTripper used by pipelines
+
+	mu      sync.RWMutex         // protect the remote and peer map
+	remotes map[types.ID]*remote // remotes map that helps newly joined member to catch up
+	peers   map[types.ID]Peer    // peers map
+
+	pipelineProber probing.Prober
+	streamProber   probing.Prober
+}
+
+func (t *Transport) Start() error {
+	var err error
+	t.streamRt, err = newStreamRoundTripper(t.TLSInfo, t.DialTimeout)
+	if err != nil {
+		return err
+	}
+	t.pipelineRt, err = NewRoundTripper(t.TLSInfo, t.DialTimeout)
+	if err != nil {
+		return err
+	}
+	t.remotes = make(map[types.ID]*remote)
+	t.peers = make(map[types.ID]Peer)
+	t.pipelineProber = probing.NewProber(t.pipelineRt)
+	t.streamProber = probing.NewProber(t.streamRt)
+
+	// If client didn't provide dial retry frequency, use the default
+	// (100ms backoff between attempts to create a new stream),
+	// so it doesn't bring too much overhead when retry.
+	if t.DialRetryFrequency == 0 {
+		t.DialRetryFrequency = rate.Every(100 * time.Millisecond)
+	}
+	return nil
+}
+
+func (t *Transport) Handler() http.Handler {
+	pipelineHandler := newPipelineHandler(t, t.Raft, t.ClusterID)
+	streamHandler := newStreamHandler(t, t, t.Raft, t.ID, t.ClusterID)
+	snapHandler := newSnapshotHandler(t, t.Raft, t.Snapshotter, t.ClusterID)
+	mux := http.NewServeMux()
+	mux.Handle(RaftPrefix, pipelineHandler)
+	mux.Handle(RaftStreamPrefix+"/", streamHandler)
+	mux.Handle(RaftSnapshotPrefix, snapHandler)
+	mux.Handle(ProbingPrefix, probing.NewHandler())
+	return mux
+}
+
+func (t *Transport) Get(id types.ID) Peer {
+	t.mu.RLock()
+	defer t.mu.RUnlock()
+	return t.peers[id]
+}
+
+func (t *Transport) Send(msgs []raftpb.Message) {
+	for _, m := range msgs {
+		if m.To == 0 {
+			// ignore intentionally dropped message
+			continue
+		}
+		to := types.ID(m.To)
+
+		t.mu.RLock()
+		p, pok := t.peers[to]
+		g, rok := t.remotes[to]
+		t.mu.RUnlock()
+
+		if pok {
+			if isMsgApp(m) {
+				t.ServerStats.SendAppendReq(m.Size())
+			}
+			p.send(m)
+			continue
+		}
+
+		if rok {
+			g.send(m)
+			continue
+		}
+
+		if t.Logger != nil {
+			t.Logger.Debug(
+				"ignored message send request; unknown remote peer target",
+				zap.String("type", m.Type.String()),
+				zap.String("unknown-target-peer-id", to.String()),
+			)
+		}
+	}
+}
+
+func (t *Transport) Stop() {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	for _, r := range t.remotes {
+		r.stop()
+	}
+	for _, p := range t.peers {
+		p.stop()
+	}
+	t.pipelineProber.RemoveAll()
+	t.streamProber.RemoveAll()
+	if tr, ok := t.streamRt.(*http.Transport); ok {
+		tr.CloseIdleConnections()
+	}
+	if tr, ok := t.pipelineRt.(*http.Transport); ok {
+		tr.CloseIdleConnections()
+	}
+	t.peers = nil
+	t.remotes = nil
+}
+
+// CutPeer drops messages to the specified peer.
+func (t *Transport) CutPeer(id types.ID) {
+	t.mu.RLock()
+	p, pok := t.peers[id]
+	g, gok := t.remotes[id]
+	t.mu.RUnlock()
+
+	if pok {
+		p.(Pausable).Pause()
+	}
+	if gok {
+		g.Pause()
+	}
+}
+
+// MendPeer recovers the message dropping behavior of the given peer.
+func (t *Transport) MendPeer(id types.ID) {
+	t.mu.RLock()
+	p, pok := t.peers[id]
+	g, gok := t.remotes[id]
+	t.mu.RUnlock()
+
+	if pok {
+		p.(Pausable).Resume()
+	}
+	if gok {
+		g.Resume()
+	}
+}
+
+func (t *Transport) AddRemote(id types.ID, us []string) {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	if t.remotes == nil {
+		// there's no clean way to shutdown the golang http server
+		// (see: https://github.com/golang/go/issues/4674) before
+		// stopping the transport; ignore any new connections.
+		return
+	}
+	if _, ok := t.peers[id]; ok {
+		return
+	}
+	if _, ok := t.remotes[id]; ok {
+		return
+	}
+	urls, err := types.NewURLs(us)
+	if err != nil {
+		if t.Logger != nil {
+			t.Logger.Panic("failed NewURLs", zap.Strings("urls", us), zap.Error(err))
+		}
+	}
+	t.remotes[id] = startRemote(t, urls, id)
+
+	if t.Logger != nil {
+		t.Logger.Info(
+			"added new remote peer",
+			zap.String("local-member-id", t.ID.String()),
+			zap.String("remote-peer-id", id.String()),
+			zap.Strings("remote-peer-urls", us),
+		)
+	}
+}
+
+func (t *Transport) AddPeer(id types.ID, us []string) {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+
+	if t.peers == nil {
+		panic("transport stopped")
+	}
+	if _, ok := t.peers[id]; ok {
+		return
+	}
+	urls, err := types.NewURLs(us)
+	if err != nil {
+		if t.Logger != nil {
+			t.Logger.Panic("failed NewURLs", zap.Strings("urls", us), zap.Error(err))
+		}
+	}
+	fs := t.LeaderStats.Follower(id.String())
+	t.peers[id] = startPeer(t, urls, id, fs)
+	addPeerToProber(t.Logger, t.pipelineProber, id.String(), us, RoundTripperNameSnapshot, rttSec)
+	addPeerToProber(t.Logger, t.streamProber, id.String(), us, RoundTripperNameRaftMessage, rttSec)
+
+	if t.Logger != nil {
+		t.Logger.Info(
+			"added remote peer",
+			zap.String("local-member-id", t.ID.String()),
+			zap.String("remote-peer-id", id.String()),
+			zap.Strings("remote-peer-urls", us),
+		)
+	}
+}
+
+func (t *Transport) RemovePeer(id types.ID) {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	t.removePeer(id)
+}
+
+func (t *Transport) RemoveAllPeers() {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	for id := range t.peers {
+		t.removePeer(id)
+	}
+}
+
+// the caller of this function must have the peers mutex.
+func (t *Transport) removePeer(id types.ID) {
+	// etcd may remove a member again on startup due to WAL files replaying.
+	peer, ok := t.peers[id]
+	if ok {
+		peer.stop()
+		delete(t.peers, id)
+		delete(t.LeaderStats.Followers, id.String())
+		t.pipelineProber.Remove(id.String())
+		t.streamProber.Remove(id.String())
+	}
+
+	if t.Logger != nil {
+		if ok {
+			t.Logger.Info(
+				"removed remote peer",
+				zap.String("local-member-id", t.ID.String()),
+				zap.String("removed-remote-peer-id", id.String()),
+			)
+		} else {
+			t.Logger.Warn(
+				"skipped removing already removed peer",
+				zap.String("local-member-id", t.ID.String()),
+				zap.String("removed-remote-peer-id", id.String()),
+			)
+		}
+	}
+}
+
+func (t *Transport) UpdatePeer(id types.ID, us []string) {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	// TODO: return error or just panic?
+	if _, ok := t.peers[id]; !ok {
+		return
+	}
+	urls, err := types.NewURLs(us)
+	if err != nil {
+		if t.Logger != nil {
+			t.Logger.Panic("failed NewURLs", zap.Strings("urls", us), zap.Error(err))
+		}
+	}
+	t.peers[id].update(urls)
+
+	t.pipelineProber.Remove(id.String())
+	addPeerToProber(t.Logger, t.pipelineProber, id.String(), us, RoundTripperNameSnapshot, rttSec)
+	t.streamProber.Remove(id.String())
+	addPeerToProber(t.Logger, t.streamProber, id.String(), us, RoundTripperNameRaftMessage, rttSec)
+
+	if t.Logger != nil {
+		t.Logger.Info(
+			"updated remote peer",
+			zap.String("local-member-id", t.ID.String()),
+			zap.String("updated-remote-peer-id", id.String()),
+			zap.Strings("updated-remote-peer-urls", us),
+		)
+	}
+}
+
+func (t *Transport) ActiveSince(id types.ID) time.Time {
+	t.mu.RLock()
+	defer t.mu.RUnlock()
+	if p, ok := t.peers[id]; ok {
+		return p.activeSince()
+	}
+	return time.Time{}
+}
+
+func (t *Transport) SendSnapshot(m snap.Message) {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	p := t.peers[types.ID(m.To)]
+	if p == nil {
+		m.CloseWithError(errMemberNotFound)
+		return
+	}
+	p.sendSnap(m)
+}
+
+// Pausable is a testing interface for pausing transport traffic.
+type Pausable interface {
+	Pause()
+	Resume()
+}
+
+func (t *Transport) Pause() {
+	t.mu.RLock()
+	defer t.mu.RUnlock()
+	for _, p := range t.peers {
+		p.(Pausable).Pause()
+	}
+}
+
+func (t *Transport) Resume() {
+	t.mu.RLock()
+	defer t.mu.RUnlock()
+	for _, p := range t.peers {
+		p.(Pausable).Resume()
+	}
+}
+
+// ActivePeers returns a channel that closes when an initial
+// peer connection has been established. Use this to wait until the
+// first peer connection becomes active.
+func (t *Transport) ActivePeers() (cnt int) {
+	t.mu.RLock()
+	defer t.mu.RUnlock()
+	for _, p := range t.peers {
+		if !p.activeSince().IsZero() {
+			cnt++
+		}
+	}
+	return cnt
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/urlpick.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/urlpick.go
new file mode 100644
index 0000000..fc6054a
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/urlpick.go
@@ -0,0 +1,57 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package rafthttp
+
+import (
+	"net/url"
+	"sync"
+
+	"go.etcd.io/etcd/client/pkg/v3/types"
+)
+
+type urlPicker struct {
+	mu     sync.Mutex // guards urls and picked
+	urls   types.URLs
+	picked int
+}
+
+func newURLPicker(urls types.URLs) *urlPicker {
+	return &urlPicker{
+		urls: urls,
+	}
+}
+
+func (p *urlPicker) update(urls types.URLs) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	p.urls = urls
+	p.picked = 0
+}
+
+func (p *urlPicker) pick() url.URL {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	return p.urls[p.picked]
+}
+
+// unreachable notices the picker that the given url is unreachable,
+// and it should use other possible urls.
+func (p *urlPicker) unreachable(u url.URL) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	if u == p.urls[p.picked] {
+		p.picked = (p.picked + 1) % len(p.urls)
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/util.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/util.go
new file mode 100644
index 0000000..5057f53
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp/util.go
@@ -0,0 +1,205 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package rafthttp
+
+import (
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"net/url"
+	"strings"
+	"time"
+
+	"github.com/coreos/go-semver/semver"
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/api/v3/version"
+	"go.etcd.io/etcd/client/pkg/v3/transport"
+	"go.etcd.io/etcd/client/pkg/v3/types"
+)
+
+var (
+	errMemberRemoved  = fmt.Errorf("the member has been permanently removed from the cluster")
+	errMemberNotFound = fmt.Errorf("member not found")
+)
+
+// NewListener returns a listener for raft message transfer between peers.
+// It uses timeout listener to identify broken streams promptly.
+func NewListener(u url.URL, tlsinfo *transport.TLSInfo) (net.Listener, error) {
+	return transport.NewListenerWithOpts(u.Host, u.Scheme, transport.WithTLSInfo(tlsinfo), transport.WithTimeout(ConnReadTimeout, ConnWriteTimeout))
+}
+
+// NewRoundTripper returns a roundTripper used to send requests
+// to rafthttp listener of remote peers.
+func NewRoundTripper(tlsInfo transport.TLSInfo, dialTimeout time.Duration) (http.RoundTripper, error) {
+	// It uses timeout transport to pair with remote timeout listeners.
+	// It sets no read/write timeout, because message in requests may
+	// take long time to write out before reading out the response.
+	return transport.NewTimeoutTransport(tlsInfo, dialTimeout, 0, 0)
+}
+
+// newStreamRoundTripper returns a roundTripper used to send stream requests
+// to rafthttp listener of remote peers.
+// Read/write timeout is set for stream roundTripper to promptly
+// find out broken status, which minimizes the number of messages
+// sent on broken connection.
+func newStreamRoundTripper(tlsInfo transport.TLSInfo, dialTimeout time.Duration) (http.RoundTripper, error) {
+	return transport.NewTimeoutTransport(tlsInfo, dialTimeout, ConnReadTimeout, ConnWriteTimeout)
+}
+
+// createPostRequest creates a HTTP POST request that sends raft message.
+func createPostRequest(lg *zap.Logger, u url.URL, path string, body io.Reader, ct string, urls types.URLs, from, cid types.ID) *http.Request {
+	uu := u
+	uu.Path = path
+	req, err := http.NewRequest(http.MethodPost, uu.String(), body)
+	if err != nil {
+		if lg != nil {
+			lg.Panic("unexpected new request error", zap.Error(err))
+		}
+	}
+	req.Header.Set("Content-Type", ct)
+	req.Header.Set("X-Server-From", from.String())
+	req.Header.Set("X-Server-Version", version.Version)
+	req.Header.Set("X-Min-Cluster-Version", version.MinClusterVersion)
+	req.Header.Set("X-Etcd-Cluster-ID", cid.String())
+	setPeerURLsHeader(req, urls)
+
+	return req
+}
+
+// checkPostResponse checks the response of the HTTP POST request that sends
+// raft message.
+func checkPostResponse(lg *zap.Logger, resp *http.Response, body []byte, req *http.Request, to types.ID) error {
+	switch resp.StatusCode {
+	case http.StatusPreconditionFailed:
+		switch strings.TrimSuffix(string(body), "\n") {
+		case errIncompatibleVersion.Error():
+			if lg != nil {
+				lg.Error(
+					"request sent was ignored by peer",
+					zap.String("remote-peer-id", to.String()),
+				)
+			}
+			return errIncompatibleVersion
+		case ErrClusterIDMismatch.Error():
+			if lg != nil {
+				lg.Error(
+					"request sent was ignored due to cluster ID mismatch",
+					zap.String("remote-peer-id", to.String()),
+					zap.String("remote-peer-cluster-id", resp.Header.Get("X-Etcd-Cluster-ID")),
+					zap.String("local-member-cluster-id", req.Header.Get("X-Etcd-Cluster-ID")),
+				)
+			}
+			return ErrClusterIDMismatch
+		default:
+			return fmt.Errorf("unhandled error %q when precondition failed", string(body))
+		}
+	case http.StatusForbidden:
+		return errMemberRemoved
+	case http.StatusNoContent:
+		return nil
+	default:
+		return fmt.Errorf("unexpected http status %s while posting to %q", http.StatusText(resp.StatusCode), req.URL.String())
+	}
+}
+
+// reportCriticalError reports the given error through sending it into
+// the given error channel.
+// If the error channel is filled up when sending error, it drops the error
+// because the fact that error has happened is reported, which is
+// good enough.
+func reportCriticalError(err error, errc chan<- error) {
+	select {
+	case errc <- err:
+	default:
+	}
+}
+
+// compareMajorMinorVersion returns an integer comparing two versions based on
+// their major and minor version. The result will be 0 if a==b, -1 if a < b,
+// and 1 if a > b.
+func compareMajorMinorVersion(a, b *semver.Version) int {
+	na := &semver.Version{Major: a.Major, Minor: a.Minor}
+	nb := &semver.Version{Major: b.Major, Minor: b.Minor}
+	switch {
+	case na.LessThan(*nb):
+		return -1
+	case nb.LessThan(*na):
+		return 1
+	default:
+		return 0
+	}
+}
+
+// serverVersion returns the server version from the given header.
+func serverVersion(h http.Header) *semver.Version {
+	verStr := h.Get("X-Server-Version")
+	// backward compatibility with etcd 2.0
+	if verStr == "" {
+		verStr = "2.0.0"
+	}
+	return semver.Must(semver.NewVersion(verStr))
+}
+
+// serverVersion returns the min cluster version from the given header.
+func minClusterVersion(h http.Header) *semver.Version {
+	verStr := h.Get("X-Min-Cluster-Version")
+	// backward compatibility with etcd 2.0
+	if verStr == "" {
+		verStr = "2.0.0"
+	}
+	return semver.Must(semver.NewVersion(verStr))
+}
+
+// checkVersionCompatibility checks whether the given version is compatible
+// with the local version.
+func checkVersionCompatibility(name string, server, minCluster *semver.Version) (
+	localServer *semver.Version,
+	localMinCluster *semver.Version,
+	err error,
+) {
+	localServer = semver.Must(semver.NewVersion(version.Version))
+	localMinCluster = semver.Must(semver.NewVersion(version.MinClusterVersion))
+	if compareMajorMinorVersion(server, localMinCluster) == -1 {
+		return localServer, localMinCluster, fmt.Errorf("remote version is too low: remote[%s]=%s, local=%s", name, server, localServer)
+	}
+	if compareMajorMinorVersion(minCluster, localServer) == 1 {
+		return localServer, localMinCluster, fmt.Errorf("local version is too low: remote[%s]=%s, local=%s", name, server, localServer)
+	}
+	return localServer, localMinCluster, nil
+}
+
+// setPeerURLsHeader reports local urls for peer discovery
+func setPeerURLsHeader(req *http.Request, urls types.URLs) {
+	if urls == nil {
+		// often not set in unit tests
+		return
+	}
+	peerURLs := make([]string, urls.Len())
+	for i := range urls {
+		peerURLs[i] = urls[i].String()
+	}
+	req.Header.Set("X-PeerURLs", strings.Join(peerURLs, ","))
+}
+
+// addRemoteFromRequest adds a remote peer according to an http request header
+func addRemoteFromRequest(tr Transporter, r *http.Request) {
+	if from, err := types.IDFromString(r.Header.Get("X-Server-From")); err == nil {
+		if urls := r.Header.Get("X-PeerURLs"); urls != "" {
+			tr.AddRemote(from, strings.Split(urls, ","))
+		}
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/snap/db.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/snap/db.go
new file mode 100644
index 0000000..e8add5e
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/snap/db.go
@@ -0,0 +1,99 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package snap
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"time"
+
+	humanize "github.com/dustin/go-humanize"
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/client/pkg/v3/fileutil"
+)
+
+var ErrNoDBSnapshot = errors.New("snap: snapshot file doesn't exist")
+
+// SaveDBFrom saves snapshot of the database from the given reader. It
+// guarantees the save operation is atomic.
+func (s *Snapshotter) SaveDBFrom(r io.Reader, id uint64) (int64, error) {
+	start := time.Now()
+
+	f, err := os.CreateTemp(s.dir, "tmp")
+	if err != nil {
+		return 0, err
+	}
+	var n int64
+	n, err = io.Copy(f, r)
+	if err == nil {
+		fsyncStart := time.Now()
+		err = fileutil.Fsync(f)
+		snapDBFsyncSec.Observe(time.Since(fsyncStart).Seconds())
+	}
+	f.Close()
+	if err != nil {
+		os.Remove(f.Name())
+		return n, err
+	}
+	fn := s.dbFilePath(id)
+	if fileutil.Exist(fn) {
+		os.Remove(f.Name())
+		return n, nil
+	}
+	err = os.Rename(f.Name(), fn)
+	if err != nil {
+		os.Remove(f.Name())
+		return n, err
+	}
+
+	s.lg.Info(
+		"saved database snapshot to disk",
+		zap.String("path", fn),
+		zap.Int64("bytes", n),
+		zap.String("size", humanize.Bytes(uint64(n))),
+	)
+
+	snapDBSaveSec.Observe(time.Since(start).Seconds())
+	return n, nil
+}
+
+// DBFilePath returns the file path for the snapshot of the database with
+// given id. If the snapshot does not exist, it returns error.
+func (s *Snapshotter) DBFilePath(id uint64) (string, error) {
+	if _, err := fileutil.ReadDir(s.dir); err != nil {
+		return "", err
+	}
+	fn := s.dbFilePath(id)
+	if fileutil.Exist(fn) {
+		return fn, nil
+	}
+	if s.lg != nil {
+		s.lg.Warn(
+			"failed to find [SNAPSHOT-INDEX].snap.db",
+			zap.Uint64("snapshot-index", id),
+			zap.String("snapshot-file-path", fn),
+			zap.Error(ErrNoDBSnapshot),
+		)
+	}
+	return "", ErrNoDBSnapshot
+}
+
+func (s *Snapshotter) dbFilePath(id uint64) string {
+	return filepath.Join(s.dir, fmt.Sprintf("%016x.snap.db", id))
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/snap/doc.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/snap/doc.go
new file mode 100644
index 0000000..dcc5db5
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/snap/doc.go
@@ -0,0 +1,17 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package snap handles Raft nodes' states with snapshots.
+// The snapshot logic is internal to etcd server and raft package.
+package snap
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/snap/message.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/snap/message.go
new file mode 100644
index 0000000..2b4090c
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/snap/message.go
@@ -0,0 +1,64 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package snap
+
+import (
+	"io"
+
+	"go.etcd.io/etcd/pkg/v3/ioutil"
+	"go.etcd.io/raft/v3/raftpb"
+)
+
+// Message is a struct that contains a raft Message and a ReadCloser. The type
+// of raft message MUST be MsgSnap, which contains the raft meta-data and an
+// additional data []byte field that contains the snapshot of the actual state
+// machine.
+// Message contains the ReadCloser field for handling large snapshot. This avoid
+// copying the entire snapshot into a byte array, which consumes a lot of memory.
+//
+// User of Message should close the Message after sending it.
+type Message struct {
+	raftpb.Message
+	ReadCloser io.ReadCloser
+	TotalSize  int64
+	closeC     chan bool
+}
+
+func NewMessage(rs raftpb.Message, rc io.ReadCloser, rcSize int64) *Message {
+	return &Message{
+		Message:    rs,
+		ReadCloser: ioutil.NewExactReadCloser(rc, rcSize),
+		TotalSize:  int64(rs.Size()) + rcSize,
+		closeC:     make(chan bool, 1),
+	}
+}
+
+// CloseNotify returns a channel that receives a single value
+// when the message sent is finished. true indicates the sent
+// is successful.
+func (m Message) CloseNotify() <-chan bool {
+	return m.closeC
+}
+
+func (m Message) CloseWithError(err error) {
+	if cerr := m.ReadCloser.Close(); cerr != nil {
+		err = cerr
+	}
+	if err == nil {
+		m.closeC <- true
+	} else {
+		m.closeC <- false
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/snap/metrics.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/snap/metrics.go
new file mode 100644
index 0000000..2affecf
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/snap/metrics.go
@@ -0,0 +1,82 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package snap
+
+import "github.com/prometheus/client_golang/prometheus"
+
+var (
+	snapMarshallingSec = prometheus.NewHistogram(prometheus.HistogramOpts{
+		Namespace: "etcd_debugging",
+		Subsystem: "snap",
+		Name:      "save_marshalling_duration_seconds",
+		Help:      "The marshalling cost distributions of save called by snapshot.",
+
+		// lowest bucket start of upper bound 0.001 sec (1 ms) with factor 2
+		// highest bucket start of 0.001 sec * 2^13 == 8.192 sec
+		Buckets: prometheus.ExponentialBuckets(0.001, 2, 14),
+	})
+
+	snapSaveSec = prometheus.NewHistogram(prometheus.HistogramOpts{
+		Namespace: "etcd_debugging",
+		Subsystem: "snap",
+		Name:      "save_total_duration_seconds",
+		Help:      "The total latency distributions of save called by snapshot.",
+
+		// lowest bucket start of upper bound 0.001 sec (1 ms) with factor 2
+		// highest bucket start of 0.001 sec * 2^13 == 8.192 sec
+		Buckets: prometheus.ExponentialBuckets(0.001, 2, 14),
+	})
+
+	snapFsyncSec = prometheus.NewHistogram(prometheus.HistogramOpts{
+		Namespace: "etcd",
+		Subsystem: "snap",
+		Name:      "fsync_duration_seconds",
+		Help:      "The latency distributions of fsync called by snap.",
+
+		// lowest bucket start of upper bound 0.001 sec (1 ms) with factor 2
+		// highest bucket start of 0.001 sec * 2^13 == 8.192 sec
+		Buckets: prometheus.ExponentialBuckets(0.001, 2, 14),
+	})
+
+	snapDBSaveSec = prometheus.NewHistogram(prometheus.HistogramOpts{
+		Namespace: "etcd",
+		Subsystem: "snap_db",
+		Name:      "save_total_duration_seconds",
+		Help:      "The total latency distributions of v3 snapshot save",
+
+		// lowest bucket start of upper bound 0.1 sec (100 ms) with factor 2
+		// highest bucket start of 0.1 sec * 2^9 == 51.2 sec
+		Buckets: prometheus.ExponentialBuckets(0.1, 2, 10),
+	})
+
+	snapDBFsyncSec = prometheus.NewHistogram(prometheus.HistogramOpts{
+		Namespace: "etcd",
+		Subsystem: "snap_db",
+		Name:      "fsync_duration_seconds",
+		Help:      "The latency distributions of fsyncing .snap.db file",
+
+		// lowest bucket start of upper bound 0.001 sec (1 ms) with factor 2
+		// highest bucket start of 0.001 sec * 2^13 == 8.192 sec
+		Buckets: prometheus.ExponentialBuckets(0.001, 2, 14),
+	})
+)
+
+func init() {
+	prometheus.MustRegister(snapMarshallingSec)
+	prometheus.MustRegister(snapSaveSec)
+	prometheus.MustRegister(snapFsyncSec)
+	prometheus.MustRegister(snapDBSaveSec)
+	prometheus.MustRegister(snapDBFsyncSec)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/snap/snappb/snap.pb.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/snap/snappb/snap.pb.go
new file mode 100644
index 0000000..ff9d39c
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/snap/snappb/snap.pb.go
@@ -0,0 +1,347 @@
+// Code generated by protoc-gen-gogo. DO NOT EDIT.
+// source: snap.proto
+
+package snappb
+
+import (
+	fmt "fmt"
+	io "io"
+	math "math"
+	math_bits "math/bits"
+
+	_ "github.com/gogo/protobuf/gogoproto"
+	proto "github.com/golang/protobuf/proto"
+)
+
+// Reference imports to suppress errors if they are not otherwise used.
+var _ = proto.Marshal
+var _ = fmt.Errorf
+var _ = math.Inf
+
+// This is a compile-time assertion to ensure that this generated file
+// is compatible with the proto package it is being compiled against.
+// A compilation error at this line likely means your copy of the
+// proto package needs to be updated.
+const _ = proto.ProtoPackageIsVersion3 // please upgrade the proto package
+
+type Snapshot struct {
+	Crc                  uint32   `protobuf:"varint,1,opt,name=crc" json:"crc"`
+	Data                 []byte   `protobuf:"bytes,2,opt,name=data" json:"data,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
+}
+
+func (m *Snapshot) Reset()         { *m = Snapshot{} }
+func (m *Snapshot) String() string { return proto.CompactTextString(m) }
+func (*Snapshot) ProtoMessage()    {}
+func (*Snapshot) Descriptor() ([]byte, []int) {
+	return fileDescriptor_f2e3c045ebf84d00, []int{0}
+}
+func (m *Snapshot) XXX_Unmarshal(b []byte) error {
+	return m.Unmarshal(b)
+}
+func (m *Snapshot) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	if deterministic {
+		return xxx_messageInfo_Snapshot.Marshal(b, m, deterministic)
+	} else {
+		b = b[:cap(b)]
+		n, err := m.MarshalToSizedBuffer(b)
+		if err != nil {
+			return nil, err
+		}
+		return b[:n], nil
+	}
+}
+func (m *Snapshot) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_Snapshot.Merge(m, src)
+}
+func (m *Snapshot) XXX_Size() int {
+	return m.Size()
+}
+func (m *Snapshot) XXX_DiscardUnknown() {
+	xxx_messageInfo_Snapshot.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_Snapshot proto.InternalMessageInfo
+
+func init() {
+	proto.RegisterType((*Snapshot)(nil), "snappb.snapshot")
+}
+
+func init() { proto.RegisterFile("snap.proto", fileDescriptor_f2e3c045ebf84d00) }
+
+var fileDescriptor_f2e3c045ebf84d00 = []byte{
+	// 164 bytes of a gzipped FileDescriptorProto
+	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0xe2, 0xe2, 0x2a, 0xce, 0x4b, 0x2c,
+	0xd0, 0x2b, 0x28, 0xca, 0x2f, 0xc9, 0x17, 0x62, 0x03, 0xb1, 0x0b, 0x92, 0xa4, 0x44, 0xd2, 0xf3,
+	0xd3, 0xf3, 0xc1, 0x42, 0xfa, 0x20, 0x16, 0x44, 0x56, 0xc9, 0x8c, 0x8b, 0x03, 0x24, 0x5f, 0x9c,
+	0x91, 0x5f, 0x22, 0x24, 0xc6, 0xc5, 0x9c, 0x5c, 0x94, 0x2c, 0xc1, 0xa8, 0xc0, 0xa8, 0xc1, 0xeb,
+	0xc4, 0x72, 0xe2, 0x9e, 0x3c, 0x43, 0x10, 0x48, 0x40, 0x48, 0x88, 0x8b, 0x25, 0x25, 0xb1, 0x24,
+	0x51, 0x82, 0x49, 0x81, 0x51, 0x83, 0x27, 0x08, 0xcc, 0x76, 0xf2, 0x3a, 0xf1, 0x50, 0x8e, 0xe1,
+	0xc4, 0x23, 0x39, 0xc6, 0x0b, 0x8f, 0xe4, 0x18, 0x1f, 0x3c, 0x92, 0x63, 0x9c, 0xf1, 0x58, 0x8e,
+	0x21, 0xca, 0x24, 0x3d, 0x5f, 0x2f, 0xb5, 0x24, 0x39, 0x45, 0x2f, 0x33, 0x5f, 0x1f, 0x44, 0xeb,
+	0x17, 0xa7, 0x16, 0x95, 0xa5, 0x16, 0xe9, 0x97, 0x19, 0x83, 0xb9, 0x50, 0x5e, 0x62, 0x41, 0xa6,
+	0x3e, 0xc8, 0x52, 0x7d, 0x88, 0xcb, 0x00, 0x01, 0x00, 0x00, 0xff, 0xff, 0x8d, 0x65, 0xd9, 0x03,
+	0xae, 0x00, 0x00, 0x00,
+}
+
+func (m *Snapshot) Marshal() (dAtA []byte, err error) {
+	size := m.Size()
+	dAtA = make([]byte, size)
+	n, err := m.MarshalToSizedBuffer(dAtA[:size])
+	if err != nil {
+		return nil, err
+	}
+	return dAtA[:n], nil
+}
+
+func (m *Snapshot) MarshalTo(dAtA []byte) (int, error) {
+	size := m.Size()
+	return m.MarshalToSizedBuffer(dAtA[:size])
+}
+
+func (m *Snapshot) MarshalToSizedBuffer(dAtA []byte) (int, error) {
+	i := len(dAtA)
+	_ = i
+	var l int
+	_ = l
+	if m.XXX_unrecognized != nil {
+		i -= len(m.XXX_unrecognized)
+		copy(dAtA[i:], m.XXX_unrecognized)
+	}
+	if m.Data != nil {
+		i -= len(m.Data)
+		copy(dAtA[i:], m.Data)
+		i = encodeVarintSnap(dAtA, i, uint64(len(m.Data)))
+		i--
+		dAtA[i] = 0x12
+	}
+	i = encodeVarintSnap(dAtA, i, uint64(m.Crc))
+	i--
+	dAtA[i] = 0x8
+	return len(dAtA) - i, nil
+}
+
+func encodeVarintSnap(dAtA []byte, offset int, v uint64) int {
+	offset -= sovSnap(v)
+	base := offset
+	for v >= 1<<7 {
+		dAtA[offset] = uint8(v&0x7f | 0x80)
+		v >>= 7
+		offset++
+	}
+	dAtA[offset] = uint8(v)
+	return base
+}
+func (m *Snapshot) Size() (n int) {
+	if m == nil {
+		return 0
+	}
+	var l int
+	_ = l
+	n += 1 + sovSnap(uint64(m.Crc))
+	if m.Data != nil {
+		l = len(m.Data)
+		n += 1 + l + sovSnap(uint64(l))
+	}
+	if m.XXX_unrecognized != nil {
+		n += len(m.XXX_unrecognized)
+	}
+	return n
+}
+
+func sovSnap(x uint64) (n int) {
+	return (math_bits.Len64(x|1) + 6) / 7
+}
+func sozSnap(x uint64) (n int) {
+	return sovSnap(uint64((x << 1) ^ uint64((int64(x) >> 63))))
+}
+func (m *Snapshot) Unmarshal(dAtA []byte) error {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		preIndex := iNdEx
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return ErrIntOverflowSnap
+			}
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= uint64(b&0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		if wireType == 4 {
+			return fmt.Errorf("proto: snapshot: wiretype end group for non-group")
+		}
+		if fieldNum <= 0 {
+			return fmt.Errorf("proto: snapshot: illegal tag %d (wire type %d)", fieldNum, wire)
+		}
+		switch fieldNum {
+		case 1:
+			if wireType != 0 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Crc", wireType)
+			}
+			m.Crc = 0
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowSnap
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				m.Crc |= uint32(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+		case 2:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Data", wireType)
+			}
+			var byteLen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowSnap
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				byteLen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if byteLen < 0 {
+				return ErrInvalidLengthSnap
+			}
+			postIndex := iNdEx + byteLen
+			if postIndex < 0 {
+				return ErrInvalidLengthSnap
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.Data = append(m.Data[:0], dAtA[iNdEx:postIndex]...)
+			if m.Data == nil {
+				m.Data = []byte{}
+			}
+			iNdEx = postIndex
+		default:
+			iNdEx = preIndex
+			skippy, err := skipSnap(dAtA[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
+				return ErrInvalidLengthSnap
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.XXX_unrecognized = append(m.XXX_unrecognized, dAtA[iNdEx:iNdEx+skippy]...)
+			iNdEx += skippy
+		}
+	}
+
+	if iNdEx > l {
+		return io.ErrUnexpectedEOF
+	}
+	return nil
+}
+func skipSnap(dAtA []byte) (n int, err error) {
+	l := len(dAtA)
+	iNdEx := 0
+	depth := 0
+	for iNdEx < l {
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return 0, ErrIntOverflowSnap
+			}
+			if iNdEx >= l {
+				return 0, io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= (uint64(b) & 0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		wireType := int(wire & 0x7)
+		switch wireType {
+		case 0:
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return 0, ErrIntOverflowSnap
+				}
+				if iNdEx >= l {
+					return 0, io.ErrUnexpectedEOF
+				}
+				iNdEx++
+				if dAtA[iNdEx-1] < 0x80 {
+					break
+				}
+			}
+		case 1:
+			iNdEx += 8
+		case 2:
+			var length int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return 0, ErrIntOverflowSnap
+				}
+				if iNdEx >= l {
+					return 0, io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				length |= (int(b) & 0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if length < 0 {
+				return 0, ErrInvalidLengthSnap
+			}
+			iNdEx += length
+		case 3:
+			depth++
+		case 4:
+			if depth == 0 {
+				return 0, ErrUnexpectedEndOfGroupSnap
+			}
+			depth--
+		case 5:
+			iNdEx += 4
+		default:
+			return 0, fmt.Errorf("proto: illegal wireType %d", wireType)
+		}
+		if iNdEx < 0 {
+			return 0, ErrInvalidLengthSnap
+		}
+		if depth == 0 {
+			return iNdEx, nil
+		}
+	}
+	return 0, io.ErrUnexpectedEOF
+}
+
+var (
+	ErrInvalidLengthSnap        = fmt.Errorf("proto: negative length found during unmarshaling")
+	ErrIntOverflowSnap          = fmt.Errorf("proto: integer overflow")
+	ErrUnexpectedEndOfGroupSnap = fmt.Errorf("proto: unexpected end of group")
+)
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/snap/snappb/snap.proto b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/snap/snappb/snap.proto
new file mode 100644
index 0000000..0a74744
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/snap/snappb/snap.proto
@@ -0,0 +1,16 @@
+syntax = "proto2";
+package snappb;
+
+import "gogoproto/gogo.proto";
+
+option go_package = "go.etcd.io/etcd/server/v3/etcdserver/api/snap/snappb";
+
+option (gogoproto.marshaler_all) = true;
+option (gogoproto.sizer_all) = true;
+option (gogoproto.unmarshaler_all) = true;
+option (gogoproto.goproto_getters_all) = false;
+
+message snapshot {
+	optional uint32 crc  = 1 [(gogoproto.nullable) = false];
+	optional bytes data  = 2;
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/snap/snapshotter.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/snap/snapshotter.go
new file mode 100644
index 0000000..0de6f9b
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/snap/snapshotter.go
@@ -0,0 +1,282 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package snap
+
+import (
+	"errors"
+	"fmt"
+	"hash/crc32"
+	"os"
+	"path/filepath"
+	"sort"
+	"strconv"
+	"strings"
+	"time"
+
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/client/pkg/v3/verify"
+	pioutil "go.etcd.io/etcd/pkg/v3/ioutil"
+	"go.etcd.io/etcd/pkg/v3/pbutil"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/snap/snappb"
+	"go.etcd.io/etcd/server/v3/storage/wal/walpb"
+	"go.etcd.io/raft/v3"
+	"go.etcd.io/raft/v3/raftpb"
+)
+
+const snapSuffix = ".snap"
+
+var (
+	ErrNoSnapshot    = errors.New("snap: no available snapshot")
+	ErrEmptySnapshot = errors.New("snap: empty snapshot")
+	ErrCRCMismatch   = errors.New("snap: crc mismatch")
+	crcTable         = crc32.MakeTable(crc32.Castagnoli)
+
+	// A map of valid files that can be present in the snap folder.
+	validFiles = map[string]bool{
+		"db": true,
+	}
+)
+
+type Snapshotter struct {
+	lg  *zap.Logger
+	dir string
+}
+
+func New(lg *zap.Logger, dir string) *Snapshotter {
+	if lg == nil {
+		lg = zap.NewNop()
+	}
+	return &Snapshotter{
+		lg:  lg,
+		dir: dir,
+	}
+}
+
+func (s *Snapshotter) SaveSnap(snapshot raftpb.Snapshot) error {
+	if raft.IsEmptySnap(snapshot) {
+		return nil
+	}
+	return s.save(&snapshot)
+}
+
+func (s *Snapshotter) save(snapshot *raftpb.Snapshot) error {
+	start := time.Now()
+
+	fname := fmt.Sprintf("%016x-%016x%s", snapshot.Metadata.Term, snapshot.Metadata.Index, snapSuffix)
+	b := pbutil.MustMarshal(snapshot)
+	crc := crc32.Update(0, crcTable, b)
+	snap := snappb.Snapshot{Crc: crc, Data: b}
+	d, err := snap.Marshal()
+	if err != nil {
+		return err
+	}
+	snapMarshallingSec.Observe(time.Since(start).Seconds())
+
+	spath := filepath.Join(s.dir, fname)
+
+	fsyncStart := time.Now()
+	err = pioutil.WriteAndSyncFile(spath, d, 0o666)
+	snapFsyncSec.Observe(time.Since(fsyncStart).Seconds())
+
+	if err != nil {
+		s.lg.Warn("failed to write a snap file", zap.String("path", spath), zap.Error(err))
+		rerr := os.Remove(spath)
+		if rerr != nil {
+			s.lg.Warn("failed to remove a broken snap file", zap.String("path", spath), zap.Error(rerr))
+		}
+		return err
+	}
+
+	snapSaveSec.Observe(time.Since(start).Seconds())
+	return nil
+}
+
+// Load returns the newest snapshot.
+func (s *Snapshotter) Load() (*raftpb.Snapshot, error) {
+	return s.loadMatching(func(*raftpb.Snapshot) bool { return true })
+}
+
+// LoadNewestAvailable loads the newest snapshot available that is in walSnaps.
+func (s *Snapshotter) LoadNewestAvailable(walSnaps []walpb.Snapshot) (*raftpb.Snapshot, error) {
+	return s.loadMatching(func(snapshot *raftpb.Snapshot) bool {
+		m := snapshot.Metadata
+		for i := len(walSnaps) - 1; i >= 0; i-- {
+			if m.Term == walSnaps[i].Term && m.Index == walSnaps[i].Index {
+				return true
+			}
+		}
+		return false
+	})
+}
+
+// loadMatching returns the newest snapshot where matchFn returns true.
+func (s *Snapshotter) loadMatching(matchFn func(*raftpb.Snapshot) bool) (*raftpb.Snapshot, error) {
+	names, err := s.snapNames()
+	if err != nil {
+		return nil, err
+	}
+	var snap *raftpb.Snapshot
+	for _, name := range names {
+		if snap, err = s.loadSnap(name); err == nil && matchFn(snap) {
+			return snap, nil
+		}
+	}
+	return nil, ErrNoSnapshot
+}
+
+func (s *Snapshotter) loadSnap(name string) (*raftpb.Snapshot, error) {
+	fpath := filepath.Join(s.dir, name)
+	snap, err := Read(s.lg, fpath)
+	if err != nil {
+		brokenPath := fpath + ".broken"
+		s.lg.Warn("failed to read a snap file", zap.String("path", fpath), zap.Error(err))
+		if rerr := os.Rename(fpath, brokenPath); rerr != nil {
+			s.lg.Warn("failed to rename a broken snap file", zap.String("path", fpath), zap.String("broken-path", brokenPath), zap.Error(rerr))
+		} else {
+			s.lg.Warn("renamed to a broken snap file", zap.String("path", fpath), zap.String("broken-path", brokenPath))
+		}
+	}
+	return snap, err
+}
+
+// Read reads the snapshot named by snapname and returns the snapshot.
+func Read(lg *zap.Logger, snapname string) (*raftpb.Snapshot, error) {
+	verify.Assert(lg != nil, "the logger should not be nil")
+	b, err := os.ReadFile(snapname)
+	if err != nil {
+		lg.Warn("failed to read a snap file", zap.String("path", snapname), zap.Error(err))
+		return nil, err
+	}
+
+	if len(b) == 0 {
+		lg.Warn("failed to read empty snapshot file", zap.String("path", snapname))
+		return nil, ErrEmptySnapshot
+	}
+
+	var serializedSnap snappb.Snapshot
+	if err = serializedSnap.Unmarshal(b); err != nil {
+		lg.Warn("failed to unmarshal snappb.Snapshot", zap.String("path", snapname), zap.Error(err))
+		return nil, err
+	}
+
+	if len(serializedSnap.Data) == 0 || serializedSnap.Crc == 0 {
+		lg.Warn("failed to read empty snapshot data", zap.String("path", snapname))
+		return nil, ErrEmptySnapshot
+	}
+
+	crc := crc32.Update(0, crcTable, serializedSnap.Data)
+	if crc != serializedSnap.Crc {
+		lg.Warn("snap file is corrupt",
+			zap.String("path", snapname),
+			zap.Uint32("prev-crc", serializedSnap.Crc),
+			zap.Uint32("new-crc", crc),
+		)
+		return nil, ErrCRCMismatch
+	}
+
+	var snap raftpb.Snapshot
+	if err = snap.Unmarshal(serializedSnap.Data); err != nil {
+		lg.Warn("failed to unmarshal raftpb.Snapshot", zap.String("path", snapname), zap.Error(err))
+		return nil, err
+	}
+	return &snap, nil
+}
+
+// snapNames returns the filename of the snapshots in logical time order (from newest to oldest).
+// If there is no available snapshots, an ErrNoSnapshot will be returned.
+func (s *Snapshotter) snapNames() ([]string, error) {
+	dir, err := os.Open(s.dir)
+	if err != nil {
+		return nil, err
+	}
+	defer dir.Close()
+	names, err := dir.Readdirnames(-1)
+	if err != nil {
+		return nil, err
+	}
+	filenames, err := s.cleanupSnapdir(names)
+	if err != nil {
+		return nil, err
+	}
+	snaps := s.checkSuffix(filenames)
+	if len(snaps) == 0 {
+		return nil, ErrNoSnapshot
+	}
+	sort.Sort(sort.Reverse(sort.StringSlice(snaps)))
+	return snaps, nil
+}
+
+func (s *Snapshotter) checkSuffix(names []string) []string {
+	var snaps []string
+	for i := range names {
+		if strings.HasSuffix(names[i], snapSuffix) {
+			snaps = append(snaps, names[i])
+		} else {
+			// If we find a file which is not a snapshot then check if it's
+			// a valid file. If not throw out a warning.
+			if _, ok := validFiles[names[i]]; !ok {
+				s.lg.Warn("found unexpected non-snap file; skipping", zap.String("path", names[i]))
+			}
+		}
+	}
+	return snaps
+}
+
+// cleanupSnapdir removes any files that should not be in the snapshot directory:
+// - db.tmp prefixed files that can be orphaned by defragmentation
+func (s *Snapshotter) cleanupSnapdir(filenames []string) (names []string, err error) {
+	names = make([]string, 0, len(filenames))
+	for _, filename := range filenames {
+		if strings.HasPrefix(filename, "db.tmp") {
+			s.lg.Info("found orphaned defragmentation file; deleting", zap.String("path", filename))
+			if rmErr := os.Remove(filepath.Join(s.dir, filename)); rmErr != nil && !os.IsNotExist(rmErr) {
+				return names, fmt.Errorf("failed to remove orphaned .snap.db file %s: %w", filename, rmErr)
+			}
+		} else {
+			names = append(names, filename)
+		}
+	}
+	return names, nil
+}
+
+func (s *Snapshotter) ReleaseSnapDBs(snap raftpb.Snapshot) error {
+	dir, err := os.Open(s.dir)
+	if err != nil {
+		return err
+	}
+	defer dir.Close()
+	filenames, err := dir.Readdirnames(-1)
+	if err != nil {
+		return err
+	}
+	for _, filename := range filenames {
+		if strings.HasSuffix(filename, ".snap.db") {
+			hexIndex := strings.TrimSuffix(filepath.Base(filename), ".snap.db")
+			index, err := strconv.ParseUint(hexIndex, 16, 64)
+			if err != nil {
+				s.lg.Error("failed to parse index from filename", zap.String("path", filename), zap.String("error", err.Error()))
+				continue
+			}
+			if index < snap.Metadata.Index {
+				s.lg.Info("found orphaned .snap.db file; deleting", zap.String("path", filename))
+				if rmErr := os.Remove(filepath.Join(s.dir, filename)); rmErr != nil && !os.IsNotExist(rmErr) {
+					s.lg.Error("failed to remove orphaned .snap.db file", zap.String("path", filename), zap.String("error", rmErr.Error()))
+				}
+			}
+		}
+	}
+	return nil
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2discovery/discovery.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2discovery/discovery.go
new file mode 100644
index 0000000..00a2c7d
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2discovery/discovery.go
@@ -0,0 +1,417 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package v2discovery provides an implementation of the cluster discovery that
+// is used by etcd with v2 client.
+package v2discovery
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"math"
+	"net/http"
+	"net/url"
+	"path"
+	"sort"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/jonboulle/clockwork"
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/client/pkg/v3/transport"
+	"go.etcd.io/etcd/client/pkg/v3/types"
+	client "go.etcd.io/etcd/server/v3/internal/clientv2"
+)
+
+var (
+	ErrInvalidURL           = errors.New("discovery: invalid URL")
+	ErrBadSizeKey           = errors.New("discovery: size key is bad")
+	ErrSizeNotFound         = errors.New("discovery: size key not found")
+	ErrTokenNotFound        = errors.New("discovery: token not found")
+	ErrDuplicateID          = errors.New("discovery: found duplicate id")
+	ErrDuplicateName        = errors.New("discovery: found duplicate name")
+	ErrFullCluster          = errors.New("discovery: cluster is full")
+	ErrTooManyRetries       = errors.New("discovery: too many retries")
+	ErrBadDiscoveryEndpoint = errors.New("discovery: bad discovery endpoint")
+)
+
+var (
+	// Number of retries discovery will attempt before giving up and erroring out.
+	nRetries             = uint(math.MaxUint32)
+	maxExpoentialRetries = uint(8)
+)
+
+// JoinCluster will connect to the discovery service at the given url, and
+// register the server represented by the given id and config to the cluster
+func JoinCluster(lg *zap.Logger, durl, dproxyurl string, id types.ID, config string) (string, error) {
+	d, err := newDiscovery(lg, durl, dproxyurl, id)
+	if err != nil {
+		return "", err
+	}
+	return d.joinCluster(config)
+}
+
+// GetCluster will connect to the discovery service at the given url and
+// retrieve a string describing the cluster
+func GetCluster(lg *zap.Logger, durl, dproxyurl string) (string, error) {
+	d, err := newDiscovery(lg, durl, dproxyurl, 0)
+	if err != nil {
+		return "", err
+	}
+	return d.getCluster()
+}
+
+type discovery struct {
+	lg      *zap.Logger
+	cluster string
+	id      types.ID
+	c       client.KeysAPI
+	retries uint
+	url     *url.URL
+
+	clock clockwork.Clock
+}
+
+// newProxyFunc builds a proxy function from the given string, which should
+// represent a URL that can be used as a proxy. It performs basic
+// sanitization of the URL and returns any error encountered.
+func newProxyFunc(lg *zap.Logger, proxy string) (func(*http.Request) (*url.URL, error), error) {
+	if lg == nil {
+		lg = zap.NewNop()
+	}
+	if proxy == "" {
+		return nil, nil
+	}
+	// Do a small amount of URL sanitization to help the user
+	// Derived from net/http.ProxyFromEnvironment
+	proxyURL, err := url.Parse(proxy)
+	if err != nil || !strings.HasPrefix(proxyURL.Scheme, "http") {
+		// proxy was bogus. Try prepending "http://" to it and
+		// see if that parses correctly. If not, we ignore the
+		// error and complain about the original one
+		var err2 error
+		proxyURL, err2 = url.Parse("http://" + proxy)
+		if err2 == nil {
+			err = nil
+		}
+	}
+	if err != nil {
+		return nil, fmt.Errorf("invalid proxy address %q: %w", proxy, err)
+	}
+
+	lg.Info("running proxy with discovery", zap.String("proxy-url", proxyURL.String()))
+	return http.ProxyURL(proxyURL), nil
+}
+
+func newDiscovery(lg *zap.Logger, durl, dproxyurl string, id types.ID) (*discovery, error) {
+	if lg == nil {
+		lg = zap.NewNop()
+	}
+	u, err := url.Parse(durl)
+	if err != nil {
+		return nil, err
+	}
+	token := u.Path
+	u.Path = ""
+	pf, err := newProxyFunc(lg, dproxyurl)
+	if err != nil {
+		return nil, err
+	}
+
+	// TODO: add ResponseHeaderTimeout back when watch on discovery service writes header early
+	tr, err := transport.NewTransport(transport.TLSInfo{}, 30*time.Second)
+	if err != nil {
+		return nil, err
+	}
+	tr.Proxy = pf
+	cfg := client.Config{
+		Transport: tr,
+		Endpoints: []string{u.String()},
+	}
+	c, err := client.New(cfg)
+	if err != nil {
+		return nil, err
+	}
+	dc := client.NewKeysAPIWithPrefix(c, "")
+	return &discovery{
+		lg:      lg,
+		cluster: token,
+		c:       dc,
+		id:      id,
+		url:     u,
+		clock:   clockwork.NewRealClock(),
+	}, nil
+}
+
+func (d *discovery) joinCluster(config string) (string, error) {
+	// fast path: if the cluster is full, return the error
+	// do not need to register to the cluster in this case.
+	if _, _, _, err := d.checkCluster(); err != nil {
+		return "", err
+	}
+
+	if err := d.createSelf(config); err != nil {
+		// Fails, even on a timeout, if createSelf times out.
+		// TODO(barakmich): Retrying the same node might want to succeed here
+		// (ie, createSelf should be idempotent for discovery).
+		return "", err
+	}
+
+	nodes, size, index, err := d.checkCluster()
+	if err != nil {
+		return "", err
+	}
+
+	all, err := d.waitNodes(nodes, size, index)
+	if err != nil {
+		return "", err
+	}
+
+	return nodesToCluster(all, size)
+}
+
+func (d *discovery) getCluster() (string, error) {
+	nodes, size, index, err := d.checkCluster()
+	if err != nil {
+		if errors.Is(err, ErrFullCluster) {
+			return nodesToCluster(nodes, size)
+		}
+		return "", err
+	}
+
+	all, err := d.waitNodes(nodes, size, index)
+	if err != nil {
+		return "", err
+	}
+	return nodesToCluster(all, size)
+}
+
+func (d *discovery) createSelf(contents string) error {
+	ctx, cancel := context.WithTimeout(context.Background(), client.DefaultRequestTimeout)
+	resp, err := d.c.Create(ctx, d.selfKey(), contents)
+	cancel()
+	if err != nil {
+		var eerr client.Error
+		if errors.As(err, &eerr) && eerr.Code == client.ErrorCodeNodeExist {
+			return ErrDuplicateID
+		}
+		return err
+	}
+
+	// ensure self appears on the server we connected to
+	w := d.c.Watcher(d.selfKey(), &client.WatcherOptions{AfterIndex: resp.Node.CreatedIndex - 1})
+	_, err = w.Next(context.Background())
+	return err
+}
+
+func (d *discovery) checkCluster() ([]*client.Node, uint64, uint64, error) {
+	configKey := path.Join("/", d.cluster, "_config")
+	ctx, cancel := context.WithTimeout(context.Background(), client.DefaultRequestTimeout)
+	// find cluster size
+	resp, err := d.c.Get(ctx, path.Join(configKey, "size"), nil)
+	cancel()
+	if err != nil {
+		var eerr *client.Error
+		if errors.As(err, &eerr) && eerr.Code == client.ErrorCodeKeyNotFound {
+			return nil, 0, 0, ErrSizeNotFound
+		}
+		if errors.Is(err, client.ErrInvalidJSON) {
+			return nil, 0, 0, ErrBadDiscoveryEndpoint
+		}
+		var ce *client.ClusterError
+		if errors.As(err, &ce) {
+			d.lg.Warn(
+				"failed to get from discovery server",
+				zap.String("discovery-url", d.url.String()),
+				zap.String("path", path.Join(configKey, "size")),
+				zap.Error(err),
+				zap.String("err-detail", ce.Detail()),
+			)
+			return d.checkClusterRetry()
+		}
+		return nil, 0, 0, err
+	}
+	size, err := strconv.ParseUint(resp.Node.Value, 10, 0)
+	if err != nil {
+		return nil, 0, 0, ErrBadSizeKey
+	}
+
+	ctx, cancel = context.WithTimeout(context.Background(), client.DefaultRequestTimeout)
+	resp, err = d.c.Get(ctx, d.cluster, nil)
+	cancel()
+	if err != nil {
+		var ce *client.ClusterError
+		if errors.As(err, &ce) {
+			d.lg.Warn(
+				"failed to get from discovery server",
+				zap.String("discovery-url", d.url.String()),
+				zap.String("path", d.cluster),
+				zap.Error(err),
+				zap.String("err-detail", ce.Detail()),
+			)
+			return d.checkClusterRetry()
+		}
+		return nil, 0, 0, err
+	}
+	var nodes []*client.Node
+	// append non-config keys to nodes
+	for _, n := range resp.Node.Nodes {
+		if path.Base(n.Key) != path.Base(configKey) {
+			nodes = append(nodes, n)
+		}
+	}
+
+	snodes := sortableNodes{nodes}
+	sort.Sort(snodes)
+
+	// find self position
+	for i := range nodes {
+		if path.Base(nodes[i].Key) == path.Base(d.selfKey()) {
+			break
+		}
+		if uint64(i) >= size-1 {
+			return nodes[:size], size, resp.Index, ErrFullCluster
+		}
+	}
+	return nodes, size, resp.Index, nil
+}
+
+func (d *discovery) logAndBackoffForRetry(step string) {
+	d.retries++
+	// logAndBackoffForRetry stops exponential backoff when the retries are more than maxExpoentialRetries and is set to a constant backoff afterward.
+	retries := d.retries
+	if retries > maxExpoentialRetries {
+		retries = maxExpoentialRetries
+	}
+	retryTimeInSecond := time.Duration(0x1<<retries) * time.Second
+	d.lg.Info(
+		"retry connecting to discovery service",
+		zap.String("url", d.url.String()),
+		zap.String("reason", step),
+		zap.Duration("backoff", retryTimeInSecond),
+	)
+	d.clock.Sleep(retryTimeInSecond)
+}
+
+func (d *discovery) checkClusterRetry() ([]*client.Node, uint64, uint64, error) {
+	if d.retries < nRetries {
+		d.logAndBackoffForRetry("cluster status check")
+		return d.checkCluster()
+	}
+	return nil, 0, 0, ErrTooManyRetries
+}
+
+func (d *discovery) waitNodesRetry() ([]*client.Node, error) {
+	if d.retries < nRetries {
+		d.logAndBackoffForRetry("waiting for other nodes")
+		nodes, n, index, err := d.checkCluster()
+		if err != nil {
+			return nil, err
+		}
+		return d.waitNodes(nodes, n, index)
+	}
+	return nil, ErrTooManyRetries
+}
+
+func (d *discovery) waitNodes(nodes []*client.Node, size uint64, index uint64) ([]*client.Node, error) {
+	if uint64(len(nodes)) > size {
+		nodes = nodes[:size]
+	}
+	// watch from the next index
+	w := d.c.Watcher(d.cluster, &client.WatcherOptions{AfterIndex: index, Recursive: true})
+	all := make([]*client.Node, len(nodes))
+	copy(all, nodes)
+	for _, n := range all {
+		if path.Base(n.Key) == path.Base(d.selfKey()) {
+			d.lg.Info(
+				"found self from discovery server",
+				zap.String("discovery-url", d.url.String()),
+				zap.String("self", path.Base(d.selfKey())),
+			)
+		} else {
+			d.lg.Info(
+				"found peer from discovery server",
+				zap.String("discovery-url", d.url.String()),
+				zap.String("peer", path.Base(n.Key)),
+			)
+		}
+	}
+
+	// wait for others
+	for uint64(len(all)) < size {
+		d.lg.Info(
+			"found peers from discovery server; waiting for more",
+			zap.String("discovery-url", d.url.String()),
+			zap.Int("found-peers", len(all)),
+			zap.Int("needed-peers", int(size-uint64(len(all)))),
+		)
+		resp, err := w.Next(context.Background())
+		if err != nil {
+			var ce *client.ClusterError
+			if errors.As(err, &ce) {
+				d.lg.Warn(
+					"error while waiting for peers",
+					zap.String("discovery-url", d.url.String()),
+					zap.Error(err),
+					zap.String("err-detail", ce.Detail()),
+				)
+				return d.waitNodesRetry()
+			}
+			return nil, err
+		}
+		d.lg.Info(
+			"found peer from discovery server",
+			zap.String("discovery-url", d.url.String()),
+			zap.String("peer", path.Base(resp.Node.Key)),
+		)
+		all = append(all, resp.Node)
+	}
+	d.lg.Info(
+		"found all needed peers from discovery server",
+		zap.String("discovery-url", d.url.String()),
+		zap.Int("found-peers", len(all)),
+	)
+	return all, nil
+}
+
+func (d *discovery) selfKey() string {
+	return path.Join("/", d.cluster, d.id.String())
+}
+
+func nodesToCluster(ns []*client.Node, size uint64) (string, error) {
+	s := make([]string, len(ns))
+	for i, n := range ns {
+		s[i] = n.Value
+	}
+	us := strings.Join(s, ",")
+	m, err := types.NewURLsMap(us)
+	if err != nil {
+		return us, ErrInvalidURL
+	}
+	if uint64(m.Len()) != size {
+		return us, ErrDuplicateName
+	}
+	return us, nil
+}
+
+type sortableNodes struct{ Nodes []*client.Node }
+
+func (ns sortableNodes) Len() int { return len(ns.Nodes) }
+func (ns sortableNodes) Less(i, j int) bool {
+	return ns.Nodes[i].CreatedIndex < ns.Nodes[j].CreatedIndex
+}
+func (ns sortableNodes) Swap(i, j int) { ns.Nodes[i], ns.Nodes[j] = ns.Nodes[j], ns.Nodes[i] }
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2error/error.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2error/error.go
new file mode 100644
index 0000000..168796e
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2error/error.go
@@ -0,0 +1,161 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package v2error describes errors in etcd project. When any change happens,
+// https://github.com/etcd-io/website/blob/main/content/docs/v2/errorcode.md
+// needs to be updated correspondingly.
+// To be deprecated in favor of v3 APIs.
+package v2error
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+)
+
+var errors = map[int]string{
+	// command related errors
+	EcodeKeyNotFound:      "Key not found",
+	EcodeTestFailed:       "Compare failed", // test and set
+	EcodeNotFile:          "Not a file",
+	ecodeNoMorePeer:       "Reached the max number of peers in the cluster",
+	EcodeNotDir:           "Not a directory",
+	EcodeNodeExist:        "Key already exists", // create
+	ecodeKeyIsPreserved:   "The prefix of given key is a keyword in etcd",
+	EcodeRootROnly:        "Root is read only",
+	EcodeDirNotEmpty:      "Directory not empty",
+	ecodeExistingPeerAddr: "Peer address has existed",
+	EcodeUnauthorized:     "The request requires user authentication",
+
+	// Post form related errors
+	ecodeValueRequired:        "Value is Required in POST form",
+	EcodePrevValueRequired:    "PrevValue is Required in POST form",
+	EcodeTTLNaN:               "The given TTL in POST form is not a number",
+	EcodeIndexNaN:             "The given index in POST form is not a number",
+	ecodeValueOrTTLRequired:   "Value or TTL is required in POST form",
+	ecodeTimeoutNaN:           "The given timeout in POST form is not a number",
+	ecodeNameRequired:         "Name is required in POST form",
+	ecodeIndexOrValueRequired: "Index or value is required",
+	ecodeIndexValueMutex:      "Index and value cannot both be specified",
+	EcodeInvalidField:         "Invalid field",
+	EcodeInvalidForm:          "Invalid POST form",
+	EcodeRefreshValue:         "Value provided on refresh",
+	EcodeRefreshTTLRequired:   "A TTL must be provided on refresh",
+
+	// raft related errors
+	EcodeRaftInternal: "Raft Internal Error",
+	EcodeLeaderElect:  "During Leader Election",
+
+	// etcd related errors
+	EcodeWatcherCleared:     "watcher is cleared due to etcd recovery",
+	EcodeEventIndexCleared:  "The event in requested index is outdated and cleared",
+	ecodeStandbyInternal:    "Standby Internal Error",
+	ecodeInvalidActiveSize:  "Invalid active size",
+	ecodeInvalidRemoveDelay: "Standby remove delay",
+
+	// client related errors
+	ecodeClientInternal: "Client Internal Error",
+}
+
+var errorStatus = map[int]int{
+	EcodeKeyNotFound:  http.StatusNotFound,
+	EcodeNotFile:      http.StatusForbidden,
+	EcodeDirNotEmpty:  http.StatusForbidden,
+	EcodeUnauthorized: http.StatusUnauthorized,
+	EcodeTestFailed:   http.StatusPreconditionFailed,
+	EcodeNodeExist:    http.StatusPreconditionFailed,
+	EcodeRaftInternal: http.StatusInternalServerError,
+	EcodeLeaderElect:  http.StatusInternalServerError,
+}
+
+const (
+	EcodeKeyNotFound      = 100
+	EcodeTestFailed       = 101
+	EcodeNotFile          = 102
+	ecodeNoMorePeer       = 103
+	EcodeNotDir           = 104
+	EcodeNodeExist        = 105
+	ecodeKeyIsPreserved   = 106
+	EcodeRootROnly        = 107
+	EcodeDirNotEmpty      = 108
+	ecodeExistingPeerAddr = 109
+	EcodeUnauthorized     = 110
+
+	ecodeValueRequired        = 200
+	EcodePrevValueRequired    = 201
+	EcodeTTLNaN               = 202
+	EcodeIndexNaN             = 203
+	ecodeValueOrTTLRequired   = 204
+	ecodeTimeoutNaN           = 205
+	ecodeNameRequired         = 206
+	ecodeIndexOrValueRequired = 207
+	ecodeIndexValueMutex      = 208
+	EcodeInvalidField         = 209
+	EcodeInvalidForm          = 210
+	EcodeRefreshValue         = 211
+	EcodeRefreshTTLRequired   = 212
+
+	EcodeRaftInternal = 300
+	EcodeLeaderElect  = 301
+
+	EcodeWatcherCleared     = 400
+	EcodeEventIndexCleared  = 401
+	ecodeStandbyInternal    = 402
+	ecodeInvalidActiveSize  = 403
+	ecodeInvalidRemoveDelay = 404
+
+	ecodeClientInternal = 500
+)
+
+type Error struct {
+	ErrorCode int    `json:"errorCode"`
+	Message   string `json:"message"`
+	Cause     string `json:"cause,omitempty"`
+	Index     uint64 `json:"index"`
+}
+
+func NewError(errorCode int, cause string, index uint64) *Error {
+	return &Error{
+		ErrorCode: errorCode,
+		Message:   errors[errorCode],
+		Cause:     cause,
+		Index:     index,
+	}
+}
+
+// Error is for the error interface
+func (e Error) Error() string {
+	return e.Message + " (" + e.Cause + ")"
+}
+
+func (e Error) toJSONString() string {
+	b, _ := json.Marshal(e)
+	return string(b)
+}
+
+func (e Error) StatusCode() int {
+	status, ok := errorStatus[e.ErrorCode]
+	if !ok {
+		status = http.StatusBadRequest
+	}
+	return status
+}
+
+func (e Error) WriteTo(w http.ResponseWriter) error {
+	w.Header().Add("X-Etcd-Index", fmt.Sprint(e.Index))
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(e.StatusCode())
+	_, err := w.Write([]byte(e.toJSONString() + "\n"))
+	return err
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2stats/leader.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2stats/leader.go
new file mode 100644
index 0000000..f17cecc
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2stats/leader.go
@@ -0,0 +1,135 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v2stats
+
+import (
+	"encoding/json"
+	"math"
+	"sync"
+	"time"
+
+	"go.uber.org/zap"
+)
+
+// LeaderStats is used by the leader in an etcd cluster, and encapsulates
+// statistics about communication with its followers
+type LeaderStats struct {
+	lg *zap.Logger
+	leaderStats
+	sync.Mutex
+}
+
+type leaderStats struct {
+	// Leader is the ID of the leader in the etcd cluster.
+	// TODO(jonboulle): clarify that these are IDs, not names
+	Leader    string                    `json:"leader"`
+	Followers map[string]*FollowerStats `json:"followers"`
+}
+
+// NewLeaderStats generates a new LeaderStats with the given id as leader
+func NewLeaderStats(lg *zap.Logger, id string) *LeaderStats {
+	if lg == nil {
+		lg = zap.NewNop()
+	}
+	return &LeaderStats{
+		lg: lg,
+		leaderStats: leaderStats{
+			Leader:    id,
+			Followers: make(map[string]*FollowerStats),
+		},
+	}
+}
+
+func (ls *LeaderStats) JSON() []byte {
+	ls.Lock()
+	stats := ls.leaderStats
+	ls.Unlock()
+	b, err := json.Marshal(stats)
+	// TODO(jonboulle): appropriate error handling?
+	if err != nil {
+		ls.lg.Error("failed to marshal leader stats", zap.Error(err))
+	}
+	return b
+}
+
+func (ls *LeaderStats) Follower(name string) *FollowerStats {
+	ls.Lock()
+	defer ls.Unlock()
+	fs, ok := ls.Followers[name]
+	if !ok {
+		fs = &FollowerStats{}
+		fs.Latency.Minimum = 1 << 63
+		ls.Followers[name] = fs
+	}
+	return fs
+}
+
+// FollowerStats encapsulates various statistics about a follower in an etcd cluster
+type FollowerStats struct {
+	Latency LatencyStats `json:"latency"`
+	Counts  CountsStats  `json:"counts"`
+
+	sync.Mutex
+}
+
+// LatencyStats encapsulates latency statistics.
+type LatencyStats struct {
+	Current           float64 `json:"current"`
+	Average           float64 `json:"average"`
+	averageSquare     float64
+	StandardDeviation float64 `json:"standardDeviation"`
+	Minimum           float64 `json:"minimum"`
+	Maximum           float64 `json:"maximum"`
+}
+
+// CountsStats encapsulates raft statistics.
+type CountsStats struct {
+	Fail    uint64 `json:"fail"`
+	Success uint64 `json:"success"`
+}
+
+// Succ updates the FollowerStats with a successful send
+func (fs *FollowerStats) Succ(d time.Duration) {
+	fs.Lock()
+	defer fs.Unlock()
+
+	total := float64(fs.Counts.Success) * fs.Latency.Average
+	totalSquare := float64(fs.Counts.Success) * fs.Latency.averageSquare
+
+	fs.Counts.Success++
+
+	fs.Latency.Current = float64(d) / (1000000.0)
+
+	if fs.Latency.Current > fs.Latency.Maximum {
+		fs.Latency.Maximum = fs.Latency.Current
+	}
+
+	if fs.Latency.Current < fs.Latency.Minimum {
+		fs.Latency.Minimum = fs.Latency.Current
+	}
+
+	fs.Latency.Average = (total + fs.Latency.Current) / float64(fs.Counts.Success)
+	fs.Latency.averageSquare = (totalSquare + fs.Latency.Current*fs.Latency.Current) / float64(fs.Counts.Success)
+
+	// sdv = sqrt(avg(x^2) - avg(x)^2)
+	fs.Latency.StandardDeviation = math.Sqrt(fs.Latency.averageSquare - fs.Latency.Average*fs.Latency.Average)
+}
+
+// Fail updates the FollowerStats with an unsuccessful send
+func (fs *FollowerStats) Fail() {
+	fs.Lock()
+	defer fs.Unlock()
+	fs.Counts.Fail++
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2stats/queue.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2stats/queue.go
new file mode 100644
index 0000000..e16cec1
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2stats/queue.go
@@ -0,0 +1,109 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v2stats
+
+import (
+	"sync"
+	"time"
+)
+
+const (
+	queueCapacity = 200
+)
+
+// RequestStats represent the stats for a request.
+// It encapsulates the sending time and the size of the request.
+type RequestStats struct {
+	SendingTime time.Time
+	Size        int
+}
+
+type statsQueue struct {
+	items        [queueCapacity]*RequestStats
+	size         int
+	front        int
+	back         int
+	totalReqSize int
+	rwl          sync.RWMutex
+}
+
+func (q *statsQueue) Len() int {
+	return q.size
+}
+
+func (q *statsQueue) ReqSize() int {
+	return q.totalReqSize
+}
+
+// FrontAndBack gets the front and back elements in the queue
+// We must grab front and back together with the protection of the lock
+func (q *statsQueue) frontAndBack() (*RequestStats, *RequestStats) {
+	q.rwl.RLock()
+	defer q.rwl.RUnlock()
+	if q.size != 0 {
+		return q.items[q.front], q.items[q.back]
+	}
+	return nil, nil
+}
+
+// Insert function insert a RequestStats into the queue and update the records
+func (q *statsQueue) Insert(p *RequestStats) {
+	q.rwl.Lock()
+	defer q.rwl.Unlock()
+
+	q.back = (q.back + 1) % queueCapacity
+
+	if q.size == queueCapacity { // dequeue
+		q.totalReqSize -= q.items[q.front].Size
+		q.front = (q.back + 1) % queueCapacity
+	} else {
+		q.size++
+	}
+
+	q.items[q.back] = p
+	q.totalReqSize += q.items[q.back].Size
+}
+
+// Rate function returns the package rate and byte rate
+func (q *statsQueue) Rate() (float64, float64) {
+	front, back := q.frontAndBack()
+
+	if front == nil || back == nil {
+		return 0, 0
+	}
+
+	if time.Since(back.SendingTime) > time.Second {
+		q.Clear()
+		return 0, 0
+	}
+
+	sampleDuration := back.SendingTime.Sub(front.SendingTime)
+
+	pr := float64(q.Len()) / float64(sampleDuration) * float64(time.Second)
+
+	br := float64(q.ReqSize()) / float64(sampleDuration) * float64(time.Second)
+
+	return pr, br
+}
+
+// Clear function clear up the statsQueue
+func (q *statsQueue) Clear() {
+	q.rwl.Lock()
+	defer q.rwl.Unlock()
+	q.back = -1
+	q.front = 0
+	q.size = 0
+	q.totalReqSize = 0
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2stats/server.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2stats/server.go
new file mode 100644
index 0000000..e8d218a
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2stats/server.go
@@ -0,0 +1,142 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v2stats
+
+import (
+	"encoding/json"
+	"log"
+	"sync"
+	"time"
+
+	"go.etcd.io/raft/v3"
+)
+
+// ServerStats encapsulates various statistics about an EtcdServer and its
+// communication with other members of the cluster
+type ServerStats struct {
+	serverStats
+	sync.Mutex
+}
+
+func NewServerStats(name, id string) *ServerStats {
+	ss := &ServerStats{
+		serverStats: serverStats{
+			Name: name,
+			ID:   id,
+		},
+	}
+	now := time.Now()
+	ss.StartTime = now
+	ss.LeaderInfo.StartTime = now
+	ss.sendRateQueue = &statsQueue{back: -1}
+	ss.recvRateQueue = &statsQueue{back: -1}
+	return ss
+}
+
+type serverStats struct {
+	Name string `json:"name"`
+	// ID is the raft ID of the node.
+	// TODO(jonboulle): use ID instead of name?
+	ID        string         `json:"id"`
+	State     raft.StateType `json:"state"`
+	StartTime time.Time      `json:"startTime"`
+
+	LeaderInfo struct {
+		Name      string    `json:"leader"`
+		Uptime    string    `json:"uptime"`
+		StartTime time.Time `json:"startTime"`
+	} `json:"leaderInfo"`
+
+	RecvAppendRequestCnt uint64  `json:"recvAppendRequestCnt"`
+	RecvingPkgRate       float64 `json:"recvPkgRate,omitempty"`
+	RecvingBandwidthRate float64 `json:"recvBandwidthRate,omitempty"`
+
+	SendAppendRequestCnt uint64  `json:"sendAppendRequestCnt"`
+	SendingPkgRate       float64 `json:"sendPkgRate,omitempty"`
+	SendingBandwidthRate float64 `json:"sendBandwidthRate,omitempty"`
+
+	sendRateQueue *statsQueue
+	recvRateQueue *statsQueue
+}
+
+func (ss *ServerStats) JSON() []byte {
+	ss.Lock()
+	stats := ss.serverStats
+	stats.SendingPkgRate, stats.SendingBandwidthRate = stats.sendRateQueue.Rate()
+	stats.RecvingPkgRate, stats.RecvingBandwidthRate = stats.recvRateQueue.Rate()
+	stats.LeaderInfo.Uptime = time.Since(stats.LeaderInfo.StartTime).String()
+	ss.Unlock()
+	b, err := json.Marshal(stats)
+	// TODO(jonboulle): appropriate error handling?
+	if err != nil {
+		log.Printf("stats: error marshalling server stats: %v", err)
+	}
+	return b
+}
+
+// RecvAppendReq updates the ServerStats in response to an AppendRequest
+// from the given leader being received
+func (ss *ServerStats) RecvAppendReq(leader string, reqSize int) {
+	ss.Lock()
+	defer ss.Unlock()
+
+	now := time.Now()
+
+	ss.State = raft.StateFollower
+	if leader != ss.LeaderInfo.Name {
+		ss.LeaderInfo.Name = leader
+		ss.LeaderInfo.StartTime = now
+	}
+
+	ss.recvRateQueue.Insert(
+		&RequestStats{
+			SendingTime: now,
+			Size:        reqSize,
+		},
+	)
+	ss.RecvAppendRequestCnt++
+}
+
+// SendAppendReq updates the ServerStats in response to an AppendRequest
+// being sent by this server
+func (ss *ServerStats) SendAppendReq(reqSize int) {
+	ss.Lock()
+	defer ss.Unlock()
+
+	ss.becomeLeader()
+
+	ss.sendRateQueue.Insert(
+		&RequestStats{
+			SendingTime: time.Now(),
+			Size:        reqSize,
+		},
+	)
+
+	ss.SendAppendRequestCnt++
+}
+
+func (ss *ServerStats) BecomeLeader() {
+	ss.Lock()
+	defer ss.Unlock()
+	ss.becomeLeader()
+}
+
+func (ss *ServerStats) becomeLeader() {
+	if ss.State != raft.StateLeader {
+		ss.State = raft.StateLeader
+		ss.LeaderInfo.Name = ss.ID
+		ss.LeaderInfo.StartTime = time.Now()
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/doc.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/doc.go
new file mode 100644
index 0000000..1933e4c
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/doc.go
@@ -0,0 +1,17 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package v2store defines etcd's in-memory key/value store in v2 API.
+// To be deprecated in favor of v3 storage.
+package v2store
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/event.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/event.go
new file mode 100644
index 0000000..33e9017
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/event.go
@@ -0,0 +1,71 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v2store
+
+const (
+	Get              = "get"
+	Create           = "create"
+	Set              = "set"
+	Update           = "update"
+	Delete           = "delete"
+	CompareAndSwap   = "compareAndSwap"
+	CompareAndDelete = "compareAndDelete"
+	Expire           = "expire"
+)
+
+type Event struct {
+	Action    string      `json:"action"`
+	Node      *NodeExtern `json:"node,omitempty"`
+	PrevNode  *NodeExtern `json:"prevNode,omitempty"`
+	EtcdIndex uint64      `json:"-"`
+	Refresh   bool        `json:"refresh,omitempty"`
+}
+
+func newEvent(action string, key string, modifiedIndex, createdIndex uint64) *Event {
+	n := &NodeExtern{
+		Key:           key,
+		ModifiedIndex: modifiedIndex,
+		CreatedIndex:  createdIndex,
+	}
+
+	return &Event{
+		Action: action,
+		Node:   n,
+	}
+}
+
+func (e *Event) IsCreated() bool {
+	if e.Action == Create {
+		return true
+	}
+	return e.Action == Set && e.PrevNode == nil
+}
+
+func (e *Event) Index() uint64 {
+	return e.Node.ModifiedIndex
+}
+
+func (e *Event) Clone() *Event {
+	return &Event{
+		Action:    e.Action,
+		EtcdIndex: e.EtcdIndex,
+		Node:      e.Node.Clone(),
+		PrevNode:  e.PrevNode.Clone(),
+	}
+}
+
+func (e *Event) SetRefresh() {
+	e.Refresh = true
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/event_history.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/event_history.go
new file mode 100644
index 0000000..11c8b01
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/event_history.go
@@ -0,0 +1,128 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v2store
+
+import (
+	"fmt"
+	"path"
+	"strings"
+	"sync"
+
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v2error"
+)
+
+type EventHistory struct {
+	Queue      eventQueue
+	StartIndex uint64
+	LastIndex  uint64
+	rwl        sync.RWMutex
+}
+
+func newEventHistory(capacity int) *EventHistory {
+	return &EventHistory{
+		Queue: eventQueue{
+			Capacity: capacity,
+			Events:   make([]*Event, capacity),
+		},
+	}
+}
+
+// addEvent function adds event into the eventHistory
+func (eh *EventHistory) addEvent(e *Event) *Event {
+	eh.rwl.Lock()
+	defer eh.rwl.Unlock()
+
+	eh.Queue.insert(e)
+
+	eh.LastIndex = e.Index()
+
+	eh.StartIndex = eh.Queue.Events[eh.Queue.Front].Index()
+
+	return e
+}
+
+// scan enumerates events from the index history and stops at the first point
+// where the key matches.
+func (eh *EventHistory) scan(key string, recursive bool, index uint64) (*Event, *v2error.Error) {
+	eh.rwl.RLock()
+	defer eh.rwl.RUnlock()
+
+	// index should be after the event history's StartIndex
+	if index < eh.StartIndex {
+		return nil,
+			v2error.NewError(v2error.EcodeEventIndexCleared,
+				fmt.Sprintf("the requested history has been cleared [%v/%v]",
+					eh.StartIndex, index), 0)
+	}
+
+	// the index should come before the size of the queue minus the duplicate count
+	if index > eh.LastIndex { // future index
+		return nil, nil
+	}
+
+	offset := index - eh.StartIndex
+	i := (eh.Queue.Front + int(offset)) % eh.Queue.Capacity
+
+	for {
+		e := eh.Queue.Events[i]
+
+		if !e.Refresh {
+			ok := e.Node.Key == key
+
+			if recursive {
+				// add tailing slash
+				nkey := path.Clean(key)
+				if nkey[len(nkey)-1] != '/' {
+					nkey = nkey + "/"
+				}
+
+				ok = ok || strings.HasPrefix(e.Node.Key, nkey)
+			}
+
+			if (e.Action == Delete || e.Action == Expire) && e.PrevNode != nil && e.PrevNode.Dir {
+				ok = ok || strings.HasPrefix(key, e.PrevNode.Key)
+			}
+
+			if ok {
+				return e, nil
+			}
+		}
+
+		i = (i + 1) % eh.Queue.Capacity
+
+		if i == eh.Queue.Back {
+			return nil, nil
+		}
+	}
+}
+
+// clone will be protected by a stop-world lock
+// do not need to obtain internal lock
+func (eh *EventHistory) clone() *EventHistory {
+	clonedQueue := eventQueue{
+		Capacity: eh.Queue.Capacity,
+		Events:   make([]*Event, eh.Queue.Capacity),
+		Size:     eh.Queue.Size,
+		Front:    eh.Queue.Front,
+		Back:     eh.Queue.Back,
+	}
+
+	copy(clonedQueue.Events, eh.Queue.Events)
+	return &EventHistory{
+		StartIndex: eh.StartIndex,
+		Queue:      clonedQueue,
+		LastIndex:  eh.LastIndex,
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/event_queue.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/event_queue.go
new file mode 100644
index 0000000..aa2a645
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/event_queue.go
@@ -0,0 +1,34 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v2store
+
+type eventQueue struct {
+	Events   []*Event
+	Size     int
+	Front    int
+	Back     int
+	Capacity int
+}
+
+func (eq *eventQueue) insert(e *Event) {
+	eq.Events[eq.Back] = e
+	eq.Back = (eq.Back + 1) % eq.Capacity
+
+	if eq.Size == eq.Capacity { // dequeue
+		eq.Front = (eq.Front + 1) % eq.Capacity
+	} else {
+		eq.Size++
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/metrics.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/metrics.go
new file mode 100644
index 0000000..943457b
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/metrics.go
@@ -0,0 +1,141 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v2store
+
+import "github.com/prometheus/client_golang/prometheus"
+
+// Set of raw Prometheus metrics.
+// Labels
+// * action = declared in event.go
+// * outcome = Outcome
+// Do not increment directly, use Report* methods.
+var (
+	readCounter = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: "etcd_debugging",
+			Subsystem: "store",
+			Name:      "reads_total",
+			Help:      "Total number of reads action by (get/getRecursive), local to this member.",
+		},
+		[]string{"action"},
+	)
+
+	writeCounter = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: "etcd_debugging",
+			Subsystem: "store",
+			Name:      "writes_total",
+			Help:      "Total number of writes (e.g. set/compareAndDelete) seen by this member.",
+		},
+		[]string{"action"},
+	)
+
+	readFailedCounter = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: "etcd_debugging",
+			Subsystem: "store",
+			Name:      "reads_failed_total",
+			Help:      "Failed read actions by (get/getRecursive), local to this member.",
+		},
+		[]string{"action"},
+	)
+
+	writeFailedCounter = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: "etcd_debugging",
+			Subsystem: "store",
+			Name:      "writes_failed_total",
+			Help:      "Failed write actions (e.g. set/compareAndDelete), seen by this member.",
+		},
+		[]string{"action"},
+	)
+
+	expireCounter = prometheus.NewCounter(
+		prometheus.CounterOpts{
+			Namespace: "etcd_debugging",
+			Subsystem: "store",
+			Name:      "expires_total",
+			Help:      "Total number of expired keys.",
+		},
+	)
+
+	watchRequests = prometheus.NewCounter(
+		prometheus.CounterOpts{
+			Namespace: "etcd_debugging",
+			Subsystem: "store",
+			Name:      "watch_requests_total",
+			Help:      "Total number of incoming watch requests (new or reestablished).",
+		},
+	)
+
+	watcherCount = prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Namespace: "etcd_debugging",
+			Subsystem: "store",
+			Name:      "watchers",
+			Help:      "Count of currently active watchers.",
+		},
+	)
+)
+
+const (
+	GetRecursive = "getRecursive"
+)
+
+func init() {
+	if prometheus.Register(readCounter) != nil {
+		// Tests will try to double register since the tests use both
+		// store and store_test packages; ignore second attempts.
+		return
+	}
+	prometheus.MustRegister(writeCounter)
+	prometheus.MustRegister(expireCounter)
+	prometheus.MustRegister(watchRequests)
+	prometheus.MustRegister(watcherCount)
+}
+
+func reportReadSuccess(readAction string) {
+	readCounter.WithLabelValues(readAction).Inc()
+}
+
+func reportReadFailure(readAction string) {
+	readCounter.WithLabelValues(readAction).Inc()
+	readFailedCounter.WithLabelValues(readAction).Inc()
+}
+
+func reportWriteSuccess(writeAction string) {
+	writeCounter.WithLabelValues(writeAction).Inc()
+}
+
+func reportWriteFailure(writeAction string) {
+	writeCounter.WithLabelValues(writeAction).Inc()
+	writeFailedCounter.WithLabelValues(writeAction).Inc()
+}
+
+func reportExpiredKey() {
+	expireCounter.Inc()
+}
+
+func reportWatchRequest() {
+	watchRequests.Inc()
+}
+
+func reportWatcherAdded() {
+	watcherCount.Inc()
+}
+
+func reportWatcherRemoved() {
+	watcherCount.Dec()
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/node.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/node.go
new file mode 100644
index 0000000..7e5c3e8
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/node.go
@@ -0,0 +1,395 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v2store
+
+import (
+	"path"
+	"sort"
+	"time"
+
+	"github.com/jonboulle/clockwork"
+
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v2error"
+)
+
+// explanations of Compare function result
+const (
+	CompareMatch = iota
+	CompareIndexNotMatch
+	CompareValueNotMatch
+	CompareNotMatch
+)
+
+var Permanent time.Time
+
+// node is the basic element in the store system.
+// A key-value pair will have a string value
+// A directory will have a children map
+type node struct {
+	Path string
+
+	CreatedIndex  uint64
+	ModifiedIndex uint64
+
+	Parent *node `json:"-"` // should not encode this field! avoid circular dependency.
+
+	ExpireTime time.Time
+	Value      string           // for key-value pair
+	Children   map[string]*node // for directory
+
+	// A reference to the store this node is attached to.
+	store *store
+}
+
+// newKV creates a Key-Value pair
+func newKV(store *store, nodePath string, value string, createdIndex uint64, parent *node, expireTime time.Time) *node {
+	return &node{
+		Path:          nodePath,
+		CreatedIndex:  createdIndex,
+		ModifiedIndex: createdIndex,
+		Parent:        parent,
+		store:         store,
+		ExpireTime:    expireTime,
+		Value:         value,
+	}
+}
+
+// newDir creates a directory
+func newDir(store *store, nodePath string, createdIndex uint64, parent *node, expireTime time.Time) *node {
+	return &node{
+		Path:          nodePath,
+		CreatedIndex:  createdIndex,
+		ModifiedIndex: createdIndex,
+		Parent:        parent,
+		ExpireTime:    expireTime,
+		Children:      make(map[string]*node),
+		store:         store,
+	}
+}
+
+// IsHidden function checks if the node is a hidden node. A hidden node
+// will begin with '_'
+// A hidden node will not be shown via get command under a directory
+// For example if we have /foo/_hidden and /foo/notHidden, get "/foo"
+// will only return /foo/notHidden
+func (n *node) IsHidden() bool {
+	_, name := path.Split(n.Path)
+
+	return name[0] == '_'
+}
+
+// IsPermanent function checks if the node is a permanent one.
+func (n *node) IsPermanent() bool {
+	// we use a uninitialized time.Time to indicate the node is a
+	// permanent one.
+	// the uninitialized time.Time should equal zero.
+	return n.ExpireTime.IsZero()
+}
+
+// IsDir function checks whether the node is a directory.
+// If the node is a directory, the function will return true.
+// Otherwise the function will return false.
+func (n *node) IsDir() bool {
+	return n.Children != nil
+}
+
+// Read function gets the value of the node.
+// If the receiver node is not a key-value pair, a "Not A File" error will be returned.
+func (n *node) Read() (string, *v2error.Error) {
+	if n.IsDir() {
+		return "", v2error.NewError(v2error.EcodeNotFile, "", n.store.CurrentIndex)
+	}
+
+	return n.Value, nil
+}
+
+// Write function set the value of the node to the given value.
+// If the receiver node is a directory, a "Not A File" error will be returned.
+func (n *node) Write(value string, index uint64) *v2error.Error {
+	if n.IsDir() {
+		return v2error.NewError(v2error.EcodeNotFile, "", n.store.CurrentIndex)
+	}
+
+	n.Value = value
+	n.ModifiedIndex = index
+
+	return nil
+}
+
+func (n *node) expirationAndTTL(clock clockwork.Clock) (*time.Time, int64) {
+	if !n.IsPermanent() {
+		/* compute ttl as:
+		   ceiling( (expireTime - timeNow) / nanosecondsPerSecond )
+		   which ranges from 1..n
+		   rather than as:
+		   ( (expireTime - timeNow) / nanosecondsPerSecond ) + 1
+		   which ranges 1..n+1
+		*/
+		ttlN := n.ExpireTime.Sub(clock.Now())
+		ttl := ttlN / time.Second
+		if (ttlN % time.Second) > 0 {
+			ttl++
+		}
+		t := n.ExpireTime.UTC()
+		return &t, int64(ttl)
+	}
+	return nil, 0
+}
+
+// List function return a slice of nodes under the receiver node.
+// If the receiver node is not a directory, a "Not A Directory" error will be returned.
+func (n *node) List() ([]*node, *v2error.Error) {
+	if !n.IsDir() {
+		return nil, v2error.NewError(v2error.EcodeNotDir, "", n.store.CurrentIndex)
+	}
+
+	nodes := make([]*node, len(n.Children))
+
+	i := 0
+	for _, node := range n.Children {
+		nodes[i] = node
+		i++
+	}
+
+	return nodes, nil
+}
+
+// GetChild function returns the child node under the directory node.
+// On success, it returns the file node
+func (n *node) GetChild(name string) (*node, *v2error.Error) {
+	if !n.IsDir() {
+		return nil, v2error.NewError(v2error.EcodeNotDir, n.Path, n.store.CurrentIndex)
+	}
+
+	child, ok := n.Children[name]
+
+	if ok {
+		return child, nil
+	}
+
+	return nil, nil
+}
+
+// Add function adds a node to the receiver node.
+// If the receiver is not a directory, a "Not A Directory" error will be returned.
+// If there is an existing node with the same name under the directory, a "Already Exist"
+// error will be returned
+func (n *node) Add(child *node) *v2error.Error {
+	if !n.IsDir() {
+		return v2error.NewError(v2error.EcodeNotDir, "", n.store.CurrentIndex)
+	}
+
+	_, name := path.Split(child.Path)
+
+	if _, ok := n.Children[name]; ok {
+		return v2error.NewError(v2error.EcodeNodeExist, "", n.store.CurrentIndex)
+	}
+
+	n.Children[name] = child
+
+	return nil
+}
+
+// Remove function remove the node.
+func (n *node) Remove(dir, recursive bool, callback func(path string)) *v2error.Error {
+	if !n.IsDir() { // key-value pair
+		_, name := path.Split(n.Path)
+
+		// find its parent and remove the node from the map
+		if n.Parent != nil && n.Parent.Children[name] == n {
+			delete(n.Parent.Children, name)
+		}
+
+		if callback != nil {
+			callback(n.Path)
+		}
+
+		if !n.IsPermanent() {
+			n.store.ttlKeyHeap.remove(n)
+		}
+
+		return nil
+	}
+
+	if !dir {
+		// cannot delete a directory without dir set to true
+		return v2error.NewError(v2error.EcodeNotFile, n.Path, n.store.CurrentIndex)
+	}
+
+	if len(n.Children) != 0 && !recursive {
+		// cannot delete a directory if it is not empty and the operation
+		// is not recursive
+		return v2error.NewError(v2error.EcodeDirNotEmpty, n.Path, n.store.CurrentIndex)
+	}
+
+	for _, child := range n.Children { // delete all children
+		child.Remove(true, true, callback)
+	}
+
+	// delete self
+	_, name := path.Split(n.Path)
+	if n.Parent != nil && n.Parent.Children[name] == n {
+		delete(n.Parent.Children, name)
+
+		if callback != nil {
+			callback(n.Path)
+		}
+
+		if !n.IsPermanent() {
+			n.store.ttlKeyHeap.remove(n)
+		}
+	}
+
+	return nil
+}
+
+func (n *node) Repr(recursive, sorted bool, clock clockwork.Clock) *NodeExtern {
+	if n.IsDir() {
+		node := &NodeExtern{
+			Key:           n.Path,
+			Dir:           true,
+			ModifiedIndex: n.ModifiedIndex,
+			CreatedIndex:  n.CreatedIndex,
+		}
+		node.Expiration, node.TTL = n.expirationAndTTL(clock)
+
+		if !recursive {
+			return node
+		}
+
+		children, _ := n.List()
+		node.Nodes = make(NodeExterns, len(children))
+
+		// we do not use the index in the children slice directly
+		// we need to skip the hidden one
+		i := 0
+
+		for _, child := range children {
+			if child.IsHidden() { // get will not list hidden node
+				continue
+			}
+
+			node.Nodes[i] = child.Repr(recursive, sorted, clock)
+
+			i++
+		}
+
+		// eliminate hidden nodes
+		node.Nodes = node.Nodes[:i]
+		if sorted {
+			sort.Sort(node.Nodes)
+		}
+
+		return node
+	}
+
+	// since n.Value could be changed later, so we need to copy the value out
+	value := n.Value
+	node := &NodeExtern{
+		Key:           n.Path,
+		Value:         &value,
+		ModifiedIndex: n.ModifiedIndex,
+		CreatedIndex:  n.CreatedIndex,
+	}
+	node.Expiration, node.TTL = n.expirationAndTTL(clock)
+	return node
+}
+
+func (n *node) UpdateTTL(expireTime time.Time) {
+	if !n.IsPermanent() {
+		if expireTime.IsZero() {
+			// from ttl to permanent
+			n.ExpireTime = expireTime
+			// remove from ttl heap
+			n.store.ttlKeyHeap.remove(n)
+			return
+		}
+
+		// update ttl
+		n.ExpireTime = expireTime
+		// update ttl heap
+		n.store.ttlKeyHeap.update(n)
+		return
+	}
+
+	if expireTime.IsZero() {
+		return
+	}
+
+	// from permanent to ttl
+	n.ExpireTime = expireTime
+	// push into ttl heap
+	n.store.ttlKeyHeap.push(n)
+}
+
+// Compare function compares node index and value with provided ones.
+// second result value explains result and equals to one of Compare.. constants
+func (n *node) Compare(prevValue string, prevIndex uint64) (ok bool, which int) {
+	indexMatch := prevIndex == 0 || n.ModifiedIndex == prevIndex
+	valueMatch := prevValue == "" || n.Value == prevValue
+	ok = valueMatch && indexMatch
+	switch {
+	case valueMatch && indexMatch:
+		which = CompareMatch
+	case indexMatch && !valueMatch:
+		which = CompareValueNotMatch
+	case valueMatch && !indexMatch:
+		which = CompareIndexNotMatch
+	default:
+		which = CompareNotMatch
+	}
+	return ok, which
+}
+
+// Clone function clone the node recursively and return the new node.
+// If the node is a directory, it will clone all the content under this directory.
+// If the node is a key-value pair, it will clone the pair.
+func (n *node) Clone() *node {
+	if !n.IsDir() {
+		newkv := newKV(n.store, n.Path, n.Value, n.CreatedIndex, n.Parent, n.ExpireTime)
+		newkv.ModifiedIndex = n.ModifiedIndex
+		return newkv
+	}
+
+	clone := newDir(n.store, n.Path, n.CreatedIndex, n.Parent, n.ExpireTime)
+	clone.ModifiedIndex = n.ModifiedIndex
+
+	for key, child := range n.Children {
+		clone.Children[key] = child.Clone()
+	}
+
+	return clone
+}
+
+// recoverAndclean function help to do recovery.
+// Two things need to be done: 1. recovery structure; 2. delete expired nodes
+//
+// If the node is a directory, it will help recover children's parent pointer and recursively
+// call this function on its children.
+// We check the expire last since we need to recover the whole structure first and add all the
+// notifications into the event history.
+func (n *node) recoverAndclean() {
+	if n.IsDir() {
+		for _, child := range n.Children {
+			child.Parent = n
+			child.store = n.store
+			child.recoverAndclean()
+		}
+	}
+
+	if !n.ExpireTime.IsZero() {
+		n.store.ttlKeyHeap.push(n)
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/node_extern.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/node_extern.go
new file mode 100644
index 0000000..ff2e13e
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/node_extern.go
@@ -0,0 +1,115 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v2store
+
+import (
+	"sort"
+	"time"
+
+	"github.com/jonboulle/clockwork"
+)
+
+// NodeExtern is the external representation of the
+// internal node with additional fields
+// PrevValue is the previous value of the node
+// TTL is time to live in second
+type NodeExtern struct {
+	Key           string      `json:"key,omitempty"`
+	Value         *string     `json:"value,omitempty"`
+	Dir           bool        `json:"dir,omitempty"`
+	Expiration    *time.Time  `json:"expiration,omitempty"`
+	TTL           int64       `json:"ttl,omitempty"`
+	Nodes         NodeExterns `json:"nodes,omitempty"`
+	ModifiedIndex uint64      `json:"modifiedIndex,omitempty"`
+	CreatedIndex  uint64      `json:"createdIndex,omitempty"`
+}
+
+func (eNode *NodeExtern) loadInternalNode(n *node, recursive, sorted bool, clock clockwork.Clock) {
+	if n.IsDir() { // node is a directory
+		eNode.Dir = true
+
+		children, _ := n.List()
+		eNode.Nodes = make(NodeExterns, len(children))
+
+		// we do not use the index in the children slice directly
+		// we need to skip the hidden one
+		i := 0
+
+		for _, child := range children {
+			if child.IsHidden() { // get will not return hidden nodes
+				continue
+			}
+
+			eNode.Nodes[i] = child.Repr(recursive, sorted, clock)
+			i++
+		}
+
+		// eliminate hidden nodes
+		eNode.Nodes = eNode.Nodes[:i]
+
+		if sorted {
+			sort.Sort(eNode.Nodes)
+		}
+	} else { // node is a file
+		value, _ := n.Read()
+		eNode.Value = &value
+	}
+
+	eNode.Expiration, eNode.TTL = n.expirationAndTTL(clock)
+}
+
+func (eNode *NodeExtern) Clone() *NodeExtern {
+	if eNode == nil {
+		return nil
+	}
+	nn := &NodeExtern{
+		Key:           eNode.Key,
+		Dir:           eNode.Dir,
+		TTL:           eNode.TTL,
+		ModifiedIndex: eNode.ModifiedIndex,
+		CreatedIndex:  eNode.CreatedIndex,
+	}
+	if eNode.Value != nil {
+		s := *eNode.Value
+		nn.Value = &s
+	}
+	if eNode.Expiration != nil {
+		t := *eNode.Expiration
+		nn.Expiration = &t
+	}
+	if eNode.Nodes != nil {
+		nn.Nodes = make(NodeExterns, len(eNode.Nodes))
+		for i, n := range eNode.Nodes {
+			nn.Nodes[i] = n.Clone()
+		}
+	}
+	return nn
+}
+
+type NodeExterns []*NodeExtern
+
+// interfaces for sorting
+
+func (ns NodeExterns) Len() int {
+	return len(ns)
+}
+
+func (ns NodeExterns) Less(i, j int) bool {
+	return ns[i].Key < ns[j].Key
+}
+
+func (ns NodeExterns) Swap(i, j int) {
+	ns[i], ns[j] = ns[j], ns[i]
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/stats.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/stats.go
new file mode 100644
index 0000000..55ede56
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/stats.go
@@ -0,0 +1,145 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v2store
+
+import (
+	"encoding/json"
+	"sync/atomic"
+)
+
+const (
+	SetSuccess = iota
+	SetFail
+	DeleteSuccess
+	DeleteFail
+	CreateSuccess
+	CreateFail
+	UpdateSuccess
+	UpdateFail
+	CompareAndSwapSuccess
+	CompareAndSwapFail
+	GetSuccess
+	GetFail
+	ExpireCount
+	CompareAndDeleteSuccess
+	CompareAndDeleteFail
+)
+
+type Stats struct {
+	// Number of get requests
+
+	GetSuccess uint64 `json:"getsSuccess"`
+	GetFail    uint64 `json:"getsFail"`
+
+	// Number of sets requests
+
+	SetSuccess uint64 `json:"setsSuccess"`
+	SetFail    uint64 `json:"setsFail"`
+
+	// Number of delete requests
+
+	DeleteSuccess uint64 `json:"deleteSuccess"`
+	DeleteFail    uint64 `json:"deleteFail"`
+
+	// Number of update requests
+
+	UpdateSuccess uint64 `json:"updateSuccess"`
+	UpdateFail    uint64 `json:"updateFail"`
+
+	// Number of create requests
+
+	CreateSuccess uint64 `json:"createSuccess"`
+	CreateFail    uint64 `json:"createFail"`
+
+	// Number of testAndSet requests
+
+	CompareAndSwapSuccess uint64 `json:"compareAndSwapSuccess"`
+	CompareAndSwapFail    uint64 `json:"compareAndSwapFail"`
+
+	// Number of compareAndDelete requests
+
+	CompareAndDeleteSuccess uint64 `json:"compareAndDeleteSuccess"`
+	CompareAndDeleteFail    uint64 `json:"compareAndDeleteFail"`
+
+	ExpireCount uint64 `json:"expireCount"`
+
+	Watchers uint64 `json:"watchers"`
+}
+
+func newStats() *Stats {
+	s := new(Stats)
+	return s
+}
+
+func (s *Stats) clone() *Stats {
+	return &Stats{
+		GetSuccess:              atomic.LoadUint64(&s.GetSuccess),
+		GetFail:                 atomic.LoadUint64(&s.GetFail),
+		SetSuccess:              atomic.LoadUint64(&s.SetSuccess),
+		SetFail:                 atomic.LoadUint64(&s.SetFail),
+		DeleteSuccess:           atomic.LoadUint64(&s.DeleteSuccess),
+		DeleteFail:              atomic.LoadUint64(&s.DeleteFail),
+		UpdateSuccess:           atomic.LoadUint64(&s.UpdateSuccess),
+		UpdateFail:              atomic.LoadUint64(&s.UpdateFail),
+		CreateSuccess:           atomic.LoadUint64(&s.CreateSuccess),
+		CreateFail:              atomic.LoadUint64(&s.CreateFail),
+		CompareAndSwapSuccess:   atomic.LoadUint64(&s.CompareAndSwapSuccess),
+		CompareAndSwapFail:      atomic.LoadUint64(&s.CompareAndSwapFail),
+		CompareAndDeleteSuccess: atomic.LoadUint64(&s.CompareAndDeleteSuccess),
+		CompareAndDeleteFail:    atomic.LoadUint64(&s.CompareAndDeleteFail),
+		ExpireCount:             atomic.LoadUint64(&s.ExpireCount),
+		Watchers:                atomic.LoadUint64(&s.Watchers),
+	}
+}
+
+func (s *Stats) toJSON() []byte {
+	b, _ := json.Marshal(s)
+	return b
+}
+
+func (s *Stats) Inc(field int) {
+	switch field {
+	case SetSuccess:
+		atomic.AddUint64(&s.SetSuccess, 1)
+	case SetFail:
+		atomic.AddUint64(&s.SetFail, 1)
+	case CreateSuccess:
+		atomic.AddUint64(&s.CreateSuccess, 1)
+	case CreateFail:
+		atomic.AddUint64(&s.CreateFail, 1)
+	case DeleteSuccess:
+		atomic.AddUint64(&s.DeleteSuccess, 1)
+	case DeleteFail:
+		atomic.AddUint64(&s.DeleteFail, 1)
+	case GetSuccess:
+		atomic.AddUint64(&s.GetSuccess, 1)
+	case GetFail:
+		atomic.AddUint64(&s.GetFail, 1)
+	case UpdateSuccess:
+		atomic.AddUint64(&s.UpdateSuccess, 1)
+	case UpdateFail:
+		atomic.AddUint64(&s.UpdateFail, 1)
+	case CompareAndSwapSuccess:
+		atomic.AddUint64(&s.CompareAndSwapSuccess, 1)
+	case CompareAndSwapFail:
+		atomic.AddUint64(&s.CompareAndSwapFail, 1)
+	case CompareAndDeleteSuccess:
+		atomic.AddUint64(&s.CompareAndDeleteSuccess, 1)
+	case CompareAndDeleteFail:
+		atomic.AddUint64(&s.CompareAndDeleteFail, 1)
+	case ExpireCount:
+		atomic.AddUint64(&s.ExpireCount, 1)
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/store.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/store.go
new file mode 100644
index 0000000..2129bd6
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/store.go
@@ -0,0 +1,794 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v2store
+
+import (
+	"encoding/json"
+	"fmt"
+	"path"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/jonboulle/clockwork"
+
+	"go.etcd.io/etcd/client/pkg/v3/types"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v2error"
+)
+
+// The default version to set when the store is first initialized.
+const defaultVersion = 2
+
+var minExpireTime time.Time
+
+func init() {
+	minExpireTime, _ = time.Parse(time.RFC3339, "2000-01-01T00:00:00Z")
+}
+
+type Store interface {
+	Version() int
+	Index() uint64
+
+	Get(nodePath string, recursive, sorted bool) (*Event, error)
+	Set(nodePath string, dir bool, value string, expireOpts TTLOptionSet) (*Event, error)
+	Update(nodePath string, newValue string, expireOpts TTLOptionSet) (*Event, error)
+	Create(nodePath string, dir bool, value string, unique bool,
+		expireOpts TTLOptionSet) (*Event, error)
+	CompareAndSwap(nodePath string, prevValue string, prevIndex uint64,
+		value string, expireOpts TTLOptionSet) (*Event, error)
+	Delete(nodePath string, dir, recursive bool) (*Event, error)
+	CompareAndDelete(nodePath string, prevValue string, prevIndex uint64) (*Event, error)
+
+	Watch(prefix string, recursive, stream bool, sinceIndex uint64) (Watcher, error)
+
+	Save() ([]byte, error)
+	Recovery(state []byte) error
+
+	Clone() Store
+	SaveNoCopy() ([]byte, error)
+
+	JsonStats() []byte
+	DeleteExpiredKeys(cutoff time.Time)
+
+	HasTTLKeys() bool
+}
+
+type TTLOptionSet struct {
+	ExpireTime time.Time
+	Refresh    bool
+}
+
+type store struct {
+	Root           *node
+	WatcherHub     *watcherHub
+	CurrentIndex   uint64
+	Stats          *Stats
+	CurrentVersion int
+	ttlKeyHeap     *ttlKeyHeap  // need to recovery manually
+	worldLock      sync.RWMutex // stop the world lock
+	clock          clockwork.Clock
+	readonlySet    types.Set
+}
+
+// New creates a store where the given namespaces will be created as initial directories.
+func New(namespaces ...string) Store {
+	s := newStore(namespaces...)
+	s.clock = clockwork.NewRealClock()
+	return s
+}
+
+func newStore(namespaces ...string) *store {
+	s := new(store)
+	s.CurrentVersion = defaultVersion
+	s.Root = newDir(s, "/", s.CurrentIndex, nil, Permanent)
+	for _, namespace := range namespaces {
+		s.Root.Add(newDir(s, namespace, s.CurrentIndex, s.Root, Permanent))
+	}
+	s.Stats = newStats()
+	s.WatcherHub = newWatchHub(1000)
+	s.ttlKeyHeap = newTTLKeyHeap()
+	s.readonlySet = types.NewUnsafeSet(append(namespaces, "/")...)
+	return s
+}
+
+// Version retrieves current version of the store.
+func (s *store) Version() int {
+	return s.CurrentVersion
+}
+
+// Index retrieves the current index of the store.
+func (s *store) Index() uint64 {
+	s.worldLock.RLock()
+	defer s.worldLock.RUnlock()
+	return s.CurrentIndex
+}
+
+// Get returns a get event.
+// If recursive is true, it will return all the content under the node path.
+// If sorted is true, it will sort the content by keys.
+func (s *store) Get(nodePath string, recursive, sorted bool) (*Event, error) {
+	var err *v2error.Error
+
+	s.worldLock.RLock()
+	defer s.worldLock.RUnlock()
+
+	defer func() {
+		if err == nil {
+			s.Stats.Inc(GetSuccess)
+			if recursive {
+				reportReadSuccess(GetRecursive)
+			} else {
+				reportReadSuccess(Get)
+			}
+			return
+		}
+
+		s.Stats.Inc(GetFail)
+		if recursive {
+			reportReadFailure(GetRecursive)
+		} else {
+			reportReadFailure(Get)
+		}
+	}()
+
+	n, err := s.internalGet(nodePath)
+	if err != nil {
+		return nil, err
+	}
+
+	e := newEvent(Get, nodePath, n.ModifiedIndex, n.CreatedIndex)
+	e.EtcdIndex = s.CurrentIndex
+	e.Node.loadInternalNode(n, recursive, sorted, s.clock)
+
+	return e, nil
+}
+
+// Create creates the node at nodePath. Create will help to create intermediate directories with no ttl.
+// If the node has already existed, create will fail.
+// If any node on the path is a file, create will fail.
+func (s *store) Create(nodePath string, dir bool, value string, unique bool, expireOpts TTLOptionSet) (*Event, error) {
+	var err *v2error.Error
+
+	s.worldLock.Lock()
+	defer s.worldLock.Unlock()
+
+	defer func() {
+		if err == nil {
+			s.Stats.Inc(CreateSuccess)
+			reportWriteSuccess(Create)
+			return
+		}
+
+		s.Stats.Inc(CreateFail)
+		reportWriteFailure(Create)
+	}()
+
+	e, err := s.internalCreate(nodePath, dir, value, unique, false, expireOpts.ExpireTime, Create)
+	if err != nil {
+		return nil, err
+	}
+
+	e.EtcdIndex = s.CurrentIndex
+	s.WatcherHub.notify(e)
+
+	return e, nil
+}
+
+// Set creates or replace the node at nodePath.
+func (s *store) Set(nodePath string, dir bool, value string, expireOpts TTLOptionSet) (*Event, error) {
+	var err *v2error.Error
+
+	s.worldLock.Lock()
+	defer s.worldLock.Unlock()
+
+	defer func() {
+		if err == nil {
+			s.Stats.Inc(SetSuccess)
+			reportWriteSuccess(Set)
+			return
+		}
+
+		s.Stats.Inc(SetFail)
+		reportWriteFailure(Set)
+	}()
+
+	// Get prevNode value
+	n, getErr := s.internalGet(nodePath)
+	if getErr != nil && getErr.ErrorCode != v2error.EcodeKeyNotFound {
+		err = getErr
+		return nil, err
+	}
+
+	if expireOpts.Refresh {
+		if getErr != nil {
+			err = getErr
+			return nil, err
+		}
+		value = n.Value
+	}
+
+	// Set new value
+	e, err := s.internalCreate(nodePath, dir, value, false, true, expireOpts.ExpireTime, Set)
+	if err != nil {
+		return nil, err
+	}
+	e.EtcdIndex = s.CurrentIndex
+
+	// Put prevNode into event
+	if getErr == nil {
+		prev := newEvent(Get, nodePath, n.ModifiedIndex, n.CreatedIndex)
+		prev.Node.loadInternalNode(n, false, false, s.clock)
+		e.PrevNode = prev.Node
+	}
+
+	if !expireOpts.Refresh {
+		s.WatcherHub.notify(e)
+	} else {
+		e.SetRefresh()
+		s.WatcherHub.add(e)
+	}
+
+	return e, nil
+}
+
+// returns user-readable cause of failed comparison
+func getCompareFailCause(n *node, which int, prevValue string, prevIndex uint64) string {
+	switch which {
+	case CompareIndexNotMatch:
+		return fmt.Sprintf("[%v != %v]", prevIndex, n.ModifiedIndex)
+	case CompareValueNotMatch:
+		return fmt.Sprintf("[%v != %v]", prevValue, n.Value)
+	default:
+		return fmt.Sprintf("[%v != %v] [%v != %v]", prevValue, n.Value, prevIndex, n.ModifiedIndex)
+	}
+}
+
+func (s *store) CompareAndSwap(nodePath string, prevValue string, prevIndex uint64,
+	value string, expireOpts TTLOptionSet,
+) (*Event, error) {
+	var err *v2error.Error
+
+	s.worldLock.Lock()
+	defer s.worldLock.Unlock()
+
+	defer func() {
+		if err == nil {
+			s.Stats.Inc(CompareAndSwapSuccess)
+			reportWriteSuccess(CompareAndSwap)
+			return
+		}
+
+		s.Stats.Inc(CompareAndSwapFail)
+		reportWriteFailure(CompareAndSwap)
+	}()
+
+	nodePath = path.Clean(path.Join("/", nodePath))
+	// we do not allow the user to change "/"
+	if s.readonlySet.Contains(nodePath) {
+		return nil, v2error.NewError(v2error.EcodeRootROnly, "/", s.CurrentIndex)
+	}
+
+	n, err := s.internalGet(nodePath)
+	if err != nil {
+		return nil, err
+	}
+	if n.IsDir() { // can only compare and swap file
+		err = v2error.NewError(v2error.EcodeNotFile, nodePath, s.CurrentIndex)
+		return nil, err
+	}
+
+	// If both of the prevValue and prevIndex are given, we will test both of them.
+	// Command will be executed, only if both of the tests are successful.
+	if ok, which := n.Compare(prevValue, prevIndex); !ok {
+		cause := getCompareFailCause(n, which, prevValue, prevIndex)
+		err = v2error.NewError(v2error.EcodeTestFailed, cause, s.CurrentIndex)
+		return nil, err
+	}
+
+	if expireOpts.Refresh {
+		value = n.Value
+	}
+
+	// update etcd index
+	s.CurrentIndex++
+
+	e := newEvent(CompareAndSwap, nodePath, s.CurrentIndex, n.CreatedIndex)
+	e.EtcdIndex = s.CurrentIndex
+	e.PrevNode = n.Repr(false, false, s.clock)
+	eNode := e.Node
+
+	// if test succeed, write the value
+	if err := n.Write(value, s.CurrentIndex); err != nil {
+		return nil, err
+	}
+	n.UpdateTTL(expireOpts.ExpireTime)
+
+	// copy the value for safety
+	valueCopy := value
+	eNode.Value = &valueCopy
+	eNode.Expiration, eNode.TTL = n.expirationAndTTL(s.clock)
+
+	if !expireOpts.Refresh {
+		s.WatcherHub.notify(e)
+	} else {
+		e.SetRefresh()
+		s.WatcherHub.add(e)
+	}
+
+	return e, nil
+}
+
+// Delete deletes the node at the given path.
+// If the node is a directory, recursive must be true to delete it.
+func (s *store) Delete(nodePath string, dir, recursive bool) (*Event, error) {
+	var err *v2error.Error
+
+	s.worldLock.Lock()
+	defer s.worldLock.Unlock()
+
+	defer func() {
+		if err == nil {
+			s.Stats.Inc(DeleteSuccess)
+			reportWriteSuccess(Delete)
+			return
+		}
+
+		s.Stats.Inc(DeleteFail)
+		reportWriteFailure(Delete)
+	}()
+
+	nodePath = path.Clean(path.Join("/", nodePath))
+	// we do not allow the user to change "/"
+	if s.readonlySet.Contains(nodePath) {
+		return nil, v2error.NewError(v2error.EcodeRootROnly, "/", s.CurrentIndex)
+	}
+
+	// recursive implies dir
+	if recursive {
+		dir = true
+	}
+
+	n, err := s.internalGet(nodePath)
+	if err != nil { // if the node does not exist, return error
+		return nil, err
+	}
+
+	nextIndex := s.CurrentIndex + 1
+	e := newEvent(Delete, nodePath, nextIndex, n.CreatedIndex)
+	e.EtcdIndex = nextIndex
+	e.PrevNode = n.Repr(false, false, s.clock)
+	eNode := e.Node
+
+	if n.IsDir() {
+		eNode.Dir = true
+	}
+
+	callback := func(path string) { // notify function
+		// notify the watchers with deleted set true
+		s.WatcherHub.notifyWatchers(e, path, true)
+	}
+
+	err = n.Remove(dir, recursive, callback)
+	if err != nil {
+		return nil, err
+	}
+
+	// update etcd index
+	s.CurrentIndex++
+
+	s.WatcherHub.notify(e)
+
+	return e, nil
+}
+
+func (s *store) CompareAndDelete(nodePath string, prevValue string, prevIndex uint64) (*Event, error) {
+	var err *v2error.Error
+
+	s.worldLock.Lock()
+	defer s.worldLock.Unlock()
+
+	defer func() {
+		if err == nil {
+			s.Stats.Inc(CompareAndDeleteSuccess)
+			reportWriteSuccess(CompareAndDelete)
+			return
+		}
+
+		s.Stats.Inc(CompareAndDeleteFail)
+		reportWriteFailure(CompareAndDelete)
+	}()
+
+	nodePath = path.Clean(path.Join("/", nodePath))
+
+	n, err := s.internalGet(nodePath)
+	if err != nil { // if the node does not exist, return error
+		return nil, err
+	}
+	if n.IsDir() { // can only compare and delete file
+		return nil, v2error.NewError(v2error.EcodeNotFile, nodePath, s.CurrentIndex)
+	}
+
+	// If both of the prevValue and prevIndex are given, we will test both of them.
+	// Command will be executed, only if both of the tests are successful.
+	if ok, which := n.Compare(prevValue, prevIndex); !ok {
+		cause := getCompareFailCause(n, which, prevValue, prevIndex)
+		return nil, v2error.NewError(v2error.EcodeTestFailed, cause, s.CurrentIndex)
+	}
+
+	// update etcd index
+	s.CurrentIndex++
+
+	e := newEvent(CompareAndDelete, nodePath, s.CurrentIndex, n.CreatedIndex)
+	e.EtcdIndex = s.CurrentIndex
+	e.PrevNode = n.Repr(false, false, s.clock)
+
+	callback := func(path string) { // notify function
+		// notify the watchers with deleted set true
+		s.WatcherHub.notifyWatchers(e, path, true)
+	}
+
+	err = n.Remove(false, false, callback)
+	if err != nil {
+		return nil, err
+	}
+
+	s.WatcherHub.notify(e)
+
+	return e, nil
+}
+
+func (s *store) Watch(key string, recursive, stream bool, sinceIndex uint64) (Watcher, error) {
+	s.worldLock.RLock()
+	defer s.worldLock.RUnlock()
+
+	key = path.Clean(path.Join("/", key))
+	if sinceIndex == 0 {
+		sinceIndex = s.CurrentIndex + 1
+	}
+	// WatcherHub does not know about the current index, so we need to pass it in
+	w, err := s.WatcherHub.watch(key, recursive, stream, sinceIndex, s.CurrentIndex)
+	if err != nil {
+		return nil, err
+	}
+
+	return w, nil
+}
+
+// walk walks all the nodePath and apply the walkFunc on each directory
+func (s *store) walk(nodePath string, walkFunc func(prev *node, component string) (*node, *v2error.Error)) (*node, *v2error.Error) {
+	components := strings.Split(nodePath, "/")
+
+	curr := s.Root
+	var err *v2error.Error
+
+	for i := 1; i < len(components); i++ {
+		if len(components[i]) == 0 { // ignore empty string
+			return curr, nil
+		}
+
+		curr, err = walkFunc(curr, components[i])
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return curr, nil
+}
+
+// Update updates the value/ttl of the node.
+// If the node is a file, the value and the ttl can be updated.
+// If the node is a directory, only the ttl can be updated.
+func (s *store) Update(nodePath string, newValue string, expireOpts TTLOptionSet) (*Event, error) {
+	var err *v2error.Error
+
+	s.worldLock.Lock()
+	defer s.worldLock.Unlock()
+
+	defer func() {
+		if err == nil {
+			s.Stats.Inc(UpdateSuccess)
+			reportWriteSuccess(Update)
+			return
+		}
+
+		s.Stats.Inc(UpdateFail)
+		reportWriteFailure(Update)
+	}()
+
+	nodePath = path.Clean(path.Join("/", nodePath))
+	// we do not allow the user to change "/"
+	if s.readonlySet.Contains(nodePath) {
+		return nil, v2error.NewError(v2error.EcodeRootROnly, "/", s.CurrentIndex)
+	}
+
+	currIndex, nextIndex := s.CurrentIndex, s.CurrentIndex+1
+
+	n, err := s.internalGet(nodePath)
+	if err != nil { // if the node does not exist, return error
+		return nil, err
+	}
+	if n.IsDir() && len(newValue) != 0 {
+		// if the node is a directory, we cannot update value to non-empty
+		return nil, v2error.NewError(v2error.EcodeNotFile, nodePath, currIndex)
+	}
+
+	if expireOpts.Refresh {
+		newValue = n.Value
+	}
+
+	e := newEvent(Update, nodePath, nextIndex, n.CreatedIndex)
+	e.EtcdIndex = nextIndex
+	e.PrevNode = n.Repr(false, false, s.clock)
+	eNode := e.Node
+
+	if err := n.Write(newValue, nextIndex); err != nil {
+		return nil, fmt.Errorf("nodePath %v : %w", nodePath, err)
+	}
+
+	if n.IsDir() {
+		eNode.Dir = true
+	} else {
+		// copy the value for safety
+		newValueCopy := newValue
+		eNode.Value = &newValueCopy
+	}
+
+	// update ttl
+	n.UpdateTTL(expireOpts.ExpireTime)
+
+	eNode.Expiration, eNode.TTL = n.expirationAndTTL(s.clock)
+
+	if !expireOpts.Refresh {
+		s.WatcherHub.notify(e)
+	} else {
+		e.SetRefresh()
+		s.WatcherHub.add(e)
+	}
+
+	s.CurrentIndex = nextIndex
+
+	return e, nil
+}
+
+func (s *store) internalCreate(nodePath string, dir bool, value string, unique, replace bool,
+	expireTime time.Time, action string,
+) (*Event, *v2error.Error) {
+	currIndex, nextIndex := s.CurrentIndex, s.CurrentIndex+1
+
+	if unique { // append unique item under the node path
+		nodePath += "/" + fmt.Sprintf("%020s", strconv.FormatUint(nextIndex, 10))
+	}
+
+	nodePath = path.Clean(path.Join("/", nodePath))
+
+	// we do not allow the user to change "/"
+	if s.readonlySet.Contains(nodePath) {
+		return nil, v2error.NewError(v2error.EcodeRootROnly, "/", currIndex)
+	}
+
+	// Assume expire times that are way in the past are
+	// This can occur when the time is serialized to JS
+	if expireTime.Before(minExpireTime) {
+		expireTime = Permanent
+	}
+
+	dirName, nodeName := path.Split(nodePath)
+
+	// walk through the nodePath, create dirs and get the last directory node
+	d, err := s.walk(dirName, s.checkDir)
+	if err != nil {
+		s.Stats.Inc(SetFail)
+		reportWriteFailure(action)
+		err.Index = currIndex
+		return nil, err
+	}
+
+	e := newEvent(action, nodePath, nextIndex, nextIndex)
+	eNode := e.Node
+
+	n, _ := d.GetChild(nodeName)
+
+	// force will try to replace an existing file
+	if n != nil {
+		if !replace {
+			return nil, v2error.NewError(v2error.EcodeNodeExist, nodePath, currIndex)
+		}
+		if n.IsDir() {
+			return nil, v2error.NewError(v2error.EcodeNotFile, nodePath, currIndex)
+		}
+		e.PrevNode = n.Repr(false, false, s.clock)
+
+		if err := n.Remove(false, false, nil); err != nil {
+			return nil, err
+		}
+	}
+
+	if !dir { // create file
+		// copy the value for safety
+		valueCopy := value
+		eNode.Value = &valueCopy
+
+		n = newKV(s, nodePath, value, nextIndex, d, expireTime)
+	} else { // create directory
+		eNode.Dir = true
+
+		n = newDir(s, nodePath, nextIndex, d, expireTime)
+	}
+
+	// we are sure d is a directory and does not have the children with name n.Name
+	if err := d.Add(n); err != nil {
+		return nil, err
+	}
+
+	// node with TTL
+	if !n.IsPermanent() {
+		s.ttlKeyHeap.push(n)
+
+		eNode.Expiration, eNode.TTL = n.expirationAndTTL(s.clock)
+	}
+
+	s.CurrentIndex = nextIndex
+
+	return e, nil
+}
+
+// InternalGet gets the node of the given nodePath.
+func (s *store) internalGet(nodePath string) (*node, *v2error.Error) {
+	nodePath = path.Clean(path.Join("/", nodePath))
+
+	walkFunc := func(parent *node, name string) (*node, *v2error.Error) {
+		if !parent.IsDir() {
+			err := v2error.NewError(v2error.EcodeNotDir, parent.Path, s.CurrentIndex)
+			return nil, err
+		}
+
+		child, ok := parent.Children[name]
+		if ok {
+			return child, nil
+		}
+
+		return nil, v2error.NewError(v2error.EcodeKeyNotFound, path.Join(parent.Path, name), s.CurrentIndex)
+	}
+
+	f, err := s.walk(nodePath, walkFunc)
+	if err != nil {
+		return nil, err
+	}
+	return f, nil
+}
+
+// DeleteExpiredKeys will delete all expired keys
+func (s *store) DeleteExpiredKeys(cutoff time.Time) {
+	s.worldLock.Lock()
+	defer s.worldLock.Unlock()
+
+	for {
+		node := s.ttlKeyHeap.top()
+		if node == nil || node.ExpireTime.After(cutoff) {
+			break
+		}
+
+		s.CurrentIndex++
+		e := newEvent(Expire, node.Path, s.CurrentIndex, node.CreatedIndex)
+		e.EtcdIndex = s.CurrentIndex
+		e.PrevNode = node.Repr(false, false, s.clock)
+		if node.IsDir() {
+			e.Node.Dir = true
+		}
+
+		callback := func(path string) { // notify function
+			// notify the watchers with deleted set true
+			s.WatcherHub.notifyWatchers(e, path, true)
+		}
+
+		s.ttlKeyHeap.pop()
+		node.Remove(true, true, callback)
+
+		reportExpiredKey()
+		s.Stats.Inc(ExpireCount)
+
+		s.WatcherHub.notify(e)
+	}
+}
+
+// checkDir will check whether the component is a directory under parent node.
+// If it is a directory, this function will return the pointer to that node.
+// If it does not exist, this function will create a new directory and return the pointer to that node.
+// If it is a file, this function will return error.
+func (s *store) checkDir(parent *node, dirName string) (*node, *v2error.Error) {
+	node, ok := parent.Children[dirName]
+
+	if ok {
+		if node.IsDir() {
+			return node, nil
+		}
+
+		return nil, v2error.NewError(v2error.EcodeNotDir, node.Path, s.CurrentIndex)
+	}
+
+	n := newDir(s, path.Join(parent.Path, dirName), s.CurrentIndex+1, parent, Permanent)
+
+	parent.Children[dirName] = n
+
+	return n, nil
+}
+
+// Save saves the static state of the store system.
+// It will not be able to save the state of watchers.
+// It will not save the parent field of the node. Or there will
+// be cyclic dependencies issue for the json package.
+func (s *store) Save() ([]byte, error) {
+	b, err := json.Marshal(s.Clone())
+	if err != nil {
+		return nil, err
+	}
+
+	return b, nil
+}
+
+func (s *store) SaveNoCopy() ([]byte, error) {
+	b, err := json.Marshal(s)
+	if err != nil {
+		return nil, err
+	}
+
+	return b, nil
+}
+
+func (s *store) Clone() Store {
+	s.worldLock.RLock()
+
+	clonedStore := newStore()
+	clonedStore.CurrentIndex = s.CurrentIndex
+	clonedStore.Root = s.Root.Clone()
+	clonedStore.WatcherHub = s.WatcherHub.clone()
+	clonedStore.Stats = s.Stats.clone()
+	clonedStore.CurrentVersion = s.CurrentVersion
+
+	s.worldLock.RUnlock()
+	return clonedStore
+}
+
+// Recovery recovers the store system from a static state
+// It needs to recover the parent field of the nodes.
+// It needs to delete the expired nodes since the saved time and also
+// needs to create monitoring goroutines.
+func (s *store) Recovery(state []byte) error {
+	s.worldLock.Lock()
+	defer s.worldLock.Unlock()
+	err := json.Unmarshal(state, s)
+	if err != nil {
+		return err
+	}
+
+	s.ttlKeyHeap = newTTLKeyHeap()
+
+	s.Root.recoverAndclean()
+	return nil
+}
+
+//revive:disable:var-naming
+func (s *store) JsonStats() []byte {
+	//revive:enable:var-naming
+	s.Stats.Watchers = uint64(s.WatcherHub.count)
+	return s.Stats.toJSON()
+}
+
+func (s *store) HasTTLKeys() bool {
+	s.worldLock.RLock()
+	defer s.worldLock.RUnlock()
+	return s.ttlKeyHeap.Len() != 0
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/ttl_key_heap.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/ttl_key_heap.go
new file mode 100644
index 0000000..77ca8e9
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/ttl_key_heap.go
@@ -0,0 +1,97 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v2store
+
+import "container/heap"
+
+// An TTLKeyHeap is a min-heap of TTLKeys order by expiration time
+type ttlKeyHeap struct {
+	array  []*node
+	keyMap map[*node]int
+}
+
+func newTTLKeyHeap() *ttlKeyHeap {
+	h := &ttlKeyHeap{keyMap: make(map[*node]int)}
+	heap.Init(h)
+	return h
+}
+
+func (h ttlKeyHeap) Len() int {
+	return len(h.array)
+}
+
+func (h ttlKeyHeap) Less(i, j int) bool {
+	return h.array[i].ExpireTime.Before(h.array[j].ExpireTime)
+}
+
+func (h ttlKeyHeap) Swap(i, j int) {
+	// swap node
+	h.array[i], h.array[j] = h.array[j], h.array[i]
+
+	// update map
+	h.keyMap[h.array[i]] = i
+	h.keyMap[h.array[j]] = j
+}
+
+func (h *ttlKeyHeap) Push(x any) {
+	n, _ := x.(*node)
+	h.keyMap[n] = len(h.array)
+	h.array = append(h.array, n)
+}
+
+func (h *ttlKeyHeap) Pop() any {
+	old := h.array
+	n := len(old)
+	x := old[n-1]
+	// Set slice element to nil, so GC can recycle the node.
+	// This is due to golang GC doesn't support partial recycling:
+	// https://github.com/golang/go/issues/9618
+	old[n-1] = nil
+	h.array = old[0 : n-1]
+	delete(h.keyMap, x)
+	return x
+}
+
+func (h *ttlKeyHeap) top() *node {
+	if h.Len() != 0 {
+		return h.array[0]
+	}
+	return nil
+}
+
+func (h *ttlKeyHeap) pop() *node {
+	x := heap.Pop(h)
+	n, _ := x.(*node)
+	return n
+}
+
+func (h *ttlKeyHeap) push(x any) {
+	heap.Push(h, x)
+}
+
+func (h *ttlKeyHeap) update(n *node) {
+	index, ok := h.keyMap[n]
+	if ok {
+		heap.Remove(h, index)
+		heap.Push(h, n)
+	}
+}
+
+func (h *ttlKeyHeap) remove(n *node) {
+	index, ok := h.keyMap[n]
+	if ok {
+		heap.Remove(h, index)
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/watcher.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/watcher.go
new file mode 100644
index 0000000..4b1e846
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/watcher.go
@@ -0,0 +1,95 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v2store
+
+type Watcher interface {
+	EventChan() chan *Event
+	StartIndex() uint64 // The EtcdIndex at which the Watcher was created
+	Remove()
+}
+
+type watcher struct {
+	eventChan  chan *Event
+	stream     bool
+	recursive  bool
+	sinceIndex uint64
+	startIndex uint64
+	hub        *watcherHub
+	removed    bool
+	remove     func()
+}
+
+func (w *watcher) EventChan() chan *Event {
+	return w.eventChan
+}
+
+func (w *watcher) StartIndex() uint64 {
+	return w.startIndex
+}
+
+// notify function notifies the watcher. If the watcher interests in the given path,
+// the function will return true.
+func (w *watcher) notify(e *Event, originalPath bool, deleted bool) bool {
+	// watcher is interested the path in three cases and under one condition
+	// the condition is that the event happens after the watcher's sinceIndex
+
+	// 1. the path at which the event happens is the path the watcher is watching at.
+	// For example if the watcher is watching at "/foo" and the event happens at "/foo",
+	// the watcher must be interested in that event.
+
+	// 2. the watcher is a recursive watcher, it interests in the event happens after
+	// its watching path. For example if watcher A watches at "/foo" and it is a recursive
+	// one, it will interest in the event happens at "/foo/bar".
+
+	// 3. when we delete a directory, we need to force notify all the watchers who watches
+	// at the file we need to delete.
+	// For example a watcher is watching at "/foo/bar". And we deletes "/foo". The watcher
+	// should get notified even if "/foo" is not the path it is watching.
+	if (w.recursive || originalPath || deleted) && e.Index() >= w.sinceIndex {
+		// We cannot block here if the eventChan capacity is full, otherwise
+		// etcd will hang. eventChan capacity is full when the rate of
+		// notifications are higher than our send rate.
+		// If this happens, we close the channel.
+		select {
+		case w.eventChan <- e:
+		default:
+			// We have missed a notification. Remove the watcher.
+			// Removing the watcher also closes the eventChan.
+			w.remove()
+		}
+		return true
+	}
+	return false
+}
+
+// Remove removes the watcher from watcherHub
+// The actual remove function is guaranteed to only be executed once
+func (w *watcher) Remove() {
+	w.hub.mutex.Lock()
+	defer w.hub.mutex.Unlock()
+
+	close(w.eventChan)
+	if w.remove != nil {
+		w.remove()
+	}
+}
+
+// nopWatcher is a watcher that receives nothing, always blocking.
+type nopWatcher struct{}
+
+func NewNopWatcher() Watcher                 { return &nopWatcher{} }
+func (w *nopWatcher) EventChan() chan *Event { return nil }
+func (w *nopWatcher) StartIndex() uint64     { return 0 }
+func (w *nopWatcher) Remove()                {}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/watcher_hub.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/watcher_hub.go
new file mode 100644
index 0000000..df5ae78
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v2store/watcher_hub.go
@@ -0,0 +1,199 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v2store
+
+import (
+	"container/list"
+	"path"
+	"strings"
+	"sync"
+	"sync/atomic"
+
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v2error"
+)
+
+// A watcherHub contains all subscribed watchers
+// watchers is a map with watched path as key and watcher as value
+// EventHistory keeps the old events for watcherHub. It is used to help
+// watcher to get a continuous event history. Or a watcher might miss the
+// event happens between the end of the first watch command and the start
+// of the second command.
+type watcherHub struct {
+	// count must be the first element to keep 64-bit alignment for atomic
+	// access
+
+	count int64 // current number of watchers.
+
+	mutex        sync.Mutex
+	watchers     map[string]*list.List
+	EventHistory *EventHistory
+}
+
+// newWatchHub creates a watcherHub. The capacity determines how many events we will
+// keep in the eventHistory.
+// Typically, we only need to keep a small size of history[smaller than 20K].
+// Ideally, it should smaller than 20K/s[max throughput] * 2 * 50ms[RTT] = 2000
+func newWatchHub(capacity int) *watcherHub {
+	return &watcherHub{
+		watchers:     make(map[string]*list.List),
+		EventHistory: newEventHistory(capacity),
+	}
+}
+
+// Watch function returns a Watcher.
+// If recursive is true, the first change after index under key will be sent to the event channel of the watcher.
+// If recursive is false, the first change after index at key will be sent to the event channel of the watcher.
+// If index is zero, watch will start from the current index + 1.
+func (wh *watcherHub) watch(key string, recursive, stream bool, index, storeIndex uint64) (Watcher, *v2error.Error) {
+	reportWatchRequest()
+	event, err := wh.EventHistory.scan(key, recursive, index)
+	if err != nil {
+		err.Index = storeIndex
+		return nil, err
+	}
+
+	w := &watcher{
+		eventChan:  make(chan *Event, 100), // use a buffered channel
+		recursive:  recursive,
+		stream:     stream,
+		sinceIndex: index,
+		startIndex: storeIndex,
+		hub:        wh,
+	}
+
+	wh.mutex.Lock()
+	defer wh.mutex.Unlock()
+	// If the event exists in the known history, append the EtcdIndex and return immediately
+	if event != nil {
+		ne := event.Clone()
+		ne.EtcdIndex = storeIndex
+		w.eventChan <- ne
+		return w, nil
+	}
+
+	l, ok := wh.watchers[key]
+
+	var elem *list.Element
+
+	if ok { // add the new watcher to the back of the list
+		elem = l.PushBack(w)
+	} else { // create a new list and add the new watcher
+		l = list.New()
+		elem = l.PushBack(w)
+		wh.watchers[key] = l
+	}
+
+	w.remove = func() {
+		if w.removed { // avoid removing it twice
+			return
+		}
+		w.removed = true
+		l.Remove(elem)
+		atomic.AddInt64(&wh.count, -1)
+		reportWatcherRemoved()
+		if l.Len() == 0 {
+			delete(wh.watchers, key)
+		}
+	}
+
+	atomic.AddInt64(&wh.count, 1)
+	reportWatcherAdded()
+
+	return w, nil
+}
+
+func (wh *watcherHub) add(e *Event) {
+	wh.EventHistory.addEvent(e)
+}
+
+// notify function accepts an event and notify to the watchers.
+func (wh *watcherHub) notify(e *Event) {
+	e = wh.EventHistory.addEvent(e) // add event into the eventHistory
+
+	segments := strings.Split(e.Node.Key, "/")
+
+	currPath := "/"
+
+	// walk through all the segments of the path and notify the watchers
+	// if the path is "/foo/bar", it will notify watchers with path "/",
+	// "/foo" and "/foo/bar"
+
+	for _, segment := range segments {
+		currPath = path.Join(currPath, segment)
+		// notify the watchers who interests in the changes of current path
+		wh.notifyWatchers(e, currPath, false)
+	}
+}
+
+func (wh *watcherHub) notifyWatchers(e *Event, nodePath string, deleted bool) {
+	wh.mutex.Lock()
+	defer wh.mutex.Unlock()
+
+	l, ok := wh.watchers[nodePath]
+	if ok {
+		curr := l.Front()
+
+		for curr != nil {
+			next := curr.Next() // save reference to the next one in the list
+
+			w, _ := curr.Value.(*watcher)
+
+			originalPath := e.Node.Key == nodePath
+			if (originalPath || !isHidden(nodePath, e.Node.Key)) && w.notify(e, originalPath, deleted) {
+				if !w.stream { // do not remove the stream watcher
+					// if we successfully notify a watcher
+					// we need to remove the watcher from the list
+					// and decrease the counter
+					w.removed = true
+					l.Remove(curr)
+					atomic.AddInt64(&wh.count, -1)
+					reportWatcherRemoved()
+				}
+			}
+
+			curr = next // update current to the next element in the list
+		}
+
+		if l.Len() == 0 {
+			// if we have notified all watcher in the list
+			// we can delete the list
+			delete(wh.watchers, nodePath)
+		}
+	}
+}
+
+// clone function clones the watcherHub and return the cloned one.
+// only clone the static content. do not clone the current watchers.
+func (wh *watcherHub) clone() *watcherHub {
+	clonedHistory := wh.EventHistory.clone()
+
+	return &watcherHub{
+		EventHistory: clonedHistory,
+	}
+}
+
+// isHidden checks to see if key path is considered hidden to watch path i.e. the
+// last element is hidden or it's within a hidden directory
+func isHidden(watchPath, keyPath string) bool {
+	// When deleting a directory, watchPath might be deeper than the actual keyPath
+	// For example, when deleting /foo we also need to notify watchers on /foo/bar.
+	if len(watchPath) > len(keyPath) {
+		return false
+	}
+	// if watch path is just a "/", after path will start without "/"
+	// add a "/" to deal with the special case when watchPath is "/"
+	afterPath := path.Clean("/" + keyPath[len(watchPath):])
+	return strings.Contains(afterPath, "/_")
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3alarm/alarms.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3alarm/alarms.go
new file mode 100644
index 0000000..bf17929
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3alarm/alarms.go
@@ -0,0 +1,128 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package v3alarm manages health status alarms in etcd.
+package v3alarm
+
+import (
+	"sync"
+
+	"go.uber.org/zap"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/client/pkg/v3/types"
+	"go.etcd.io/etcd/server/v3/storage/backend"
+	"go.etcd.io/etcd/server/v3/storage/schema"
+)
+
+type BackendGetter interface {
+	Backend() backend.Backend
+}
+
+type alarmSet map[types.ID]*pb.AlarmMember
+
+// AlarmStore persists alarms to the backend.
+type AlarmStore struct {
+	lg    *zap.Logger
+	mu    sync.Mutex
+	types map[pb.AlarmType]alarmSet
+
+	be schema.AlarmBackend
+}
+
+func NewAlarmStore(lg *zap.Logger, be schema.AlarmBackend) (*AlarmStore, error) {
+	if lg == nil {
+		lg = zap.NewNop()
+	}
+	ret := &AlarmStore{lg: lg, types: make(map[pb.AlarmType]alarmSet), be: be}
+	err := ret.restore()
+	return ret, err
+}
+
+func (a *AlarmStore) Activate(id types.ID, at pb.AlarmType) *pb.AlarmMember {
+	a.mu.Lock()
+	defer a.mu.Unlock()
+
+	newAlarm := &pb.AlarmMember{MemberID: uint64(id), Alarm: at}
+	if m := a.addToMap(newAlarm); m != newAlarm {
+		return m
+	}
+
+	a.be.MustPutAlarm(newAlarm)
+	return newAlarm
+}
+
+func (a *AlarmStore) Deactivate(id types.ID, at pb.AlarmType) *pb.AlarmMember {
+	a.mu.Lock()
+	defer a.mu.Unlock()
+
+	t := a.types[at]
+	if t == nil {
+		t = make(alarmSet)
+		a.types[at] = t
+	}
+	m := t[id]
+	if m == nil {
+		return nil
+	}
+
+	delete(t, id)
+
+	a.be.MustDeleteAlarm(m)
+	return m
+}
+
+func (a *AlarmStore) Get(at pb.AlarmType) (ret []*pb.AlarmMember) {
+	a.mu.Lock()
+	defer a.mu.Unlock()
+	if at == pb.AlarmType_NONE {
+		for _, t := range a.types {
+			for _, m := range t {
+				ret = append(ret, m)
+			}
+		}
+		return ret
+	}
+	for _, m := range a.types[at] {
+		ret = append(ret, m)
+	}
+	return ret
+}
+
+func (a *AlarmStore) restore() error {
+	a.be.CreateAlarmBucket()
+	ms, err := a.be.GetAllAlarms()
+	if err != nil {
+		return err
+	}
+	for _, m := range ms {
+		a.addToMap(m)
+	}
+	a.be.ForceCommit()
+	return err
+}
+
+func (a *AlarmStore) addToMap(newAlarm *pb.AlarmMember) *pb.AlarmMember {
+	t := a.types[newAlarm.Alarm]
+	if t == nil {
+		t = make(alarmSet)
+		a.types[newAlarm.Alarm] = t
+	}
+	m := t[types.ID(newAlarm.MemberID)]
+	if m != nil {
+		return m
+	}
+	t[types.ID(newAlarm.MemberID)] = newAlarm
+	return newAlarm
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3client/doc.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3client/doc.go
new file mode 100644
index 0000000..a6a4d7e
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3client/doc.go
@@ -0,0 +1,44 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package v3client provides clientv3 interfaces from an etcdserver.
+//
+// Use v3client by creating an EtcdServer instance, then wrapping it with v3client.New:
+//
+//	import (
+//		"context"
+//
+//		"go.etcd.io/etcd/server/v3/embed"
+//		"go.etcd.io/etcd/server/v3/etcdserver/api/v3client"
+//	)
+//
+//	...
+//
+//	// create an embedded EtcdServer from the default configuration
+//	cfg := embed.NewConfig()
+//	cfg.Dir = "default.etcd"
+//	e, err := embed.StartEtcd(cfg)
+//	if err != nil {
+//		// handle error!
+//	}
+//
+//	// wrap the EtcdServer with v3client
+//	cli := v3client.New(e.Server)
+//
+//	// use like an ordinary clientv3
+//	resp, err := cli.Put(context.TODO(), "some-key", "it works!")
+//	if err != nil {
+//		// handle error!
+//	}
+package v3client
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3client/v3client.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3client/v3client.go
new file mode 100644
index 0000000..b9d1839
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3client/v3client.go
@@ -0,0 +1,67 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v3client
+
+import (
+	"context"
+	"time"
+
+	clientv3 "go.etcd.io/etcd/client/v3"
+	"go.etcd.io/etcd/server/v3/etcdserver"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc"
+	"go.etcd.io/etcd/server/v3/proxy/grpcproxy/adapter"
+)
+
+// New creates a clientv3 client that wraps an in-process EtcdServer. Instead
+// of making gRPC calls through sockets, the client makes direct function calls
+// to the etcd server through its api/v3rpc function interfaces.
+func New(s *etcdserver.EtcdServer) *clientv3.Client {
+	c := clientv3.NewCtxClient(context.Background(), clientv3.WithZapLogger(s.Logger()))
+
+	kvc := adapter.KvServerToKvClient(v3rpc.NewQuotaKVServer(s))
+	c.KV = clientv3.NewKVFromKVClient(kvc, c)
+
+	lc := adapter.LeaseServerToLeaseClient(v3rpc.NewQuotaLeaseServer(s))
+	c.Lease = clientv3.NewLeaseFromLeaseClient(lc, c, time.Second)
+
+	wc := adapter.WatchServerToWatchClient(v3rpc.NewWatchServer(s))
+	c.Watcher = &watchWrapper{clientv3.NewWatchFromWatchClient(wc, c)}
+
+	mc := adapter.MaintenanceServerToMaintenanceClient(v3rpc.NewMaintenanceServer(s, nil))
+	c.Maintenance = clientv3.NewMaintenanceFromMaintenanceClient(mc, c)
+
+	clc := adapter.ClusterServerToClusterClient(v3rpc.NewClusterServer(s))
+	c.Cluster = clientv3.NewClusterFromClusterClient(clc, c)
+
+	a := adapter.AuthServerToAuthClient(v3rpc.NewAuthServer(s))
+	c.Auth = clientv3.NewAuthFromAuthClient(a, c)
+
+	return c
+}
+
+// BlankContext implements Stringer on a context so the ctx string doesn't
+// depend on the context's WithValue data, which tends to be unsynchronized
+// (e.g., x/net/trace), causing ctx.String() to throw data races.
+type blankContext struct{ context.Context }
+
+func (*blankContext) String() string { return "(blankCtx)" }
+
+// watchWrapper wraps clientv3 watch calls to blank out the context
+// to avoid races on trace data.
+type watchWrapper struct{ clientv3.Watcher }
+
+func (ww *watchWrapper) Watch(ctx context.Context, key string, opts ...clientv3.OpOption) clientv3.WatchChan {
+	return ww.Watcher.Watch(&blankContext{ctx}, key, opts...)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3compactor/compactor.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3compactor/compactor.go
new file mode 100644
index 0000000..f916e71
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3compactor/compactor.go
@@ -0,0 +1,73 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v3compactor
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/jonboulle/clockwork"
+	"go.uber.org/zap"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+)
+
+const (
+	ModePeriodic = "periodic"
+	ModeRevision = "revision"
+)
+
+// Compactor purges old log from the storage periodically.
+type Compactor interface {
+	// Run starts the main loop of the compactor in background.
+	// Use Stop() to halt the loop and release the resource.
+	Run()
+	// Stop halts the main loop of the compactor.
+	Stop()
+	// Pause temporally suspend the compactor not to run compaction. Resume() to unpose.
+	Pause()
+	// Resume restarts the compactor suspended by Pause().
+	Resume()
+}
+
+type Compactable interface {
+	Compact(ctx context.Context, r *pb.CompactionRequest) (*pb.CompactionResponse, error)
+}
+
+type RevGetter interface {
+	Rev() int64
+}
+
+// New returns a new Compactor based on given "mode".
+func New(
+	lg *zap.Logger,
+	mode string,
+	retention time.Duration,
+	rg RevGetter,
+	c Compactable,
+) (Compactor, error) {
+	if lg == nil {
+		lg = zap.NewNop()
+	}
+	switch mode {
+	case ModePeriodic:
+		return newPeriodic(lg, clockwork.NewRealClock(), retention, rg, c), nil
+	case ModeRevision:
+		return newRevision(lg, clockwork.NewRealClock(), int64(retention), rg, c), nil
+	default:
+		return nil, fmt.Errorf("unsupported compaction mode %s", mode)
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3compactor/doc.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3compactor/doc.go
new file mode 100644
index 0000000..bb28046
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3compactor/doc.go
@@ -0,0 +1,16 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package v3compactor implements automated policies for compacting etcd's mvcc storage.
+package v3compactor
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3compactor/periodic.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3compactor/periodic.go
new file mode 100644
index 0000000..7468d23
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3compactor/periodic.go
@@ -0,0 +1,208 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v3compactor
+
+import (
+	"context"
+	"errors"
+	"sync"
+	"time"
+
+	"github.com/jonboulle/clockwork"
+	"go.uber.org/zap"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/server/v3/storage/mvcc"
+)
+
+// Periodic compacts the log by purging revisions older than
+// the configured retention time.
+type Periodic struct {
+	lg     *zap.Logger
+	clock  clockwork.Clock
+	period time.Duration
+
+	rg RevGetter
+	c  Compactable
+
+	revs   []int64
+	ctx    context.Context
+	cancel context.CancelFunc
+
+	// mu protects paused
+	mu     sync.RWMutex
+	paused bool
+}
+
+// newPeriodic creates a new instance of Periodic compactor that purges
+// the log older than h Duration.
+func newPeriodic(lg *zap.Logger, clock clockwork.Clock, h time.Duration, rg RevGetter, c Compactable) *Periodic {
+	pc := &Periodic{
+		lg:     lg,
+		clock:  clock,
+		period: h,
+		rg:     rg,
+		c:      c,
+	}
+	// revs won't be longer than the retentions.
+	pc.revs = make([]int64, 0, pc.getRetentions())
+	pc.ctx, pc.cancel = context.WithCancel(context.Background())
+	return pc
+}
+
+/*
+Compaction period 1-hour:
+  1. compute compaction period, which is 1-hour
+  2. record revisions for every 1/10 of 1-hour (6-minute)
+  3. keep recording revisions with no compaction for first 1-hour
+  4. do compact with revs[0]
+	- success? continue on for-loop and move sliding window; revs = revs[1:]
+	- failure? update revs, and retry after 1/10 of 1-hour (6-minute)
+
+Compaction period 24-hour:
+  1. compute compaction period, which is 24-hour
+  2. record revisions for every 1/10 of 24-hour (144-minute)
+  3. keep recording revisions with no compaction for first 24-hour
+  4. do compact with revs[0]
+	- success? continue on for-loop and move sliding window; revs = revs[1:]
+	- failure? update revs, and retry after 1/10 of 24-hour (144-minute)
+
+Compaction period 59-min:
+  1. compute compaction period, which is 59-min
+  2. record revisions for every 1/10 of 59-min (5.9-min)
+  3. keep recording revisions with no compaction for first 59-min
+  4. do compact with revs[0]
+	- success? continue on for-loop and move sliding window; revs = revs[1:]
+	- failure? update revs, and retry after 1/10 of 59-min (5.9-min)
+
+Compaction period 5-sec:
+  1. compute compaction period, which is 5-sec
+  2. record revisions for every 1/10 of 5-sec (0.5-sec)
+  3. keep recording revisions with no compaction for first 5-sec
+  4. do compact with revs[0]
+	- success? continue on for-loop and move sliding window; revs = revs[1:]
+	- failure? update revs, and retry after 1/10 of 5-sec (0.5-sec)
+*/
+
+// Run runs periodic compactor.
+func (pc *Periodic) Run() {
+	compactInterval := pc.getCompactInterval()
+	retryInterval := pc.getRetryInterval()
+	retentions := pc.getRetentions()
+
+	go func() {
+		lastRevision := int64(0)
+		lastSuccess := pc.clock.Now()
+		baseInterval := pc.period
+		for {
+			pc.revs = append(pc.revs, pc.rg.Rev())
+			if len(pc.revs) > retentions {
+				pc.revs = pc.revs[1:] // pc.revs[0] is always the rev at pc.period ago
+			}
+
+			select {
+			case <-pc.ctx.Done():
+				return
+			case <-pc.clock.After(retryInterval):
+				pc.mu.RLock()
+				p := pc.paused
+				pc.mu.RUnlock()
+				if p {
+					continue
+				}
+			}
+			rev := pc.revs[0]
+			if pc.clock.Now().Sub(lastSuccess) < baseInterval || rev == lastRevision {
+				continue
+			}
+
+			// wait up to initial given period
+			if baseInterval == pc.period {
+				baseInterval = compactInterval
+			}
+
+			pc.lg.Info(
+				"starting auto periodic compaction",
+				zap.Int64("revision", rev),
+				zap.Duration("compact-period", pc.period),
+			)
+			startTime := pc.clock.Now()
+			_, err := pc.c.Compact(pc.ctx, &pb.CompactionRequest{Revision: rev})
+			if err == nil || errors.Is(err, mvcc.ErrCompacted) {
+				pc.lg.Info(
+					"completed auto periodic compaction",
+					zap.Int64("revision", rev),
+					zap.Duration("compact-period", pc.period),
+					zap.Duration("took", pc.clock.Now().Sub(startTime)),
+				)
+				lastRevision = rev
+				lastSuccess = pc.clock.Now()
+			} else {
+				pc.lg.Warn(
+					"failed auto periodic compaction",
+					zap.Int64("revision", rev),
+					zap.Duration("compact-period", pc.period),
+					zap.Duration("retry-interval", retryInterval),
+					zap.Error(err),
+				)
+			}
+		}
+	}()
+}
+
+// if given compaction period x is <1-hour, compact every x duration.
+// (e.g. --auto-compaction-mode 'periodic' --auto-compaction-retention='10m', then compact every 10-minute)
+// if given compaction period x is >1-hour, compact every hour.
+// (e.g. --auto-compaction-mode 'periodic' --auto-compaction-retention='2h', then compact every 1-hour)
+func (pc *Periodic) getCompactInterval() time.Duration {
+	itv := pc.period
+	if itv > time.Hour {
+		itv = time.Hour
+	}
+	return itv
+}
+
+func (pc *Periodic) getRetentions() int {
+	return int(pc.period/pc.getRetryInterval()) + 1
+}
+
+const retryDivisor = 10
+
+func (pc *Periodic) getRetryInterval() time.Duration {
+	itv := pc.period
+	if itv > time.Hour {
+		itv = time.Hour
+	}
+	return itv / retryDivisor
+}
+
+// Stop stops periodic compactor.
+func (pc *Periodic) Stop() {
+	pc.cancel()
+}
+
+// Pause pauses periodic compactor.
+func (pc *Periodic) Pause() {
+	pc.mu.Lock()
+	pc.paused = true
+	pc.mu.Unlock()
+}
+
+// Resume resumes periodic compactor.
+func (pc *Periodic) Resume() {
+	pc.mu.Lock()
+	pc.paused = false
+	pc.mu.Unlock()
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3compactor/revision.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3compactor/revision.go
new file mode 100644
index 0000000..4174861
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3compactor/revision.go
@@ -0,0 +1,131 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v3compactor
+
+import (
+	"context"
+	"errors"
+	"sync"
+	"time"
+
+	"github.com/jonboulle/clockwork"
+	"go.uber.org/zap"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/server/v3/storage/mvcc"
+)
+
+// Revision compacts the log by purging revisions older than
+// the configured reivison number. Compaction happens every 5 minutes.
+type Revision struct {
+	lg *zap.Logger
+
+	clock     clockwork.Clock
+	retention int64
+
+	rg RevGetter
+	c  Compactable
+
+	ctx    context.Context
+	cancel context.CancelFunc
+
+	mu     sync.Mutex
+	paused bool
+}
+
+// newRevision creates a new instance of Revisonal compactor that purges
+// the log older than retention revisions from the current revision.
+func newRevision(lg *zap.Logger, clock clockwork.Clock, retention int64, rg RevGetter, c Compactable) *Revision {
+	rc := &Revision{
+		lg:        lg,
+		clock:     clock,
+		retention: retention,
+		rg:        rg,
+		c:         c,
+	}
+	rc.ctx, rc.cancel = context.WithCancel(context.Background())
+	return rc
+}
+
+const revInterval = 5 * time.Minute
+
+// Run runs revision-based compactor.
+func (rc *Revision) Run() {
+	prev := int64(0)
+	go func() {
+		for {
+			select {
+			case <-rc.ctx.Done():
+				return
+			case <-rc.clock.After(revInterval):
+				rc.mu.Lock()
+				p := rc.paused
+				rc.mu.Unlock()
+				if p {
+					continue
+				}
+			}
+
+			rev := rc.rg.Rev() - rc.retention
+			if rev <= 0 || rev == prev {
+				continue
+			}
+
+			now := time.Now()
+			rc.lg.Info(
+				"starting auto revision compaction",
+				zap.Int64("revision", rev),
+				zap.Int64("revision-compaction-retention", rc.retention),
+			)
+			_, err := rc.c.Compact(rc.ctx, &pb.CompactionRequest{Revision: rev})
+			if err == nil || errors.Is(err, mvcc.ErrCompacted) {
+				prev = rev
+				rc.lg.Info(
+					"completed auto revision compaction",
+					zap.Int64("revision", rev),
+					zap.Int64("revision-compaction-retention", rc.retention),
+					zap.Duration("took", time.Since(now)),
+				)
+			} else {
+				rc.lg.Warn(
+					"failed auto revision compaction",
+					zap.Int64("revision", rev),
+					zap.Int64("revision-compaction-retention", rc.retention),
+					zap.Duration("retry-interval", revInterval),
+					zap.Error(err),
+				)
+			}
+		}
+	}()
+}
+
+// Stop stops revision-based compactor.
+func (rc *Revision) Stop() {
+	rc.cancel()
+}
+
+// Pause pauses revision-based compactor.
+func (rc *Revision) Pause() {
+	rc.mu.Lock()
+	rc.paused = true
+	rc.mu.Unlock()
+}
+
+// Resume resumes revision-based compactor.
+func (rc *Revision) Resume() {
+	rc.mu.Lock()
+	rc.paused = false
+	rc.mu.Unlock()
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3discovery/discovery.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3discovery/discovery.go
new file mode 100644
index 0000000..7fe231c
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3discovery/discovery.go
@@ -0,0 +1,509 @@
+// Copyright 2022 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package v3discovery provides an implementation of the cluster discovery that
+// is used by etcd with v3 client.
+package v3discovery
+
+import (
+	"context"
+	"errors"
+	"math"
+	"path"
+	"sort"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/jonboulle/clockwork"
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/client/pkg/v3/types"
+	clientv3 "go.etcd.io/etcd/client/v3"
+)
+
+const (
+	discoveryPrefix = "/_etcd/registry"
+)
+
+var (
+	ErrInvalidURL     = errors.New("discovery: invalid peer URL")
+	ErrBadSizeKey     = errors.New("discovery: size key is bad")
+	ErrSizeNotFound   = errors.New("discovery: size key not found")
+	ErrFullCluster    = errors.New("discovery: cluster is full")
+	ErrTooManyRetries = errors.New("discovery: too many retries")
+)
+
+var (
+	// Number of retries discovery will attempt before giving up and error out.
+	nRetries              = uint(math.MaxUint32)
+	maxExponentialRetries = uint(8)
+)
+
+type DiscoveryConfig struct {
+	clientv3.ConfigSpec `json:"client"`
+	Token               string `json:"token"`
+}
+
+type memberInfo struct {
+	// peerRegKey is the key used by the member when registering in the
+	// discovery service.
+	// Format: "/_etcd/registry/<ClusterToken>/members/<memberID>".
+	peerRegKey string
+	// peerURLsMap format: "peerName=peerURLs", i.e., "member1=http://127.0.0.1:2380".
+	peerURLsMap string
+	// createRev is the member's CreateRevision in the etcd cluster backing
+	// the discovery service.
+	createRev int64
+}
+
+type clusterInfo struct {
+	clusterToken string
+	members      []memberInfo
+}
+
+// key prefix for each cluster: "/_etcd/registry/<ClusterToken>".
+func getClusterKeyPrefix(cluster string) string {
+	return path.Join(discoveryPrefix, cluster)
+}
+
+// key format for cluster size: "/_etcd/registry/<ClusterToken>/_config/size".
+func getClusterSizeKey(cluster string) string {
+	return path.Join(getClusterKeyPrefix(cluster), "_config/size")
+}
+
+// key prefix for each member: "/_etcd/registry/<ClusterToken>/members".
+func getMemberKeyPrefix(clusterToken string) string {
+	return path.Join(getClusterKeyPrefix(clusterToken), "members")
+}
+
+// key format for each member: "/_etcd/registry/<ClusterToken>/members/<memberID>".
+func getMemberKey(cluster, memberID string) string {
+	return path.Join(getMemberKeyPrefix(cluster), memberID)
+}
+
+// GetCluster will connect to the discovery service at the given endpoints and
+// retrieve a string describing the cluster
+func GetCluster(lg *zap.Logger, cfg *DiscoveryConfig) (cs string, rerr error) {
+	d, err := newDiscovery(lg, cfg, 0)
+	if err != nil {
+		return "", err
+	}
+
+	defer d.close()
+	defer func() {
+		if rerr != nil {
+			d.lg.Error(
+				"discovery failed to get cluster",
+				zap.String("cluster", cs),
+				zap.Error(rerr),
+			)
+		} else {
+			d.lg.Info(
+				"discovery got cluster successfully",
+				zap.String("cluster", cs),
+			)
+		}
+	}()
+
+	return d.getCluster()
+}
+
+// JoinCluster will connect to the discovery service at the endpoints, and
+// register the server represented by the given id and config to the cluster.
+// The parameter `config` is supposed to be in the format "memberName=peerURLs",
+// such as "member1=http://127.0.0.1:2380".
+//
+// The final returned string has the same format as "--initial-cluster", such as
+// "infra1=http://127.0.0.1:12380,infra2=http://127.0.0.1:22380,infra3=http://127.0.0.1:32380".
+func JoinCluster(lg *zap.Logger, cfg *DiscoveryConfig, id types.ID, config string) (cs string, rerr error) {
+	d, err := newDiscovery(lg, cfg, id)
+	if err != nil {
+		return "", err
+	}
+
+	defer d.close()
+	defer func() {
+		if rerr != nil {
+			d.lg.Error(
+				"discovery failed to join cluster",
+				zap.String("cluster", cs),
+				zap.Error(rerr),
+			)
+		} else {
+			d.lg.Info(
+				"discovery joined cluster successfully",
+				zap.String("cluster", cs),
+			)
+		}
+	}()
+
+	return d.joinCluster(config)
+}
+
+type discovery struct {
+	lg           *zap.Logger
+	clusterToken string
+	memberID     types.ID
+	c            *clientv3.Client
+	retries      uint
+
+	cfg *DiscoveryConfig
+
+	clock clockwork.Clock
+}
+
+func newDiscovery(lg *zap.Logger, dcfg *DiscoveryConfig, id types.ID) (*discovery, error) {
+	if lg == nil {
+		lg = zap.NewNop()
+	}
+
+	lg = lg.With(zap.String("discovery-token", dcfg.Token), zap.String("discovery-endpoints", strings.Join(dcfg.Endpoints, ",")))
+	cfg, err := clientv3.NewClientConfig(&dcfg.ConfigSpec, lg)
+	if err != nil {
+		return nil, err
+	}
+
+	c, err := clientv3.New(*cfg)
+	if err != nil {
+		return nil, err
+	}
+	return &discovery{
+		lg:           lg,
+		clusterToken: dcfg.Token,
+		memberID:     id,
+		c:            c,
+		cfg:          dcfg,
+		clock:        clockwork.NewRealClock(),
+	}, nil
+}
+
+func (d *discovery) getCluster() (string, error) {
+	cls, clusterSize, rev, err := d.checkCluster()
+	if err != nil {
+		if errors.Is(err, ErrFullCluster) {
+			return cls.getInitClusterStr(clusterSize)
+		}
+		return "", err
+	}
+
+	for cls.Len() < clusterSize {
+		d.waitPeers(cls, clusterSize, rev)
+	}
+
+	return cls.getInitClusterStr(clusterSize)
+}
+
+func (d *discovery) joinCluster(config string) (string, error) {
+	_, _, _, err := d.checkCluster()
+	if err != nil {
+		return "", err
+	}
+
+	if err = d.registerSelf(config); err != nil {
+		return "", err
+	}
+
+	cls, clusterSize, rev, err := d.checkCluster()
+	if err != nil {
+		return "", err
+	}
+
+	for cls.Len() < clusterSize {
+		d.waitPeers(cls, clusterSize, rev)
+	}
+
+	return cls.getInitClusterStr(clusterSize)
+}
+
+func (d *discovery) getClusterSize() (int, error) {
+	configKey := getClusterSizeKey(d.clusterToken)
+	ctx, cancel := context.WithTimeout(context.Background(), d.cfg.RequestTimeout)
+	defer cancel()
+
+	resp, err := d.c.Get(ctx, configKey)
+	if err != nil {
+		d.lg.Warn(
+			"failed to get cluster size from discovery service",
+			zap.String("clusterSizeKey", configKey),
+			zap.Error(err),
+		)
+		return 0, err
+	}
+
+	if len(resp.Kvs) == 0 {
+		return 0, ErrSizeNotFound
+	}
+
+	clusterSize, err := strconv.ParseInt(string(resp.Kvs[0].Value), 10, 0)
+	if err != nil || clusterSize <= 0 {
+		return 0, ErrBadSizeKey
+	}
+
+	return int(clusterSize), nil
+}
+
+func (d *discovery) getClusterMembers() (*clusterInfo, int64, error) {
+	membersKeyPrefix := getMemberKeyPrefix(d.clusterToken)
+	ctx, cancel := context.WithTimeout(context.Background(), d.cfg.RequestTimeout)
+	defer cancel()
+
+	resp, err := d.c.Get(ctx, membersKeyPrefix, clientv3.WithPrefix())
+	if err != nil {
+		d.lg.Warn(
+			"failed to get cluster members from discovery service",
+			zap.String("membersKeyPrefix", membersKeyPrefix),
+			zap.Error(err),
+		)
+		return nil, 0, err
+	}
+
+	cls := &clusterInfo{clusterToken: d.clusterToken}
+	for _, kv := range resp.Kvs {
+		mKey := strings.TrimSpace(string(kv.Key))
+		mValue := strings.TrimSpace(string(kv.Value))
+
+		if err := cls.add(mKey, mValue, kv.CreateRevision); err != nil {
+			d.lg.Warn(
+				err.Error(),
+				zap.String("memberKey", mKey),
+				zap.String("memberInfo", mValue),
+			)
+		} else {
+			d.lg.Info(
+				"found peer from discovery service",
+				zap.String("memberKey", mKey),
+				zap.String("memberInfo", mValue),
+			)
+		}
+	}
+
+	return cls, resp.Header.Revision, nil
+}
+
+func (d *discovery) checkClusterRetry() (*clusterInfo, int, int64, error) {
+	if d.retries < nRetries {
+		d.logAndBackoffForRetry("cluster status check")
+		return d.checkCluster()
+	}
+	return nil, 0, 0, ErrTooManyRetries
+}
+
+func (d *discovery) checkCluster() (*clusterInfo, int, int64, error) {
+	clusterSize, err := d.getClusterSize()
+	if err != nil {
+		if errors.Is(err, ErrSizeNotFound) || errors.Is(err, ErrBadSizeKey) {
+			return nil, 0, 0, err
+		}
+
+		return d.checkClusterRetry()
+	}
+
+	cls, rev, err := d.getClusterMembers()
+	if err != nil {
+		return d.checkClusterRetry()
+	}
+	d.retries = 0
+
+	// find self position
+	memberSelfID := getMemberKey(d.clusterToken, d.memberID.String())
+	idx := 0
+	for _, m := range cls.members {
+		if m.peerRegKey == memberSelfID {
+			break
+		}
+		if idx >= clusterSize-1 {
+			return cls, clusterSize, rev, ErrFullCluster
+		}
+		idx++
+	}
+	return cls, clusterSize, rev, nil
+}
+
+func (d *discovery) registerSelfRetry(contents string) error {
+	if d.retries < nRetries {
+		d.logAndBackoffForRetry("register member itself")
+		return d.registerSelf(contents)
+	}
+	return ErrTooManyRetries
+}
+
+func (d *discovery) registerSelf(contents string) error {
+	ctx, cancel := context.WithTimeout(context.Background(), d.cfg.RequestTimeout)
+	memberKey := getMemberKey(d.clusterToken, d.memberID.String())
+	_, err := d.c.Put(ctx, memberKey, contents)
+	cancel()
+
+	if err != nil {
+		d.lg.Warn(
+			"failed to register members itself to the discovery service",
+			zap.String("memberKey", memberKey),
+			zap.Error(err),
+		)
+		return d.registerSelfRetry(contents)
+	}
+	d.retries = 0
+
+	d.lg.Info(
+		"register member itself successfully",
+		zap.String("memberKey", memberKey),
+		zap.String("memberInfo", contents),
+	)
+
+	return nil
+}
+
+func (d *discovery) waitPeers(cls *clusterInfo, clusterSize int, rev int64) {
+	// watch from the next revision
+	membersKeyPrefix := getMemberKeyPrefix(d.clusterToken)
+	w := d.c.Watch(context.Background(), membersKeyPrefix, clientv3.WithPrefix(), clientv3.WithRev(rev+1))
+
+	d.lg.Info(
+		"waiting for peers from discovery service",
+		zap.Int("clusterSize", clusterSize),
+		zap.Int("found-peers", cls.Len()),
+	)
+
+	// waiting for peers until all needed peers are returned
+	for wresp := range w {
+		for _, ev := range wresp.Events {
+			mKey := strings.TrimSpace(string(ev.Kv.Key))
+			mValue := strings.TrimSpace(string(ev.Kv.Value))
+
+			if err := cls.add(mKey, mValue, ev.Kv.CreateRevision); err != nil {
+				d.lg.Warn(
+					err.Error(),
+					zap.String("memberKey", mKey),
+					zap.String("memberInfo", mValue),
+				)
+			} else {
+				d.lg.Info(
+					"found peer from discovery service",
+					zap.String("memberKey", mKey),
+					zap.String("memberInfo", mValue),
+				)
+			}
+		}
+
+		if cls.Len() >= clusterSize {
+			break
+		}
+	}
+
+	d.lg.Info(
+		"found all needed peers from discovery service",
+		zap.Int("clusterSize", clusterSize),
+		zap.Int("found-peers", cls.Len()),
+	)
+}
+
+func (d *discovery) logAndBackoffForRetry(step string) {
+	d.retries++
+	// logAndBackoffForRetry stops exponential backoff when the retries are
+	// more than maxExpoentialRetries and is set to a constant backoff afterward.
+	retries := d.retries
+	if retries > maxExponentialRetries {
+		retries = maxExponentialRetries
+	}
+	retryTimeInSecond := time.Duration(0x1<<retries) * time.Second
+	d.lg.Warn(
+		"retry connecting to discovery service",
+		zap.String("reason", step),
+		zap.Duration("backoff", retryTimeInSecond),
+	)
+	d.clock.Sleep(retryTimeInSecond)
+}
+
+func (d *discovery) close() error {
+	if d.c != nil {
+		return d.c.Close()
+	}
+	return nil
+}
+
+func (cls *clusterInfo) Len() int { return len(cls.members) }
+func (cls *clusterInfo) Less(i, j int) bool {
+	return cls.members[i].createRev < cls.members[j].createRev
+}
+
+func (cls *clusterInfo) Swap(i, j int) {
+	cls.members[i], cls.members[j] = cls.members[j], cls.members[i]
+}
+
+func (cls *clusterInfo) add(memberKey, memberValue string, rev int64) error {
+	membersKeyPrefix := getMemberKeyPrefix(cls.clusterToken)
+
+	if !strings.HasPrefix(memberKey, membersKeyPrefix) {
+		// It should never happen because previously we used exactly the
+		// same ${membersKeyPrefix} to get or watch the member list.
+		return errors.New("invalid peer registry key")
+	}
+
+	if !strings.ContainsRune(memberValue, '=') {
+		// It must be in the format "member1=http://127.0.0.1:2380".
+		return errors.New("invalid peer info returned from discovery service")
+	}
+
+	if cls.exist(memberKey) {
+		return errors.New("found duplicate peer from discovery service")
+	}
+
+	cls.members = append(cls.members, memberInfo{
+		peerRegKey:  memberKey,
+		peerURLsMap: memberValue,
+		createRev:   rev,
+	})
+
+	// When multiple members register at the same time, then number of
+	// registered members may be larger than the configured cluster size.
+	// So we sort all the members on the CreateRevision in ascending order,
+	// and get the first ${clusterSize} members in this case.
+	sort.Sort(cls)
+
+	return nil
+}
+
+func (cls *clusterInfo) exist(mKey string) bool {
+	// Usually there are just a couple of members, so performance shouldn't be a problem.
+	for _, m := range cls.members {
+		if mKey == m.peerRegKey {
+			return true
+		}
+	}
+	return false
+}
+
+func (cls *clusterInfo) getInitClusterStr(clusterSize int) (string, error) {
+	peerURLs := cls.getPeerURLs()
+
+	if len(peerURLs) > clusterSize {
+		peerURLs = peerURLs[:clusterSize]
+	}
+
+	us := strings.Join(peerURLs, ",")
+	_, err := types.NewURLsMap(us)
+	if err != nil {
+		return us, ErrInvalidURL
+	}
+
+	return us, nil
+}
+
+func (cls *clusterInfo) getPeerURLs() []string {
+	var peerURLs []string
+	for _, peer := range cls.members {
+		peerURLs = append(peerURLs, peer.peerURLsMap)
+	}
+	return peerURLs
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3election/doc.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3election/doc.go
new file mode 100644
index 0000000..d6fefd7
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3election/doc.go
@@ -0,0 +1,16 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package v3election provides a v3 election service from an etcdserver.
+package v3election
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3election/election.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3election/election.go
new file mode 100644
index 0000000..77a9c4b
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3election/election.go
@@ -0,0 +1,134 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v3election
+
+import (
+	"context"
+	"errors"
+
+	clientv3 "go.etcd.io/etcd/client/v3"
+	"go.etcd.io/etcd/client/v3/concurrency"
+	epb "go.etcd.io/etcd/server/v3/etcdserver/api/v3election/v3electionpb"
+)
+
+// ErrMissingLeaderKey is returned when election API request
+// is missing the "leader" field.
+var ErrMissingLeaderKey = errors.New(`"leader" field must be provided`)
+
+type electionServer struct {
+	c *clientv3.Client
+}
+
+func NewElectionServer(c *clientv3.Client) epb.ElectionServer {
+	return &electionServer{c}
+}
+
+func (es *electionServer) Campaign(ctx context.Context, req *epb.CampaignRequest) (*epb.CampaignResponse, error) {
+	s, err := es.session(ctx, req.Lease)
+	if err != nil {
+		return nil, err
+	}
+	e := concurrency.NewElection(s, string(req.Name))
+	if err = e.Campaign(ctx, string(req.Value)); err != nil {
+		return nil, err
+	}
+	return &epb.CampaignResponse{
+		Header: e.Header(),
+		Leader: &epb.LeaderKey{
+			Name:  req.Name,
+			Key:   []byte(e.Key()),
+			Rev:   e.Rev(),
+			Lease: int64(s.Lease()),
+		},
+	}, nil
+}
+
+func (es *electionServer) Proclaim(ctx context.Context, req *epb.ProclaimRequest) (*epb.ProclaimResponse, error) {
+	if req.Leader == nil {
+		return nil, ErrMissingLeaderKey
+	}
+	s, err := es.session(ctx, req.Leader.Lease)
+	if err != nil {
+		return nil, err
+	}
+	e := concurrency.ResumeElection(s, string(req.Leader.Name), string(req.Leader.Key), req.Leader.Rev)
+	if err := e.Proclaim(ctx, string(req.Value)); err != nil {
+		return nil, err
+	}
+	return &epb.ProclaimResponse{Header: e.Header()}, nil
+}
+
+func (es *electionServer) Observe(req *epb.LeaderRequest, stream epb.Election_ObserveServer) error {
+	s, err := es.session(stream.Context(), -1)
+	if err != nil {
+		return err
+	}
+	e := concurrency.NewElection(s, string(req.Name))
+	ch := e.Observe(stream.Context())
+	for stream.Context().Err() == nil {
+		select {
+		case <-stream.Context().Done():
+		case resp, ok := <-ch:
+			if !ok {
+				return nil
+			}
+			lresp := &epb.LeaderResponse{Header: resp.Header, Kv: resp.Kvs[0]}
+			if err := stream.Send(lresp); err != nil {
+				return err
+			}
+		}
+	}
+	return stream.Context().Err()
+}
+
+func (es *electionServer) Leader(ctx context.Context, req *epb.LeaderRequest) (*epb.LeaderResponse, error) {
+	s, err := es.session(ctx, -1)
+	if err != nil {
+		return nil, err
+	}
+	l, lerr := concurrency.NewElection(s, string(req.Name)).Leader(ctx)
+	if lerr != nil {
+		return nil, lerr
+	}
+	return &epb.LeaderResponse{Header: l.Header, Kv: l.Kvs[0]}, nil
+}
+
+func (es *electionServer) Resign(ctx context.Context, req *epb.ResignRequest) (*epb.ResignResponse, error) {
+	if req.Leader == nil {
+		return nil, ErrMissingLeaderKey
+	}
+	s, err := es.session(ctx, req.Leader.Lease)
+	if err != nil {
+		return nil, err
+	}
+	e := concurrency.ResumeElection(s, string(req.Leader.Name), string(req.Leader.Key), req.Leader.Rev)
+	if err := e.Resign(ctx); err != nil {
+		return nil, err
+	}
+	return &epb.ResignResponse{Header: e.Header()}, nil
+}
+
+func (es *electionServer) session(ctx context.Context, lease int64) (*concurrency.Session, error) {
+	s, err := concurrency.NewSession(
+		es.c,
+		concurrency.WithLease(clientv3.LeaseID(lease)),
+		concurrency.WithContext(ctx),
+	)
+	if err != nil {
+		return nil, err
+	}
+	s.Orphan()
+	return s, nil
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3election/v3electionpb/gw/v3election.pb.gw.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3election/v3electionpb/gw/v3election.pb.gw.go
new file mode 100644
index 0000000..912149f
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3election/v3electionpb/gw/v3election.pb.gw.go
@@ -0,0 +1,395 @@
+// Code generated by protoc-gen-grpc-gateway. DO NOT EDIT.
+// source: server/etcdserver/api/v3election/v3electionpb/v3election.proto
+
+/*
+Package v3electionpb is a reverse proxy.
+
+It translates gRPC into RESTful JSON APIs.
+*/
+package gw
+
+import (
+	protov1 "github.com/golang/protobuf/proto"
+
+	"context"
+	"errors"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v3election/v3electionpb"
+	"io"
+	"net/http"
+
+	"github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
+	"github.com/grpc-ecosystem/grpc-gateway/v2/utilities"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/grpclog"
+	"google.golang.org/grpc/metadata"
+	"google.golang.org/grpc/status"
+	"google.golang.org/protobuf/proto"
+)
+
+// Suppress "imported and not used" errors
+var (
+	_ codes.Code
+	_ io.Reader
+	_ status.Status
+	_ = errors.New
+	_ = runtime.String
+	_ = utilities.NewDoubleArray
+	_ = metadata.Join
+)
+
+func request_Election_Campaign_0(ctx context.Context, marshaler runtime.Marshaler, client v3electionpb.ElectionClient, req *http.Request, pathParams map[string]string) (proto.Message, runtime.ServerMetadata, error) {
+	var (
+		protoReq v3electionpb.CampaignRequest
+		metadata runtime.ServerMetadata
+	)
+	if err := marshaler.NewDecoder(req.Body).Decode(protov1.MessageV2(&protoReq)); err != nil && !errors.Is(err, io.EOF) {
+		return nil, metadata, status.Errorf(codes.InvalidArgument, "%v", err)
+	}
+	msg, err := client.Campaign(ctx, &protoReq, grpc.Header(&metadata.HeaderMD), grpc.Trailer(&metadata.TrailerMD))
+	return protov1.MessageV2(msg), metadata, err
+}
+
+func local_request_Election_Campaign_0(ctx context.Context, marshaler runtime.Marshaler, server v3electionpb.ElectionServer, req *http.Request, pathParams map[string]string) (proto.Message, runtime.ServerMetadata, error) {
+	var (
+		protoReq v3electionpb.CampaignRequest
+		metadata runtime.ServerMetadata
+	)
+	if err := marshaler.NewDecoder(req.Body).Decode(protov1.MessageV2(&protoReq)); err != nil && !errors.Is(err, io.EOF) {
+		return nil, metadata, status.Errorf(codes.InvalidArgument, "%v", err)
+	}
+	msg, err := server.Campaign(ctx, &protoReq)
+	return protov1.MessageV2(msg), metadata, err
+}
+
+func request_Election_Proclaim_0(ctx context.Context, marshaler runtime.Marshaler, client v3electionpb.ElectionClient, req *http.Request, pathParams map[string]string) (proto.Message, runtime.ServerMetadata, error) {
+	var (
+		protoReq v3electionpb.ProclaimRequest
+		metadata runtime.ServerMetadata
+	)
+	if err := marshaler.NewDecoder(req.Body).Decode(protov1.MessageV2(&protoReq)); err != nil && !errors.Is(err, io.EOF) {
+		return nil, metadata, status.Errorf(codes.InvalidArgument, "%v", err)
+	}
+	msg, err := client.Proclaim(ctx, &protoReq, grpc.Header(&metadata.HeaderMD), grpc.Trailer(&metadata.TrailerMD))
+	return protov1.MessageV2(msg), metadata, err
+}
+
+func local_request_Election_Proclaim_0(ctx context.Context, marshaler runtime.Marshaler, server v3electionpb.ElectionServer, req *http.Request, pathParams map[string]string) (proto.Message, runtime.ServerMetadata, error) {
+	var (
+		protoReq v3electionpb.ProclaimRequest
+		metadata runtime.ServerMetadata
+	)
+	if err := marshaler.NewDecoder(req.Body).Decode(protov1.MessageV2(&protoReq)); err != nil && !errors.Is(err, io.EOF) {
+		return nil, metadata, status.Errorf(codes.InvalidArgument, "%v", err)
+	}
+	msg, err := server.Proclaim(ctx, &protoReq)
+	return protov1.MessageV2(msg), metadata, err
+}
+
+func request_Election_Leader_0(ctx context.Context, marshaler runtime.Marshaler, client v3electionpb.ElectionClient, req *http.Request, pathParams map[string]string) (proto.Message, runtime.ServerMetadata, error) {
+	var (
+		protoReq v3electionpb.LeaderRequest
+		metadata runtime.ServerMetadata
+	)
+	if err := marshaler.NewDecoder(req.Body).Decode(protov1.MessageV2(&protoReq)); err != nil && !errors.Is(err, io.EOF) {
+		return nil, metadata, status.Errorf(codes.InvalidArgument, "%v", err)
+	}
+	msg, err := client.Leader(ctx, &protoReq, grpc.Header(&metadata.HeaderMD), grpc.Trailer(&metadata.TrailerMD))
+	return protov1.MessageV2(msg), metadata, err
+}
+
+func local_request_Election_Leader_0(ctx context.Context, marshaler runtime.Marshaler, server v3electionpb.ElectionServer, req *http.Request, pathParams map[string]string) (proto.Message, runtime.ServerMetadata, error) {
+	var (
+		protoReq v3electionpb.LeaderRequest
+		metadata runtime.ServerMetadata
+	)
+	if err := marshaler.NewDecoder(req.Body).Decode(protov1.MessageV2(&protoReq)); err != nil && !errors.Is(err, io.EOF) {
+		return nil, metadata, status.Errorf(codes.InvalidArgument, "%v", err)
+	}
+	msg, err := server.Leader(ctx, &protoReq)
+	return protov1.MessageV2(msg), metadata, err
+}
+
+func request_Election_Observe_0(ctx context.Context, marshaler runtime.Marshaler, client v3electionpb.ElectionClient, req *http.Request, pathParams map[string]string) (v3electionpb.Election_ObserveClient, runtime.ServerMetadata, error) {
+	var (
+		protoReq v3electionpb.LeaderRequest
+		metadata runtime.ServerMetadata
+	)
+	if err := marshaler.NewDecoder(req.Body).Decode(protov1.MessageV2(&protoReq)); err != nil && !errors.Is(err, io.EOF) {
+		return nil, metadata, status.Errorf(codes.InvalidArgument, "%v", err)
+	}
+	stream, err := client.Observe(ctx, &protoReq)
+	if err != nil {
+		return nil, metadata, err
+	}
+	header, err := stream.Header()
+	if err != nil {
+		return nil, metadata, err
+	}
+	metadata.HeaderMD = header
+	return stream, metadata, nil
+}
+
+func request_Election_Resign_0(ctx context.Context, marshaler runtime.Marshaler, client v3electionpb.ElectionClient, req *http.Request, pathParams map[string]string) (proto.Message, runtime.ServerMetadata, error) {
+	var (
+		protoReq v3electionpb.ResignRequest
+		metadata runtime.ServerMetadata
+	)
+	if err := marshaler.NewDecoder(req.Body).Decode(protov1.MessageV2(&protoReq)); err != nil && !errors.Is(err, io.EOF) {
+		return nil, metadata, status.Errorf(codes.InvalidArgument, "%v", err)
+	}
+	msg, err := client.Resign(ctx, &protoReq, grpc.Header(&metadata.HeaderMD), grpc.Trailer(&metadata.TrailerMD))
+	return protov1.MessageV2(msg), metadata, err
+}
+
+func local_request_Election_Resign_0(ctx context.Context, marshaler runtime.Marshaler, server v3electionpb.ElectionServer, req *http.Request, pathParams map[string]string) (proto.Message, runtime.ServerMetadata, error) {
+	var (
+		protoReq v3electionpb.ResignRequest
+		metadata runtime.ServerMetadata
+	)
+	if err := marshaler.NewDecoder(req.Body).Decode(protov1.MessageV2(&protoReq)); err != nil && !errors.Is(err, io.EOF) {
+		return nil, metadata, status.Errorf(codes.InvalidArgument, "%v", err)
+	}
+	msg, err := server.Resign(ctx, &protoReq)
+	return protov1.MessageV2(msg), metadata, err
+}
+
+// v3electionpb.RegisterElectionHandlerServer registers the http handlers for service Election to "mux".
+// UnaryRPC     :call v3electionpb.ElectionServer directly.
+// StreamingRPC :currently unsupported pending https://github.com/grpc/grpc-go/issues/906.
+// Note that using this registration option will cause many gRPC library features to stop working. Consider using RegisterElectionHandlerFromEndpoint instead.
+// GRPC interceptors will not work for this type of registration. To use interceptors, you must use the "runtime.WithMiddlewares" option in the "runtime.NewServeMux" call.
+func RegisterElectionHandlerServer(ctx context.Context, mux *runtime.ServeMux, server v3electionpb.ElectionServer) error {
+	mux.Handle(http.MethodPost, pattern_Election_Campaign_0, func(w http.ResponseWriter, req *http.Request, pathParams map[string]string) {
+		ctx, cancel := context.WithCancel(req.Context())
+		defer cancel()
+		var stream runtime.ServerTransportStream
+		ctx = grpc.NewContextWithServerTransportStream(ctx, &stream)
+		inboundMarshaler, outboundMarshaler := runtime.MarshalerForRequest(mux, req)
+		annotatedContext, err := runtime.AnnotateIncomingContext(ctx, mux, req, "/v3electionpb.Election/Campaign", runtime.WithHTTPPathPattern("/v3/election/campaign"))
+		if err != nil {
+			runtime.HTTPError(ctx, mux, outboundMarshaler, w, req, err)
+			return
+		}
+		resp, md, err := local_request_Election_Campaign_0(annotatedContext, inboundMarshaler, server, req, pathParams)
+		md.HeaderMD, md.TrailerMD = metadata.Join(md.HeaderMD, stream.Header()), metadata.Join(md.TrailerMD, stream.Trailer())
+		annotatedContext = runtime.NewServerMetadataContext(annotatedContext, md)
+		if err != nil {
+			runtime.HTTPError(annotatedContext, mux, outboundMarshaler, w, req, err)
+			return
+		}
+		forward_Election_Campaign_0(annotatedContext, mux, outboundMarshaler, w, req, resp, mux.GetForwardResponseOptions()...)
+	})
+	mux.Handle(http.MethodPost, pattern_Election_Proclaim_0, func(w http.ResponseWriter, req *http.Request, pathParams map[string]string) {
+		ctx, cancel := context.WithCancel(req.Context())
+		defer cancel()
+		var stream runtime.ServerTransportStream
+		ctx = grpc.NewContextWithServerTransportStream(ctx, &stream)
+		inboundMarshaler, outboundMarshaler := runtime.MarshalerForRequest(mux, req)
+		annotatedContext, err := runtime.AnnotateIncomingContext(ctx, mux, req, "/v3electionpb.Election/Proclaim", runtime.WithHTTPPathPattern("/v3/election/proclaim"))
+		if err != nil {
+			runtime.HTTPError(ctx, mux, outboundMarshaler, w, req, err)
+			return
+		}
+		resp, md, err := local_request_Election_Proclaim_0(annotatedContext, inboundMarshaler, server, req, pathParams)
+		md.HeaderMD, md.TrailerMD = metadata.Join(md.HeaderMD, stream.Header()), metadata.Join(md.TrailerMD, stream.Trailer())
+		annotatedContext = runtime.NewServerMetadataContext(annotatedContext, md)
+		if err != nil {
+			runtime.HTTPError(annotatedContext, mux, outboundMarshaler, w, req, err)
+			return
+		}
+		forward_Election_Proclaim_0(annotatedContext, mux, outboundMarshaler, w, req, resp, mux.GetForwardResponseOptions()...)
+	})
+	mux.Handle(http.MethodPost, pattern_Election_Leader_0, func(w http.ResponseWriter, req *http.Request, pathParams map[string]string) {
+		ctx, cancel := context.WithCancel(req.Context())
+		defer cancel()
+		var stream runtime.ServerTransportStream
+		ctx = grpc.NewContextWithServerTransportStream(ctx, &stream)
+		inboundMarshaler, outboundMarshaler := runtime.MarshalerForRequest(mux, req)
+		annotatedContext, err := runtime.AnnotateIncomingContext(ctx, mux, req, "/v3electionpb.Election/Leader", runtime.WithHTTPPathPattern("/v3/election/leader"))
+		if err != nil {
+			runtime.HTTPError(ctx, mux, outboundMarshaler, w, req, err)
+			return
+		}
+		resp, md, err := local_request_Election_Leader_0(annotatedContext, inboundMarshaler, server, req, pathParams)
+		md.HeaderMD, md.TrailerMD = metadata.Join(md.HeaderMD, stream.Header()), metadata.Join(md.TrailerMD, stream.Trailer())
+		annotatedContext = runtime.NewServerMetadataContext(annotatedContext, md)
+		if err != nil {
+			runtime.HTTPError(annotatedContext, mux, outboundMarshaler, w, req, err)
+			return
+		}
+		forward_Election_Leader_0(annotatedContext, mux, outboundMarshaler, w, req, resp, mux.GetForwardResponseOptions()...)
+	})
+
+	mux.Handle(http.MethodPost, pattern_Election_Observe_0, func(w http.ResponseWriter, req *http.Request, pathParams map[string]string) {
+		err := status.Error(codes.Unimplemented, "streaming calls are not yet supported in the in-process transport")
+		_, outboundMarshaler := runtime.MarshalerForRequest(mux, req)
+		runtime.HTTPError(ctx, mux, outboundMarshaler, w, req, err)
+		return
+	})
+	mux.Handle(http.MethodPost, pattern_Election_Resign_0, func(w http.ResponseWriter, req *http.Request, pathParams map[string]string) {
+		ctx, cancel := context.WithCancel(req.Context())
+		defer cancel()
+		var stream runtime.ServerTransportStream
+		ctx = grpc.NewContextWithServerTransportStream(ctx, &stream)
+		inboundMarshaler, outboundMarshaler := runtime.MarshalerForRequest(mux, req)
+		annotatedContext, err := runtime.AnnotateIncomingContext(ctx, mux, req, "/v3electionpb.Election/Resign", runtime.WithHTTPPathPattern("/v3/election/resign"))
+		if err != nil {
+			runtime.HTTPError(ctx, mux, outboundMarshaler, w, req, err)
+			return
+		}
+		resp, md, err := local_request_Election_Resign_0(annotatedContext, inboundMarshaler, server, req, pathParams)
+		md.HeaderMD, md.TrailerMD = metadata.Join(md.HeaderMD, stream.Header()), metadata.Join(md.TrailerMD, stream.Trailer())
+		annotatedContext = runtime.NewServerMetadataContext(annotatedContext, md)
+		if err != nil {
+			runtime.HTTPError(annotatedContext, mux, outboundMarshaler, w, req, err)
+			return
+		}
+		forward_Election_Resign_0(annotatedContext, mux, outboundMarshaler, w, req, resp, mux.GetForwardResponseOptions()...)
+	})
+
+	return nil
+}
+
+// RegisterElectionHandlerFromEndpoint is same as RegisterElectionHandler but
+// automatically dials to "endpoint" and closes the connection when "ctx" gets done.
+func RegisterElectionHandlerFromEndpoint(ctx context.Context, mux *runtime.ServeMux, endpoint string, opts []grpc.DialOption) (err error) {
+	conn, err := grpc.NewClient(endpoint, opts...)
+	if err != nil {
+		return err
+	}
+	defer func() {
+		if err != nil {
+			if cerr := conn.Close(); cerr != nil {
+				grpclog.Errorf("Failed to close conn to %s: %v", endpoint, cerr)
+			}
+			return
+		}
+		go func() {
+			<-ctx.Done()
+			if cerr := conn.Close(); cerr != nil {
+				grpclog.Errorf("Failed to close conn to %s: %v", endpoint, cerr)
+			}
+		}()
+	}()
+	return RegisterElectionHandler(ctx, mux, conn)
+}
+
+// RegisterElectionHandler registers the http handlers for service Election to "mux".
+// The handlers forward requests to the grpc endpoint over "conn".
+func RegisterElectionHandler(ctx context.Context, mux *runtime.ServeMux, conn *grpc.ClientConn) error {
+	return RegisterElectionHandlerClient(ctx, mux, v3electionpb.NewElectionClient(conn))
+}
+
+// v3electionpb.RegisterElectionHandlerClient registers the http handlers for service Election
+// to "mux". The handlers forward requests to the grpc endpoint over the given implementation of "ElectionClient".
+// Note: the gRPC framework executes interceptors within the gRPC handler. If the passed in "ElectionClient"
+// doesn't go through the normal gRPC flow (creating a gRPC client etc.) then it will be up to the passed in
+// "ElectionClient" to call the correct interceptors. This client ignores the HTTP middlewares.
+func RegisterElectionHandlerClient(ctx context.Context, mux *runtime.ServeMux, client v3electionpb.ElectionClient) error {
+	mux.Handle(http.MethodPost, pattern_Election_Campaign_0, func(w http.ResponseWriter, req *http.Request, pathParams map[string]string) {
+		ctx, cancel := context.WithCancel(req.Context())
+		defer cancel()
+		inboundMarshaler, outboundMarshaler := runtime.MarshalerForRequest(mux, req)
+		annotatedContext, err := runtime.AnnotateContext(ctx, mux, req, "/v3electionpb.Election/Campaign", runtime.WithHTTPPathPattern("/v3/election/campaign"))
+		if err != nil {
+			runtime.HTTPError(ctx, mux, outboundMarshaler, w, req, err)
+			return
+		}
+		resp, md, err := request_Election_Campaign_0(annotatedContext, inboundMarshaler, client, req, pathParams)
+		annotatedContext = runtime.NewServerMetadataContext(annotatedContext, md)
+		if err != nil {
+			runtime.HTTPError(annotatedContext, mux, outboundMarshaler, w, req, err)
+			return
+		}
+		forward_Election_Campaign_0(annotatedContext, mux, outboundMarshaler, w, req, resp, mux.GetForwardResponseOptions()...)
+	})
+	mux.Handle(http.MethodPost, pattern_Election_Proclaim_0, func(w http.ResponseWriter, req *http.Request, pathParams map[string]string) {
+		ctx, cancel := context.WithCancel(req.Context())
+		defer cancel()
+		inboundMarshaler, outboundMarshaler := runtime.MarshalerForRequest(mux, req)
+		annotatedContext, err := runtime.AnnotateContext(ctx, mux, req, "/v3electionpb.Election/Proclaim", runtime.WithHTTPPathPattern("/v3/election/proclaim"))
+		if err != nil {
+			runtime.HTTPError(ctx, mux, outboundMarshaler, w, req, err)
+			return
+		}
+		resp, md, err := request_Election_Proclaim_0(annotatedContext, inboundMarshaler, client, req, pathParams)
+		annotatedContext = runtime.NewServerMetadataContext(annotatedContext, md)
+		if err != nil {
+			runtime.HTTPError(annotatedContext, mux, outboundMarshaler, w, req, err)
+			return
+		}
+		forward_Election_Proclaim_0(annotatedContext, mux, outboundMarshaler, w, req, resp, mux.GetForwardResponseOptions()...)
+	})
+	mux.Handle(http.MethodPost, pattern_Election_Leader_0, func(w http.ResponseWriter, req *http.Request, pathParams map[string]string) {
+		ctx, cancel := context.WithCancel(req.Context())
+		defer cancel()
+		inboundMarshaler, outboundMarshaler := runtime.MarshalerForRequest(mux, req)
+		annotatedContext, err := runtime.AnnotateContext(ctx, mux, req, "/v3electionpb.Election/Leader", runtime.WithHTTPPathPattern("/v3/election/leader"))
+		if err != nil {
+			runtime.HTTPError(ctx, mux, outboundMarshaler, w, req, err)
+			return
+		}
+		resp, md, err := request_Election_Leader_0(annotatedContext, inboundMarshaler, client, req, pathParams)
+		annotatedContext = runtime.NewServerMetadataContext(annotatedContext, md)
+		if err != nil {
+			runtime.HTTPError(annotatedContext, mux, outboundMarshaler, w, req, err)
+			return
+		}
+		forward_Election_Leader_0(annotatedContext, mux, outboundMarshaler, w, req, resp, mux.GetForwardResponseOptions()...)
+	})
+	mux.Handle(http.MethodPost, pattern_Election_Observe_0, func(w http.ResponseWriter, req *http.Request, pathParams map[string]string) {
+		ctx, cancel := context.WithCancel(req.Context())
+		defer cancel()
+		inboundMarshaler, outboundMarshaler := runtime.MarshalerForRequest(mux, req)
+		annotatedContext, err := runtime.AnnotateContext(ctx, mux, req, "/v3electionpb.Election/Observe", runtime.WithHTTPPathPattern("/v3/election/observe"))
+		if err != nil {
+			runtime.HTTPError(ctx, mux, outboundMarshaler, w, req, err)
+			return
+		}
+		resp, md, err := request_Election_Observe_0(annotatedContext, inboundMarshaler, client, req, pathParams)
+		annotatedContext = runtime.NewServerMetadataContext(annotatedContext, md)
+		if err != nil {
+			runtime.HTTPError(annotatedContext, mux, outboundMarshaler, w, req, err)
+			return
+		}
+		forward_Election_Observe_0(annotatedContext, mux, outboundMarshaler, w, req, func() (proto.Message, error) {
+			m1, err := resp.Recv()
+			return protov1.MessageV2(m1), err
+		}, mux.GetForwardResponseOptions()...)
+	})
+	mux.Handle(http.MethodPost, pattern_Election_Resign_0, func(w http.ResponseWriter, req *http.Request, pathParams map[string]string) {
+		ctx, cancel := context.WithCancel(req.Context())
+		defer cancel()
+		inboundMarshaler, outboundMarshaler := runtime.MarshalerForRequest(mux, req)
+		annotatedContext, err := runtime.AnnotateContext(ctx, mux, req, "/v3electionpb.Election/Resign", runtime.WithHTTPPathPattern("/v3/election/resign"))
+		if err != nil {
+			runtime.HTTPError(ctx, mux, outboundMarshaler, w, req, err)
+			return
+		}
+		resp, md, err := request_Election_Resign_0(annotatedContext, inboundMarshaler, client, req, pathParams)
+		annotatedContext = runtime.NewServerMetadataContext(annotatedContext, md)
+		if err != nil {
+			runtime.HTTPError(annotatedContext, mux, outboundMarshaler, w, req, err)
+			return
+		}
+		forward_Election_Resign_0(annotatedContext, mux, outboundMarshaler, w, req, resp, mux.GetForwardResponseOptions()...)
+	})
+	return nil
+}
+
+var (
+	pattern_Election_Campaign_0 = runtime.MustPattern(runtime.NewPattern(1, []int{2, 0, 2, 1, 2, 2}, []string{"v3", "election", "campaign"}, ""))
+	pattern_Election_Proclaim_0 = runtime.MustPattern(runtime.NewPattern(1, []int{2, 0, 2, 1, 2, 2}, []string{"v3", "election", "proclaim"}, ""))
+	pattern_Election_Leader_0   = runtime.MustPattern(runtime.NewPattern(1, []int{2, 0, 2, 1, 2, 2}, []string{"v3", "election", "leader"}, ""))
+	pattern_Election_Observe_0  = runtime.MustPattern(runtime.NewPattern(1, []int{2, 0, 2, 1, 2, 2}, []string{"v3", "election", "observe"}, ""))
+	pattern_Election_Resign_0   = runtime.MustPattern(runtime.NewPattern(1, []int{2, 0, 2, 1, 2, 2}, []string{"v3", "election", "resign"}, ""))
+)
+
+var (
+	forward_Election_Campaign_0 = runtime.ForwardResponseMessage
+	forward_Election_Proclaim_0 = runtime.ForwardResponseMessage
+	forward_Election_Leader_0   = runtime.ForwardResponseMessage
+	forward_Election_Observe_0  = runtime.ForwardResponseStream
+	forward_Election_Resign_0   = runtime.ForwardResponseMessage
+)
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3election/v3electionpb/v3election.pb.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3election/v3electionpb/v3election.pb.go
new file mode 100644
index 0000000..02369cd
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3election/v3electionpb/v3election.pb.go
@@ -0,0 +1,2542 @@
+// Code generated by protoc-gen-gogo. DO NOT EDIT.
+// source: v3election.proto
+
+package v3electionpb
+
+import (
+	context "context"
+	fmt "fmt"
+	io "io"
+	math "math"
+	math_bits "math/bits"
+
+	_ "github.com/gogo/protobuf/gogoproto"
+	proto "github.com/golang/protobuf/proto"
+	etcdserverpb "go.etcd.io/etcd/api/v3/etcdserverpb"
+	mvccpb "go.etcd.io/etcd/api/v3/mvccpb"
+	_ "google.golang.org/genproto/googleapis/api/annotations"
+	grpc "google.golang.org/grpc"
+	codes "google.golang.org/grpc/codes"
+	status "google.golang.org/grpc/status"
+)
+
+// Reference imports to suppress errors if they are not otherwise used.
+var _ = proto.Marshal
+var _ = fmt.Errorf
+var _ = math.Inf
+
+// This is a compile-time assertion to ensure that this generated file
+// is compatible with the proto package it is being compiled against.
+// A compilation error at this line likely means your copy of the
+// proto package needs to be updated.
+const _ = proto.ProtoPackageIsVersion3 // please upgrade the proto package
+
+type CampaignRequest struct {
+	// name is the election's identifier for the campaign.
+	Name []byte `protobuf:"bytes,1,opt,name=name,proto3" json:"name,omitempty"`
+	// lease is the ID of the lease attached to leadership of the election. If the
+	// lease expires or is revoked before resigning leadership, then the
+	// leadership is transferred to the next campaigner, if any.
+	Lease int64 `protobuf:"varint,2,opt,name=lease,proto3" json:"lease,omitempty"`
+	// value is the initial proclaimed value set when the campaigner wins the
+	// election.
+	Value                []byte   `protobuf:"bytes,3,opt,name=value,proto3" json:"value,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
+}
+
+func (m *CampaignRequest) Reset()         { *m = CampaignRequest{} }
+func (m *CampaignRequest) String() string { return proto.CompactTextString(m) }
+func (*CampaignRequest) ProtoMessage()    {}
+func (*CampaignRequest) Descriptor() ([]byte, []int) {
+	return fileDescriptor_c9b1f26cc432a035, []int{0}
+}
+func (m *CampaignRequest) XXX_Unmarshal(b []byte) error {
+	return m.Unmarshal(b)
+}
+func (m *CampaignRequest) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	if deterministic {
+		return xxx_messageInfo_CampaignRequest.Marshal(b, m, deterministic)
+	} else {
+		b = b[:cap(b)]
+		n, err := m.MarshalToSizedBuffer(b)
+		if err != nil {
+			return nil, err
+		}
+		return b[:n], nil
+	}
+}
+func (m *CampaignRequest) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_CampaignRequest.Merge(m, src)
+}
+func (m *CampaignRequest) XXX_Size() int {
+	return m.Size()
+}
+func (m *CampaignRequest) XXX_DiscardUnknown() {
+	xxx_messageInfo_CampaignRequest.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_CampaignRequest proto.InternalMessageInfo
+
+func (m *CampaignRequest) GetName() []byte {
+	if m != nil {
+		return m.Name
+	}
+	return nil
+}
+
+func (m *CampaignRequest) GetLease() int64 {
+	if m != nil {
+		return m.Lease
+	}
+	return 0
+}
+
+func (m *CampaignRequest) GetValue() []byte {
+	if m != nil {
+		return m.Value
+	}
+	return nil
+}
+
+type CampaignResponse struct {
+	Header *etcdserverpb.ResponseHeader `protobuf:"bytes,1,opt,name=header,proto3" json:"header,omitempty"`
+	// leader describes the resources used for holding leadereship of the election.
+	Leader               *LeaderKey `protobuf:"bytes,2,opt,name=leader,proto3" json:"leader,omitempty"`
+	XXX_NoUnkeyedLiteral struct{}   `json:"-"`
+	XXX_unrecognized     []byte     `json:"-"`
+	XXX_sizecache        int32      `json:"-"`
+}
+
+func (m *CampaignResponse) Reset()         { *m = CampaignResponse{} }
+func (m *CampaignResponse) String() string { return proto.CompactTextString(m) }
+func (*CampaignResponse) ProtoMessage()    {}
+func (*CampaignResponse) Descriptor() ([]byte, []int) {
+	return fileDescriptor_c9b1f26cc432a035, []int{1}
+}
+func (m *CampaignResponse) XXX_Unmarshal(b []byte) error {
+	return m.Unmarshal(b)
+}
+func (m *CampaignResponse) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	if deterministic {
+		return xxx_messageInfo_CampaignResponse.Marshal(b, m, deterministic)
+	} else {
+		b = b[:cap(b)]
+		n, err := m.MarshalToSizedBuffer(b)
+		if err != nil {
+			return nil, err
+		}
+		return b[:n], nil
+	}
+}
+func (m *CampaignResponse) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_CampaignResponse.Merge(m, src)
+}
+func (m *CampaignResponse) XXX_Size() int {
+	return m.Size()
+}
+func (m *CampaignResponse) XXX_DiscardUnknown() {
+	xxx_messageInfo_CampaignResponse.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_CampaignResponse proto.InternalMessageInfo
+
+func (m *CampaignResponse) GetHeader() *etcdserverpb.ResponseHeader {
+	if m != nil {
+		return m.Header
+	}
+	return nil
+}
+
+func (m *CampaignResponse) GetLeader() *LeaderKey {
+	if m != nil {
+		return m.Leader
+	}
+	return nil
+}
+
+type LeaderKey struct {
+	// name is the election identifier that corresponds to the leadership key.
+	Name []byte `protobuf:"bytes,1,opt,name=name,proto3" json:"name,omitempty"`
+	// key is an opaque key representing the ownership of the election. If the key
+	// is deleted, then leadership is lost.
+	Key []byte `protobuf:"bytes,2,opt,name=key,proto3" json:"key,omitempty"`
+	// rev is the creation revision of the key. It can be used to test for ownership
+	// of an election during transactions by testing the key's creation revision
+	// matches rev.
+	Rev int64 `protobuf:"varint,3,opt,name=rev,proto3" json:"rev,omitempty"`
+	// lease is the lease ID of the election leader.
+	Lease                int64    `protobuf:"varint,4,opt,name=lease,proto3" json:"lease,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
+}
+
+func (m *LeaderKey) Reset()         { *m = LeaderKey{} }
+func (m *LeaderKey) String() string { return proto.CompactTextString(m) }
+func (*LeaderKey) ProtoMessage()    {}
+func (*LeaderKey) Descriptor() ([]byte, []int) {
+	return fileDescriptor_c9b1f26cc432a035, []int{2}
+}
+func (m *LeaderKey) XXX_Unmarshal(b []byte) error {
+	return m.Unmarshal(b)
+}
+func (m *LeaderKey) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	if deterministic {
+		return xxx_messageInfo_LeaderKey.Marshal(b, m, deterministic)
+	} else {
+		b = b[:cap(b)]
+		n, err := m.MarshalToSizedBuffer(b)
+		if err != nil {
+			return nil, err
+		}
+		return b[:n], nil
+	}
+}
+func (m *LeaderKey) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_LeaderKey.Merge(m, src)
+}
+func (m *LeaderKey) XXX_Size() int {
+	return m.Size()
+}
+func (m *LeaderKey) XXX_DiscardUnknown() {
+	xxx_messageInfo_LeaderKey.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_LeaderKey proto.InternalMessageInfo
+
+func (m *LeaderKey) GetName() []byte {
+	if m != nil {
+		return m.Name
+	}
+	return nil
+}
+
+func (m *LeaderKey) GetKey() []byte {
+	if m != nil {
+		return m.Key
+	}
+	return nil
+}
+
+func (m *LeaderKey) GetRev() int64 {
+	if m != nil {
+		return m.Rev
+	}
+	return 0
+}
+
+func (m *LeaderKey) GetLease() int64 {
+	if m != nil {
+		return m.Lease
+	}
+	return 0
+}
+
+type LeaderRequest struct {
+	// name is the election identifier for the leadership information.
+	Name                 []byte   `protobuf:"bytes,1,opt,name=name,proto3" json:"name,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
+}
+
+func (m *LeaderRequest) Reset()         { *m = LeaderRequest{} }
+func (m *LeaderRequest) String() string { return proto.CompactTextString(m) }
+func (*LeaderRequest) ProtoMessage()    {}
+func (*LeaderRequest) Descriptor() ([]byte, []int) {
+	return fileDescriptor_c9b1f26cc432a035, []int{3}
+}
+func (m *LeaderRequest) XXX_Unmarshal(b []byte) error {
+	return m.Unmarshal(b)
+}
+func (m *LeaderRequest) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	if deterministic {
+		return xxx_messageInfo_LeaderRequest.Marshal(b, m, deterministic)
+	} else {
+		b = b[:cap(b)]
+		n, err := m.MarshalToSizedBuffer(b)
+		if err != nil {
+			return nil, err
+		}
+		return b[:n], nil
+	}
+}
+func (m *LeaderRequest) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_LeaderRequest.Merge(m, src)
+}
+func (m *LeaderRequest) XXX_Size() int {
+	return m.Size()
+}
+func (m *LeaderRequest) XXX_DiscardUnknown() {
+	xxx_messageInfo_LeaderRequest.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_LeaderRequest proto.InternalMessageInfo
+
+func (m *LeaderRequest) GetName() []byte {
+	if m != nil {
+		return m.Name
+	}
+	return nil
+}
+
+type LeaderResponse struct {
+	Header *etcdserverpb.ResponseHeader `protobuf:"bytes,1,opt,name=header,proto3" json:"header,omitempty"`
+	// kv is the key-value pair representing the latest leader update.
+	Kv                   *mvccpb.KeyValue `protobuf:"bytes,2,opt,name=kv,proto3" json:"kv,omitempty"`
+	XXX_NoUnkeyedLiteral struct{}         `json:"-"`
+	XXX_unrecognized     []byte           `json:"-"`
+	XXX_sizecache        int32            `json:"-"`
+}
+
+func (m *LeaderResponse) Reset()         { *m = LeaderResponse{} }
+func (m *LeaderResponse) String() string { return proto.CompactTextString(m) }
+func (*LeaderResponse) ProtoMessage()    {}
+func (*LeaderResponse) Descriptor() ([]byte, []int) {
+	return fileDescriptor_c9b1f26cc432a035, []int{4}
+}
+func (m *LeaderResponse) XXX_Unmarshal(b []byte) error {
+	return m.Unmarshal(b)
+}
+func (m *LeaderResponse) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	if deterministic {
+		return xxx_messageInfo_LeaderResponse.Marshal(b, m, deterministic)
+	} else {
+		b = b[:cap(b)]
+		n, err := m.MarshalToSizedBuffer(b)
+		if err != nil {
+			return nil, err
+		}
+		return b[:n], nil
+	}
+}
+func (m *LeaderResponse) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_LeaderResponse.Merge(m, src)
+}
+func (m *LeaderResponse) XXX_Size() int {
+	return m.Size()
+}
+func (m *LeaderResponse) XXX_DiscardUnknown() {
+	xxx_messageInfo_LeaderResponse.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_LeaderResponse proto.InternalMessageInfo
+
+func (m *LeaderResponse) GetHeader() *etcdserverpb.ResponseHeader {
+	if m != nil {
+		return m.Header
+	}
+	return nil
+}
+
+func (m *LeaderResponse) GetKv() *mvccpb.KeyValue {
+	if m != nil {
+		return m.Kv
+	}
+	return nil
+}
+
+type ResignRequest struct {
+	// leader is the leadership to relinquish by resignation.
+	Leader               *LeaderKey `protobuf:"bytes,1,opt,name=leader,proto3" json:"leader,omitempty"`
+	XXX_NoUnkeyedLiteral struct{}   `json:"-"`
+	XXX_unrecognized     []byte     `json:"-"`
+	XXX_sizecache        int32      `json:"-"`
+}
+
+func (m *ResignRequest) Reset()         { *m = ResignRequest{} }
+func (m *ResignRequest) String() string { return proto.CompactTextString(m) }
+func (*ResignRequest) ProtoMessage()    {}
+func (*ResignRequest) Descriptor() ([]byte, []int) {
+	return fileDescriptor_c9b1f26cc432a035, []int{5}
+}
+func (m *ResignRequest) XXX_Unmarshal(b []byte) error {
+	return m.Unmarshal(b)
+}
+func (m *ResignRequest) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	if deterministic {
+		return xxx_messageInfo_ResignRequest.Marshal(b, m, deterministic)
+	} else {
+		b = b[:cap(b)]
+		n, err := m.MarshalToSizedBuffer(b)
+		if err != nil {
+			return nil, err
+		}
+		return b[:n], nil
+	}
+}
+func (m *ResignRequest) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_ResignRequest.Merge(m, src)
+}
+func (m *ResignRequest) XXX_Size() int {
+	return m.Size()
+}
+func (m *ResignRequest) XXX_DiscardUnknown() {
+	xxx_messageInfo_ResignRequest.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_ResignRequest proto.InternalMessageInfo
+
+func (m *ResignRequest) GetLeader() *LeaderKey {
+	if m != nil {
+		return m.Leader
+	}
+	return nil
+}
+
+type ResignResponse struct {
+	Header               *etcdserverpb.ResponseHeader `protobuf:"bytes,1,opt,name=header,proto3" json:"header,omitempty"`
+	XXX_NoUnkeyedLiteral struct{}                     `json:"-"`
+	XXX_unrecognized     []byte                       `json:"-"`
+	XXX_sizecache        int32                        `json:"-"`
+}
+
+func (m *ResignResponse) Reset()         { *m = ResignResponse{} }
+func (m *ResignResponse) String() string { return proto.CompactTextString(m) }
+func (*ResignResponse) ProtoMessage()    {}
+func (*ResignResponse) Descriptor() ([]byte, []int) {
+	return fileDescriptor_c9b1f26cc432a035, []int{6}
+}
+func (m *ResignResponse) XXX_Unmarshal(b []byte) error {
+	return m.Unmarshal(b)
+}
+func (m *ResignResponse) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	if deterministic {
+		return xxx_messageInfo_ResignResponse.Marshal(b, m, deterministic)
+	} else {
+		b = b[:cap(b)]
+		n, err := m.MarshalToSizedBuffer(b)
+		if err != nil {
+			return nil, err
+		}
+		return b[:n], nil
+	}
+}
+func (m *ResignResponse) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_ResignResponse.Merge(m, src)
+}
+func (m *ResignResponse) XXX_Size() int {
+	return m.Size()
+}
+func (m *ResignResponse) XXX_DiscardUnknown() {
+	xxx_messageInfo_ResignResponse.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_ResignResponse proto.InternalMessageInfo
+
+func (m *ResignResponse) GetHeader() *etcdserverpb.ResponseHeader {
+	if m != nil {
+		return m.Header
+	}
+	return nil
+}
+
+type ProclaimRequest struct {
+	// leader is the leadership hold on the election.
+	Leader *LeaderKey `protobuf:"bytes,1,opt,name=leader,proto3" json:"leader,omitempty"`
+	// value is an update meant to overwrite the leader's current value.
+	Value                []byte   `protobuf:"bytes,2,opt,name=value,proto3" json:"value,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
+}
+
+func (m *ProclaimRequest) Reset()         { *m = ProclaimRequest{} }
+func (m *ProclaimRequest) String() string { return proto.CompactTextString(m) }
+func (*ProclaimRequest) ProtoMessage()    {}
+func (*ProclaimRequest) Descriptor() ([]byte, []int) {
+	return fileDescriptor_c9b1f26cc432a035, []int{7}
+}
+func (m *ProclaimRequest) XXX_Unmarshal(b []byte) error {
+	return m.Unmarshal(b)
+}
+func (m *ProclaimRequest) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	if deterministic {
+		return xxx_messageInfo_ProclaimRequest.Marshal(b, m, deterministic)
+	} else {
+		b = b[:cap(b)]
+		n, err := m.MarshalToSizedBuffer(b)
+		if err != nil {
+			return nil, err
+		}
+		return b[:n], nil
+	}
+}
+func (m *ProclaimRequest) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_ProclaimRequest.Merge(m, src)
+}
+func (m *ProclaimRequest) XXX_Size() int {
+	return m.Size()
+}
+func (m *ProclaimRequest) XXX_DiscardUnknown() {
+	xxx_messageInfo_ProclaimRequest.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_ProclaimRequest proto.InternalMessageInfo
+
+func (m *ProclaimRequest) GetLeader() *LeaderKey {
+	if m != nil {
+		return m.Leader
+	}
+	return nil
+}
+
+func (m *ProclaimRequest) GetValue() []byte {
+	if m != nil {
+		return m.Value
+	}
+	return nil
+}
+
+type ProclaimResponse struct {
+	Header               *etcdserverpb.ResponseHeader `protobuf:"bytes,1,opt,name=header,proto3" json:"header,omitempty"`
+	XXX_NoUnkeyedLiteral struct{}                     `json:"-"`
+	XXX_unrecognized     []byte                       `json:"-"`
+	XXX_sizecache        int32                        `json:"-"`
+}
+
+func (m *ProclaimResponse) Reset()         { *m = ProclaimResponse{} }
+func (m *ProclaimResponse) String() string { return proto.CompactTextString(m) }
+func (*ProclaimResponse) ProtoMessage()    {}
+func (*ProclaimResponse) Descriptor() ([]byte, []int) {
+	return fileDescriptor_c9b1f26cc432a035, []int{8}
+}
+func (m *ProclaimResponse) XXX_Unmarshal(b []byte) error {
+	return m.Unmarshal(b)
+}
+func (m *ProclaimResponse) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	if deterministic {
+		return xxx_messageInfo_ProclaimResponse.Marshal(b, m, deterministic)
+	} else {
+		b = b[:cap(b)]
+		n, err := m.MarshalToSizedBuffer(b)
+		if err != nil {
+			return nil, err
+		}
+		return b[:n], nil
+	}
+}
+func (m *ProclaimResponse) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_ProclaimResponse.Merge(m, src)
+}
+func (m *ProclaimResponse) XXX_Size() int {
+	return m.Size()
+}
+func (m *ProclaimResponse) XXX_DiscardUnknown() {
+	xxx_messageInfo_ProclaimResponse.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_ProclaimResponse proto.InternalMessageInfo
+
+func (m *ProclaimResponse) GetHeader() *etcdserverpb.ResponseHeader {
+	if m != nil {
+		return m.Header
+	}
+	return nil
+}
+
+func init() {
+	proto.RegisterType((*CampaignRequest)(nil), "v3electionpb.CampaignRequest")
+	proto.RegisterType((*CampaignResponse)(nil), "v3electionpb.CampaignResponse")
+	proto.RegisterType((*LeaderKey)(nil), "v3electionpb.LeaderKey")
+	proto.RegisterType((*LeaderRequest)(nil), "v3electionpb.LeaderRequest")
+	proto.RegisterType((*LeaderResponse)(nil), "v3electionpb.LeaderResponse")
+	proto.RegisterType((*ResignRequest)(nil), "v3electionpb.ResignRequest")
+	proto.RegisterType((*ResignResponse)(nil), "v3electionpb.ResignResponse")
+	proto.RegisterType((*ProclaimRequest)(nil), "v3electionpb.ProclaimRequest")
+	proto.RegisterType((*ProclaimResponse)(nil), "v3electionpb.ProclaimResponse")
+}
+
+func init() { proto.RegisterFile("v3election.proto", fileDescriptor_c9b1f26cc432a035) }
+
+var fileDescriptor_c9b1f26cc432a035 = []byte{
+	// 556 bytes of a gzipped FileDescriptorProto
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+	0x6e, 0x7c, 0x3c, 0xf5, 0xa5, 0x9e, 0x29, 0x77, 0x22, 0xf5, 0x63, 0xcb, 0xcc, 0x70, 0xe9, 0xf3,
+	0xab, 0x51, 0xd3, 0xaf, 0x69, 0xc1, 0x65, 0xe5, 0x12, 0xc6, 0x0d, 0xfd, 0xb4, 0x0e, 0xff, 0x06,
+	0x00, 0x00, 0xff, 0xff, 0xcd, 0x58, 0x82, 0xe2, 0xeb, 0x05, 0x00, 0x00,
+}
+
+// Reference imports to suppress errors if they are not otherwise used.
+var _ context.Context
+var _ grpc.ClientConn
+
+// This is a compile-time assertion to ensure that this generated file
+// is compatible with the grpc package it is being compiled against.
+const _ = grpc.SupportPackageIsVersion4
+
+// ElectionClient is the client API for Election service.
+//
+// For semantics around ctx use and closing/ending streaming RPCs, please refer to https://godoc.org/google.golang.org/grpc#ClientConn.NewStream.
+type ElectionClient interface {
+	// Campaign waits to acquire leadership in an election, returning a LeaderKey
+	// representing the leadership if successful. The LeaderKey can then be used
+	// to issue new values on the election, transactionally guard API requests on
+	// leadership still being held, and resign from the election.
+	Campaign(ctx context.Context, in *CampaignRequest, opts ...grpc.CallOption) (*CampaignResponse, error)
+	// Proclaim updates the leader's posted value with a new value.
+	Proclaim(ctx context.Context, in *ProclaimRequest, opts ...grpc.CallOption) (*ProclaimResponse, error)
+	// Leader returns the current election proclamation, if any.
+	Leader(ctx context.Context, in *LeaderRequest, opts ...grpc.CallOption) (*LeaderResponse, error)
+	// Observe streams election proclamations in-order as made by the election's
+	// elected leaders.
+	Observe(ctx context.Context, in *LeaderRequest, opts ...grpc.CallOption) (Election_ObserveClient, error)
+	// Resign releases election leadership so other campaigners may acquire
+	// leadership on the election.
+	Resign(ctx context.Context, in *ResignRequest, opts ...grpc.CallOption) (*ResignResponse, error)
+}
+
+type electionClient struct {
+	cc *grpc.ClientConn
+}
+
+func NewElectionClient(cc *grpc.ClientConn) ElectionClient {
+	return &electionClient{cc}
+}
+
+func (c *electionClient) Campaign(ctx context.Context, in *CampaignRequest, opts ...grpc.CallOption) (*CampaignResponse, error) {
+	out := new(CampaignResponse)
+	err := c.cc.Invoke(ctx, "/v3electionpb.Election/Campaign", in, out, opts...)
+	if err != nil {
+		return nil, err
+	}
+	return out, nil
+}
+
+func (c *electionClient) Proclaim(ctx context.Context, in *ProclaimRequest, opts ...grpc.CallOption) (*ProclaimResponse, error) {
+	out := new(ProclaimResponse)
+	err := c.cc.Invoke(ctx, "/v3electionpb.Election/Proclaim", in, out, opts...)
+	if err != nil {
+		return nil, err
+	}
+	return out, nil
+}
+
+func (c *electionClient) Leader(ctx context.Context, in *LeaderRequest, opts ...grpc.CallOption) (*LeaderResponse, error) {
+	out := new(LeaderResponse)
+	err := c.cc.Invoke(ctx, "/v3electionpb.Election/Leader", in, out, opts...)
+	if err != nil {
+		return nil, err
+	}
+	return out, nil
+}
+
+func (c *electionClient) Observe(ctx context.Context, in *LeaderRequest, opts ...grpc.CallOption) (Election_ObserveClient, error) {
+	stream, err := c.cc.NewStream(ctx, &_Election_serviceDesc.Streams[0], "/v3electionpb.Election/Observe", opts...)
+	if err != nil {
+		return nil, err
+	}
+	x := &electionObserveClient{stream}
+	if err := x.ClientStream.SendMsg(in); err != nil {
+		return nil, err
+	}
+	if err := x.ClientStream.CloseSend(); err != nil {
+		return nil, err
+	}
+	return x, nil
+}
+
+type Election_ObserveClient interface {
+	Recv() (*LeaderResponse, error)
+	grpc.ClientStream
+}
+
+type electionObserveClient struct {
+	grpc.ClientStream
+}
+
+func (x *electionObserveClient) Recv() (*LeaderResponse, error) {
+	m := new(LeaderResponse)
+	if err := x.ClientStream.RecvMsg(m); err != nil {
+		return nil, err
+	}
+	return m, nil
+}
+
+func (c *electionClient) Resign(ctx context.Context, in *ResignRequest, opts ...grpc.CallOption) (*ResignResponse, error) {
+	out := new(ResignResponse)
+	err := c.cc.Invoke(ctx, "/v3electionpb.Election/Resign", in, out, opts...)
+	if err != nil {
+		return nil, err
+	}
+	return out, nil
+}
+
+// ElectionServer is the server API for Election service.
+type ElectionServer interface {
+	// Campaign waits to acquire leadership in an election, returning a LeaderKey
+	// representing the leadership if successful. The LeaderKey can then be used
+	// to issue new values on the election, transactionally guard API requests on
+	// leadership still being held, and resign from the election.
+	Campaign(context.Context, *CampaignRequest) (*CampaignResponse, error)
+	// Proclaim updates the leader's posted value with a new value.
+	Proclaim(context.Context, *ProclaimRequest) (*ProclaimResponse, error)
+	// Leader returns the current election proclamation, if any.
+	Leader(context.Context, *LeaderRequest) (*LeaderResponse, error)
+	// Observe streams election proclamations in-order as made by the election's
+	// elected leaders.
+	Observe(*LeaderRequest, Election_ObserveServer) error
+	// Resign releases election leadership so other campaigners may acquire
+	// leadership on the election.
+	Resign(context.Context, *ResignRequest) (*ResignResponse, error)
+}
+
+// UnimplementedElectionServer can be embedded to have forward compatible implementations.
+type UnimplementedElectionServer struct {
+}
+
+func (*UnimplementedElectionServer) Campaign(ctx context.Context, req *CampaignRequest) (*CampaignResponse, error) {
+	return nil, status.Errorf(codes.Unimplemented, "method Campaign not implemented")
+}
+func (*UnimplementedElectionServer) Proclaim(ctx context.Context, req *ProclaimRequest) (*ProclaimResponse, error) {
+	return nil, status.Errorf(codes.Unimplemented, "method Proclaim not implemented")
+}
+func (*UnimplementedElectionServer) Leader(ctx context.Context, req *LeaderRequest) (*LeaderResponse, error) {
+	return nil, status.Errorf(codes.Unimplemented, "method Leader not implemented")
+}
+func (*UnimplementedElectionServer) Observe(req *LeaderRequest, srv Election_ObserveServer) error {
+	return status.Errorf(codes.Unimplemented, "method Observe not implemented")
+}
+func (*UnimplementedElectionServer) Resign(ctx context.Context, req *ResignRequest) (*ResignResponse, error) {
+	return nil, status.Errorf(codes.Unimplemented, "method Resign not implemented")
+}
+
+func RegisterElectionServer(s *grpc.Server, srv ElectionServer) {
+	s.RegisterService(&_Election_serviceDesc, srv)
+}
+
+func _Election_Campaign_Handler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor grpc.UnaryServerInterceptor) (interface{}, error) {
+	in := new(CampaignRequest)
+	if err := dec(in); err != nil {
+		return nil, err
+	}
+	if interceptor == nil {
+		return srv.(ElectionServer).Campaign(ctx, in)
+	}
+	info := &grpc.UnaryServerInfo{
+		Server:     srv,
+		FullMethod: "/v3electionpb.Election/Campaign",
+	}
+	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
+		return srv.(ElectionServer).Campaign(ctx, req.(*CampaignRequest))
+	}
+	return interceptor(ctx, in, info, handler)
+}
+
+func _Election_Proclaim_Handler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor grpc.UnaryServerInterceptor) (interface{}, error) {
+	in := new(ProclaimRequest)
+	if err := dec(in); err != nil {
+		return nil, err
+	}
+	if interceptor == nil {
+		return srv.(ElectionServer).Proclaim(ctx, in)
+	}
+	info := &grpc.UnaryServerInfo{
+		Server:     srv,
+		FullMethod: "/v3electionpb.Election/Proclaim",
+	}
+	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
+		return srv.(ElectionServer).Proclaim(ctx, req.(*ProclaimRequest))
+	}
+	return interceptor(ctx, in, info, handler)
+}
+
+func _Election_Leader_Handler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor grpc.UnaryServerInterceptor) (interface{}, error) {
+	in := new(LeaderRequest)
+	if err := dec(in); err != nil {
+		return nil, err
+	}
+	if interceptor == nil {
+		return srv.(ElectionServer).Leader(ctx, in)
+	}
+	info := &grpc.UnaryServerInfo{
+		Server:     srv,
+		FullMethod: "/v3electionpb.Election/Leader",
+	}
+	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
+		return srv.(ElectionServer).Leader(ctx, req.(*LeaderRequest))
+	}
+	return interceptor(ctx, in, info, handler)
+}
+
+func _Election_Observe_Handler(srv interface{}, stream grpc.ServerStream) error {
+	m := new(LeaderRequest)
+	if err := stream.RecvMsg(m); err != nil {
+		return err
+	}
+	return srv.(ElectionServer).Observe(m, &electionObserveServer{stream})
+}
+
+type Election_ObserveServer interface {
+	Send(*LeaderResponse) error
+	grpc.ServerStream
+}
+
+type electionObserveServer struct {
+	grpc.ServerStream
+}
+
+func (x *electionObserveServer) Send(m *LeaderResponse) error {
+	return x.ServerStream.SendMsg(m)
+}
+
+func _Election_Resign_Handler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor grpc.UnaryServerInterceptor) (interface{}, error) {
+	in := new(ResignRequest)
+	if err := dec(in); err != nil {
+		return nil, err
+	}
+	if interceptor == nil {
+		return srv.(ElectionServer).Resign(ctx, in)
+	}
+	info := &grpc.UnaryServerInfo{
+		Server:     srv,
+		FullMethod: "/v3electionpb.Election/Resign",
+	}
+	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
+		return srv.(ElectionServer).Resign(ctx, req.(*ResignRequest))
+	}
+	return interceptor(ctx, in, info, handler)
+}
+
+var _Election_serviceDesc = grpc.ServiceDesc{
+	ServiceName: "v3electionpb.Election",
+	HandlerType: (*ElectionServer)(nil),
+	Methods: []grpc.MethodDesc{
+		{
+			MethodName: "Campaign",
+			Handler:    _Election_Campaign_Handler,
+		},
+		{
+			MethodName: "Proclaim",
+			Handler:    _Election_Proclaim_Handler,
+		},
+		{
+			MethodName: "Leader",
+			Handler:    _Election_Leader_Handler,
+		},
+		{
+			MethodName: "Resign",
+			Handler:    _Election_Resign_Handler,
+		},
+	},
+	Streams: []grpc.StreamDesc{
+		{
+			StreamName:    "Observe",
+			Handler:       _Election_Observe_Handler,
+			ServerStreams: true,
+		},
+	},
+	Metadata: "v3election.proto",
+}
+
+func (m *CampaignRequest) Marshal() (dAtA []byte, err error) {
+	size := m.Size()
+	dAtA = make([]byte, size)
+	n, err := m.MarshalToSizedBuffer(dAtA[:size])
+	if err != nil {
+		return nil, err
+	}
+	return dAtA[:n], nil
+}
+
+func (m *CampaignRequest) MarshalTo(dAtA []byte) (int, error) {
+	size := m.Size()
+	return m.MarshalToSizedBuffer(dAtA[:size])
+}
+
+func (m *CampaignRequest) MarshalToSizedBuffer(dAtA []byte) (int, error) {
+	i := len(dAtA)
+	_ = i
+	var l int
+	_ = l
+	if m.XXX_unrecognized != nil {
+		i -= len(m.XXX_unrecognized)
+		copy(dAtA[i:], m.XXX_unrecognized)
+	}
+	if len(m.Value) > 0 {
+		i -= len(m.Value)
+		copy(dAtA[i:], m.Value)
+		i = encodeVarintV3Election(dAtA, i, uint64(len(m.Value)))
+		i--
+		dAtA[i] = 0x1a
+	}
+	if m.Lease != 0 {
+		i = encodeVarintV3Election(dAtA, i, uint64(m.Lease))
+		i--
+		dAtA[i] = 0x10
+	}
+	if len(m.Name) > 0 {
+		i -= len(m.Name)
+		copy(dAtA[i:], m.Name)
+		i = encodeVarintV3Election(dAtA, i, uint64(len(m.Name)))
+		i--
+		dAtA[i] = 0xa
+	}
+	return len(dAtA) - i, nil
+}
+
+func (m *CampaignResponse) Marshal() (dAtA []byte, err error) {
+	size := m.Size()
+	dAtA = make([]byte, size)
+	n, err := m.MarshalToSizedBuffer(dAtA[:size])
+	if err != nil {
+		return nil, err
+	}
+	return dAtA[:n], nil
+}
+
+func (m *CampaignResponse) MarshalTo(dAtA []byte) (int, error) {
+	size := m.Size()
+	return m.MarshalToSizedBuffer(dAtA[:size])
+}
+
+func (m *CampaignResponse) MarshalToSizedBuffer(dAtA []byte) (int, error) {
+	i := len(dAtA)
+	_ = i
+	var l int
+	_ = l
+	if m.XXX_unrecognized != nil {
+		i -= len(m.XXX_unrecognized)
+		copy(dAtA[i:], m.XXX_unrecognized)
+	}
+	if m.Leader != nil {
+		{
+			size, err := m.Leader.MarshalToSizedBuffer(dAtA[:i])
+			if err != nil {
+				return 0, err
+			}
+			i -= size
+			i = encodeVarintV3Election(dAtA, i, uint64(size))
+		}
+		i--
+		dAtA[i] = 0x12
+	}
+	if m.Header != nil {
+		{
+			size, err := m.Header.MarshalToSizedBuffer(dAtA[:i])
+			if err != nil {
+				return 0, err
+			}
+			i -= size
+			i = encodeVarintV3Election(dAtA, i, uint64(size))
+		}
+		i--
+		dAtA[i] = 0xa
+	}
+	return len(dAtA) - i, nil
+}
+
+func (m *LeaderKey) Marshal() (dAtA []byte, err error) {
+	size := m.Size()
+	dAtA = make([]byte, size)
+	n, err := m.MarshalToSizedBuffer(dAtA[:size])
+	if err != nil {
+		return nil, err
+	}
+	return dAtA[:n], nil
+}
+
+func (m *LeaderKey) MarshalTo(dAtA []byte) (int, error) {
+	size := m.Size()
+	return m.MarshalToSizedBuffer(dAtA[:size])
+}
+
+func (m *LeaderKey) MarshalToSizedBuffer(dAtA []byte) (int, error) {
+	i := len(dAtA)
+	_ = i
+	var l int
+	_ = l
+	if m.XXX_unrecognized != nil {
+		i -= len(m.XXX_unrecognized)
+		copy(dAtA[i:], m.XXX_unrecognized)
+	}
+	if m.Lease != 0 {
+		i = encodeVarintV3Election(dAtA, i, uint64(m.Lease))
+		i--
+		dAtA[i] = 0x20
+	}
+	if m.Rev != 0 {
+		i = encodeVarintV3Election(dAtA, i, uint64(m.Rev))
+		i--
+		dAtA[i] = 0x18
+	}
+	if len(m.Key) > 0 {
+		i -= len(m.Key)
+		copy(dAtA[i:], m.Key)
+		i = encodeVarintV3Election(dAtA, i, uint64(len(m.Key)))
+		i--
+		dAtA[i] = 0x12
+	}
+	if len(m.Name) > 0 {
+		i -= len(m.Name)
+		copy(dAtA[i:], m.Name)
+		i = encodeVarintV3Election(dAtA, i, uint64(len(m.Name)))
+		i--
+		dAtA[i] = 0xa
+	}
+	return len(dAtA) - i, nil
+}
+
+func (m *LeaderRequest) Marshal() (dAtA []byte, err error) {
+	size := m.Size()
+	dAtA = make([]byte, size)
+	n, err := m.MarshalToSizedBuffer(dAtA[:size])
+	if err != nil {
+		return nil, err
+	}
+	return dAtA[:n], nil
+}
+
+func (m *LeaderRequest) MarshalTo(dAtA []byte) (int, error) {
+	size := m.Size()
+	return m.MarshalToSizedBuffer(dAtA[:size])
+}
+
+func (m *LeaderRequest) MarshalToSizedBuffer(dAtA []byte) (int, error) {
+	i := len(dAtA)
+	_ = i
+	var l int
+	_ = l
+	if m.XXX_unrecognized != nil {
+		i -= len(m.XXX_unrecognized)
+		copy(dAtA[i:], m.XXX_unrecognized)
+	}
+	if len(m.Name) > 0 {
+		i -= len(m.Name)
+		copy(dAtA[i:], m.Name)
+		i = encodeVarintV3Election(dAtA, i, uint64(len(m.Name)))
+		i--
+		dAtA[i] = 0xa
+	}
+	return len(dAtA) - i, nil
+}
+
+func (m *LeaderResponse) Marshal() (dAtA []byte, err error) {
+	size := m.Size()
+	dAtA = make([]byte, size)
+	n, err := m.MarshalToSizedBuffer(dAtA[:size])
+	if err != nil {
+		return nil, err
+	}
+	return dAtA[:n], nil
+}
+
+func (m *LeaderResponse) MarshalTo(dAtA []byte) (int, error) {
+	size := m.Size()
+	return m.MarshalToSizedBuffer(dAtA[:size])
+}
+
+func (m *LeaderResponse) MarshalToSizedBuffer(dAtA []byte) (int, error) {
+	i := len(dAtA)
+	_ = i
+	var l int
+	_ = l
+	if m.XXX_unrecognized != nil {
+		i -= len(m.XXX_unrecognized)
+		copy(dAtA[i:], m.XXX_unrecognized)
+	}
+	if m.Kv != nil {
+		{
+			size, err := m.Kv.MarshalToSizedBuffer(dAtA[:i])
+			if err != nil {
+				return 0, err
+			}
+			i -= size
+			i = encodeVarintV3Election(dAtA, i, uint64(size))
+		}
+		i--
+		dAtA[i] = 0x12
+	}
+	if m.Header != nil {
+		{
+			size, err := m.Header.MarshalToSizedBuffer(dAtA[:i])
+			if err != nil {
+				return 0, err
+			}
+			i -= size
+			i = encodeVarintV3Election(dAtA, i, uint64(size))
+		}
+		i--
+		dAtA[i] = 0xa
+	}
+	return len(dAtA) - i, nil
+}
+
+func (m *ResignRequest) Marshal() (dAtA []byte, err error) {
+	size := m.Size()
+	dAtA = make([]byte, size)
+	n, err := m.MarshalToSizedBuffer(dAtA[:size])
+	if err != nil {
+		return nil, err
+	}
+	return dAtA[:n], nil
+}
+
+func (m *ResignRequest) MarshalTo(dAtA []byte) (int, error) {
+	size := m.Size()
+	return m.MarshalToSizedBuffer(dAtA[:size])
+}
+
+func (m *ResignRequest) MarshalToSizedBuffer(dAtA []byte) (int, error) {
+	i := len(dAtA)
+	_ = i
+	var l int
+	_ = l
+	if m.XXX_unrecognized != nil {
+		i -= len(m.XXX_unrecognized)
+		copy(dAtA[i:], m.XXX_unrecognized)
+	}
+	if m.Leader != nil {
+		{
+			size, err := m.Leader.MarshalToSizedBuffer(dAtA[:i])
+			if err != nil {
+				return 0, err
+			}
+			i -= size
+			i = encodeVarintV3Election(dAtA, i, uint64(size))
+		}
+		i--
+		dAtA[i] = 0xa
+	}
+	return len(dAtA) - i, nil
+}
+
+func (m *ResignResponse) Marshal() (dAtA []byte, err error) {
+	size := m.Size()
+	dAtA = make([]byte, size)
+	n, err := m.MarshalToSizedBuffer(dAtA[:size])
+	if err != nil {
+		return nil, err
+	}
+	return dAtA[:n], nil
+}
+
+func (m *ResignResponse) MarshalTo(dAtA []byte) (int, error) {
+	size := m.Size()
+	return m.MarshalToSizedBuffer(dAtA[:size])
+}
+
+func (m *ResignResponse) MarshalToSizedBuffer(dAtA []byte) (int, error) {
+	i := len(dAtA)
+	_ = i
+	var l int
+	_ = l
+	if m.XXX_unrecognized != nil {
+		i -= len(m.XXX_unrecognized)
+		copy(dAtA[i:], m.XXX_unrecognized)
+	}
+	if m.Header != nil {
+		{
+			size, err := m.Header.MarshalToSizedBuffer(dAtA[:i])
+			if err != nil {
+				return 0, err
+			}
+			i -= size
+			i = encodeVarintV3Election(dAtA, i, uint64(size))
+		}
+		i--
+		dAtA[i] = 0xa
+	}
+	return len(dAtA) - i, nil
+}
+
+func (m *ProclaimRequest) Marshal() (dAtA []byte, err error) {
+	size := m.Size()
+	dAtA = make([]byte, size)
+	n, err := m.MarshalToSizedBuffer(dAtA[:size])
+	if err != nil {
+		return nil, err
+	}
+	return dAtA[:n], nil
+}
+
+func (m *ProclaimRequest) MarshalTo(dAtA []byte) (int, error) {
+	size := m.Size()
+	return m.MarshalToSizedBuffer(dAtA[:size])
+}
+
+func (m *ProclaimRequest) MarshalToSizedBuffer(dAtA []byte) (int, error) {
+	i := len(dAtA)
+	_ = i
+	var l int
+	_ = l
+	if m.XXX_unrecognized != nil {
+		i -= len(m.XXX_unrecognized)
+		copy(dAtA[i:], m.XXX_unrecognized)
+	}
+	if len(m.Value) > 0 {
+		i -= len(m.Value)
+		copy(dAtA[i:], m.Value)
+		i = encodeVarintV3Election(dAtA, i, uint64(len(m.Value)))
+		i--
+		dAtA[i] = 0x12
+	}
+	if m.Leader != nil {
+		{
+			size, err := m.Leader.MarshalToSizedBuffer(dAtA[:i])
+			if err != nil {
+				return 0, err
+			}
+			i -= size
+			i = encodeVarintV3Election(dAtA, i, uint64(size))
+		}
+		i--
+		dAtA[i] = 0xa
+	}
+	return len(dAtA) - i, nil
+}
+
+func (m *ProclaimResponse) Marshal() (dAtA []byte, err error) {
+	size := m.Size()
+	dAtA = make([]byte, size)
+	n, err := m.MarshalToSizedBuffer(dAtA[:size])
+	if err != nil {
+		return nil, err
+	}
+	return dAtA[:n], nil
+}
+
+func (m *ProclaimResponse) MarshalTo(dAtA []byte) (int, error) {
+	size := m.Size()
+	return m.MarshalToSizedBuffer(dAtA[:size])
+}
+
+func (m *ProclaimResponse) MarshalToSizedBuffer(dAtA []byte) (int, error) {
+	i := len(dAtA)
+	_ = i
+	var l int
+	_ = l
+	if m.XXX_unrecognized != nil {
+		i -= len(m.XXX_unrecognized)
+		copy(dAtA[i:], m.XXX_unrecognized)
+	}
+	if m.Header != nil {
+		{
+			size, err := m.Header.MarshalToSizedBuffer(dAtA[:i])
+			if err != nil {
+				return 0, err
+			}
+			i -= size
+			i = encodeVarintV3Election(dAtA, i, uint64(size))
+		}
+		i--
+		dAtA[i] = 0xa
+	}
+	return len(dAtA) - i, nil
+}
+
+func encodeVarintV3Election(dAtA []byte, offset int, v uint64) int {
+	offset -= sovV3Election(v)
+	base := offset
+	for v >= 1<<7 {
+		dAtA[offset] = uint8(v&0x7f | 0x80)
+		v >>= 7
+		offset++
+	}
+	dAtA[offset] = uint8(v)
+	return base
+}
+func (m *CampaignRequest) Size() (n int) {
+	if m == nil {
+		return 0
+	}
+	var l int
+	_ = l
+	l = len(m.Name)
+	if l > 0 {
+		n += 1 + l + sovV3Election(uint64(l))
+	}
+	if m.Lease != 0 {
+		n += 1 + sovV3Election(uint64(m.Lease))
+	}
+	l = len(m.Value)
+	if l > 0 {
+		n += 1 + l + sovV3Election(uint64(l))
+	}
+	if m.XXX_unrecognized != nil {
+		n += len(m.XXX_unrecognized)
+	}
+	return n
+}
+
+func (m *CampaignResponse) Size() (n int) {
+	if m == nil {
+		return 0
+	}
+	var l int
+	_ = l
+	if m.Header != nil {
+		l = m.Header.Size()
+		n += 1 + l + sovV3Election(uint64(l))
+	}
+	if m.Leader != nil {
+		l = m.Leader.Size()
+		n += 1 + l + sovV3Election(uint64(l))
+	}
+	if m.XXX_unrecognized != nil {
+		n += len(m.XXX_unrecognized)
+	}
+	return n
+}
+
+func (m *LeaderKey) Size() (n int) {
+	if m == nil {
+		return 0
+	}
+	var l int
+	_ = l
+	l = len(m.Name)
+	if l > 0 {
+		n += 1 + l + sovV3Election(uint64(l))
+	}
+	l = len(m.Key)
+	if l > 0 {
+		n += 1 + l + sovV3Election(uint64(l))
+	}
+	if m.Rev != 0 {
+		n += 1 + sovV3Election(uint64(m.Rev))
+	}
+	if m.Lease != 0 {
+		n += 1 + sovV3Election(uint64(m.Lease))
+	}
+	if m.XXX_unrecognized != nil {
+		n += len(m.XXX_unrecognized)
+	}
+	return n
+}
+
+func (m *LeaderRequest) Size() (n int) {
+	if m == nil {
+		return 0
+	}
+	var l int
+	_ = l
+	l = len(m.Name)
+	if l > 0 {
+		n += 1 + l + sovV3Election(uint64(l))
+	}
+	if m.XXX_unrecognized != nil {
+		n += len(m.XXX_unrecognized)
+	}
+	return n
+}
+
+func (m *LeaderResponse) Size() (n int) {
+	if m == nil {
+		return 0
+	}
+	var l int
+	_ = l
+	if m.Header != nil {
+		l = m.Header.Size()
+		n += 1 + l + sovV3Election(uint64(l))
+	}
+	if m.Kv != nil {
+		l = m.Kv.Size()
+		n += 1 + l + sovV3Election(uint64(l))
+	}
+	if m.XXX_unrecognized != nil {
+		n += len(m.XXX_unrecognized)
+	}
+	return n
+}
+
+func (m *ResignRequest) Size() (n int) {
+	if m == nil {
+		return 0
+	}
+	var l int
+	_ = l
+	if m.Leader != nil {
+		l = m.Leader.Size()
+		n += 1 + l + sovV3Election(uint64(l))
+	}
+	if m.XXX_unrecognized != nil {
+		n += len(m.XXX_unrecognized)
+	}
+	return n
+}
+
+func (m *ResignResponse) Size() (n int) {
+	if m == nil {
+		return 0
+	}
+	var l int
+	_ = l
+	if m.Header != nil {
+		l = m.Header.Size()
+		n += 1 + l + sovV3Election(uint64(l))
+	}
+	if m.XXX_unrecognized != nil {
+		n += len(m.XXX_unrecognized)
+	}
+	return n
+}
+
+func (m *ProclaimRequest) Size() (n int) {
+	if m == nil {
+		return 0
+	}
+	var l int
+	_ = l
+	if m.Leader != nil {
+		l = m.Leader.Size()
+		n += 1 + l + sovV3Election(uint64(l))
+	}
+	l = len(m.Value)
+	if l > 0 {
+		n += 1 + l + sovV3Election(uint64(l))
+	}
+	if m.XXX_unrecognized != nil {
+		n += len(m.XXX_unrecognized)
+	}
+	return n
+}
+
+func (m *ProclaimResponse) Size() (n int) {
+	if m == nil {
+		return 0
+	}
+	var l int
+	_ = l
+	if m.Header != nil {
+		l = m.Header.Size()
+		n += 1 + l + sovV3Election(uint64(l))
+	}
+	if m.XXX_unrecognized != nil {
+		n += len(m.XXX_unrecognized)
+	}
+	return n
+}
+
+func sovV3Election(x uint64) (n int) {
+	return (math_bits.Len64(x|1) + 6) / 7
+}
+func sozV3Election(x uint64) (n int) {
+	return sovV3Election(uint64((x << 1) ^ uint64((int64(x) >> 63))))
+}
+func (m *CampaignRequest) Unmarshal(dAtA []byte) error {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		preIndex := iNdEx
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return ErrIntOverflowV3Election
+			}
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= uint64(b&0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		if wireType == 4 {
+			return fmt.Errorf("proto: CampaignRequest: wiretype end group for non-group")
+		}
+		if fieldNum <= 0 {
+			return fmt.Errorf("proto: CampaignRequest: illegal tag %d (wire type %d)", fieldNum, wire)
+		}
+		switch fieldNum {
+		case 1:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Name", wireType)
+			}
+			var byteLen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowV3Election
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				byteLen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if byteLen < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			postIndex := iNdEx + byteLen
+			if postIndex < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.Name = append(m.Name[:0], dAtA[iNdEx:postIndex]...)
+			if m.Name == nil {
+				m.Name = []byte{}
+			}
+			iNdEx = postIndex
+		case 2:
+			if wireType != 0 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Lease", wireType)
+			}
+			m.Lease = 0
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowV3Election
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				m.Lease |= int64(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+		case 3:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Value", wireType)
+			}
+			var byteLen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowV3Election
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				byteLen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if byteLen < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			postIndex := iNdEx + byteLen
+			if postIndex < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.Value = append(m.Value[:0], dAtA[iNdEx:postIndex]...)
+			if m.Value == nil {
+				m.Value = []byte{}
+			}
+			iNdEx = postIndex
+		default:
+			iNdEx = preIndex
+			skippy, err := skipV3Election(dAtA[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.XXX_unrecognized = append(m.XXX_unrecognized, dAtA[iNdEx:iNdEx+skippy]...)
+			iNdEx += skippy
+		}
+	}
+
+	if iNdEx > l {
+		return io.ErrUnexpectedEOF
+	}
+	return nil
+}
+func (m *CampaignResponse) Unmarshal(dAtA []byte) error {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		preIndex := iNdEx
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return ErrIntOverflowV3Election
+			}
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= uint64(b&0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		if wireType == 4 {
+			return fmt.Errorf("proto: CampaignResponse: wiretype end group for non-group")
+		}
+		if fieldNum <= 0 {
+			return fmt.Errorf("proto: CampaignResponse: illegal tag %d (wire type %d)", fieldNum, wire)
+		}
+		switch fieldNum {
+		case 1:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Header", wireType)
+			}
+			var msglen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowV3Election
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				msglen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if msglen < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			postIndex := iNdEx + msglen
+			if postIndex < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			if m.Header == nil {
+				m.Header = &etcdserverpb.ResponseHeader{}
+			}
+			if err := m.Header.Unmarshal(dAtA[iNdEx:postIndex]); err != nil {
+				return err
+			}
+			iNdEx = postIndex
+		case 2:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Leader", wireType)
+			}
+			var msglen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowV3Election
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				msglen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if msglen < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			postIndex := iNdEx + msglen
+			if postIndex < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			if m.Leader == nil {
+				m.Leader = &LeaderKey{}
+			}
+			if err := m.Leader.Unmarshal(dAtA[iNdEx:postIndex]); err != nil {
+				return err
+			}
+			iNdEx = postIndex
+		default:
+			iNdEx = preIndex
+			skippy, err := skipV3Election(dAtA[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.XXX_unrecognized = append(m.XXX_unrecognized, dAtA[iNdEx:iNdEx+skippy]...)
+			iNdEx += skippy
+		}
+	}
+
+	if iNdEx > l {
+		return io.ErrUnexpectedEOF
+	}
+	return nil
+}
+func (m *LeaderKey) Unmarshal(dAtA []byte) error {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		preIndex := iNdEx
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return ErrIntOverflowV3Election
+			}
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= uint64(b&0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		if wireType == 4 {
+			return fmt.Errorf("proto: LeaderKey: wiretype end group for non-group")
+		}
+		if fieldNum <= 0 {
+			return fmt.Errorf("proto: LeaderKey: illegal tag %d (wire type %d)", fieldNum, wire)
+		}
+		switch fieldNum {
+		case 1:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Name", wireType)
+			}
+			var byteLen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowV3Election
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				byteLen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if byteLen < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			postIndex := iNdEx + byteLen
+			if postIndex < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.Name = append(m.Name[:0], dAtA[iNdEx:postIndex]...)
+			if m.Name == nil {
+				m.Name = []byte{}
+			}
+			iNdEx = postIndex
+		case 2:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Key", wireType)
+			}
+			var byteLen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowV3Election
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				byteLen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if byteLen < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			postIndex := iNdEx + byteLen
+			if postIndex < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.Key = append(m.Key[:0], dAtA[iNdEx:postIndex]...)
+			if m.Key == nil {
+				m.Key = []byte{}
+			}
+			iNdEx = postIndex
+		case 3:
+			if wireType != 0 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Rev", wireType)
+			}
+			m.Rev = 0
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowV3Election
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				m.Rev |= int64(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+		case 4:
+			if wireType != 0 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Lease", wireType)
+			}
+			m.Lease = 0
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowV3Election
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				m.Lease |= int64(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+		default:
+			iNdEx = preIndex
+			skippy, err := skipV3Election(dAtA[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.XXX_unrecognized = append(m.XXX_unrecognized, dAtA[iNdEx:iNdEx+skippy]...)
+			iNdEx += skippy
+		}
+	}
+
+	if iNdEx > l {
+		return io.ErrUnexpectedEOF
+	}
+	return nil
+}
+func (m *LeaderRequest) Unmarshal(dAtA []byte) error {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		preIndex := iNdEx
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return ErrIntOverflowV3Election
+			}
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= uint64(b&0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		if wireType == 4 {
+			return fmt.Errorf("proto: LeaderRequest: wiretype end group for non-group")
+		}
+		if fieldNum <= 0 {
+			return fmt.Errorf("proto: LeaderRequest: illegal tag %d (wire type %d)", fieldNum, wire)
+		}
+		switch fieldNum {
+		case 1:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Name", wireType)
+			}
+			var byteLen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowV3Election
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				byteLen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if byteLen < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			postIndex := iNdEx + byteLen
+			if postIndex < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.Name = append(m.Name[:0], dAtA[iNdEx:postIndex]...)
+			if m.Name == nil {
+				m.Name = []byte{}
+			}
+			iNdEx = postIndex
+		default:
+			iNdEx = preIndex
+			skippy, err := skipV3Election(dAtA[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.XXX_unrecognized = append(m.XXX_unrecognized, dAtA[iNdEx:iNdEx+skippy]...)
+			iNdEx += skippy
+		}
+	}
+
+	if iNdEx > l {
+		return io.ErrUnexpectedEOF
+	}
+	return nil
+}
+func (m *LeaderResponse) Unmarshal(dAtA []byte) error {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		preIndex := iNdEx
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return ErrIntOverflowV3Election
+			}
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= uint64(b&0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		if wireType == 4 {
+			return fmt.Errorf("proto: LeaderResponse: wiretype end group for non-group")
+		}
+		if fieldNum <= 0 {
+			return fmt.Errorf("proto: LeaderResponse: illegal tag %d (wire type %d)", fieldNum, wire)
+		}
+		switch fieldNum {
+		case 1:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Header", wireType)
+			}
+			var msglen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowV3Election
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				msglen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if msglen < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			postIndex := iNdEx + msglen
+			if postIndex < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			if m.Header == nil {
+				m.Header = &etcdserverpb.ResponseHeader{}
+			}
+			if err := m.Header.Unmarshal(dAtA[iNdEx:postIndex]); err != nil {
+				return err
+			}
+			iNdEx = postIndex
+		case 2:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Kv", wireType)
+			}
+			var msglen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowV3Election
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				msglen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if msglen < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			postIndex := iNdEx + msglen
+			if postIndex < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			if m.Kv == nil {
+				m.Kv = &mvccpb.KeyValue{}
+			}
+			if err := m.Kv.Unmarshal(dAtA[iNdEx:postIndex]); err != nil {
+				return err
+			}
+			iNdEx = postIndex
+		default:
+			iNdEx = preIndex
+			skippy, err := skipV3Election(dAtA[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.XXX_unrecognized = append(m.XXX_unrecognized, dAtA[iNdEx:iNdEx+skippy]...)
+			iNdEx += skippy
+		}
+	}
+
+	if iNdEx > l {
+		return io.ErrUnexpectedEOF
+	}
+	return nil
+}
+func (m *ResignRequest) Unmarshal(dAtA []byte) error {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		preIndex := iNdEx
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return ErrIntOverflowV3Election
+			}
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= uint64(b&0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		if wireType == 4 {
+			return fmt.Errorf("proto: ResignRequest: wiretype end group for non-group")
+		}
+		if fieldNum <= 0 {
+			return fmt.Errorf("proto: ResignRequest: illegal tag %d (wire type %d)", fieldNum, wire)
+		}
+		switch fieldNum {
+		case 1:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Leader", wireType)
+			}
+			var msglen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowV3Election
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				msglen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if msglen < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			postIndex := iNdEx + msglen
+			if postIndex < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			if m.Leader == nil {
+				m.Leader = &LeaderKey{}
+			}
+			if err := m.Leader.Unmarshal(dAtA[iNdEx:postIndex]); err != nil {
+				return err
+			}
+			iNdEx = postIndex
+		default:
+			iNdEx = preIndex
+			skippy, err := skipV3Election(dAtA[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.XXX_unrecognized = append(m.XXX_unrecognized, dAtA[iNdEx:iNdEx+skippy]...)
+			iNdEx += skippy
+		}
+	}
+
+	if iNdEx > l {
+		return io.ErrUnexpectedEOF
+	}
+	return nil
+}
+func (m *ResignResponse) Unmarshal(dAtA []byte) error {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		preIndex := iNdEx
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return ErrIntOverflowV3Election
+			}
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= uint64(b&0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		if wireType == 4 {
+			return fmt.Errorf("proto: ResignResponse: wiretype end group for non-group")
+		}
+		if fieldNum <= 0 {
+			return fmt.Errorf("proto: ResignResponse: illegal tag %d (wire type %d)", fieldNum, wire)
+		}
+		switch fieldNum {
+		case 1:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Header", wireType)
+			}
+			var msglen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowV3Election
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				msglen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if msglen < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			postIndex := iNdEx + msglen
+			if postIndex < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			if m.Header == nil {
+				m.Header = &etcdserverpb.ResponseHeader{}
+			}
+			if err := m.Header.Unmarshal(dAtA[iNdEx:postIndex]); err != nil {
+				return err
+			}
+			iNdEx = postIndex
+		default:
+			iNdEx = preIndex
+			skippy, err := skipV3Election(dAtA[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.XXX_unrecognized = append(m.XXX_unrecognized, dAtA[iNdEx:iNdEx+skippy]...)
+			iNdEx += skippy
+		}
+	}
+
+	if iNdEx > l {
+		return io.ErrUnexpectedEOF
+	}
+	return nil
+}
+func (m *ProclaimRequest) Unmarshal(dAtA []byte) error {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		preIndex := iNdEx
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return ErrIntOverflowV3Election
+			}
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= uint64(b&0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		if wireType == 4 {
+			return fmt.Errorf("proto: ProclaimRequest: wiretype end group for non-group")
+		}
+		if fieldNum <= 0 {
+			return fmt.Errorf("proto: ProclaimRequest: illegal tag %d (wire type %d)", fieldNum, wire)
+		}
+		switch fieldNum {
+		case 1:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Leader", wireType)
+			}
+			var msglen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowV3Election
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				msglen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if msglen < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			postIndex := iNdEx + msglen
+			if postIndex < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			if m.Leader == nil {
+				m.Leader = &LeaderKey{}
+			}
+			if err := m.Leader.Unmarshal(dAtA[iNdEx:postIndex]); err != nil {
+				return err
+			}
+			iNdEx = postIndex
+		case 2:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Value", wireType)
+			}
+			var byteLen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowV3Election
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				byteLen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if byteLen < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			postIndex := iNdEx + byteLen
+			if postIndex < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.Value = append(m.Value[:0], dAtA[iNdEx:postIndex]...)
+			if m.Value == nil {
+				m.Value = []byte{}
+			}
+			iNdEx = postIndex
+		default:
+			iNdEx = preIndex
+			skippy, err := skipV3Election(dAtA[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.XXX_unrecognized = append(m.XXX_unrecognized, dAtA[iNdEx:iNdEx+skippy]...)
+			iNdEx += skippy
+		}
+	}
+
+	if iNdEx > l {
+		return io.ErrUnexpectedEOF
+	}
+	return nil
+}
+func (m *ProclaimResponse) Unmarshal(dAtA []byte) error {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		preIndex := iNdEx
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return ErrIntOverflowV3Election
+			}
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= uint64(b&0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		if wireType == 4 {
+			return fmt.Errorf("proto: ProclaimResponse: wiretype end group for non-group")
+		}
+		if fieldNum <= 0 {
+			return fmt.Errorf("proto: ProclaimResponse: illegal tag %d (wire type %d)", fieldNum, wire)
+		}
+		switch fieldNum {
+		case 1:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Header", wireType)
+			}
+			var msglen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowV3Election
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				msglen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if msglen < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			postIndex := iNdEx + msglen
+			if postIndex < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			if m.Header == nil {
+				m.Header = &etcdserverpb.ResponseHeader{}
+			}
+			if err := m.Header.Unmarshal(dAtA[iNdEx:postIndex]); err != nil {
+				return err
+			}
+			iNdEx = postIndex
+		default:
+			iNdEx = preIndex
+			skippy, err := skipV3Election(dAtA[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
+				return ErrInvalidLengthV3Election
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.XXX_unrecognized = append(m.XXX_unrecognized, dAtA[iNdEx:iNdEx+skippy]...)
+			iNdEx += skippy
+		}
+	}
+
+	if iNdEx > l {
+		return io.ErrUnexpectedEOF
+	}
+	return nil
+}
+func skipV3Election(dAtA []byte) (n int, err error) {
+	l := len(dAtA)
+	iNdEx := 0
+	depth := 0
+	for iNdEx < l {
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return 0, ErrIntOverflowV3Election
+			}
+			if iNdEx >= l {
+				return 0, io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= (uint64(b) & 0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		wireType := int(wire & 0x7)
+		switch wireType {
+		case 0:
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return 0, ErrIntOverflowV3Election
+				}
+				if iNdEx >= l {
+					return 0, io.ErrUnexpectedEOF
+				}
+				iNdEx++
+				if dAtA[iNdEx-1] < 0x80 {
+					break
+				}
+			}
+		case 1:
+			iNdEx += 8
+		case 2:
+			var length int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return 0, ErrIntOverflowV3Election
+				}
+				if iNdEx >= l {
+					return 0, io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				length |= (int(b) & 0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if length < 0 {
+				return 0, ErrInvalidLengthV3Election
+			}
+			iNdEx += length
+		case 3:
+			depth++
+		case 4:
+			if depth == 0 {
+				return 0, ErrUnexpectedEndOfGroupV3Election
+			}
+			depth--
+		case 5:
+			iNdEx += 4
+		default:
+			return 0, fmt.Errorf("proto: illegal wireType %d", wireType)
+		}
+		if iNdEx < 0 {
+			return 0, ErrInvalidLengthV3Election
+		}
+		if depth == 0 {
+			return iNdEx, nil
+		}
+	}
+	return 0, io.ErrUnexpectedEOF
+}
+
+var (
+	ErrInvalidLengthV3Election        = fmt.Errorf("proto: negative length found during unmarshaling")
+	ErrIntOverflowV3Election          = fmt.Errorf("proto: integer overflow")
+	ErrUnexpectedEndOfGroupV3Election = fmt.Errorf("proto: unexpected end of group")
+)
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3election/v3electionpb/v3election.proto b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3election/v3electionpb/v3election.proto
new file mode 100644
index 0000000..6042776
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3election/v3electionpb/v3election.proto
@@ -0,0 +1,121 @@
+syntax = "proto3";
+package v3electionpb;
+
+import "gogoproto/gogo.proto";
+import "etcd/api/etcdserverpb/rpc.proto";
+import "etcd/api/mvccpb/kv.proto";
+
+// for grpc-gateway
+import "google/api/annotations.proto";
+
+option go_package = "go.etcd.io/etcd/server/v3/etcdserver/api/v3election/v3electionpb";
+
+option (gogoproto.marshaler_all) = true;
+option (gogoproto.unmarshaler_all) = true;
+
+// The election service exposes client-side election facilities as a gRPC interface.
+service Election {
+  // Campaign waits to acquire leadership in an election, returning a LeaderKey
+  // representing the leadership if successful. The LeaderKey can then be used
+  // to issue new values on the election, transactionally guard API requests on
+  // leadership still being held, and resign from the election.
+  rpc Campaign(CampaignRequest) returns (CampaignResponse) {
+      option (google.api.http) = {
+        post: "/v3/election/campaign"
+        body: "*"
+    };
+  }
+  // Proclaim updates the leader's posted value with a new value.
+  rpc Proclaim(ProclaimRequest) returns (ProclaimResponse) {
+      option (google.api.http) = {
+        post: "/v3/election/proclaim"
+        body: "*"
+    };
+  }
+  // Leader returns the current election proclamation, if any.
+  rpc Leader(LeaderRequest) returns (LeaderResponse) {
+      option (google.api.http) = {
+        post: "/v3/election/leader"
+        body: "*"
+    };
+  }
+  // Observe streams election proclamations in-order as made by the election's
+  // elected leaders.
+  rpc Observe(LeaderRequest) returns (stream LeaderResponse) {
+      option (google.api.http) = {
+        post: "/v3/election/observe"
+        body: "*"
+    };
+  }
+  // Resign releases election leadership so other campaigners may acquire
+  // leadership on the election.
+  rpc Resign(ResignRequest) returns (ResignResponse) {
+      option (google.api.http) = {
+        post: "/v3/election/resign"
+        body: "*"
+    };
+  }
+}
+
+message CampaignRequest {
+  // name is the election's identifier for the campaign.
+  bytes name = 1;
+  // lease is the ID of the lease attached to leadership of the election. If the
+  // lease expires or is revoked before resigning leadership, then the
+  // leadership is transferred to the next campaigner, if any.
+  int64 lease = 2;
+  // value is the initial proclaimed value set when the campaigner wins the
+  // election.
+  bytes value = 3;
+}
+
+message CampaignResponse {
+  etcdserverpb.ResponseHeader header = 1;
+  // leader describes the resources used for holding leadereship of the election.
+  LeaderKey leader = 2;
+}
+
+message LeaderKey {
+  // name is the election identifier that corresponds to the leadership key.
+  bytes name = 1;
+  // key is an opaque key representing the ownership of the election. If the key
+  // is deleted, then leadership is lost.
+  bytes key = 2;
+  // rev is the creation revision of the key. It can be used to test for ownership
+  // of an election during transactions by testing the key's creation revision
+  // matches rev.
+  int64 rev = 3;
+  // lease is the lease ID of the election leader.
+  int64 lease = 4;
+}
+
+message LeaderRequest {
+  // name is the election identifier for the leadership information.
+  bytes name = 1;
+}
+
+message LeaderResponse {
+  etcdserverpb.ResponseHeader header = 1;
+  // kv is the key-value pair representing the latest leader update.
+  mvccpb.KeyValue kv = 2;
+}
+
+message ResignRequest {
+  // leader is the leadership to relinquish by resignation.
+  LeaderKey leader = 1;
+}
+
+message ResignResponse {
+  etcdserverpb.ResponseHeader header = 1;
+}
+
+message ProclaimRequest {
+  // leader is the leadership hold on the election.
+  LeaderKey leader = 1;
+  // value is an update meant to overwrite the leader's current value.
+  bytes value = 2;
+}
+
+message ProclaimResponse {
+  etcdserverpb.ResponseHeader header = 1;
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3lock/doc.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3lock/doc.go
new file mode 100644
index 0000000..e0a1008
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3lock/doc.go
@@ -0,0 +1,16 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package v3lock provides a v3 locking service from an etcdserver.
+package v3lock
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3lock/lock.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3lock/lock.go
new file mode 100644
index 0000000..c8ef56e
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3lock/lock.go
@@ -0,0 +1,56 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v3lock
+
+import (
+	"context"
+
+	clientv3 "go.etcd.io/etcd/client/v3"
+	"go.etcd.io/etcd/client/v3/concurrency"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v3lock/v3lockpb"
+)
+
+type lockServer struct {
+	c *clientv3.Client
+}
+
+func NewLockServer(c *clientv3.Client) v3lockpb.LockServer {
+	return &lockServer{c}
+}
+
+func (ls *lockServer) Lock(ctx context.Context, req *v3lockpb.LockRequest) (*v3lockpb.LockResponse, error) {
+	s, err := concurrency.NewSession(
+		ls.c,
+		concurrency.WithLease(clientv3.LeaseID(req.Lease)),
+		concurrency.WithContext(ctx),
+	)
+	if err != nil {
+		return nil, err
+	}
+	s.Orphan()
+	m := concurrency.NewMutex(s, string(req.Name))
+	if err = m.Lock(ctx); err != nil {
+		return nil, err
+	}
+	return &v3lockpb.LockResponse{Header: m.Header(), Key: []byte(m.Key())}, nil
+}
+
+func (ls *lockServer) Unlock(ctx context.Context, req *v3lockpb.UnlockRequest) (*v3lockpb.UnlockResponse, error) {
+	resp, err := ls.c.Delete(ctx, string(req.Key))
+	if err != nil {
+		return nil, err
+	}
+	return &v3lockpb.UnlockResponse{Header: resp.Header}, nil
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3lock/v3lockpb/gw/v3lock.pb.gw.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3lock/v3lockpb/gw/v3lock.pb.gw.go
new file mode 100644
index 0000000..5efb759
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3lock/v3lockpb/gw/v3lock.pb.gw.go
@@ -0,0 +1,220 @@
+// Code generated by protoc-gen-grpc-gateway. DO NOT EDIT.
+// source: server/etcdserver/api/v3lock/v3lockpb/v3lock.proto
+
+/*
+Package v3lockpb is a reverse proxy.
+
+It translates gRPC into RESTful JSON APIs.
+*/
+package gw
+
+import (
+	protov1 "github.com/golang/protobuf/proto"
+
+	"context"
+	"errors"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v3lock/v3lockpb"
+	"io"
+	"net/http"
+
+	"github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
+	"github.com/grpc-ecosystem/grpc-gateway/v2/utilities"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/grpclog"
+	"google.golang.org/grpc/metadata"
+	"google.golang.org/grpc/status"
+	"google.golang.org/protobuf/proto"
+)
+
+// Suppress "imported and not used" errors
+var (
+	_ codes.Code
+	_ io.Reader
+	_ status.Status
+	_ = errors.New
+	_ = runtime.String
+	_ = utilities.NewDoubleArray
+	_ = metadata.Join
+)
+
+func request_Lock_Lock_0(ctx context.Context, marshaler runtime.Marshaler, client v3lockpb.LockClient, req *http.Request, pathParams map[string]string) (proto.Message, runtime.ServerMetadata, error) {
+	var (
+		protoReq v3lockpb.LockRequest
+		metadata runtime.ServerMetadata
+	)
+	if err := marshaler.NewDecoder(req.Body).Decode(protov1.MessageV2(&protoReq)); err != nil && !errors.Is(err, io.EOF) {
+		return nil, metadata, status.Errorf(codes.InvalidArgument, "%v", err)
+	}
+	msg, err := client.Lock(ctx, &protoReq, grpc.Header(&metadata.HeaderMD), grpc.Trailer(&metadata.TrailerMD))
+	return protov1.MessageV2(msg), metadata, err
+}
+
+func local_request_Lock_Lock_0(ctx context.Context, marshaler runtime.Marshaler, server v3lockpb.LockServer, req *http.Request, pathParams map[string]string) (proto.Message, runtime.ServerMetadata, error) {
+	var (
+		protoReq v3lockpb.LockRequest
+		metadata runtime.ServerMetadata
+	)
+	if err := marshaler.NewDecoder(req.Body).Decode(protov1.MessageV2(&protoReq)); err != nil && !errors.Is(err, io.EOF) {
+		return nil, metadata, status.Errorf(codes.InvalidArgument, "%v", err)
+	}
+	msg, err := server.Lock(ctx, &protoReq)
+	return protov1.MessageV2(msg), metadata, err
+}
+
+func request_Lock_Unlock_0(ctx context.Context, marshaler runtime.Marshaler, client v3lockpb.LockClient, req *http.Request, pathParams map[string]string) (proto.Message, runtime.ServerMetadata, error) {
+	var (
+		protoReq v3lockpb.UnlockRequest
+		metadata runtime.ServerMetadata
+	)
+	if err := marshaler.NewDecoder(req.Body).Decode(protov1.MessageV2(&protoReq)); err != nil && !errors.Is(err, io.EOF) {
+		return nil, metadata, status.Errorf(codes.InvalidArgument, "%v", err)
+	}
+	msg, err := client.Unlock(ctx, &protoReq, grpc.Header(&metadata.HeaderMD), grpc.Trailer(&metadata.TrailerMD))
+	return protov1.MessageV2(msg), metadata, err
+}
+
+func local_request_Lock_Unlock_0(ctx context.Context, marshaler runtime.Marshaler, server v3lockpb.LockServer, req *http.Request, pathParams map[string]string) (proto.Message, runtime.ServerMetadata, error) {
+	var (
+		protoReq v3lockpb.UnlockRequest
+		metadata runtime.ServerMetadata
+	)
+	if err := marshaler.NewDecoder(req.Body).Decode(protov1.MessageV2(&protoReq)); err != nil && !errors.Is(err, io.EOF) {
+		return nil, metadata, status.Errorf(codes.InvalidArgument, "%v", err)
+	}
+	msg, err := server.Unlock(ctx, &protoReq)
+	return protov1.MessageV2(msg), metadata, err
+}
+
+// v3lockpb.RegisterLockHandlerServer registers the http handlers for service Lock to "mux".
+// UnaryRPC     :call v3lockpb.LockServer directly.
+// StreamingRPC :currently unsupported pending https://github.com/grpc/grpc-go/issues/906.
+// Note that using this registration option will cause many gRPC library features to stop working. Consider using RegisterLockHandlerFromEndpoint instead.
+// GRPC interceptors will not work for this type of registration. To use interceptors, you must use the "runtime.WithMiddlewares" option in the "runtime.NewServeMux" call.
+func RegisterLockHandlerServer(ctx context.Context, mux *runtime.ServeMux, server v3lockpb.LockServer) error {
+	mux.Handle(http.MethodPost, pattern_Lock_Lock_0, func(w http.ResponseWriter, req *http.Request, pathParams map[string]string) {
+		ctx, cancel := context.WithCancel(req.Context())
+		defer cancel()
+		var stream runtime.ServerTransportStream
+		ctx = grpc.NewContextWithServerTransportStream(ctx, &stream)
+		inboundMarshaler, outboundMarshaler := runtime.MarshalerForRequest(mux, req)
+		annotatedContext, err := runtime.AnnotateIncomingContext(ctx, mux, req, "/v3lockpb.Lock/Lock", runtime.WithHTTPPathPattern("/v3/lock/lock"))
+		if err != nil {
+			runtime.HTTPError(ctx, mux, outboundMarshaler, w, req, err)
+			return
+		}
+		resp, md, err := local_request_Lock_Lock_0(annotatedContext, inboundMarshaler, server, req, pathParams)
+		md.HeaderMD, md.TrailerMD = metadata.Join(md.HeaderMD, stream.Header()), metadata.Join(md.TrailerMD, stream.Trailer())
+		annotatedContext = runtime.NewServerMetadataContext(annotatedContext, md)
+		if err != nil {
+			runtime.HTTPError(annotatedContext, mux, outboundMarshaler, w, req, err)
+			return
+		}
+		forward_Lock_Lock_0(annotatedContext, mux, outboundMarshaler, w, req, resp, mux.GetForwardResponseOptions()...)
+	})
+	mux.Handle(http.MethodPost, pattern_Lock_Unlock_0, func(w http.ResponseWriter, req *http.Request, pathParams map[string]string) {
+		ctx, cancel := context.WithCancel(req.Context())
+		defer cancel()
+		var stream runtime.ServerTransportStream
+		ctx = grpc.NewContextWithServerTransportStream(ctx, &stream)
+		inboundMarshaler, outboundMarshaler := runtime.MarshalerForRequest(mux, req)
+		annotatedContext, err := runtime.AnnotateIncomingContext(ctx, mux, req, "/v3lockpb.Lock/Unlock", runtime.WithHTTPPathPattern("/v3/lock/unlock"))
+		if err != nil {
+			runtime.HTTPError(ctx, mux, outboundMarshaler, w, req, err)
+			return
+		}
+		resp, md, err := local_request_Lock_Unlock_0(annotatedContext, inboundMarshaler, server, req, pathParams)
+		md.HeaderMD, md.TrailerMD = metadata.Join(md.HeaderMD, stream.Header()), metadata.Join(md.TrailerMD, stream.Trailer())
+		annotatedContext = runtime.NewServerMetadataContext(annotatedContext, md)
+		if err != nil {
+			runtime.HTTPError(annotatedContext, mux, outboundMarshaler, w, req, err)
+			return
+		}
+		forward_Lock_Unlock_0(annotatedContext, mux, outboundMarshaler, w, req, resp, mux.GetForwardResponseOptions()...)
+	})
+
+	return nil
+}
+
+// RegisterLockHandlerFromEndpoint is same as RegisterLockHandler but
+// automatically dials to "endpoint" and closes the connection when "ctx" gets done.
+func RegisterLockHandlerFromEndpoint(ctx context.Context, mux *runtime.ServeMux, endpoint string, opts []grpc.DialOption) (err error) {
+	conn, err := grpc.NewClient(endpoint, opts...)
+	if err != nil {
+		return err
+	}
+	defer func() {
+		if err != nil {
+			if cerr := conn.Close(); cerr != nil {
+				grpclog.Errorf("Failed to close conn to %s: %v", endpoint, cerr)
+			}
+			return
+		}
+		go func() {
+			<-ctx.Done()
+			if cerr := conn.Close(); cerr != nil {
+				grpclog.Errorf("Failed to close conn to %s: %v", endpoint, cerr)
+			}
+		}()
+	}()
+	return RegisterLockHandler(ctx, mux, conn)
+}
+
+// RegisterLockHandler registers the http handlers for service Lock to "mux".
+// The handlers forward requests to the grpc endpoint over "conn".
+func RegisterLockHandler(ctx context.Context, mux *runtime.ServeMux, conn *grpc.ClientConn) error {
+	return RegisterLockHandlerClient(ctx, mux, v3lockpb.NewLockClient(conn))
+}
+
+// v3lockpb.RegisterLockHandlerClient registers the http handlers for service Lock
+// to "mux". The handlers forward requests to the grpc endpoint over the given implementation of "LockClient".
+// Note: the gRPC framework executes interceptors within the gRPC handler. If the passed in "LockClient"
+// doesn't go through the normal gRPC flow (creating a gRPC client etc.) then it will be up to the passed in
+// "LockClient" to call the correct interceptors. This client ignores the HTTP middlewares.
+func RegisterLockHandlerClient(ctx context.Context, mux *runtime.ServeMux, client v3lockpb.LockClient) error {
+	mux.Handle(http.MethodPost, pattern_Lock_Lock_0, func(w http.ResponseWriter, req *http.Request, pathParams map[string]string) {
+		ctx, cancel := context.WithCancel(req.Context())
+		defer cancel()
+		inboundMarshaler, outboundMarshaler := runtime.MarshalerForRequest(mux, req)
+		annotatedContext, err := runtime.AnnotateContext(ctx, mux, req, "/v3lockpb.Lock/Lock", runtime.WithHTTPPathPattern("/v3/lock/lock"))
+		if err != nil {
+			runtime.HTTPError(ctx, mux, outboundMarshaler, w, req, err)
+			return
+		}
+		resp, md, err := request_Lock_Lock_0(annotatedContext, inboundMarshaler, client, req, pathParams)
+		annotatedContext = runtime.NewServerMetadataContext(annotatedContext, md)
+		if err != nil {
+			runtime.HTTPError(annotatedContext, mux, outboundMarshaler, w, req, err)
+			return
+		}
+		forward_Lock_Lock_0(annotatedContext, mux, outboundMarshaler, w, req, resp, mux.GetForwardResponseOptions()...)
+	})
+	mux.Handle(http.MethodPost, pattern_Lock_Unlock_0, func(w http.ResponseWriter, req *http.Request, pathParams map[string]string) {
+		ctx, cancel := context.WithCancel(req.Context())
+		defer cancel()
+		inboundMarshaler, outboundMarshaler := runtime.MarshalerForRequest(mux, req)
+		annotatedContext, err := runtime.AnnotateContext(ctx, mux, req, "/v3lockpb.Lock/Unlock", runtime.WithHTTPPathPattern("/v3/lock/unlock"))
+		if err != nil {
+			runtime.HTTPError(ctx, mux, outboundMarshaler, w, req, err)
+			return
+		}
+		resp, md, err := request_Lock_Unlock_0(annotatedContext, inboundMarshaler, client, req, pathParams)
+		annotatedContext = runtime.NewServerMetadataContext(annotatedContext, md)
+		if err != nil {
+			runtime.HTTPError(annotatedContext, mux, outboundMarshaler, w, req, err)
+			return
+		}
+		forward_Lock_Unlock_0(annotatedContext, mux, outboundMarshaler, w, req, resp, mux.GetForwardResponseOptions()...)
+	})
+	return nil
+}
+
+var (
+	pattern_Lock_Lock_0   = runtime.MustPattern(runtime.NewPattern(1, []int{2, 0, 2, 1, 2, 1}, []string{"v3", "lock"}, ""))
+	pattern_Lock_Unlock_0 = runtime.MustPattern(runtime.NewPattern(1, []int{2, 0, 2, 1, 2, 2}, []string{"v3", "lock", "unlock"}, ""))
+)
+
+var (
+	forward_Lock_Lock_0   = runtime.ForwardResponseMessage
+	forward_Lock_Unlock_0 = runtime.ForwardResponseMessage
+)
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3lock/v3lockpb/v3lock.pb.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3lock/v3lockpb/v3lock.pb.go
new file mode 100644
index 0000000..39c04ab
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3lock/v3lockpb/v3lock.pb.go
@@ -0,0 +1,1143 @@
+// Code generated by protoc-gen-gogo. DO NOT EDIT.
+// source: v3lock.proto
+
+package v3lockpb
+
+import (
+	context "context"
+	fmt "fmt"
+	io "io"
+	math "math"
+	math_bits "math/bits"
+
+	_ "github.com/gogo/protobuf/gogoproto"
+	proto "github.com/golang/protobuf/proto"
+	etcdserverpb "go.etcd.io/etcd/api/v3/etcdserverpb"
+	_ "google.golang.org/genproto/googleapis/api/annotations"
+	grpc "google.golang.org/grpc"
+	codes "google.golang.org/grpc/codes"
+	status "google.golang.org/grpc/status"
+)
+
+// Reference imports to suppress errors if they are not otherwise used.
+var _ = proto.Marshal
+var _ = fmt.Errorf
+var _ = math.Inf
+
+// This is a compile-time assertion to ensure that this generated file
+// is compatible with the proto package it is being compiled against.
+// A compilation error at this line likely means your copy of the
+// proto package needs to be updated.
+const _ = proto.ProtoPackageIsVersion3 // please upgrade the proto package
+
+type LockRequest struct {
+	// name is the identifier for the distributed shared lock to be acquired.
+	Name []byte `protobuf:"bytes,1,opt,name=name,proto3" json:"name,omitempty"`
+	// lease is the ID of the lease that will be attached to ownership of the
+	// lock. If the lease expires or is revoked and currently holds the lock,
+	// the lock is automatically released. Calls to Lock with the same lease will
+	// be treated as a single acquisition; locking twice with the same lease is a
+	// no-op.
+	Lease                int64    `protobuf:"varint,2,opt,name=lease,proto3" json:"lease,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
+}
+
+func (m *LockRequest) Reset()         { *m = LockRequest{} }
+func (m *LockRequest) String() string { return proto.CompactTextString(m) }
+func (*LockRequest) ProtoMessage()    {}
+func (*LockRequest) Descriptor() ([]byte, []int) {
+	return fileDescriptor_52389b3e2f253201, []int{0}
+}
+func (m *LockRequest) XXX_Unmarshal(b []byte) error {
+	return m.Unmarshal(b)
+}
+func (m *LockRequest) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	if deterministic {
+		return xxx_messageInfo_LockRequest.Marshal(b, m, deterministic)
+	} else {
+		b = b[:cap(b)]
+		n, err := m.MarshalToSizedBuffer(b)
+		if err != nil {
+			return nil, err
+		}
+		return b[:n], nil
+	}
+}
+func (m *LockRequest) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_LockRequest.Merge(m, src)
+}
+func (m *LockRequest) XXX_Size() int {
+	return m.Size()
+}
+func (m *LockRequest) XXX_DiscardUnknown() {
+	xxx_messageInfo_LockRequest.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_LockRequest proto.InternalMessageInfo
+
+func (m *LockRequest) GetName() []byte {
+	if m != nil {
+		return m.Name
+	}
+	return nil
+}
+
+func (m *LockRequest) GetLease() int64 {
+	if m != nil {
+		return m.Lease
+	}
+	return 0
+}
+
+type LockResponse struct {
+	Header *etcdserverpb.ResponseHeader `protobuf:"bytes,1,opt,name=header,proto3" json:"header,omitempty"`
+	// key is a key that will exist on etcd for the duration that the Lock caller
+	// owns the lock. Users should not modify this key or the lock may exhibit
+	// undefined behavior.
+	Key                  []byte   `protobuf:"bytes,2,opt,name=key,proto3" json:"key,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
+}
+
+func (m *LockResponse) Reset()         { *m = LockResponse{} }
+func (m *LockResponse) String() string { return proto.CompactTextString(m) }
+func (*LockResponse) ProtoMessage()    {}
+func (*LockResponse) Descriptor() ([]byte, []int) {
+	return fileDescriptor_52389b3e2f253201, []int{1}
+}
+func (m *LockResponse) XXX_Unmarshal(b []byte) error {
+	return m.Unmarshal(b)
+}
+func (m *LockResponse) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	if deterministic {
+		return xxx_messageInfo_LockResponse.Marshal(b, m, deterministic)
+	} else {
+		b = b[:cap(b)]
+		n, err := m.MarshalToSizedBuffer(b)
+		if err != nil {
+			return nil, err
+		}
+		return b[:n], nil
+	}
+}
+func (m *LockResponse) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_LockResponse.Merge(m, src)
+}
+func (m *LockResponse) XXX_Size() int {
+	return m.Size()
+}
+func (m *LockResponse) XXX_DiscardUnknown() {
+	xxx_messageInfo_LockResponse.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_LockResponse proto.InternalMessageInfo
+
+func (m *LockResponse) GetHeader() *etcdserverpb.ResponseHeader {
+	if m != nil {
+		return m.Header
+	}
+	return nil
+}
+
+func (m *LockResponse) GetKey() []byte {
+	if m != nil {
+		return m.Key
+	}
+	return nil
+}
+
+type UnlockRequest struct {
+	// key is the lock ownership key granted by Lock.
+	Key                  []byte   `protobuf:"bytes,1,opt,name=key,proto3" json:"key,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
+}
+
+func (m *UnlockRequest) Reset()         { *m = UnlockRequest{} }
+func (m *UnlockRequest) String() string { return proto.CompactTextString(m) }
+func (*UnlockRequest) ProtoMessage()    {}
+func (*UnlockRequest) Descriptor() ([]byte, []int) {
+	return fileDescriptor_52389b3e2f253201, []int{2}
+}
+func (m *UnlockRequest) XXX_Unmarshal(b []byte) error {
+	return m.Unmarshal(b)
+}
+func (m *UnlockRequest) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	if deterministic {
+		return xxx_messageInfo_UnlockRequest.Marshal(b, m, deterministic)
+	} else {
+		b = b[:cap(b)]
+		n, err := m.MarshalToSizedBuffer(b)
+		if err != nil {
+			return nil, err
+		}
+		return b[:n], nil
+	}
+}
+func (m *UnlockRequest) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_UnlockRequest.Merge(m, src)
+}
+func (m *UnlockRequest) XXX_Size() int {
+	return m.Size()
+}
+func (m *UnlockRequest) XXX_DiscardUnknown() {
+	xxx_messageInfo_UnlockRequest.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_UnlockRequest proto.InternalMessageInfo
+
+func (m *UnlockRequest) GetKey() []byte {
+	if m != nil {
+		return m.Key
+	}
+	return nil
+}
+
+type UnlockResponse struct {
+	Header               *etcdserverpb.ResponseHeader `protobuf:"bytes,1,opt,name=header,proto3" json:"header,omitempty"`
+	XXX_NoUnkeyedLiteral struct{}                     `json:"-"`
+	XXX_unrecognized     []byte                       `json:"-"`
+	XXX_sizecache        int32                        `json:"-"`
+}
+
+func (m *UnlockResponse) Reset()         { *m = UnlockResponse{} }
+func (m *UnlockResponse) String() string { return proto.CompactTextString(m) }
+func (*UnlockResponse) ProtoMessage()    {}
+func (*UnlockResponse) Descriptor() ([]byte, []int) {
+	return fileDescriptor_52389b3e2f253201, []int{3}
+}
+func (m *UnlockResponse) XXX_Unmarshal(b []byte) error {
+	return m.Unmarshal(b)
+}
+func (m *UnlockResponse) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	if deterministic {
+		return xxx_messageInfo_UnlockResponse.Marshal(b, m, deterministic)
+	} else {
+		b = b[:cap(b)]
+		n, err := m.MarshalToSizedBuffer(b)
+		if err != nil {
+			return nil, err
+		}
+		return b[:n], nil
+	}
+}
+func (m *UnlockResponse) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_UnlockResponse.Merge(m, src)
+}
+func (m *UnlockResponse) XXX_Size() int {
+	return m.Size()
+}
+func (m *UnlockResponse) XXX_DiscardUnknown() {
+	xxx_messageInfo_UnlockResponse.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_UnlockResponse proto.InternalMessageInfo
+
+func (m *UnlockResponse) GetHeader() *etcdserverpb.ResponseHeader {
+	if m != nil {
+		return m.Header
+	}
+	return nil
+}
+
+func init() {
+	proto.RegisterType((*LockRequest)(nil), "v3lockpb.LockRequest")
+	proto.RegisterType((*LockResponse)(nil), "v3lockpb.LockResponse")
+	proto.RegisterType((*UnlockRequest)(nil), "v3lockpb.UnlockRequest")
+	proto.RegisterType((*UnlockResponse)(nil), "v3lockpb.UnlockResponse")
+}
+
+func init() { proto.RegisterFile("v3lock.proto", fileDescriptor_52389b3e2f253201) }
+
+var fileDescriptor_52389b3e2f253201 = []byte{
+	// 356 bytes of a gzipped FileDescriptorProto
+	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0xa4, 0x92, 0xcd, 0x4a, 0xc3, 0x40,
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+	0x42, 0xd6, 0x22, 0xd9, 0x96, 0xb3, 0xf6, 0x2d, 0x3b, 0x51, 0x85, 0xf0, 0xd1, 0xe9, 0xcb, 0xcc,
+	0x66, 0xaf, 0x33, 0x9b, 0xbd, 0xcf, 0x6c, 0xf6, 0xf4, 0x61, 0x2f, 0x5d, 0x1f, 0x84, 0x48, 0xcd,
+	0xba, 0x23, 0xa4, 0x0d, 0x90, 0xba, 0xeb, 0x3c, 0x76, 0x3e, 0x03, 0x7a, 0x7c, 0x9d, 0x4f, 0x96,
+	0x69, 0x07, 0x75, 0xda, 0x80, 0xfe, 0x57, 0x00, 0x00, 0x00, 0xff, 0xff, 0xcb, 0x48, 0x31, 0x4a,
+	0x70, 0x02, 0x00, 0x00,
+}
+
+// Reference imports to suppress errors if they are not otherwise used.
+var _ context.Context
+var _ grpc.ClientConn
+
+// This is a compile-time assertion to ensure that this generated file
+// is compatible with the grpc package it is being compiled against.
+const _ = grpc.SupportPackageIsVersion4
+
+// LockClient is the client API for Lock service.
+//
+// For semantics around ctx use and closing/ending streaming RPCs, please refer to https://godoc.org/google.golang.org/grpc#ClientConn.NewStream.
+type LockClient interface {
+	// Lock acquires a distributed shared lock on a given named lock.
+	// On success, it will return a unique key that exists so long as the
+	// lock is held by the caller. This key can be used in conjunction with
+	// transactions to safely ensure updates to etcd only occur while holding
+	// lock ownership. The lock is held until Unlock is called on the key or the
+	// lease associate with the owner expires.
+	Lock(ctx context.Context, in *LockRequest, opts ...grpc.CallOption) (*LockResponse, error)
+	// Unlock takes a key returned by Lock and releases the hold on lock. The
+	// next Lock caller waiting for the lock will then be woken up and given
+	// ownership of the lock.
+	Unlock(ctx context.Context, in *UnlockRequest, opts ...grpc.CallOption) (*UnlockResponse, error)
+}
+
+type lockClient struct {
+	cc *grpc.ClientConn
+}
+
+func NewLockClient(cc *grpc.ClientConn) LockClient {
+	return &lockClient{cc}
+}
+
+func (c *lockClient) Lock(ctx context.Context, in *LockRequest, opts ...grpc.CallOption) (*LockResponse, error) {
+	out := new(LockResponse)
+	err := c.cc.Invoke(ctx, "/v3lockpb.Lock/Lock", in, out, opts...)
+	if err != nil {
+		return nil, err
+	}
+	return out, nil
+}
+
+func (c *lockClient) Unlock(ctx context.Context, in *UnlockRequest, opts ...grpc.CallOption) (*UnlockResponse, error) {
+	out := new(UnlockResponse)
+	err := c.cc.Invoke(ctx, "/v3lockpb.Lock/Unlock", in, out, opts...)
+	if err != nil {
+		return nil, err
+	}
+	return out, nil
+}
+
+// LockServer is the server API for Lock service.
+type LockServer interface {
+	// Lock acquires a distributed shared lock on a given named lock.
+	// On success, it will return a unique key that exists so long as the
+	// lock is held by the caller. This key can be used in conjunction with
+	// transactions to safely ensure updates to etcd only occur while holding
+	// lock ownership. The lock is held until Unlock is called on the key or the
+	// lease associate with the owner expires.
+	Lock(context.Context, *LockRequest) (*LockResponse, error)
+	// Unlock takes a key returned by Lock and releases the hold on lock. The
+	// next Lock caller waiting for the lock will then be woken up and given
+	// ownership of the lock.
+	Unlock(context.Context, *UnlockRequest) (*UnlockResponse, error)
+}
+
+// UnimplementedLockServer can be embedded to have forward compatible implementations.
+type UnimplementedLockServer struct {
+}
+
+func (*UnimplementedLockServer) Lock(ctx context.Context, req *LockRequest) (*LockResponse, error) {
+	return nil, status.Errorf(codes.Unimplemented, "method Lock not implemented")
+}
+func (*UnimplementedLockServer) Unlock(ctx context.Context, req *UnlockRequest) (*UnlockResponse, error) {
+	return nil, status.Errorf(codes.Unimplemented, "method Unlock not implemented")
+}
+
+func RegisterLockServer(s *grpc.Server, srv LockServer) {
+	s.RegisterService(&_Lock_serviceDesc, srv)
+}
+
+func _Lock_Lock_Handler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor grpc.UnaryServerInterceptor) (interface{}, error) {
+	in := new(LockRequest)
+	if err := dec(in); err != nil {
+		return nil, err
+	}
+	if interceptor == nil {
+		return srv.(LockServer).Lock(ctx, in)
+	}
+	info := &grpc.UnaryServerInfo{
+		Server:     srv,
+		FullMethod: "/v3lockpb.Lock/Lock",
+	}
+	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
+		return srv.(LockServer).Lock(ctx, req.(*LockRequest))
+	}
+	return interceptor(ctx, in, info, handler)
+}
+
+func _Lock_Unlock_Handler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor grpc.UnaryServerInterceptor) (interface{}, error) {
+	in := new(UnlockRequest)
+	if err := dec(in); err != nil {
+		return nil, err
+	}
+	if interceptor == nil {
+		return srv.(LockServer).Unlock(ctx, in)
+	}
+	info := &grpc.UnaryServerInfo{
+		Server:     srv,
+		FullMethod: "/v3lockpb.Lock/Unlock",
+	}
+	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
+		return srv.(LockServer).Unlock(ctx, req.(*UnlockRequest))
+	}
+	return interceptor(ctx, in, info, handler)
+}
+
+var _Lock_serviceDesc = grpc.ServiceDesc{
+	ServiceName: "v3lockpb.Lock",
+	HandlerType: (*LockServer)(nil),
+	Methods: []grpc.MethodDesc{
+		{
+			MethodName: "Lock",
+			Handler:    _Lock_Lock_Handler,
+		},
+		{
+			MethodName: "Unlock",
+			Handler:    _Lock_Unlock_Handler,
+		},
+	},
+	Streams:  []grpc.StreamDesc{},
+	Metadata: "v3lock.proto",
+}
+
+func (m *LockRequest) Marshal() (dAtA []byte, err error) {
+	size := m.Size()
+	dAtA = make([]byte, size)
+	n, err := m.MarshalToSizedBuffer(dAtA[:size])
+	if err != nil {
+		return nil, err
+	}
+	return dAtA[:n], nil
+}
+
+func (m *LockRequest) MarshalTo(dAtA []byte) (int, error) {
+	size := m.Size()
+	return m.MarshalToSizedBuffer(dAtA[:size])
+}
+
+func (m *LockRequest) MarshalToSizedBuffer(dAtA []byte) (int, error) {
+	i := len(dAtA)
+	_ = i
+	var l int
+	_ = l
+	if m.XXX_unrecognized != nil {
+		i -= len(m.XXX_unrecognized)
+		copy(dAtA[i:], m.XXX_unrecognized)
+	}
+	if m.Lease != 0 {
+		i = encodeVarintV3Lock(dAtA, i, uint64(m.Lease))
+		i--
+		dAtA[i] = 0x10
+	}
+	if len(m.Name) > 0 {
+		i -= len(m.Name)
+		copy(dAtA[i:], m.Name)
+		i = encodeVarintV3Lock(dAtA, i, uint64(len(m.Name)))
+		i--
+		dAtA[i] = 0xa
+	}
+	return len(dAtA) - i, nil
+}
+
+func (m *LockResponse) Marshal() (dAtA []byte, err error) {
+	size := m.Size()
+	dAtA = make([]byte, size)
+	n, err := m.MarshalToSizedBuffer(dAtA[:size])
+	if err != nil {
+		return nil, err
+	}
+	return dAtA[:n], nil
+}
+
+func (m *LockResponse) MarshalTo(dAtA []byte) (int, error) {
+	size := m.Size()
+	return m.MarshalToSizedBuffer(dAtA[:size])
+}
+
+func (m *LockResponse) MarshalToSizedBuffer(dAtA []byte) (int, error) {
+	i := len(dAtA)
+	_ = i
+	var l int
+	_ = l
+	if m.XXX_unrecognized != nil {
+		i -= len(m.XXX_unrecognized)
+		copy(dAtA[i:], m.XXX_unrecognized)
+	}
+	if len(m.Key) > 0 {
+		i -= len(m.Key)
+		copy(dAtA[i:], m.Key)
+		i = encodeVarintV3Lock(dAtA, i, uint64(len(m.Key)))
+		i--
+		dAtA[i] = 0x12
+	}
+	if m.Header != nil {
+		{
+			size, err := m.Header.MarshalToSizedBuffer(dAtA[:i])
+			if err != nil {
+				return 0, err
+			}
+			i -= size
+			i = encodeVarintV3Lock(dAtA, i, uint64(size))
+		}
+		i--
+		dAtA[i] = 0xa
+	}
+	return len(dAtA) - i, nil
+}
+
+func (m *UnlockRequest) Marshal() (dAtA []byte, err error) {
+	size := m.Size()
+	dAtA = make([]byte, size)
+	n, err := m.MarshalToSizedBuffer(dAtA[:size])
+	if err != nil {
+		return nil, err
+	}
+	return dAtA[:n], nil
+}
+
+func (m *UnlockRequest) MarshalTo(dAtA []byte) (int, error) {
+	size := m.Size()
+	return m.MarshalToSizedBuffer(dAtA[:size])
+}
+
+func (m *UnlockRequest) MarshalToSizedBuffer(dAtA []byte) (int, error) {
+	i := len(dAtA)
+	_ = i
+	var l int
+	_ = l
+	if m.XXX_unrecognized != nil {
+		i -= len(m.XXX_unrecognized)
+		copy(dAtA[i:], m.XXX_unrecognized)
+	}
+	if len(m.Key) > 0 {
+		i -= len(m.Key)
+		copy(dAtA[i:], m.Key)
+		i = encodeVarintV3Lock(dAtA, i, uint64(len(m.Key)))
+		i--
+		dAtA[i] = 0xa
+	}
+	return len(dAtA) - i, nil
+}
+
+func (m *UnlockResponse) Marshal() (dAtA []byte, err error) {
+	size := m.Size()
+	dAtA = make([]byte, size)
+	n, err := m.MarshalToSizedBuffer(dAtA[:size])
+	if err != nil {
+		return nil, err
+	}
+	return dAtA[:n], nil
+}
+
+func (m *UnlockResponse) MarshalTo(dAtA []byte) (int, error) {
+	size := m.Size()
+	return m.MarshalToSizedBuffer(dAtA[:size])
+}
+
+func (m *UnlockResponse) MarshalToSizedBuffer(dAtA []byte) (int, error) {
+	i := len(dAtA)
+	_ = i
+	var l int
+	_ = l
+	if m.XXX_unrecognized != nil {
+		i -= len(m.XXX_unrecognized)
+		copy(dAtA[i:], m.XXX_unrecognized)
+	}
+	if m.Header != nil {
+		{
+			size, err := m.Header.MarshalToSizedBuffer(dAtA[:i])
+			if err != nil {
+				return 0, err
+			}
+			i -= size
+			i = encodeVarintV3Lock(dAtA, i, uint64(size))
+		}
+		i--
+		dAtA[i] = 0xa
+	}
+	return len(dAtA) - i, nil
+}
+
+func encodeVarintV3Lock(dAtA []byte, offset int, v uint64) int {
+	offset -= sovV3Lock(v)
+	base := offset
+	for v >= 1<<7 {
+		dAtA[offset] = uint8(v&0x7f | 0x80)
+		v >>= 7
+		offset++
+	}
+	dAtA[offset] = uint8(v)
+	return base
+}
+func (m *LockRequest) Size() (n int) {
+	if m == nil {
+		return 0
+	}
+	var l int
+	_ = l
+	l = len(m.Name)
+	if l > 0 {
+		n += 1 + l + sovV3Lock(uint64(l))
+	}
+	if m.Lease != 0 {
+		n += 1 + sovV3Lock(uint64(m.Lease))
+	}
+	if m.XXX_unrecognized != nil {
+		n += len(m.XXX_unrecognized)
+	}
+	return n
+}
+
+func (m *LockResponse) Size() (n int) {
+	if m == nil {
+		return 0
+	}
+	var l int
+	_ = l
+	if m.Header != nil {
+		l = m.Header.Size()
+		n += 1 + l + sovV3Lock(uint64(l))
+	}
+	l = len(m.Key)
+	if l > 0 {
+		n += 1 + l + sovV3Lock(uint64(l))
+	}
+	if m.XXX_unrecognized != nil {
+		n += len(m.XXX_unrecognized)
+	}
+	return n
+}
+
+func (m *UnlockRequest) Size() (n int) {
+	if m == nil {
+		return 0
+	}
+	var l int
+	_ = l
+	l = len(m.Key)
+	if l > 0 {
+		n += 1 + l + sovV3Lock(uint64(l))
+	}
+	if m.XXX_unrecognized != nil {
+		n += len(m.XXX_unrecognized)
+	}
+	return n
+}
+
+func (m *UnlockResponse) Size() (n int) {
+	if m == nil {
+		return 0
+	}
+	var l int
+	_ = l
+	if m.Header != nil {
+		l = m.Header.Size()
+		n += 1 + l + sovV3Lock(uint64(l))
+	}
+	if m.XXX_unrecognized != nil {
+		n += len(m.XXX_unrecognized)
+	}
+	return n
+}
+
+func sovV3Lock(x uint64) (n int) {
+	return (math_bits.Len64(x|1) + 6) / 7
+}
+func sozV3Lock(x uint64) (n int) {
+	return sovV3Lock(uint64((x << 1) ^ uint64((int64(x) >> 63))))
+}
+func (m *LockRequest) Unmarshal(dAtA []byte) error {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		preIndex := iNdEx
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return ErrIntOverflowV3Lock
+			}
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= uint64(b&0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		if wireType == 4 {
+			return fmt.Errorf("proto: LockRequest: wiretype end group for non-group")
+		}
+		if fieldNum <= 0 {
+			return fmt.Errorf("proto: LockRequest: illegal tag %d (wire type %d)", fieldNum, wire)
+		}
+		switch fieldNum {
+		case 1:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Name", wireType)
+			}
+			var byteLen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowV3Lock
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				byteLen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if byteLen < 0 {
+				return ErrInvalidLengthV3Lock
+			}
+			postIndex := iNdEx + byteLen
+			if postIndex < 0 {
+				return ErrInvalidLengthV3Lock
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.Name = append(m.Name[:0], dAtA[iNdEx:postIndex]...)
+			if m.Name == nil {
+				m.Name = []byte{}
+			}
+			iNdEx = postIndex
+		case 2:
+			if wireType != 0 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Lease", wireType)
+			}
+			m.Lease = 0
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowV3Lock
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				m.Lease |= int64(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+		default:
+			iNdEx = preIndex
+			skippy, err := skipV3Lock(dAtA[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
+				return ErrInvalidLengthV3Lock
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.XXX_unrecognized = append(m.XXX_unrecognized, dAtA[iNdEx:iNdEx+skippy]...)
+			iNdEx += skippy
+		}
+	}
+
+	if iNdEx > l {
+		return io.ErrUnexpectedEOF
+	}
+	return nil
+}
+func (m *LockResponse) Unmarshal(dAtA []byte) error {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		preIndex := iNdEx
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return ErrIntOverflowV3Lock
+			}
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= uint64(b&0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		if wireType == 4 {
+			return fmt.Errorf("proto: LockResponse: wiretype end group for non-group")
+		}
+		if fieldNum <= 0 {
+			return fmt.Errorf("proto: LockResponse: illegal tag %d (wire type %d)", fieldNum, wire)
+		}
+		switch fieldNum {
+		case 1:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Header", wireType)
+			}
+			var msglen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowV3Lock
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				msglen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if msglen < 0 {
+				return ErrInvalidLengthV3Lock
+			}
+			postIndex := iNdEx + msglen
+			if postIndex < 0 {
+				return ErrInvalidLengthV3Lock
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			if m.Header == nil {
+				m.Header = &etcdserverpb.ResponseHeader{}
+			}
+			if err := m.Header.Unmarshal(dAtA[iNdEx:postIndex]); err != nil {
+				return err
+			}
+			iNdEx = postIndex
+		case 2:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Key", wireType)
+			}
+			var byteLen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowV3Lock
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				byteLen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if byteLen < 0 {
+				return ErrInvalidLengthV3Lock
+			}
+			postIndex := iNdEx + byteLen
+			if postIndex < 0 {
+				return ErrInvalidLengthV3Lock
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.Key = append(m.Key[:0], dAtA[iNdEx:postIndex]...)
+			if m.Key == nil {
+				m.Key = []byte{}
+			}
+			iNdEx = postIndex
+		default:
+			iNdEx = preIndex
+			skippy, err := skipV3Lock(dAtA[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
+				return ErrInvalidLengthV3Lock
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.XXX_unrecognized = append(m.XXX_unrecognized, dAtA[iNdEx:iNdEx+skippy]...)
+			iNdEx += skippy
+		}
+	}
+
+	if iNdEx > l {
+		return io.ErrUnexpectedEOF
+	}
+	return nil
+}
+func (m *UnlockRequest) Unmarshal(dAtA []byte) error {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		preIndex := iNdEx
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return ErrIntOverflowV3Lock
+			}
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= uint64(b&0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		if wireType == 4 {
+			return fmt.Errorf("proto: UnlockRequest: wiretype end group for non-group")
+		}
+		if fieldNum <= 0 {
+			return fmt.Errorf("proto: UnlockRequest: illegal tag %d (wire type %d)", fieldNum, wire)
+		}
+		switch fieldNum {
+		case 1:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Key", wireType)
+			}
+			var byteLen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowV3Lock
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				byteLen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if byteLen < 0 {
+				return ErrInvalidLengthV3Lock
+			}
+			postIndex := iNdEx + byteLen
+			if postIndex < 0 {
+				return ErrInvalidLengthV3Lock
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.Key = append(m.Key[:0], dAtA[iNdEx:postIndex]...)
+			if m.Key == nil {
+				m.Key = []byte{}
+			}
+			iNdEx = postIndex
+		default:
+			iNdEx = preIndex
+			skippy, err := skipV3Lock(dAtA[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
+				return ErrInvalidLengthV3Lock
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.XXX_unrecognized = append(m.XXX_unrecognized, dAtA[iNdEx:iNdEx+skippy]...)
+			iNdEx += skippy
+		}
+	}
+
+	if iNdEx > l {
+		return io.ErrUnexpectedEOF
+	}
+	return nil
+}
+func (m *UnlockResponse) Unmarshal(dAtA []byte) error {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		preIndex := iNdEx
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return ErrIntOverflowV3Lock
+			}
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= uint64(b&0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		if wireType == 4 {
+			return fmt.Errorf("proto: UnlockResponse: wiretype end group for non-group")
+		}
+		if fieldNum <= 0 {
+			return fmt.Errorf("proto: UnlockResponse: illegal tag %d (wire type %d)", fieldNum, wire)
+		}
+		switch fieldNum {
+		case 1:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Header", wireType)
+			}
+			var msglen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowV3Lock
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				msglen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if msglen < 0 {
+				return ErrInvalidLengthV3Lock
+			}
+			postIndex := iNdEx + msglen
+			if postIndex < 0 {
+				return ErrInvalidLengthV3Lock
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			if m.Header == nil {
+				m.Header = &etcdserverpb.ResponseHeader{}
+			}
+			if err := m.Header.Unmarshal(dAtA[iNdEx:postIndex]); err != nil {
+				return err
+			}
+			iNdEx = postIndex
+		default:
+			iNdEx = preIndex
+			skippy, err := skipV3Lock(dAtA[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
+				return ErrInvalidLengthV3Lock
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.XXX_unrecognized = append(m.XXX_unrecognized, dAtA[iNdEx:iNdEx+skippy]...)
+			iNdEx += skippy
+		}
+	}
+
+	if iNdEx > l {
+		return io.ErrUnexpectedEOF
+	}
+	return nil
+}
+func skipV3Lock(dAtA []byte) (n int, err error) {
+	l := len(dAtA)
+	iNdEx := 0
+	depth := 0
+	for iNdEx < l {
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return 0, ErrIntOverflowV3Lock
+			}
+			if iNdEx >= l {
+				return 0, io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= (uint64(b) & 0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		wireType := int(wire & 0x7)
+		switch wireType {
+		case 0:
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return 0, ErrIntOverflowV3Lock
+				}
+				if iNdEx >= l {
+					return 0, io.ErrUnexpectedEOF
+				}
+				iNdEx++
+				if dAtA[iNdEx-1] < 0x80 {
+					break
+				}
+			}
+		case 1:
+			iNdEx += 8
+		case 2:
+			var length int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return 0, ErrIntOverflowV3Lock
+				}
+				if iNdEx >= l {
+					return 0, io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				length |= (int(b) & 0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if length < 0 {
+				return 0, ErrInvalidLengthV3Lock
+			}
+			iNdEx += length
+		case 3:
+			depth++
+		case 4:
+			if depth == 0 {
+				return 0, ErrUnexpectedEndOfGroupV3Lock
+			}
+			depth--
+		case 5:
+			iNdEx += 4
+		default:
+			return 0, fmt.Errorf("proto: illegal wireType %d", wireType)
+		}
+		if iNdEx < 0 {
+			return 0, ErrInvalidLengthV3Lock
+		}
+		if depth == 0 {
+			return iNdEx, nil
+		}
+	}
+	return 0, io.ErrUnexpectedEOF
+}
+
+var (
+	ErrInvalidLengthV3Lock        = fmt.Errorf("proto: negative length found during unmarshaling")
+	ErrIntOverflowV3Lock          = fmt.Errorf("proto: integer overflow")
+	ErrUnexpectedEndOfGroupV3Lock = fmt.Errorf("proto: unexpected end of group")
+)
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3lock/v3lockpb/v3lock.proto b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3lock/v3lockpb/v3lock.proto
new file mode 100644
index 0000000..88a1c82
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3lock/v3lockpb/v3lock.proto
@@ -0,0 +1,67 @@
+syntax = "proto3";
+package v3lockpb;
+
+import "gogoproto/gogo.proto";
+import "etcd/api/etcdserverpb/rpc.proto";
+
+// for grpc-gateway
+import "google/api/annotations.proto";
+
+option go_package = "go.etcd.io/etcd/server/v3/etcdserver/api/v3lock/v3lockpb";
+
+option (gogoproto.marshaler_all) = true;
+option (gogoproto.unmarshaler_all) = true;
+
+// The lock service exposes client-side locking facilities as a gRPC interface.
+service Lock {
+  // Lock acquires a distributed shared lock on a given named lock.
+  // On success, it will return a unique key that exists so long as the
+  // lock is held by the caller. This key can be used in conjunction with
+  // transactions to safely ensure updates to etcd only occur while holding
+  // lock ownership. The lock is held until Unlock is called on the key or the
+  // lease associate with the owner expires.
+  rpc Lock(LockRequest) returns (LockResponse) {
+      option (google.api.http) = {
+        post: "/v3/lock/lock"
+        body: "*"
+    };
+  }
+
+  // Unlock takes a key returned by Lock and releases the hold on lock. The
+  // next Lock caller waiting for the lock will then be woken up and given
+  // ownership of the lock.
+  rpc Unlock(UnlockRequest) returns (UnlockResponse) {
+      option (google.api.http) = {
+        post: "/v3/lock/unlock"
+        body: "*"
+    };
+  }
+}
+
+message LockRequest {
+  // name is the identifier for the distributed shared lock to be acquired.
+  bytes name = 1;
+  // lease is the ID of the lease that will be attached to ownership of the
+  // lock. If the lease expires or is revoked and currently holds the lock,
+  // the lock is automatically released. Calls to Lock with the same lease will
+  // be treated as a single acquisition; locking twice with the same lease is a
+  // no-op.
+  int64 lease = 2;
+}
+
+message LockResponse {
+  etcdserverpb.ResponseHeader header = 1;
+  // key is a key that will exist on etcd for the duration that the Lock caller
+  // owns the lock. Users should not modify this key or the lock may exhibit
+  // undefined behavior.
+  bytes key = 2;
+}
+
+message UnlockRequest {
+  // key is the lock ownership key granted by Lock.
+  bytes key = 1;
+}
+
+message UnlockResponse {
+  etcdserverpb.ResponseHeader header = 1;
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/auth.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/auth.go
new file mode 100644
index 0000000..6c5db76
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/auth.go
@@ -0,0 +1,187 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v3rpc
+
+import (
+	"context"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/server/v3/auth"
+	"go.etcd.io/etcd/server/v3/etcdserver"
+)
+
+type AuthServer struct {
+	authenticator etcdserver.Authenticator
+}
+
+func NewAuthServer(s *etcdserver.EtcdServer) *AuthServer {
+	return &AuthServer{authenticator: s}
+}
+
+func (as *AuthServer) AuthEnable(ctx context.Context, r *pb.AuthEnableRequest) (*pb.AuthEnableResponse, error) {
+	resp, err := as.authenticator.AuthEnable(ctx, r)
+	if err != nil {
+		return nil, togRPCError(err)
+	}
+	return resp, nil
+}
+
+func (as *AuthServer) AuthDisable(ctx context.Context, r *pb.AuthDisableRequest) (*pb.AuthDisableResponse, error) {
+	resp, err := as.authenticator.AuthDisable(ctx, r)
+	if err != nil {
+		return nil, togRPCError(err)
+	}
+	return resp, nil
+}
+
+func (as *AuthServer) AuthStatus(ctx context.Context, r *pb.AuthStatusRequest) (*pb.AuthStatusResponse, error) {
+	resp, err := as.authenticator.AuthStatus(ctx, r)
+	if err != nil {
+		return nil, togRPCError(err)
+	}
+	return resp, nil
+}
+
+func (as *AuthServer) Authenticate(ctx context.Context, r *pb.AuthenticateRequest) (*pb.AuthenticateResponse, error) {
+	resp, err := as.authenticator.Authenticate(ctx, r)
+	if err != nil {
+		return nil, togRPCError(err)
+	}
+	return resp, nil
+}
+
+func (as *AuthServer) RoleAdd(ctx context.Context, r *pb.AuthRoleAddRequest) (*pb.AuthRoleAddResponse, error) {
+	resp, err := as.authenticator.RoleAdd(ctx, r)
+	if err != nil {
+		return nil, togRPCError(err)
+	}
+	return resp, nil
+}
+
+func (as *AuthServer) RoleDelete(ctx context.Context, r *pb.AuthRoleDeleteRequest) (*pb.AuthRoleDeleteResponse, error) {
+	resp, err := as.authenticator.RoleDelete(ctx, r)
+	if err != nil {
+		return nil, togRPCError(err)
+	}
+	return resp, nil
+}
+
+func (as *AuthServer) RoleGet(ctx context.Context, r *pb.AuthRoleGetRequest) (*pb.AuthRoleGetResponse, error) {
+	resp, err := as.authenticator.RoleGet(ctx, r)
+	if err != nil {
+		return nil, togRPCError(err)
+	}
+	return resp, nil
+}
+
+func (as *AuthServer) RoleList(ctx context.Context, r *pb.AuthRoleListRequest) (*pb.AuthRoleListResponse, error) {
+	resp, err := as.authenticator.RoleList(ctx, r)
+	if err != nil {
+		return nil, togRPCError(err)
+	}
+	return resp, nil
+}
+
+func (as *AuthServer) RoleRevokePermission(ctx context.Context, r *pb.AuthRoleRevokePermissionRequest) (*pb.AuthRoleRevokePermissionResponse, error) {
+	resp, err := as.authenticator.RoleRevokePermission(ctx, r)
+	if err != nil {
+		return nil, togRPCError(err)
+	}
+	return resp, nil
+}
+
+func (as *AuthServer) RoleGrantPermission(ctx context.Context, r *pb.AuthRoleGrantPermissionRequest) (*pb.AuthRoleGrantPermissionResponse, error) {
+	resp, err := as.authenticator.RoleGrantPermission(ctx, r)
+	if err != nil {
+		return nil, togRPCError(err)
+	}
+	return resp, nil
+}
+
+func (as *AuthServer) UserAdd(ctx context.Context, r *pb.AuthUserAddRequest) (*pb.AuthUserAddResponse, error) {
+	resp, err := as.authenticator.UserAdd(ctx, r)
+	if err != nil {
+		return nil, togRPCError(err)
+	}
+	return resp, nil
+}
+
+func (as *AuthServer) UserDelete(ctx context.Context, r *pb.AuthUserDeleteRequest) (*pb.AuthUserDeleteResponse, error) {
+	resp, err := as.authenticator.UserDelete(ctx, r)
+	if err != nil {
+		return nil, togRPCError(err)
+	}
+	return resp, nil
+}
+
+func (as *AuthServer) UserGet(ctx context.Context, r *pb.AuthUserGetRequest) (*pb.AuthUserGetResponse, error) {
+	resp, err := as.authenticator.UserGet(ctx, r)
+	if err != nil {
+		return nil, togRPCError(err)
+	}
+	return resp, nil
+}
+
+func (as *AuthServer) UserList(ctx context.Context, r *pb.AuthUserListRequest) (*pb.AuthUserListResponse, error) {
+	resp, err := as.authenticator.UserList(ctx, r)
+	if err != nil {
+		return nil, togRPCError(err)
+	}
+	return resp, nil
+}
+
+func (as *AuthServer) UserGrantRole(ctx context.Context, r *pb.AuthUserGrantRoleRequest) (*pb.AuthUserGrantRoleResponse, error) {
+	resp, err := as.authenticator.UserGrantRole(ctx, r)
+	if err != nil {
+		return nil, togRPCError(err)
+	}
+	return resp, nil
+}
+
+func (as *AuthServer) UserRevokeRole(ctx context.Context, r *pb.AuthUserRevokeRoleRequest) (*pb.AuthUserRevokeRoleResponse, error) {
+	resp, err := as.authenticator.UserRevokeRole(ctx, r)
+	if err != nil {
+		return nil, togRPCError(err)
+	}
+	return resp, nil
+}
+
+func (as *AuthServer) UserChangePassword(ctx context.Context, r *pb.AuthUserChangePasswordRequest) (*pb.AuthUserChangePasswordResponse, error) {
+	resp, err := as.authenticator.UserChangePassword(ctx, r)
+	if err != nil {
+		return nil, togRPCError(err)
+	}
+	return resp, nil
+}
+
+type AuthGetter interface {
+	AuthInfoFromCtx(ctx context.Context) (*auth.AuthInfo, error)
+	AuthStore() auth.AuthStore
+}
+
+type AuthAdmin struct {
+	ag AuthGetter
+}
+
+// isPermitted verifies the user has admin privilege.
+// Only users with "root" role are permitted.
+func (aa *AuthAdmin) isPermitted(ctx context.Context) error {
+	authInfo, err := aa.ag.AuthInfoFromCtx(ctx)
+	if err != nil {
+		return err
+	}
+
+	return aa.ag.AuthStore().IsAdminPermitted(authInfo)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/codec.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/codec.go
new file mode 100644
index 0000000..1bbed83
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/codec.go
@@ -0,0 +1,34 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v3rpc
+
+import "github.com/golang/protobuf/proto"
+
+type codec struct{}
+
+func (c *codec) Marshal(v any) ([]byte, error) {
+	b, err := proto.Marshal(v.(proto.Message))
+	sentBytes.Add(float64(len(b)))
+	return b, err
+}
+
+func (c *codec) Unmarshal(data []byte, v any) error {
+	receivedBytes.Add(float64(len(data)))
+	return proto.Unmarshal(data, v.(proto.Message))
+}
+
+func (c *codec) String() string {
+	return "proto"
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/grpc.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/grpc.go
new file mode 100644
index 0000000..efa1514
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/grpc.go
@@ -0,0 +1,97 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v3rpc
+
+import (
+	"crypto/tls"
+	"math"
+
+	grpc_prometheus "github.com/grpc-ecosystem/go-grpc-middleware/providers/prometheus"
+	"github.com/prometheus/client_golang/prometheus"
+	"go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc"
+	"go.uber.org/zap"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/health"
+	healthpb "google.golang.org/grpc/health/grpc_health_v1"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/client/v3/credentials"
+	"go.etcd.io/etcd/server/v3/etcdserver"
+)
+
+const (
+	maxSendBytes = math.MaxInt32
+)
+
+func Server(s *etcdserver.EtcdServer, tls *tls.Config, interceptor grpc.UnaryServerInterceptor, gopts ...grpc.ServerOption) *grpc.Server {
+	var opts []grpc.ServerOption
+	opts = append(opts, grpc.CustomCodec(&codec{}))
+	if tls != nil {
+		opts = append(opts, grpc.Creds(credentials.NewTransportCredential(tls)))
+	}
+
+	var mopts []grpc_prometheus.ServerMetricsOption
+	if s.Cfg.Metrics == "extensive" {
+		mopts = append(mopts, grpc_prometheus.WithServerHandlingTimeHistogram())
+	}
+	serverMetrics := grpc_prometheus.NewServerMetrics(mopts...)
+	err := prometheus.Register(serverMetrics)
+	if err != nil {
+		s.Cfg.Logger.Warn("etcdserver: failed to register grpc metrics", zap.Error(err))
+	}
+
+	chainUnaryInterceptors := []grpc.UnaryServerInterceptor{
+		newLogUnaryInterceptor(s),
+		newUnaryInterceptor(s),
+		serverMetrics.UnaryServerInterceptor(),
+	}
+	if interceptor != nil {
+		chainUnaryInterceptors = append(chainUnaryInterceptors, interceptor)
+	}
+
+	chainStreamInterceptors := []grpc.StreamServerInterceptor{
+		newStreamInterceptor(s),
+		serverMetrics.StreamServerInterceptor(),
+	}
+
+	if s.Cfg.EnableDistributedTracing {
+		opts = append(opts, grpc.StatsHandler(otelgrpc.NewServerHandler(s.Cfg.TracerOptions...)))
+	}
+
+	opts = append(opts, grpc.ChainUnaryInterceptor(chainUnaryInterceptors...))
+	opts = append(opts, grpc.ChainStreamInterceptor(chainStreamInterceptors...))
+
+	opts = append(opts, grpc.MaxRecvMsgSize(int(s.Cfg.MaxRequestBytesWithOverhead())))
+	opts = append(opts, grpc.MaxSendMsgSize(maxSendBytes))
+	opts = append(opts, grpc.MaxConcurrentStreams(s.Cfg.MaxConcurrentStreams))
+
+	grpcServer := grpc.NewServer(append(opts, gopts...)...)
+
+	pb.RegisterKVServer(grpcServer, NewQuotaKVServer(s))
+	pb.RegisterWatchServer(grpcServer, NewWatchServer(s))
+	pb.RegisterLeaseServer(grpcServer, NewQuotaLeaseServer(s))
+	pb.RegisterClusterServer(grpcServer, NewClusterServer(s))
+	pb.RegisterAuthServer(grpcServer, NewAuthServer(s))
+
+	hsrv := health.NewServer()
+	healthNotifier := newHealthNotifier(hsrv, s)
+	healthpb.RegisterHealthServer(grpcServer, hsrv)
+	pb.RegisterMaintenanceServer(grpcServer, NewMaintenanceServer(s, healthNotifier))
+
+	// set zero values for metrics registered for this grpc server
+	serverMetrics.InitializeMetrics(grpcServer)
+
+	return grpcServer
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/header.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/header.go
new file mode 100644
index 0000000..8fe4e58
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/header.go
@@ -0,0 +1,50 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v3rpc
+
+import (
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/server/v3/etcdserver"
+	"go.etcd.io/etcd/server/v3/etcdserver/apply"
+)
+
+type header struct {
+	clusterID int64
+	memberID  int64
+	sg        apply.RaftStatusGetter
+	rev       func() int64
+}
+
+func newHeader(s *etcdserver.EtcdServer) header {
+	return header{
+		clusterID: int64(s.Cluster().ID()),
+		memberID:  int64(s.MemberID()),
+		sg:        s,
+		rev:       func() int64 { return s.KV().Rev() },
+	}
+}
+
+// fill populates pb.ResponseHeader using etcdserver information
+func (h *header) fill(rh *pb.ResponseHeader) {
+	if rh == nil {
+		panic("unexpected nil resp.Header")
+	}
+	rh.ClusterId = uint64(h.clusterID)
+	rh.MemberId = uint64(h.memberID)
+	rh.RaftTerm = h.sg.Term()
+	if rh.Revision == 0 {
+		rh.Revision = h.rev()
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/health.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/health.go
new file mode 100644
index 0000000..2861e11
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/health.go
@@ -0,0 +1,79 @@
+// Copyright 2023 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v3rpc
+
+import (
+	"go.uber.org/zap"
+	"google.golang.org/grpc/health"
+	healthpb "google.golang.org/grpc/health/grpc_health_v1"
+
+	"go.etcd.io/etcd/server/v3/etcdserver"
+	"go.etcd.io/etcd/server/v3/features"
+)
+
+const (
+	allGRPCServices = ""
+)
+
+type notifier interface {
+	defragStarted()
+	defragFinished()
+}
+
+func newHealthNotifier(hs *health.Server, s *etcdserver.EtcdServer) notifier {
+	if hs == nil {
+		panic("unexpected nil gRPC health server")
+	}
+	hc := &healthNotifier{hs: hs, lg: s.Logger(), stopGRPCServiceOnDefrag: s.FeatureEnabled(features.StopGRPCServiceOnDefrag)}
+	// set grpc health server as serving status blindly since
+	// the grpc server will serve iff s.ReadyNotify() is closed.
+	hc.startServe()
+	return hc
+}
+
+type healthNotifier struct {
+	hs *health.Server
+	lg *zap.Logger
+
+	stopGRPCServiceOnDefrag bool
+}
+
+func (hc *healthNotifier) defragStarted() {
+	if !hc.stopGRPCServiceOnDefrag {
+		return
+	}
+	hc.stopServe("defrag is active")
+}
+
+func (hc *healthNotifier) defragFinished() { hc.startServe() }
+
+func (hc *healthNotifier) startServe() {
+	hc.lg.Info(
+		"grpc service status changed",
+		zap.String("service", allGRPCServices),
+		zap.String("status", healthpb.HealthCheckResponse_SERVING.String()),
+	)
+	hc.hs.SetServingStatus(allGRPCServices, healthpb.HealthCheckResponse_SERVING)
+}
+
+func (hc *healthNotifier) stopServe(reason string) {
+	hc.lg.Warn(
+		"grpc service status changed",
+		zap.String("service", allGRPCServices),
+		zap.String("status", healthpb.HealthCheckResponse_NOT_SERVING.String()),
+		zap.String("reason", reason),
+	)
+	hc.hs.SetServingStatus(allGRPCServices, healthpb.HealthCheckResponse_NOT_SERVING)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/interceptor.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/interceptor.go
new file mode 100644
index 0000000..697d0b0
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/interceptor.go
@@ -0,0 +1,353 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v3rpc
+
+import (
+	"context"
+	"sync"
+	"time"
+	"unicode/utf8"
+
+	"go.uber.org/zap"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/metadata"
+	"google.golang.org/grpc/peer"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/api/v3/v3rpc/rpctypes"
+	"go.etcd.io/etcd/client/pkg/v3/types"
+	"go.etcd.io/etcd/server/v3/etcdserver"
+	"go.etcd.io/etcd/server/v3/etcdserver/api"
+	"go.etcd.io/raft/v3"
+)
+
+const (
+	maxNoLeaderCnt = 3
+	snapshotMethod = "/etcdserverpb.Maintenance/Snapshot"
+)
+
+type streamsMap struct {
+	mu      sync.Mutex
+	streams map[grpc.ServerStream]struct{}
+}
+
+func newUnaryInterceptor(s *etcdserver.EtcdServer) grpc.UnaryServerInterceptor {
+	return func(ctx context.Context, req any, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (any, error) {
+		if !api.IsCapabilityEnabled(api.V3rpcCapability) {
+			return nil, rpctypes.ErrGRPCNotCapable
+		}
+
+		if s.IsMemberExist(s.MemberID()) && s.IsLearner() && !isRPCSupportedForLearner(req) {
+			return nil, rpctypes.ErrGRPCNotSupportedForLearner
+		}
+
+		md, ok := metadata.FromIncomingContext(ctx)
+		if ok {
+			ver, vs := "unknown", md.Get(rpctypes.MetadataClientAPIVersionKey)
+			if len(vs) > 0 {
+				ver = vs[0]
+			}
+			if !utf8.ValidString(ver) {
+				return nil, rpctypes.ErrGRPCInvalidClientAPIVersion
+			}
+			clientRequests.WithLabelValues("unary", ver).Inc()
+
+			if ks := md[rpctypes.MetadataRequireLeaderKey]; len(ks) > 0 && ks[0] == rpctypes.MetadataHasLeader {
+				if s.Leader() == types.ID(raft.None) {
+					return nil, rpctypes.ErrGRPCNoLeader
+				}
+			}
+		}
+
+		return handler(ctx, req)
+	}
+}
+
+func newLogUnaryInterceptor(s *etcdserver.EtcdServer) grpc.UnaryServerInterceptor {
+	return func(ctx context.Context, req any, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (any, error) {
+		startTime := time.Now()
+		resp, err := handler(ctx, req)
+		lg := s.Logger()
+		if lg != nil { // acquire stats if debug level is enabled or RequestInfo is expensive
+			defer logUnaryRequestStats(ctx, lg, s.Cfg.WarningUnaryRequestDuration, info, startTime, req, resp)
+		}
+		return resp, err
+	}
+}
+
+func logUnaryRequestStats(ctx context.Context, lg *zap.Logger, warnLatency time.Duration, info *grpc.UnaryServerInfo, startTime time.Time, req any, resp any) {
+	duration := time.Since(startTime)
+	var enabledDebugLevel, expensiveRequest bool
+	if lg.Core().Enabled(zap.DebugLevel) {
+		enabledDebugLevel = true
+	}
+	if duration > warnLatency {
+		expensiveRequest = true
+	}
+	if !enabledDebugLevel && !expensiveRequest {
+		return
+	}
+	remote := "No remote client info."
+	peerInfo, ok := peer.FromContext(ctx)
+	if ok {
+		remote = peerInfo.Addr.String()
+	}
+	responseType := info.FullMethod
+	var reqCount, respCount int64
+	var reqSize, respSize int
+	var reqContent string
+	switch _resp := resp.(type) {
+	case *pb.RangeResponse:
+		_req, ok := req.(*pb.RangeRequest)
+		if ok {
+			reqCount = 0
+			reqSize = _req.Size()
+			reqContent = _req.String()
+		}
+		if _resp != nil {
+			respCount = _resp.GetCount()
+			respSize = _resp.Size()
+		}
+	case *pb.PutResponse:
+		_req, ok := req.(*pb.PutRequest)
+		if ok {
+			reqCount = 1
+			reqSize = _req.Size()
+			reqContent = pb.NewLoggablePutRequest(_req).String()
+			// redact value field from request content, see PR #9821
+		}
+		if _resp != nil {
+			respCount = 0
+			respSize = _resp.Size()
+		}
+	case *pb.DeleteRangeResponse:
+		_req, ok := req.(*pb.DeleteRangeRequest)
+		if ok {
+			reqCount = 0
+			reqSize = _req.Size()
+			reqContent = _req.String()
+		}
+		if _resp != nil {
+			respCount = _resp.GetDeleted()
+			respSize = _resp.Size()
+		}
+	case *pb.TxnResponse:
+		_req, ok := req.(*pb.TxnRequest)
+		if ok && _resp != nil {
+			if _resp.GetSucceeded() { // determine the 'actual' count and size of request based on success or failure
+				reqCount = int64(len(_req.GetSuccess()))
+				reqSize = 0
+				for _, r := range _req.GetSuccess() {
+					reqSize += r.Size()
+				}
+			} else {
+				reqCount = int64(len(_req.GetFailure()))
+				reqSize = 0
+				for _, r := range _req.GetFailure() {
+					reqSize += r.Size()
+				}
+			}
+			reqContent = pb.NewLoggableTxnRequest(_req).String()
+			// redact value field from request content, see PR #9821
+		}
+		if _resp != nil {
+			respCount = 0
+			respSize = _resp.Size()
+		}
+	default:
+		reqCount = -1
+		reqSize = -1
+		respCount = -1
+		respSize = -1
+	}
+
+	if enabledDebugLevel {
+		logGenericRequestStats(lg, startTime, duration, remote, responseType, reqCount, reqSize, respCount, respSize, reqContent)
+	} else if expensiveRequest {
+		logExpensiveRequestStats(lg, startTime, duration, remote, responseType, reqCount, reqSize, respCount, respSize, reqContent)
+	}
+}
+
+func logGenericRequestStats(lg *zap.Logger, startTime time.Time, duration time.Duration, remote string, responseType string,
+	reqCount int64, reqSize int, respCount int64, respSize int, reqContent string,
+) {
+	lg.Debug("request stats",
+		zap.Time("start time", startTime),
+		zap.Duration("time spent", duration),
+		zap.String("remote", remote),
+		zap.String("response type", responseType),
+		zap.Int64("request count", reqCount),
+		zap.Int("request size", reqSize),
+		zap.Int64("response count", respCount),
+		zap.Int("response size", respSize),
+		zap.String("request content", reqContent),
+	)
+}
+
+func logExpensiveRequestStats(lg *zap.Logger, startTime time.Time, duration time.Duration, remote string, responseType string,
+	reqCount int64, reqSize int, respCount int64, respSize int, reqContent string,
+) {
+	lg.Warn("request stats",
+		zap.Time("start time", startTime),
+		zap.Duration("time spent", duration),
+		zap.String("remote", remote),
+		zap.String("response type", responseType),
+		zap.Int64("request count", reqCount),
+		zap.Int("request size", reqSize),
+		zap.Int64("response count", respCount),
+		zap.Int("response size", respSize),
+		zap.String("request content", reqContent),
+	)
+}
+
+func newStreamInterceptor(s *etcdserver.EtcdServer) grpc.StreamServerInterceptor {
+	smap := monitorLeader(s)
+
+	return func(srv any, ss grpc.ServerStream, info *grpc.StreamServerInfo, handler grpc.StreamHandler) error {
+		if !api.IsCapabilityEnabled(api.V3rpcCapability) {
+			return rpctypes.ErrGRPCNotCapable
+		}
+
+		if s.IsMemberExist(s.MemberID()) && s.IsLearner() && info.FullMethod != snapshotMethod { // learner does not support stream RPC except Snapshot
+			return rpctypes.ErrGRPCNotSupportedForLearner
+		}
+
+		md, ok := metadata.FromIncomingContext(ss.Context())
+		if ok {
+			ver, vs := "unknown", md.Get(rpctypes.MetadataClientAPIVersionKey)
+			if len(vs) > 0 {
+				ver = vs[0]
+			}
+			if !utf8.ValidString(ver) {
+				return rpctypes.ErrGRPCInvalidClientAPIVersion
+			}
+			clientRequests.WithLabelValues("stream", ver).Inc()
+
+			if ks := md[rpctypes.MetadataRequireLeaderKey]; len(ks) > 0 && ks[0] == rpctypes.MetadataHasLeader {
+				if s.Leader() == types.ID(raft.None) {
+					return rpctypes.ErrGRPCNoLeader
+				}
+
+				ctx := newCancellableContext(ss.Context())
+				ss = serverStreamWithCtx{ctx: ctx, ServerStream: ss}
+
+				smap.mu.Lock()
+				smap.streams[ss] = struct{}{}
+				smap.mu.Unlock()
+
+				defer func() {
+					smap.mu.Lock()
+					delete(smap.streams, ss)
+					smap.mu.Unlock()
+					// TODO: investigate whether the reason for cancellation here is useful to know
+					ctx.Cancel(nil)
+				}()
+			}
+		}
+
+		return handler(srv, ss)
+	}
+}
+
+// cancellableContext wraps a context with new cancellable context that allows a
+// specific cancellation error to be preserved and later retrieved using the
+// Context.Err() function. This is so downstream context users can disambiguate
+// the reason for the cancellation which could be from the client (for example)
+// or from this interceptor code.
+type cancellableContext struct {
+	context.Context
+
+	lock         sync.RWMutex
+	cancel       context.CancelFunc
+	cancelReason error
+}
+
+func newCancellableContext(parent context.Context) *cancellableContext {
+	ctx, cancel := context.WithCancel(parent)
+	return &cancellableContext{
+		Context: ctx,
+		cancel:  cancel,
+	}
+}
+
+// Cancel stores the cancellation reason and then delegates to context.WithCancel
+// against the parent context.
+func (c *cancellableContext) Cancel(reason error) {
+	c.lock.Lock()
+	c.cancelReason = reason
+	c.lock.Unlock()
+	c.cancel()
+}
+
+// Err will return the preserved cancel reason error if present, and will
+// otherwise return the underlying error from the parent context.
+func (c *cancellableContext) Err() error {
+	c.lock.RLock()
+	defer c.lock.RUnlock()
+	if c.cancelReason != nil {
+		return c.cancelReason
+	}
+	return c.Context.Err()
+}
+
+type serverStreamWithCtx struct {
+	grpc.ServerStream
+
+	// ctx is used so that we can preserve a reason for cancellation.
+	ctx *cancellableContext
+}
+
+func (ssc serverStreamWithCtx) Context() context.Context { return ssc.ctx }
+
+func monitorLeader(s *etcdserver.EtcdServer) *streamsMap {
+	smap := &streamsMap{
+		streams: make(map[grpc.ServerStream]struct{}),
+	}
+
+	s.GoAttach(func() {
+		election := time.Duration(s.Cfg.TickMs) * time.Duration(s.Cfg.ElectionTicks) * time.Millisecond
+		noLeaderCnt := 0
+
+		for {
+			select {
+			case <-s.StoppingNotify():
+				return
+			case <-time.After(election):
+				if s.Leader() == types.ID(raft.None) {
+					noLeaderCnt++
+				} else {
+					noLeaderCnt = 0
+				}
+
+				// We are more conservative on canceling existing streams. Reconnecting streams
+				// cost much more than just rejecting new requests. So we wait until the member
+				// cannot find a leader for maxNoLeaderCnt election timeouts to cancel existing streams.
+				if noLeaderCnt >= maxNoLeaderCnt {
+					smap.mu.Lock()
+					for ss := range smap.streams {
+						if ssWithCtx, ok := ss.(serverStreamWithCtx); ok {
+							ssWithCtx.ctx.Cancel(rpctypes.ErrGRPCNoLeader)
+							<-ss.Context().Done()
+						}
+					}
+					smap.streams = make(map[grpc.ServerStream]struct{})
+					smap.mu.Unlock()
+				}
+			}
+		}
+	})
+
+	return smap
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/key.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/key.go
new file mode 100644
index 0000000..2c1de2a
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/key.go
@@ -0,0 +1,280 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package v3rpc implements etcd v3 RPC system based on gRPC.
+package v3rpc
+
+import (
+	"context"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/api/v3/v3rpc/rpctypes"
+	"go.etcd.io/etcd/pkg/v3/adt"
+	"go.etcd.io/etcd/server/v3/etcdserver"
+)
+
+type kvServer struct {
+	hdr header
+	kv  etcdserver.RaftKV
+	// maxTxnOps is the max operations per txn.
+	// e.g suppose maxTxnOps = 128.
+	// Txn.Success can have at most 128 operations,
+	// and Txn.Failure can have at most 128 operations.
+	maxTxnOps uint
+}
+
+func NewKVServer(s *etcdserver.EtcdServer) pb.KVServer {
+	return &kvServer{hdr: newHeader(s), kv: s, maxTxnOps: s.Cfg.MaxTxnOps}
+}
+
+func (s *kvServer) Range(ctx context.Context, r *pb.RangeRequest) (*pb.RangeResponse, error) {
+	if err := checkRangeRequest(r); err != nil {
+		return nil, err
+	}
+
+	resp, err := s.kv.Range(ctx, r)
+	if err != nil {
+		return nil, togRPCError(err)
+	}
+
+	s.hdr.fill(resp.Header)
+	return resp, nil
+}
+
+func (s *kvServer) Put(ctx context.Context, r *pb.PutRequest) (*pb.PutResponse, error) {
+	if err := checkPutRequest(r); err != nil {
+		return nil, err
+	}
+
+	resp, err := s.kv.Put(ctx, r)
+	if err != nil {
+		return nil, togRPCError(err)
+	}
+
+	s.hdr.fill(resp.Header)
+	return resp, nil
+}
+
+func (s *kvServer) DeleteRange(ctx context.Context, r *pb.DeleteRangeRequest) (*pb.DeleteRangeResponse, error) {
+	if err := checkDeleteRequest(r); err != nil {
+		return nil, err
+	}
+
+	resp, err := s.kv.DeleteRange(ctx, r)
+	if err != nil {
+		return nil, togRPCError(err)
+	}
+
+	s.hdr.fill(resp.Header)
+	return resp, nil
+}
+
+func (s *kvServer) Txn(ctx context.Context, r *pb.TxnRequest) (*pb.TxnResponse, error) {
+	if err := checkTxnRequest(r, int(s.maxTxnOps)); err != nil {
+		return nil, err
+	}
+	// check for forbidden put/del overlaps after checking request to avoid quadratic blowup
+	if _, _, err := checkIntervals(r.Success); err != nil {
+		return nil, err
+	}
+	if _, _, err := checkIntervals(r.Failure); err != nil {
+		return nil, err
+	}
+
+	resp, err := s.kv.Txn(ctx, r)
+	if err != nil {
+		return nil, togRPCError(err)
+	}
+
+	s.hdr.fill(resp.Header)
+	return resp, nil
+}
+
+func (s *kvServer) Compact(ctx context.Context, r *pb.CompactionRequest) (*pb.CompactionResponse, error) {
+	resp, err := s.kv.Compact(ctx, r)
+	if err != nil {
+		return nil, togRPCError(err)
+	}
+
+	s.hdr.fill(resp.Header)
+	return resp, nil
+}
+
+func checkRangeRequest(r *pb.RangeRequest) error {
+	if len(r.Key) == 0 {
+		return rpctypes.ErrGRPCEmptyKey
+	}
+
+	if _, ok := pb.RangeRequest_SortOrder_name[int32(r.SortOrder)]; !ok {
+		return rpctypes.ErrGRPCInvalidSortOption
+	}
+
+	if _, ok := pb.RangeRequest_SortTarget_name[int32(r.SortTarget)]; !ok {
+		return rpctypes.ErrGRPCInvalidSortOption
+	}
+
+	return nil
+}
+
+func checkPutRequest(r *pb.PutRequest) error {
+	if len(r.Key) == 0 {
+		return rpctypes.ErrGRPCEmptyKey
+	}
+	if r.IgnoreValue && len(r.Value) != 0 {
+		return rpctypes.ErrGRPCValueProvided
+	}
+	if r.IgnoreLease && r.Lease != 0 {
+		return rpctypes.ErrGRPCLeaseProvided
+	}
+	return nil
+}
+
+func checkDeleteRequest(r *pb.DeleteRangeRequest) error {
+	if len(r.Key) == 0 {
+		return rpctypes.ErrGRPCEmptyKey
+	}
+	return nil
+}
+
+func checkTxnRequest(r *pb.TxnRequest, maxTxnOps int) error {
+	opc := len(r.Compare)
+	if opc < len(r.Success) {
+		opc = len(r.Success)
+	}
+	if opc < len(r.Failure) {
+		opc = len(r.Failure)
+	}
+	if opc > maxTxnOps {
+		return rpctypes.ErrGRPCTooManyOps
+	}
+
+	for _, c := range r.Compare {
+		if len(c.Key) == 0 {
+			return rpctypes.ErrGRPCEmptyKey
+		}
+	}
+	for _, u := range r.Success {
+		if err := checkRequestOp(u, maxTxnOps-opc); err != nil {
+			return err
+		}
+	}
+	for _, u := range r.Failure {
+		if err := checkRequestOp(u, maxTxnOps-opc); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+// checkIntervals tests whether puts and deletes overlap for a list of ops. If
+// there is an overlap, returns an error. If no overlap, return put and delete
+// sets for recursive evaluation.
+func checkIntervals(reqs []*pb.RequestOp) (map[string]struct{}, adt.IntervalTree, error) {
+	dels := adt.NewIntervalTree()
+
+	// collect deletes from this level; build first to check lower level overlapped puts
+	for _, req := range reqs {
+		tv, ok := req.Request.(*pb.RequestOp_RequestDeleteRange)
+		if !ok {
+			continue
+		}
+		dreq := tv.RequestDeleteRange
+		if dreq == nil {
+			continue
+		}
+		var iv adt.Interval
+		if len(dreq.RangeEnd) != 0 {
+			iv = adt.NewStringAffineInterval(string(dreq.Key), string(dreq.RangeEnd))
+		} else {
+			iv = adt.NewStringAffinePoint(string(dreq.Key))
+		}
+		dels.Insert(iv, struct{}{})
+	}
+
+	// collect children puts/deletes
+	puts := make(map[string]struct{})
+	for _, req := range reqs {
+		tv, ok := req.Request.(*pb.RequestOp_RequestTxn)
+		if !ok {
+			continue
+		}
+		putsThen, delsThen, err := checkIntervals(tv.RequestTxn.Success)
+		if err != nil {
+			return nil, dels, err
+		}
+		putsElse, delsElse, err := checkIntervals(tv.RequestTxn.Failure)
+		if err != nil {
+			return nil, dels, err
+		}
+		for k := range putsThen {
+			if _, ok := puts[k]; ok {
+				return nil, dels, rpctypes.ErrGRPCDuplicateKey
+			}
+			if dels.Intersects(adt.NewStringAffinePoint(k)) {
+				return nil, dels, rpctypes.ErrGRPCDuplicateKey
+			}
+			puts[k] = struct{}{}
+		}
+		for k := range putsElse {
+			if _, ok := puts[k]; ok {
+				// if key is from putsThen, overlap is OK since
+				// either then/else are mutually exclusive
+				if _, isSafe := putsThen[k]; !isSafe {
+					return nil, dels, rpctypes.ErrGRPCDuplicateKey
+				}
+			}
+			if dels.Intersects(adt.NewStringAffinePoint(k)) {
+				return nil, dels, rpctypes.ErrGRPCDuplicateKey
+			}
+			puts[k] = struct{}{}
+		}
+		dels.Union(delsThen, adt.NewStringAffineInterval("\x00", ""))
+		dels.Union(delsElse, adt.NewStringAffineInterval("\x00", ""))
+	}
+
+	// collect and check this level's puts
+	for _, req := range reqs {
+		tv, ok := req.Request.(*pb.RequestOp_RequestPut)
+		if !ok || tv.RequestPut == nil {
+			continue
+		}
+		k := string(tv.RequestPut.Key)
+		if _, ok := puts[k]; ok {
+			return nil, dels, rpctypes.ErrGRPCDuplicateKey
+		}
+		if dels.Intersects(adt.NewStringAffinePoint(k)) {
+			return nil, dels, rpctypes.ErrGRPCDuplicateKey
+		}
+		puts[k] = struct{}{}
+	}
+	return puts, dels, nil
+}
+
+func checkRequestOp(u *pb.RequestOp, maxTxnOps int) error {
+	// TODO: ensure only one of the field is set.
+	switch uv := u.Request.(type) {
+	case *pb.RequestOp_RequestRange:
+		return checkRangeRequest(uv.RequestRange)
+	case *pb.RequestOp_RequestPut:
+		return checkPutRequest(uv.RequestPut)
+	case *pb.RequestOp_RequestDeleteRange:
+		return checkDeleteRequest(uv.RequestDeleteRange)
+	case *pb.RequestOp_RequestTxn:
+		return checkTxnRequest(uv.RequestTxn, maxTxnOps)
+	default:
+		// empty op / nil entry
+		return rpctypes.ErrGRPCKeyNotFound
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/lease.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/lease.go
new file mode 100644
index 0000000..f51334e
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/lease.go
@@ -0,0 +1,157 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v3rpc
+
+import (
+	"context"
+	"errors"
+	"io"
+
+	"go.uber.org/zap"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/api/v3/v3rpc/rpctypes"
+	"go.etcd.io/etcd/server/v3/etcdserver"
+	"go.etcd.io/etcd/server/v3/lease"
+)
+
+type LeaseServer struct {
+	lg  *zap.Logger
+	hdr header
+	le  etcdserver.Lessor
+}
+
+func NewLeaseServer(s *etcdserver.EtcdServer) pb.LeaseServer {
+	srv := &LeaseServer{lg: s.Cfg.Logger, le: s, hdr: newHeader(s)}
+	if srv.lg == nil {
+		srv.lg = zap.NewNop()
+	}
+	return srv
+}
+
+func (ls *LeaseServer) LeaseGrant(ctx context.Context, cr *pb.LeaseGrantRequest) (*pb.LeaseGrantResponse, error) {
+	resp, err := ls.le.LeaseGrant(ctx, cr)
+	if err != nil {
+		return nil, togRPCError(err)
+	}
+	ls.hdr.fill(resp.Header)
+	return resp, nil
+}
+
+func (ls *LeaseServer) LeaseRevoke(ctx context.Context, rr *pb.LeaseRevokeRequest) (*pb.LeaseRevokeResponse, error) {
+	resp, err := ls.le.LeaseRevoke(ctx, rr)
+	if err != nil {
+		return nil, togRPCError(err)
+	}
+	ls.hdr.fill(resp.Header)
+	return resp, nil
+}
+
+func (ls *LeaseServer) LeaseTimeToLive(ctx context.Context, rr *pb.LeaseTimeToLiveRequest) (*pb.LeaseTimeToLiveResponse, error) {
+	resp, err := ls.le.LeaseTimeToLive(ctx, rr)
+	if err != nil && !errors.Is(err, lease.ErrLeaseNotFound) {
+		return nil, togRPCError(err)
+	}
+	if errors.Is(err, lease.ErrLeaseNotFound) {
+		resp = &pb.LeaseTimeToLiveResponse{
+			Header: &pb.ResponseHeader{},
+			ID:     rr.ID,
+			TTL:    -1,
+		}
+	}
+	ls.hdr.fill(resp.Header)
+	return resp, nil
+}
+
+func (ls *LeaseServer) LeaseLeases(ctx context.Context, rr *pb.LeaseLeasesRequest) (*pb.LeaseLeasesResponse, error) {
+	resp, err := ls.le.LeaseLeases(ctx, rr)
+	if err != nil && !errors.Is(err, lease.ErrLeaseNotFound) {
+		return nil, togRPCError(err)
+	}
+	if errors.Is(err, lease.ErrLeaseNotFound) {
+		resp = &pb.LeaseLeasesResponse{
+			Header: &pb.ResponseHeader{},
+			Leases: []*pb.LeaseStatus{},
+		}
+	}
+	ls.hdr.fill(resp.Header)
+	return resp, nil
+}
+
+func (ls *LeaseServer) LeaseKeepAlive(stream pb.Lease_LeaseKeepAliveServer) (err error) {
+	errc := make(chan error, 1)
+	go func() {
+		errc <- ls.leaseKeepAlive(stream)
+	}()
+	select {
+	case err = <-errc:
+	case <-stream.Context().Done():
+		// the only server-side cancellation is noleader for now.
+		err = stream.Context().Err()
+		if errors.Is(err, context.Canceled) {
+			err = rpctypes.ErrGRPCNoLeader
+		}
+	}
+	return err
+}
+
+func (ls *LeaseServer) leaseKeepAlive(stream pb.Lease_LeaseKeepAliveServer) error {
+	for {
+		req, err := stream.Recv()
+		if errors.Is(err, io.EOF) {
+			return nil
+		}
+		if err != nil {
+			if isClientCtxErr(stream.Context().Err(), err) {
+				ls.lg.Debug("failed to receive lease keepalive request from gRPC stream", zap.Error(err))
+			} else {
+				ls.lg.Warn("failed to receive lease keepalive request from gRPC stream", zap.Error(err))
+				streamFailures.WithLabelValues("receive", "lease-keepalive").Inc()
+			}
+			return err
+		}
+
+		// Create header before we sent out the renew request.
+		// This can make sure that the revision is strictly smaller or equal to
+		// when the keepalive happened at the local server (when the local server is the leader)
+		// or remote leader.
+		// Without this, a lease might be revoked at rev 3 but client can see the keepalive succeeded
+		// at rev 4.
+		resp := &pb.LeaseKeepAliveResponse{ID: req.ID, Header: &pb.ResponseHeader{}}
+		ls.hdr.fill(resp.Header)
+
+		ttl, err := ls.le.LeaseRenew(stream.Context(), lease.LeaseID(req.ID))
+		if errors.Is(err, lease.ErrLeaseNotFound) {
+			err = nil
+			ttl = 0
+		}
+
+		if err != nil {
+			return togRPCError(err)
+		}
+
+		resp.TTL = ttl
+		err = stream.Send(resp)
+		if err != nil {
+			if isClientCtxErr(stream.Context().Err(), err) {
+				ls.lg.Debug("failed to send lease keepalive response to gRPC stream", zap.Error(err))
+			} else {
+				ls.lg.Warn("failed to send lease keepalive response to gRPC stream", zap.Error(err))
+				streamFailures.WithLabelValues("send", "lease-keepalive").Inc()
+			}
+			return err
+		}
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/maintenance.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/maintenance.go
new file mode 100644
index 0000000..ec7de44
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/maintenance.go
@@ -0,0 +1,370 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v3rpc
+
+import (
+	"context"
+	"crypto/sha256"
+	errorspkg "errors"
+	"io"
+	"time"
+
+	"github.com/dustin/go-humanize"
+	"go.uber.org/zap"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/api/v3/v3rpc/rpctypes"
+	"go.etcd.io/etcd/api/v3/version"
+	"go.etcd.io/etcd/server/v3/config"
+	"go.etcd.io/etcd/server/v3/etcdserver"
+	"go.etcd.io/etcd/server/v3/etcdserver/apply"
+	"go.etcd.io/etcd/server/v3/etcdserver/errors"
+	serverversion "go.etcd.io/etcd/server/v3/etcdserver/version"
+	"go.etcd.io/etcd/server/v3/storage/backend"
+	"go.etcd.io/etcd/server/v3/storage/mvcc"
+	"go.etcd.io/etcd/server/v3/storage/schema"
+	"go.etcd.io/raft/v3"
+)
+
+type KVGetter interface {
+	KV() mvcc.WatchableKV
+}
+
+type BackendGetter interface {
+	Backend() backend.Backend
+}
+
+type Defrager interface {
+	Defragment() error
+}
+
+type Alarmer interface {
+	// Alarms is implemented in Server interface located in etcdserver/server.go
+	// It returns a list of alarms present in the AlarmStore
+	Alarms() []*pb.AlarmMember
+	Alarm(ctx context.Context, ar *pb.AlarmRequest) (*pb.AlarmResponse, error)
+}
+
+type Downgrader interface {
+	Downgrade(ctx context.Context, dr *pb.DowngradeRequest) (*pb.DowngradeResponse, error)
+}
+
+type LeaderTransferrer interface {
+	MoveLeader(ctx context.Context, lead, target uint64) error
+}
+
+type ClusterStatusGetter interface {
+	IsLearner() bool
+}
+
+type ConfigGetter interface {
+	Config() config.ServerConfig
+}
+
+type maintenanceServer struct {
+	lg     *zap.Logger
+	rg     apply.RaftStatusGetter
+	hasher mvcc.HashStorage
+	bg     BackendGetter
+	defrag Defrager
+	a      Alarmer
+	lt     LeaderTransferrer
+	hdr    header
+	cs     ClusterStatusGetter
+	d      Downgrader
+	vs     serverversion.Server
+	cg     ConfigGetter
+
+	healthNotifier notifier
+}
+
+func NewMaintenanceServer(s *etcdserver.EtcdServer, healthNotifier notifier) pb.MaintenanceServer {
+	srv := &maintenanceServer{
+		lg:             s.Cfg.Logger,
+		rg:             s,
+		hasher:         s.KV().HashStorage(),
+		bg:             s,
+		defrag:         s,
+		a:              s,
+		lt:             s,
+		hdr:            newHeader(s),
+		cs:             s,
+		d:              s,
+		vs:             etcdserver.NewServerVersionAdapter(s),
+		healthNotifier: healthNotifier,
+		cg:             s,
+	}
+	if srv.lg == nil {
+		srv.lg = zap.NewNop()
+	}
+	return &authMaintenanceServer{srv, &AuthAdmin{s}}
+}
+
+func (ms *maintenanceServer) Defragment(ctx context.Context, sr *pb.DefragmentRequest) (*pb.DefragmentResponse, error) {
+	ms.lg.Info("starting defragment")
+	ms.healthNotifier.defragStarted()
+	defer ms.healthNotifier.defragFinished()
+	err := ms.defrag.Defragment()
+	if err != nil {
+		ms.lg.Warn("failed to defragment", zap.Error(err))
+		return nil, togRPCError(err)
+	}
+	ms.lg.Info("finished defragment")
+	return &pb.DefragmentResponse{}, nil
+}
+
+// big enough size to hold >1 OS pages in the buffer
+const snapshotSendBufferSize = 32 * 1024
+
+func (ms *maintenanceServer) Snapshot(sr *pb.SnapshotRequest, srv pb.Maintenance_SnapshotServer) error {
+	ver := schema.ReadStorageVersion(ms.bg.Backend().ReadTx())
+	storageVersion := ""
+	if ver != nil {
+		storageVersion = ver.String()
+	}
+	snap := ms.bg.Backend().Snapshot()
+	pr, pw := io.Pipe()
+
+	defer pr.Close()
+
+	go func() {
+		snap.WriteTo(pw)
+		if err := snap.Close(); err != nil {
+			ms.lg.Warn("failed to close snapshot", zap.Error(err))
+		}
+		pw.Close()
+	}()
+
+	// record SHA digest of snapshot data
+	// used for integrity checks during snapshot restore operation
+	h := sha256.New()
+
+	sent := int64(0)
+	total := snap.Size()
+	size := humanize.Bytes(uint64(total))
+
+	start := time.Now()
+	ms.lg.Info("sending database snapshot to client",
+		zap.Int64("total-bytes", total),
+		zap.String("size", size),
+		zap.String("storage-version", storageVersion),
+	)
+	for total-sent > 0 {
+		// buffer just holds read bytes from stream
+		// response size is multiple of OS page size, fetched in boltdb
+		// e.g. 4*1024
+		// NOTE: srv.Send does not wait until the message is received by the client.
+		// Therefore the buffer can not be safely reused between Send operations
+		buf := make([]byte, snapshotSendBufferSize)
+
+		n, err := io.ReadFull(pr, buf)
+		if err != nil && !errorspkg.Is(err, io.EOF) && !errorspkg.Is(err, io.ErrUnexpectedEOF) {
+			return togRPCError(err)
+		}
+		sent += int64(n)
+
+		// if total is x * snapshotSendBufferSize. it is possible that
+		// resp.RemainingBytes == 0
+		// resp.Blob == zero byte but not nil
+		// does this make server response sent to client nil in proto
+		// and client stops receiving from snapshot stream before
+		// server sends snapshot SHA?
+		// No, the client will still receive non-nil response
+		// until server closes the stream with EOF
+		resp := &pb.SnapshotResponse{
+			RemainingBytes: uint64(total - sent),
+			Blob:           buf[:n],
+			Version:        storageVersion,
+		}
+		if err = srv.Send(resp); err != nil {
+			return togRPCError(err)
+		}
+		h.Write(buf[:n])
+	}
+
+	// send SHA digest for integrity checks
+	// during snapshot restore operation
+	sha := h.Sum(nil)
+
+	ms.lg.Info("sending database sha256 checksum to client",
+		zap.Int64("total-bytes", total),
+		zap.Int("checksum-size", len(sha)),
+	)
+	hresp := &pb.SnapshotResponse{RemainingBytes: 0, Blob: sha, Version: storageVersion}
+	if err := srv.Send(hresp); err != nil {
+		return togRPCError(err)
+	}
+
+	ms.lg.Info("successfully sent database snapshot to client",
+		zap.Int64("total-bytes", total),
+		zap.String("size", size),
+		zap.Duration("took", time.Since(start)),
+		zap.String("storage-version", storageVersion),
+	)
+	return nil
+}
+
+func (ms *maintenanceServer) Hash(ctx context.Context, r *pb.HashRequest) (*pb.HashResponse, error) {
+	h, rev, err := ms.hasher.Hash()
+	if err != nil {
+		return nil, togRPCError(err)
+	}
+	resp := &pb.HashResponse{Header: &pb.ResponseHeader{Revision: rev}, Hash: h}
+	ms.hdr.fill(resp.Header)
+	return resp, nil
+}
+
+func (ms *maintenanceServer) HashKV(ctx context.Context, r *pb.HashKVRequest) (*pb.HashKVResponse, error) {
+	h, rev, err := ms.hasher.HashByRev(r.Revision)
+	if err != nil {
+		return nil, togRPCError(err)
+	}
+
+	resp := &pb.HashKVResponse{
+		Header:          &pb.ResponseHeader{Revision: rev},
+		Hash:            h.Hash,
+		CompactRevision: h.CompactRevision,
+		HashRevision:    h.Revision,
+	}
+	ms.hdr.fill(resp.Header)
+	return resp, nil
+}
+
+func (ms *maintenanceServer) Alarm(ctx context.Context, ar *pb.AlarmRequest) (*pb.AlarmResponse, error) {
+	resp, err := ms.a.Alarm(ctx, ar)
+	if err != nil {
+		return nil, togRPCError(err)
+	}
+	if resp.Header == nil {
+		resp.Header = &pb.ResponseHeader{}
+	}
+	ms.hdr.fill(resp.Header)
+	return resp, nil
+}
+
+func (ms *maintenanceServer) Status(ctx context.Context, ar *pb.StatusRequest) (*pb.StatusResponse, error) {
+	hdr := &pb.ResponseHeader{}
+	ms.hdr.fill(hdr)
+	resp := &pb.StatusResponse{
+		Header:           hdr,
+		Version:          version.Version,
+		Leader:           uint64(ms.rg.Leader()),
+		RaftIndex:        ms.rg.CommittedIndex(),
+		RaftAppliedIndex: ms.rg.AppliedIndex(),
+		RaftTerm:         ms.rg.Term(),
+		DbSize:           ms.bg.Backend().Size(),
+		DbSizeInUse:      ms.bg.Backend().SizeInUse(),
+		IsLearner:        ms.cs.IsLearner(),
+		DbSizeQuota:      ms.cg.Config().QuotaBackendBytes,
+		DowngradeInfo:    &pb.DowngradeInfo{Enabled: false},
+	}
+	if storageVersion := ms.vs.GetStorageVersion(); storageVersion != nil {
+		resp.StorageVersion = storageVersion.String()
+	}
+	if downgradeInfo := ms.vs.GetDowngradeInfo(); downgradeInfo != nil {
+		resp.DowngradeInfo = &pb.DowngradeInfo{
+			Enabled:       downgradeInfo.Enabled,
+			TargetVersion: downgradeInfo.TargetVersion,
+		}
+	}
+	if resp.Leader == raft.None {
+		resp.Errors = append(resp.Errors, errors.ErrNoLeader.Error())
+	}
+	for _, a := range ms.a.Alarms() {
+		resp.Errors = append(resp.Errors, a.String())
+	}
+	return resp, nil
+}
+
+func (ms *maintenanceServer) MoveLeader(ctx context.Context, tr *pb.MoveLeaderRequest) (*pb.MoveLeaderResponse, error) {
+	if ms.rg.MemberID() != ms.rg.Leader() {
+		return nil, rpctypes.ErrGRPCNotLeader
+	}
+
+	if err := ms.lt.MoveLeader(ctx, uint64(ms.rg.Leader()), tr.TargetID); err != nil {
+		return nil, togRPCError(err)
+	}
+	return &pb.MoveLeaderResponse{}, nil
+}
+
+func (ms *maintenanceServer) Downgrade(ctx context.Context, r *pb.DowngradeRequest) (*pb.DowngradeResponse, error) {
+	resp, err := ms.d.Downgrade(ctx, r)
+	if err != nil {
+		return nil, togRPCError(err)
+	}
+	resp.Header = &pb.ResponseHeader{}
+	ms.hdr.fill(resp.Header)
+	return resp, nil
+}
+
+type authMaintenanceServer struct {
+	*maintenanceServer
+	*AuthAdmin
+}
+
+func (ams *authMaintenanceServer) Defragment(ctx context.Context, sr *pb.DefragmentRequest) (*pb.DefragmentResponse, error) {
+	if err := ams.isPermitted(ctx); err != nil {
+		return nil, togRPCError(err)
+	}
+
+	return ams.maintenanceServer.Defragment(ctx, sr)
+}
+
+func (ams *authMaintenanceServer) Snapshot(sr *pb.SnapshotRequest, srv pb.Maintenance_SnapshotServer) error {
+	if err := ams.isPermitted(srv.Context()); err != nil {
+		return togRPCError(err)
+	}
+
+	return ams.maintenanceServer.Snapshot(sr, srv)
+}
+
+func (ams *authMaintenanceServer) Hash(ctx context.Context, r *pb.HashRequest) (*pb.HashResponse, error) {
+	if err := ams.isPermitted(ctx); err != nil {
+		return nil, togRPCError(err)
+	}
+
+	return ams.maintenanceServer.Hash(ctx, r)
+}
+
+func (ams *authMaintenanceServer) HashKV(ctx context.Context, r *pb.HashKVRequest) (*pb.HashKVResponse, error) {
+	if err := ams.isPermitted(ctx); err != nil {
+		return nil, togRPCError(err)
+	}
+	return ams.maintenanceServer.HashKV(ctx, r)
+}
+
+func (ams *authMaintenanceServer) Status(ctx context.Context, ar *pb.StatusRequest) (*pb.StatusResponse, error) {
+	if err := ams.isPermitted(ctx); err != nil {
+		return nil, togRPCError(err)
+	}
+
+	return ams.maintenanceServer.Status(ctx, ar)
+}
+
+func (ams *authMaintenanceServer) MoveLeader(ctx context.Context, tr *pb.MoveLeaderRequest) (*pb.MoveLeaderResponse, error) {
+	if err := ams.isPermitted(ctx); err != nil {
+		return nil, togRPCError(err)
+	}
+
+	return ams.maintenanceServer.MoveLeader(ctx, tr)
+}
+
+func (ams *authMaintenanceServer) Downgrade(ctx context.Context, r *pb.DowngradeRequest) (*pb.DowngradeResponse, error) {
+	if err := ams.isPermitted(ctx); err != nil {
+		return nil, togRPCError(err)
+	}
+
+	return ams.maintenanceServer.Downgrade(ctx, r)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/member.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/member.go
new file mode 100644
index 0000000..7fd68fe
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/member.go
@@ -0,0 +1,124 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v3rpc
+
+import (
+	"context"
+	"time"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/api/v3/v3rpc/rpctypes"
+	"go.etcd.io/etcd/client/pkg/v3/types"
+	"go.etcd.io/etcd/server/v3/etcdserver"
+	"go.etcd.io/etcd/server/v3/etcdserver/api"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/membership"
+)
+
+type ClusterServer struct {
+	cluster api.Cluster
+	server  *etcdserver.EtcdServer
+}
+
+func NewClusterServer(s *etcdserver.EtcdServer) *ClusterServer {
+	return &ClusterServer{
+		cluster: s.Cluster(),
+		server:  s,
+	}
+}
+
+func (cs *ClusterServer) MemberAdd(ctx context.Context, r *pb.MemberAddRequest) (*pb.MemberAddResponse, error) {
+	urls, err := types.NewURLs(r.PeerURLs)
+	if err != nil {
+		return nil, rpctypes.ErrGRPCMemberBadURLs
+	}
+
+	now := time.Now()
+	var m *membership.Member
+	if r.IsLearner {
+		m = membership.NewMemberAsLearner("", urls, "", &now)
+	} else {
+		m = membership.NewMember("", urls, "", &now)
+	}
+	membs, merr := cs.server.AddMember(ctx, *m)
+	if merr != nil {
+		return nil, togRPCError(merr)
+	}
+
+	return &pb.MemberAddResponse{
+		Header: cs.header(),
+		Member: &pb.Member{
+			ID:        uint64(m.ID),
+			PeerURLs:  m.PeerURLs,
+			IsLearner: m.IsLearner,
+		},
+		Members: membersToProtoMembers(membs),
+	}, nil
+}
+
+func (cs *ClusterServer) MemberRemove(ctx context.Context, r *pb.MemberRemoveRequest) (*pb.MemberRemoveResponse, error) {
+	membs, err := cs.server.RemoveMember(ctx, r.ID)
+	if err != nil {
+		return nil, togRPCError(err)
+	}
+	return &pb.MemberRemoveResponse{Header: cs.header(), Members: membersToProtoMembers(membs)}, nil
+}
+
+func (cs *ClusterServer) MemberUpdate(ctx context.Context, r *pb.MemberUpdateRequest) (*pb.MemberUpdateResponse, error) {
+	m := membership.Member{
+		ID:             types.ID(r.ID),
+		RaftAttributes: membership.RaftAttributes{PeerURLs: r.PeerURLs},
+	}
+	membs, err := cs.server.UpdateMember(ctx, m)
+	if err != nil {
+		return nil, togRPCError(err)
+	}
+	return &pb.MemberUpdateResponse{Header: cs.header(), Members: membersToProtoMembers(membs)}, nil
+}
+
+func (cs *ClusterServer) MemberList(ctx context.Context, r *pb.MemberListRequest) (*pb.MemberListResponse, error) {
+	if r.Linearizable {
+		if err := cs.server.LinearizableReadNotify(ctx); err != nil {
+			return nil, togRPCError(err)
+		}
+	}
+	membs := membersToProtoMembers(cs.cluster.Members())
+	return &pb.MemberListResponse{Header: cs.header(), Members: membs}, nil
+}
+
+func (cs *ClusterServer) MemberPromote(ctx context.Context, r *pb.MemberPromoteRequest) (*pb.MemberPromoteResponse, error) {
+	membs, err := cs.server.PromoteMember(ctx, r.ID)
+	if err != nil {
+		return nil, togRPCError(err)
+	}
+	return &pb.MemberPromoteResponse{Header: cs.header(), Members: membersToProtoMembers(membs)}, nil
+}
+
+func (cs *ClusterServer) header() *pb.ResponseHeader {
+	return &pb.ResponseHeader{ClusterId: uint64(cs.cluster.ID()), MemberId: uint64(cs.server.MemberID()), RaftTerm: cs.server.Term()}
+}
+
+func membersToProtoMembers(membs []*membership.Member) []*pb.Member {
+	protoMembs := make([]*pb.Member, len(membs))
+	for i := range membs {
+		protoMembs[i] = &pb.Member{
+			Name:       membs[i].Name,
+			ID:         uint64(membs[i].ID),
+			PeerURLs:   membs[i].PeerURLs,
+			ClientURLs: membs[i].ClientURLs,
+			IsLearner:  membs[i].IsLearner,
+		}
+	}
+	return protoMembs
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/metrics.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/metrics.go
new file mode 100644
index 0000000..d79506e
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/metrics.go
@@ -0,0 +1,62 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v3rpc
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+var (
+	sentBytes = prometheus.NewCounter(prometheus.CounterOpts{
+		Namespace: "etcd",
+		Subsystem: "network",
+		Name:      "client_grpc_sent_bytes_total",
+		Help:      "The total number of bytes sent to grpc clients.",
+	})
+
+	receivedBytes = prometheus.NewCounter(prometheus.CounterOpts{
+		Namespace: "etcd",
+		Subsystem: "network",
+		Name:      "client_grpc_received_bytes_total",
+		Help:      "The total number of bytes received from grpc clients.",
+	})
+
+	streamFailures = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: "etcd",
+			Subsystem: "network",
+			Name:      "server_stream_failures_total",
+			Help:      "The total number of stream failures from the local server.",
+		},
+		[]string{"Type", "API"},
+	)
+
+	clientRequests = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: "etcd",
+			Subsystem: "server",
+			Name:      "client_requests_total",
+			Help:      "The total number of client requests per client version.",
+		},
+		[]string{"type", "client_api_version"},
+	)
+)
+
+func init() {
+	prometheus.MustRegister(sentBytes)
+	prometheus.MustRegister(receivedBytes)
+	prometheus.MustRegister(streamFailures)
+	prometheus.MustRegister(clientRequests)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/quota.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/quota.go
new file mode 100644
index 0000000..13bb83f
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/quota.go
@@ -0,0 +1,95 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v3rpc
+
+import (
+	"context"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/api/v3/v3rpc/rpctypes"
+	"go.etcd.io/etcd/client/pkg/v3/types"
+	"go.etcd.io/etcd/server/v3/etcdserver"
+	"go.etcd.io/etcd/server/v3/storage"
+)
+
+type quotaKVServer struct {
+	pb.KVServer
+	qa quotaAlarmer
+}
+
+type quotaAlarmer struct {
+	q  storage.Quota
+	a  Alarmer
+	id types.ID
+}
+
+// check whether request satisfies the quota. If there is not enough space,
+// ignore request and raise the free space alarm.
+func (qa *quotaAlarmer) check(ctx context.Context, r any) error {
+	if qa.q.Available(r) {
+		return nil
+	}
+	req := &pb.AlarmRequest{
+		MemberID: uint64(qa.id),
+		Action:   pb.AlarmRequest_ACTIVATE,
+		Alarm:    pb.AlarmType_NOSPACE,
+	}
+	qa.a.Alarm(ctx, req)
+	return rpctypes.ErrGRPCNoSpace
+}
+
+func NewQuotaKVServer(s *etcdserver.EtcdServer) pb.KVServer {
+	return &quotaKVServer{
+		NewKVServer(s),
+		quotaAlarmer{newBackendQuota(s, "kv"), s, s.MemberID()},
+	}
+}
+
+func (s *quotaKVServer) Put(ctx context.Context, r *pb.PutRequest) (*pb.PutResponse, error) {
+	if err := s.qa.check(ctx, r); err != nil {
+		return nil, err
+	}
+	return s.KVServer.Put(ctx, r)
+}
+
+func (s *quotaKVServer) Txn(ctx context.Context, r *pb.TxnRequest) (*pb.TxnResponse, error) {
+	if err := s.qa.check(ctx, r); err != nil {
+		return nil, err
+	}
+	return s.KVServer.Txn(ctx, r)
+}
+
+type quotaLeaseServer struct {
+	pb.LeaseServer
+	qa quotaAlarmer
+}
+
+func (s *quotaLeaseServer) LeaseGrant(ctx context.Context, cr *pb.LeaseGrantRequest) (*pb.LeaseGrantResponse, error) {
+	if err := s.qa.check(ctx, cr); err != nil {
+		return nil, err
+	}
+	return s.LeaseServer.LeaseGrant(ctx, cr)
+}
+
+func NewQuotaLeaseServer(s *etcdserver.EtcdServer) pb.LeaseServer {
+	return &quotaLeaseServer{
+		NewLeaseServer(s),
+		quotaAlarmer{newBackendQuota(s, "lease"), s, s.MemberID()},
+	}
+}
+
+func newBackendQuota(s *etcdserver.EtcdServer, name string) storage.Quota {
+	return storage.NewBackendQuota(s.Logger(), s.Cfg.QuotaBackendBytes, s.Backend(), name)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/util.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/util.go
new file mode 100644
index 0000000..2354b0c
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/util.go
@@ -0,0 +1,151 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v3rpc
+
+import (
+	"context"
+	errorspkg "errors"
+	"strings"
+
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/api/v3/v3rpc/rpctypes"
+	"go.etcd.io/etcd/server/v3/auth"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/membership"
+	"go.etcd.io/etcd/server/v3/etcdserver/errors"
+	"go.etcd.io/etcd/server/v3/etcdserver/version"
+	"go.etcd.io/etcd/server/v3/lease"
+	"go.etcd.io/etcd/server/v3/storage/mvcc"
+)
+
+var toGRPCErrorMap = map[error]error{
+	membership.ErrIDRemoved:           rpctypes.ErrGRPCMemberNotFound,
+	membership.ErrIDNotFound:          rpctypes.ErrGRPCMemberNotFound,
+	membership.ErrIDExists:            rpctypes.ErrGRPCMemberExist,
+	membership.ErrPeerURLexists:       rpctypes.ErrGRPCPeerURLExist,
+	membership.ErrMemberNotLearner:    rpctypes.ErrGRPCMemberNotLearner,
+	membership.ErrTooManyLearners:     rpctypes.ErrGRPCTooManyLearners,
+	errors.ErrNotEnoughStartedMembers: rpctypes.ErrMemberNotEnoughStarted,
+	errors.ErrLearnerNotReady:         rpctypes.ErrGRPCLearnerNotReady,
+
+	mvcc.ErrCompacted:         rpctypes.ErrGRPCCompacted,
+	mvcc.ErrFutureRev:         rpctypes.ErrGRPCFutureRev,
+	errors.ErrRequestTooLarge: rpctypes.ErrGRPCRequestTooLarge,
+	errors.ErrNoSpace:         rpctypes.ErrGRPCNoSpace,
+	errors.ErrTooManyRequests: rpctypes.ErrTooManyRequests,
+
+	errors.ErrNoLeader:                   rpctypes.ErrGRPCNoLeader,
+	errors.ErrNotLeader:                  rpctypes.ErrGRPCNotLeader,
+	errors.ErrLeaderChanged:              rpctypes.ErrGRPCLeaderChanged,
+	errors.ErrStopped:                    rpctypes.ErrGRPCStopped,
+	errors.ErrTimeout:                    rpctypes.ErrGRPCTimeout,
+	errors.ErrTimeoutDueToLeaderFail:     rpctypes.ErrGRPCTimeoutDueToLeaderFail,
+	errors.ErrTimeoutDueToConnectionLost: rpctypes.ErrGRPCTimeoutDueToConnectionLost,
+	errors.ErrTimeoutWaitAppliedIndex:    rpctypes.ErrGRPCTimeoutWaitAppliedIndex,
+	errors.ErrUnhealthy:                  rpctypes.ErrGRPCUnhealthy,
+	errors.ErrKeyNotFound:                rpctypes.ErrGRPCKeyNotFound,
+	errors.ErrCorrupt:                    rpctypes.ErrGRPCCorrupt,
+	errors.ErrBadLeaderTransferee:        rpctypes.ErrGRPCBadLeaderTransferee,
+
+	errors.ErrClusterVersionUnavailable:      rpctypes.ErrGRPCClusterVersionUnavailable,
+	errors.ErrWrongDowngradeVersionFormat:    rpctypes.ErrGRPCWrongDowngradeVersionFormat,
+	version.ErrInvalidDowngradeTargetVersion: rpctypes.ErrGRPCInvalidDowngradeTargetVersion,
+	version.ErrDowngradeInProcess:            rpctypes.ErrGRPCDowngradeInProcess,
+	version.ErrNoInflightDowngrade:           rpctypes.ErrGRPCNoInflightDowngrade,
+
+	lease.ErrLeaseNotFound:    rpctypes.ErrGRPCLeaseNotFound,
+	lease.ErrLeaseExists:      rpctypes.ErrGRPCLeaseExist,
+	lease.ErrLeaseTTLTooLarge: rpctypes.ErrGRPCLeaseTTLTooLarge,
+
+	auth.ErrRootUserNotExist:     rpctypes.ErrGRPCRootUserNotExist,
+	auth.ErrRootRoleNotExist:     rpctypes.ErrGRPCRootRoleNotExist,
+	auth.ErrUserAlreadyExist:     rpctypes.ErrGRPCUserAlreadyExist,
+	auth.ErrUserEmpty:            rpctypes.ErrGRPCUserEmpty,
+	auth.ErrUserNotFound:         rpctypes.ErrGRPCUserNotFound,
+	auth.ErrRoleAlreadyExist:     rpctypes.ErrGRPCRoleAlreadyExist,
+	auth.ErrRoleNotFound:         rpctypes.ErrGRPCRoleNotFound,
+	auth.ErrRoleEmpty:            rpctypes.ErrGRPCRoleEmpty,
+	auth.ErrAuthFailed:           rpctypes.ErrGRPCAuthFailed,
+	auth.ErrPermissionNotGiven:   rpctypes.ErrGRPCPermissionNotGiven,
+	auth.ErrPermissionDenied:     rpctypes.ErrGRPCPermissionDenied,
+	auth.ErrRoleNotGranted:       rpctypes.ErrGRPCRoleNotGranted,
+	auth.ErrPermissionNotGranted: rpctypes.ErrGRPCPermissionNotGranted,
+	auth.ErrAuthNotEnabled:       rpctypes.ErrGRPCAuthNotEnabled,
+	auth.ErrInvalidAuthToken:     rpctypes.ErrGRPCInvalidAuthToken,
+	auth.ErrInvalidAuthMgmt:      rpctypes.ErrGRPCInvalidAuthMgmt,
+	auth.ErrAuthOldRevision:      rpctypes.ErrGRPCAuthOldRevision,
+
+	// In sync with status.FromContextError
+	context.Canceled:         rpctypes.ErrGRPCCanceled,
+	context.DeadlineExceeded: rpctypes.ErrGRPCDeadlineExceeded,
+}
+
+func togRPCError(err error) error {
+	// let gRPC server convert to codes.Canceled, codes.DeadlineExceeded
+	if errorspkg.Is(err, context.Canceled) || errorspkg.Is(err, context.DeadlineExceeded) {
+		return err
+	}
+	grpcErr, ok := toGRPCErrorMap[err]
+	if !ok {
+		return status.Error(codes.Unknown, err.Error())
+	}
+	return grpcErr
+}
+
+func isClientCtxErr(ctxErr error, err error) bool {
+	if ctxErr != nil {
+		return true
+	}
+
+	ev, ok := status.FromError(err)
+	if !ok {
+		return false
+	}
+
+	switch ev.Code() {
+	case codes.Canceled, codes.DeadlineExceeded:
+		// client-side context cancel or deadline exceeded
+		// "rpc error: code = Canceled desc = context canceled"
+		// "rpc error: code = DeadlineExceeded desc = context deadline exceeded"
+		return true
+	case codes.Unavailable:
+		msg := ev.Message()
+		// client-side context cancel or deadline exceeded with TLS ("http2.errClientDisconnected")
+		// "rpc error: code = Unavailable desc = client disconnected"
+		if msg == "client disconnected" {
+			return true
+		}
+		// "grpc/transport.ClientTransport.CloseStream" on canceled streams
+		// "rpc error: code = Unavailable desc = stream error: stream ID 21; CANCEL")
+		if strings.HasPrefix(msg, "stream error: ") && strings.HasSuffix(msg, "; CANCEL") {
+			return true
+		}
+	}
+	return false
+}
+
+// in v3.4, learner is allowed to serve serializable read and endpoint status
+func isRPCSupportedForLearner(req any) bool {
+	switch r := req.(type) {
+	case *pb.StatusRequest:
+		return true
+	case *pb.RangeRequest:
+		return r.Serializable
+	default:
+		return false
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/watch.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/watch.go
new file mode 100644
index 0000000..d4a5bc3
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/api/v3rpc/watch.go
@@ -0,0 +1,616 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v3rpc
+
+import (
+	"context"
+	"errors"
+	"io"
+	"math/rand"
+	"sync"
+	"time"
+
+	"go.uber.org/zap"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/api/v3/mvccpb"
+	"go.etcd.io/etcd/api/v3/v3rpc/rpctypes"
+	"go.etcd.io/etcd/client/pkg/v3/verify"
+	clientv3 "go.etcd.io/etcd/client/v3"
+	"go.etcd.io/etcd/server/v3/auth"
+	"go.etcd.io/etcd/server/v3/etcdserver"
+	"go.etcd.io/etcd/server/v3/etcdserver/apply"
+	"go.etcd.io/etcd/server/v3/storage/mvcc"
+)
+
+const minWatchProgressInterval = 100 * time.Millisecond
+
+type watchServer struct {
+	lg *zap.Logger
+
+	clusterID int64
+	memberID  int64
+
+	maxRequestBytes uint
+
+	sg        apply.RaftStatusGetter
+	watchable mvcc.WatchableKV
+	ag        AuthGetter
+}
+
+// NewWatchServer returns a new watch server.
+func NewWatchServer(s *etcdserver.EtcdServer) pb.WatchServer {
+	srv := &watchServer{
+		lg: s.Cfg.Logger,
+
+		clusterID: int64(s.Cluster().ID()),
+		memberID:  int64(s.MemberID()),
+
+		maxRequestBytes: s.Cfg.MaxRequestBytesWithOverhead(),
+
+		sg:        s,
+		watchable: s.Watchable(),
+		ag:        s,
+	}
+	if srv.lg == nil {
+		srv.lg = zap.NewNop()
+	}
+	if s.Cfg.WatchProgressNotifyInterval > 0 {
+		if s.Cfg.WatchProgressNotifyInterval < minWatchProgressInterval {
+			srv.lg.Warn(
+				"adjusting watch progress notify interval to minimum period",
+				zap.Duration("min-watch-progress-notify-interval", minWatchProgressInterval),
+			)
+			s.Cfg.WatchProgressNotifyInterval = minWatchProgressInterval
+		}
+		SetProgressReportInterval(s.Cfg.WatchProgressNotifyInterval)
+	}
+	return srv
+}
+
+var (
+	// External test can read this with GetProgressReportInterval()
+	// and change this to a small value to finish fast with
+	// SetProgressReportInterval().
+	progressReportInterval   = 10 * time.Minute
+	progressReportIntervalMu sync.RWMutex
+)
+
+// GetProgressReportInterval returns the current progress report interval (for testing).
+func GetProgressReportInterval() time.Duration {
+	progressReportIntervalMu.RLock()
+	interval := progressReportInterval
+	progressReportIntervalMu.RUnlock()
+
+	// add rand(1/10*progressReportInterval) as jitter so that etcdserver will not
+	// send progress notifications to watchers around the same time even when watchers
+	// are created around the same time (which is common when a client restarts itself).
+	jitter := time.Duration(rand.Int63n(int64(interval) / 10))
+
+	return interval + jitter
+}
+
+// SetProgressReportInterval updates the current progress report interval (for testing).
+func SetProgressReportInterval(newTimeout time.Duration) {
+	progressReportIntervalMu.Lock()
+	progressReportInterval = newTimeout
+	progressReportIntervalMu.Unlock()
+}
+
+// We send ctrl response inside the read loop. We do not want
+// send to block read, but we still want ctrl response we sent to
+// be serialized. Thus we use a buffered chan to solve the problem.
+// A small buffer should be OK for most cases, since we expect the
+// ctrl requests are infrequent.
+const ctrlStreamBufLen = 16
+
+// serverWatchStream is an etcd server side stream. It receives requests
+// from client side gRPC stream. It receives watch events from mvcc.WatchStream,
+// and creates responses that forwarded to gRPC stream.
+// It also forwards control message like watch created and canceled.
+type serverWatchStream struct {
+	lg *zap.Logger
+
+	clusterID int64
+	memberID  int64
+
+	maxRequestBytes uint
+
+	sg        apply.RaftStatusGetter
+	watchable mvcc.WatchableKV
+	ag        AuthGetter
+
+	gRPCStream  pb.Watch_WatchServer
+	watchStream mvcc.WatchStream
+	ctrlStream  chan *pb.WatchResponse
+
+	// mu protects progress, prevKV, fragment
+	mu sync.RWMutex
+	// tracks the watchID that stream might need to send progress to
+	// TODO: combine progress and prevKV into a single struct?
+	progress map[mvcc.WatchID]bool
+	// record watch IDs that need return previous key-value pair
+	prevKV map[mvcc.WatchID]bool
+	// records fragmented watch IDs
+	fragment map[mvcc.WatchID]bool
+
+	// closec indicates the stream is closed.
+	closec chan struct{}
+
+	// wg waits for the send loop to complete
+	wg sync.WaitGroup
+}
+
+func (ws *watchServer) Watch(stream pb.Watch_WatchServer) (err error) {
+	sws := serverWatchStream{
+		lg: ws.lg,
+
+		clusterID: ws.clusterID,
+		memberID:  ws.memberID,
+
+		maxRequestBytes: ws.maxRequestBytes,
+
+		sg:        ws.sg,
+		watchable: ws.watchable,
+		ag:        ws.ag,
+
+		gRPCStream:  stream,
+		watchStream: ws.watchable.NewWatchStream(),
+		// chan for sending control response like watcher created and canceled.
+		ctrlStream: make(chan *pb.WatchResponse, ctrlStreamBufLen),
+
+		progress: make(map[mvcc.WatchID]bool),
+		prevKV:   make(map[mvcc.WatchID]bool),
+		fragment: make(map[mvcc.WatchID]bool),
+
+		closec: make(chan struct{}),
+	}
+
+	sws.wg.Add(1)
+	go func() {
+		sws.sendLoop()
+		sws.wg.Done()
+	}()
+
+	errc := make(chan error, 1)
+	// Ideally recvLoop would also use sws.wg to signal its completion
+	// but when stream.Context().Done() is closed, the stream's recv
+	// may continue to block since it uses a different context, leading to
+	// deadlock when calling sws.close().
+	go func() {
+		if rerr := sws.recvLoop(); rerr != nil {
+			if isClientCtxErr(stream.Context().Err(), rerr) {
+				sws.lg.Debug("failed to receive watch request from gRPC stream", zap.Error(rerr))
+			} else {
+				sws.lg.Warn("failed to receive watch request from gRPC stream", zap.Error(rerr))
+				streamFailures.WithLabelValues("receive", "watch").Inc()
+			}
+			errc <- rerr
+		}
+	}()
+
+	// TODO: There's a race here. When a stream  is closed (e.g. due to a cancellation),
+	// the underlying error (e.g. a gRPC stream error) may be returned and handled
+	// through errc if the recv goroutine finishes before the send goroutine.
+	// When the recv goroutine wins, the stream error is retained. When recv loses
+	// the race, the underlying error is lost (unless the root error is propagated
+	// through Context.Err() which is not always the case (as callers have to decide
+	// to implement a custom context to do so). The stdlib context package builtins
+	// may be insufficient to carry semantically useful errors around and should be
+	// revisited.
+	select {
+	case err = <-errc:
+		if errors.Is(err, context.Canceled) {
+			err = rpctypes.ErrGRPCWatchCanceled
+		}
+		close(sws.ctrlStream)
+	case <-stream.Context().Done():
+		err = stream.Context().Err()
+		if errors.Is(err, context.Canceled) {
+			err = rpctypes.ErrGRPCWatchCanceled
+		}
+	}
+
+	sws.close()
+	return err
+}
+
+func (sws *serverWatchStream) isWatchPermitted(wcr *pb.WatchCreateRequest) error {
+	authInfo, err := sws.ag.AuthInfoFromCtx(sws.gRPCStream.Context())
+	if err != nil {
+		return err
+	}
+	if authInfo == nil {
+		// if auth is enabled, IsRangePermitted() can cause an error
+		authInfo = &auth.AuthInfo{}
+	}
+	return sws.ag.AuthStore().IsRangePermitted(authInfo, wcr.Key, wcr.RangeEnd)
+}
+
+func (sws *serverWatchStream) recvLoop() error {
+	for {
+		req, err := sws.gRPCStream.Recv()
+		if errors.Is(err, io.EOF) {
+			return nil
+		}
+		if err != nil {
+			return err
+		}
+
+		switch uv := req.RequestUnion.(type) {
+		case *pb.WatchRequest_CreateRequest:
+			if uv.CreateRequest == nil {
+				break
+			}
+
+			creq := uv.CreateRequest
+			if len(creq.Key) == 0 {
+				// \x00 is the smallest key
+				creq.Key = []byte{0}
+			}
+			if len(creq.RangeEnd) == 0 {
+				// force nil since watchstream.Watch distinguishes
+				// between nil and []byte{} for single key / >=
+				creq.RangeEnd = nil
+			}
+			if len(creq.RangeEnd) == 1 && creq.RangeEnd[0] == 0 {
+				// support  >= key queries
+				creq.RangeEnd = []byte{}
+			}
+
+			err := sws.isWatchPermitted(creq)
+			if err != nil {
+				var cancelReason string
+				switch {
+				case errors.Is(err, auth.ErrInvalidAuthToken):
+					cancelReason = rpctypes.ErrGRPCInvalidAuthToken.Error()
+				case errors.Is(err, auth.ErrAuthOldRevision):
+					cancelReason = rpctypes.ErrGRPCAuthOldRevision.Error()
+				case errors.Is(err, auth.ErrUserEmpty):
+					cancelReason = rpctypes.ErrGRPCUserEmpty.Error()
+				default:
+					if !errors.Is(err, auth.ErrPermissionDenied) {
+						sws.lg.Error("unexpected error code", zap.Error(err))
+					}
+					cancelReason = rpctypes.ErrGRPCPermissionDenied.Error()
+				}
+
+				wr := &pb.WatchResponse{
+					Header:       sws.newResponseHeader(sws.watchStream.Rev()),
+					WatchId:      clientv3.InvalidWatchID,
+					Canceled:     true,
+					Created:      true,
+					CancelReason: cancelReason,
+				}
+
+				select {
+				case sws.ctrlStream <- wr:
+					continue
+				case <-sws.closec:
+					return nil
+				}
+			}
+
+			filters := FiltersFromRequest(creq)
+
+			id, err := sws.watchStream.Watch(mvcc.WatchID(creq.WatchId), creq.Key, creq.RangeEnd, creq.StartRevision, filters...)
+			if err == nil {
+				sws.mu.Lock()
+				if creq.ProgressNotify {
+					sws.progress[id] = true
+				}
+				if creq.PrevKv {
+					sws.prevKV[id] = true
+				}
+				if creq.Fragment {
+					sws.fragment[id] = true
+				}
+				sws.mu.Unlock()
+			} else {
+				id = clientv3.InvalidWatchID
+			}
+
+			wr := &pb.WatchResponse{
+				Header:   sws.newResponseHeader(sws.watchStream.Rev()),
+				WatchId:  int64(id),
+				Created:  true,
+				Canceled: err != nil,
+			}
+			if err != nil {
+				wr.CancelReason = err.Error()
+			}
+			select {
+			case sws.ctrlStream <- wr:
+			case <-sws.closec:
+				return nil
+			}
+
+		case *pb.WatchRequest_CancelRequest:
+			if uv.CancelRequest != nil {
+				id := uv.CancelRequest.WatchId
+				err := sws.watchStream.Cancel(mvcc.WatchID(id))
+				if err == nil {
+					wr := &pb.WatchResponse{
+						Header:   sws.newResponseHeader(sws.watchStream.Rev()),
+						WatchId:  id,
+						Canceled: true,
+					}
+					select {
+					case sws.ctrlStream <- wr:
+					case <-sws.closec:
+						return nil
+					}
+
+					sws.mu.Lock()
+					delete(sws.progress, mvcc.WatchID(id))
+					delete(sws.prevKV, mvcc.WatchID(id))
+					delete(sws.fragment, mvcc.WatchID(id))
+					sws.mu.Unlock()
+				}
+			}
+		case *pb.WatchRequest_ProgressRequest:
+			if uv.ProgressRequest != nil {
+				sws.mu.Lock()
+				sws.watchStream.RequestProgressAll()
+				sws.mu.Unlock()
+			}
+		default:
+			// we probably should not shutdown the entire stream when
+			// receive an invalid command.
+			// so just do nothing instead.
+			sws.lg.Sugar().Infof("invalid watch request type %T received in gRPC stream", uv)
+			continue
+		}
+	}
+}
+
+func (sws *serverWatchStream) sendLoop() {
+	// watch ids that are currently active
+	ids := make(map[mvcc.WatchID]struct{})
+	// watch responses pending on a watch id creation message
+	pending := make(map[mvcc.WatchID][]*pb.WatchResponse)
+
+	interval := GetProgressReportInterval()
+	progressTicker := time.NewTicker(interval)
+
+	defer func() {
+		progressTicker.Stop()
+		// drain the chan to clean up pending events
+		for ws := range sws.watchStream.Chan() {
+			mvcc.ReportEventReceived(len(ws.Events))
+		}
+		for _, wrs := range pending {
+			for _, ws := range wrs {
+				mvcc.ReportEventReceived(len(ws.Events))
+			}
+		}
+	}()
+
+	for {
+		select {
+		case wresp, ok := <-sws.watchStream.Chan():
+			if !ok {
+				return
+			}
+
+			// TODO: evs is []mvccpb.Event type
+			// either return []*mvccpb.Event from the mvcc package
+			// or define protocol buffer with []mvccpb.Event.
+			evs := wresp.Events
+			events := make([]*mvccpb.Event, len(evs))
+			sws.mu.RLock()
+			needPrevKV := sws.prevKV[wresp.WatchID]
+			sws.mu.RUnlock()
+			for i := range evs {
+				events[i] = &evs[i]
+				if needPrevKV && !IsCreateEvent(evs[i]) {
+					opt := mvcc.RangeOptions{Rev: evs[i].Kv.ModRevision - 1}
+					r, err := sws.watchable.Range(context.TODO(), evs[i].Kv.Key, nil, opt)
+					if err == nil && len(r.KVs) != 0 {
+						events[i].PrevKv = &(r.KVs[0])
+					}
+				}
+			}
+
+			canceled := wresp.CompactRevision != 0
+			wr := &pb.WatchResponse{
+				Header:          sws.newResponseHeader(wresp.Revision),
+				WatchId:         int64(wresp.WatchID),
+				Events:          events,
+				CompactRevision: wresp.CompactRevision,
+				Canceled:        canceled,
+			}
+
+			// Progress notifications can have WatchID -1
+			// if they announce on behalf of multiple watchers
+			if wresp.WatchID != clientv3.InvalidWatchID {
+				if _, okID := ids[wresp.WatchID]; !okID {
+					// buffer if id not yet announced
+					wrs := append(pending[wresp.WatchID], wr)
+					pending[wresp.WatchID] = wrs
+					continue
+				}
+			}
+
+			mvcc.ReportEventReceived(len(evs))
+
+			sws.mu.RLock()
+			fragmented, ok := sws.fragment[wresp.WatchID]
+			sws.mu.RUnlock()
+
+			var serr error
+			// gofail: var beforeSendWatchResponse struct{}
+			if !fragmented && !ok {
+				serr = sws.gRPCStream.Send(wr)
+			} else {
+				serr = sendFragments(wr, sws.maxRequestBytes, sws.gRPCStream.Send)
+			}
+
+			if serr != nil {
+				if isClientCtxErr(sws.gRPCStream.Context().Err(), serr) {
+					sws.lg.Debug("failed to send watch response to gRPC stream", zap.Error(serr))
+				} else {
+					sws.lg.Warn("failed to send watch response to gRPC stream", zap.Error(serr))
+					streamFailures.WithLabelValues("send", "watch").Inc()
+				}
+				return
+			}
+
+			sws.mu.Lock()
+			if len(evs) > 0 && sws.progress[wresp.WatchID] {
+				// elide next progress update if sent a key update
+				sws.progress[wresp.WatchID] = false
+			}
+			sws.mu.Unlock()
+
+		case c, ok := <-sws.ctrlStream:
+			if !ok {
+				return
+			}
+
+			if err := sws.gRPCStream.Send(c); err != nil {
+				if isClientCtxErr(sws.gRPCStream.Context().Err(), err) {
+					sws.lg.Debug("failed to send watch control response to gRPC stream", zap.Error(err))
+				} else {
+					sws.lg.Warn("failed to send watch control response to gRPC stream", zap.Error(err))
+					streamFailures.WithLabelValues("send", "watch").Inc()
+				}
+				return
+			}
+
+			// track id creation
+			wid := mvcc.WatchID(c.WatchId)
+
+			verify.Assert(!(c.Canceled && c.Created) || wid == clientv3.InvalidWatchID, "unexpected watchId: %d, wanted: %d, since both 'Canceled' and 'Created' are true", wid, clientv3.InvalidWatchID)
+
+			if c.Canceled && wid != clientv3.InvalidWatchID {
+				delete(ids, wid)
+				continue
+			}
+			if c.Created {
+				// flush buffered events
+				ids[wid] = struct{}{}
+				for _, v := range pending[wid] {
+					mvcc.ReportEventReceived(len(v.Events))
+					if err := sws.gRPCStream.Send(v); err != nil {
+						if isClientCtxErr(sws.gRPCStream.Context().Err(), err) {
+							sws.lg.Debug("failed to send pending watch response to gRPC stream", zap.Error(err))
+						} else {
+							sws.lg.Warn("failed to send pending watch response to gRPC stream", zap.Error(err))
+							streamFailures.WithLabelValues("send", "watch").Inc()
+						}
+						return
+					}
+				}
+				delete(pending, wid)
+			}
+
+		case <-progressTicker.C:
+			sws.mu.Lock()
+			for id, ok := range sws.progress {
+				if ok {
+					sws.watchStream.RequestProgress(id)
+				}
+				sws.progress[id] = true
+			}
+			sws.mu.Unlock()
+
+		case <-sws.closec:
+			return
+		}
+	}
+}
+
+func IsCreateEvent(e mvccpb.Event) bool {
+	return e.Type == mvccpb.PUT && e.Kv.CreateRevision == e.Kv.ModRevision
+}
+
+func sendFragments(
+	wr *pb.WatchResponse,
+	maxRequestBytes uint,
+	sendFunc func(*pb.WatchResponse) error,
+) error {
+	// no need to fragment if total request size is smaller
+	// than max request limit or response contains only one event
+	if uint(wr.Size()) < maxRequestBytes || len(wr.Events) < 2 {
+		return sendFunc(wr)
+	}
+
+	ow := *wr
+	ow.Events = make([]*mvccpb.Event, 0)
+	ow.Fragment = true
+
+	var idx int
+	for {
+		cur := ow
+		for _, ev := range wr.Events[idx:] {
+			cur.Events = append(cur.Events, ev)
+			if len(cur.Events) > 1 && uint(cur.Size()) >= maxRequestBytes {
+				cur.Events = cur.Events[:len(cur.Events)-1]
+				break
+			}
+			idx++
+		}
+		if idx == len(wr.Events) {
+			// last response has no more fragment
+			cur.Fragment = false
+		}
+		if err := sendFunc(&cur); err != nil {
+			return err
+		}
+		if !cur.Fragment {
+			break
+		}
+	}
+	return nil
+}
+
+func (sws *serverWatchStream) close() {
+	sws.watchStream.Close()
+	close(sws.closec)
+	sws.wg.Wait()
+}
+
+func (sws *serverWatchStream) newResponseHeader(rev int64) *pb.ResponseHeader {
+	return &pb.ResponseHeader{
+		ClusterId: uint64(sws.clusterID),
+		MemberId:  uint64(sws.memberID),
+		Revision:  rev,
+		RaftTerm:  sws.sg.Term(),
+	}
+}
+
+func filterNoDelete(e mvccpb.Event) bool {
+	return e.Type == mvccpb.DELETE
+}
+
+func filterNoPut(e mvccpb.Event) bool {
+	return e.Type == mvccpb.PUT
+}
+
+// FiltersFromRequest returns "mvcc.FilterFunc" from a given watch create request.
+func FiltersFromRequest(creq *pb.WatchCreateRequest) []mvcc.FilterFunc {
+	filters := make([]mvcc.FilterFunc, 0, len(creq.Filters))
+	for _, ft := range creq.Filters {
+		switch ft {
+		case pb.WatchCreateRequest_NOPUT:
+			filters = append(filters, filterNoPut)
+		case pb.WatchCreateRequest_NODELETE:
+			filters = append(filters, filterNoDelete)
+		default:
+		}
+	}
+	return filters
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/apply/apply.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/apply/apply.go
new file mode 100644
index 0000000..e45d53e
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/apply/apply.go
@@ -0,0 +1,493 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package apply
+
+import (
+	"context"
+
+	"github.com/coreos/go-semver/semver"
+	"github.com/gogo/protobuf/proto"
+	"go.uber.org/zap"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/api/v3/membershippb"
+	"go.etcd.io/etcd/client/pkg/v3/types"
+	"go.etcd.io/etcd/pkg/v3/traceutil"
+	"go.etcd.io/etcd/server/v3/auth"
+	"go.etcd.io/etcd/server/v3/etcdserver/api"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/membership"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v3alarm"
+	"go.etcd.io/etcd/server/v3/etcdserver/cindex"
+	"go.etcd.io/etcd/server/v3/etcdserver/errors"
+	mvcctxn "go.etcd.io/etcd/server/v3/etcdserver/txn"
+	"go.etcd.io/etcd/server/v3/etcdserver/version"
+	"go.etcd.io/etcd/server/v3/lease"
+	serverstorage "go.etcd.io/etcd/server/v3/storage"
+	"go.etcd.io/etcd/server/v3/storage/backend"
+	"go.etcd.io/etcd/server/v3/storage/mvcc"
+)
+
+const (
+	v3Version = "v3"
+)
+
+// RaftStatusGetter represents etcd server and Raft progress.
+type RaftStatusGetter interface {
+	MemberID() types.ID
+	Leader() types.ID
+	CommittedIndex() uint64
+	AppliedIndex() uint64
+	Term() uint64
+}
+
+type Result struct {
+	Resp proto.Message
+	Err  error
+	// Physc signals the physical effect of the request has completed in addition
+	// to being logically reflected by the node. Currently, only used for
+	// Compaction requests.
+	Physc <-chan struct{}
+	Trace *traceutil.Trace
+}
+
+type applyFunc func(r *pb.InternalRaftRequest) *Result
+
+// applierV3 is the interface for processing V3 raft messages
+type applierV3 interface {
+	// Apply executes the generic portion of application logic for the current applier, but
+	// delegates the actual execution to the applyFunc method.
+	Apply(r *pb.InternalRaftRequest, applyFunc applyFunc) *Result
+
+	Put(p *pb.PutRequest) (*pb.PutResponse, *traceutil.Trace, error)
+	Range(r *pb.RangeRequest) (*pb.RangeResponse, *traceutil.Trace, error)
+	DeleteRange(dr *pb.DeleteRangeRequest) (*pb.DeleteRangeResponse, *traceutil.Trace, error)
+	Txn(rt *pb.TxnRequest) (*pb.TxnResponse, *traceutil.Trace, error)
+	Compaction(compaction *pb.CompactionRequest) (*pb.CompactionResponse, <-chan struct{}, *traceutil.Trace, error)
+
+	LeaseGrant(lc *pb.LeaseGrantRequest) (*pb.LeaseGrantResponse, error)
+	LeaseRevoke(lc *pb.LeaseRevokeRequest) (*pb.LeaseRevokeResponse, error)
+
+	LeaseCheckpoint(lc *pb.LeaseCheckpointRequest) (*pb.LeaseCheckpointResponse, error)
+
+	Alarm(*pb.AlarmRequest) (*pb.AlarmResponse, error)
+
+	Authenticate(r *pb.InternalAuthenticateRequest) (*pb.AuthenticateResponse, error)
+
+	AuthEnable() (*pb.AuthEnableResponse, error)
+	AuthDisable() (*pb.AuthDisableResponse, error)
+	AuthStatus() (*pb.AuthStatusResponse, error)
+
+	UserAdd(ua *pb.AuthUserAddRequest) (*pb.AuthUserAddResponse, error)
+	UserDelete(ua *pb.AuthUserDeleteRequest) (*pb.AuthUserDeleteResponse, error)
+	UserChangePassword(ua *pb.AuthUserChangePasswordRequest) (*pb.AuthUserChangePasswordResponse, error)
+	UserGrantRole(ua *pb.AuthUserGrantRoleRequest) (*pb.AuthUserGrantRoleResponse, error)
+	UserGet(ua *pb.AuthUserGetRequest) (*pb.AuthUserGetResponse, error)
+	UserRevokeRole(ua *pb.AuthUserRevokeRoleRequest) (*pb.AuthUserRevokeRoleResponse, error)
+	RoleAdd(ua *pb.AuthRoleAddRequest) (*pb.AuthRoleAddResponse, error)
+	RoleGrantPermission(ua *pb.AuthRoleGrantPermissionRequest) (*pb.AuthRoleGrantPermissionResponse, error)
+	RoleGet(ua *pb.AuthRoleGetRequest) (*pb.AuthRoleGetResponse, error)
+	RoleRevokePermission(ua *pb.AuthRoleRevokePermissionRequest) (*pb.AuthRoleRevokePermissionResponse, error)
+	RoleDelete(ua *pb.AuthRoleDeleteRequest) (*pb.AuthRoleDeleteResponse, error)
+	UserList(ua *pb.AuthUserListRequest) (*pb.AuthUserListResponse, error)
+	RoleList(ua *pb.AuthRoleListRequest) (*pb.AuthRoleListResponse, error)
+}
+
+type SnapshotServer interface {
+	ForceSnapshot()
+}
+
+type applierV3backend struct {
+	lg              *zap.Logger
+	kv              mvcc.KV
+	alarmStore      *v3alarm.AlarmStore
+	authStore       auth.AuthStore
+	lessor          lease.Lessor
+	cluster         *membership.RaftCluster
+	raftStatus      RaftStatusGetter
+	snapshotServer  SnapshotServer
+	consistentIndex cindex.ConsistentIndexer
+
+	txnModeWriteWithSharedBuffer bool
+}
+
+func newApplierV3Backend(
+	lg *zap.Logger,
+	kv mvcc.KV,
+	alarmStore *v3alarm.AlarmStore,
+	authStore auth.AuthStore,
+	lessor lease.Lessor,
+	cluster *membership.RaftCluster,
+	raftStatus RaftStatusGetter,
+	snapshotServer SnapshotServer,
+	consistentIndex cindex.ConsistentIndexer,
+	txnModeWriteWithSharedBuffer bool,
+) applierV3 {
+	return &applierV3backend{
+		lg:                           lg,
+		kv:                           kv,
+		alarmStore:                   alarmStore,
+		authStore:                    authStore,
+		lessor:                       lessor,
+		cluster:                      cluster,
+		raftStatus:                   raftStatus,
+		snapshotServer:               snapshotServer,
+		consistentIndex:              consistentIndex,
+		txnModeWriteWithSharedBuffer: txnModeWriteWithSharedBuffer,
+	}
+}
+
+func (a *applierV3backend) Apply(r *pb.InternalRaftRequest, applyFunc applyFunc) *Result {
+	return applyFunc(r)
+}
+
+func (a *applierV3backend) Put(p *pb.PutRequest) (resp *pb.PutResponse, trace *traceutil.Trace, err error) {
+	return mvcctxn.Put(context.TODO(), a.lg, a.lessor, a.kv, p)
+}
+
+func (a *applierV3backend) DeleteRange(dr *pb.DeleteRangeRequest) (*pb.DeleteRangeResponse, *traceutil.Trace, error) {
+	return mvcctxn.DeleteRange(context.TODO(), a.lg, a.kv, dr)
+}
+
+func (a *applierV3backend) Range(r *pb.RangeRequest) (*pb.RangeResponse, *traceutil.Trace, error) {
+	return mvcctxn.Range(context.TODO(), a.lg, a.kv, r)
+}
+
+func (a *applierV3backend) Txn(rt *pb.TxnRequest) (*pb.TxnResponse, *traceutil.Trace, error) {
+	return mvcctxn.Txn(context.TODO(), a.lg, rt, a.txnModeWriteWithSharedBuffer, a.kv, a.lessor)
+}
+
+func (a *applierV3backend) Compaction(compaction *pb.CompactionRequest) (*pb.CompactionResponse, <-chan struct{}, *traceutil.Trace, error) {
+	resp := &pb.CompactionResponse{}
+	resp.Header = &pb.ResponseHeader{}
+	trace := traceutil.New("compact",
+		a.lg,
+		traceutil.Field{Key: "revision", Value: compaction.Revision},
+	)
+
+	ch, err := a.kv.Compact(trace, compaction.Revision)
+	if err != nil {
+		return nil, ch, nil, err
+	}
+	// get the current revision. which key to get is not important.
+	rr, _ := a.kv.Range(context.TODO(), []byte("compaction"), nil, mvcc.RangeOptions{})
+	resp.Header.Revision = rr.Rev
+	return resp, ch, trace, err
+}
+
+func (a *applierV3backend) LeaseGrant(lc *pb.LeaseGrantRequest) (*pb.LeaseGrantResponse, error) {
+	l, err := a.lessor.Grant(lease.LeaseID(lc.ID), lc.TTL)
+	resp := &pb.LeaseGrantResponse{}
+	if err == nil {
+		resp.ID = int64(l.ID)
+		resp.TTL = l.TTL()
+		resp.Header = a.newHeader()
+	}
+	return resp, err
+}
+
+func (a *applierV3backend) LeaseRevoke(lc *pb.LeaseRevokeRequest) (*pb.LeaseRevokeResponse, error) {
+	err := a.lessor.Revoke(lease.LeaseID(lc.ID))
+	return &pb.LeaseRevokeResponse{Header: a.newHeader()}, err
+}
+
+func (a *applierV3backend) LeaseCheckpoint(lc *pb.LeaseCheckpointRequest) (*pb.LeaseCheckpointResponse, error) {
+	for _, c := range lc.Checkpoints {
+		err := a.lessor.Checkpoint(lease.LeaseID(c.ID), c.Remaining_TTL)
+		if err != nil {
+			return &pb.LeaseCheckpointResponse{Header: a.newHeader()}, err
+		}
+	}
+	return &pb.LeaseCheckpointResponse{Header: a.newHeader()}, nil
+}
+
+func (a *applierV3backend) Alarm(ar *pb.AlarmRequest) (*pb.AlarmResponse, error) {
+	resp := &pb.AlarmResponse{}
+
+	switch ar.Action {
+	case pb.AlarmRequest_GET:
+		resp.Alarms = a.alarmStore.Get(ar.Alarm)
+	case pb.AlarmRequest_ACTIVATE:
+		if ar.Alarm == pb.AlarmType_NONE {
+			break
+		}
+		m := a.alarmStore.Activate(types.ID(ar.MemberID), ar.Alarm)
+		if m == nil {
+			break
+		}
+		resp.Alarms = append(resp.Alarms, m)
+		alarms.WithLabelValues(types.ID(ar.MemberID).String(), m.Alarm.String()).Inc()
+	case pb.AlarmRequest_DEACTIVATE:
+		m := a.alarmStore.Deactivate(types.ID(ar.MemberID), ar.Alarm)
+		if m == nil {
+			break
+		}
+		resp.Alarms = append(resp.Alarms, m)
+		alarms.WithLabelValues(types.ID(ar.MemberID).String(), m.Alarm.String()).Dec()
+	default:
+		return nil, nil
+	}
+	return resp, nil
+}
+
+type applierV3Capped struct {
+	applierV3
+	q serverstorage.BackendQuota
+}
+
+// newApplierV3Capped creates an applyV3 that will reject Puts and transactions
+// with Puts so that the number of keys in the store is capped.
+func newApplierV3Capped(base applierV3) applierV3 { return &applierV3Capped{applierV3: base} }
+
+func (a *applierV3Capped) Put(_ *pb.PutRequest) (*pb.PutResponse, *traceutil.Trace, error) {
+	return nil, nil, errors.ErrNoSpace
+}
+
+func (a *applierV3Capped) Txn(r *pb.TxnRequest) (*pb.TxnResponse, *traceutil.Trace, error) {
+	if a.q.Cost(r) > 0 {
+		return nil, nil, errors.ErrNoSpace
+	}
+	return a.applierV3.Txn(r)
+}
+
+func (a *applierV3Capped) LeaseGrant(_ *pb.LeaseGrantRequest) (*pb.LeaseGrantResponse, error) {
+	return nil, errors.ErrNoSpace
+}
+
+func (a *applierV3backend) AuthEnable() (*pb.AuthEnableResponse, error) {
+	err := a.authStore.AuthEnable()
+	if err != nil {
+		return nil, err
+	}
+	return &pb.AuthEnableResponse{Header: a.newHeader()}, nil
+}
+
+func (a *applierV3backend) AuthDisable() (*pb.AuthDisableResponse, error) {
+	a.authStore.AuthDisable()
+	return &pb.AuthDisableResponse{Header: a.newHeader()}, nil
+}
+
+func (a *applierV3backend) AuthStatus() (*pb.AuthStatusResponse, error) {
+	enabled := a.authStore.IsAuthEnabled()
+	authRevision := a.authStore.Revision()
+	return &pb.AuthStatusResponse{Header: a.newHeader(), Enabled: enabled, AuthRevision: authRevision}, nil
+}
+
+func (a *applierV3backend) Authenticate(r *pb.InternalAuthenticateRequest) (*pb.AuthenticateResponse, error) {
+	ctx := context.WithValue(context.WithValue(context.Background(), auth.AuthenticateParamIndex{}, a.consistentIndex.ConsistentIndex()), auth.AuthenticateParamSimpleTokenPrefix{}, r.SimpleToken)
+	resp, err := a.authStore.Authenticate(ctx, r.Name, r.Password)
+	if resp != nil {
+		resp.Header = a.newHeader()
+	}
+	return resp, err
+}
+
+func (a *applierV3backend) UserAdd(r *pb.AuthUserAddRequest) (*pb.AuthUserAddResponse, error) {
+	resp, err := a.authStore.UserAdd(r)
+	if resp != nil {
+		resp.Header = a.newHeader()
+	}
+	return resp, err
+}
+
+func (a *applierV3backend) UserDelete(r *pb.AuthUserDeleteRequest) (*pb.AuthUserDeleteResponse, error) {
+	resp, err := a.authStore.UserDelete(r)
+	if resp != nil {
+		resp.Header = a.newHeader()
+	}
+	return resp, err
+}
+
+func (a *applierV3backend) UserChangePassword(r *pb.AuthUserChangePasswordRequest) (*pb.AuthUserChangePasswordResponse, error) {
+	resp, err := a.authStore.UserChangePassword(r)
+	if resp != nil {
+		resp.Header = a.newHeader()
+	}
+	return resp, err
+}
+
+func (a *applierV3backend) UserGrantRole(r *pb.AuthUserGrantRoleRequest) (*pb.AuthUserGrantRoleResponse, error) {
+	resp, err := a.authStore.UserGrantRole(r)
+	if resp != nil {
+		resp.Header = a.newHeader()
+	}
+	return resp, err
+}
+
+func (a *applierV3backend) UserGet(r *pb.AuthUserGetRequest) (*pb.AuthUserGetResponse, error) {
+	resp, err := a.authStore.UserGet(r)
+	if resp != nil {
+		resp.Header = a.newHeader()
+	}
+	return resp, err
+}
+
+func (a *applierV3backend) UserRevokeRole(r *pb.AuthUserRevokeRoleRequest) (*pb.AuthUserRevokeRoleResponse, error) {
+	resp, err := a.authStore.UserRevokeRole(r)
+	if resp != nil {
+		resp.Header = a.newHeader()
+	}
+	return resp, err
+}
+
+func (a *applierV3backend) RoleAdd(r *pb.AuthRoleAddRequest) (*pb.AuthRoleAddResponse, error) {
+	resp, err := a.authStore.RoleAdd(r)
+	if resp != nil {
+		resp.Header = a.newHeader()
+	}
+	return resp, err
+}
+
+func (a *applierV3backend) RoleGrantPermission(r *pb.AuthRoleGrantPermissionRequest) (*pb.AuthRoleGrantPermissionResponse, error) {
+	resp, err := a.authStore.RoleGrantPermission(r)
+	if resp != nil {
+		resp.Header = a.newHeader()
+	}
+	return resp, err
+}
+
+func (a *applierV3backend) RoleGet(r *pb.AuthRoleGetRequest) (*pb.AuthRoleGetResponse, error) {
+	resp, err := a.authStore.RoleGet(r)
+	if resp != nil {
+		resp.Header = a.newHeader()
+	}
+	return resp, err
+}
+
+func (a *applierV3backend) RoleRevokePermission(r *pb.AuthRoleRevokePermissionRequest) (*pb.AuthRoleRevokePermissionResponse, error) {
+	resp, err := a.authStore.RoleRevokePermission(r)
+	if resp != nil {
+		resp.Header = a.newHeader()
+	}
+	return resp, err
+}
+
+func (a *applierV3backend) RoleDelete(r *pb.AuthRoleDeleteRequest) (*pb.AuthRoleDeleteResponse, error) {
+	resp, err := a.authStore.RoleDelete(r)
+	if resp != nil {
+		resp.Header = a.newHeader()
+	}
+	return resp, err
+}
+
+func (a *applierV3backend) UserList(r *pb.AuthUserListRequest) (*pb.AuthUserListResponse, error) {
+	resp, err := a.authStore.UserList(r)
+	if resp != nil {
+		resp.Header = a.newHeader()
+	}
+	return resp, err
+}
+
+func (a *applierV3backend) RoleList(r *pb.AuthRoleListRequest) (*pb.AuthRoleListResponse, error) {
+	resp, err := a.authStore.RoleList(r)
+	if resp != nil {
+		resp.Header = a.newHeader()
+	}
+	return resp, err
+}
+
+type applierMembership struct {
+	lg             *zap.Logger
+	cluster        *membership.RaftCluster
+	snapshotServer SnapshotServer
+}
+
+func NewApplierMembership(lg *zap.Logger, cluster *membership.RaftCluster, snapshotServer SnapshotServer) *applierMembership {
+	return &applierMembership{
+		lg:             lg,
+		cluster:        cluster,
+		snapshotServer: snapshotServer,
+	}
+}
+
+func (a *applierMembership) ClusterVersionSet(r *membershippb.ClusterVersionSetRequest, shouldApplyV3 membership.ShouldApplyV3) {
+	prevVersion := a.cluster.Version()
+	newVersion := semver.Must(semver.NewVersion(r.Ver))
+	a.cluster.SetVersion(newVersion, api.UpdateCapability, shouldApplyV3)
+	// Force snapshot after cluster version downgrade.
+	if prevVersion != nil && newVersion.LessThan(*prevVersion) {
+		lg := a.lg
+		if lg != nil {
+			lg.Info("Cluster version downgrade detected, forcing snapshot",
+				zap.String("prev-cluster-version", prevVersion.String()),
+				zap.String("new-cluster-version", newVersion.String()),
+			)
+		}
+		a.snapshotServer.ForceSnapshot()
+	}
+}
+
+func (a *applierMembership) ClusterMemberAttrSet(r *membershippb.ClusterMemberAttrSetRequest, shouldApplyV3 membership.ShouldApplyV3) {
+	a.cluster.UpdateAttributes(
+		types.ID(r.Member_ID),
+		membership.Attributes{
+			Name:       r.MemberAttributes.Name,
+			ClientURLs: r.MemberAttributes.ClientUrls,
+		},
+		shouldApplyV3,
+	)
+}
+
+func (a *applierMembership) DowngradeInfoSet(r *membershippb.DowngradeInfoSetRequest, shouldApplyV3 membership.ShouldApplyV3) {
+	d := version.DowngradeInfo{Enabled: false}
+	if r.Enabled {
+		d = version.DowngradeInfo{Enabled: true, TargetVersion: r.Ver}
+	}
+	a.cluster.SetDowngradeInfo(&d, shouldApplyV3)
+}
+
+type quotaApplierV3 struct {
+	applierV3
+	q serverstorage.Quota
+}
+
+func newQuotaApplierV3(lg *zap.Logger, quotaBackendBytesCfg int64, be backend.Backend, app applierV3) applierV3 {
+	return &quotaApplierV3{app, serverstorage.NewBackendQuota(lg, quotaBackendBytesCfg, be, "v3-applier")}
+}
+
+func (a *quotaApplierV3) Put(p *pb.PutRequest) (*pb.PutResponse, *traceutil.Trace, error) {
+	ok := a.q.Available(p)
+	resp, trace, err := a.applierV3.Put(p)
+	if err == nil && !ok {
+		err = errors.ErrNoSpace
+	}
+	return resp, trace, err
+}
+
+func (a *quotaApplierV3) Txn(rt *pb.TxnRequest) (*pb.TxnResponse, *traceutil.Trace, error) {
+	ok := a.q.Available(rt)
+	resp, trace, err := a.applierV3.Txn(rt)
+	if err == nil && !ok {
+		err = errors.ErrNoSpace
+	}
+	return resp, trace, err
+}
+
+func (a *quotaApplierV3) LeaseGrant(lc *pb.LeaseGrantRequest) (*pb.LeaseGrantResponse, error) {
+	ok := a.q.Available(lc)
+	resp, err := a.applierV3.LeaseGrant(lc)
+	if err == nil && !ok {
+		err = errors.ErrNoSpace
+	}
+	return resp, err
+}
+
+func (a *applierV3backend) newHeader() *pb.ResponseHeader {
+	return &pb.ResponseHeader{
+		ClusterId: uint64(a.cluster.ID()),
+		MemberId:  uint64(a.raftStatus.MemberID()),
+		Revision:  a.kv.Rev(),
+		RaftTerm:  a.raftStatus.Term(),
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/apply/apply_auth.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/apply/apply_auth.go
new file mode 100644
index 0000000..3922dee
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/apply/apply_auth.go
@@ -0,0 +1,201 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package apply
+
+import (
+	"sync"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/pkg/v3/traceutil"
+	"go.etcd.io/etcd/server/v3/auth"
+	"go.etcd.io/etcd/server/v3/etcdserver/txn"
+	"go.etcd.io/etcd/server/v3/lease"
+)
+
+type authApplierV3 struct {
+	applierV3
+	as     auth.AuthStore
+	lessor lease.Lessor
+
+	// mu serializes Apply so that user isn't corrupted and so that
+	// serialized requests don't leak data from TOCTOU errors
+	mu sync.Mutex
+
+	authInfo auth.AuthInfo
+}
+
+func newAuthApplierV3(as auth.AuthStore, base applierV3, lessor lease.Lessor) *authApplierV3 {
+	return &authApplierV3{applierV3: base, as: as, lessor: lessor}
+}
+
+func (aa *authApplierV3) Apply(r *pb.InternalRaftRequest, applyFunc applyFunc) *Result {
+	aa.mu.Lock()
+	defer aa.mu.Unlock()
+	if r.Header != nil {
+		// backward-compatible with pre-3.0 releases when internalRaftRequest
+		// does not have header field
+		aa.authInfo.Username = r.Header.Username
+		aa.authInfo.Revision = r.Header.AuthRevision
+	}
+	if needAdminPermission(r) {
+		if err := aa.as.IsAdminPermitted(&aa.authInfo); err != nil {
+			aa.authInfo.Username = ""
+			aa.authInfo.Revision = 0
+			return &Result{Err: err}
+		}
+	}
+	ret := aa.applierV3.Apply(r, applyFunc)
+	aa.authInfo.Username = ""
+	aa.authInfo.Revision = 0
+	return ret
+}
+
+func (aa *authApplierV3) Put(r *pb.PutRequest) (*pb.PutResponse, *traceutil.Trace, error) {
+	if err := aa.as.IsPutPermitted(&aa.authInfo, r.Key); err != nil {
+		return nil, nil, err
+	}
+
+	if err := aa.checkLeasePuts(lease.LeaseID(r.Lease)); err != nil {
+		// The specified lease is already attached with a key that cannot
+		// be written by this user. It means the user cannot revoke the
+		// lease so attaching the lease to the newly written key should
+		// be forbidden.
+		return nil, nil, err
+	}
+
+	if r.PrevKv {
+		err := aa.as.IsRangePermitted(&aa.authInfo, r.Key, nil)
+		if err != nil {
+			return nil, nil, err
+		}
+	}
+	return aa.applierV3.Put(r)
+}
+
+func (aa *authApplierV3) Range(r *pb.RangeRequest) (*pb.RangeResponse, *traceutil.Trace, error) {
+	if err := aa.as.IsRangePermitted(&aa.authInfo, r.Key, r.RangeEnd); err != nil {
+		return nil, nil, err
+	}
+	return aa.applierV3.Range(r)
+}
+
+func (aa *authApplierV3) DeleteRange(r *pb.DeleteRangeRequest) (*pb.DeleteRangeResponse, *traceutil.Trace, error) {
+	if err := aa.as.IsDeleteRangePermitted(&aa.authInfo, r.Key, r.RangeEnd); err != nil {
+		return nil, nil, err
+	}
+	if r.PrevKv {
+		err := aa.as.IsRangePermitted(&aa.authInfo, r.Key, r.RangeEnd)
+		if err != nil {
+			return nil, nil, err
+		}
+	}
+
+	return aa.applierV3.DeleteRange(r)
+}
+
+func (aa *authApplierV3) Txn(rt *pb.TxnRequest) (*pb.TxnResponse, *traceutil.Trace, error) {
+	if err := txn.CheckTxnAuth(aa.as, &aa.authInfo, rt); err != nil {
+		return nil, nil, err
+	}
+	return aa.applierV3.Txn(rt)
+}
+
+func (aa *authApplierV3) LeaseRevoke(lc *pb.LeaseRevokeRequest) (*pb.LeaseRevokeResponse, error) {
+	if err := aa.checkLeasePuts(lease.LeaseID(lc.ID)); err != nil {
+		return nil, err
+	}
+	return aa.applierV3.LeaseRevoke(lc)
+}
+
+func (aa *authApplierV3) checkLeasePuts(leaseID lease.LeaseID) error {
+	l := aa.lessor.Lookup(leaseID)
+	if l != nil {
+		return aa.checkLeasePutsKeys(l)
+	}
+
+	return nil
+}
+
+func (aa *authApplierV3) checkLeasePutsKeys(l *lease.Lease) error {
+	// early return for most-common scenario of either disabled auth or admin user.
+	// IsAdminPermitted also checks whether auth is enabled
+	if err := aa.as.IsAdminPermitted(&aa.authInfo); err == nil {
+		return nil
+	}
+
+	for _, key := range l.Keys() {
+		if err := aa.as.IsPutPermitted(&aa.authInfo, []byte(key)); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (aa *authApplierV3) UserGet(r *pb.AuthUserGetRequest) (*pb.AuthUserGetResponse, error) {
+	err := aa.as.IsAdminPermitted(&aa.authInfo)
+	if err != nil && r.Name != aa.authInfo.Username {
+		aa.authInfo.Username = ""
+		aa.authInfo.Revision = 0
+		return &pb.AuthUserGetResponse{}, err
+	}
+
+	return aa.applierV3.UserGet(r)
+}
+
+func (aa *authApplierV3) RoleGet(r *pb.AuthRoleGetRequest) (*pb.AuthRoleGetResponse, error) {
+	err := aa.as.IsAdminPermitted(&aa.authInfo)
+	if err != nil && !aa.as.HasRole(aa.authInfo.Username, r.Role) {
+		aa.authInfo.Username = ""
+		aa.authInfo.Revision = 0
+		return &pb.AuthRoleGetResponse{}, err
+	}
+
+	return aa.applierV3.RoleGet(r)
+}
+
+func needAdminPermission(r *pb.InternalRaftRequest) bool {
+	switch {
+	case r.AuthEnable != nil:
+		return true
+	case r.AuthDisable != nil:
+		return true
+	case r.AuthStatus != nil:
+		return true
+	case r.AuthUserAdd != nil:
+		return true
+	case r.AuthUserDelete != nil:
+		return true
+	case r.AuthUserChangePassword != nil:
+		return true
+	case r.AuthUserGrantRole != nil:
+		return true
+	case r.AuthUserRevokeRole != nil:
+		return true
+	case r.AuthRoleAdd != nil:
+		return true
+	case r.AuthRoleGrantPermission != nil:
+		return true
+	case r.AuthRoleRevokePermission != nil:
+		return true
+	case r.AuthRoleDelete != nil:
+		return true
+	case r.AuthUserList != nil:
+		return true
+	case r.AuthRoleList != nil:
+		return true
+	default:
+		return false
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/apply/corrupt.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/apply/corrupt.go
new file mode 100644
index 0000000..c198119
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/apply/corrupt.go
@@ -0,0 +1,55 @@
+// Copyright 2022 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package apply
+
+import (
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/pkg/v3/traceutil"
+	"go.etcd.io/etcd/server/v3/etcdserver/errors"
+)
+
+type applierV3Corrupt struct {
+	applierV3
+}
+
+func newApplierV3Corrupt(a applierV3) *applierV3Corrupt { return &applierV3Corrupt{a} }
+
+func (a *applierV3Corrupt) Put(_ *pb.PutRequest) (*pb.PutResponse, *traceutil.Trace, error) {
+	return nil, nil, errors.ErrCorrupt
+}
+
+func (a *applierV3Corrupt) Range(_ *pb.RangeRequest) (*pb.RangeResponse, *traceutil.Trace, error) {
+	return nil, nil, errors.ErrCorrupt
+}
+
+func (a *applierV3Corrupt) DeleteRange(_ *pb.DeleteRangeRequest) (*pb.DeleteRangeResponse, *traceutil.Trace, error) {
+	return nil, nil, errors.ErrCorrupt
+}
+
+func (a *applierV3Corrupt) Txn(_ *pb.TxnRequest) (*pb.TxnResponse, *traceutil.Trace, error) {
+	return nil, nil, errors.ErrCorrupt
+}
+
+func (a *applierV3Corrupt) Compaction(_ *pb.CompactionRequest) (*pb.CompactionResponse, <-chan struct{}, *traceutil.Trace, error) {
+	return nil, nil, nil, errors.ErrCorrupt
+}
+
+func (a *applierV3Corrupt) LeaseGrant(_ *pb.LeaseGrantRequest) (*pb.LeaseGrantResponse, error) {
+	return nil, errors.ErrCorrupt
+}
+
+func (a *applierV3Corrupt) LeaseRevoke(_ *pb.LeaseRevokeRequest) (*pb.LeaseRevokeResponse, error) {
+	return nil, errors.ErrCorrupt
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/apply/metrics.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/apply/metrics.go
new file mode 100644
index 0000000..cafbdc7
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/apply/metrics.go
@@ -0,0 +1,31 @@
+// Copyright 2022 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package apply
+
+import "github.com/prometheus/client_golang/prometheus"
+
+var alarms = prometheus.NewGaugeVec(
+	prometheus.GaugeOpts{
+		Namespace: "etcd_debugging",
+		Subsystem: "server",
+		Name:      "alarms",
+		Help:      "Alarms for every member in cluster. 1 for 'server_id' label with current ID. 2 for 'alarm_type' label with type of this alarm",
+	},
+	[]string{"server_id", "alarm_type"},
+)
+
+func init() {
+	prometheus.MustRegister(alarms)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/apply/uber_applier.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/apply/uber_applier.go
new file mode 100644
index 0000000..ec7e2aa
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/apply/uber_applier.go
@@ -0,0 +1,228 @@
+// Copyright 2022 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package apply
+
+import (
+	"errors"
+	"time"
+
+	"go.uber.org/zap"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/server/v3/auth"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/membership"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v3alarm"
+	"go.etcd.io/etcd/server/v3/etcdserver/cindex"
+	"go.etcd.io/etcd/server/v3/etcdserver/txn"
+	"go.etcd.io/etcd/server/v3/lease"
+	"go.etcd.io/etcd/server/v3/storage/backend"
+	"go.etcd.io/etcd/server/v3/storage/mvcc"
+)
+
+type UberApplier interface {
+	Apply(r *pb.InternalRaftRequest) *Result
+}
+
+type uberApplier struct {
+	lg *zap.Logger
+
+	alarmStore           *v3alarm.AlarmStore
+	warningApplyDuration time.Duration
+
+	// This is the applier that is taking in consideration current alarms
+	applyV3 applierV3
+
+	// This is the applier used for wrapping when alarms change
+	applyV3base applierV3
+}
+
+func NewUberApplier(
+	lg *zap.Logger,
+	be backend.Backend,
+	kv mvcc.KV,
+	alarmStore *v3alarm.AlarmStore,
+	authStore auth.AuthStore,
+	lessor lease.Lessor,
+	cluster *membership.RaftCluster,
+	raftStatus RaftStatusGetter,
+	snapshotServer SnapshotServer,
+	consistentIndex cindex.ConsistentIndexer,
+	warningApplyDuration time.Duration,
+	txnModeWriteWithSharedBuffer bool,
+	quotaBackendBytesCfg int64,
+) UberApplier {
+	applyV3base := newApplierV3(lg, be, kv, alarmStore, authStore, lessor, cluster, raftStatus, snapshotServer, consistentIndex, txnModeWriteWithSharedBuffer, quotaBackendBytesCfg)
+
+	ua := &uberApplier{
+		lg:                   lg,
+		alarmStore:           alarmStore,
+		warningApplyDuration: warningApplyDuration,
+		applyV3:              applyV3base,
+		applyV3base:          applyV3base,
+	}
+	ua.restoreAlarms()
+	return ua
+}
+
+func newApplierV3(
+	lg *zap.Logger,
+	be backend.Backend,
+	kv mvcc.KV,
+	alarmStore *v3alarm.AlarmStore,
+	authStore auth.AuthStore,
+	lessor lease.Lessor,
+	cluster *membership.RaftCluster,
+	raftStatus RaftStatusGetter,
+	snapshotServer SnapshotServer,
+	consistentIndex cindex.ConsistentIndexer,
+	txnModeWriteWithSharedBuffer bool,
+	quotaBackendBytesCfg int64,
+) applierV3 {
+	applierBackend := newApplierV3Backend(lg, kv, alarmStore, authStore, lessor, cluster, raftStatus, snapshotServer, consistentIndex, txnModeWriteWithSharedBuffer)
+	return newAuthApplierV3(
+		authStore,
+		newQuotaApplierV3(lg, quotaBackendBytesCfg, be, applierBackend),
+		lessor,
+	)
+}
+
+func (a *uberApplier) restoreAlarms() {
+	noSpaceAlarms := len(a.alarmStore.Get(pb.AlarmType_NOSPACE)) > 0
+	corruptAlarms := len(a.alarmStore.Get(pb.AlarmType_CORRUPT)) > 0
+	a.applyV3 = a.applyV3base
+	if noSpaceAlarms {
+		a.applyV3 = newApplierV3Capped(a.applyV3)
+	}
+	if corruptAlarms {
+		a.applyV3 = newApplierV3Corrupt(a.applyV3)
+	}
+}
+
+func (a *uberApplier) Apply(r *pb.InternalRaftRequest) *Result {
+	// We first execute chain of Apply() calls down the hierarchy:
+	// (i.e. CorruptApplier -> CappedApplier -> Auth -> Quota -> Backend),
+	// then dispatch() unpacks the request to a specific method (like Put),
+	// that gets executed down the hierarchy again:
+	// i.e. CorruptApplier.Put(CappedApplier.Put(...(BackendApplier.Put(...)))).
+	return a.applyV3.Apply(r, a.dispatch)
+}
+
+// dispatch translates the request (r) into appropriate call (like Put) on
+// the underlying applyV3 object.
+func (a *uberApplier) dispatch(r *pb.InternalRaftRequest) *Result {
+	op := "unknown"
+	ar := &Result{}
+	defer func(start time.Time) {
+		success := ar.Err == nil || errors.Is(ar.Err, mvcc.ErrCompacted)
+		txn.ApplySecObserve(v3Version, op, success, time.Since(start))
+		txn.WarnOfExpensiveRequest(a.lg, a.warningApplyDuration, start, &pb.InternalRaftStringer{Request: r}, ar.Resp, ar.Err)
+		if !success {
+			txn.WarnOfFailedRequest(a.lg, start, &pb.InternalRaftStringer{Request: r}, ar.Resp, ar.Err)
+		}
+	}(time.Now())
+
+	switch {
+	case r.Range != nil:
+		op = "Range"
+		ar.Resp, ar.Trace, ar.Err = a.applyV3.Range(r.Range)
+	case r.Put != nil:
+		op = "Put"
+		ar.Resp, ar.Trace, ar.Err = a.applyV3.Put(r.Put)
+	case r.DeleteRange != nil:
+		op = "DeleteRange"
+		ar.Resp, ar.Trace, ar.Err = a.applyV3.DeleteRange(r.DeleteRange)
+	case r.Txn != nil:
+		op = "Txn"
+		ar.Resp, ar.Trace, ar.Err = a.applyV3.Txn(r.Txn)
+	case r.Compaction != nil:
+		op = "Compaction"
+		ar.Resp, ar.Physc, ar.Trace, ar.Err = a.applyV3.Compaction(r.Compaction)
+	case r.LeaseGrant != nil:
+		op = "LeaseGrant"
+		ar.Resp, ar.Err = a.applyV3.LeaseGrant(r.LeaseGrant)
+	case r.LeaseRevoke != nil:
+		op = "LeaseRevoke"
+		ar.Resp, ar.Err = a.applyV3.LeaseRevoke(r.LeaseRevoke)
+	case r.LeaseCheckpoint != nil:
+		op = "LeaseCheckpoint"
+		ar.Resp, ar.Err = a.applyV3.LeaseCheckpoint(r.LeaseCheckpoint)
+	case r.Alarm != nil:
+		op = "Alarm"
+		ar.Resp, ar.Err = a.Alarm(r.Alarm)
+	case r.Authenticate != nil:
+		op = "Authenticate"
+		ar.Resp, ar.Err = a.applyV3.Authenticate(r.Authenticate)
+	case r.AuthEnable != nil:
+		op = "AuthEnable"
+		ar.Resp, ar.Err = a.applyV3.AuthEnable()
+	case r.AuthDisable != nil:
+		op = "AuthDisable"
+		ar.Resp, ar.Err = a.applyV3.AuthDisable()
+	case r.AuthStatus != nil:
+		ar.Resp, ar.Err = a.applyV3.AuthStatus()
+	case r.AuthUserAdd != nil:
+		op = "AuthUserAdd"
+		ar.Resp, ar.Err = a.applyV3.UserAdd(r.AuthUserAdd)
+	case r.AuthUserDelete != nil:
+		op = "AuthUserDelete"
+		ar.Resp, ar.Err = a.applyV3.UserDelete(r.AuthUserDelete)
+	case r.AuthUserChangePassword != nil:
+		op = "AuthUserChangePassword"
+		ar.Resp, ar.Err = a.applyV3.UserChangePassword(r.AuthUserChangePassword)
+	case r.AuthUserGrantRole != nil:
+		op = "AuthUserGrantRole"
+		ar.Resp, ar.Err = a.applyV3.UserGrantRole(r.AuthUserGrantRole)
+	case r.AuthUserGet != nil:
+		op = "AuthUserGet"
+		ar.Resp, ar.Err = a.applyV3.UserGet(r.AuthUserGet)
+	case r.AuthUserRevokeRole != nil:
+		op = "AuthUserRevokeRole"
+		ar.Resp, ar.Err = a.applyV3.UserRevokeRole(r.AuthUserRevokeRole)
+	case r.AuthRoleAdd != nil:
+		op = "AuthRoleAdd"
+		ar.Resp, ar.Err = a.applyV3.RoleAdd(r.AuthRoleAdd)
+	case r.AuthRoleGrantPermission != nil:
+		op = "AuthRoleGrantPermission"
+		ar.Resp, ar.Err = a.applyV3.RoleGrantPermission(r.AuthRoleGrantPermission)
+	case r.AuthRoleGet != nil:
+		op = "AuthRoleGet"
+		ar.Resp, ar.Err = a.applyV3.RoleGet(r.AuthRoleGet)
+	case r.AuthRoleRevokePermission != nil:
+		op = "AuthRoleRevokePermission"
+		ar.Resp, ar.Err = a.applyV3.RoleRevokePermission(r.AuthRoleRevokePermission)
+	case r.AuthRoleDelete != nil:
+		op = "AuthRoleDelete"
+		ar.Resp, ar.Err = a.applyV3.RoleDelete(r.AuthRoleDelete)
+	case r.AuthUserList != nil:
+		op = "AuthUserList"
+		ar.Resp, ar.Err = a.applyV3.UserList(r.AuthUserList)
+	case r.AuthRoleList != nil:
+		op = "AuthRoleList"
+		ar.Resp, ar.Err = a.applyV3.RoleList(r.AuthRoleList)
+	default:
+		a.lg.Panic("not implemented apply", zap.Stringer("raft-request", r))
+	}
+	return ar
+}
+
+func (a *uberApplier) Alarm(ar *pb.AlarmRequest) (*pb.AlarmResponse, error) {
+	resp, err := a.applyV3.Alarm(ar)
+
+	if ar.Action == pb.AlarmRequest_ACTIVATE ||
+		ar.Action == pb.AlarmRequest_DEACTIVATE {
+		a.restoreAlarms()
+	}
+	return resp, err
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/apply_v2.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/apply_v2.go
new file mode 100644
index 0000000..60442fc
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/apply_v2.go
@@ -0,0 +1,64 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package etcdserver
+
+import (
+	"encoding/json"
+	"net/http"
+	"path"
+
+	"go.uber.org/zap"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/api/v3/membershippb"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/membership"
+)
+
+func v2ToV3Request(lg *zap.Logger, r *RequestV2) pb.InternalRaftRequest {
+	if r.Method != http.MethodPut || (!storeMemberAttributeRegexp.MatchString(r.Path) && r.Path != membership.StoreClusterVersionKey()) {
+		lg.Panic("detected disallowed v2 WAL for stage --v2-deprecation=write-only", zap.String("method", r.Method))
+	}
+	if storeMemberAttributeRegexp.MatchString(r.Path) {
+		id := membership.MustParseMemberIDFromKey(lg, path.Dir(r.Path))
+		var attr membership.Attributes
+		if err := json.Unmarshal([]byte(r.Val), &attr); err != nil {
+			lg.Panic("failed to unmarshal", zap.String("value", r.Val), zap.Error(err))
+		}
+		return pb.InternalRaftRequest{
+			Header: &pb.RequestHeader{
+				ID: r.ID,
+			},
+			ClusterMemberAttrSet: &membershippb.ClusterMemberAttrSetRequest{
+				Member_ID: uint64(id),
+				MemberAttributes: &membershippb.Attributes{
+					Name:       attr.Name,
+					ClientUrls: attr.ClientURLs,
+				},
+			},
+		}
+	}
+	if r.Path == membership.StoreClusterVersionKey() {
+		return pb.InternalRaftRequest{
+			Header: &pb.RequestHeader{
+				ID: r.ID,
+			},
+			ClusterVersionSet: &membershippb.ClusterVersionSetRequest{
+				Ver: r.Val,
+			},
+		}
+	}
+	lg.Panic("detected disallowed v2 WAL for stage --v2-deprecation=write-only", zap.String("method", r.Method))
+	return pb.InternalRaftRequest{}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/bootstrap.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/bootstrap.go
new file mode 100644
index 0000000..b76d979
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/bootstrap.go
@@ -0,0 +1,733 @@
+// Copyright 2021 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package etcdserver
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"strings"
+	"time"
+
+	"github.com/coreos/go-semver/semver"
+	"github.com/dustin/go-humanize"
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/client/pkg/v3/fileutil"
+	"go.etcd.io/etcd/client/pkg/v3/types"
+	"go.etcd.io/etcd/pkg/v3/pbutil"
+	"go.etcd.io/etcd/server/v3/config"
+	"go.etcd.io/etcd/server/v3/etcdserver/api"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/membership"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/snap"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v2discovery"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v2store"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v3discovery"
+	"go.etcd.io/etcd/server/v3/etcdserver/cindex"
+	servererrors "go.etcd.io/etcd/server/v3/etcdserver/errors"
+	serverstorage "go.etcd.io/etcd/server/v3/storage"
+	"go.etcd.io/etcd/server/v3/storage/backend"
+	"go.etcd.io/etcd/server/v3/storage/schema"
+	"go.etcd.io/etcd/server/v3/storage/wal"
+	"go.etcd.io/etcd/server/v3/storage/wal/walpb"
+	"go.etcd.io/raft/v3"
+	"go.etcd.io/raft/v3/raftpb"
+)
+
+func bootstrap(cfg config.ServerConfig) (b *bootstrappedServer, err error) {
+	if cfg.MaxRequestBytes > recommendedMaxRequestBytes {
+		cfg.Logger.Warn(
+			"exceeded recommended request limit",
+			zap.Uint("max-request-bytes", cfg.MaxRequestBytes),
+			zap.String("max-request-size", humanize.Bytes(uint64(cfg.MaxRequestBytes))),
+			zap.Int("recommended-request-bytes", recommendedMaxRequestBytes),
+			zap.String("recommended-request-size", recommendedMaxRequestBytesString),
+		)
+	}
+
+	if terr := fileutil.TouchDirAll(cfg.Logger, cfg.DataDir); terr != nil {
+		return nil, fmt.Errorf("cannot access data directory: %w", terr)
+	}
+
+	if terr := fileutil.TouchDirAll(cfg.Logger, cfg.MemberDir()); terr != nil {
+		return nil, fmt.Errorf("cannot access member directory: %w", terr)
+	}
+	ss := bootstrapSnapshot(cfg)
+	prt, err := rafthttp.NewRoundTripper(cfg.PeerTLSInfo, cfg.PeerDialTimeout())
+	if err != nil {
+		return nil, err
+	}
+
+	haveWAL := wal.Exist(cfg.WALDir())
+	st := v2store.New(StoreClusterPrefix, StoreKeysPrefix)
+	backend, err := bootstrapBackend(cfg, haveWAL, st, ss)
+	if err != nil {
+		return nil, err
+	}
+	var bwal *bootstrappedWAL
+
+	if haveWAL {
+		if err = fileutil.IsDirWriteable(cfg.WALDir()); err != nil {
+			return nil, fmt.Errorf("cannot write to WAL directory: %w", err)
+		}
+		cfg.Logger.Info("Bootstrapping WAL from snapshot")
+		bwal = bootstrapWALFromSnapshot(cfg, backend.snapshot, backend.ci)
+	}
+
+	cfg.Logger.Info("bootstrapping cluster")
+	cluster, err := bootstrapCluster(cfg, bwal, prt)
+	if err != nil {
+		backend.Close()
+		return nil, err
+	}
+
+	cfg.Logger.Info("bootstrapping storage")
+	s := bootstrapStorage(cfg, st, backend, bwal, cluster)
+
+	if err = cluster.Finalize(cfg, s); err != nil {
+		backend.Close()
+		return nil, err
+	}
+
+	cfg.Logger.Info("bootstrapping raft")
+	raft := bootstrapRaft(cfg, cluster, s.wal)
+	return &bootstrappedServer{
+		prt:     prt,
+		ss:      ss,
+		storage: s,
+		cluster: cluster,
+		raft:    raft,
+	}, nil
+}
+
+type bootstrappedServer struct {
+	storage *bootstrappedStorage
+	cluster *bootstrappedCluster
+	raft    *bootstrappedRaft
+	prt     http.RoundTripper
+	ss      *snap.Snapshotter
+}
+
+func (s *bootstrappedServer) Close() {
+	s.storage.Close()
+}
+
+type bootstrappedStorage struct {
+	backend *bootstrappedBackend
+	wal     *bootstrappedWAL
+	st      v2store.Store
+}
+
+func (s *bootstrappedStorage) Close() {
+	s.backend.Close()
+}
+
+type bootstrappedBackend struct {
+	beHooks  *serverstorage.BackendHooks
+	be       backend.Backend
+	ci       cindex.ConsistentIndexer
+	beExist  bool
+	snapshot *raftpb.Snapshot
+}
+
+func (s *bootstrappedBackend) Close() {
+	s.be.Close()
+}
+
+type bootstrappedCluster struct {
+	remotes []*membership.Member
+	cl      *membership.RaftCluster
+	nodeID  types.ID
+}
+
+type bootstrappedRaft struct {
+	lg        *zap.Logger
+	heartbeat time.Duration
+
+	peers   []raft.Peer
+	config  *raft.Config
+	storage *raft.MemoryStorage
+}
+
+func bootstrapStorage(cfg config.ServerConfig, st v2store.Store, be *bootstrappedBackend, wal *bootstrappedWAL, cl *bootstrappedCluster) *bootstrappedStorage {
+	if wal == nil {
+		wal = bootstrapNewWAL(cfg, cl)
+	}
+
+	return &bootstrappedStorage{
+		backend: be,
+		st:      st,
+		wal:     wal,
+	}
+}
+
+func bootstrapSnapshot(cfg config.ServerConfig) *snap.Snapshotter {
+	if err := fileutil.TouchDirAll(cfg.Logger, cfg.SnapDir()); err != nil {
+		cfg.Logger.Fatal(
+			"failed to create snapshot directory",
+			zap.String("path", cfg.SnapDir()),
+			zap.Error(err),
+		)
+	}
+
+	if err := fileutil.RemoveMatchFile(cfg.Logger, cfg.SnapDir(), func(fileName string) bool {
+		return strings.HasPrefix(fileName, "tmp")
+	}); err != nil {
+		cfg.Logger.Error(
+			"failed to remove temp file(s) in snapshot directory",
+			zap.String("path", cfg.SnapDir()),
+			zap.Error(err),
+		)
+	}
+	return snap.New(cfg.Logger, cfg.SnapDir())
+}
+
+func bootstrapBackend(cfg config.ServerConfig, haveWAL bool, st v2store.Store, ss *snap.Snapshotter) (backend *bootstrappedBackend, err error) {
+	beExist := fileutil.Exist(cfg.BackendPath())
+	ci := cindex.NewConsistentIndex(nil)
+	beHooks := serverstorage.NewBackendHooks(cfg.Logger, ci)
+	be := serverstorage.OpenBackend(cfg, beHooks)
+	defer func() {
+		if err != nil && be != nil {
+			be.Close()
+		}
+	}()
+	ci.SetBackend(be)
+	schema.CreateMetaBucket(be.BatchTx())
+	if cfg.BootstrapDefragThresholdMegabytes != 0 {
+		err = maybeDefragBackend(cfg, be)
+		if err != nil {
+			return nil, err
+		}
+	}
+	cfg.Logger.Info("restore consistentIndex", zap.Uint64("index", ci.ConsistentIndex()))
+
+	// TODO(serathius): Implement schema setup in fresh storage
+	var snapshot *raftpb.Snapshot
+	if haveWAL {
+		snapshot, be, err = recoverSnapshot(cfg, st, be, beExist, beHooks, ci, ss)
+		if err != nil {
+			return nil, err
+		}
+	}
+	if beExist {
+		s1, s2 := be.Size(), be.SizeInUse()
+		cfg.Logger.Info(
+			"recovered v3 backend",
+			zap.Int64("backend-size-bytes", s1),
+			zap.String("backend-size", humanize.Bytes(uint64(s1))),
+			zap.Int64("backend-size-in-use-bytes", s2),
+			zap.String("backend-size-in-use", humanize.Bytes(uint64(s2))),
+		)
+		if err = schema.Validate(cfg.Logger, be.ReadTx()); err != nil {
+			cfg.Logger.Error("Failed to validate schema", zap.Error(err))
+			return nil, err
+		}
+	}
+
+	return &bootstrappedBackend{
+		beHooks:  beHooks,
+		be:       be,
+		ci:       ci,
+		beExist:  beExist,
+		snapshot: snapshot,
+	}, nil
+}
+
+func maybeDefragBackend(cfg config.ServerConfig, be backend.Backend) error {
+	size := be.Size()
+	sizeInUse := be.SizeInUse()
+	freeableMemory := uint(size - sizeInUse)
+	thresholdBytes := cfg.BootstrapDefragThresholdMegabytes * 1024 * 1024
+	if freeableMemory < thresholdBytes {
+		cfg.Logger.Info("Skipping defragmentation",
+			zap.Int64("current-db-size-bytes", size),
+			zap.String("current-db-size", humanize.Bytes(uint64(size))),
+			zap.Int64("current-db-size-in-use-bytes", sizeInUse),
+			zap.String("current-db-size-in-use", humanize.Bytes(uint64(sizeInUse))),
+			zap.Uint("experimental-bootstrap-defrag-threshold-bytes", thresholdBytes),
+			zap.String("experimental-bootstrap-defrag-threshold", humanize.Bytes(uint64(thresholdBytes))),
+		)
+		return nil
+	}
+	return be.Defrag()
+}
+
+func bootstrapCluster(cfg config.ServerConfig, bwal *bootstrappedWAL, prt http.RoundTripper) (c *bootstrappedCluster, err error) {
+	switch {
+	case bwal == nil && !cfg.NewCluster:
+		c, err = bootstrapExistingClusterNoWAL(cfg, prt)
+	case bwal == nil && cfg.NewCluster:
+		c, err = bootstrapNewClusterNoWAL(cfg, prt)
+	case bwal != nil && bwal.haveWAL:
+		c, err = bootstrapClusterWithWAL(cfg, bwal.meta)
+	default:
+		return nil, fmt.Errorf("unsupported bootstrap config")
+	}
+	if err != nil {
+		return nil, err
+	}
+	return c, nil
+}
+
+func bootstrapExistingClusterNoWAL(cfg config.ServerConfig, prt http.RoundTripper) (*bootstrappedCluster, error) {
+	if err := cfg.VerifyJoinExisting(); err != nil {
+		return nil, err
+	}
+	cl, err := membership.NewClusterFromURLsMap(cfg.Logger, cfg.InitialClusterToken, cfg.InitialPeerURLsMap, membership.WithMaxLearners(cfg.MaxLearners))
+	if err != nil {
+		return nil, err
+	}
+	existingCluster, gerr := GetClusterFromRemotePeers(cfg.Logger, getRemotePeerURLs(cl, cfg.Name), prt)
+	if gerr != nil {
+		return nil, fmt.Errorf("cannot fetch cluster info from peer urls: %w", gerr)
+	}
+	if err := membership.ValidateClusterAndAssignIDs(cfg.Logger, cl, existingCluster); err != nil {
+		return nil, fmt.Errorf("error validating peerURLs %s: %w", existingCluster, err)
+	}
+	if !isCompatibleWithCluster(cfg.Logger, cl, cl.MemberByName(cfg.Name).ID, prt, cfg.ReqTimeout()) {
+		return nil, fmt.Errorf("incompatible with current running cluster")
+	}
+	scaleUpLearners := false
+	if err := membership.ValidateMaxLearnerConfig(cfg.MaxLearners, existingCluster.Members(), scaleUpLearners); err != nil {
+		return nil, err
+	}
+	remotes := existingCluster.Members()
+	cl.SetID(types.ID(0), existingCluster.ID())
+	member := cl.MemberByName(cfg.Name)
+	return &bootstrappedCluster{
+		remotes: remotes,
+		cl:      cl,
+		nodeID:  member.ID,
+	}, nil
+}
+
+func bootstrapNewClusterNoWAL(cfg config.ServerConfig, prt http.RoundTripper) (*bootstrappedCluster, error) {
+	if err := cfg.VerifyBootstrap(); err != nil {
+		return nil, err
+	}
+	cl, err := membership.NewClusterFromURLsMap(cfg.Logger, cfg.InitialClusterToken, cfg.InitialPeerURLsMap, membership.WithMaxLearners(cfg.MaxLearners))
+	if err != nil {
+		return nil, err
+	}
+	m := cl.MemberByName(cfg.Name)
+	if isMemberBootstrapped(cfg.Logger, cl, cfg.Name, prt, cfg.BootstrapTimeoutEffective()) {
+		return nil, fmt.Errorf("member %s has already been bootstrapped", m.ID)
+	}
+	if cfg.ShouldDiscover() {
+		var str string
+		if cfg.DiscoveryURL != "" {
+			cfg.Logger.Warn("V2 discovery is deprecated!")
+			str, err = v2discovery.JoinCluster(cfg.Logger, cfg.DiscoveryURL, cfg.DiscoveryProxy, m.ID, cfg.InitialPeerURLsMap.String())
+		} else {
+			cfg.Logger.Info("Bootstrapping cluster using v3 discovery.")
+			str, err = v3discovery.JoinCluster(cfg.Logger, &cfg.DiscoveryCfg, m.ID, cfg.InitialPeerURLsMap.String())
+		}
+		if err != nil {
+			return nil, &servererrors.DiscoveryError{Op: "join", Err: err}
+		}
+		var urlsmap types.URLsMap
+		urlsmap, err = types.NewURLsMap(str)
+		if err != nil {
+			return nil, err
+		}
+		if config.CheckDuplicateURL(urlsmap) {
+			return nil, fmt.Errorf("discovery cluster %s has duplicate url", urlsmap)
+		}
+		if cl, err = membership.NewClusterFromURLsMap(cfg.Logger, cfg.InitialClusterToken, urlsmap, membership.WithMaxLearners(cfg.MaxLearners)); err != nil {
+			return nil, err
+		}
+	}
+	return &bootstrappedCluster{
+		remotes: nil,
+		cl:      cl,
+		nodeID:  m.ID,
+	}, nil
+}
+
+func bootstrapClusterWithWAL(cfg config.ServerConfig, meta *snapshotMetadata) (*bootstrappedCluster, error) {
+	if err := fileutil.IsDirWriteable(cfg.MemberDir()); err != nil {
+		return nil, fmt.Errorf("cannot write to member directory: %w", err)
+	}
+
+	if cfg.ShouldDiscover() {
+		cfg.Logger.Warn(
+			"discovery token is ignored since cluster already initialized; valid logs are found",
+			zap.String("wal-dir", cfg.WALDir()),
+		)
+	}
+	cl := membership.NewCluster(cfg.Logger, membership.WithMaxLearners(cfg.MaxLearners))
+
+	scaleUpLearners := false
+	if err := membership.ValidateMaxLearnerConfig(cfg.MaxLearners, cl.Members(), scaleUpLearners); err != nil {
+		return nil, err
+	}
+
+	cl.SetID(meta.nodeID, meta.clusterID)
+	return &bootstrappedCluster{
+		cl:     cl,
+		nodeID: meta.nodeID,
+	}, nil
+}
+
+func recoverSnapshot(cfg config.ServerConfig, st v2store.Store, be backend.Backend, beExist bool, beHooks *serverstorage.BackendHooks, ci cindex.ConsistentIndexer, ss *snap.Snapshotter) (*raftpb.Snapshot, backend.Backend, error) {
+	// Find a snapshot to start/restart a raft node
+	walSnaps, err := wal.ValidSnapshotEntries(cfg.Logger, cfg.WALDir())
+	if err != nil {
+		return nil, be, err
+	}
+	// snapshot files can be orphaned if etcd crashes after writing them but before writing the corresponding
+	// bwal log entries
+	snapshot, err := ss.LoadNewestAvailable(walSnaps)
+	if err != nil && !errors.Is(err, snap.ErrNoSnapshot) {
+		return nil, be, err
+	}
+
+	if snapshot != nil {
+		if err = st.Recovery(snapshot.Data); err != nil {
+			cfg.Logger.Panic("failed to recover from snapshot", zap.Error(err))
+		}
+
+		if err = serverstorage.AssertNoV2StoreContent(cfg.Logger, st, cfg.V2Deprecation); err != nil {
+			cfg.Logger.Error("illegal v2store content", zap.Error(err))
+			return nil, be, err
+		}
+
+		cfg.Logger.Info(
+			"recovered v2 store from snapshot",
+			zap.Uint64("snapshot-index", snapshot.Metadata.Index),
+			zap.String("snapshot-size", humanize.Bytes(uint64(snapshot.Size()))),
+		)
+
+		if be, err = serverstorage.RecoverSnapshotBackend(cfg, be, *snapshot, beExist, beHooks); err != nil {
+			cfg.Logger.Panic("failed to recover v3 backend from snapshot", zap.Error(err))
+		}
+		// A snapshot db may have already been recovered, and the old db should have
+		// already been closed in this case, so we should set the backend again.
+		ci.SetBackend(be)
+
+		if beExist {
+			// TODO: remove kvindex != 0 checking when we do not expect users to upgrade
+			// etcd from pre-3.0 release.
+			kvindex := ci.ConsistentIndex()
+			if kvindex < snapshot.Metadata.Index {
+				if kvindex != 0 {
+					return nil, be, fmt.Errorf("database file (%v index %d) does not match with snapshot (index %d)", cfg.BackendPath(), kvindex, snapshot.Metadata.Index)
+				}
+				cfg.Logger.Warn(
+					"consistent index was never saved",
+					zap.Uint64("snapshot-index", snapshot.Metadata.Index),
+				)
+			}
+		}
+	} else {
+		cfg.Logger.Info("No snapshot found. Recovering WAL from scratch!")
+	}
+	return snapshot, be, nil
+}
+
+func (c *bootstrappedCluster) Finalize(cfg config.ServerConfig, s *bootstrappedStorage) error {
+	if !s.wal.haveWAL {
+		c.cl.SetID(c.nodeID, c.cl.ID())
+	}
+	c.cl.SetStore(s.st)
+	c.cl.SetBackend(schema.NewMembershipBackend(cfg.Logger, s.backend.be))
+
+	// Workaround the issues which have already been affected
+	// by https://github.com/etcd-io/etcd/issues/19557.
+	c.cl.SyncLearnerPromotionIfNeeded()
+
+	if s.wal.haveWAL {
+		c.cl.Recover(api.UpdateCapability)
+		if c.databaseFileMissing(s) {
+			bepath := cfg.BackendPath()
+			os.RemoveAll(bepath)
+			return fmt.Errorf("database file (%v) of the backend is missing", bepath)
+		}
+	}
+	scaleUpLearners := false
+	return membership.ValidateMaxLearnerConfig(cfg.MaxLearners, c.cl.Members(), scaleUpLearners)
+}
+
+func (c *bootstrappedCluster) databaseFileMissing(s *bootstrappedStorage) bool {
+	v3Cluster := c.cl.Version() != nil && !c.cl.Version().LessThan(semver.Version{Major: 3})
+	return v3Cluster && !s.backend.beExist
+}
+
+func bootstrapRaft(cfg config.ServerConfig, cluster *bootstrappedCluster, bwal *bootstrappedWAL) *bootstrappedRaft {
+	switch {
+	case !bwal.haveWAL && !cfg.NewCluster:
+		return bootstrapRaftFromCluster(cfg, cluster.cl, nil, bwal)
+	case !bwal.haveWAL && cfg.NewCluster:
+		return bootstrapRaftFromCluster(cfg, cluster.cl, cluster.cl.MemberIDs(), bwal)
+	case bwal.haveWAL:
+		return bootstrapRaftFromWAL(cfg, bwal)
+	default:
+		cfg.Logger.Panic("unsupported bootstrap config")
+		return nil
+	}
+}
+
+func bootstrapRaftFromCluster(cfg config.ServerConfig, cl *membership.RaftCluster, ids []types.ID, bwal *bootstrappedWAL) *bootstrappedRaft {
+	member := cl.MemberByName(cfg.Name)
+	peers := make([]raft.Peer, len(ids))
+	for i, id := range ids {
+		var ctx []byte
+		ctx, err := json.Marshal((*cl).Member(id))
+		if err != nil {
+			cfg.Logger.Panic("failed to marshal member", zap.Error(err))
+		}
+		peers[i] = raft.Peer{ID: uint64(id), Context: ctx}
+	}
+	cfg.Logger.Info(
+		"starting local member",
+		zap.String("local-member-id", member.ID.String()),
+		zap.String("cluster-id", cl.ID().String()),
+	)
+	s := bwal.MemoryStorage()
+	return &bootstrappedRaft{
+		lg:        cfg.Logger,
+		heartbeat: time.Duration(cfg.TickMs) * time.Millisecond,
+		config:    raftConfig(cfg, uint64(member.ID), s),
+		peers:     peers,
+		storage:   s,
+	}
+}
+
+func bootstrapRaftFromWAL(cfg config.ServerConfig, bwal *bootstrappedWAL) *bootstrappedRaft {
+	s := bwal.MemoryStorage()
+	return &bootstrappedRaft{
+		lg:        cfg.Logger,
+		heartbeat: time.Duration(cfg.TickMs) * time.Millisecond,
+		config:    raftConfig(cfg, uint64(bwal.meta.nodeID), s),
+		storage:   s,
+	}
+}
+
+func raftConfig(cfg config.ServerConfig, id uint64, s *raft.MemoryStorage) *raft.Config {
+	return &raft.Config{
+		ID:              id,
+		ElectionTick:    cfg.ElectionTicks,
+		HeartbeatTick:   1,
+		Storage:         s,
+		MaxSizePerMsg:   maxSizePerMsg,
+		MaxInflightMsgs: maxInflightMsgs,
+		CheckQuorum:     true,
+		PreVote:         cfg.PreVote,
+		Logger:          NewRaftLoggerZap(cfg.Logger.Named("raft")),
+	}
+}
+
+func (b *bootstrappedRaft) newRaftNode(ss *snap.Snapshotter, wal *wal.WAL, cl *membership.RaftCluster) *raftNode {
+	var n raft.Node
+	if len(b.peers) == 0 {
+		n = raft.RestartNode(b.config)
+	} else {
+		n = raft.StartNode(b.config, b.peers)
+	}
+	raftStatusMu.Lock()
+	raftStatus = n.Status
+	raftStatusMu.Unlock()
+	return newRaftNode(
+		raftNodeConfig{
+			lg:          b.lg,
+			isIDRemoved: func(id uint64) bool { return cl.IsIDRemoved(types.ID(id)) },
+			Node:        n,
+			heartbeat:   b.heartbeat,
+			raftStorage: b.storage,
+			storage:     serverstorage.NewStorage(b.lg, wal, ss),
+		},
+	)
+}
+
+func bootstrapWALFromSnapshot(cfg config.ServerConfig, snapshot *raftpb.Snapshot, ci cindex.ConsistentIndexer) *bootstrappedWAL {
+	wal, st, ents, snap, meta := openWALFromSnapshot(cfg, snapshot)
+	bwal := &bootstrappedWAL{
+		lg:       cfg.Logger,
+		w:        wal,
+		st:       st,
+		ents:     ents,
+		snapshot: snap,
+		meta:     meta,
+		haveWAL:  true,
+	}
+
+	if cfg.ForceNewCluster {
+		consistentIndex := ci.ConsistentIndex()
+		oldCommitIndex := bwal.st.Commit
+		// If only `HardState.Commit` increases, HardState won't be persisted
+		// to disk, even though the committed entries might have already been
+		// applied. This can result in consistent_index > CommitIndex.
+		//
+		// When restarting etcd with `--force-new-cluster`, all uncommitted
+		// entries are dropped. To avoid losing entries that were actually
+		// committed, we reset Commit to max(HardState.Commit, consistent_index).
+		//
+		// See: https://github.com/etcd-io/raft/pull/300 for more details.
+		bwal.st.Commit = max(oldCommitIndex, consistentIndex)
+
+		// discard the previously uncommitted entries
+		bwal.ents = bwal.CommitedEntries()
+		entries := bwal.NewConfigChangeEntries()
+		// force commit config change entries
+		bwal.AppendAndCommitEntries(entries)
+		cfg.Logger.Info(
+			"forcing restart member",
+			zap.String("cluster-id", meta.clusterID.String()),
+			zap.String("local-member-id", meta.nodeID.String()),
+			zap.Uint64("wal-commit-index", oldCommitIndex),
+			zap.Uint64("commit-index", bwal.st.Commit),
+		)
+	} else {
+		cfg.Logger.Info(
+			"restarting local member",
+			zap.String("cluster-id", meta.clusterID.String()),
+			zap.String("local-member-id", meta.nodeID.String()),
+			zap.Uint64("commit-index", bwal.st.Commit),
+		)
+	}
+	return bwal
+}
+
+// openWALFromSnapshot reads the WAL at the given snap and returns the wal, its latest HardState and cluster ID, and all entries that appear
+// after the position of the given snap in the WAL.
+// The snap must have been previously saved to the WAL, or this call will panic.
+func openWALFromSnapshot(cfg config.ServerConfig, snapshot *raftpb.Snapshot) (*wal.WAL, *raftpb.HardState, []raftpb.Entry, *raftpb.Snapshot, *snapshotMetadata) {
+	var walsnap walpb.Snapshot
+	if snapshot != nil {
+		walsnap.Index, walsnap.Term = snapshot.Metadata.Index, snapshot.Metadata.Term
+	}
+	repaired := false
+	for {
+		w, err := wal.Open(cfg.Logger, cfg.WALDir(), walsnap)
+		if err != nil {
+			cfg.Logger.Fatal("failed to open WAL", zap.Error(err))
+		}
+		if cfg.UnsafeNoFsync {
+			w.SetUnsafeNoFsync()
+		}
+		wmetadata, st, ents, err := w.ReadAll()
+		if err != nil {
+			w.Close()
+			// we can only repair ErrUnexpectedEOF and we never repair twice.
+			if repaired || !errors.Is(err, io.ErrUnexpectedEOF) {
+				cfg.Logger.Fatal("failed to read WAL, cannot be repaired", zap.Error(err))
+			}
+			if !wal.Repair(cfg.Logger, cfg.WALDir()) {
+				cfg.Logger.Fatal("failed to repair WAL", zap.Error(err))
+			} else {
+				cfg.Logger.Info("repaired WAL", zap.Error(err))
+				repaired = true
+			}
+			continue
+		}
+		var metadata etcdserverpb.Metadata
+		pbutil.MustUnmarshal(&metadata, wmetadata)
+		id := types.ID(metadata.NodeID)
+		cid := types.ID(metadata.ClusterID)
+		meta := &snapshotMetadata{clusterID: cid, nodeID: id}
+		return w, &st, ents, snapshot, meta
+	}
+}
+
+type snapshotMetadata struct {
+	nodeID, clusterID types.ID
+}
+
+func bootstrapNewWAL(cfg config.ServerConfig, cl *bootstrappedCluster) *bootstrappedWAL {
+	metadata := pbutil.MustMarshal(
+		&etcdserverpb.Metadata{
+			NodeID:    uint64(cl.nodeID),
+			ClusterID: uint64(cl.cl.ID()),
+		},
+	)
+	w, err := wal.Create(cfg.Logger, cfg.WALDir(), metadata)
+	if err != nil {
+		cfg.Logger.Panic("failed to create WAL", zap.Error(err))
+	}
+	if cfg.UnsafeNoFsync {
+		w.SetUnsafeNoFsync()
+	}
+	return &bootstrappedWAL{
+		lg: cfg.Logger,
+		w:  w,
+	}
+}
+
+type bootstrappedWAL struct {
+	lg *zap.Logger
+
+	haveWAL  bool
+	w        *wal.WAL
+	st       *raftpb.HardState
+	ents     []raftpb.Entry
+	snapshot *raftpb.Snapshot
+	meta     *snapshotMetadata
+}
+
+func (wal *bootstrappedWAL) MemoryStorage() *raft.MemoryStorage {
+	s := raft.NewMemoryStorage()
+	if wal.snapshot != nil {
+		s.ApplySnapshot(*wal.snapshot)
+	}
+	if wal.st != nil {
+		s.SetHardState(*wal.st)
+	}
+	if len(wal.ents) != 0 {
+		s.Append(wal.ents)
+	}
+	return s
+}
+
+func (wal *bootstrappedWAL) CommitedEntries() []raftpb.Entry {
+	for i, ent := range wal.ents {
+		if ent.Index > wal.st.Commit {
+			wal.lg.Info(
+				"discarding uncommitted WAL entries",
+				zap.Uint64("entry-index", ent.Index),
+				zap.Uint64("commit-index-from-wal", wal.st.Commit),
+				zap.Int("number-of-discarded-entries", len(wal.ents)-i),
+			)
+			return wal.ents[:i]
+		}
+	}
+	return wal.ents
+}
+
+func (wal *bootstrappedWAL) NewConfigChangeEntries() []raftpb.Entry {
+	return serverstorage.CreateConfigChangeEnts(
+		wal.lg,
+		serverstorage.GetEffectiveNodeIDsFromWALEntries(wal.lg, wal.snapshot, wal.ents),
+		uint64(wal.meta.nodeID),
+		wal.st.Term,
+		wal.st.Commit,
+	)
+}
+
+func (wal *bootstrappedWAL) AppendAndCommitEntries(ents []raftpb.Entry) {
+	wal.ents = append(wal.ents, ents...)
+	err := wal.w.Save(raftpb.HardState{}, ents)
+	if err != nil {
+		wal.lg.Fatal("failed to save hard state and entries", zap.Error(err))
+	}
+	if len(wal.ents) != 0 {
+		wal.st.Commit = wal.ents[len(wal.ents)-1].Index
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/cindex/cindex.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/cindex/cindex.go
new file mode 100644
index 0000000..b865742
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/cindex/cindex.go
@@ -0,0 +1,178 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cindex
+
+import (
+	"sync"
+	"sync/atomic"
+
+	"go.etcd.io/etcd/server/v3/storage/backend"
+	"go.etcd.io/etcd/server/v3/storage/schema"
+)
+
+type Backend interface {
+	ReadTx() backend.ReadTx
+}
+
+// ConsistentIndexer is an interface that wraps the Get/Set/Save method for consistentIndex.
+type ConsistentIndexer interface {
+	// ConsistentIndex returns the consistent index of current executing entry.
+	ConsistentIndex() uint64
+
+	// ConsistentApplyingIndex returns the consistent applying index of current executing entry.
+	ConsistentApplyingIndex() (uint64, uint64)
+
+	// UnsafeConsistentIndex is similar to ConsistentIndex, but it doesn't lock the transaction.
+	UnsafeConsistentIndex() uint64
+
+	// SetConsistentIndex set the consistent index of current executing entry.
+	SetConsistentIndex(v uint64, term uint64)
+
+	// SetConsistentApplyingIndex set the consistent applying index of current executing entry.
+	SetConsistentApplyingIndex(v uint64, term uint64)
+
+	// UnsafeSave must be called holding the lock on the tx.
+	// It saves consistentIndex to the underlying stable storage.
+	UnsafeSave(tx backend.UnsafeReadWriter)
+
+	// SetBackend set the available backend.BatchTx for ConsistentIndexer.
+	SetBackend(be Backend)
+}
+
+// consistentIndex implements the ConsistentIndexer interface.
+type consistentIndex struct {
+	// consistentIndex represents the offset of an entry in a consistent replica log.
+	// It caches the "consistent_index" key's value.
+	// Accessed through atomics so must be 64-bit aligned.
+	consistentIndex uint64
+	// term represents the RAFT term of committed entry in a consistent replica log.
+	// Accessed through atomics so must be 64-bit aligned.
+	// The value is being persisted in the backend since v3.5.
+	term uint64
+
+	// applyingIndex and applyingTerm are just temporary cache of the raftpb.Entry.Index
+	// and raftpb.Entry.Term, and they are not ready to be persisted yet. They will be
+	// saved to consistentIndex and term above in the txPostLockInsideApplyHook.
+	//
+	// TODO(ahrtr): try to remove the OnPreCommitUnsafe, and compare the
+	//  performance difference. Afterwards we can make a decision on whether
+	//  or not we should remove OnPreCommitUnsafe. If it is true, then we
+	//  can remove applyingIndex and applyingTerm, and save the e.Index and
+	//  e.Term to consistentIndex and term directly in applyEntries, and
+	//  persist them into db in the txPostLockInsideApplyHook.
+	applyingIndex uint64
+	applyingTerm  uint64
+
+	// be is used for initial read consistentIndex
+	be Backend
+	// mutex is protecting be.
+	mutex sync.Mutex
+}
+
+// NewConsistentIndex creates a new consistent index.
+// If `be` is nil, it must be set (SetBackend) before first access using `ConsistentIndex()`.
+func NewConsistentIndex(be Backend) ConsistentIndexer {
+	return &consistentIndex{be: be}
+}
+
+func (ci *consistentIndex) ConsistentIndex() uint64 {
+	if index := atomic.LoadUint64(&ci.consistentIndex); index > 0 {
+		return index
+	}
+	ci.mutex.Lock()
+	defer ci.mutex.Unlock()
+
+	v, term := schema.ReadConsistentIndex(ci.be.ReadTx())
+	ci.SetConsistentIndex(v, term)
+	return v
+}
+
+func (ci *consistentIndex) UnsafeConsistentIndex() uint64 {
+	if index := atomic.LoadUint64(&ci.consistentIndex); index > 0 {
+		return index
+	}
+
+	v, term := schema.UnsafeReadConsistentIndex(ci.be.ReadTx())
+	ci.SetConsistentIndex(v, term)
+	return v
+}
+
+func (ci *consistentIndex) SetConsistentIndex(v uint64, term uint64) {
+	atomic.StoreUint64(&ci.consistentIndex, v)
+	atomic.StoreUint64(&ci.term, term)
+}
+
+func (ci *consistentIndex) UnsafeSave(tx backend.UnsafeReadWriter) {
+	index := atomic.LoadUint64(&ci.consistentIndex)
+	term := atomic.LoadUint64(&ci.term)
+	schema.UnsafeUpdateConsistentIndex(tx, index, term)
+}
+
+func (ci *consistentIndex) SetBackend(be Backend) {
+	ci.mutex.Lock()
+	defer ci.mutex.Unlock()
+	ci.be = be
+	// After the backend is changed, the first access should re-read it.
+	ci.SetConsistentIndex(0, 0)
+}
+
+func (ci *consistentIndex) ConsistentApplyingIndex() (uint64, uint64) {
+	return atomic.LoadUint64(&ci.applyingIndex), atomic.LoadUint64(&ci.applyingTerm)
+}
+
+func (ci *consistentIndex) SetConsistentApplyingIndex(v uint64, term uint64) {
+	atomic.StoreUint64(&ci.applyingIndex, v)
+	atomic.StoreUint64(&ci.applyingTerm, term)
+}
+
+func NewFakeConsistentIndex(index uint64) ConsistentIndexer {
+	return &fakeConsistentIndex{index: index}
+}
+
+type fakeConsistentIndex struct {
+	index uint64
+	term  uint64
+}
+
+func (f *fakeConsistentIndex) ConsistentIndex() uint64 {
+	return atomic.LoadUint64(&f.index)
+}
+
+func (f *fakeConsistentIndex) ConsistentApplyingIndex() (uint64, uint64) {
+	return atomic.LoadUint64(&f.index), atomic.LoadUint64(&f.term)
+}
+
+func (f *fakeConsistentIndex) UnsafeConsistentIndex() uint64 {
+	return atomic.LoadUint64(&f.index)
+}
+
+func (f *fakeConsistentIndex) SetConsistentIndex(index uint64, term uint64) {
+	atomic.StoreUint64(&f.index, index)
+	atomic.StoreUint64(&f.term, term)
+}
+
+func (f *fakeConsistentIndex) SetConsistentApplyingIndex(index uint64, term uint64) {
+	atomic.StoreUint64(&f.index, index)
+	atomic.StoreUint64(&f.term, term)
+}
+
+func (f *fakeConsistentIndex) UnsafeSave(_ backend.UnsafeReadWriter) {}
+func (f *fakeConsistentIndex) SetBackend(_ Backend)                  {}
+
+func UpdateConsistentIndexForce(tx backend.BatchTx, index uint64, term uint64) {
+	tx.LockOutsideApply()
+	defer tx.Unlock()
+	schema.UnsafeUpdateConsistentIndexForce(tx, index, term)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/cindex/doc.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/cindex/doc.go
new file mode 100644
index 0000000..7d3e4b7
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/cindex/doc.go
@@ -0,0 +1,16 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package cindex provides an interface and implementation for getting/saving consistentIndex.
+package cindex
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/cluster_util.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/cluster_util.go
new file mode 100644
index 0000000..425ed97
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/cluster_util.go
@@ -0,0 +1,442 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package etcdserver
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"sort"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/coreos/go-semver/semver"
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/api/v3/version"
+	"go.etcd.io/etcd/client/pkg/v3/types"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/membership"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v2store"
+	"go.etcd.io/etcd/server/v3/etcdserver/errors"
+)
+
+// isMemberBootstrapped tries to check if the given member has been bootstrapped
+// in the given cluster.
+func isMemberBootstrapped(lg *zap.Logger, cl *membership.RaftCluster, member string, rt http.RoundTripper, timeout time.Duration) bool {
+	rcl, err := getClusterFromRemotePeers(lg, getRemotePeerURLs(cl, member), timeout, false, rt)
+	if err != nil {
+		return false
+	}
+	id := cl.MemberByName(member).ID
+	m := rcl.Member(id)
+	if m == nil {
+		return false
+	}
+	if len(m.ClientURLs) > 0 {
+		return true
+	}
+	return false
+}
+
+// GetClusterFromRemotePeers takes a set of URLs representing etcd peers, and
+// attempts to construct a Cluster by accessing the members endpoint on one of
+// these URLs. The first URL to provide a response is used. If no URLs provide
+// a response, or a Cluster cannot be successfully created from a received
+// response, an error is returned.
+// Each request has a 10-second timeout. Because the upper limit of TTL is 5s,
+// 10 second is enough for building connection and finishing request.
+func GetClusterFromRemotePeers(lg *zap.Logger, urls []string, rt http.RoundTripper) (*membership.RaftCluster, error) {
+	return getClusterFromRemotePeers(lg, urls, 10*time.Second, true, rt)
+}
+
+// If logerr is true, it prints out more error messages.
+func getClusterFromRemotePeers(lg *zap.Logger, urls []string, timeout time.Duration, logerr bool, rt http.RoundTripper) (*membership.RaftCluster, error) {
+	if lg == nil {
+		lg = zap.NewNop()
+	}
+	cc := &http.Client{
+		Transport: rt,
+		Timeout:   timeout,
+		CheckRedirect: func(req *http.Request, via []*http.Request) error {
+			return http.ErrUseLastResponse
+		},
+	}
+	for _, u := range urls {
+		addr := u + "/members"
+		resp, err := cc.Get(addr)
+		if err != nil {
+			if logerr {
+				lg.Warn("failed to get cluster response", zap.String("address", addr), zap.Error(err))
+			}
+			continue
+		}
+		b, err := io.ReadAll(resp.Body)
+		resp.Body.Close()
+		if err != nil {
+			if logerr {
+				lg.Warn("failed to read body of cluster response", zap.String("address", addr), zap.Error(err))
+			}
+			continue
+		}
+		var membs []*membership.Member
+		if err = json.Unmarshal(b, &membs); err != nil {
+			if logerr {
+				lg.Warn("failed to unmarshal cluster response", zap.String("address", addr), zap.Error(err))
+			}
+			continue
+		}
+		id, err := types.IDFromString(resp.Header.Get("X-Etcd-Cluster-ID"))
+		if err != nil {
+			if logerr {
+				lg.Warn(
+					"failed to parse cluster ID",
+					zap.String("address", addr),
+					zap.String("header", resp.Header.Get("X-Etcd-Cluster-ID")),
+					zap.Error(err),
+				)
+			}
+			continue
+		}
+
+		// check the length of membership members
+		// if the membership members are present then prepare and return raft cluster
+		// if membership members are not present then the raft cluster formed will be
+		// an invalid empty cluster hence return failed to get raft cluster member(s) from the given urls error
+		if len(membs) > 0 {
+			return membership.NewClusterFromMembers(lg, id, membs), nil
+		}
+		return nil, fmt.Errorf("failed to get raft cluster member(s) from the given URLs")
+	}
+	return nil, fmt.Errorf("could not retrieve cluster information from the given URLs")
+}
+
+// getRemotePeerURLs returns peer urls of remote members in the cluster. The
+// returned list is sorted in ascending lexicographical order.
+func getRemotePeerURLs(cl *membership.RaftCluster, local string) []string {
+	us := make([]string, 0)
+	for _, m := range cl.Members() {
+		if m.Name == local {
+			continue
+		}
+		us = append(us, m.PeerURLs...)
+	}
+	sort.Strings(us)
+	return us
+}
+
+// getMembersVersions returns the versions of the members in the given cluster.
+// The key of the returned map is the member's ID. The value of the returned map
+// is the semver versions string, including server and cluster.
+// If it fails to get the version of a member, the key will be nil.
+func getMembersVersions(lg *zap.Logger, cl *membership.RaftCluster, local types.ID, rt http.RoundTripper, timeout time.Duration) map[string]*version.Versions {
+	members := cl.Members()
+	vers := make(map[string]*version.Versions)
+	for _, m := range members {
+		if m.ID == local {
+			cv := "not_decided"
+			if cl.Version() != nil {
+				cv = cl.Version().String()
+			}
+			vers[m.ID.String()] = &version.Versions{Server: version.Version, Cluster: cv}
+			continue
+		}
+		ver, err := getVersion(lg, m, rt, timeout)
+		if err != nil {
+			lg.Warn("failed to get version", zap.String("remote-member-id", m.ID.String()), zap.Error(err))
+			vers[m.ID.String()] = nil
+		} else {
+			vers[m.ID.String()] = ver
+		}
+	}
+	return vers
+}
+
+// allowedVersionRange decides the available version range of the cluster that local server can join in;
+// if the downgrade enabled status is true, the version window is [oneMinorHigher, oneMinorHigher]
+// if the downgrade is not enabled, the version window is [MinClusterVersion, localVersion]
+func allowedVersionRange(downgradeEnabled bool) (minV *semver.Version, maxV *semver.Version) {
+	minV = semver.Must(semver.NewVersion(version.MinClusterVersion))
+	maxV = semver.Must(semver.NewVersion(version.Version))
+	maxV = &semver.Version{Major: maxV.Major, Minor: maxV.Minor}
+
+	if downgradeEnabled {
+		// Todo: handle the case that downgrading from higher major version(e.g. downgrade from v4.0 to v3.x)
+		maxV.Minor = maxV.Minor + 1
+		minV = &semver.Version{Major: maxV.Major, Minor: maxV.Minor}
+	}
+	return minV, maxV
+}
+
+// isCompatibleWithCluster return true if the local member has a compatible version with
+// the current running cluster.
+// The version is considered as compatible when at least one of the other members in the cluster has a
+// cluster version in the range of [MinV, MaxV] and no known members has a cluster version
+// out of the range.
+// We set this rule since when the local member joins, another member might be offline.
+func isCompatibleWithCluster(lg *zap.Logger, cl *membership.RaftCluster, local types.ID, rt http.RoundTripper, timeout time.Duration) bool {
+	vers := getMembersVersions(lg, cl, local, rt, timeout)
+	minV, maxV := allowedVersionRange(getDowngradeEnabledFromRemotePeers(lg, cl, local, rt, timeout))
+	return isCompatibleWithVers(lg, vers, local, minV, maxV)
+}
+
+func isCompatibleWithVers(lg *zap.Logger, vers map[string]*version.Versions, local types.ID, minV, maxV *semver.Version) bool {
+	var ok bool
+	for id, v := range vers {
+		// ignore comparison with local version
+		if id == local.String() {
+			continue
+		}
+		if v == nil {
+			continue
+		}
+		clusterv, err := semver.NewVersion(v.Cluster)
+		if err != nil {
+			lg.Warn(
+				"failed to parse cluster version of remote member",
+				zap.String("remote-member-id", id),
+				zap.String("remote-member-cluster-version", v.Cluster),
+				zap.Error(err),
+			)
+			continue
+		}
+		if clusterv.LessThan(*minV) {
+			lg.Warn(
+				"cluster version of remote member is not compatible; too low",
+				zap.String("remote-member-id", id),
+				zap.String("remote-member-cluster-version", clusterv.String()),
+				zap.String("minimum-cluster-version-supported", minV.String()),
+			)
+			return false
+		}
+		if maxV.LessThan(*clusterv) {
+			lg.Warn(
+				"cluster version of remote member is not compatible; too high",
+				zap.String("remote-member-id", id),
+				zap.String("remote-member-cluster-version", clusterv.String()),
+				zap.String("maximum-cluster-version-supported", maxV.String()),
+			)
+			return false
+		}
+		ok = true
+	}
+	return ok
+}
+
+// getVersion returns the Versions of the given member via its
+// peerURLs. Returns the last error if it fails to get the version.
+func getVersion(lg *zap.Logger, m *membership.Member, rt http.RoundTripper, timeout time.Duration) (*version.Versions, error) {
+	cc := &http.Client{
+		Transport: rt,
+		Timeout:   timeout,
+		CheckRedirect: func(req *http.Request, via []*http.Request) error {
+			return http.ErrUseLastResponse
+		},
+	}
+	var (
+		err  error
+		resp *http.Response
+	)
+
+	for _, u := range m.PeerURLs {
+		addr := u + "/version"
+		resp, err = cc.Get(addr)
+		if err != nil {
+			lg.Warn(
+				"failed to reach the peer URL",
+				zap.String("address", addr),
+				zap.String("remote-member-id", m.ID.String()),
+				zap.Error(err),
+			)
+			continue
+		}
+		var b []byte
+		b, err = io.ReadAll(resp.Body)
+		resp.Body.Close()
+		if err != nil {
+			lg.Warn(
+				"failed to read body of response",
+				zap.String("address", addr),
+				zap.String("remote-member-id", m.ID.String()),
+				zap.Error(err),
+			)
+			continue
+		}
+		var vers version.Versions
+		if err = json.Unmarshal(b, &vers); err != nil {
+			lg.Warn(
+				"failed to unmarshal response",
+				zap.String("address", addr),
+				zap.String("remote-member-id", m.ID.String()),
+				zap.Error(err),
+			)
+			continue
+		}
+		return &vers, nil
+	}
+	return nil, err
+}
+
+func promoteMemberHTTP(ctx context.Context, url string, id uint64, peerRt http.RoundTripper) ([]*membership.Member, error) {
+	cc := &http.Client{
+		Transport: peerRt,
+		CheckRedirect: func(req *http.Request, via []*http.Request) error {
+			return http.ErrUseLastResponse
+		},
+	}
+	// TODO: refactor member http handler code
+	// cannot import etcdhttp, so manually construct url
+	requestURL := url + "/members/promote/" + fmt.Sprintf("%d", id)
+	req, err := http.NewRequest(http.MethodPost, requestURL, nil)
+	if err != nil {
+		return nil, err
+	}
+	req = req.WithContext(ctx)
+	resp, err := cc.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+	b, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	if resp.StatusCode == http.StatusRequestTimeout {
+		return nil, errors.ErrTimeout
+	}
+	if resp.StatusCode == http.StatusPreconditionFailed {
+		// both ErrMemberNotLearner and ErrLearnerNotReady have same http status code
+		if strings.Contains(string(b), errors.ErrLearnerNotReady.Error()) {
+			return nil, errors.ErrLearnerNotReady
+		}
+		if strings.Contains(string(b), membership.ErrMemberNotLearner.Error()) {
+			return nil, membership.ErrMemberNotLearner
+		}
+		return nil, fmt.Errorf("member promote: unknown error(%s)", b)
+	}
+	if resp.StatusCode == http.StatusNotFound {
+		return nil, membership.ErrIDNotFound
+	}
+
+	if resp.StatusCode != http.StatusOK { // all other types of errors
+		return nil, fmt.Errorf("member promote: unknown error(%s)", b)
+	}
+
+	var membs []*membership.Member
+	if err := json.Unmarshal(b, &membs); err != nil {
+		return nil, err
+	}
+	return membs, nil
+}
+
+// getDowngradeEnabledFromRemotePeers will get the downgrade enabled status of the cluster.
+func getDowngradeEnabledFromRemotePeers(lg *zap.Logger, cl *membership.RaftCluster, local types.ID, rt http.RoundTripper, timeout time.Duration) bool {
+	members := cl.Members()
+
+	for _, m := range members {
+		if m.ID == local {
+			continue
+		}
+		enable, err := getDowngradeEnabled(lg, m, rt, timeout)
+		if err == nil {
+			// Since the "/downgrade/enabled" serves linearized data,
+			// this function can return once it gets a non-error response from the endpoint.
+			return enable
+		}
+		lg.Warn("failed to get downgrade enabled status", zap.String("remote-member-id", m.ID.String()), zap.Error(err))
+	}
+	return false
+}
+
+// getDowngradeEnabled returns the downgrade enabled status of the given member
+// via its peerURLs. Returns the last error if it fails to get it.
+func getDowngradeEnabled(lg *zap.Logger, m *membership.Member, rt http.RoundTripper, timeout time.Duration) (bool, error) {
+	cc := &http.Client{
+		Transport: rt,
+		Timeout:   timeout,
+		CheckRedirect: func(req *http.Request, via []*http.Request) error {
+			return http.ErrUseLastResponse
+		},
+	}
+	var (
+		err  error
+		resp *http.Response
+	)
+
+	for _, u := range m.PeerURLs {
+		addr := u + DowngradeEnabledPath
+		resp, err = cc.Get(addr)
+		if err != nil {
+			lg.Warn(
+				"failed to reach the peer URL",
+				zap.String("address", addr),
+				zap.String("remote-member-id", m.ID.String()),
+				zap.Error(err),
+			)
+			continue
+		}
+		var b []byte
+		b, err = io.ReadAll(resp.Body)
+		resp.Body.Close()
+		if err != nil {
+			lg.Warn(
+				"failed to read body of response",
+				zap.String("address", addr),
+				zap.String("remote-member-id", m.ID.String()),
+				zap.Error(err),
+			)
+			continue
+		}
+		var enable bool
+		if enable, err = strconv.ParseBool(string(b)); err != nil {
+			lg.Warn(
+				"failed to convert response",
+				zap.String("address", addr),
+				zap.String("remote-member-id", m.ID.String()),
+				zap.Error(err),
+			)
+			continue
+		}
+		return enable, nil
+	}
+	return false, err
+}
+
+func convertToClusterVersion(v string) (*semver.Version, error) {
+	ver, err := semver.NewVersion(v)
+	if err != nil {
+		// allow input version format Major.Minor
+		ver, err = semver.NewVersion(v + ".0")
+		if err != nil {
+			return nil, errors.ErrWrongDowngradeVersionFormat
+		}
+	}
+	// cluster version only keeps major.minor, remove patch version
+	ver = &semver.Version{Major: ver.Major, Minor: ver.Minor}
+	return ver, nil
+}
+
+func GetMembershipInfoInV2Format(lg *zap.Logger, cl *membership.RaftCluster) []byte {
+	st := v2store.New(StoreClusterPrefix, StoreKeysPrefix)
+	cl.Store(st)
+	d, err := st.SaveNoCopy()
+	if err != nil {
+		lg.Panic("failed to save v2 store", zap.Error(err))
+	}
+	return d
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/corrupt.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/corrupt.go
new file mode 100644
index 0000000..5ec111b
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/corrupt.go
@@ -0,0 +1,626 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package etcdserver
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"sort"
+	"strings"
+	"sync"
+	"time"
+
+	"go.uber.org/zap"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/api/v3/v3rpc/rpctypes"
+	"go.etcd.io/etcd/client/pkg/v3/types"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp"
+	"go.etcd.io/etcd/server/v3/storage/mvcc"
+)
+
+type CorruptionChecker interface {
+	InitialCheck() error
+	PeriodicCheck() error
+	CompactHashCheck()
+}
+
+type corruptionChecker struct {
+	lg *zap.Logger
+
+	hasher Hasher
+
+	mux                   sync.RWMutex
+	latestRevisionChecked int64
+}
+
+type Hasher interface {
+	mvcc.HashStorage
+	ReqTimeout() time.Duration
+	MemberID() types.ID
+	PeerHashByRev(int64) []*peerHashKVResp
+	LinearizableReadNotify(context.Context) error
+	TriggerCorruptAlarm(types.ID)
+}
+
+func newCorruptionChecker(lg *zap.Logger, s *EtcdServer, storage mvcc.HashStorage) *corruptionChecker {
+	return &corruptionChecker{
+		lg:     lg,
+		hasher: hasherAdapter{s, storage},
+	}
+}
+
+type hasherAdapter struct {
+	*EtcdServer
+	mvcc.HashStorage
+}
+
+func (h hasherAdapter) ReqTimeout() time.Duration {
+	return h.EtcdServer.Cfg.ReqTimeout()
+}
+
+func (h hasherAdapter) PeerHashByRev(rev int64) []*peerHashKVResp {
+	return h.EtcdServer.getPeerHashKVs(rev)
+}
+
+func (h hasherAdapter) TriggerCorruptAlarm(memberID types.ID) {
+	h.EtcdServer.triggerCorruptAlarm(memberID)
+}
+
+// InitialCheck compares initial hash values with its peers
+// before serving any peer/client traffic. Only mismatch when hashes
+// are different at requested revision, with same compact revision.
+func (cm *corruptionChecker) InitialCheck() error {
+	cm.lg.Info(
+		"starting initial corruption check",
+		zap.String("local-member-id", cm.hasher.MemberID().String()),
+		zap.Duration("timeout", cm.hasher.ReqTimeout()),
+	)
+
+	h, _, err := cm.hasher.HashByRev(0)
+	if err != nil {
+		return fmt.Errorf("%s failed to fetch hash (%w)", cm.hasher.MemberID(), err)
+	}
+	peers := cm.hasher.PeerHashByRev(h.Revision)
+	mismatch := 0
+	for _, p := range peers {
+		if p.resp != nil {
+			peerID := types.ID(p.resp.Header.MemberId)
+			fields := []zap.Field{
+				zap.String("local-member-id", cm.hasher.MemberID().String()),
+				zap.Int64("local-member-revision", h.Revision),
+				zap.Int64("local-member-compact-revision", h.CompactRevision),
+				zap.Uint32("local-member-hash", h.Hash),
+				zap.String("remote-peer-id", peerID.String()),
+				zap.Strings("remote-peer-endpoints", p.eps),
+				zap.Int64("remote-peer-revision", p.resp.Header.Revision),
+				zap.Int64("remote-peer-compact-revision", p.resp.CompactRevision),
+				zap.Uint32("remote-peer-hash", p.resp.Hash),
+			}
+
+			if h.Hash != p.resp.Hash {
+				if h.CompactRevision == p.resp.CompactRevision {
+					cm.lg.Warn("found different hash values from remote peer", fields...)
+					mismatch++
+				} else {
+					cm.lg.Warn("found different compact revision values from remote peer", fields...)
+				}
+			}
+
+			continue
+		}
+
+		if p.err != nil {
+			switch {
+			case errors.Is(p.err, rpctypes.ErrFutureRev):
+				cm.lg.Warn(
+					"cannot fetch hash from slow remote peer",
+					zap.String("local-member-id", cm.hasher.MemberID().String()),
+					zap.Int64("local-member-revision", h.Revision),
+					zap.Int64("local-member-compact-revision", h.CompactRevision),
+					zap.Uint32("local-member-hash", h.Hash),
+					zap.String("remote-peer-id", p.id.String()),
+					zap.Strings("remote-peer-endpoints", p.eps),
+					zap.Error(err),
+				)
+			case errors.Is(p.err, rpctypes.ErrCompacted):
+				cm.lg.Warn(
+					"cannot fetch hash from remote peer; local member is behind",
+					zap.String("local-member-id", cm.hasher.MemberID().String()),
+					zap.Int64("local-member-revision", h.Revision),
+					zap.Int64("local-member-compact-revision", h.CompactRevision),
+					zap.Uint32("local-member-hash", h.Hash),
+					zap.String("remote-peer-id", p.id.String()),
+					zap.Strings("remote-peer-endpoints", p.eps),
+					zap.Error(err),
+				)
+			case errors.Is(p.err, rpctypes.ErrClusterIDMismatch):
+				cm.lg.Warn(
+					"cluster ID mismatch",
+					zap.String("local-member-id", cm.hasher.MemberID().String()),
+					zap.Int64("local-member-revision", h.Revision),
+					zap.Int64("local-member-compact-revision", h.CompactRevision),
+					zap.Uint32("local-member-hash", h.Hash),
+					zap.String("remote-peer-id", p.id.String()),
+					zap.Strings("remote-peer-endpoints", p.eps),
+					zap.Error(err),
+				)
+			}
+		}
+	}
+	if mismatch > 0 {
+		return fmt.Errorf("%s found data inconsistency with peers", cm.hasher.MemberID())
+	}
+
+	cm.lg.Info(
+		"initial corruption checking passed; no corruption",
+		zap.String("local-member-id", cm.hasher.MemberID().String()),
+	)
+	return nil
+}
+
+func (cm *corruptionChecker) PeriodicCheck() error {
+	h, _, err := cm.hasher.HashByRev(0)
+	if err != nil {
+		return err
+	}
+	peers := cm.hasher.PeerHashByRev(h.Revision)
+
+	ctx, cancel := context.WithTimeout(context.Background(), cm.hasher.ReqTimeout())
+	err = cm.hasher.LinearizableReadNotify(ctx)
+	cancel()
+	if err != nil {
+		return err
+	}
+
+	h2, rev2, err := cm.hasher.HashByRev(0)
+	if err != nil {
+		return err
+	}
+
+	alarmed := false
+	mismatch := func(id types.ID) {
+		if alarmed {
+			return
+		}
+		alarmed = true
+		cm.hasher.TriggerCorruptAlarm(id)
+	}
+
+	if h2.Hash != h.Hash && h2.Revision == h.Revision && h.CompactRevision == h2.CompactRevision {
+		cm.lg.Warn(
+			"found hash mismatch",
+			zap.Int64("revision-1", h.Revision),
+			zap.Int64("compact-revision-1", h.CompactRevision),
+			zap.Uint32("hash-1", h.Hash),
+			zap.Int64("revision-2", h2.Revision),
+			zap.Int64("compact-revision-2", h2.CompactRevision),
+			zap.Uint32("hash-2", h2.Hash),
+		)
+		mismatch(cm.hasher.MemberID())
+	}
+
+	checkedCount := 0
+	for _, p := range peers {
+		if p.resp == nil {
+			continue
+		}
+		checkedCount++
+
+		// leader expects follower's latest revision less than or equal to leader's
+		if p.resp.Header.Revision > rev2 {
+			cm.lg.Warn(
+				"revision from follower must be less than or equal to leader's",
+				zap.Int64("leader-revision", rev2),
+				zap.Int64("follower-revision", p.resp.Header.Revision),
+				zap.String("follower-peer-id", p.id.String()),
+			)
+			mismatch(p.id)
+		}
+
+		// leader expects follower's latest compact revision less than or equal to leader's
+		if p.resp.CompactRevision > h2.CompactRevision {
+			cm.lg.Warn(
+				"compact revision from follower must be less than or equal to leader's",
+				zap.Int64("leader-compact-revision", h2.CompactRevision),
+				zap.Int64("follower-compact-revision", p.resp.CompactRevision),
+				zap.String("follower-peer-id", p.id.String()),
+			)
+			mismatch(p.id)
+		}
+
+		// follower's compact revision is leader's old one, then hashes must match
+		if p.resp.CompactRevision == h.CompactRevision && p.resp.Hash != h.Hash {
+			cm.lg.Warn(
+				"same compact revision then hashes must match",
+				zap.Int64("leader-compact-revision", h2.CompactRevision),
+				zap.Uint32("leader-hash", h.Hash),
+				zap.Int64("follower-compact-revision", p.resp.CompactRevision),
+				zap.Uint32("follower-hash", p.resp.Hash),
+				zap.String("follower-peer-id", p.id.String()),
+			)
+			mismatch(p.id)
+		}
+	}
+	cm.lg.Info("finished peer corruption check", zap.Int("number-of-peers-checked", checkedCount))
+	return nil
+}
+
+// CompactHashCheck is based on the fact that 'compactions' are coordinated
+// between raft members and performed at the same revision. For each compacted
+// revision there is KV store hash computed and saved for some time.
+//
+// This method communicates with peers to find a recent common revision across
+// members, and raises alarm if 2 or more members at the same compact revision
+// have different hashes.
+//
+// We might miss opportunity to perform the check if the compaction is still
+// ongoing on one of the members, or it was unresponsive. In such situation the
+// method still passes without raising alarm.
+func (cm *corruptionChecker) CompactHashCheck() {
+	cm.lg.Info("starting compact hash check",
+		zap.String("local-member-id", cm.hasher.MemberID().String()),
+		zap.Duration("timeout", cm.hasher.ReqTimeout()),
+	)
+	hashes := cm.uncheckedRevisions()
+	// Assume that revisions are ordered from largest to smallest
+	for i, hash := range hashes {
+		peers := cm.hasher.PeerHashByRev(hash.Revision)
+		if len(peers) == 0 {
+			continue
+		}
+		if cm.checkPeerHashes(hash, peers) {
+			cm.lg.Info("finished compaction hash check", zap.Int("number-of-hashes-checked", i+1))
+			return
+		}
+	}
+	cm.lg.Info("finished compaction hash check", zap.Int("number-of-hashes-checked", len(hashes)))
+}
+
+// check peers hash and raise alarms if detected corruption.
+// return a bool indicate whether to check next hash.
+//
+//	true: successfully checked hash on whole cluster or raised alarms, so no need to check next hash
+//	false: skipped some members, so need to check next hash
+func (cm *corruptionChecker) checkPeerHashes(leaderHash mvcc.KeyValueHash, peers []*peerHashKVResp) bool {
+	leaderID := cm.hasher.MemberID()
+	hash2members := map[uint32]types.IDSlice{leaderHash.Hash: {leaderID}}
+
+	peersChecked := 0
+	// group all peers by hash
+	for _, peer := range peers {
+		skipped := false
+		reason := ""
+
+		if peer.resp == nil {
+			skipped = true
+			reason = "no response"
+		} else if peer.resp.CompactRevision != leaderHash.CompactRevision {
+			skipped = true
+			reason = fmt.Sprintf("the peer's CompactRevision %d doesn't match leader's CompactRevision %d",
+				peer.resp.CompactRevision, leaderHash.CompactRevision)
+		}
+		if skipped {
+			cm.lg.Warn("Skipped peer's hash", zap.Int("number-of-peers", len(peers)),
+				zap.String("leader-id", leaderID.String()),
+				zap.String("peer-id", peer.id.String()),
+				zap.String("reason", reason))
+			continue
+		}
+
+		peersChecked++
+		if ids, ok := hash2members[peer.resp.Hash]; !ok {
+			hash2members[peer.resp.Hash] = []types.ID{peer.id}
+		} else {
+			ids = append(ids, peer.id)
+			hash2members[peer.resp.Hash] = ids
+		}
+	}
+
+	// All members have the same CompactRevision and Hash.
+	if len(hash2members) == 1 {
+		return cm.handleConsistentHash(leaderHash, peersChecked, len(peers))
+	}
+
+	// Detected hashes mismatch
+	// The first step is to figure out the majority with the same hash.
+	memberCnt := len(peers) + 1
+	quorum := memberCnt/2 + 1
+	quorumExist := false
+	for k, v := range hash2members {
+		if len(v) >= quorum {
+			quorumExist = true
+			// remove the majority, and we might raise alarms for the left members.
+			delete(hash2members, k)
+			break
+		}
+	}
+
+	if !quorumExist {
+		// If quorum doesn't exist, we don't know which members data are
+		// corrupted. In such situation, we intentionally set the memberID
+		// as 0, it means it affects the whole cluster.
+		cm.lg.Error("Detected compaction hash mismatch but cannot identify the corrupted members, so intentionally set the memberID as 0",
+			zap.String("leader-id", leaderID.String()),
+			zap.Int64("leader-revision", leaderHash.Revision),
+			zap.Int64("leader-compact-revision", leaderHash.CompactRevision),
+			zap.Uint32("leader-hash", leaderHash.Hash),
+		)
+		cm.hasher.TriggerCorruptAlarm(0)
+	}
+
+	// Raise alarm for the left members if the quorum is present.
+	// But we should always generate error log for debugging.
+	for k, v := range hash2members {
+		if quorumExist {
+			for _, pid := range v {
+				cm.hasher.TriggerCorruptAlarm(pid)
+			}
+		}
+
+		cm.lg.Error("Detected compaction hash mismatch",
+			zap.String("leader-id", leaderID.String()),
+			zap.Int64("leader-revision", leaderHash.Revision),
+			zap.Int64("leader-compact-revision", leaderHash.CompactRevision),
+			zap.Uint32("leader-hash", leaderHash.Hash),
+			zap.Uint32("peer-hash", k),
+			zap.String("peer-ids", v.String()),
+			zap.Bool("quorum-exist", quorumExist),
+		)
+	}
+
+	return true
+}
+
+func (cm *corruptionChecker) handleConsistentHash(hash mvcc.KeyValueHash, peersChecked, peerCnt int) bool {
+	if peersChecked == peerCnt {
+		cm.lg.Info("successfully checked hash on whole cluster",
+			zap.Int("number-of-peers-checked", peersChecked),
+			zap.Int64("revision", hash.Revision),
+			zap.Int64("compactRevision", hash.CompactRevision),
+		)
+		cm.mux.Lock()
+		if hash.Revision > cm.latestRevisionChecked {
+			cm.latestRevisionChecked = hash.Revision
+		}
+		cm.mux.Unlock()
+		return true
+	}
+	cm.lg.Warn("skipped revision in compaction hash check; was not able to check all peers",
+		zap.Int("number-of-peers-checked", peersChecked),
+		zap.Int("number-of-peers", peerCnt),
+		zap.Int64("revision", hash.Revision),
+		zap.Int64("compactRevision", hash.CompactRevision),
+	)
+	// The only case which needs to check next hash
+	return false
+}
+
+func (cm *corruptionChecker) uncheckedRevisions() []mvcc.KeyValueHash {
+	cm.mux.RLock()
+	lastRevisionChecked := cm.latestRevisionChecked
+	cm.mux.RUnlock()
+
+	hashes := cm.hasher.Hashes()
+	// Sort in descending order
+	sort.Slice(hashes, func(i, j int) bool {
+		return hashes[i].Revision > hashes[j].Revision
+	})
+	for i, hash := range hashes {
+		if hash.Revision <= lastRevisionChecked {
+			return hashes[:i]
+		}
+	}
+	return hashes
+}
+
+func (s *EtcdServer) triggerCorruptAlarm(id types.ID) {
+	a := &pb.AlarmRequest{
+		MemberID: uint64(id),
+		Action:   pb.AlarmRequest_ACTIVATE,
+		Alarm:    pb.AlarmType_CORRUPT,
+	}
+	s.GoAttach(func() {
+		s.raftRequest(s.ctx, pb.InternalRaftRequest{Alarm: a})
+	})
+}
+
+type peerInfo struct {
+	id  types.ID
+	eps []string
+}
+
+type peerHashKVResp struct {
+	peerInfo
+	resp *pb.HashKVResponse
+	err  error
+}
+
+func (s *EtcdServer) getPeerHashKVs(rev int64) []*peerHashKVResp {
+	// TODO: handle the case when "s.cluster.Members" have not
+	// been populated (e.g. no snapshot to load from disk)
+	members := s.cluster.Members()
+	peers := make([]peerInfo, 0, len(members))
+	for _, m := range members {
+		if m.ID == s.MemberID() {
+			continue
+		}
+		peers = append(peers, peerInfo{id: m.ID, eps: m.PeerURLs})
+	}
+
+	lg := s.Logger()
+
+	cc := &http.Client{
+		Transport: s.peerRt,
+		CheckRedirect: func(req *http.Request, via []*http.Request) error {
+			return http.ErrUseLastResponse
+		},
+	}
+	var resps []*peerHashKVResp
+	for _, p := range peers {
+		if len(p.eps) == 0 {
+			continue
+		}
+
+		respsLen := len(resps)
+		var lastErr error
+		for _, ep := range p.eps {
+			var resp *pb.HashKVResponse
+
+			ctx, cancel := context.WithTimeout(context.Background(), s.Cfg.ReqTimeout())
+			resp, lastErr = HashByRev(ctx, s.cluster.ID(), cc, ep, rev)
+			cancel()
+			if lastErr == nil {
+				resps = append(resps, &peerHashKVResp{peerInfo: p, resp: resp, err: nil})
+				break
+			}
+			lg.Warn(
+				"failed hash kv request",
+				zap.String("local-member-id", s.MemberID().String()),
+				zap.Int64("requested-revision", rev),
+				zap.String("remote-peer-endpoint", ep),
+				zap.Error(lastErr),
+			)
+		}
+
+		// failed to get hashKV from all endpoints of this peer
+		if respsLen == len(resps) {
+			resps = append(resps, &peerHashKVResp{peerInfo: p, resp: nil, err: lastErr})
+		}
+	}
+	return resps
+}
+
+const PeerHashKVPath = "/members/hashkv"
+
+type hashKVHandler struct {
+	lg     *zap.Logger
+	server *EtcdServer
+}
+
+func (s *EtcdServer) HashKVHandler() http.Handler {
+	return &hashKVHandler{lg: s.Logger(), server: s}
+}
+
+func (h *hashKVHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodGet {
+		w.Header().Set("Allow", http.MethodGet)
+		http.Error(w, "Method Not Allowed", http.StatusMethodNotAllowed)
+		return
+	}
+	if r.URL.Path != PeerHashKVPath {
+		http.Error(w, "bad path", http.StatusBadRequest)
+		return
+	}
+	if gcid := r.Header.Get("X-Etcd-Cluster-ID"); gcid != "" && gcid != h.server.cluster.ID().String() {
+		http.Error(w, rafthttp.ErrClusterIDMismatch.Error(), http.StatusPreconditionFailed)
+		return
+	}
+
+	defer r.Body.Close()
+	b, err := io.ReadAll(r.Body)
+	if err != nil {
+		http.Error(w, "error reading body", http.StatusBadRequest)
+		return
+	}
+
+	req := &pb.HashKVRequest{}
+	if err = json.Unmarshal(b, req); err != nil {
+		h.lg.Warn("failed to unmarshal request", zap.Error(err))
+		http.Error(w, "error unmarshalling request", http.StatusBadRequest)
+		return
+	}
+	hash, rev, err := h.server.KV().HashStorage().HashByRev(req.Revision)
+	if err != nil {
+		h.lg.Warn(
+			"failed to get hashKV",
+			zap.Int64("requested-revision", req.Revision),
+			zap.Error(err),
+		)
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+	resp := &pb.HashKVResponse{
+		Header:          &pb.ResponseHeader{Revision: rev},
+		Hash:            hash.Hash,
+		CompactRevision: hash.CompactRevision,
+		HashRevision:    hash.Revision,
+	}
+	respBytes, err := json.Marshal(resp)
+	if err != nil {
+		h.lg.Warn("failed to marshal hashKV response", zap.Error(err))
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	w.Header().Set("X-Etcd-Cluster-ID", h.server.Cluster().ID().String())
+	w.Header().Set("Content-Type", "application/json")
+	w.Write(respBytes)
+}
+
+// HashByRev fetch hash of kv store at the given rev via http call to the given url
+func HashByRev(ctx context.Context, cid types.ID, cc *http.Client, url string, rev int64) (*pb.HashKVResponse, error) {
+	hashReq := &pb.HashKVRequest{Revision: rev}
+	hashReqBytes, err := json.Marshal(hashReq)
+	if err != nil {
+		return nil, err
+	}
+	requestURL := url + PeerHashKVPath
+	req, err := http.NewRequest(http.MethodGet, requestURL, bytes.NewReader(hashReqBytes))
+	if err != nil {
+		return nil, err
+	}
+	req = req.WithContext(ctx)
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("X-Etcd-Cluster-ID", cid.String())
+	req.Cancel = ctx.Done()
+
+	resp, err := cc.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+	b, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	if resp.StatusCode == http.StatusBadRequest {
+		if strings.Contains(string(b), mvcc.ErrCompacted.Error()) {
+			return nil, rpctypes.ErrCompacted
+		}
+		if strings.Contains(string(b), mvcc.ErrFutureRev.Error()) {
+			return nil, rpctypes.ErrFutureRev
+		}
+	} else if resp.StatusCode == http.StatusPreconditionFailed {
+		if strings.Contains(string(b), rafthttp.ErrClusterIDMismatch.Error()) {
+			return nil, rpctypes.ErrClusterIDMismatch
+		}
+	}
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("unknown error: %s", b)
+	}
+
+	hashResp := &pb.HashKVResponse{}
+	if err := json.Unmarshal(b, hashResp); err != nil {
+		return nil, err
+	}
+	return hashResp, nil
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/doc.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/doc.go
new file mode 100644
index 0000000..b195d2d
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/doc.go
@@ -0,0 +1,16 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package etcdserver defines how etcd servers interact and store their states.
+package etcdserver
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/errors/errors.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/errors/errors.go
new file mode 100644
index 0000000..8de698a
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/errors/errors.go
@@ -0,0 +1,54 @@
+// Copyright 2022 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package errors
+
+import (
+	"errors"
+	"fmt"
+)
+
+var (
+	ErrUnknownMethod               = errors.New("etcdserver: unknown method")
+	ErrStopped                     = errors.New("etcdserver: server stopped")
+	ErrCanceled                    = errors.New("etcdserver: request cancelled")
+	ErrTimeout                     = errors.New("etcdserver: request timed out")
+	ErrTimeoutDueToLeaderFail      = errors.New("etcdserver: request timed out, possibly due to previous leader failure")
+	ErrTimeoutDueToConnectionLost  = errors.New("etcdserver: request timed out, possibly due to connection lost")
+	ErrTimeoutLeaderTransfer       = errors.New("etcdserver: request timed out, leader transfer took too long")
+	ErrTimeoutWaitAppliedIndex     = errors.New("etcdserver: request timed out, waiting for the applied index took too long")
+	ErrLeaderChanged               = errors.New("etcdserver: leader changed")
+	ErrNotEnoughStartedMembers     = errors.New("etcdserver: re-configuration failed due to not enough started members")
+	ErrLearnerNotReady             = errors.New("etcdserver: can only promote a learner member which is in sync with leader")
+	ErrNoLeader                    = errors.New("etcdserver: no leader")
+	ErrNotLeader                   = errors.New("etcdserver: not leader")
+	ErrRequestTooLarge             = errors.New("etcdserver: request is too large")
+	ErrNoSpace                     = errors.New("etcdserver: no space")
+	ErrTooManyRequests             = errors.New("etcdserver: too many requests")
+	ErrUnhealthy                   = errors.New("etcdserver: unhealthy cluster")
+	ErrCorrupt                     = errors.New("etcdserver: corrupt cluster")
+	ErrBadLeaderTransferee         = errors.New("etcdserver: bad leader transferee")
+	ErrClusterVersionUnavailable   = errors.New("etcdserver: cluster version not found during downgrade")
+	ErrWrongDowngradeVersionFormat = errors.New("etcdserver: wrong downgrade target version format")
+	ErrKeyNotFound                 = errors.New("etcdserver: key not found")
+)
+
+type DiscoveryError struct {
+	Op  string
+	Err error
+}
+
+func (e DiscoveryError) Error() string {
+	return fmt.Sprintf("failed to %s discovery cluster (%v)", e.Op, e.Err)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/metrics.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/metrics.go
new file mode 100644
index 0000000..7176d30
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/metrics.go
@@ -0,0 +1,224 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package etcdserver
+
+import (
+	goruntime "runtime"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/api/v3/version"
+	"go.etcd.io/etcd/pkg/v3/runtime"
+)
+
+var (
+	hasLeader = prometheus.NewGauge(prometheus.GaugeOpts{
+		Namespace: "etcd",
+		Subsystem: "server",
+		Name:      "has_leader",
+		Help:      "Whether or not a leader exists. 1 is existence, 0 is not.",
+	})
+	isLeader = prometheus.NewGauge(prometheus.GaugeOpts{
+		Namespace: "etcd",
+		Subsystem: "server",
+		Name:      "is_leader",
+		Help:      "Whether or not this member is a leader. 1 if is, 0 otherwise.",
+	})
+	leaderChanges = prometheus.NewCounter(prometheus.CounterOpts{
+		Namespace: "etcd",
+		Subsystem: "server",
+		Name:      "leader_changes_seen_total",
+		Help:      "The number of leader changes seen.",
+	})
+	learnerPromoteFailed = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: "etcd",
+			Subsystem: "server",
+			Name:      "learner_promote_failures",
+			Help:      "The total number of failed learner promotions (likely learner not ready) while this member is leader.",
+		},
+		[]string{"Reason"},
+	)
+	learnerPromoteSucceed = prometheus.NewCounter(prometheus.CounterOpts{
+		Namespace: "etcd",
+		Subsystem: "server",
+		Name:      "learner_promote_successes",
+		Help:      "The total number of successful learner promotions while this member is leader.",
+	})
+	heartbeatSendFailures = prometheus.NewCounter(prometheus.CounterOpts{
+		Namespace: "etcd",
+		Subsystem: "server",
+		Name:      "heartbeat_send_failures_total",
+		Help:      "The total number of leader heartbeat send failures (likely overloaded from slow disk).",
+	})
+	applySnapshotInProgress = prometheus.NewGauge(prometheus.GaugeOpts{
+		Namespace: "etcd",
+		Subsystem: "server",
+		Name:      "snapshot_apply_in_progress_total",
+		Help:      "1 if the server is applying the incoming snapshot. 0 if none.",
+	})
+	proposalsCommitted = prometheus.NewGauge(prometheus.GaugeOpts{
+		Namespace: "etcd",
+		Subsystem: "server",
+		Name:      "proposals_committed_total",
+		Help:      "The total number of consensus proposals committed.",
+	})
+	proposalsApplied = prometheus.NewGauge(prometheus.GaugeOpts{
+		Namespace: "etcd",
+		Subsystem: "server",
+		Name:      "proposals_applied_total",
+		Help:      "The total number of consensus proposals applied.",
+	})
+	proposalsPending = prometheus.NewGauge(prometheus.GaugeOpts{
+		Namespace: "etcd",
+		Subsystem: "server",
+		Name:      "proposals_pending",
+		Help:      "The current number of pending proposals to commit.",
+	})
+	proposalsFailed = prometheus.NewCounter(prometheus.CounterOpts{
+		Namespace: "etcd",
+		Subsystem: "server",
+		Name:      "proposals_failed_total",
+		Help:      "The total number of failed proposals seen.",
+	})
+	slowReadIndex = prometheus.NewCounter(prometheus.CounterOpts{
+		Namespace: "etcd",
+		Subsystem: "server",
+		Name:      "slow_read_indexes_total",
+		Help:      "The total number of pending read indexes not in sync with leader's or timed out read index requests.",
+	})
+	readIndexFailed = prometheus.NewCounter(prometheus.CounterOpts{
+		Namespace: "etcd",
+		Subsystem: "server",
+		Name:      "read_indexes_failed_total",
+		Help:      "The total number of failed read indexes seen.",
+	})
+	leaseExpired = prometheus.NewCounter(prometheus.CounterOpts{
+		Namespace: "etcd_debugging",
+		Subsystem: "server",
+		Name:      "lease_expired_total",
+		Help:      "The total number of expired leases.",
+	})
+	currentVersion = prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Namespace: "etcd",
+			Subsystem: "server",
+			Name:      "version",
+			Help:      "Which version is running. 1 for 'server_version' label with current version.",
+		},
+		[]string{"server_version"},
+	)
+	currentGoVersion = prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Namespace: "etcd",
+			Subsystem: "server",
+			Name:      "go_version",
+			Help:      "Which Go version server is running with. 1 for 'server_go_version' label with current version.",
+		},
+		[]string{"server_go_version"},
+	)
+	serverID = prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Namespace: "etcd",
+			Subsystem: "server",
+			Name:      "id",
+			Help:      "Server or member ID in hexadecimal format. 1 for 'server_id' label with current ID.",
+		},
+		[]string{"server_id"},
+	)
+	serverFeatureEnabled = prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Name: "etcd_server_feature_enabled",
+			Help: "Whether or not a feature is enabled. 1 is enabled, 0 is not.",
+		},
+		[]string{"name", "stage"},
+	)
+	fdUsed = prometheus.NewGauge(prometheus.GaugeOpts{
+		Namespace: "os",
+		Subsystem: "fd",
+		Name:      "used",
+		Help:      "The number of used file descriptors.",
+	})
+	fdLimit = prometheus.NewGauge(prometheus.GaugeOpts{
+		Namespace: "os",
+		Subsystem: "fd",
+		Name:      "limit",
+		Help:      "The file descriptor limit.",
+	})
+)
+
+func init() {
+	prometheus.MustRegister(hasLeader)
+	prometheus.MustRegister(isLeader)
+	prometheus.MustRegister(leaderChanges)
+	prometheus.MustRegister(heartbeatSendFailures)
+	prometheus.MustRegister(applySnapshotInProgress)
+	prometheus.MustRegister(proposalsCommitted)
+	prometheus.MustRegister(proposalsApplied)
+	prometheus.MustRegister(proposalsPending)
+	prometheus.MustRegister(proposalsFailed)
+	prometheus.MustRegister(slowReadIndex)
+	prometheus.MustRegister(readIndexFailed)
+	prometheus.MustRegister(leaseExpired)
+	prometheus.MustRegister(currentVersion)
+	prometheus.MustRegister(currentGoVersion)
+	prometheus.MustRegister(serverID)
+	prometheus.MustRegister(serverFeatureEnabled)
+	prometheus.MustRegister(learnerPromoteSucceed)
+	prometheus.MustRegister(learnerPromoteFailed)
+	prometheus.MustRegister(fdUsed)
+	prometheus.MustRegister(fdLimit)
+
+	currentVersion.With(prometheus.Labels{
+		"server_version": version.Version,
+	}).Set(1)
+	currentGoVersion.With(prometheus.Labels{
+		"server_go_version": goruntime.Version(),
+	}).Set(1)
+}
+
+func monitorFileDescriptor(lg *zap.Logger, done <-chan struct{}) {
+	// This ticker will check File Descriptor Requirements ,and count all fds in used.
+	// And recorded some logs when in used >= limit/5*4. Just recorded message.
+	// If fds was more than 10K,It's low performance due to FDUsage() works.
+	// So need to increase it.
+	// See https://github.com/etcd-io/etcd/issues/11969 for more detail.
+	ticker := time.NewTicker(10 * time.Minute)
+	defer ticker.Stop()
+	for {
+		used, err := runtime.FDUsage()
+		if err != nil {
+			lg.Warn("failed to get file descriptor usage", zap.Error(err))
+			return
+		}
+		fdUsed.Set(float64(used))
+		limit, err := runtime.FDLimit()
+		if err != nil {
+			lg.Warn("failed to get file descriptor limit", zap.Error(err))
+			return
+		}
+		fdLimit.Set(float64(limit))
+		if used >= limit/5*4 {
+			lg.Warn("80% of file descriptors are used", zap.Uint64("used", used), zap.Uint64("limit", limit))
+		}
+		select {
+		case <-ticker.C:
+		case <-done:
+			return
+		}
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/raft.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/raft.go
new file mode 100644
index 0000000..fd4b5da
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/raft.go
@@ -0,0 +1,446 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package etcdserver
+
+import (
+	"expvar"
+	"fmt"
+	"log"
+	"sync"
+	"time"
+
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/client/pkg/v3/logutil"
+	"go.etcd.io/etcd/pkg/v3/contention"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp"
+	serverstorage "go.etcd.io/etcd/server/v3/storage"
+	"go.etcd.io/raft/v3"
+	"go.etcd.io/raft/v3/raftpb"
+)
+
+const (
+	// The max throughput of etcd will not exceed 100MB/s (100K * 1KB value).
+	// Assuming the RTT is around 10ms, 1MB max size is large enough.
+	maxSizePerMsg = 1 * 1024 * 1024
+	// Never overflow the rafthttp buffer, which is 4096.
+	// TODO: a better const?
+	maxInflightMsgs = 4096 / 8
+)
+
+var (
+	// protects raftStatus
+	raftStatusMu sync.Mutex
+	// indirection for expvar func interface
+	// expvar panics when publishing duplicate name
+	// expvar does not support remove a registered name
+	// so only register a func that calls raftStatus
+	// and change raftStatus as we need.
+	raftStatus func() raft.Status
+)
+
+func init() {
+	expvar.Publish("raft.status", expvar.Func(func() any {
+		raftStatusMu.Lock()
+		defer raftStatusMu.Unlock()
+		if raftStatus == nil {
+			return nil
+		}
+		return raftStatus()
+	}))
+}
+
+// toApply contains entries, snapshot to be applied. Once
+// an toApply is consumed, the entries will be persisted to
+// raft storage concurrently; the application must read
+// notifyc before assuming the raft messages are stable.
+type toApply struct {
+	entries  []raftpb.Entry
+	snapshot raftpb.Snapshot
+	// notifyc synchronizes etcd server applies with the raft node
+	notifyc chan struct{}
+	// raftAdvancedC notifies EtcdServer.apply that
+	// 'raftLog.applied' has advanced by r.Advance
+	// it should be used only when entries contain raftpb.EntryConfChange
+	raftAdvancedC <-chan struct{}
+}
+
+type raftNode struct {
+	lg *zap.Logger
+
+	tickMu *sync.RWMutex
+	// timestamp of the latest tick
+	latestTickTs time.Time
+	raftNodeConfig
+
+	// a chan to send/receive snapshot
+	msgSnapC chan raftpb.Message
+
+	// a chan to send out apply
+	applyc chan toApply
+
+	// a chan to send out readState
+	readStateC chan raft.ReadState
+
+	// utility
+	ticker *time.Ticker
+	// contention detectors for raft heartbeat message
+	td *contention.TimeoutDetector
+
+	stopped chan struct{}
+	done    chan struct{}
+}
+
+type raftNodeConfig struct {
+	lg *zap.Logger
+
+	// to check if msg receiver is removed from cluster
+	isIDRemoved func(id uint64) bool
+	raft.Node
+	raftStorage *raft.MemoryStorage
+	storage     serverstorage.Storage
+	heartbeat   time.Duration // for logging
+	// transport specifies the transport to send and receive msgs to members.
+	// Sending messages MUST NOT block. It is okay to drop messages, since
+	// clients should timeout and reissue their messages.
+	// If transport is nil, server will panic.
+	transport rafthttp.Transporter
+}
+
+func newRaftNode(cfg raftNodeConfig) *raftNode {
+	var lg raft.Logger
+	if cfg.lg != nil {
+		lg = NewRaftLoggerZap(cfg.lg)
+	} else {
+		lcfg := logutil.DefaultZapLoggerConfig
+		var err error
+		lg, err = NewRaftLogger(&lcfg)
+		if err != nil {
+			log.Fatalf("cannot create raft logger %v", err)
+		}
+	}
+	raft.SetLogger(lg)
+	r := &raftNode{
+		lg:             cfg.lg,
+		tickMu:         new(sync.RWMutex),
+		raftNodeConfig: cfg,
+		latestTickTs:   time.Now(),
+		// set up contention detectors for raft heartbeat message.
+		// expect to send a heartbeat within 2 heartbeat intervals.
+		td:         contention.NewTimeoutDetector(2 * cfg.heartbeat),
+		readStateC: make(chan raft.ReadState, 1),
+		msgSnapC:   make(chan raftpb.Message, maxInFlightMsgSnap),
+		applyc:     make(chan toApply),
+		stopped:    make(chan struct{}),
+		done:       make(chan struct{}),
+	}
+	if r.heartbeat == 0 {
+		r.ticker = &time.Ticker{}
+	} else {
+		r.ticker = time.NewTicker(r.heartbeat)
+	}
+	return r
+}
+
+// raft.Node does not have locks in Raft package
+func (r *raftNode) tick() {
+	r.tickMu.Lock()
+	r.Tick()
+	r.latestTickTs = time.Now()
+	r.tickMu.Unlock()
+}
+
+func (r *raftNode) getLatestTickTs() time.Time {
+	r.tickMu.RLock()
+	defer r.tickMu.RUnlock()
+	return r.latestTickTs
+}
+
+// start prepares and starts raftNode in a new goroutine. It is no longer safe
+// to modify the fields after it has been started.
+func (r *raftNode) start(rh *raftReadyHandler) {
+	internalTimeout := time.Second
+
+	go func() {
+		defer r.onStop()
+		islead := false
+
+		for {
+			select {
+			case <-r.ticker.C:
+				r.tick()
+			case rd := <-r.Ready():
+				if rd.SoftState != nil {
+					newLeader := rd.SoftState.Lead != raft.None && rh.getLead() != rd.SoftState.Lead
+					if newLeader {
+						leaderChanges.Inc()
+					}
+
+					if rd.SoftState.Lead == raft.None {
+						hasLeader.Set(0)
+					} else {
+						hasLeader.Set(1)
+					}
+
+					rh.updateLead(rd.SoftState.Lead)
+					islead = rd.RaftState == raft.StateLeader
+					if islead {
+						isLeader.Set(1)
+					} else {
+						isLeader.Set(0)
+					}
+					rh.updateLeadership(newLeader)
+					r.td.Reset()
+				}
+
+				if len(rd.ReadStates) != 0 {
+					select {
+					case r.readStateC <- rd.ReadStates[len(rd.ReadStates)-1]:
+					case <-time.After(internalTimeout):
+						r.lg.Warn("timed out sending read state", zap.Duration("timeout", internalTimeout))
+					case <-r.stopped:
+						return
+					}
+				}
+
+				notifyc := make(chan struct{}, 1)
+				raftAdvancedC := make(chan struct{}, 1)
+				ap := toApply{
+					entries:       rd.CommittedEntries,
+					snapshot:      rd.Snapshot,
+					notifyc:       notifyc,
+					raftAdvancedC: raftAdvancedC,
+				}
+
+				updateCommittedIndex(&ap, rh)
+
+				select {
+				case r.applyc <- ap:
+				case <-r.stopped:
+					return
+				}
+
+				// the leader can write to its disk in parallel with replicating to the followers and then
+				// writing to their disks.
+				// For more details, check raft thesis 10.2.1
+				if islead {
+					// gofail: var raftBeforeLeaderSend struct{}
+					r.transport.Send(r.processMessages(rd.Messages))
+				}
+
+				// Must save the snapshot file and WAL snapshot entry before saving any other entries or hardstate to
+				// ensure that recovery after a snapshot restore is possible.
+				if !raft.IsEmptySnap(rd.Snapshot) {
+					// gofail: var raftBeforeSaveSnap struct{}
+					if err := r.storage.SaveSnap(rd.Snapshot); err != nil {
+						r.lg.Fatal("failed to save Raft snapshot", zap.Error(err))
+					}
+					// gofail: var raftAfterSaveSnap struct{}
+				}
+
+				// gofail: var raftBeforeSave struct{}
+				if err := r.storage.Save(rd.HardState, rd.Entries); err != nil {
+					r.lg.Fatal("failed to save Raft hard state and entries", zap.Error(err))
+				}
+				if !raft.IsEmptyHardState(rd.HardState) {
+					proposalsCommitted.Set(float64(rd.HardState.Commit))
+				}
+				// gofail: var raftAfterSave struct{}
+
+				if !raft.IsEmptySnap(rd.Snapshot) {
+					// Force WAL to fsync its hard state before Release() releases
+					// old data from the WAL. Otherwise could get an error like:
+					// panic: tocommit(107) is out of range [lastIndex(84)]. Was the raft log corrupted, truncated, or lost?
+					// See https://github.com/etcd-io/etcd/issues/10219 for more details.
+					if err := r.storage.Sync(); err != nil {
+						r.lg.Fatal("failed to sync Raft snapshot", zap.Error(err))
+					}
+
+					// etcdserver now claim the snapshot has been persisted onto the disk
+					notifyc <- struct{}{}
+
+					// gofail: var raftBeforeApplySnap struct{}
+					r.raftStorage.ApplySnapshot(rd.Snapshot)
+					r.lg.Info("applied incoming Raft snapshot", zap.Uint64("snapshot-index", rd.Snapshot.Metadata.Index))
+					// gofail: var raftAfterApplySnap struct{}
+
+					if err := r.storage.Release(rd.Snapshot); err != nil {
+						r.lg.Fatal("failed to release Raft wal", zap.Error(err))
+					}
+					// gofail: var raftAfterWALRelease struct{}
+				}
+
+				r.raftStorage.Append(rd.Entries)
+
+				confChanged := false
+				for _, ent := range rd.CommittedEntries {
+					if ent.Type == raftpb.EntryConfChange {
+						confChanged = true
+						break
+					}
+				}
+
+				if !islead {
+					// finish processing incoming messages before we signal notifyc chan
+					msgs := r.processMessages(rd.Messages)
+
+					// now unblocks 'applyAll' that waits on Raft log disk writes before triggering snapshots
+					notifyc <- struct{}{}
+
+					// Candidate or follower needs to wait for all pending configuration
+					// changes to be applied before sending messages.
+					// Otherwise we might incorrectly count votes (e.g. votes from removed members).
+					// Also slow machine's follower raft-layer could proceed to become the leader
+					// on its own single-node cluster, before toApply-layer applies the config change.
+					// We simply wait for ALL pending entries to be applied for now.
+					// We might improve this later on if it causes unnecessary long blocking issues.
+
+					if confChanged {
+						// blocks until 'applyAll' calls 'applyWait.Trigger'
+						// to be in sync with scheduled config-change job
+						// (assume notifyc has cap of 1)
+						select {
+						case notifyc <- struct{}{}:
+						case <-r.stopped:
+							return
+						}
+					}
+
+					// gofail: var raftBeforeFollowerSend struct{}
+					r.transport.Send(msgs)
+				} else {
+					// leader already processed 'MsgSnap' and signaled
+					notifyc <- struct{}{}
+				}
+
+				// gofail: var raftBeforeAdvance struct{}
+				r.Advance()
+
+				if confChanged {
+					// notify etcdserver that raft has already been notified or advanced.
+					raftAdvancedC <- struct{}{}
+				}
+			case <-r.stopped:
+				return
+			}
+		}
+	}()
+}
+
+func updateCommittedIndex(ap *toApply, rh *raftReadyHandler) {
+	var ci uint64
+	if len(ap.entries) != 0 {
+		ci = ap.entries[len(ap.entries)-1].Index
+	}
+	if ap.snapshot.Metadata.Index > ci {
+		ci = ap.snapshot.Metadata.Index
+	}
+	if ci != 0 {
+		rh.updateCommittedIndex(ci)
+	}
+}
+
+func (r *raftNode) processMessages(ms []raftpb.Message) []raftpb.Message {
+	sentAppResp := false
+	for i := len(ms) - 1; i >= 0; i-- {
+		if r.isIDRemoved(ms[i].To) {
+			ms[i].To = 0
+			continue
+		}
+
+		if ms[i].Type == raftpb.MsgAppResp {
+			if sentAppResp {
+				ms[i].To = 0
+			} else {
+				sentAppResp = true
+			}
+		}
+
+		if ms[i].Type == raftpb.MsgSnap {
+			// There are two separate data store: the store for v2, and the KV for v3.
+			// The msgSnap only contains the most recent snapshot of store without KV.
+			// So we need to redirect the msgSnap to etcd server main loop for merging in the
+			// current store snapshot and KV snapshot.
+			select {
+			case r.msgSnapC <- ms[i]:
+			default:
+				// drop msgSnap if the inflight chan if full.
+			}
+			ms[i].To = 0
+		}
+		if ms[i].Type == raftpb.MsgHeartbeat {
+			ok, exceed := r.td.Observe(ms[i].To)
+			if !ok {
+				// TODO: limit request rate.
+				r.lg.Warn(
+					"leader failed to send out heartbeat on time; took too long, leader is overloaded likely from slow disk",
+					zap.String("to", fmt.Sprintf("%x", ms[i].To)),
+					zap.Duration("heartbeat-interval", r.heartbeat),
+					zap.Duration("expected-duration", 2*r.heartbeat),
+					zap.Duration("exceeded-duration", exceed),
+				)
+				heartbeatSendFailures.Inc()
+			}
+		}
+	}
+	return ms
+}
+
+func (r *raftNode) apply() chan toApply {
+	return r.applyc
+}
+
+func (r *raftNode) stop() {
+	select {
+	case r.stopped <- struct{}{}:
+		// Not already stopped, so trigger it
+	case <-r.done:
+		// Has already been stopped - no need to do anything
+		return
+	}
+	// Block until the stop has been acknowledged by start()
+	<-r.done
+}
+
+func (r *raftNode) onStop() {
+	r.Stop()
+	r.ticker.Stop()
+	r.transport.Stop()
+	if err := r.storage.Close(); err != nil {
+		r.lg.Panic("failed to close Raft storage", zap.Error(err))
+	}
+	close(r.done)
+}
+
+// for testing
+func (r *raftNode) pauseSending() {
+	p := r.transport.(rafthttp.Pausable)
+	p.Pause()
+}
+
+func (r *raftNode) resumeSending() {
+	p := r.transport.(rafthttp.Pausable)
+	p.Resume()
+}
+
+// advanceTicks advances ticks of Raft node.
+// This can be used for fast-forwarding election
+// ticks in multi data-center deployments, thus
+// speeding up election process.
+func (r *raftNode) advanceTicks(ticks int) {
+	for i := 0; i < ticks; i++ {
+		r.tick()
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/server.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/server.go
new file mode 100644
index 0000000..0eb16b7
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/server.go
@@ -0,0 +1,2592 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package etcdserver
+
+import (
+	"context"
+	"encoding/json"
+	errorspkg "errors"
+	"expvar"
+	"fmt"
+	"math"
+	"net/http"
+	"path"
+	"reflect"
+	"regexp"
+	"strconv"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"github.com/coreos/go-semver/semver"
+	humanize "github.com/dustin/go-humanize"
+	"github.com/prometheus/client_golang/prometheus"
+	"go.uber.org/zap"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/api/v3/membershippb"
+	"go.etcd.io/etcd/api/v3/version"
+	"go.etcd.io/etcd/client/pkg/v3/fileutil"
+	"go.etcd.io/etcd/client/pkg/v3/types"
+	"go.etcd.io/etcd/client/pkg/v3/verify"
+	"go.etcd.io/etcd/pkg/v3/featuregate"
+	"go.etcd.io/etcd/pkg/v3/idutil"
+	"go.etcd.io/etcd/pkg/v3/notify"
+	"go.etcd.io/etcd/pkg/v3/pbutil"
+	"go.etcd.io/etcd/pkg/v3/runtime"
+	"go.etcd.io/etcd/pkg/v3/schedule"
+	"go.etcd.io/etcd/pkg/v3/traceutil"
+	"go.etcd.io/etcd/pkg/v3/wait"
+	"go.etcd.io/etcd/server/v3/auth"
+	"go.etcd.io/etcd/server/v3/config"
+	"go.etcd.io/etcd/server/v3/etcdserver/api"
+	httptypes "go.etcd.io/etcd/server/v3/etcdserver/api/etcdhttp/types"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/membership"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/snap"
+	stats "go.etcd.io/etcd/server/v3/etcdserver/api/v2stats"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v2store"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v3alarm"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v3compactor"
+	"go.etcd.io/etcd/server/v3/etcdserver/apply"
+	"go.etcd.io/etcd/server/v3/etcdserver/cindex"
+	"go.etcd.io/etcd/server/v3/etcdserver/errors"
+	"go.etcd.io/etcd/server/v3/etcdserver/txn"
+	serverversion "go.etcd.io/etcd/server/v3/etcdserver/version"
+	"go.etcd.io/etcd/server/v3/features"
+	"go.etcd.io/etcd/server/v3/lease"
+	"go.etcd.io/etcd/server/v3/lease/leasehttp"
+	serverstorage "go.etcd.io/etcd/server/v3/storage"
+	"go.etcd.io/etcd/server/v3/storage/backend"
+	"go.etcd.io/etcd/server/v3/storage/mvcc"
+	"go.etcd.io/etcd/server/v3/storage/schema"
+	"go.etcd.io/raft/v3"
+	"go.etcd.io/raft/v3/raftpb"
+)
+
+const (
+	DefaultSnapshotCount = 10000
+
+	// DefaultSnapshotCatchUpEntries is the number of entries for a slow follower
+	// to catch-up after compacting the raft storage entries.
+	// We expect the follower has a millisecond level latency with the leader.
+	// The max throughput is around 10K. Keep a 5K entries is enough for helping
+	// follower to catch up.
+	DefaultSnapshotCatchUpEntries uint64 = 5000
+
+	StoreClusterPrefix = "/0"
+	StoreKeysPrefix    = "/1"
+
+	// HealthInterval is the minimum time the cluster should be healthy
+	// before accepting add and delete member requests.
+	HealthInterval = 5 * time.Second
+
+	purgeFileInterval = 30 * time.Second
+
+	// max number of in-flight snapshot messages etcdserver allows to have
+	// This number is more than enough for most clusters with 5 machines.
+	maxInFlightMsgSnap = 16
+
+	releaseDelayAfterSnapshot = 30 * time.Second
+
+	// maxPendingRevokes is the maximum number of outstanding expired lease revocations.
+	maxPendingRevokes = 16
+
+	recommendedMaxRequestBytes = 10 * 1024 * 1024
+
+	// readyPercentThreshold is a threshold used to determine
+	// whether a learner is ready for a transition into a full voting member or not.
+	readyPercentThreshold = 0.9
+
+	DowngradeEnabledPath = "/downgrade/enabled"
+	memorySnapshotCount  = 100
+)
+
+var (
+	// monitorVersionInterval should be smaller than the timeout
+	// on the connection. Or we will not be able to reuse the connection
+	// (since it will timeout).
+	monitorVersionInterval = rafthttp.ConnWriteTimeout - time.Second
+
+	recommendedMaxRequestBytesString = humanize.Bytes(uint64(recommendedMaxRequestBytes))
+	storeMemberAttributeRegexp       = regexp.MustCompile(path.Join(membership.StoreMembersPrefix, "[[:xdigit:]]{1,16}", "attributes"))
+)
+
+func init() {
+	expvar.Publish(
+		"file_descriptor_limit",
+		expvar.Func(
+			func() any {
+				n, _ := runtime.FDLimit()
+				return n
+			},
+		),
+	)
+}
+
+type Response struct {
+	Term    uint64
+	Index   uint64
+	Event   *v2store.Event
+	Watcher v2store.Watcher
+	Err     error
+}
+
+type ServerV2 interface {
+	Server
+	Leader() types.ID
+
+	ClientCertAuthEnabled() bool
+}
+
+type ServerV3 interface {
+	Server
+	apply.RaftStatusGetter
+}
+
+func (s *EtcdServer) ClientCertAuthEnabled() bool { return s.Cfg.ClientCertAuthEnabled }
+
+type Server interface {
+	// AddMember attempts to add a member into the cluster. It will return
+	// ErrIDRemoved if member ID is removed from the cluster, or return
+	// ErrIDExists if member ID exists in the cluster.
+	AddMember(ctx context.Context, memb membership.Member) ([]*membership.Member, error)
+	// RemoveMember attempts to remove a member from the cluster. It will
+	// return ErrIDRemoved if member ID is removed from the cluster, or return
+	// ErrIDNotFound if member ID is not in the cluster.
+	RemoveMember(ctx context.Context, id uint64) ([]*membership.Member, error)
+	// UpdateMember attempts to update an existing member in the cluster. It will
+	// return ErrIDNotFound if the member ID does not exist.
+	UpdateMember(ctx context.Context, updateMemb membership.Member) ([]*membership.Member, error)
+	// PromoteMember attempts to promote a non-voting node to a voting node. It will
+	// return ErrIDNotFound if the member ID does not exist.
+	// return ErrLearnerNotReady if the member are not ready.
+	// return ErrMemberNotLearner if the member is not a learner.
+	PromoteMember(ctx context.Context, id uint64) ([]*membership.Member, error)
+
+	// ClusterVersion is the cluster-wide minimum major.minor version.
+	// Cluster version is set to the min version that an etcd member is
+	// compatible with when first bootstrap.
+	//
+	// ClusterVersion is nil until the cluster is bootstrapped (has a quorum).
+	//
+	// During a rolling upgrades, the ClusterVersion will be updated
+	// automatically after a sync. (5 second by default)
+	//
+	// The API/raft component can utilize ClusterVersion to determine if
+	// it can accept a client request or a raft RPC.
+	// NOTE: ClusterVersion might be nil when etcd 2.1 works with etcd 2.0 and
+	// the leader is etcd 2.0. etcd 2.0 leader will not update clusterVersion since
+	// this feature is introduced post 2.0.
+	ClusterVersion() *semver.Version
+	// StorageVersion is the storage schema version. It's supported starting
+	// from 3.6.
+	StorageVersion() *semver.Version
+	Cluster() api.Cluster
+	Alarms() []*pb.AlarmMember
+
+	// LeaderChangedNotify returns a channel for application level code to be notified
+	// when etcd leader changes, this function is intend to be used only in application
+	// which embed etcd.
+	// Caution:
+	// 1. the returned channel is being closed when the leadership changes.
+	// 2. so the new channel needs to be obtained for each raft term.
+	// 3. user can loose some consecutive channel changes using this API.
+	LeaderChangedNotify() <-chan struct{}
+}
+
+// EtcdServer is the production implementation of the Server interface
+type EtcdServer struct {
+	// inflightSnapshots holds count the number of snapshots currently inflight.
+	inflightSnapshots int64  // must use atomic operations to access; keep 64-bit aligned.
+	appliedIndex      uint64 // must use atomic operations to access; keep 64-bit aligned.
+	committedIndex    uint64 // must use atomic operations to access; keep 64-bit aligned.
+	term              uint64 // must use atomic operations to access; keep 64-bit aligned.
+	lead              uint64 // must use atomic operations to access; keep 64-bit aligned.
+
+	consistIndex cindex.ConsistentIndexer // consistIndex is used to get/set/save consistentIndex
+	r            raftNode                 // uses 64-bit atomics; keep 64-bit aligned.
+
+	readych chan struct{}
+	Cfg     config.ServerConfig
+
+	lgMu *sync.RWMutex
+	lg   *zap.Logger
+
+	w wait.Wait
+
+	readMu sync.RWMutex
+	// read routine notifies etcd server that it waits for reading by sending an empty struct to
+	// readwaitC
+	readwaitc chan struct{}
+	// readNotifier is used to notify the read routine that it can process the request
+	// when there is no error
+	readNotifier *notifier
+
+	// stop signals the run goroutine should shutdown.
+	stop chan struct{}
+	// stopping is closed by run goroutine on shutdown.
+	stopping chan struct{}
+	// done is closed when all goroutines from start() complete.
+	done chan struct{}
+	// leaderChanged is used to notify the linearizable read loop to drop the old read requests.
+	leaderChanged *notify.Notifier
+
+	errorc     chan error
+	memberID   types.ID
+	attributes membership.Attributes
+
+	cluster *membership.RaftCluster
+
+	v2store     v2store.Store
+	snapshotter *snap.Snapshotter
+
+	uberApply apply.UberApplier
+
+	applyWait wait.WaitTime
+
+	kv         mvcc.WatchableKV
+	lessor     lease.Lessor
+	bemu       sync.RWMutex
+	be         backend.Backend
+	beHooks    *serverstorage.BackendHooks
+	authStore  auth.AuthStore
+	alarmStore *v3alarm.AlarmStore
+
+	stats  *stats.ServerStats
+	lstats *stats.LeaderStats
+
+	SyncTicker *time.Ticker
+	// compactor is used to auto-compact the KV.
+	compactor v3compactor.Compactor
+
+	// peerRt used to send requests (version, lease) to peers.
+	peerRt   http.RoundTripper
+	reqIDGen *idutil.Generator
+
+	// wgMu blocks concurrent waitgroup mutation while server stopping
+	wgMu sync.RWMutex
+	// wg is used to wait for the goroutines that depends on the server state
+	// to exit when stopping the server.
+	wg sync.WaitGroup
+
+	// ctx is used for etcd-initiated requests that may need to be canceled
+	// on etcd server shutdown.
+	ctx    context.Context
+	cancel context.CancelFunc
+
+	leadTimeMu      sync.RWMutex
+	leadElectedTime time.Time
+
+	firstCommitInTerm     *notify.Notifier
+	clusterVersionChanged *notify.Notifier
+
+	*AccessController
+	// forceDiskSnapshot can force snapshot be triggered after apply, independent of the snapshotCount.
+	// Should only be set within apply code path. Used to force snapshot after cluster version downgrade.
+	// TODO: Replace with flush db in v3.7 assuming v3.6 bootstraps from db file.
+	forceDiskSnapshot bool
+	corruptionChecker CorruptionChecker
+}
+
+// NewServer creates a new EtcdServer from the supplied configuration. The
+// configuration is considered static for the lifetime of the EtcdServer.
+func NewServer(cfg config.ServerConfig) (srv *EtcdServer, err error) {
+	b, err := bootstrap(cfg)
+	if err != nil {
+		cfg.Logger.Error("bootstrap failed", zap.Error(err))
+		return nil, err
+	}
+	cfg.Logger.Info("bootstrap successfully")
+
+	defer func() {
+		if err != nil {
+			b.Close()
+		}
+	}()
+
+	sstats := stats.NewServerStats(cfg.Name, b.cluster.cl.String())
+	lstats := stats.NewLeaderStats(cfg.Logger, b.cluster.nodeID.String())
+
+	heartbeat := time.Duration(cfg.TickMs) * time.Millisecond
+	srv = &EtcdServer{
+		readych:               make(chan struct{}),
+		Cfg:                   cfg,
+		lgMu:                  new(sync.RWMutex),
+		lg:                    cfg.Logger,
+		errorc:                make(chan error, 1),
+		v2store:               b.storage.st,
+		snapshotter:           b.ss,
+		r:                     *b.raft.newRaftNode(b.ss, b.storage.wal.w, b.cluster.cl),
+		memberID:              b.cluster.nodeID,
+		attributes:            membership.Attributes{Name: cfg.Name, ClientURLs: cfg.ClientURLs.StringSlice()},
+		cluster:               b.cluster.cl,
+		stats:                 sstats,
+		lstats:                lstats,
+		SyncTicker:            time.NewTicker(500 * time.Millisecond),
+		peerRt:                b.prt,
+		reqIDGen:              idutil.NewGenerator(uint16(b.cluster.nodeID), time.Now()),
+		AccessController:      &AccessController{CORS: cfg.CORS, HostWhitelist: cfg.HostWhitelist},
+		consistIndex:          b.storage.backend.ci,
+		firstCommitInTerm:     notify.NewNotifier(),
+		clusterVersionChanged: notify.NewNotifier(),
+	}
+
+	addFeatureGateMetrics(cfg.ServerFeatureGate, serverFeatureEnabled)
+	serverID.With(prometheus.Labels{"server_id": b.cluster.nodeID.String()}).Set(1)
+	srv.cluster.SetVersionChangedNotifier(srv.clusterVersionChanged)
+
+	srv.be = b.storage.backend.be
+	srv.beHooks = b.storage.backend.beHooks
+	minTTL := time.Duration((3*cfg.ElectionTicks)/2) * heartbeat
+
+	// always recover lessor before kv. When we recover the mvcc.KV it will reattach keys to its leases.
+	// If we recover mvcc.KV first, it will attach the keys to the wrong lessor before it recovers.
+	srv.lessor = lease.NewLessor(srv.Logger(), srv.be, srv.cluster, lease.LessorConfig{
+		MinLeaseTTL:                int64(math.Ceil(minTTL.Seconds())),
+		CheckpointInterval:         cfg.LeaseCheckpointInterval,
+		CheckpointPersist:          cfg.ServerFeatureGate.Enabled(features.LeaseCheckpointPersist),
+		ExpiredLeasesRetryInterval: srv.Cfg.ReqTimeout(),
+	})
+
+	tp, err := auth.NewTokenProvider(cfg.Logger, cfg.AuthToken,
+		func(index uint64) <-chan struct{} {
+			return srv.applyWait.Wait(index)
+		},
+		time.Duration(cfg.TokenTTL)*time.Second,
+	)
+	if err != nil {
+		cfg.Logger.Warn("failed to create token provider", zap.Error(err))
+		return nil, err
+	}
+
+	mvccStoreConfig := mvcc.StoreConfig{
+		CompactionBatchLimit:    cfg.CompactionBatchLimit,
+		CompactionSleepInterval: cfg.CompactionSleepInterval,
+	}
+	srv.kv = mvcc.New(srv.Logger(), srv.be, srv.lessor, mvccStoreConfig)
+	srv.corruptionChecker = newCorruptionChecker(cfg.Logger, srv, srv.kv.HashStorage())
+
+	srv.authStore = auth.NewAuthStore(srv.Logger(), schema.NewAuthBackend(srv.Logger(), srv.be), tp, int(cfg.BcryptCost))
+
+	newSrv := srv // since srv == nil in defer if srv is returned as nil
+	defer func() {
+		// closing backend without first closing kv can cause
+		// resumed compactions to fail with closed tx errors
+		if err != nil {
+			newSrv.kv.Close()
+		}
+	}()
+	if num := cfg.AutoCompactionRetention; num != 0 {
+		srv.compactor, err = v3compactor.New(cfg.Logger, cfg.AutoCompactionMode, num, srv.kv, srv)
+		if err != nil {
+			return nil, err
+		}
+		srv.compactor.Run()
+	}
+
+	if err = srv.restoreAlarms(); err != nil {
+		return nil, err
+	}
+	srv.uberApply = srv.NewUberApplier()
+
+	if srv.FeatureEnabled(features.LeaseCheckpoint) {
+		// setting checkpointer enables lease checkpoint feature.
+		srv.lessor.SetCheckpointer(func(ctx context.Context, cp *pb.LeaseCheckpointRequest) error {
+			if !srv.ensureLeadership() {
+				srv.lg.Warn("Ignore the checkpoint request because current member isn't a leader",
+					zap.Uint64("local-member-id", uint64(srv.MemberID())))
+				return lease.ErrNotPrimary
+			}
+
+			srv.raftRequestOnce(ctx, pb.InternalRaftRequest{LeaseCheckpoint: cp})
+			return nil
+		})
+	}
+
+	// Set the hook after EtcdServer finishes the initialization to avoid
+	// the hook being called during the initialization process.
+	srv.be.SetTxPostLockInsideApplyHook(srv.getTxPostLockInsideApplyHook())
+
+	// TODO: move transport initialization near the definition of remote
+	tr := &rafthttp.Transport{
+		Logger:      cfg.Logger,
+		TLSInfo:     cfg.PeerTLSInfo,
+		DialTimeout: cfg.PeerDialTimeout(),
+		ID:          b.cluster.nodeID,
+		URLs:        cfg.PeerURLs,
+		ClusterID:   b.cluster.cl.ID(),
+		Raft:        srv,
+		Snapshotter: b.ss,
+		ServerStats: sstats,
+		LeaderStats: lstats,
+		ErrorC:      srv.errorc,
+	}
+	if err = tr.Start(); err != nil {
+		return nil, err
+	}
+	// add all remotes into transport
+	for _, m := range b.cluster.remotes {
+		if m.ID != b.cluster.nodeID {
+			tr.AddRemote(m.ID, m.PeerURLs)
+		}
+	}
+	for _, m := range b.cluster.cl.Members() {
+		if m.ID != b.cluster.nodeID {
+			tr.AddPeer(m.ID, m.PeerURLs)
+		}
+	}
+	srv.r.transport = tr
+
+	return srv, nil
+}
+
+func (s *EtcdServer) Logger() *zap.Logger {
+	s.lgMu.RLock()
+	l := s.lg
+	s.lgMu.RUnlock()
+	return l
+}
+
+func (s *EtcdServer) Config() config.ServerConfig {
+	return s.Cfg
+}
+
+// FeatureEnabled returns true if the feature is enabled by the etcd server, false otherwise.
+func (s *EtcdServer) FeatureEnabled(f featuregate.Feature) bool {
+	return s.Cfg.ServerFeatureGate.Enabled(f)
+}
+
+func tickToDur(ticks int, tickMs uint) string {
+	return fmt.Sprintf("%v", time.Duration(ticks)*time.Duration(tickMs)*time.Millisecond)
+}
+
+func (s *EtcdServer) adjustTicks() {
+	lg := s.Logger()
+	clusterN := len(s.cluster.Members())
+
+	// single-node fresh start, or single-node recovers from snapshot
+	if clusterN == 1 {
+		ticks := s.Cfg.ElectionTicks - 1
+		lg.Info(
+			"started as single-node; fast-forwarding election ticks",
+			zap.String("local-member-id", s.MemberID().String()),
+			zap.Int("forward-ticks", ticks),
+			zap.String("forward-duration", tickToDur(ticks, s.Cfg.TickMs)),
+			zap.Int("election-ticks", s.Cfg.ElectionTicks),
+			zap.String("election-timeout", tickToDur(s.Cfg.ElectionTicks, s.Cfg.TickMs)),
+		)
+		s.r.advanceTicks(ticks)
+		return
+	}
+
+	if !s.Cfg.InitialElectionTickAdvance {
+		lg.Info("skipping initial election tick advance", zap.Int("election-ticks", s.Cfg.ElectionTicks))
+		return
+	}
+	lg.Info("starting initial election tick advance", zap.Int("election-ticks", s.Cfg.ElectionTicks))
+
+	// retry up to "rafthttp.ConnReadTimeout", which is 5-sec
+	// until peer connection reports; otherwise:
+	// 1. all connections failed, or
+	// 2. no active peers, or
+	// 3. restarted single-node with no snapshot
+	// then, do nothing, because advancing ticks would have no effect
+	waitTime := rafthttp.ConnReadTimeout
+	itv := 50 * time.Millisecond
+	for i := int64(0); i < int64(waitTime/itv); i++ {
+		select {
+		case <-time.After(itv):
+		case <-s.stopping:
+			return
+		}
+
+		peerN := s.r.transport.ActivePeers()
+		if peerN > 1 {
+			// multi-node received peer connection reports
+			// adjust ticks, in case slow leader message receive
+			ticks := s.Cfg.ElectionTicks - 2
+
+			lg.Info(
+				"initialized peer connections; fast-forwarding election ticks",
+				zap.String("local-member-id", s.MemberID().String()),
+				zap.Int("forward-ticks", ticks),
+				zap.String("forward-duration", tickToDur(ticks, s.Cfg.TickMs)),
+				zap.Int("election-ticks", s.Cfg.ElectionTicks),
+				zap.String("election-timeout", tickToDur(s.Cfg.ElectionTicks, s.Cfg.TickMs)),
+				zap.Int("active-remote-members", peerN),
+			)
+
+			s.r.advanceTicks(ticks)
+			return
+		}
+	}
+}
+
+// Start performs any initialization of the Server necessary for it to
+// begin serving requests. It must be called before Do or Process.
+// Start must be non-blocking; any long-running server functionality
+// should be implemented in goroutines.
+func (s *EtcdServer) Start() {
+	s.start()
+	s.GoAttach(func() { s.adjustTicks() })
+	s.GoAttach(func() { s.publishV3(s.Cfg.ReqTimeout()) })
+	s.GoAttach(s.purgeFile)
+	s.GoAttach(func() { monitorFileDescriptor(s.Logger(), s.stopping) })
+	s.GoAttach(s.monitorClusterVersions)
+	s.GoAttach(s.monitorStorageVersion)
+	s.GoAttach(s.linearizableReadLoop)
+	s.GoAttach(s.monitorKVHash)
+	s.GoAttach(s.monitorCompactHash)
+	s.GoAttach(s.monitorDowngrade)
+}
+
+// start prepares and starts server in a new goroutine. It is no longer safe to
+// modify a server's fields after it has been sent to Start.
+// This function is just used for testing.
+func (s *EtcdServer) start() {
+	lg := s.Logger()
+
+	if s.Cfg.SnapshotCount == 0 {
+		lg.Info(
+			"updating snapshot-count to default",
+			zap.Uint64("given-snapshot-count", s.Cfg.SnapshotCount),
+			zap.Uint64("updated-snapshot-count", DefaultSnapshotCount),
+		)
+		s.Cfg.SnapshotCount = DefaultSnapshotCount
+	}
+	if s.Cfg.SnapshotCatchUpEntries == 0 {
+		lg.Info(
+			"updating snapshot catch-up entries to default",
+			zap.Uint64("given-snapshot-catchup-entries", s.Cfg.SnapshotCatchUpEntries),
+			zap.Uint64("updated-snapshot-catchup-entries", DefaultSnapshotCatchUpEntries),
+		)
+		s.Cfg.SnapshotCatchUpEntries = DefaultSnapshotCatchUpEntries
+	}
+
+	s.w = wait.New()
+	s.applyWait = wait.NewTimeList()
+	s.done = make(chan struct{})
+	s.stop = make(chan struct{})
+	s.stopping = make(chan struct{}, 1)
+	s.ctx, s.cancel = context.WithCancel(context.Background())
+	s.readwaitc = make(chan struct{}, 1)
+	s.readNotifier = newNotifier()
+	s.leaderChanged = notify.NewNotifier()
+	if s.ClusterVersion() != nil {
+		lg.Info(
+			"starting etcd server",
+			zap.String("local-member-id", s.MemberID().String()),
+			zap.String("local-server-version", version.Version),
+			zap.String("cluster-id", s.Cluster().ID().String()),
+			zap.String("cluster-version", version.Cluster(s.ClusterVersion().String())),
+		)
+		membership.ClusterVersionMetrics.With(prometheus.Labels{"cluster_version": version.Cluster(s.ClusterVersion().String())}).Set(1)
+	} else {
+		lg.Info(
+			"starting etcd server",
+			zap.String("local-member-id", s.MemberID().String()),
+			zap.String("local-server-version", version.Version),
+			zap.String("cluster-version", "to_be_decided"),
+		)
+	}
+
+	// TODO: if this is an empty log, writes all peer infos
+	// into the first entry
+	go s.run()
+}
+
+func (s *EtcdServer) purgeFile() {
+	lg := s.Logger()
+	var dberrc, serrc, werrc <-chan error
+	var dbdonec, sdonec, wdonec <-chan struct{}
+	if s.Cfg.MaxSnapFiles > 0 {
+		dbdonec, dberrc = fileutil.PurgeFileWithoutFlock(lg, s.Cfg.SnapDir(), "snap.db", s.Cfg.MaxSnapFiles, purgeFileInterval, s.stopping)
+		sdonec, serrc = fileutil.PurgeFileWithoutFlock(lg, s.Cfg.SnapDir(), "snap", s.Cfg.MaxSnapFiles, purgeFileInterval, s.stopping)
+	}
+	if s.Cfg.MaxWALFiles > 0 {
+		wdonec, werrc = fileutil.PurgeFileWithDoneNotify(lg, s.Cfg.WALDir(), "wal", s.Cfg.MaxWALFiles, purgeFileInterval, s.stopping)
+	}
+
+	select {
+	case e := <-dberrc:
+		lg.Fatal("failed to purge snap db file", zap.Error(e))
+	case e := <-serrc:
+		lg.Fatal("failed to purge snap file", zap.Error(e))
+	case e := <-werrc:
+		lg.Fatal("failed to purge wal file", zap.Error(e))
+	case <-s.stopping:
+		if dbdonec != nil {
+			<-dbdonec
+		}
+		if sdonec != nil {
+			<-sdonec
+		}
+		if wdonec != nil {
+			<-wdonec
+		}
+		return
+	}
+}
+
+func (s *EtcdServer) Cluster() api.Cluster { return s.cluster }
+
+func (s *EtcdServer) ApplyWait() <-chan struct{} { return s.applyWait.Wait(s.getCommittedIndex()) }
+
+type ServerPeer interface {
+	ServerV2
+	RaftHandler() http.Handler
+	LeaseHandler() http.Handler
+}
+
+func (s *EtcdServer) LeaseHandler() http.Handler {
+	if s.lessor == nil {
+		return nil
+	}
+	return leasehttp.NewHandler(s.lessor, s.ApplyWait)
+}
+
+func (s *EtcdServer) RaftHandler() http.Handler { return s.r.transport.Handler() }
+
+type ServerPeerV2 interface {
+	ServerPeer
+	HashKVHandler() http.Handler
+	DowngradeEnabledHandler() http.Handler
+}
+
+func (s *EtcdServer) DowngradeInfo() *serverversion.DowngradeInfo { return s.cluster.DowngradeInfo() }
+
+type downgradeEnabledHandler struct {
+	lg      *zap.Logger
+	cluster api.Cluster
+	server  *EtcdServer
+}
+
+func (s *EtcdServer) DowngradeEnabledHandler() http.Handler {
+	return &downgradeEnabledHandler{
+		lg:      s.Logger(),
+		cluster: s.cluster,
+		server:  s,
+	}
+}
+
+func (h *downgradeEnabledHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodGet {
+		w.Header().Set("Allow", http.MethodGet)
+		http.Error(w, "Method Not Allowed", http.StatusMethodNotAllowed)
+		return
+	}
+
+	w.Header().Set("X-Etcd-Cluster-ID", h.cluster.ID().String())
+
+	if r.URL.Path != DowngradeEnabledPath {
+		http.Error(w, "bad path", http.StatusBadRequest)
+		return
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), h.server.Cfg.ReqTimeout())
+	defer cancel()
+
+	// serve with linearized downgrade info
+	if err := h.server.linearizableReadNotify(ctx); err != nil {
+		http.Error(w, fmt.Sprintf("failed linearized read: %v", err),
+			http.StatusInternalServerError)
+		return
+	}
+	enabled := h.server.DowngradeInfo().Enabled
+	w.Header().Set("Content-Type", "text/plain")
+	w.Write([]byte(strconv.FormatBool(enabled)))
+}
+
+// Process takes a raft message and applies it to the server's raft state
+// machine, respecting any timeout of the given context.
+func (s *EtcdServer) Process(ctx context.Context, m raftpb.Message) error {
+	lg := s.Logger()
+	if s.cluster.IsIDRemoved(types.ID(m.From)) {
+		lg.Warn(
+			"rejected Raft message from removed member",
+			zap.String("local-member-id", s.MemberID().String()),
+			zap.String("removed-member-id", types.ID(m.From).String()),
+		)
+		return httptypes.NewHTTPError(http.StatusForbidden, "cannot process message from removed member")
+	}
+	if s.MemberID() != types.ID(m.To) {
+		lg.Warn(
+			"rejected Raft message to mismatch member",
+			zap.String("local-member-id", s.MemberID().String()),
+			zap.String("mismatch-member-id", types.ID(m.To).String()),
+		)
+		return httptypes.NewHTTPError(http.StatusForbidden, "cannot process message to mismatch member")
+	}
+	if m.Type == raftpb.MsgApp {
+		s.stats.RecvAppendReq(types.ID(m.From).String(), m.Size())
+	}
+	return s.r.Step(ctx, m)
+}
+
+func (s *EtcdServer) IsIDRemoved(id uint64) bool { return s.cluster.IsIDRemoved(types.ID(id)) }
+
+func (s *EtcdServer) ReportUnreachable(id uint64) { s.r.ReportUnreachable(id) }
+
+// ReportSnapshot reports snapshot sent status to the raft state machine,
+// and clears the used snapshot from the snapshot store.
+func (s *EtcdServer) ReportSnapshot(id uint64, status raft.SnapshotStatus) {
+	s.r.ReportSnapshot(id, status)
+}
+
+type etcdProgress struct {
+	confState           raftpb.ConfState
+	diskSnapshotIndex   uint64
+	memorySnapshotIndex uint64
+	appliedt            uint64
+	appliedi            uint64
+}
+
+// raftReadyHandler contains a set of EtcdServer operations to be called by raftNode,
+// and helps decouple state machine logic from Raft algorithms.
+// TODO: add a state machine interface to toApply the commit entries and do snapshot/recover
+type raftReadyHandler struct {
+	getLead              func() (lead uint64)
+	updateLead           func(lead uint64)
+	updateLeadership     func(newLeader bool)
+	updateCommittedIndex func(uint64)
+}
+
+func (s *EtcdServer) run() {
+	lg := s.Logger()
+
+	sn, err := s.r.raftStorage.Snapshot()
+	if err != nil {
+		lg.Panic("failed to get snapshot from Raft storage", zap.Error(err))
+	}
+
+	// asynchronously accept toApply packets, dispatch progress in-order
+	sched := schedule.NewFIFOScheduler(lg)
+
+	rh := &raftReadyHandler{
+		getLead:    func() (lead uint64) { return s.getLead() },
+		updateLead: func(lead uint64) { s.setLead(lead) },
+		updateLeadership: func(newLeader bool) {
+			if !s.isLeader() {
+				if s.lessor != nil {
+					s.lessor.Demote()
+				}
+				if s.compactor != nil {
+					s.compactor.Pause()
+				}
+			} else {
+				if newLeader {
+					t := time.Now()
+					s.leadTimeMu.Lock()
+					s.leadElectedTime = t
+					s.leadTimeMu.Unlock()
+				}
+				if s.compactor != nil {
+					s.compactor.Resume()
+				}
+			}
+			if newLeader {
+				s.leaderChanged.Notify()
+			}
+			// TODO: remove the nil checking
+			// current test utility does not provide the stats
+			if s.stats != nil {
+				s.stats.BecomeLeader()
+			}
+		},
+		updateCommittedIndex: func(ci uint64) {
+			cci := s.getCommittedIndex()
+			if ci > cci {
+				s.setCommittedIndex(ci)
+			}
+		},
+	}
+	s.r.start(rh)
+
+	ep := etcdProgress{
+		confState:           sn.Metadata.ConfState,
+		diskSnapshotIndex:   sn.Metadata.Index,
+		memorySnapshotIndex: sn.Metadata.Index,
+		appliedt:            sn.Metadata.Term,
+		appliedi:            sn.Metadata.Index,
+	}
+
+	defer func() {
+		s.wgMu.Lock() // block concurrent waitgroup adds in GoAttach while stopping
+		close(s.stopping)
+		s.wgMu.Unlock()
+		s.cancel()
+		sched.Stop()
+
+		// wait for goroutines before closing raft so wal stays open
+		s.wg.Wait()
+
+		s.SyncTicker.Stop()
+
+		// must stop raft after scheduler-- etcdserver can leak rafthttp pipelines
+		// by adding a peer after raft stops the transport
+		s.r.stop()
+
+		s.Cleanup()
+
+		close(s.done)
+	}()
+
+	var expiredLeaseC <-chan []*lease.Lease
+	if s.lessor != nil {
+		expiredLeaseC = s.lessor.ExpiredLeasesC()
+	}
+
+	for {
+		select {
+		case ap := <-s.r.apply():
+			f := schedule.NewJob("server_applyAll", func(context.Context) { s.applyAll(&ep, &ap) })
+			sched.Schedule(f)
+		case leases := <-expiredLeaseC:
+			s.revokeExpiredLeases(leases)
+		case err := <-s.errorc:
+			lg.Warn("server error", zap.Error(err))
+			lg.Warn("data-dir used by this member must be removed")
+			return
+		case <-s.stop:
+			return
+		}
+	}
+}
+
+func (s *EtcdServer) revokeExpiredLeases(leases []*lease.Lease) {
+	s.GoAttach(func() {
+		// We shouldn't revoke any leases if current member isn't a leader,
+		// because the operation should only be performed by the leader. When
+		// the leader gets blocked on the raft loop, such as writing WAL entries,
+		// it can't process any events or messages from raft. It may think it
+		// is still the leader even the leader has already changed.
+		// Refer to https://github.com/etcd-io/etcd/issues/15247
+		lg := s.Logger()
+		if !s.ensureLeadership() {
+			lg.Warn("Ignore the lease revoking request because current member isn't a leader",
+				zap.Uint64("local-member-id", uint64(s.MemberID())))
+			return
+		}
+
+		// Increases throughput of expired leases deletion process through parallelization
+		c := make(chan struct{}, maxPendingRevokes)
+		for _, curLease := range leases {
+			select {
+			case c <- struct{}{}:
+			case <-s.stopping:
+				return
+			}
+
+			f := func(lid int64) {
+				s.GoAttach(func() {
+					ctx := s.authStore.WithRoot(s.ctx)
+					_, lerr := s.LeaseRevoke(ctx, &pb.LeaseRevokeRequest{ID: lid})
+					if lerr == nil {
+						leaseExpired.Inc()
+					} else {
+						lg.Warn(
+							"failed to revoke lease",
+							zap.String("lease-id", fmt.Sprintf("%016x", lid)),
+							zap.Error(lerr),
+						)
+					}
+
+					<-c
+				})
+			}
+
+			f(int64(curLease.ID))
+		}
+	})
+}
+
+// isActive checks if the etcd instance is still actively processing the
+// heartbeat message (ticks). It returns false if no heartbeat has been
+// received within 3 * tickMs.
+func (s *EtcdServer) isActive() bool {
+	latestTickTs := s.r.getLatestTickTs()
+	threshold := 3 * time.Duration(s.Cfg.TickMs) * time.Millisecond
+	return latestTickTs.Add(threshold).After(time.Now())
+}
+
+// ensureLeadership checks whether current member is still the leader.
+func (s *EtcdServer) ensureLeadership() bool {
+	lg := s.Logger()
+
+	if s.isActive() {
+		lg.Debug("The member is active, skip checking leadership",
+			zap.Time("latestTickTs", s.r.getLatestTickTs()),
+			zap.Time("now", time.Now()))
+		return true
+	}
+
+	ctx, cancel := context.WithTimeout(s.ctx, s.Cfg.ReqTimeout())
+	defer cancel()
+	if err := s.linearizableReadNotify(ctx); err != nil {
+		lg.Warn("Failed to check current member's leadership",
+			zap.Error(err))
+		return false
+	}
+
+	newLeaderID := s.raftStatus().Lead
+	if newLeaderID != uint64(s.MemberID()) {
+		lg.Warn("Current member isn't a leader",
+			zap.Uint64("local-member-id", uint64(s.MemberID())),
+			zap.Uint64("new-lead", newLeaderID))
+		return false
+	}
+
+	return true
+}
+
+// Cleanup removes allocated objects by EtcdServer.NewServer in
+// situation that EtcdServer::Start was not called (that takes care of cleanup).
+func (s *EtcdServer) Cleanup() {
+	// kv, lessor and backend can be nil if running without v3 enabled
+	// or running unit tests.
+	if s.lessor != nil {
+		s.lessor.Stop()
+	}
+	if s.kv != nil {
+		s.kv.Close()
+	}
+	if s.authStore != nil {
+		s.authStore.Close()
+	}
+	if s.be != nil {
+		s.be.Close()
+	}
+	if s.compactor != nil {
+		s.compactor.Stop()
+	}
+}
+
+func (s *EtcdServer) Defragment() error {
+	s.bemu.Lock()
+	defer s.bemu.Unlock()
+	return s.be.Defrag()
+}
+
+func (s *EtcdServer) applyAll(ep *etcdProgress, apply *toApply) {
+	s.applySnapshot(ep, apply)
+	s.applyEntries(ep, apply)
+	backend.VerifyBackendConsistency(s.Backend(), s.Logger(), true, schema.AllBuckets...)
+
+	proposalsApplied.Set(float64(ep.appliedi))
+	s.applyWait.Trigger(ep.appliedi)
+
+	// wait for the raft routine to finish the disk writes before triggering a
+	// snapshot. or applied index might be greater than the last index in raft
+	// storage, since the raft routine might be slower than toApply routine.
+	<-apply.notifyc
+
+	s.snapshotIfNeededAndCompactRaftLog(ep)
+	select {
+	// snapshot requested via send()
+	case m := <-s.r.msgSnapC:
+		merged := s.createMergedSnapshotMessage(m, ep.appliedt, ep.appliedi, ep.confState)
+		s.sendMergedSnap(merged)
+	default:
+	}
+}
+
+func (s *EtcdServer) applySnapshot(ep *etcdProgress, toApply *toApply) {
+	if raft.IsEmptySnap(toApply.snapshot) {
+		return
+	}
+	applySnapshotInProgress.Inc()
+
+	lg := s.Logger()
+	lg.Info(
+		"applying snapshot",
+		zap.Uint64("current-snapshot-index", ep.diskSnapshotIndex),
+		zap.Uint64("current-applied-index", ep.appliedi),
+		zap.Uint64("incoming-leader-snapshot-index", toApply.snapshot.Metadata.Index),
+		zap.Uint64("incoming-leader-snapshot-term", toApply.snapshot.Metadata.Term),
+	)
+	defer func() {
+		lg.Info(
+			"applied snapshot",
+			zap.Uint64("current-snapshot-index", ep.diskSnapshotIndex),
+			zap.Uint64("current-applied-index", ep.appliedi),
+			zap.Uint64("incoming-leader-snapshot-index", toApply.snapshot.Metadata.Index),
+			zap.Uint64("incoming-leader-snapshot-term", toApply.snapshot.Metadata.Term),
+		)
+		applySnapshotInProgress.Dec()
+	}()
+
+	if toApply.snapshot.Metadata.Index <= ep.appliedi {
+		lg.Panic(
+			"unexpected leader snapshot from outdated index",
+			zap.Uint64("current-snapshot-index", ep.diskSnapshotIndex),
+			zap.Uint64("current-applied-index", ep.appliedi),
+			zap.Uint64("incoming-leader-snapshot-index", toApply.snapshot.Metadata.Index),
+			zap.Uint64("incoming-leader-snapshot-term", toApply.snapshot.Metadata.Term),
+		)
+	}
+
+	// wait for raftNode to persist snapshot onto the disk
+	<-toApply.notifyc
+
+	bemuUnlocked := false
+	s.bemu.Lock()
+	defer func() {
+		if !bemuUnlocked {
+			s.bemu.Unlock()
+		}
+	}()
+
+	// gofail: var applyBeforeOpenSnapshot struct{}
+	newbe, err := serverstorage.OpenSnapshotBackend(s.Cfg, s.snapshotter, toApply.snapshot, s.beHooks)
+	if err != nil {
+		lg.Panic("failed to open snapshot backend", zap.Error(err))
+	}
+	lg.Info("applySnapshot: opened snapshot backend")
+	// gofail: var applyAfterOpenSnapshot struct{}
+
+	// We need to set the backend to consistIndex before recovering the lessor,
+	// because lessor.Recover will commit the boltDB transaction, accordingly it
+	// will get the old consistent_index persisted into the db in OnPreCommitUnsafe.
+	// Eventually the new consistent_index value coming from snapshot is overwritten
+	// by the old value.
+	s.consistIndex.SetBackend(newbe)
+	verifySnapshotIndex(toApply.snapshot, s.consistIndex.ConsistentIndex())
+
+	// always recover lessor before kv. When we recover the mvcc.KV it will reattach keys to its leases.
+	// If we recover mvcc.KV first, it will attach the keys to the wrong lessor before it recovers.
+	if s.lessor != nil {
+		lg.Info("restoring lease store")
+
+		s.lessor.Recover(newbe, func() lease.TxnDelete { return s.kv.Write(traceutil.TODO()) })
+
+		lg.Info("restored lease store")
+	}
+
+	lg.Info("restoring mvcc store")
+
+	if err := s.kv.Restore(newbe); err != nil {
+		lg.Panic("failed to restore mvcc store", zap.Error(err))
+	}
+
+	newbe.SetTxPostLockInsideApplyHook(s.getTxPostLockInsideApplyHook())
+
+	lg.Info("restored mvcc store", zap.Uint64("consistent-index", s.consistIndex.ConsistentIndex()))
+
+	oldbe := s.be
+	s.be = newbe
+	s.bemu.Unlock()
+	bemuUnlocked = true
+
+	// Closing old backend might block until all the txns
+	// on the backend are finished.
+	// We do not want to wait on closing the old backend.
+	go func() {
+		lg.Info("closing old backend file")
+		defer func() {
+			lg.Info("closed old backend file")
+		}()
+		if err := oldbe.Close(); err != nil {
+			lg.Panic("failed to close old backend", zap.Error(err))
+		}
+	}()
+
+	lg.Info("restoring alarm store")
+
+	if err := s.restoreAlarms(); err != nil {
+		lg.Panic("failed to restore alarm store", zap.Error(err))
+	}
+
+	lg.Info("restored alarm store")
+
+	if s.authStore != nil {
+		lg.Info("restoring auth store")
+
+		s.authStore.Recover(schema.NewAuthBackend(lg, newbe))
+
+		lg.Info("restored auth store")
+	}
+
+	lg.Info("restoring v2 store")
+	if err := s.v2store.Recovery(toApply.snapshot.Data); err != nil {
+		lg.Panic("failed to restore v2 store", zap.Error(err))
+	}
+
+	if err := serverstorage.AssertNoV2StoreContent(lg, s.v2store, s.Cfg.V2Deprecation); err != nil {
+		lg.Panic("illegal v2store content", zap.Error(err))
+	}
+
+	lg.Info("restored v2 store")
+
+	s.cluster.SetBackend(schema.NewMembershipBackend(lg, newbe))
+
+	lg.Info("restoring cluster configuration")
+
+	s.cluster.Recover(api.UpdateCapability)
+
+	lg.Info("restored cluster configuration")
+	lg.Info("removing old peers from network")
+
+	// recover raft transport
+	s.r.transport.RemoveAllPeers()
+
+	lg.Info("removed old peers from network")
+	lg.Info("adding peers from new cluster configuration")
+
+	for _, m := range s.cluster.Members() {
+		if m.ID == s.MemberID() {
+			continue
+		}
+		s.r.transport.AddPeer(m.ID, m.PeerURLs)
+	}
+
+	lg.Info("added peers from new cluster configuration")
+
+	ep.appliedt = toApply.snapshot.Metadata.Term
+	ep.appliedi = toApply.snapshot.Metadata.Index
+	ep.diskSnapshotIndex = ep.appliedi
+	ep.memorySnapshotIndex = ep.appliedi
+	ep.confState = toApply.snapshot.Metadata.ConfState
+
+	// As backends and implementations like alarmsStore changed, we need
+	// to re-bootstrap Appliers.
+	s.uberApply = s.NewUberApplier()
+}
+
+func (s *EtcdServer) NewUberApplier() apply.UberApplier {
+	return apply.NewUberApplier(s.lg, s.be, s.KV(), s.alarmStore, s.authStore, s.lessor, s.cluster, s, s, s.consistIndex,
+		s.Cfg.WarningApplyDuration, s.Cfg.ServerFeatureGate.Enabled(features.TxnModeWriteWithSharedBuffer), s.Cfg.QuotaBackendBytes)
+}
+
+func verifySnapshotIndex(snapshot raftpb.Snapshot, cindex uint64) {
+	verify.Verify(func() {
+		if cindex != snapshot.Metadata.Index {
+			panic(fmt.Sprintf("consistent_index(%d) isn't equal to snapshot index (%d)", cindex, snapshot.Metadata.Index))
+		}
+	})
+}
+
+func verifyConsistentIndexIsLatest(lg *zap.Logger, snapshot raftpb.Snapshot, cindex uint64) {
+	verify.Verify(func() {
+		if cindex < snapshot.Metadata.Index {
+			lg.Panic(fmt.Sprintf("consistent_index(%d) is older than snapshot index (%d)", cindex, snapshot.Metadata.Index))
+		}
+	})
+}
+
+func (s *EtcdServer) applyEntries(ep *etcdProgress, apply *toApply) {
+	if len(apply.entries) == 0 {
+		return
+	}
+	firsti := apply.entries[0].Index
+	if firsti > ep.appliedi+1 {
+		lg := s.Logger()
+		lg.Panic(
+			"unexpected committed entry index",
+			zap.Uint64("current-applied-index", ep.appliedi),
+			zap.Uint64("first-committed-entry-index", firsti),
+		)
+	}
+	var ents []raftpb.Entry
+	if ep.appliedi+1-firsti < uint64(len(apply.entries)) {
+		ents = apply.entries[ep.appliedi+1-firsti:]
+	}
+	if len(ents) == 0 {
+		return
+	}
+	var shouldstop bool
+	if ep.appliedt, ep.appliedi, shouldstop = s.apply(ents, &ep.confState, apply.raftAdvancedC); shouldstop {
+		go s.stopWithDelay(10*100*time.Millisecond, fmt.Errorf("the member has been permanently removed from the cluster"))
+	}
+}
+
+func (s *EtcdServer) ForceSnapshot() {
+	s.forceDiskSnapshot = true
+}
+
+func (s *EtcdServer) snapshotIfNeededAndCompactRaftLog(ep *etcdProgress) {
+	// TODO: Remove disk snapshot in v3.7
+	shouldSnapshotToDisk := s.shouldSnapshotToDisk(ep)
+	shouldSnapshotToMemory := s.shouldSnapshotToMemory(ep)
+	if !shouldSnapshotToDisk && !shouldSnapshotToMemory {
+		return
+	}
+	s.snapshot(ep, shouldSnapshotToDisk)
+	s.compactRaftLog(ep.appliedi)
+}
+
+func (s *EtcdServer) shouldSnapshotToDisk(ep *etcdProgress) bool {
+	return (s.forceDiskSnapshot && ep.appliedi != ep.diskSnapshotIndex) || (ep.appliedi-ep.diskSnapshotIndex > s.Cfg.SnapshotCount)
+}
+
+func (s *EtcdServer) shouldSnapshotToMemory(ep *etcdProgress) bool {
+	return ep.appliedi > ep.memorySnapshotIndex+memorySnapshotCount
+}
+
+func (s *EtcdServer) hasMultipleVotingMembers() bool {
+	return s.cluster != nil && len(s.cluster.VotingMemberIDs()) > 1
+}
+
+func (s *EtcdServer) isLeader() bool {
+	return uint64(s.MemberID()) == s.Lead()
+}
+
+// MoveLeader transfers the leader to the given transferee.
+func (s *EtcdServer) MoveLeader(ctx context.Context, lead, transferee uint64) error {
+	member := s.cluster.Member(types.ID(transferee))
+	if member == nil || member.IsLearner {
+		return errors.ErrBadLeaderTransferee
+	}
+
+	now := time.Now()
+	interval := time.Duration(s.Cfg.TickMs) * time.Millisecond
+
+	lg := s.Logger()
+	lg.Info(
+		"leadership transfer starting",
+		zap.String("local-member-id", s.MemberID().String()),
+		zap.String("current-leader-member-id", types.ID(lead).String()),
+		zap.String("transferee-member-id", types.ID(transferee).String()),
+	)
+
+	s.r.TransferLeadership(ctx, lead, transferee)
+	for s.Lead() != transferee {
+		select {
+		case <-ctx.Done(): // time out
+			return errors.ErrTimeoutLeaderTransfer
+		case <-time.After(interval):
+		}
+	}
+
+	// TODO: drain all requests, or drop all messages to the old leader
+	lg.Info(
+		"leadership transfer finished",
+		zap.String("local-member-id", s.MemberID().String()),
+		zap.String("old-leader-member-id", types.ID(lead).String()),
+		zap.String("new-leader-member-id", types.ID(transferee).String()),
+		zap.Duration("took", time.Since(now)),
+	)
+	return nil
+}
+
+// TryTransferLeadershipOnShutdown transfers the leader to the chosen transferee. It is only used in server graceful shutdown.
+func (s *EtcdServer) TryTransferLeadershipOnShutdown() error {
+	lg := s.Logger()
+	if !s.isLeader() {
+		lg.Info(
+			"skipped leadership transfer; local server is not leader",
+			zap.String("local-member-id", s.MemberID().String()),
+			zap.String("current-leader-member-id", types.ID(s.Lead()).String()),
+		)
+		return nil
+	}
+
+	if !s.hasMultipleVotingMembers() {
+		lg.Info(
+			"skipped leadership transfer for single voting member cluster",
+			zap.String("local-member-id", s.MemberID().String()),
+			zap.String("current-leader-member-id", types.ID(s.Lead()).String()),
+		)
+		return nil
+	}
+
+	transferee, ok := longestConnected(s.r.transport, s.cluster.VotingMemberIDs())
+	if !ok {
+		return errors.ErrUnhealthy
+	}
+
+	tm := s.Cfg.ReqTimeout()
+	ctx, cancel := context.WithTimeout(s.ctx, tm)
+	err := s.MoveLeader(ctx, s.Lead(), uint64(transferee))
+	cancel()
+	return err
+}
+
+// HardStop stops the server without coordination with other members in the cluster.
+func (s *EtcdServer) HardStop() {
+	select {
+	case s.stop <- struct{}{}:
+	case <-s.done:
+		return
+	}
+	<-s.done
+}
+
+// Stop stops the server gracefully, and shuts down the running goroutine.
+// Stop should be called after a Start(s), otherwise it will block forever.
+// When stopping leader, Stop transfers its leadership to one of its peers
+// before stopping the server.
+// Stop terminates the Server and performs any necessary finalization.
+// Do and Process cannot be called after Stop has been invoked.
+func (s *EtcdServer) Stop() {
+	lg := s.Logger()
+	if err := s.TryTransferLeadershipOnShutdown(); err != nil {
+		lg.Warn("leadership transfer failed", zap.String("local-member-id", s.MemberID().String()), zap.Error(err))
+	}
+	s.HardStop()
+}
+
+// ReadyNotify returns a channel that will be closed when the server
+// is ready to serve client requests
+func (s *EtcdServer) ReadyNotify() <-chan struct{} { return s.readych }
+
+func (s *EtcdServer) stopWithDelay(d time.Duration, err error) {
+	select {
+	case <-time.After(d):
+	case <-s.done:
+	}
+	select {
+	case s.errorc <- err:
+	default:
+	}
+}
+
+// StopNotify returns a channel that receives an empty struct
+// when the server is stopped.
+func (s *EtcdServer) StopNotify() <-chan struct{} { return s.done }
+
+// StoppingNotify returns a channel that receives an empty struct
+// when the server is being stopped.
+func (s *EtcdServer) StoppingNotify() <-chan struct{} { return s.stopping }
+
+func (s *EtcdServer) checkMembershipOperationPermission(ctx context.Context) error {
+	if s.authStore == nil {
+		// In the context of ordinary etcd process, s.authStore will never be nil.
+		// This branch is for handling cases in server_test.go
+		return nil
+	}
+
+	// Note that this permission check is done in the API layer,
+	// so TOCTOU problem can be caused potentially in a schedule like this:
+	// update membership with user A -> revoke root role of A -> toApply membership change
+	// in the state machine layer
+	// However, both of membership change and role management requires the root privilege.
+	// So careful operation by admins can prevent the problem.
+	authInfo, err := s.AuthInfoFromCtx(ctx)
+	if err != nil {
+		return err
+	}
+
+	return s.AuthStore().IsAdminPermitted(authInfo)
+}
+
+func (s *EtcdServer) AddMember(ctx context.Context, memb membership.Member) ([]*membership.Member, error) {
+	if err := s.checkMembershipOperationPermission(ctx); err != nil {
+		return nil, err
+	}
+
+	// TODO: move Member to protobuf type
+	b, err := json.Marshal(memb)
+	if err != nil {
+		return nil, err
+	}
+
+	// by default StrictReconfigCheck is enabled; reject new members if unhealthy.
+	if err := s.mayAddMember(memb); err != nil {
+		return nil, err
+	}
+
+	cc := raftpb.ConfChange{
+		Type:    raftpb.ConfChangeAddNode,
+		NodeID:  uint64(memb.ID),
+		Context: b,
+	}
+
+	if memb.IsLearner {
+		cc.Type = raftpb.ConfChangeAddLearnerNode
+	}
+
+	return s.configure(ctx, cc)
+}
+
+func (s *EtcdServer) mayAddMember(memb membership.Member) error {
+	lg := s.Logger()
+	if !s.Cfg.StrictReconfigCheck {
+		return nil
+	}
+
+	// protect quorum when adding voting member
+	if !memb.IsLearner && !s.cluster.IsReadyToAddVotingMember() {
+		lg.Warn(
+			"rejecting member add request; not enough healthy members",
+			zap.String("local-member-id", s.MemberID().String()),
+			zap.String("requested-member-add", fmt.Sprintf("%+v", memb)),
+			zap.Error(errors.ErrNotEnoughStartedMembers),
+		)
+		return errors.ErrNotEnoughStartedMembers
+	}
+
+	if !isConnectedFullySince(s.r.transport, time.Now().Add(-HealthInterval), s.MemberID(), s.cluster.VotingMembers()) {
+		lg.Warn(
+			"rejecting member add request; local member has not been connected to all peers, reconfigure breaks active quorum",
+			zap.String("local-member-id", s.MemberID().String()),
+			zap.String("requested-member-add", fmt.Sprintf("%+v", memb)),
+			zap.Error(errors.ErrUnhealthy),
+		)
+		return errors.ErrUnhealthy
+	}
+
+	return nil
+}
+
+func (s *EtcdServer) RemoveMember(ctx context.Context, id uint64) ([]*membership.Member, error) {
+	if err := s.checkMembershipOperationPermission(ctx); err != nil {
+		return nil, err
+	}
+
+	// by default StrictReconfigCheck is enabled; reject removal if leads to quorum loss
+	if err := s.mayRemoveMember(types.ID(id)); err != nil {
+		return nil, err
+	}
+
+	cc := raftpb.ConfChange{
+		Type:   raftpb.ConfChangeRemoveNode,
+		NodeID: id,
+	}
+	return s.configure(ctx, cc)
+}
+
+// PromoteMember promotes a learner node to a voting node.
+func (s *EtcdServer) PromoteMember(ctx context.Context, id uint64) ([]*membership.Member, error) {
+	// only raft leader has information on whether the to-be-promoted learner node is ready. If promoteMember call
+	// fails with ErrNotLeader, forward the request to leader node via HTTP. If promoteMember call fails with error
+	// other than ErrNotLeader, return the error.
+	resp, err := s.promoteMember(ctx, id)
+	if err == nil {
+		learnerPromoteSucceed.Inc()
+		return resp, nil
+	}
+	if !errorspkg.Is(err, errors.ErrNotLeader) {
+		learnerPromoteFailed.WithLabelValues(err.Error()).Inc()
+		return resp, err
+	}
+
+	cctx, cancel := context.WithTimeout(ctx, s.Cfg.ReqTimeout())
+	defer cancel()
+	// forward to leader
+	for cctx.Err() == nil {
+		leader, err := s.waitLeader(cctx)
+		if err != nil {
+			return nil, err
+		}
+		for _, url := range leader.PeerURLs {
+			resp, err := promoteMemberHTTP(cctx, url, id, s.peerRt)
+			if err == nil {
+				return resp, nil
+			}
+			// If member promotion failed, return early. Otherwise keep retry.
+			if errorspkg.Is(err, errors.ErrLearnerNotReady) || errorspkg.Is(err, membership.ErrIDNotFound) || errorspkg.Is(err, membership.ErrMemberNotLearner) {
+				return nil, err
+			}
+		}
+	}
+
+	if errorspkg.Is(cctx.Err(), context.DeadlineExceeded) {
+		return nil, errors.ErrTimeout
+	}
+	return nil, errors.ErrCanceled
+}
+
+// promoteMember checks whether the to-be-promoted learner node is ready before sending the promote
+// request to raft.
+// The function returns ErrNotLeader if the local node is not raft leader (therefore does not have
+// enough information to determine if the learner node is ready), returns ErrLearnerNotReady if the
+// local node is leader (therefore has enough information) but decided the learner node is not ready
+// to be promoted.
+func (s *EtcdServer) promoteMember(ctx context.Context, id uint64) ([]*membership.Member, error) {
+	if err := s.checkMembershipOperationPermission(ctx); err != nil {
+		return nil, err
+	}
+
+	// check if we can promote this learner.
+	if err := s.mayPromoteMember(types.ID(id)); err != nil {
+		return nil, err
+	}
+
+	// build the context for the promote confChange. mark IsLearner to false and IsPromote to true.
+	promoteChangeContext := membership.ConfigChangeContext{
+		Member: membership.Member{
+			ID: types.ID(id),
+		},
+		IsPromote: true,
+	}
+
+	b, err := json.Marshal(promoteChangeContext)
+	if err != nil {
+		return nil, err
+	}
+
+	cc := raftpb.ConfChange{
+		Type:    raftpb.ConfChangeAddNode,
+		NodeID:  id,
+		Context: b,
+	}
+
+	return s.configure(ctx, cc)
+}
+
+func (s *EtcdServer) mayPromoteMember(id types.ID) error {
+	lg := s.Logger()
+	if err := s.isLearnerReady(lg, uint64(id)); err != nil {
+		return err
+	}
+
+	if !s.Cfg.StrictReconfigCheck {
+		return nil
+	}
+	if !s.cluster.IsReadyToPromoteMember(uint64(id)) {
+		lg.Warn(
+			"rejecting member promote request; not enough healthy members",
+			zap.String("local-member-id", s.MemberID().String()),
+			zap.String("requested-member-remove-id", id.String()),
+			zap.Error(errors.ErrNotEnoughStartedMembers),
+		)
+		return errors.ErrNotEnoughStartedMembers
+	}
+
+	return nil
+}
+
+// check whether the learner catches up with leader or not.
+// Note: it will return nil if member is not found in cluster or if member is not learner.
+// These two conditions will be checked before toApply phase later.
+func (s *EtcdServer) isLearnerReady(lg *zap.Logger, id uint64) error {
+	if err := s.waitAppliedIndex(); err != nil {
+		return err
+	}
+
+	rs := s.raftStatus()
+
+	// leader's raftStatus.Progress is not nil
+	if rs.Progress == nil {
+		return errors.ErrNotLeader
+	}
+
+	var learnerMatch uint64
+	isFound := false
+	leaderID := rs.ID
+	for memberID, progress := range rs.Progress {
+		if id == memberID {
+			// check its status
+			learnerMatch = progress.Match
+			isFound = true
+			break
+		}
+	}
+
+	// We should return an error in API directly, to avoid the request
+	// being unnecessarily delivered to raft.
+	if !isFound {
+		return membership.ErrIDNotFound
+	}
+
+	leaderMatch := rs.Progress[leaderID].Match
+
+	learnerReadyPercent := float64(learnerMatch) / float64(leaderMatch)
+
+	// the learner's Match not caught up with leader yet
+	if learnerReadyPercent < readyPercentThreshold {
+		lg.Error(
+			"rejecting promote learner: learner is not ready",
+			zap.Float64("learner-ready-percent", learnerReadyPercent),
+			zap.Float64("ready-percent-threshold", readyPercentThreshold),
+		)
+		return errors.ErrLearnerNotReady
+	}
+
+	return nil
+}
+
+func (s *EtcdServer) mayRemoveMember(id types.ID) error {
+	if !s.Cfg.StrictReconfigCheck {
+		return nil
+	}
+
+	lg := s.Logger()
+	member := s.cluster.Member(id)
+	// no need to check quorum when removing non-voting member
+	if member != nil && member.IsLearner {
+		return nil
+	}
+
+	if !s.cluster.IsReadyToRemoveVotingMember(uint64(id)) {
+		lg.Warn(
+			"rejecting member remove request; not enough healthy members",
+			zap.String("local-member-id", s.MemberID().String()),
+			zap.String("requested-member-remove-id", id.String()),
+			zap.Error(errors.ErrNotEnoughStartedMembers),
+		)
+		return errors.ErrNotEnoughStartedMembers
+	}
+
+	// downed member is safe to remove since it's not part of the active quorum
+	if t := s.r.transport.ActiveSince(id); id != s.MemberID() && t.IsZero() {
+		return nil
+	}
+
+	// protect quorum if some members are down
+	m := s.cluster.VotingMembers()
+	active := numConnectedSince(s.r.transport, time.Now().Add(-HealthInterval), s.MemberID(), m)
+	if (active - 1) < 1+((len(m)-1)/2) {
+		lg.Warn(
+			"rejecting member remove request; local member has not been connected to all peers, reconfigure breaks active quorum",
+			zap.String("local-member-id", s.MemberID().String()),
+			zap.String("requested-member-remove", id.String()),
+			zap.Int("active-peers", active),
+			zap.Error(errors.ErrUnhealthy),
+		)
+		return errors.ErrUnhealthy
+	}
+
+	return nil
+}
+
+func (s *EtcdServer) UpdateMember(ctx context.Context, memb membership.Member) ([]*membership.Member, error) {
+	b, merr := json.Marshal(memb)
+	if merr != nil {
+		return nil, merr
+	}
+
+	if err := s.checkMembershipOperationPermission(ctx); err != nil {
+		return nil, err
+	}
+	cc := raftpb.ConfChange{
+		Type:    raftpb.ConfChangeUpdateNode,
+		NodeID:  uint64(memb.ID),
+		Context: b,
+	}
+	return s.configure(ctx, cc)
+}
+
+func (s *EtcdServer) setCommittedIndex(v uint64) {
+	atomic.StoreUint64(&s.committedIndex, v)
+}
+
+func (s *EtcdServer) getCommittedIndex() uint64 {
+	return atomic.LoadUint64(&s.committedIndex)
+}
+
+func (s *EtcdServer) setAppliedIndex(v uint64) {
+	atomic.StoreUint64(&s.appliedIndex, v)
+}
+
+func (s *EtcdServer) getAppliedIndex() uint64 {
+	return atomic.LoadUint64(&s.appliedIndex)
+}
+
+func (s *EtcdServer) setTerm(v uint64) {
+	atomic.StoreUint64(&s.term, v)
+}
+
+func (s *EtcdServer) getTerm() uint64 {
+	return atomic.LoadUint64(&s.term)
+}
+
+func (s *EtcdServer) setLead(v uint64) {
+	atomic.StoreUint64(&s.lead, v)
+}
+
+func (s *EtcdServer) getLead() uint64 {
+	return atomic.LoadUint64(&s.lead)
+}
+
+func (s *EtcdServer) LeaderChangedNotify() <-chan struct{} {
+	return s.leaderChanged.Receive()
+}
+
+// FirstCommitInTermNotify returns channel that will be unlocked on first
+// entry committed in new term, which is necessary for new leader to answer
+// read-only requests (leader is not able to respond any read-only requests
+// as long as linearizable semantic is required)
+func (s *EtcdServer) FirstCommitInTermNotify() <-chan struct{} {
+	return s.firstCommitInTerm.Receive()
+}
+
+// MemberId returns the ID of the local member.
+// Deprecated: Please use (*EtcdServer) MemberID instead.
+//
+//revive:disable:var-naming
+func (s *EtcdServer) MemberId() types.ID { return s.MemberID() }
+
+//revive:enable:var-naming
+
+func (s *EtcdServer) MemberID() types.ID { return s.memberID }
+
+func (s *EtcdServer) Leader() types.ID { return types.ID(s.getLead()) }
+
+func (s *EtcdServer) Lead() uint64 { return s.getLead() }
+
+func (s *EtcdServer) CommittedIndex() uint64 { return s.getCommittedIndex() }
+
+func (s *EtcdServer) AppliedIndex() uint64 { return s.getAppliedIndex() }
+
+func (s *EtcdServer) Term() uint64 { return s.getTerm() }
+
+type confChangeResponse struct {
+	membs        []*membership.Member
+	raftAdvanceC <-chan struct{}
+	err          error
+}
+
+// configure sends a configuration change through consensus and
+// then waits for it to be applied to the server. It
+// will block until the change is performed or there is an error.
+func (s *EtcdServer) configure(ctx context.Context, cc raftpb.ConfChange) ([]*membership.Member, error) {
+	lg := s.Logger()
+	cc.ID = s.reqIDGen.Next()
+	ch := s.w.Register(cc.ID)
+
+	start := time.Now()
+	if err := s.r.ProposeConfChange(ctx, cc); err != nil {
+		s.w.Trigger(cc.ID, nil)
+		return nil, err
+	}
+
+	select {
+	case x := <-ch:
+		if x == nil {
+			lg.Panic("failed to configure")
+		}
+		resp := x.(*confChangeResponse)
+		// etcdserver need to ensure the raft has already been notified
+		// or advanced before it responds to the client. Otherwise, the
+		// following config change request may be rejected.
+		// See https://github.com/etcd-io/etcd/issues/15528.
+		<-resp.raftAdvanceC
+		lg.Info(
+			"applied a configuration change through raft",
+			zap.String("local-member-id", s.MemberID().String()),
+			zap.String("raft-conf-change", cc.Type.String()),
+			zap.String("raft-conf-change-node-id", types.ID(cc.NodeID).String()),
+		)
+		return resp.membs, resp.err
+
+	case <-ctx.Done():
+		s.w.Trigger(cc.ID, nil) // GC wait
+		return nil, s.parseProposeCtxErr(ctx.Err(), start)
+
+	case <-s.stopping:
+		return nil, errors.ErrStopped
+	}
+}
+
+// publishV3 registers server information into the cluster using v3 request. The
+// information is the JSON representation of this server's member struct, updated
+// with the static clientURLs of the server.
+// The function keeps attempting to register until it succeeds,
+// or its server is stopped.
+func (s *EtcdServer) publishV3(timeout time.Duration) {
+	req := &membershippb.ClusterMemberAttrSetRequest{
+		Member_ID: uint64(s.MemberID()),
+		MemberAttributes: &membershippb.Attributes{
+			Name:       s.attributes.Name,
+			ClientUrls: s.attributes.ClientURLs,
+		},
+	}
+	// gofail: var beforePublishing struct{}
+	lg := s.Logger()
+	for {
+		select {
+		case <-s.stopping:
+			lg.Warn(
+				"stopped publish because server is stopping",
+				zap.String("local-member-id", s.MemberID().String()),
+				zap.String("local-member-attributes", fmt.Sprintf("%+v", s.attributes)),
+				zap.Duration("publish-timeout", timeout),
+			)
+			return
+
+		default:
+		}
+
+		ctx, cancel := context.WithTimeout(s.ctx, timeout)
+		_, err := s.raftRequest(ctx, pb.InternalRaftRequest{ClusterMemberAttrSet: req})
+		cancel()
+		switch err {
+		case nil:
+			close(s.readych)
+			lg.Info(
+				"published local member to cluster through raft",
+				zap.String("local-member-id", s.MemberID().String()),
+				zap.String("local-member-attributes", fmt.Sprintf("%+v", s.attributes)),
+				zap.String("cluster-id", s.cluster.ID().String()),
+				zap.Duration("publish-timeout", timeout),
+			)
+			return
+
+		default:
+			lg.Warn(
+				"failed to publish local member to cluster through raft",
+				zap.String("local-member-id", s.MemberID().String()),
+				zap.String("local-member-attributes", fmt.Sprintf("%+v", s.attributes)),
+				zap.Duration("publish-timeout", timeout),
+				zap.Error(err),
+			)
+		}
+	}
+}
+
+func (s *EtcdServer) sendMergedSnap(merged snap.Message) {
+	atomic.AddInt64(&s.inflightSnapshots, 1)
+
+	lg := s.Logger()
+	fields := []zap.Field{
+		zap.String("from", s.MemberID().String()),
+		zap.String("to", types.ID(merged.To).String()),
+		zap.Int64("bytes", merged.TotalSize),
+		zap.String("size", humanize.Bytes(uint64(merged.TotalSize))),
+	}
+
+	now := time.Now()
+	s.r.transport.SendSnapshot(merged)
+	lg.Info("sending merged snapshot", fields...)
+
+	s.GoAttach(func() {
+		select {
+		case ok := <-merged.CloseNotify():
+			// delay releasing inflight snapshot for another 30 seconds to
+			// block log compaction.
+			// If the follower still fails to catch up, it is probably just too slow
+			// to catch up. We cannot avoid the snapshot cycle anyway.
+			if ok {
+				select {
+				case <-time.After(releaseDelayAfterSnapshot):
+				case <-s.stopping:
+				}
+			}
+
+			atomic.AddInt64(&s.inflightSnapshots, -1)
+
+			lg.Info("sent merged snapshot", append(fields, zap.Duration("took", time.Since(now)))...)
+
+		case <-s.stopping:
+			lg.Warn("canceled sending merged snapshot; server stopping", fields...)
+			return
+		}
+	})
+}
+
+// toApply takes entries received from Raft (after it has been committed) and
+// applies them to the current state of the EtcdServer.
+// The given entries should not be empty.
+func (s *EtcdServer) apply(
+	es []raftpb.Entry,
+	confState *raftpb.ConfState,
+	raftAdvancedC <-chan struct{},
+) (appliedt uint64, appliedi uint64, shouldStop bool) {
+	s.lg.Debug("Applying entries", zap.Int("num-entries", len(es)))
+	for i := range es {
+		e := es[i]
+		index := s.consistIndex.ConsistentIndex()
+		s.lg.Debug("Applying entry",
+			zap.Uint64("consistent-index", index),
+			zap.Uint64("entry-index", e.Index),
+			zap.Uint64("entry-term", e.Term),
+			zap.Stringer("entry-type", e.Type))
+
+		// We need to toApply all WAL entries on top of v2store
+		// and only 'unapplied' (e.Index>backend.ConsistentIndex) on the backend.
+		shouldApplyV3 := membership.ApplyV2storeOnly
+		if e.Index > index {
+			shouldApplyV3 = membership.ApplyBoth
+			// set the consistent index of current executing entry
+			s.consistIndex.SetConsistentApplyingIndex(e.Index, e.Term)
+		}
+		switch e.Type {
+		case raftpb.EntryNormal:
+			// gofail: var beforeApplyOneEntryNormal struct{}
+			s.applyEntryNormal(&e, shouldApplyV3)
+			s.setAppliedIndex(e.Index)
+			s.setTerm(e.Term)
+
+		case raftpb.EntryConfChange:
+			// gofail: var beforeApplyOneConfChange struct{}
+			var cc raftpb.ConfChange
+			pbutil.MustUnmarshal(&cc, e.Data)
+			removedSelf, err := s.applyConfChange(cc, confState, shouldApplyV3)
+			s.setAppliedIndex(e.Index)
+			s.setTerm(e.Term)
+			shouldStop = shouldStop || removedSelf
+			s.w.Trigger(cc.ID, &confChangeResponse{s.cluster.Members(), raftAdvancedC, err})
+
+		default:
+			lg := s.Logger()
+			lg.Panic(
+				"unknown entry type; must be either EntryNormal or EntryConfChange",
+				zap.String("type", e.Type.String()),
+			)
+		}
+		appliedi, appliedt = e.Index, e.Term
+	}
+	return appliedt, appliedi, shouldStop
+}
+
+// applyEntryNormal applies an EntryNormal type raftpb request to the EtcdServer
+func (s *EtcdServer) applyEntryNormal(e *raftpb.Entry, shouldApplyV3 membership.ShouldApplyV3) {
+	var ar *apply.Result
+	if shouldApplyV3 {
+		defer func() {
+			// The txPostLockInsideApplyHook will not get called in some cases,
+			// in which we should move the consistent index forward directly.
+			newIndex := s.consistIndex.ConsistentIndex()
+			if newIndex < e.Index {
+				s.consistIndex.SetConsistentIndex(e.Index, e.Term)
+			}
+		}()
+	}
+
+	// raft state machine may generate noop entry when leader confirmation.
+	// skip it in advance to avoid some potential bug in the future
+	if len(e.Data) == 0 {
+		s.firstCommitInTerm.Notify()
+
+		// promote lessor when the local member is leader and finished
+		// applying all entries from the last term.
+		if s.isLeader() {
+			s.lessor.Promote(s.Cfg.ElectionTimeout())
+		}
+		return
+	}
+
+	var raftReq pb.InternalRaftRequest
+	if !pbutil.MaybeUnmarshal(&raftReq, e.Data) { // backward compatible
+		var r pb.Request
+		rp := &r
+		pbutil.MustUnmarshal(rp, e.Data)
+		s.lg.Debug("applyEntryNormal", zap.Stringer("V2request", rp))
+		raftReq = v2ToV3Request(s.lg, (*RequestV2)(rp))
+	}
+	s.lg.Debug("applyEntryNormal", zap.Stringer("raftReq", &raftReq))
+
+	if raftReq.V2 != nil {
+		req := (*RequestV2)(raftReq.V2)
+		raftReq = v2ToV3Request(s.lg, req)
+	}
+
+	id := raftReq.ID
+	if id == 0 {
+		if raftReq.Header == nil {
+			s.lg.Panic("applyEntryNormal, could not find a header")
+		}
+		id = raftReq.Header.ID
+	}
+
+	needResult := s.w.IsRegistered(id)
+	if needResult || !noSideEffect(&raftReq) {
+		if !needResult && raftReq.Txn != nil {
+			removeNeedlessRangeReqs(raftReq.Txn)
+		}
+		ar = s.applyInternalRaftRequest(&raftReq, shouldApplyV3)
+	}
+
+	// do not re-toApply applied entries.
+	if !shouldApplyV3 {
+		return
+	}
+
+	if ar == nil {
+		return
+	}
+
+	if !errorspkg.Is(ar.Err, errors.ErrNoSpace) || len(s.alarmStore.Get(pb.AlarmType_NOSPACE)) > 0 {
+		s.w.Trigger(id, ar)
+		return
+	}
+
+	lg := s.Logger()
+	lg.Warn(
+		"message exceeded backend quota; raising alarm",
+		zap.Int64("quota-size-bytes", s.Cfg.QuotaBackendBytes),
+		zap.String("quota-size", humanize.Bytes(uint64(s.Cfg.QuotaBackendBytes))),
+		zap.Error(ar.Err),
+	)
+
+	s.GoAttach(func() {
+		a := &pb.AlarmRequest{
+			MemberID: uint64(s.MemberID()),
+			Action:   pb.AlarmRequest_ACTIVATE,
+			Alarm:    pb.AlarmType_NOSPACE,
+		}
+		s.raftRequest(s.ctx, pb.InternalRaftRequest{Alarm: a})
+		s.w.Trigger(id, ar)
+	})
+}
+
+func (s *EtcdServer) applyInternalRaftRequest(r *pb.InternalRaftRequest, shouldApplyV3 membership.ShouldApplyV3) *apply.Result {
+	if r.ClusterVersionSet == nil && r.ClusterMemberAttrSet == nil && r.DowngradeInfoSet == nil && r.DowngradeVersionTest == nil {
+		if !shouldApplyV3 {
+			return nil
+		}
+		return s.uberApply.Apply(r)
+	}
+	membershipApplier := apply.NewApplierMembership(s.lg, s.cluster, s)
+	op := "unknown"
+	defer func(start time.Time) {
+		txn.ApplySecObserve("v3", op, true, time.Since(start))
+		txn.WarnOfExpensiveRequest(s.lg, s.Cfg.WarningApplyDuration, start, &pb.InternalRaftStringer{Request: r}, nil, nil)
+	}(time.Now())
+	switch {
+	case r.ClusterVersionSet != nil:
+		op = "ClusterVersionSet" // Implemented in 3.5.x
+		membershipApplier.ClusterVersionSet(r.ClusterVersionSet, shouldApplyV3)
+		return &apply.Result{}
+	case r.ClusterMemberAttrSet != nil:
+		op = "ClusterMemberAttrSet" // Implemented in 3.5.x
+		membershipApplier.ClusterMemberAttrSet(r.ClusterMemberAttrSet, shouldApplyV3)
+	case r.DowngradeInfoSet != nil:
+		op = "DowngradeInfoSet" // Implemented in 3.5.x
+		membershipApplier.DowngradeInfoSet(r.DowngradeInfoSet, shouldApplyV3)
+	case r.DowngradeVersionTest != nil:
+		op = "DowngradeVersionTest" // Implemented in 3.6 for test only
+		// do nothing, we are just to ensure etcdserver don't panic in case
+		// users(test cases) intentionally inject DowngradeVersionTestRequest
+		// into the WAL files.
+	default:
+		s.lg.Panic("not implemented apply", zap.Stringer("raft-request", r))
+		return nil
+	}
+	return &apply.Result{}
+}
+
+func noSideEffect(r *pb.InternalRaftRequest) bool {
+	return r.Range != nil || r.AuthUserGet != nil || r.AuthRoleGet != nil || r.AuthStatus != nil
+}
+
+func removeNeedlessRangeReqs(txn *pb.TxnRequest) {
+	f := func(ops []*pb.RequestOp) []*pb.RequestOp {
+		j := 0
+		for i := 0; i < len(ops); i++ {
+			if _, ok := ops[i].Request.(*pb.RequestOp_RequestRange); ok {
+				continue
+			}
+			ops[j] = ops[i]
+			j++
+		}
+
+		return ops[:j]
+	}
+
+	txn.Success = f(txn.Success)
+	txn.Failure = f(txn.Failure)
+}
+
+// applyConfChange applies a ConfChange to the server. It is only
+// invoked with a ConfChange that has already passed through Raft
+func (s *EtcdServer) applyConfChange(cc raftpb.ConfChange, confState *raftpb.ConfState, shouldApplyV3 membership.ShouldApplyV3) (bool, error) {
+	lg := s.Logger()
+	if err := s.cluster.ValidateConfigurationChange(cc, shouldApplyV3); err != nil {
+		lg.Error("Validation on configuration change failed", zap.Bool("shouldApplyV3", bool(shouldApplyV3)), zap.Error(err))
+		cc.NodeID = raft.None
+		s.r.ApplyConfChange(cc)
+
+		// The txPostLock callback will not get called in this case,
+		// so we should set the consistent index directly.
+		if s.consistIndex != nil && membership.ApplyBoth == shouldApplyV3 {
+			applyingIndex, applyingTerm := s.consistIndex.ConsistentApplyingIndex()
+			s.consistIndex.SetConsistentIndex(applyingIndex, applyingTerm)
+		}
+		return false, err
+	}
+
+	*confState = *s.r.ApplyConfChange(cc)
+	s.beHooks.SetConfState(confState)
+	switch cc.Type {
+	case raftpb.ConfChangeAddNode, raftpb.ConfChangeAddLearnerNode:
+		confChangeContext := new(membership.ConfigChangeContext)
+		if err := json.Unmarshal(cc.Context, confChangeContext); err != nil {
+			lg.Panic("failed to unmarshal member", zap.Error(err))
+		}
+		if cc.NodeID != uint64(confChangeContext.Member.ID) {
+			lg.Panic(
+				"got different member ID",
+				zap.String("member-id-from-config-change-entry", types.ID(cc.NodeID).String()),
+				zap.String("member-id-from-message", confChangeContext.Member.ID.String()),
+			)
+		}
+		if confChangeContext.IsPromote {
+			s.cluster.PromoteMember(confChangeContext.Member.ID, shouldApplyV3)
+		} else {
+			s.cluster.AddMember(&confChangeContext.Member, shouldApplyV3)
+
+			if confChangeContext.Member.ID != s.MemberID() {
+				s.r.transport.AddPeer(confChangeContext.Member.ID, confChangeContext.PeerURLs)
+			}
+		}
+
+	case raftpb.ConfChangeRemoveNode:
+		id := types.ID(cc.NodeID)
+		s.cluster.RemoveMember(id, shouldApplyV3)
+		if id == s.MemberID() {
+			return true, nil
+		}
+		s.r.transport.RemovePeer(id)
+
+	case raftpb.ConfChangeUpdateNode:
+		m := new(membership.Member)
+		if err := json.Unmarshal(cc.Context, m); err != nil {
+			lg.Panic("failed to unmarshal member", zap.Error(err))
+		}
+		if cc.NodeID != uint64(m.ID) {
+			lg.Panic(
+				"got different member ID",
+				zap.String("member-id-from-config-change-entry", types.ID(cc.NodeID).String()),
+				zap.String("member-id-from-message", m.ID.String()),
+			)
+		}
+		s.cluster.UpdateRaftAttributes(m.ID, m.RaftAttributes, shouldApplyV3)
+		if m.ID != s.MemberID() {
+			s.r.transport.UpdatePeer(m.ID, m.PeerURLs)
+		}
+	}
+
+	verify.Verify(func() {
+		s.verifyV3StoreInSyncWithV2Store(shouldApplyV3)
+	})
+
+	return false, nil
+}
+
+func (s *EtcdServer) verifyV3StoreInSyncWithV2Store(shouldApplyV3 membership.ShouldApplyV3) {
+	// If shouldApplyV3 == false, then it means v2store hasn't caught up with v3store.
+	if !shouldApplyV3 {
+		return
+	}
+
+	// clean up the Attributes, and we only care about the RaftAttributes
+	cleanAttributesFunc := func(members map[types.ID]*membership.Member) map[types.ID]*membership.Member {
+		processedMembers := make(map[types.ID]*membership.Member)
+		for id, m := range members {
+			clonedMember := m.Clone()
+			clonedMember.Attributes = membership.Attributes{}
+			processedMembers[id] = clonedMember
+		}
+
+		return processedMembers
+	}
+
+	v2Members, _ := s.cluster.MembersFromStore()
+	v3Members, _ := s.cluster.MembersFromBackend()
+
+	processedV2Members := cleanAttributesFunc(v2Members)
+	processedV3Members := cleanAttributesFunc(v3Members)
+
+	if match := reflect.DeepEqual(processedV2Members, processedV3Members); !match {
+		v2Data, v2Err := json.Marshal(processedV2Members)
+		v3Data, v3Err := json.Marshal(processedV3Members)
+
+		if v2Err != nil || v3Err != nil {
+			panic("members in v2store doesn't match v3store")
+		}
+		panic(fmt.Sprintf("members in v2store doesn't match v3store, v2store: %s, v3store: %s", string(v2Data), string(v3Data)))
+	}
+}
+
+// TODO: non-blocking snapshot
+func (s *EtcdServer) snapshot(ep *etcdProgress, toDisk bool) {
+	lg := s.Logger()
+	d := GetMembershipInfoInV2Format(lg, s.cluster)
+	if toDisk {
+		s.Logger().Info(
+			"triggering snapshot",
+			zap.String("local-member-id", s.MemberID().String()),
+			zap.Uint64("local-member-applied-index", ep.appliedi),
+			zap.Uint64("local-member-snapshot-index", ep.diskSnapshotIndex),
+			zap.Uint64("local-member-snapshot-count", s.Cfg.SnapshotCount),
+			zap.Bool("snapshot-forced", s.forceDiskSnapshot),
+		)
+		s.forceDiskSnapshot = false
+		// commit kv to write metadata (for example: consistent index) to disk.
+		//
+		// This guarantees that Backend's consistent_index is >= index of last snapshot.
+		//
+		// KV().commit() updates the consistent index in backend.
+		// All operations that update consistent index must be called sequentially
+		// from applyAll function.
+		// So KV().Commit() cannot run in parallel with toApply. It has to be called outside
+		// the go routine created below.
+		s.KV().Commit()
+	}
+
+	// For backward compatibility, generate v2 snapshot from v3 state.
+	snap, err := s.r.raftStorage.CreateSnapshot(ep.appliedi, &ep.confState, d)
+	if err != nil {
+		// the snapshot was done asynchronously with the progress of raft.
+		// raft might have already got a newer snapshot.
+		if errorspkg.Is(err, raft.ErrSnapOutOfDate) {
+			return
+		}
+		lg.Panic("failed to create snapshot", zap.Error(err))
+	}
+	ep.memorySnapshotIndex = ep.appliedi
+
+	verifyConsistentIndexIsLatest(lg, snap, s.consistIndex.ConsistentIndex())
+
+	if toDisk {
+		// SaveSnap saves the snapshot to file and appends the corresponding WAL entry.
+		if err = s.r.storage.SaveSnap(snap); err != nil {
+			lg.Panic("failed to save snapshot", zap.Error(err))
+		}
+		ep.diskSnapshotIndex = ep.appliedi
+		if err = s.r.storage.Release(snap); err != nil {
+			lg.Panic("failed to release wal", zap.Error(err))
+		}
+
+		lg.Info(
+			"saved snapshot to disk",
+			zap.Uint64("snapshot-index", snap.Metadata.Index),
+		)
+	}
+}
+
+func (s *EtcdServer) compactRaftLog(snapi uint64) {
+	lg := s.Logger()
+
+	// When sending a snapshot, etcd will pause compaction.
+	// After receives a snapshot, the slow follower needs to get all the entries right after
+	// the snapshot sent to catch up. If we do not pause compaction, the log entries right after
+	// the snapshot sent might already be compacted. It happens when the snapshot takes long time
+	// to send and save. Pausing compaction avoids triggering a snapshot sending cycle.
+	if atomic.LoadInt64(&s.inflightSnapshots) != 0 {
+		lg.Info("skip compaction since there is an inflight snapshot")
+		return
+	}
+
+	// keep some in memory log entries for slow followers.
+	compacti := uint64(1)
+	if snapi > s.Cfg.SnapshotCatchUpEntries {
+		compacti = snapi - s.Cfg.SnapshotCatchUpEntries
+	}
+	err := s.r.raftStorage.Compact(compacti)
+	if err != nil {
+		// the compaction was done asynchronously with the progress of raft.
+		// raft log might already been compact.
+		if errorspkg.Is(err, raft.ErrCompacted) {
+			return
+		}
+		lg.Panic("failed to compact", zap.Error(err))
+	}
+	lg.Debug(
+		"compacted Raft logs",
+		zap.Uint64("compact-index", compacti),
+	)
+}
+
+// CutPeer drops messages to the specified peer.
+func (s *EtcdServer) CutPeer(id types.ID) {
+	tr, ok := s.r.transport.(*rafthttp.Transport)
+	if ok {
+		tr.CutPeer(id)
+	}
+}
+
+// MendPeer recovers the message dropping behavior of the given peer.
+func (s *EtcdServer) MendPeer(id types.ID) {
+	tr, ok := s.r.transport.(*rafthttp.Transport)
+	if ok {
+		tr.MendPeer(id)
+	}
+}
+
+func (s *EtcdServer) PauseSending() { s.r.pauseSending() }
+
+func (s *EtcdServer) ResumeSending() { s.r.resumeSending() }
+
+func (s *EtcdServer) ClusterVersion() *semver.Version {
+	if s.cluster == nil {
+		return nil
+	}
+	return s.cluster.Version()
+}
+
+func (s *EtcdServer) StorageVersion() *semver.Version {
+	// `applySnapshot` sets a new backend instance, so we need to acquire the bemu lock.
+	s.bemu.RLock()
+	defer s.bemu.RUnlock()
+
+	v, err := schema.DetectSchemaVersion(s.lg, s.be.ReadTx())
+	if err != nil {
+		s.lg.Warn("Failed to detect schema version", zap.Error(err))
+		return nil
+	}
+	return &v
+}
+
+// monitorClusterVersions every monitorVersionInterval checks if it's the leader and updates cluster version if needed.
+func (s *EtcdServer) monitorClusterVersions() {
+	lg := s.Logger()
+	monitor := serverversion.NewMonitor(lg, NewServerVersionAdapter(s))
+	for {
+		select {
+		case <-s.firstCommitInTerm.Receive():
+		case <-time.After(monitorVersionInterval):
+		case <-s.stopping:
+			lg.Info("server has stopped; stopping cluster version's monitor")
+			return
+		}
+
+		if s.Leader() != s.MemberID() {
+			continue
+		}
+		err := monitor.UpdateClusterVersionIfNeeded()
+		if err != nil {
+			s.lg.Error("Failed to monitor cluster version", zap.Error(err))
+		}
+	}
+}
+
+// monitorStorageVersion every monitorVersionInterval updates storage version if needed.
+func (s *EtcdServer) monitorStorageVersion() {
+	lg := s.Logger()
+	monitor := serverversion.NewMonitor(lg, NewServerVersionAdapter(s))
+	for {
+		select {
+		case <-time.After(monitorVersionInterval):
+		case <-s.clusterVersionChanged.Receive():
+		case <-s.stopping:
+			lg.Info("server has stopped; stopping storage version's monitor")
+			return
+		}
+		monitor.UpdateStorageVersionIfNeeded()
+	}
+}
+
+func (s *EtcdServer) monitorKVHash() {
+	t := s.Cfg.CorruptCheckTime
+	if t == 0 {
+		return
+	}
+	checkTicker := time.NewTicker(t)
+	defer checkTicker.Stop()
+
+	lg := s.Logger()
+	lg.Info(
+		"enabled corruption checking",
+		zap.String("local-member-id", s.MemberID().String()),
+		zap.Duration("interval", t),
+	)
+	for {
+		select {
+		case <-s.stopping:
+			lg.Info("server has stopped; stopping kv hash's monitor")
+			return
+		case <-checkTicker.C:
+		}
+		backend.VerifyBackendConsistency(s.be, lg, false, schema.AllBuckets...)
+		if !s.isLeader() {
+			continue
+		}
+		if err := s.corruptionChecker.PeriodicCheck(); err != nil {
+			lg.Warn("failed to check hash KV", zap.Error(err))
+		}
+	}
+}
+
+func (s *EtcdServer) monitorCompactHash() {
+	if !s.FeatureEnabled(features.CompactHashCheck) {
+		return
+	}
+	t := s.Cfg.CompactHashCheckTime
+	for {
+		select {
+		case <-time.After(t):
+		case <-s.stopping:
+			lg := s.Logger()
+			lg.Info("server has stopped; stopping compact hash's monitor")
+			return
+		}
+		if !s.isLeader() {
+			continue
+		}
+		s.corruptionChecker.CompactHashCheck()
+	}
+}
+
+func (s *EtcdServer) updateClusterVersionV3(ver string) {
+	lg := s.Logger()
+
+	if s.cluster.Version() == nil {
+		lg.Info(
+			"setting up initial cluster version using v3 API",
+			zap.String("cluster-version", version.Cluster(ver)),
+		)
+	} else {
+		lg.Info(
+			"updating cluster version using v3 API",
+			zap.String("from", version.Cluster(s.cluster.Version().String())),
+			zap.String("to", version.Cluster(ver)),
+		)
+	}
+
+	req := membershippb.ClusterVersionSetRequest{Ver: ver}
+
+	ctx, cancel := context.WithTimeout(s.ctx, s.Cfg.ReqTimeout())
+	_, err := s.raftRequest(ctx, pb.InternalRaftRequest{ClusterVersionSet: &req})
+	cancel()
+
+	switch {
+	case errorspkg.Is(err, nil):
+		lg.Info("cluster version is updated", zap.String("cluster-version", version.Cluster(ver)))
+		return
+
+	case errorspkg.Is(err, errors.ErrStopped):
+		lg.Warn("aborting cluster version update; server is stopped", zap.Error(err))
+		return
+
+	default:
+		lg.Warn("failed to update cluster version", zap.Error(err))
+	}
+}
+
+// monitorDowngrade every DowngradeCheckTime checks if it's the leader and cancels downgrade if needed.
+func (s *EtcdServer) monitorDowngrade() {
+	monitor := serverversion.NewMonitor(s.Logger(), NewServerVersionAdapter(s))
+	t := s.Cfg.DowngradeCheckTime
+	if t == 0 {
+		return
+	}
+	for {
+		select {
+		case <-time.After(t):
+		case <-s.stopping:
+			return
+		}
+
+		if !s.isLeader() {
+			continue
+		}
+		monitor.CancelDowngradeIfNeeded()
+	}
+}
+
+func (s *EtcdServer) parseProposeCtxErr(err error, start time.Time) error {
+	switch {
+	case errorspkg.Is(err, context.Canceled):
+		return errors.ErrCanceled
+
+	case errorspkg.Is(err, context.DeadlineExceeded):
+		s.leadTimeMu.RLock()
+		curLeadElected := s.leadElectedTime
+		s.leadTimeMu.RUnlock()
+		prevLeadLost := curLeadElected.Add(-2 * time.Duration(s.Cfg.ElectionTicks) * time.Duration(s.Cfg.TickMs) * time.Millisecond)
+		if start.After(prevLeadLost) && start.Before(curLeadElected) {
+			return errors.ErrTimeoutDueToLeaderFail
+		}
+		lead := types.ID(s.getLead())
+		switch lead {
+		case types.ID(raft.None):
+			// TODO: return error to specify it happens because the cluster does not have leader now
+		case s.MemberID():
+			if !isConnectedToQuorumSince(s.r.transport, start, s.MemberID(), s.cluster.Members()) {
+				return errors.ErrTimeoutDueToConnectionLost
+			}
+		default:
+			if !isConnectedSince(s.r.transport, start, lead) {
+				return errors.ErrTimeoutDueToConnectionLost
+			}
+		}
+		return errors.ErrTimeout
+
+	default:
+		return err
+	}
+}
+
+func (s *EtcdServer) KV() mvcc.WatchableKV { return s.kv }
+func (s *EtcdServer) Backend() backend.Backend {
+	s.bemu.RLock()
+	defer s.bemu.RUnlock()
+	return s.be
+}
+
+func (s *EtcdServer) AuthStore() auth.AuthStore { return s.authStore }
+
+func (s *EtcdServer) restoreAlarms() error {
+	as, err := v3alarm.NewAlarmStore(s.lg, schema.NewAlarmBackend(s.lg, s.be))
+	if err != nil {
+		return err
+	}
+	s.alarmStore = as
+	return nil
+}
+
+// GoAttach creates a goroutine on a given function and tracks it using
+// the etcdserver waitgroup.
+// The passed function should interrupt on s.StoppingNotify().
+func (s *EtcdServer) GoAttach(f func()) {
+	s.wgMu.RLock() // this blocks with ongoing close(s.stopping)
+	defer s.wgMu.RUnlock()
+	select {
+	case <-s.stopping:
+		lg := s.Logger()
+		lg.Warn("server has stopped; skipping GoAttach")
+		return
+	default:
+	}
+
+	// now safe to add since waitgroup wait has not started yet
+	s.wg.Add(1)
+	go func() {
+		defer s.wg.Done()
+		f()
+	}()
+}
+
+func (s *EtcdServer) Alarms() []*pb.AlarmMember {
+	return s.alarmStore.Get(pb.AlarmType_NONE)
+}
+
+// IsLearner returns if the local member is raft learner
+func (s *EtcdServer) IsLearner() bool {
+	return s.cluster.IsLocalMemberLearner()
+}
+
+// IsMemberExist returns if the member with the given id exists in cluster.
+func (s *EtcdServer) IsMemberExist(id types.ID) bool {
+	return s.cluster.IsMemberExist(id)
+}
+
+// raftStatus returns the raft status of this etcd node.
+func (s *EtcdServer) raftStatus() raft.Status {
+	return s.r.Node.Status()
+}
+
+func (s *EtcdServer) Version() *serverversion.Manager {
+	return serverversion.NewManager(s.Logger(), NewServerVersionAdapter(s))
+}
+
+func (s *EtcdServer) getTxPostLockInsideApplyHook() func() {
+	return func() {
+		applyingIdx, applyingTerm := s.consistIndex.ConsistentApplyingIndex()
+		if applyingIdx > s.consistIndex.UnsafeConsistentIndex() {
+			s.consistIndex.SetConsistentIndex(applyingIdx, applyingTerm)
+		}
+	}
+}
+
+func (s *EtcdServer) CorruptionChecker() CorruptionChecker {
+	return s.corruptionChecker
+}
+
+func addFeatureGateMetrics(fg featuregate.FeatureGate, guageVec *prometheus.GaugeVec) {
+	for feature, featureSpec := range fg.(featuregate.MutableFeatureGate).GetAll() {
+		var metricVal float64
+		if fg.Enabled(feature) {
+			metricVal = 1
+		} else {
+			metricVal = 0
+		}
+		guageVec.With(prometheus.Labels{"name": string(feature), "stage": string(featureSpec.PreRelease)}).Set(metricVal)
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/server_access_control.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/server_access_control.go
new file mode 100644
index 0000000..09e2255
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/server_access_control.go
@@ -0,0 +1,65 @@
+// Copyright 2018 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package etcdserver
+
+import "sync"
+
+// AccessController controls etcd server HTTP request access.
+type AccessController struct {
+	corsMu          sync.RWMutex
+	CORS            map[string]struct{}
+	hostWhitelistMu sync.RWMutex
+	HostWhitelist   map[string]struct{}
+}
+
+// NewAccessController returns a new "AccessController" with default "*" values.
+func NewAccessController() *AccessController {
+	return &AccessController{
+		CORS:          map[string]struct{}{"*": {}},
+		HostWhitelist: map[string]struct{}{"*": {}},
+	}
+}
+
+// OriginAllowed determines whether the server will allow a given CORS origin.
+// If CORS is empty, allow all.
+func (ac *AccessController) OriginAllowed(origin string) bool {
+	ac.corsMu.RLock()
+	defer ac.corsMu.RUnlock()
+	if len(ac.CORS) == 0 { // allow all
+		return true
+	}
+	_, ok := ac.CORS["*"]
+	if ok {
+		return true
+	}
+	_, ok = ac.CORS[origin]
+	return ok
+}
+
+// IsHostWhitelisted returns true if the host is whitelisted.
+// If whitelist is empty, allow all.
+func (ac *AccessController) IsHostWhitelisted(host string) bool {
+	ac.hostWhitelistMu.RLock()
+	defer ac.hostWhitelistMu.RUnlock()
+	if len(ac.HostWhitelist) == 0 { // allow all
+		return true
+	}
+	_, ok := ac.HostWhitelist["*"]
+	if ok {
+		return true
+	}
+	_, ok = ac.HostWhitelist[host]
+	return ok
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/snapshot_merge.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/snapshot_merge.go
new file mode 100644
index 0000000..cc3c545
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/snapshot_merge.go
@@ -0,0 +1,83 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package etcdserver
+
+import (
+	"io"
+
+	humanize "github.com/dustin/go-humanize"
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/server/v3/etcdserver/api/snap"
+	"go.etcd.io/etcd/server/v3/storage/backend"
+	"go.etcd.io/raft/v3/raftpb"
+)
+
+// createMergedSnapshotMessage creates a snapshot message that contains: raft status (term, conf),
+// a snapshot of v2 store inside raft.Snapshot as []byte, a snapshot of v3 KV in the top level message
+// as ReadCloser.
+func (s *EtcdServer) createMergedSnapshotMessage(m raftpb.Message, snapt, snapi uint64, confState raftpb.ConfState) snap.Message {
+	lg := s.Logger()
+	// get a snapshot of v2 store as []byte
+	d := GetMembershipInfoInV2Format(lg, s.cluster)
+
+	// commit kv to write metadata(for example: consistent index).
+	s.KV().Commit()
+	dbsnap := s.be.Snapshot()
+	// get a snapshot of v3 KV as readCloser
+	rc := newSnapshotReaderCloser(lg, dbsnap)
+
+	// put the []byte snapshot of store into raft snapshot and return the merged snapshot with
+	// KV readCloser snapshot.
+	snapshot := raftpb.Snapshot{
+		Metadata: raftpb.SnapshotMetadata{
+			Index:     snapi,
+			Term:      snapt,
+			ConfState: confState,
+		},
+		Data: d,
+	}
+	m.Snapshot = &snapshot
+
+	verifySnapshotIndex(snapshot, s.consistIndex.ConsistentIndex())
+
+	return *snap.NewMessage(m, rc, dbsnap.Size())
+}
+
+func newSnapshotReaderCloser(lg *zap.Logger, snapshot backend.Snapshot) io.ReadCloser {
+	pr, pw := io.Pipe()
+	go func() {
+		n, err := snapshot.WriteTo(pw)
+		if err == nil {
+			lg.Info(
+				"sent database snapshot to writer",
+				zap.Int64("bytes", n),
+				zap.String("size", humanize.Bytes(uint64(n))),
+			)
+		} else {
+			lg.Warn(
+				"failed to send database snapshot to writer",
+				zap.String("size", humanize.Bytes(uint64(n))),
+				zap.Error(err),
+			)
+		}
+		pw.CloseWithError(err)
+		err = snapshot.Close()
+		if err != nil {
+			lg.Panic("failed to close database snapshot", zap.Error(err))
+		}
+	}()
+	return pr
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/txn/metrics.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/txn/metrics.go
new file mode 100644
index 0000000..93f2e07
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/txn/metrics.go
@@ -0,0 +1,71 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package txn
+
+import (
+	"strconv"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+var (
+	slowApplies = prometheus.NewCounter(prometheus.CounterOpts{
+		Namespace: "etcd",
+		Subsystem: "server",
+		Name:      "slow_apply_total",
+		Help:      "The total number of slow apply requests (likely overloaded from slow disk).",
+	})
+	applySec = prometheus.NewHistogramVec(
+		prometheus.HistogramOpts{
+			Namespace: "etcd",
+			Subsystem: "server",
+			Name:      "apply_duration_seconds",
+			Help:      "The latency distributions of v2 apply called by backend.",
+
+			// lowest bucket start of upper bound 0.0001 sec (0.1 ms) with factor 2
+			// highest bucket start of 0.0001 sec * 2^19 == 52.4288 sec
+			Buckets: prometheus.ExponentialBuckets(0.0001, 2, 20),
+		},
+		[]string{"version", "op", "success"},
+	)
+	rangeSec = prometheus.NewHistogramVec(
+		prometheus.HistogramOpts{
+			Namespace: "etcd",
+			Subsystem: "server",
+			Name:      "range_duration_seconds",
+			Help:      "The latency distributions of txn.Range",
+
+			// lowest bucket start of upper bound 0.0001 sec (0.1 ms) with factor 2
+			// highest bucket start of 0.0001 sec * 2^19 == 52.4288 sec
+			Buckets: prometheus.ExponentialBuckets(0.0001, 2, 20),
+		},
+		[]string{"success"},
+	)
+)
+
+func ApplySecObserve(version, op string, success bool, latency time.Duration) {
+	applySec.WithLabelValues(version, op, strconv.FormatBool(success)).Observe(float64(latency.Microseconds()) / 1000000.0)
+}
+
+func RangeSecObserve(success bool, latency time.Duration) {
+	rangeSec.WithLabelValues(strconv.FormatBool(success)).Observe(float64(latency.Microseconds()) / 1000000.0)
+}
+
+func init() {
+	prometheus.MustRegister(applySec)
+	prometheus.MustRegister(rangeSec)
+	prometheus.MustRegister(slowApplies)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/txn/txn.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/txn/txn.go
new file mode 100644
index 0000000..51f70a0
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/txn/txn.go
@@ -0,0 +1,723 @@
+// Copyright 2022 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package txn
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"sort"
+	"time"
+
+	"go.uber.org/zap"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/api/v3/mvccpb"
+	"go.etcd.io/etcd/pkg/v3/traceutil"
+	"go.etcd.io/etcd/server/v3/auth"
+	"go.etcd.io/etcd/server/v3/etcdserver/errors"
+	"go.etcd.io/etcd/server/v3/lease"
+	"go.etcd.io/etcd/server/v3/storage/mvcc"
+)
+
+func Put(ctx context.Context, lg *zap.Logger, lessor lease.Lessor, kv mvcc.KV, p *pb.PutRequest) (resp *pb.PutResponse, trace *traceutil.Trace, err error) {
+	trace = traceutil.Get(ctx)
+	// create put tracing if the trace in context is empty
+	if trace.IsEmpty() {
+		trace = traceutil.New("put",
+			lg,
+			traceutil.Field{Key: "key", Value: string(p.Key)},
+			traceutil.Field{Key: "req_size", Value: p.Size()},
+		)
+		ctx = context.WithValue(ctx, traceutil.TraceKey{}, trace)
+	}
+	leaseID := lease.LeaseID(p.Lease)
+	if leaseID != lease.NoLease {
+		if l := lessor.Lookup(leaseID); l == nil {
+			return nil, nil, lease.ErrLeaseNotFound
+		}
+	}
+	txnWrite := kv.Write(trace)
+	defer txnWrite.End()
+	resp, err = put(ctx, txnWrite, p)
+	return resp, trace, err
+}
+
+func put(ctx context.Context, txnWrite mvcc.TxnWrite, p *pb.PutRequest) (resp *pb.PutResponse, err error) {
+	trace := traceutil.Get(ctx)
+	resp = &pb.PutResponse{}
+	resp.Header = &pb.ResponseHeader{}
+	val, leaseID := p.Value, lease.LeaseID(p.Lease)
+
+	var rr *mvcc.RangeResult
+	if p.IgnoreValue || p.IgnoreLease || p.PrevKv {
+		trace.StepWithFunction(func() {
+			rr, err = txnWrite.Range(context.TODO(), p.Key, nil, mvcc.RangeOptions{})
+		}, "get previous kv pair")
+
+		if err != nil {
+			return nil, err
+		}
+	}
+	if p.IgnoreValue || p.IgnoreLease {
+		if rr == nil || len(rr.KVs) == 0 {
+			// ignore_{lease,value} flag expects previous key-value pair
+			return nil, errors.ErrKeyNotFound
+		}
+	}
+	if p.IgnoreValue {
+		val = rr.KVs[0].Value
+	}
+	if p.IgnoreLease {
+		leaseID = lease.LeaseID(rr.KVs[0].Lease)
+	}
+	if p.PrevKv {
+		if rr != nil && len(rr.KVs) != 0 {
+			resp.PrevKv = &rr.KVs[0]
+		}
+	}
+
+	resp.Header.Revision = txnWrite.Put(p.Key, val, leaseID)
+	trace.AddField(traceutil.Field{Key: "response_revision", Value: resp.Header.Revision})
+	return resp, nil
+}
+
+func DeleteRange(ctx context.Context, lg *zap.Logger, kv mvcc.KV, dr *pb.DeleteRangeRequest) (resp *pb.DeleteRangeResponse, trace *traceutil.Trace, err error) {
+	trace = traceutil.Get(ctx)
+	// create delete tracing if the trace in context is empty
+	if trace.IsEmpty() {
+		trace = traceutil.New("delete_range",
+			lg,
+			traceutil.Field{Key: "key", Value: string(dr.Key)},
+			traceutil.Field{Key: "range_end", Value: string(dr.RangeEnd)},
+		)
+		ctx = context.WithValue(ctx, traceutil.TraceKey{}, trace)
+	}
+	txnWrite := kv.Write(trace)
+	defer txnWrite.End()
+	resp, err = deleteRange(ctx, txnWrite, dr)
+	return resp, trace, err
+}
+
+func deleteRange(ctx context.Context, txnWrite mvcc.TxnWrite, dr *pb.DeleteRangeRequest) (*pb.DeleteRangeResponse, error) {
+	resp := &pb.DeleteRangeResponse{}
+	resp.Header = &pb.ResponseHeader{}
+	end := mkGteRange(dr.RangeEnd)
+
+	if dr.PrevKv {
+		rr, err := txnWrite.Range(ctx, dr.Key, end, mvcc.RangeOptions{})
+		if err != nil {
+			return nil, err
+		}
+		if rr != nil {
+			resp.PrevKvs = make([]*mvccpb.KeyValue, len(rr.KVs))
+			for i := range rr.KVs {
+				resp.PrevKvs[i] = &rr.KVs[i]
+			}
+		}
+	}
+
+	resp.Deleted, resp.Header.Revision = txnWrite.DeleteRange(dr.Key, end)
+	return resp, nil
+}
+
+func Range(ctx context.Context, lg *zap.Logger, kv mvcc.KV, r *pb.RangeRequest) (resp *pb.RangeResponse, trace *traceutil.Trace, err error) {
+	trace = traceutil.Get(ctx)
+	if trace.IsEmpty() {
+		trace = traceutil.New("range", lg)
+		ctx = context.WithValue(ctx, traceutil.TraceKey{}, trace)
+	}
+	defer func(start time.Time) {
+		success := err == nil
+		RangeSecObserve(success, time.Since(start))
+	}(time.Now())
+	txnRead := kv.Read(mvcc.ConcurrentReadTxMode, trace)
+	defer txnRead.End()
+	resp, err = executeRange(ctx, lg, txnRead, r)
+	return resp, trace, err
+}
+
+func executeRange(ctx context.Context, lg *zap.Logger, txnRead mvcc.TxnRead, r *pb.RangeRequest) (*pb.RangeResponse, error) {
+	trace := traceutil.Get(ctx)
+
+	resp := &pb.RangeResponse{}
+	resp.Header = &pb.ResponseHeader{}
+
+	limit := r.Limit
+	if r.SortOrder != pb.RangeRequest_NONE ||
+		r.MinModRevision != 0 || r.MaxModRevision != 0 ||
+		r.MinCreateRevision != 0 || r.MaxCreateRevision != 0 {
+		// fetch everything; sort and truncate afterwards
+		limit = 0
+	}
+	if limit > 0 {
+		// fetch one extra for 'more' flag
+		limit = limit + 1
+	}
+
+	ro := mvcc.RangeOptions{
+		Limit: limit,
+		Rev:   r.Revision,
+		Count: r.CountOnly,
+	}
+
+	rr, err := txnRead.Range(ctx, r.Key, mkGteRange(r.RangeEnd), ro)
+	if err != nil {
+		return nil, err
+	}
+
+	if r.MaxModRevision != 0 {
+		f := func(kv *mvccpb.KeyValue) bool { return kv.ModRevision > r.MaxModRevision }
+		pruneKVs(rr, f)
+	}
+	if r.MinModRevision != 0 {
+		f := func(kv *mvccpb.KeyValue) bool { return kv.ModRevision < r.MinModRevision }
+		pruneKVs(rr, f)
+	}
+	if r.MaxCreateRevision != 0 {
+		f := func(kv *mvccpb.KeyValue) bool { return kv.CreateRevision > r.MaxCreateRevision }
+		pruneKVs(rr, f)
+	}
+	if r.MinCreateRevision != 0 {
+		f := func(kv *mvccpb.KeyValue) bool { return kv.CreateRevision < r.MinCreateRevision }
+		pruneKVs(rr, f)
+	}
+
+	sortOrder := r.SortOrder
+	if r.SortTarget != pb.RangeRequest_KEY && sortOrder == pb.RangeRequest_NONE {
+		// Since current mvcc.Range implementation returns results
+		// sorted by keys in lexiographically ascending order,
+		// sort ASCEND by default only when target is not 'KEY'
+		sortOrder = pb.RangeRequest_ASCEND
+	} else if r.SortTarget == pb.RangeRequest_KEY && sortOrder == pb.RangeRequest_ASCEND {
+		// Since current mvcc.Range implementation returns results
+		// sorted by keys in lexiographically ascending order,
+		// don't re-sort when target is 'KEY' and order is ASCEND
+		sortOrder = pb.RangeRequest_NONE
+	}
+	if sortOrder != pb.RangeRequest_NONE {
+		var sorter sort.Interface
+		switch {
+		case r.SortTarget == pb.RangeRequest_KEY:
+			sorter = &kvSortByKey{&kvSort{rr.KVs}}
+		case r.SortTarget == pb.RangeRequest_VERSION:
+			sorter = &kvSortByVersion{&kvSort{rr.KVs}}
+		case r.SortTarget == pb.RangeRequest_CREATE:
+			sorter = &kvSortByCreate{&kvSort{rr.KVs}}
+		case r.SortTarget == pb.RangeRequest_MOD:
+			sorter = &kvSortByMod{&kvSort{rr.KVs}}
+		case r.SortTarget == pb.RangeRequest_VALUE:
+			sorter = &kvSortByValue{&kvSort{rr.KVs}}
+		default:
+			lg.Panic("unexpected sort target", zap.Int32("sort-target", int32(r.SortTarget)))
+		}
+		switch {
+		case sortOrder == pb.RangeRequest_ASCEND:
+			sort.Sort(sorter)
+		case sortOrder == pb.RangeRequest_DESCEND:
+			sort.Sort(sort.Reverse(sorter))
+		}
+	}
+
+	if r.Limit > 0 && len(rr.KVs) > int(r.Limit) {
+		rr.KVs = rr.KVs[:r.Limit]
+		resp.More = true
+	}
+	trace.Step("filter and sort the key-value pairs")
+	resp.Header.Revision = rr.Rev
+	resp.Count = int64(rr.Count)
+	resp.Kvs = make([]*mvccpb.KeyValue, len(rr.KVs))
+	for i := range rr.KVs {
+		if r.KeysOnly {
+			rr.KVs[i].Value = nil
+		}
+		resp.Kvs[i] = &rr.KVs[i]
+	}
+	trace.Step("assemble the response")
+	return resp, nil
+}
+
+func Txn(ctx context.Context, lg *zap.Logger, rt *pb.TxnRequest, txnModeWriteWithSharedBuffer bool, kv mvcc.KV, lessor lease.Lessor) (*pb.TxnResponse, *traceutil.Trace, error) {
+	trace := traceutil.Get(ctx)
+	if trace.IsEmpty() {
+		trace = traceutil.New("transaction", lg)
+		ctx = context.WithValue(ctx, traceutil.TraceKey{}, trace)
+	}
+	isWrite := !IsTxnReadonly(rt)
+	// When the transaction contains write operations, we use ReadTx instead of
+	// ConcurrentReadTx to avoid extra overhead of copying buffer.
+	var mode mvcc.ReadTxMode
+	if isWrite && txnModeWriteWithSharedBuffer /*a.s.Cfg.ServerFeatureGate.Enabled(features.TxnModeWriteWithSharedBuffer)*/ {
+		mode = mvcc.SharedBufReadTxMode
+	} else {
+		mode = mvcc.ConcurrentReadTxMode
+	}
+	txnRead := kv.Read(mode, trace)
+	var txnPath []bool
+	trace.StepWithFunction(
+		func() {
+			txnPath = compareToPath(txnRead, rt)
+		},
+		"compare",
+	)
+	if isWrite {
+		trace.AddField(traceutil.Field{Key: "read_only", Value: false})
+	}
+	_, err := checkTxn(txnRead, rt, lessor, txnPath)
+	if err != nil {
+		txnRead.End()
+		return nil, nil, err
+	}
+	trace.Step("check requests")
+	// When executing mutable txnWrite ops, etcd must hold the txnWrite lock so
+	// readers do not see any intermediate results. Since writes are
+	// serialized on the raft loop, the revision in the read view will
+	// be the revision of the write txnWrite.
+	var txnWrite mvcc.TxnWrite
+	if isWrite {
+		txnRead.End()
+		txnWrite = kv.Write(trace)
+	} else {
+		txnWrite = mvcc.NewReadOnlyTxnWrite(txnRead)
+	}
+	txnResp, err := txn(ctx, lg, txnWrite, rt, isWrite, txnPath)
+	txnWrite.End()
+
+	trace.AddField(
+		traceutil.Field{Key: "number_of_response", Value: len(txnResp.Responses)},
+		traceutil.Field{Key: "response_revision", Value: txnResp.Header.Revision},
+	)
+	return txnResp, trace, err
+}
+
+func txn(ctx context.Context, lg *zap.Logger, txnWrite mvcc.TxnWrite, rt *pb.TxnRequest, isWrite bool, txnPath []bool) (*pb.TxnResponse, error) {
+	txnResp, _ := newTxnResp(rt, txnPath)
+	_, err := executeTxn(ctx, lg, txnWrite, rt, txnPath, txnResp)
+	if err != nil {
+		if isWrite {
+			// CAUTION: When a txn performing write operations starts, we always expect it to be successful.
+			// If a write failure is seen we SHOULD NOT try to recover the server, but crash with a panic to make the failure explicit.
+			// Trying to silently recover (e.g by ignoring the failed txn or calling txn.End() early) poses serious risks:
+			// - violation of transaction atomicity if some write operations have been partially executed
+			// - data inconsistency across different etcd members if they applied the txn asymmetrically
+			lg.Panic("unexpected error during txn with writes", zap.Error(err))
+		} else {
+			lg.Error("unexpected error during readonly txn", zap.Error(err))
+		}
+	}
+	rev := txnWrite.Rev()
+	if len(txnWrite.Changes()) != 0 {
+		rev++
+	}
+	txnResp.Header.Revision = rev
+	return txnResp, err
+}
+
+// newTxnResp allocates a txn response for a txn request given a path.
+func newTxnResp(rt *pb.TxnRequest, txnPath []bool) (txnResp *pb.TxnResponse, txnCount int) {
+	reqs := rt.Success
+	if !txnPath[0] {
+		reqs = rt.Failure
+	}
+	resps := make([]*pb.ResponseOp, len(reqs))
+	txnResp = &pb.TxnResponse{
+		Responses: resps,
+		Succeeded: txnPath[0],
+		Header:    &pb.ResponseHeader{},
+	}
+	for i, req := range reqs {
+		switch tv := req.Request.(type) {
+		case *pb.RequestOp_RequestRange:
+			resps[i] = &pb.ResponseOp{Response: &pb.ResponseOp_ResponseRange{}}
+		case *pb.RequestOp_RequestPut:
+			resps[i] = &pb.ResponseOp{Response: &pb.ResponseOp_ResponsePut{}}
+		case *pb.RequestOp_RequestDeleteRange:
+			resps[i] = &pb.ResponseOp{Response: &pb.ResponseOp_ResponseDeleteRange{}}
+		case *pb.RequestOp_RequestTxn:
+			resp, txns := newTxnResp(tv.RequestTxn, txnPath[1:])
+			resps[i] = &pb.ResponseOp{Response: &pb.ResponseOp_ResponseTxn{ResponseTxn: resp}}
+			txnPath = txnPath[1+txns:]
+			txnCount += txns + 1
+		default:
+		}
+	}
+	return txnResp, txnCount
+}
+
+func executeTxn(ctx context.Context, lg *zap.Logger, txnWrite mvcc.TxnWrite, rt *pb.TxnRequest, txnPath []bool, tresp *pb.TxnResponse) (txns int, err error) {
+	trace := traceutil.Get(ctx)
+	reqs := rt.Success
+	if !txnPath[0] {
+		reqs = rt.Failure
+	}
+
+	for i, req := range reqs {
+		respi := tresp.Responses[i].Response
+		switch tv := req.Request.(type) {
+		case *pb.RequestOp_RequestRange:
+			trace.StartSubTrace(
+				traceutil.Field{Key: "req_type", Value: "range"},
+				traceutil.Field{Key: "range_begin", Value: string(tv.RequestRange.Key)},
+				traceutil.Field{Key: "range_end", Value: string(tv.RequestRange.RangeEnd)})
+			resp, err := executeRange(ctx, lg, txnWrite, tv.RequestRange)
+			if err != nil {
+				return 0, fmt.Errorf("applyTxn: failed Range: %w", err)
+			}
+			respi.(*pb.ResponseOp_ResponseRange).ResponseRange = resp
+			trace.StopSubTrace()
+		case *pb.RequestOp_RequestPut:
+			trace.StartSubTrace(
+				traceutil.Field{Key: "req_type", Value: "put"},
+				traceutil.Field{Key: "key", Value: string(tv.RequestPut.Key)},
+				traceutil.Field{Key: "req_size", Value: tv.RequestPut.Size()})
+			resp, err := put(ctx, txnWrite, tv.RequestPut)
+			if err != nil {
+				return 0, fmt.Errorf("applyTxn: failed Put: %w", err)
+			}
+			respi.(*pb.ResponseOp_ResponsePut).ResponsePut = resp
+			trace.StopSubTrace()
+		case *pb.RequestOp_RequestDeleteRange:
+			resp, err := deleteRange(ctx, txnWrite, tv.RequestDeleteRange)
+			if err != nil {
+				return 0, fmt.Errorf("applyTxn: failed DeleteRange: %w", err)
+			}
+			respi.(*pb.ResponseOp_ResponseDeleteRange).ResponseDeleteRange = resp
+		case *pb.RequestOp_RequestTxn:
+			resp := respi.(*pb.ResponseOp_ResponseTxn).ResponseTxn
+			applyTxns, err := executeTxn(ctx, lg, txnWrite, tv.RequestTxn, txnPath[1:], resp)
+			if err != nil {
+				// don't wrap the error. It's a recursive call and err should be already wrapped
+				return 0, err
+			}
+			txns += applyTxns + 1
+			txnPath = txnPath[applyTxns+1:]
+		default:
+			// empty union
+		}
+	}
+	return txns, nil
+}
+
+func checkPut(rv mvcc.ReadView, lessor lease.Lessor, req *pb.PutRequest) error {
+	if req.IgnoreValue || req.IgnoreLease {
+		// expects previous key-value, error if not exist
+		rr, err := rv.Range(context.TODO(), req.Key, nil, mvcc.RangeOptions{})
+		if err != nil {
+			return err
+		}
+		if rr == nil || len(rr.KVs) == 0 {
+			return errors.ErrKeyNotFound
+		}
+	}
+	if lease.LeaseID(req.Lease) != lease.NoLease {
+		if l := lessor.Lookup(lease.LeaseID(req.Lease)); l == nil {
+			return lease.ErrLeaseNotFound
+		}
+	}
+	return nil
+}
+
+func checkRange(rv mvcc.ReadView, req *pb.RangeRequest) error {
+	switch {
+	case req.Revision == 0:
+		return nil
+	case req.Revision > rv.Rev():
+		return mvcc.ErrFutureRev
+	case req.Revision < rv.FirstRev():
+		return mvcc.ErrCompacted
+	}
+	return nil
+}
+
+func checkTxn(rv mvcc.ReadView, rt *pb.TxnRequest, lessor lease.Lessor, txnPath []bool) (int, error) {
+	txnCount := 0
+	reqs := rt.Success
+	if !txnPath[0] {
+		reqs = rt.Failure
+	}
+	for _, req := range reqs {
+		var err error
+		var txns int
+		switch tv := req.Request.(type) {
+		case *pb.RequestOp_RequestRange:
+			err = checkRange(rv, tv.RequestRange)
+		case *pb.RequestOp_RequestPut:
+			err = checkPut(rv, lessor, tv.RequestPut)
+		case *pb.RequestOp_RequestDeleteRange:
+		case *pb.RequestOp_RequestTxn:
+			txns, err = checkTxn(rv, tv.RequestTxn, lessor, txnPath[1:])
+			txnCount += txns + 1
+			txnPath = txnPath[txns+1:]
+		default:
+			// empty union
+		}
+		if err != nil {
+			return 0, err
+		}
+	}
+	return txnCount, nil
+}
+
+// mkGteRange determines if the range end is a >= range. This works around grpc
+// sending empty byte strings as nil; >= is encoded in the range end as '\0'.
+// If it is a GTE range, then []byte{} is returned to indicate the empty byte
+// string (vs nil being no byte string).
+func mkGteRange(rangeEnd []byte) []byte {
+	if len(rangeEnd) == 1 && rangeEnd[0] == 0 {
+		return []byte{}
+	}
+	return rangeEnd
+}
+
+func pruneKVs(rr *mvcc.RangeResult, isPrunable func(*mvccpb.KeyValue) bool) {
+	j := 0
+	for i := range rr.KVs {
+		rr.KVs[j] = rr.KVs[i]
+		if !isPrunable(&rr.KVs[i]) {
+			j++
+		}
+	}
+	rr.KVs = rr.KVs[:j]
+}
+
+type kvSort struct{ kvs []mvccpb.KeyValue }
+
+func (s *kvSort) Swap(i, j int) {
+	t := s.kvs[i]
+	s.kvs[i] = s.kvs[j]
+	s.kvs[j] = t
+}
+func (s *kvSort) Len() int { return len(s.kvs) }
+
+type kvSortByKey struct{ *kvSort }
+
+func (s *kvSortByKey) Less(i, j int) bool {
+	return bytes.Compare(s.kvs[i].Key, s.kvs[j].Key) < 0
+}
+
+type kvSortByVersion struct{ *kvSort }
+
+func (s *kvSortByVersion) Less(i, j int) bool {
+	return (s.kvs[i].Version - s.kvs[j].Version) < 0
+}
+
+type kvSortByCreate struct{ *kvSort }
+
+func (s *kvSortByCreate) Less(i, j int) bool {
+	return (s.kvs[i].CreateRevision - s.kvs[j].CreateRevision) < 0
+}
+
+type kvSortByMod struct{ *kvSort }
+
+func (s *kvSortByMod) Less(i, j int) bool {
+	return (s.kvs[i].ModRevision - s.kvs[j].ModRevision) < 0
+}
+
+type kvSortByValue struct{ *kvSort }
+
+func (s *kvSortByValue) Less(i, j int) bool {
+	return bytes.Compare(s.kvs[i].Value, s.kvs[j].Value) < 0
+}
+
+func compareInt64(a, b int64) int {
+	switch {
+	case a < b:
+		return -1
+	case a > b:
+		return 1
+	default:
+		return 0
+	}
+}
+
+func compareToPath(rv mvcc.ReadView, rt *pb.TxnRequest) []bool {
+	txnPath := make([]bool, 1)
+	ops := rt.Success
+	if txnPath[0] = applyCompares(rv, rt.Compare); !txnPath[0] {
+		ops = rt.Failure
+	}
+	for _, op := range ops {
+		tv, ok := op.Request.(*pb.RequestOp_RequestTxn)
+		if !ok || tv.RequestTxn == nil {
+			continue
+		}
+		txnPath = append(txnPath, compareToPath(rv, tv.RequestTxn)...)
+	}
+	return txnPath
+}
+
+func applyCompares(rv mvcc.ReadView, cmps []*pb.Compare) bool {
+	for _, c := range cmps {
+		if !applyCompare(rv, c) {
+			return false
+		}
+	}
+	return true
+}
+
+// applyCompare applies the compare request.
+// If the comparison succeeds, it returns true. Otherwise, returns false.
+func applyCompare(rv mvcc.ReadView, c *pb.Compare) bool {
+	// TODO: possible optimizations
+	// * chunk reads for large ranges to conserve memory
+	// * rewrite rules for common patterns:
+	//	ex. "[a, b) createrev > 0" => "limit 1 /\ kvs > 0"
+	// * caching
+	rr, err := rv.Range(context.TODO(), c.Key, mkGteRange(c.RangeEnd), mvcc.RangeOptions{})
+	if err != nil {
+		return false
+	}
+	if len(rr.KVs) == 0 {
+		if c.Target == pb.Compare_VALUE {
+			// Always fail if comparing a value on a key/keys that doesn't exist;
+			// nil == empty string in grpc; no way to represent missing value
+			return false
+		}
+		return compareKV(c, mvccpb.KeyValue{})
+	}
+	for _, kv := range rr.KVs {
+		if !compareKV(c, kv) {
+			return false
+		}
+	}
+	return true
+}
+
+func compareKV(c *pb.Compare, ckv mvccpb.KeyValue) bool {
+	var result int
+	rev := int64(0)
+	switch c.Target {
+	case pb.Compare_VALUE:
+		var v []byte
+		if tv, _ := c.TargetUnion.(*pb.Compare_Value); tv != nil {
+			v = tv.Value
+		}
+		result = bytes.Compare(ckv.Value, v)
+	case pb.Compare_CREATE:
+		if tv, _ := c.TargetUnion.(*pb.Compare_CreateRevision); tv != nil {
+			rev = tv.CreateRevision
+		}
+		result = compareInt64(ckv.CreateRevision, rev)
+	case pb.Compare_MOD:
+		if tv, _ := c.TargetUnion.(*pb.Compare_ModRevision); tv != nil {
+			rev = tv.ModRevision
+		}
+		result = compareInt64(ckv.ModRevision, rev)
+	case pb.Compare_VERSION:
+		if tv, _ := c.TargetUnion.(*pb.Compare_Version); tv != nil {
+			rev = tv.Version
+		}
+		result = compareInt64(ckv.Version, rev)
+	case pb.Compare_LEASE:
+		if tv, _ := c.TargetUnion.(*pb.Compare_Lease); tv != nil {
+			rev = tv.Lease
+		}
+		result = compareInt64(ckv.Lease, rev)
+	}
+	switch c.Result {
+	case pb.Compare_EQUAL:
+		return result == 0
+	case pb.Compare_NOT_EQUAL:
+		return result != 0
+	case pb.Compare_GREATER:
+		return result > 0
+	case pb.Compare_LESS:
+		return result < 0
+	}
+	return true
+}
+
+func IsTxnSerializable(r *pb.TxnRequest) bool {
+	for _, u := range r.Success {
+		if r := u.GetRequestRange(); r == nil || !r.Serializable {
+			return false
+		}
+	}
+	for _, u := range r.Failure {
+		if r := u.GetRequestRange(); r == nil || !r.Serializable {
+			return false
+		}
+	}
+	return true
+}
+
+func IsTxnReadonly(r *pb.TxnRequest) bool {
+	for _, u := range r.Success {
+		if r := u.GetRequestRange(); r == nil {
+			return false
+		}
+	}
+	for _, u := range r.Failure {
+		if r := u.GetRequestRange(); r == nil {
+			return false
+		}
+	}
+	return true
+}
+
+func CheckTxnAuth(as auth.AuthStore, ai *auth.AuthInfo, rt *pb.TxnRequest) error {
+	for _, c := range rt.Compare {
+		if err := as.IsRangePermitted(ai, c.Key, c.RangeEnd); err != nil {
+			return err
+		}
+	}
+	if err := checkTxnReqsPermission(as, ai, rt.Success); err != nil {
+		return err
+	}
+	return checkTxnReqsPermission(as, ai, rt.Failure)
+}
+
+func checkTxnReqsPermission(as auth.AuthStore, ai *auth.AuthInfo, reqs []*pb.RequestOp) error {
+	for _, requ := range reqs {
+		switch tv := requ.Request.(type) {
+		case *pb.RequestOp_RequestRange:
+			if tv.RequestRange == nil {
+				continue
+			}
+
+			if err := as.IsRangePermitted(ai, tv.RequestRange.Key, tv.RequestRange.RangeEnd); err != nil {
+				return err
+			}
+
+		case *pb.RequestOp_RequestPut:
+			if tv.RequestPut == nil {
+				continue
+			}
+
+			if err := as.IsPutPermitted(ai, tv.RequestPut.Key); err != nil {
+				return err
+			}
+
+		case *pb.RequestOp_RequestDeleteRange:
+			if tv.RequestDeleteRange == nil {
+				continue
+			}
+
+			if tv.RequestDeleteRange.PrevKv {
+				err := as.IsRangePermitted(ai, tv.RequestDeleteRange.Key, tv.RequestDeleteRange.RangeEnd)
+				if err != nil {
+					return err
+				}
+			}
+
+			err := as.IsDeleteRangePermitted(ai, tv.RequestDeleteRange.Key, tv.RequestDeleteRange.RangeEnd)
+			if err != nil {
+				return err
+			}
+		}
+	}
+
+	return nil
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/txn/util.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/txn/util.go
new file mode 100644
index 0000000..f9987c6
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/txn/util.go
@@ -0,0 +1,107 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package txn
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+	"time"
+
+	"github.com/golang/protobuf/proto"
+	"go.uber.org/zap"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+)
+
+func WarnOfExpensiveRequest(lg *zap.Logger, warningApplyDuration time.Duration, now time.Time, reqStringer fmt.Stringer, respMsg proto.Message, err error) {
+	if time.Since(now) <= warningApplyDuration {
+		return
+	}
+	var resp string
+	if !isNil(respMsg) {
+		resp = fmt.Sprintf("size:%d", proto.Size(respMsg))
+	}
+	warnOfExpensiveGenericRequest(lg, warningApplyDuration, now, reqStringer, "", resp, err)
+}
+
+func WarnOfFailedRequest(lg *zap.Logger, now time.Time, reqStringer fmt.Stringer, respMsg proto.Message, err error) {
+	var resp string
+	if !isNil(respMsg) {
+		resp = fmt.Sprintf("size:%d", proto.Size(respMsg))
+	}
+	d := time.Since(now)
+	lg.Warn(
+		"failed to apply request",
+		zap.Duration("took", d),
+		zap.String("request", reqStringer.String()),
+		zap.String("response", resp),
+		zap.Error(err),
+	)
+}
+
+func WarnOfExpensiveReadOnlyTxnRequest(lg *zap.Logger, warningApplyDuration time.Duration, now time.Time, r *pb.TxnRequest, txnResponse *pb.TxnResponse, err error) {
+	if time.Since(now) <= warningApplyDuration {
+		return
+	}
+	reqStringer := pb.NewLoggableTxnRequest(r)
+	var resp string
+	if !isNil(txnResponse) {
+		var resps []string
+		for _, r := range txnResponse.Responses {
+			switch r.Response.(type) {
+			case *pb.ResponseOp_ResponseRange:
+				if op := r.GetResponseRange(); op != nil {
+					resps = append(resps, fmt.Sprintf("range_response_count:%d", len(op.GetKvs())))
+				} else {
+					resps = append(resps, "range_response:nil")
+				}
+			default:
+				// only range responses should be in a read only txn request
+			}
+		}
+		resp = fmt.Sprintf("responses:<%s> size:%d", strings.Join(resps, " "), txnResponse.Size())
+	}
+	warnOfExpensiveGenericRequest(lg, warningApplyDuration, now, reqStringer, "read-only txn ", resp, err)
+}
+
+func WarnOfExpensiveReadOnlyRangeRequest(lg *zap.Logger, warningApplyDuration time.Duration, now time.Time, reqStringer fmt.Stringer, rangeResponse *pb.RangeResponse, err error) {
+	if time.Since(now) <= warningApplyDuration {
+		return
+	}
+	var resp string
+	if !isNil(rangeResponse) {
+		resp = fmt.Sprintf("range_response_count:%d size:%d", len(rangeResponse.Kvs), rangeResponse.Size())
+	}
+	warnOfExpensiveGenericRequest(lg, warningApplyDuration, now, reqStringer, "read-only range ", resp, err)
+}
+
+// callers need make sure time has passed warningApplyDuration
+func warnOfExpensiveGenericRequest(lg *zap.Logger, warningApplyDuration time.Duration, now time.Time, reqStringer fmt.Stringer, prefix string, resp string, err error) {
+	lg.Warn(
+		"apply request took too long",
+		zap.Duration("took", time.Since(now)),
+		zap.Duration("expected-duration", warningApplyDuration),
+		zap.String("prefix", prefix),
+		zap.String("request", reqStringer.String()),
+		zap.String("response", resp),
+		zap.Error(err),
+	)
+	slowApplies.Inc()
+}
+
+func isNil(msg proto.Message) bool {
+	return msg == nil || reflect.ValueOf(msg).IsNil()
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/util.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/util.go
new file mode 100644
index 0000000..fbba549
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/util.go
@@ -0,0 +1,116 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package etcdserver
+
+import (
+	"fmt"
+	"time"
+
+	"go.etcd.io/etcd/client/pkg/v3/types"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/membership"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/rafthttp"
+)
+
+// isConnectedToQuorumSince checks whether the local member is connected to the
+// quorum of the cluster since the given time.
+func isConnectedToQuorumSince(transport rafthttp.Transporter, since time.Time, self types.ID, members []*membership.Member) bool {
+	return numConnectedSince(transport, since, self, members) >= (len(members)/2)+1
+}
+
+// isConnectedSince checks whether the local member is connected to the
+// remote member since the given time.
+func isConnectedSince(transport rafthttp.Transporter, since time.Time, remote types.ID) bool {
+	t := transport.ActiveSince(remote)
+	return !t.IsZero() && t.Before(since)
+}
+
+// isConnectedFullySince checks whether the local member is connected to all
+// members in the cluster since the given time.
+func isConnectedFullySince(transport rafthttp.Transporter, since time.Time, self types.ID, members []*membership.Member) bool {
+	return numConnectedSince(transport, since, self, members) == len(members)
+}
+
+// numConnectedSince counts how many members are connected to the local member
+// since the given time.
+func numConnectedSince(transport rafthttp.Transporter, since time.Time, self types.ID, members []*membership.Member) int {
+	connectedNum := 0
+	for _, m := range members {
+		if m.ID == self || isConnectedSince(transport, since, m.ID) {
+			connectedNum++
+		}
+	}
+	return connectedNum
+}
+
+// longestConnected chooses the member with longest active-since-time.
+// It returns false, if nothing is active.
+func longestConnected(tp rafthttp.Transporter, membs []types.ID) (types.ID, bool) {
+	var longest types.ID
+	var oldest time.Time
+	for _, id := range membs {
+		tm := tp.ActiveSince(id)
+		if tm.IsZero() { // inactive
+			continue
+		}
+
+		if oldest.IsZero() { // first longest candidate
+			oldest = tm
+			longest = id
+		}
+
+		if tm.Before(oldest) {
+			oldest = tm
+			longest = id
+		}
+	}
+	if uint64(longest) == 0 {
+		return longest, false
+	}
+	return longest, true
+}
+
+type notifier struct {
+	c   chan struct{}
+	err error
+}
+
+func newNotifier() *notifier {
+	return &notifier{
+		c: make(chan struct{}),
+	}
+}
+
+func (nc *notifier) notify(err error) {
+	nc.err = err
+	close(nc.c)
+}
+
+// panicAlternativeStringer wraps a fmt.Stringer, and if calling String() panics, calls the alternative instead.
+// This is needed to ensure logging slow v2 requests does not panic, which occurs when running integration tests
+// with the embedded server with github.com/golang/protobuf v1.4.0+. See https://github.com/etcd-io/etcd/issues/12197.
+type panicAlternativeStringer struct {
+	stringer    fmt.Stringer
+	alternative func() string
+}
+
+func (n panicAlternativeStringer) String() (s string) {
+	defer func() {
+		if err := recover(); err != nil {
+			s = n.alternative()
+		}
+	}()
+	s = n.stringer.String()
+	return s
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/v2_server.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/v2_server.go
new file mode 100644
index 0000000..8636204
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/v2_server.go
@@ -0,0 +1,26 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package etcdserver
+
+import (
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+)
+
+type RequestV2 pb.Request
+
+func (r *RequestV2) String() string {
+	rpb := pb.Request(*r)
+	return rpb.String()
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/v3_server.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/v3_server.go
new file mode 100644
index 0000000..c695360
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/v3_server.go
@@ -0,0 +1,1054 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package etcdserver
+
+import (
+	"bytes"
+	"context"
+	"encoding/base64"
+	"encoding/binary"
+	errorspkg "errors"
+	"strconv"
+	"time"
+
+	"github.com/gogo/protobuf/proto"
+	"go.uber.org/zap"
+	"golang.org/x/crypto/bcrypt"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/api/v3/version"
+	"go.etcd.io/etcd/pkg/v3/traceutil"
+	"go.etcd.io/etcd/server/v3/auth"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/membership"
+	apply2 "go.etcd.io/etcd/server/v3/etcdserver/apply"
+	"go.etcd.io/etcd/server/v3/etcdserver/errors"
+	"go.etcd.io/etcd/server/v3/etcdserver/txn"
+	"go.etcd.io/etcd/server/v3/features"
+	"go.etcd.io/etcd/server/v3/lease"
+	"go.etcd.io/etcd/server/v3/lease/leasehttp"
+	"go.etcd.io/etcd/server/v3/storage/mvcc"
+	"go.etcd.io/raft/v3"
+)
+
+const (
+	// In the health case, there might be a small gap (10s of entries) between
+	// the applied index and committed index.
+	// However, if the committed entries are very heavy to toApply, the gap might grow.
+	// We should stop accepting new proposals if the gap growing to a certain point.
+	maxGapBetweenApplyAndCommitIndex = 5000
+	traceThreshold                   = 100 * time.Millisecond
+	readIndexRetryTime               = 500 * time.Millisecond
+
+	// The timeout for the node to catch up its applied index, and is used in
+	// lease related operations, such as LeaseRenew and LeaseTimeToLive.
+	applyTimeout = time.Second
+)
+
+type RaftKV interface {
+	Range(ctx context.Context, r *pb.RangeRequest) (*pb.RangeResponse, error)
+	Put(ctx context.Context, r *pb.PutRequest) (*pb.PutResponse, error)
+	DeleteRange(ctx context.Context, r *pb.DeleteRangeRequest) (*pb.DeleteRangeResponse, error)
+	Txn(ctx context.Context, r *pb.TxnRequest) (*pb.TxnResponse, error)
+	Compact(ctx context.Context, r *pb.CompactionRequest) (*pb.CompactionResponse, error)
+}
+
+type Lessor interface {
+	// LeaseGrant sends LeaseGrant request to raft and toApply it after committed.
+	LeaseGrant(ctx context.Context, r *pb.LeaseGrantRequest) (*pb.LeaseGrantResponse, error)
+	// LeaseRevoke sends LeaseRevoke request to raft and toApply it after committed.
+	LeaseRevoke(ctx context.Context, r *pb.LeaseRevokeRequest) (*pb.LeaseRevokeResponse, error)
+
+	// LeaseRenew renews the lease with given ID. The renewed TTL is returned. Or an error
+	// is returned.
+	LeaseRenew(ctx context.Context, id lease.LeaseID) (int64, error)
+
+	// LeaseTimeToLive retrieves lease information.
+	LeaseTimeToLive(ctx context.Context, r *pb.LeaseTimeToLiveRequest) (*pb.LeaseTimeToLiveResponse, error)
+
+	// LeaseLeases lists all leases.
+	LeaseLeases(ctx context.Context, r *pb.LeaseLeasesRequest) (*pb.LeaseLeasesResponse, error)
+}
+
+type Authenticator interface {
+	AuthEnable(ctx context.Context, r *pb.AuthEnableRequest) (*pb.AuthEnableResponse, error)
+	AuthDisable(ctx context.Context, r *pb.AuthDisableRequest) (*pb.AuthDisableResponse, error)
+	AuthStatus(ctx context.Context, r *pb.AuthStatusRequest) (*pb.AuthStatusResponse, error)
+	Authenticate(ctx context.Context, r *pb.AuthenticateRequest) (*pb.AuthenticateResponse, error)
+	UserAdd(ctx context.Context, r *pb.AuthUserAddRequest) (*pb.AuthUserAddResponse, error)
+	UserDelete(ctx context.Context, r *pb.AuthUserDeleteRequest) (*pb.AuthUserDeleteResponse, error)
+	UserChangePassword(ctx context.Context, r *pb.AuthUserChangePasswordRequest) (*pb.AuthUserChangePasswordResponse, error)
+	UserGrantRole(ctx context.Context, r *pb.AuthUserGrantRoleRequest) (*pb.AuthUserGrantRoleResponse, error)
+	UserGet(ctx context.Context, r *pb.AuthUserGetRequest) (*pb.AuthUserGetResponse, error)
+	UserRevokeRole(ctx context.Context, r *pb.AuthUserRevokeRoleRequest) (*pb.AuthUserRevokeRoleResponse, error)
+	RoleAdd(ctx context.Context, r *pb.AuthRoleAddRequest) (*pb.AuthRoleAddResponse, error)
+	RoleGrantPermission(ctx context.Context, r *pb.AuthRoleGrantPermissionRequest) (*pb.AuthRoleGrantPermissionResponse, error)
+	RoleGet(ctx context.Context, r *pb.AuthRoleGetRequest) (*pb.AuthRoleGetResponse, error)
+	RoleRevokePermission(ctx context.Context, r *pb.AuthRoleRevokePermissionRequest) (*pb.AuthRoleRevokePermissionResponse, error)
+	RoleDelete(ctx context.Context, r *pb.AuthRoleDeleteRequest) (*pb.AuthRoleDeleteResponse, error)
+	UserList(ctx context.Context, r *pb.AuthUserListRequest) (*pb.AuthUserListResponse, error)
+	RoleList(ctx context.Context, r *pb.AuthRoleListRequest) (*pb.AuthRoleListResponse, error)
+}
+
+func (s *EtcdServer) Range(ctx context.Context, r *pb.RangeRequest) (*pb.RangeResponse, error) {
+	trace := traceutil.New("range",
+		s.Logger(),
+		traceutil.Field{Key: "range_begin", Value: string(r.Key)},
+		traceutil.Field{Key: "range_end", Value: string(r.RangeEnd)},
+	)
+	ctx = context.WithValue(ctx, traceutil.TraceKey{}, trace)
+
+	var resp *pb.RangeResponse
+	var err error
+	defer func(start time.Time) {
+		txn.WarnOfExpensiveReadOnlyRangeRequest(s.Logger(), s.Cfg.WarningApplyDuration, start, r, resp, err)
+		if resp != nil {
+			trace.AddField(
+				traceutil.Field{Key: "response_count", Value: len(resp.Kvs)},
+				traceutil.Field{Key: "response_revision", Value: resp.Header.Revision},
+			)
+		}
+		trace.LogIfLong(traceThreshold)
+	}(time.Now())
+
+	if !r.Serializable {
+		err = s.linearizableReadNotify(ctx)
+		trace.Step("agreement among raft nodes before linearized reading")
+		if err != nil {
+			return nil, err
+		}
+	}
+	chk := func(ai *auth.AuthInfo) error {
+		return s.authStore.IsRangePermitted(ai, r.Key, r.RangeEnd)
+	}
+
+	get := func() { resp, _, err = txn.Range(ctx, s.Logger(), s.KV(), r) }
+	if serr := s.doSerialize(ctx, chk, get); serr != nil {
+		err = serr
+		return nil, err
+	}
+	return resp, err
+}
+
+func (s *EtcdServer) Put(ctx context.Context, r *pb.PutRequest) (*pb.PutResponse, error) {
+	ctx = context.WithValue(ctx, traceutil.StartTimeKey{}, time.Now())
+	resp, err := s.raftRequest(ctx, pb.InternalRaftRequest{Put: r})
+	if err != nil {
+		return nil, err
+	}
+	return resp.(*pb.PutResponse), nil
+}
+
+func (s *EtcdServer) DeleteRange(ctx context.Context, r *pb.DeleteRangeRequest) (*pb.DeleteRangeResponse, error) {
+	resp, err := s.raftRequest(ctx, pb.InternalRaftRequest{DeleteRange: r})
+	if err != nil {
+		return nil, err
+	}
+	return resp.(*pb.DeleteRangeResponse), nil
+}
+
+func (s *EtcdServer) Txn(ctx context.Context, r *pb.TxnRequest) (*pb.TxnResponse, error) {
+	if txn.IsTxnReadonly(r) {
+		trace := traceutil.New("transaction",
+			s.Logger(),
+			traceutil.Field{Key: "read_only", Value: true},
+		)
+		ctx = context.WithValue(ctx, traceutil.TraceKey{}, trace)
+		if !txn.IsTxnSerializable(r) {
+			err := s.linearizableReadNotify(ctx)
+			trace.Step("agreement among raft nodes before linearized reading")
+			if err != nil {
+				return nil, err
+			}
+		}
+		var resp *pb.TxnResponse
+		var err error
+		chk := func(ai *auth.AuthInfo) error {
+			return txn.CheckTxnAuth(s.authStore, ai, r)
+		}
+
+		defer func(start time.Time) {
+			txn.WarnOfExpensiveReadOnlyTxnRequest(s.Logger(), s.Cfg.WarningApplyDuration, start, r, resp, err)
+			trace.LogIfLong(traceThreshold)
+		}(time.Now())
+
+		get := func() {
+			resp, _, err = txn.Txn(ctx, s.Logger(), r, s.Cfg.ServerFeatureGate.Enabled(features.TxnModeWriteWithSharedBuffer), s.KV(), s.lessor)
+		}
+		if serr := s.doSerialize(ctx, chk, get); serr != nil {
+			return nil, serr
+		}
+		return resp, err
+	}
+
+	ctx = context.WithValue(ctx, traceutil.StartTimeKey{}, time.Now())
+	resp, err := s.raftRequest(ctx, pb.InternalRaftRequest{Txn: r})
+	if err != nil {
+		return nil, err
+	}
+	return resp.(*pb.TxnResponse), nil
+}
+
+func (s *EtcdServer) Compact(ctx context.Context, r *pb.CompactionRequest) (*pb.CompactionResponse, error) {
+	startTime := time.Now()
+	result, err := s.processInternalRaftRequestOnce(ctx, pb.InternalRaftRequest{Compaction: r})
+	trace := traceutil.TODO()
+	if result != nil && result.Trace != nil {
+		trace = result.Trace
+		defer func() {
+			trace.LogIfLong(traceThreshold)
+		}()
+		applyStart := result.Trace.GetStartTime()
+		result.Trace.SetStartTime(startTime)
+		trace.InsertStep(0, applyStart, "process raft request")
+	}
+	if r.Physical && result != nil && result.Physc != nil {
+		<-result.Physc
+		// The compaction is done deleting keys; the hash is now settled
+		// but the data is not necessarily committed. If there's a crash,
+		// the hash may revert to a hash prior to compaction completing
+		// if the compaction resumes. Force the finished compaction to
+		// commit so it won't resume following a crash.
+		//
+		// `applySnapshot` sets a new backend instance, so we need to acquire the bemu lock.
+		s.bemu.RLock()
+		s.be.ForceCommit()
+		s.bemu.RUnlock()
+		trace.Step("physically toApply compaction")
+	}
+	if err != nil {
+		return nil, err
+	}
+	if result.Err != nil {
+		return nil, result.Err
+	}
+	resp := result.Resp.(*pb.CompactionResponse)
+	if resp == nil {
+		resp = &pb.CompactionResponse{}
+	}
+	if resp.Header == nil {
+		resp.Header = &pb.ResponseHeader{}
+	}
+	resp.Header.Revision = s.kv.Rev()
+	trace.AddField(traceutil.Field{Key: "response_revision", Value: resp.Header.Revision})
+	return resp, nil
+}
+
+func (s *EtcdServer) LeaseGrant(ctx context.Context, r *pb.LeaseGrantRequest) (*pb.LeaseGrantResponse, error) {
+	// no id given? choose one
+	for r.ID == int64(lease.NoLease) {
+		// only use positive int64 id's
+		r.ID = int64(s.reqIDGen.Next() & ((1 << 63) - 1))
+	}
+	resp, err := s.raftRequestOnce(ctx, pb.InternalRaftRequest{LeaseGrant: r})
+	if err != nil {
+		return nil, err
+	}
+	return resp.(*pb.LeaseGrantResponse), nil
+}
+
+func (s *EtcdServer) waitAppliedIndex() error {
+	select {
+	case <-s.ApplyWait():
+	case <-s.stopping:
+		return errors.ErrStopped
+	case <-time.After(applyTimeout):
+		return errors.ErrTimeoutWaitAppliedIndex
+	}
+
+	return nil
+}
+
+func (s *EtcdServer) LeaseRevoke(ctx context.Context, r *pb.LeaseRevokeRequest) (*pb.LeaseRevokeResponse, error) {
+	resp, err := s.raftRequestOnce(ctx, pb.InternalRaftRequest{LeaseRevoke: r})
+	if err != nil {
+		return nil, err
+	}
+	return resp.(*pb.LeaseRevokeResponse), nil
+}
+
+func (s *EtcdServer) LeaseRenew(ctx context.Context, id lease.LeaseID) (int64, error) {
+	if s.isLeader() {
+		// If s.isLeader() returns true, but we fail to ensure the current
+		// member's leadership, there are a couple of possibilities:
+		//   1. current member gets stuck on writing WAL entries;
+		//   2. current member is in network isolation status;
+		//   3. current member isn't a leader anymore (possibly due to #1 above).
+		// In such case, we just return error to client, so that the client can
+		// switch to another member to continue the lease keep-alive operation.
+		if !s.ensureLeadership() {
+			return -1, lease.ErrNotPrimary
+		}
+		if err := s.waitAppliedIndex(); err != nil {
+			return 0, err
+		}
+
+		ttl, err := s.lessor.Renew(id)
+		if err == nil { // already requested to primary lessor(leader)
+			return ttl, nil
+		}
+		if !errorspkg.Is(err, lease.ErrNotPrimary) {
+			return -1, err
+		}
+	}
+
+	cctx, cancel := context.WithTimeout(ctx, s.Cfg.ReqTimeout())
+	defer cancel()
+
+	// renewals don't go through raft; forward to leader manually
+	for cctx.Err() == nil {
+		leader, lerr := s.waitLeader(cctx)
+		if lerr != nil {
+			return -1, lerr
+		}
+		for _, url := range leader.PeerURLs {
+			lurl := url + leasehttp.LeasePrefix
+			ttl, err := leasehttp.RenewHTTP(cctx, id, lurl, s.peerRt)
+			if err == nil || errorspkg.Is(err, lease.ErrLeaseNotFound) {
+				return ttl, err
+			}
+		}
+		// Throttle in case of e.g. connection problems.
+		time.Sleep(50 * time.Millisecond)
+	}
+
+	if errorspkg.Is(cctx.Err(), context.DeadlineExceeded) {
+		return -1, errors.ErrTimeout
+	}
+	return -1, errors.ErrCanceled
+}
+
+func (s *EtcdServer) checkLeaseTimeToLive(ctx context.Context, leaseID lease.LeaseID) (uint64, error) {
+	rev := s.AuthStore().Revision()
+	if !s.AuthStore().IsAuthEnabled() {
+		return rev, nil
+	}
+	authInfo, err := s.AuthInfoFromCtx(ctx)
+	if err != nil {
+		return rev, err
+	}
+	if authInfo == nil {
+		return rev, auth.ErrUserEmpty
+	}
+
+	l := s.lessor.Lookup(leaseID)
+	if l != nil {
+		for _, key := range l.Keys() {
+			if err := s.AuthStore().IsRangePermitted(authInfo, []byte(key), []byte{}); err != nil {
+				return 0, err
+			}
+		}
+	}
+
+	return rev, nil
+}
+
+func (s *EtcdServer) leaseTimeToLive(ctx context.Context, r *pb.LeaseTimeToLiveRequest) (*pb.LeaseTimeToLiveResponse, error) {
+	if s.isLeader() {
+		if err := s.waitAppliedIndex(); err != nil {
+			return nil, err
+		}
+
+		// gofail: var beforeLookupWhenLeaseTimeToLive struct{}
+
+		// primary; timetolive directly from leader
+		le := s.lessor.Lookup(lease.LeaseID(r.ID))
+		if le == nil {
+			return nil, lease.ErrLeaseNotFound
+		}
+		// TODO: fill out ResponseHeader
+		resp := &pb.LeaseTimeToLiveResponse{Header: &pb.ResponseHeader{}, ID: r.ID, TTL: int64(le.Remaining().Seconds()), GrantedTTL: le.TTL()}
+		if r.Keys {
+			ks := le.Keys()
+			kbs := make([][]byte, len(ks))
+			for i := range ks {
+				kbs[i] = []byte(ks[i])
+			}
+			resp.Keys = kbs
+		}
+
+		// The leasor could be demoted if leader changed during lookup.
+		// We should return error to force retry instead of returning
+		// incorrect remaining TTL.
+		if le.Demoted() {
+			// NOTE: lease.ErrNotPrimary is not retryable error for
+			// client. Instead, uses ErrLeaderChanged.
+			return nil, errors.ErrLeaderChanged
+		}
+		return resp, nil
+	}
+
+	cctx, cancel := context.WithTimeout(ctx, s.Cfg.ReqTimeout())
+	defer cancel()
+
+	// forward to leader
+	for cctx.Err() == nil {
+		leader, err := s.waitLeader(cctx)
+		if err != nil {
+			return nil, err
+		}
+		for _, url := range leader.PeerURLs {
+			lurl := url + leasehttp.LeaseInternalPrefix
+			resp, err := leasehttp.TimeToLiveHTTP(cctx, lease.LeaseID(r.ID), r.Keys, lurl, s.peerRt)
+			if err == nil {
+				return resp.LeaseTimeToLiveResponse, nil
+			}
+			if errorspkg.Is(err, lease.ErrLeaseNotFound) {
+				return nil, err
+			}
+		}
+	}
+
+	if errorspkg.Is(cctx.Err(), context.DeadlineExceeded) {
+		return nil, errors.ErrTimeout
+	}
+	return nil, errors.ErrCanceled
+}
+
+func (s *EtcdServer) LeaseTimeToLive(ctx context.Context, r *pb.LeaseTimeToLiveRequest) (*pb.LeaseTimeToLiveResponse, error) {
+	var rev uint64
+	var err error
+	if r.Keys {
+		// check RBAC permission only if Keys is true
+		rev, err = s.checkLeaseTimeToLive(ctx, lease.LeaseID(r.ID))
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	resp, err := s.leaseTimeToLive(ctx, r)
+	if err != nil {
+		return nil, err
+	}
+
+	if r.Keys {
+		if s.AuthStore().IsAuthEnabled() && rev != s.AuthStore().Revision() {
+			return nil, auth.ErrAuthOldRevision
+		}
+	}
+	return resp, nil
+}
+
+func (s *EtcdServer) newHeader() *pb.ResponseHeader {
+	return &pb.ResponseHeader{
+		ClusterId: uint64(s.cluster.ID()),
+		MemberId:  uint64(s.MemberID()),
+		Revision:  s.KV().Rev(),
+		RaftTerm:  s.Term(),
+	}
+}
+
+// LeaseLeases is really ListLeases !???
+func (s *EtcdServer) LeaseLeases(_ context.Context, _ *pb.LeaseLeasesRequest) (*pb.LeaseLeasesResponse, error) {
+	ls := s.lessor.Leases()
+	lss := make([]*pb.LeaseStatus, len(ls))
+	for i := range ls {
+		lss[i] = &pb.LeaseStatus{ID: int64(ls[i].ID)}
+	}
+	return &pb.LeaseLeasesResponse{Header: s.newHeader(), Leases: lss}, nil
+}
+
+func (s *EtcdServer) waitLeader(ctx context.Context) (*membership.Member, error) {
+	leader := s.cluster.Member(s.Leader())
+	for leader == nil {
+		// wait an election
+		dur := time.Duration(s.Cfg.ElectionTicks) * time.Duration(s.Cfg.TickMs) * time.Millisecond
+		select {
+		case <-time.After(dur):
+			leader = s.cluster.Member(s.Leader())
+		case <-s.stopping:
+			return nil, errors.ErrStopped
+		case <-ctx.Done():
+			return nil, errors.ErrNoLeader
+		}
+	}
+	if len(leader.PeerURLs) == 0 {
+		return nil, errors.ErrNoLeader
+	}
+	return leader, nil
+}
+
+func (s *EtcdServer) Alarm(ctx context.Context, r *pb.AlarmRequest) (*pb.AlarmResponse, error) {
+	resp, err := s.raftRequestOnce(ctx, pb.InternalRaftRequest{Alarm: r})
+	if err != nil {
+		return nil, err
+	}
+	return resp.(*pb.AlarmResponse), nil
+}
+
+func (s *EtcdServer) AuthEnable(ctx context.Context, r *pb.AuthEnableRequest) (*pb.AuthEnableResponse, error) {
+	resp, err := s.raftRequestOnce(ctx, pb.InternalRaftRequest{AuthEnable: r})
+	if err != nil {
+		return nil, err
+	}
+	return resp.(*pb.AuthEnableResponse), nil
+}
+
+func (s *EtcdServer) AuthDisable(ctx context.Context, r *pb.AuthDisableRequest) (*pb.AuthDisableResponse, error) {
+	resp, err := s.raftRequest(ctx, pb.InternalRaftRequest{AuthDisable: r})
+	if err != nil {
+		return nil, err
+	}
+	return resp.(*pb.AuthDisableResponse), nil
+}
+
+func (s *EtcdServer) AuthStatus(ctx context.Context, r *pb.AuthStatusRequest) (*pb.AuthStatusResponse, error) {
+	resp, err := s.raftRequest(ctx, pb.InternalRaftRequest{AuthStatus: r})
+	if err != nil {
+		return nil, err
+	}
+	return resp.(*pb.AuthStatusResponse), nil
+}
+
+func (s *EtcdServer) Authenticate(ctx context.Context, r *pb.AuthenticateRequest) (*pb.AuthenticateResponse, error) {
+	if err := s.linearizableReadNotify(ctx); err != nil {
+		return nil, err
+	}
+
+	lg := s.Logger()
+
+	// fix https://nvd.nist.gov/vuln/detail/CVE-2021-28235
+	defer func() {
+		if r != nil {
+			r.Password = ""
+		}
+	}()
+
+	var resp proto.Message
+	for {
+		checkedRevision, err := s.AuthStore().CheckPassword(r.Name, r.Password)
+		if err != nil {
+			if !errorspkg.Is(err, auth.ErrAuthNotEnabled) {
+				lg.Warn(
+					"invalid authentication was requested",
+					zap.String("user", r.Name),
+					zap.Error(err),
+				)
+			}
+			return nil, err
+		}
+
+		st, err := s.AuthStore().GenTokenPrefix()
+		if err != nil {
+			return nil, err
+		}
+
+		// internalReq doesn't need to have Password because the above s.AuthStore().CheckPassword() already did it.
+		// In addition, it will let a WAL entry not record password as a plain text.
+		internalReq := &pb.InternalAuthenticateRequest{
+			Name:        r.Name,
+			SimpleToken: st,
+		}
+
+		resp, err = s.raftRequestOnce(ctx, pb.InternalRaftRequest{Authenticate: internalReq})
+		if err != nil {
+			return nil, err
+		}
+		if checkedRevision == s.AuthStore().Revision() {
+			break
+		}
+
+		lg.Info("revision when password checked became stale; retrying")
+	}
+
+	return resp.(*pb.AuthenticateResponse), nil
+}
+
+func (s *EtcdServer) UserAdd(ctx context.Context, r *pb.AuthUserAddRequest) (*pb.AuthUserAddResponse, error) {
+	if r.Options == nil || !r.Options.NoPassword {
+		hashedPassword, err := bcrypt.GenerateFromPassword([]byte(r.Password), s.authStore.BcryptCost())
+		if err != nil {
+			return nil, err
+		}
+		r.HashedPassword = base64.StdEncoding.EncodeToString(hashedPassword)
+		r.Password = ""
+	}
+
+	resp, err := s.raftRequest(ctx, pb.InternalRaftRequest{AuthUserAdd: r})
+	if err != nil {
+		return nil, err
+	}
+	return resp.(*pb.AuthUserAddResponse), nil
+}
+
+func (s *EtcdServer) UserDelete(ctx context.Context, r *pb.AuthUserDeleteRequest) (*pb.AuthUserDeleteResponse, error) {
+	resp, err := s.raftRequest(ctx, pb.InternalRaftRequest{AuthUserDelete: r})
+	if err != nil {
+		return nil, err
+	}
+	return resp.(*pb.AuthUserDeleteResponse), nil
+}
+
+func (s *EtcdServer) UserChangePassword(ctx context.Context, r *pb.AuthUserChangePasswordRequest) (*pb.AuthUserChangePasswordResponse, error) {
+	if r.Password != "" {
+		hashedPassword, err := bcrypt.GenerateFromPassword([]byte(r.Password), s.authStore.BcryptCost())
+		if err != nil {
+			return nil, err
+		}
+		r.HashedPassword = base64.StdEncoding.EncodeToString(hashedPassword)
+		r.Password = ""
+	}
+
+	resp, err := s.raftRequest(ctx, pb.InternalRaftRequest{AuthUserChangePassword: r})
+	if err != nil {
+		return nil, err
+	}
+	return resp.(*pb.AuthUserChangePasswordResponse), nil
+}
+
+func (s *EtcdServer) UserGrantRole(ctx context.Context, r *pb.AuthUserGrantRoleRequest) (*pb.AuthUserGrantRoleResponse, error) {
+	resp, err := s.raftRequest(ctx, pb.InternalRaftRequest{AuthUserGrantRole: r})
+	if err != nil {
+		return nil, err
+	}
+	return resp.(*pb.AuthUserGrantRoleResponse), nil
+}
+
+func (s *EtcdServer) UserGet(ctx context.Context, r *pb.AuthUserGetRequest) (*pb.AuthUserGetResponse, error) {
+	resp, err := s.raftRequest(ctx, pb.InternalRaftRequest{AuthUserGet: r})
+	if err != nil {
+		return nil, err
+	}
+	return resp.(*pb.AuthUserGetResponse), nil
+}
+
+func (s *EtcdServer) UserList(ctx context.Context, r *pb.AuthUserListRequest) (*pb.AuthUserListResponse, error) {
+	resp, err := s.raftRequest(ctx, pb.InternalRaftRequest{AuthUserList: r})
+	if err != nil {
+		return nil, err
+	}
+	return resp.(*pb.AuthUserListResponse), nil
+}
+
+func (s *EtcdServer) UserRevokeRole(ctx context.Context, r *pb.AuthUserRevokeRoleRequest) (*pb.AuthUserRevokeRoleResponse, error) {
+	resp, err := s.raftRequest(ctx, pb.InternalRaftRequest{AuthUserRevokeRole: r})
+	if err != nil {
+		return nil, err
+	}
+	return resp.(*pb.AuthUserRevokeRoleResponse), nil
+}
+
+func (s *EtcdServer) RoleAdd(ctx context.Context, r *pb.AuthRoleAddRequest) (*pb.AuthRoleAddResponse, error) {
+	resp, err := s.raftRequest(ctx, pb.InternalRaftRequest{AuthRoleAdd: r})
+	if err != nil {
+		return nil, err
+	}
+	return resp.(*pb.AuthRoleAddResponse), nil
+}
+
+func (s *EtcdServer) RoleGrantPermission(ctx context.Context, r *pb.AuthRoleGrantPermissionRequest) (*pb.AuthRoleGrantPermissionResponse, error) {
+	resp, err := s.raftRequest(ctx, pb.InternalRaftRequest{AuthRoleGrantPermission: r})
+	if err != nil {
+		return nil, err
+	}
+	return resp.(*pb.AuthRoleGrantPermissionResponse), nil
+}
+
+func (s *EtcdServer) RoleGet(ctx context.Context, r *pb.AuthRoleGetRequest) (*pb.AuthRoleGetResponse, error) {
+	resp, err := s.raftRequest(ctx, pb.InternalRaftRequest{AuthRoleGet: r})
+	if err != nil {
+		return nil, err
+	}
+	return resp.(*pb.AuthRoleGetResponse), nil
+}
+
+func (s *EtcdServer) RoleList(ctx context.Context, r *pb.AuthRoleListRequest) (*pb.AuthRoleListResponse, error) {
+	resp, err := s.raftRequest(ctx, pb.InternalRaftRequest{AuthRoleList: r})
+	if err != nil {
+		return nil, err
+	}
+	return resp.(*pb.AuthRoleListResponse), nil
+}
+
+func (s *EtcdServer) RoleRevokePermission(ctx context.Context, r *pb.AuthRoleRevokePermissionRequest) (*pb.AuthRoleRevokePermissionResponse, error) {
+	resp, err := s.raftRequest(ctx, pb.InternalRaftRequest{AuthRoleRevokePermission: r})
+	if err != nil {
+		return nil, err
+	}
+	return resp.(*pb.AuthRoleRevokePermissionResponse), nil
+}
+
+func (s *EtcdServer) RoleDelete(ctx context.Context, r *pb.AuthRoleDeleteRequest) (*pb.AuthRoleDeleteResponse, error) {
+	resp, err := s.raftRequest(ctx, pb.InternalRaftRequest{AuthRoleDelete: r})
+	if err != nil {
+		return nil, err
+	}
+	return resp.(*pb.AuthRoleDeleteResponse), nil
+}
+
+func (s *EtcdServer) raftRequestOnce(ctx context.Context, r pb.InternalRaftRequest) (proto.Message, error) {
+	result, err := s.processInternalRaftRequestOnce(ctx, r)
+	if err != nil {
+		return nil, err
+	}
+	if result.Err != nil {
+		return nil, result.Err
+	}
+	if startTime, ok := ctx.Value(traceutil.StartTimeKey{}).(time.Time); ok && result.Trace != nil {
+		applyStart := result.Trace.GetStartTime()
+		// The trace object is created in toApply. Here reset the start time to trace
+		// the raft request time by the difference between the request start time
+		// and toApply start time
+		result.Trace.SetStartTime(startTime)
+		result.Trace.InsertStep(0, applyStart, "process raft request")
+		result.Trace.LogIfLong(traceThreshold)
+	}
+	return result.Resp, nil
+}
+
+func (s *EtcdServer) raftRequest(ctx context.Context, r pb.InternalRaftRequest) (proto.Message, error) {
+	return s.raftRequestOnce(ctx, r)
+}
+
+// doSerialize handles the auth logic, with permissions checked by "chk", for a serialized request "get". Returns a non-nil error on authentication failure.
+func (s *EtcdServer) doSerialize(ctx context.Context, chk func(*auth.AuthInfo) error, get func()) error {
+	trace := traceutil.Get(ctx)
+	ai, err := s.AuthInfoFromCtx(ctx)
+	if err != nil {
+		return err
+	}
+	if ai == nil {
+		// chk expects non-nil AuthInfo; use empty credentials
+		ai = &auth.AuthInfo{}
+	}
+	if err = chk(ai); err != nil {
+		return err
+	}
+	trace.Step("get authentication metadata")
+	// fetch response for serialized request
+	get()
+	// check for stale token revision in case the auth store was updated while
+	// the request has been handled.
+	if ai.Revision != 0 && ai.Revision != s.authStore.Revision() {
+		return auth.ErrAuthOldRevision
+	}
+	return nil
+}
+
+func (s *EtcdServer) processInternalRaftRequestOnce(ctx context.Context, r pb.InternalRaftRequest) (*apply2.Result, error) {
+	ai := s.getAppliedIndex()
+	ci := s.getCommittedIndex()
+	if ci > ai+maxGapBetweenApplyAndCommitIndex {
+		return nil, errors.ErrTooManyRequests
+	}
+
+	r.Header = &pb.RequestHeader{
+		ID: s.reqIDGen.Next(),
+	}
+
+	// check authinfo if it is not InternalAuthenticateRequest
+	if r.Authenticate == nil {
+		authInfo, err := s.AuthInfoFromCtx(ctx)
+		if err != nil {
+			return nil, err
+		}
+		if authInfo != nil {
+			r.Header.Username = authInfo.Username
+			r.Header.AuthRevision = authInfo.Revision
+		}
+	}
+
+	data, err := r.Marshal()
+	if err != nil {
+		return nil, err
+	}
+
+	if len(data) > int(s.Cfg.MaxRequestBytes) {
+		return nil, errors.ErrRequestTooLarge
+	}
+
+	id := r.ID
+	if id == 0 {
+		id = r.Header.ID
+	}
+	ch := s.w.Register(id)
+
+	cctx, cancel := context.WithTimeout(ctx, s.Cfg.ReqTimeout())
+	defer cancel()
+
+	start := time.Now()
+	err = s.r.Propose(cctx, data)
+	if err != nil {
+		proposalsFailed.Inc()
+		s.w.Trigger(id, nil) // GC wait
+		return nil, err
+	}
+	proposalsPending.Inc()
+	defer proposalsPending.Dec()
+
+	select {
+	case x := <-ch:
+		return x.(*apply2.Result), nil
+	case <-cctx.Done():
+		proposalsFailed.Inc()
+		s.w.Trigger(id, nil) // GC wait
+		return nil, s.parseProposeCtxErr(cctx.Err(), start)
+	case <-s.done:
+		return nil, errors.ErrStopped
+	}
+}
+
+// Watchable returns a watchable interface attached to the etcdserver.
+func (s *EtcdServer) Watchable() mvcc.WatchableKV { return s.KV() }
+
+func (s *EtcdServer) linearizableReadLoop() {
+	for {
+		requestID := s.reqIDGen.Next()
+		leaderChangedNotifier := s.leaderChanged.Receive()
+		select {
+		case <-leaderChangedNotifier:
+			continue
+		case <-s.readwaitc:
+		case <-s.stopping:
+			return
+		}
+
+		// as a single loop is can unlock multiple reads, it is not very useful
+		// to propagate the trace from Txn or Range.
+		trace := traceutil.New("linearizableReadLoop", s.Logger())
+
+		nextnr := newNotifier()
+		s.readMu.Lock()
+		nr := s.readNotifier
+		s.readNotifier = nextnr
+		s.readMu.Unlock()
+
+		confirmedIndex, err := s.requestCurrentIndex(leaderChangedNotifier, requestID)
+		if isStopped(err) {
+			return
+		}
+		if err != nil {
+			nr.notify(err)
+			continue
+		}
+
+		trace.Step("read index received")
+
+		trace.AddField(traceutil.Field{Key: "readStateIndex", Value: confirmedIndex})
+
+		appliedIndex := s.getAppliedIndex()
+		trace.AddField(traceutil.Field{Key: "appliedIndex", Value: strconv.FormatUint(appliedIndex, 10)})
+
+		if appliedIndex < confirmedIndex {
+			select {
+			case <-s.applyWait.Wait(confirmedIndex):
+			case <-s.stopping:
+				return
+			}
+		}
+		// unblock all l-reads requested at indices before confirmedIndex
+		nr.notify(nil)
+		trace.Step("applied index is now lower than readState.Index")
+
+		trace.LogAllStepsIfLong(traceThreshold)
+	}
+}
+
+func isStopped(err error) bool {
+	return errorspkg.Is(err, raft.ErrStopped) || errorspkg.Is(err, errors.ErrStopped)
+}
+
+func (s *EtcdServer) requestCurrentIndex(leaderChangedNotifier <-chan struct{}, requestID uint64) (uint64, error) {
+	err := s.sendReadIndex(requestID)
+	if err != nil {
+		return 0, err
+	}
+
+	lg := s.Logger()
+	errorTimer := time.NewTimer(s.Cfg.ReqTimeout())
+	defer errorTimer.Stop()
+	retryTimer := time.NewTimer(readIndexRetryTime)
+	defer retryTimer.Stop()
+
+	firstCommitInTermNotifier := s.firstCommitInTerm.Receive()
+
+	for {
+		select {
+		case rs := <-s.r.readStateC:
+			requestIDBytes := uint64ToBigEndianBytes(requestID)
+			gotOwnResponse := bytes.Equal(rs.RequestCtx, requestIDBytes)
+			if !gotOwnResponse {
+				// a previous request might time out. now we should ignore the response of it and
+				// continue waiting for the response of the current requests.
+				responseID := uint64(0)
+				if len(rs.RequestCtx) == 8 {
+					responseID = binary.BigEndian.Uint64(rs.RequestCtx)
+				}
+				lg.Warn(
+					"ignored out-of-date read index response; local node read indexes queueing up and waiting to be in sync with leader",
+					zap.Uint64("sent-request-id", requestID),
+					zap.Uint64("received-request-id", responseID),
+				)
+				slowReadIndex.Inc()
+				continue
+			}
+			return rs.Index, nil
+		case <-leaderChangedNotifier:
+			readIndexFailed.Inc()
+			// return a retryable error.
+			return 0, errors.ErrLeaderChanged
+		case <-firstCommitInTermNotifier:
+			firstCommitInTermNotifier = s.firstCommitInTerm.Receive()
+			lg.Info("first commit in current term: resending ReadIndex request")
+			err := s.sendReadIndex(requestID)
+			if err != nil {
+				return 0, err
+			}
+			retryTimer.Reset(readIndexRetryTime)
+			continue
+		case <-retryTimer.C:
+			lg.Warn(
+				"waiting for ReadIndex response took too long, retrying",
+				zap.Uint64("sent-request-id", requestID),
+				zap.Duration("retry-timeout", readIndexRetryTime),
+			)
+			err := s.sendReadIndex(requestID)
+			if err != nil {
+				return 0, err
+			}
+			retryTimer.Reset(readIndexRetryTime)
+			continue
+		case <-errorTimer.C:
+			lg.Warn(
+				"timed out waiting for read index response (local node might have slow network)",
+				zap.Duration("timeout", s.Cfg.ReqTimeout()),
+			)
+			slowReadIndex.Inc()
+			return 0, errors.ErrTimeout
+		case <-s.stopping:
+			return 0, errors.ErrStopped
+		}
+	}
+}
+
+func uint64ToBigEndianBytes(number uint64) []byte {
+	byteResult := make([]byte, 8)
+	binary.BigEndian.PutUint64(byteResult, number)
+	return byteResult
+}
+
+func (s *EtcdServer) sendReadIndex(requestIndex uint64) error {
+	ctxToSend := uint64ToBigEndianBytes(requestIndex)
+
+	cctx, cancel := context.WithTimeout(context.Background(), s.Cfg.ReqTimeout())
+	err := s.r.ReadIndex(cctx, ctxToSend)
+	cancel()
+	if errorspkg.Is(err, raft.ErrStopped) {
+		return err
+	}
+	if err != nil {
+		lg := s.Logger()
+		lg.Warn("failed to get read index from Raft", zap.Error(err))
+		readIndexFailed.Inc()
+		return err
+	}
+	return nil
+}
+
+func (s *EtcdServer) LinearizableReadNotify(ctx context.Context) error {
+	return s.linearizableReadNotify(ctx)
+}
+
+func (s *EtcdServer) linearizableReadNotify(ctx context.Context) error {
+	s.readMu.RLock()
+	nc := s.readNotifier
+	s.readMu.RUnlock()
+
+	// signal linearizable loop for current notify if it hasn't been already
+	select {
+	case s.readwaitc <- struct{}{}:
+	default:
+	}
+
+	// wait for read state notification
+	select {
+	case <-nc.c:
+		return nc.err
+	case <-ctx.Done():
+		return ctx.Err()
+	case <-s.done:
+		return errors.ErrStopped
+	}
+}
+
+func (s *EtcdServer) AuthInfoFromCtx(ctx context.Context) (*auth.AuthInfo, error) {
+	authInfo, err := s.AuthStore().AuthInfoFromCtx(ctx)
+	if authInfo != nil || err != nil {
+		return authInfo, err
+	}
+	if !s.Cfg.ClientCertAuthEnabled {
+		return nil, nil
+	}
+	authInfo = s.AuthStore().AuthInfoFromTLS(ctx)
+	return authInfo, nil
+}
+
+func (s *EtcdServer) Downgrade(ctx context.Context, r *pb.DowngradeRequest) (*pb.DowngradeResponse, error) {
+	switch r.Action {
+	case pb.DowngradeRequest_VALIDATE:
+		return s.downgradeValidate(ctx, r.Version)
+	case pb.DowngradeRequest_ENABLE:
+		return s.downgradeEnable(ctx, r)
+	case pb.DowngradeRequest_CANCEL:
+		return s.downgradeCancel(ctx)
+	default:
+		return nil, errors.ErrUnknownMethod
+	}
+}
+
+func (s *EtcdServer) downgradeValidate(ctx context.Context, v string) (*pb.DowngradeResponse, error) {
+	resp := &pb.DowngradeResponse{}
+
+	targetVersion, err := convertToClusterVersion(v)
+	if err != nil {
+		return nil, err
+	}
+
+	cv := s.ClusterVersion()
+	if cv == nil {
+		return nil, errors.ErrClusterVersionUnavailable
+	}
+	resp.Version = version.Cluster(cv.String())
+	err = s.Version().DowngradeValidate(ctx, targetVersion)
+	if err != nil {
+		return nil, err
+	}
+
+	return resp, nil
+}
+
+func (s *EtcdServer) downgradeEnable(ctx context.Context, r *pb.DowngradeRequest) (*pb.DowngradeResponse, error) {
+	lg := s.Logger()
+	targetVersion, err := convertToClusterVersion(r.Version)
+	if err != nil {
+		lg.Warn("reject downgrade request", zap.Error(err))
+		return nil, err
+	}
+	err = s.Version().DowngradeEnable(ctx, targetVersion)
+	if err != nil {
+		lg.Warn("reject downgrade request", zap.Error(err))
+		return nil, err
+	}
+	resp := pb.DowngradeResponse{Version: version.Cluster(s.ClusterVersion().String())}
+	return &resp, nil
+}
+
+func (s *EtcdServer) downgradeCancel(ctx context.Context) (*pb.DowngradeResponse, error) {
+	err := s.Version().DowngradeCancel(ctx)
+	if err != nil {
+		s.lg.Warn("failed to cancel downgrade", zap.Error(err))
+	}
+	resp := pb.DowngradeResponse{Version: version.Cluster(s.ClusterVersion().String())}
+	return &resp, nil
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/version/doc.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/version/doc.go
new file mode 100644
index 0000000..c34f905
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/version/doc.go
@@ -0,0 +1,16 @@
+// Copyright 2021 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package version provides functions for getting/saving storage version.
+package version
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/version/downgrade.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/version/downgrade.go
new file mode 100644
index 0000000..f2c6e11
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/version/downgrade.go
@@ -0,0 +1,76 @@
+// Copyright 2020 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package version
+
+import (
+	"github.com/coreos/go-semver/semver"
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/api/v3/version"
+)
+
+type DowngradeInfo struct {
+	// TargetVersion is the target downgrade version, if the cluster is not under downgrading,
+	// the targetVersion will be an empty string
+	TargetVersion string `json:"target-version"`
+	// Enabled indicates whether the cluster is enabled to downgrade
+	Enabled bool `json:"enabled"`
+}
+
+func (d *DowngradeInfo) GetTargetVersion() *semver.Version {
+	return semver.Must(semver.NewVersion(d.TargetVersion))
+}
+
+// isValidDowngrade verifies whether the cluster can be downgraded from verFrom to verTo
+func isValidDowngrade(verFrom *semver.Version, verTo *semver.Version) bool {
+	return verTo.Equal(*allowedDowngradeVersion(verFrom))
+}
+
+// MustDetectDowngrade will detect local server joining cluster that doesn't support it's version.
+func MustDetectDowngrade(lg *zap.Logger, sv, cv *semver.Version) {
+	// only keep major.minor version for comparison against cluster version
+	sv = &semver.Version{Major: sv.Major, Minor: sv.Minor}
+
+	// if the cluster disables downgrade, check local version against determined cluster version.
+	// the validation passes when local version is not less than cluster version
+	if cv != nil && sv.LessThan(*cv) {
+		lg.Panic(
+			"invalid downgrade; server version is lower than determined cluster version",
+			zap.String("current-server-version", sv.String()),
+			zap.String("determined-cluster-version", version.Cluster(cv.String())),
+		)
+	}
+}
+
+func allowedDowngradeVersion(ver *semver.Version) *semver.Version {
+	// Todo: handle the case that downgrading from higher major version(e.g. downgrade from v4.0 to v3.x)
+	return &semver.Version{Major: ver.Major, Minor: ver.Minor - 1}
+}
+
+// IsValidClusterVersionChange checks the two scenario when version is valid to change:
+// 1. Downgrade: cluster version is 1 minor version higher than local version,
+// cluster version should change.
+// 2. Cluster start: when not all members version are available, cluster version
+// is set to MinVersion(3.0), when all members are at higher version, cluster version
+// is lower than minimal server version, cluster version should change
+func IsValidClusterVersionChange(verFrom *semver.Version, verTo *semver.Version) bool {
+	verFrom = &semver.Version{Major: verFrom.Major, Minor: verFrom.Minor}
+	verTo = &semver.Version{Major: verTo.Major, Minor: verTo.Minor}
+
+	if isValidDowngrade(verFrom, verTo) || (verFrom.Major == verTo.Major && verFrom.LessThan(*verTo)) {
+		return true
+	}
+	return false
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/version/errors.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/version/errors.go
new file mode 100644
index 0000000..906aa9f
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/version/errors.go
@@ -0,0 +1,23 @@
+// Copyright 2021 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package version
+
+import "errors"
+
+var (
+	ErrInvalidDowngradeTargetVersion = errors.New("etcdserver: invalid downgrade target version")
+	ErrDowngradeInProcess            = errors.New("etcdserver: cluster has a downgrade job in progress")
+	ErrNoInflightDowngrade           = errors.New("etcdserver: no inflight downgrade job")
+)
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/version/monitor.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/version/monitor.go
new file mode 100644
index 0000000..b3e7f58
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/version/monitor.go
@@ -0,0 +1,221 @@
+// Copyright 2021 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package version
+
+import (
+	"context"
+	"errors"
+
+	"github.com/coreos/go-semver/semver"
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/api/v3/version"
+)
+
+// Monitor contains logic used by cluster leader to monitor version changes and decide on cluster version or downgrade progress.
+type Monitor struct {
+	lg *zap.Logger
+	s  Server
+}
+
+// Server lists EtcdServer methods needed by Monitor
+type Server interface {
+	GetClusterVersion() *semver.Version
+	GetDowngradeInfo() *DowngradeInfo
+	GetMembersVersions() map[string]*version.Versions
+	UpdateClusterVersion(string)
+	LinearizableReadNotify(ctx context.Context) error
+	DowngradeEnable(ctx context.Context, targetVersion *semver.Version) error
+	DowngradeCancel(ctx context.Context) error
+
+	GetStorageVersion() *semver.Version
+	UpdateStorageVersion(semver.Version) error
+}
+
+func NewMonitor(lg *zap.Logger, storage Server) *Monitor {
+	return &Monitor{
+		lg: lg,
+		s:  storage,
+	}
+}
+
+// UpdateClusterVersionIfNeeded updates the cluster version.
+func (m *Monitor) UpdateClusterVersionIfNeeded() error {
+	newClusterVersion, err := m.decideClusterVersion()
+	if newClusterVersion != nil {
+		newClusterVersion = &semver.Version{Major: newClusterVersion.Major, Minor: newClusterVersion.Minor}
+		m.s.UpdateClusterVersion(newClusterVersion.String())
+	}
+	return err
+}
+
+// decideClusterVersion decides whether to change cluster version and its next value.
+// New cluster version is based on the members versions server and whether cluster is downgrading.
+// Returns nil if cluster version should be left unchanged.
+func (m *Monitor) decideClusterVersion() (*semver.Version, error) {
+	clusterVersion := m.s.GetClusterVersion()
+	minimalServerVersion := m.membersMinimalServerVersion()
+	if clusterVersion == nil {
+		if minimalServerVersion != nil {
+			return minimalServerVersion, nil
+		}
+		return semver.New(version.MinClusterVersion), nil
+	}
+	if minimalServerVersion == nil {
+		return nil, nil
+	}
+	downgrade := m.s.GetDowngradeInfo()
+	if downgrade != nil && downgrade.Enabled {
+		if downgrade.GetTargetVersion().Equal(*clusterVersion) {
+			return nil, nil
+		}
+		if !isValidDowngrade(clusterVersion, downgrade.GetTargetVersion()) {
+			m.lg.Error("Cannot downgrade from cluster-version to downgrade-target",
+				zap.String("downgrade-target", downgrade.TargetVersion),
+				zap.String("cluster-version", clusterVersion.String()),
+			)
+			return nil, errors.New("invalid downgrade target")
+		}
+		if !isValidDowngrade(minimalServerVersion, downgrade.GetTargetVersion()) {
+			m.lg.Error("Cannot downgrade from minimal-server-version to downgrade-target",
+				zap.String("downgrade-target", downgrade.TargetVersion),
+				zap.String("minimal-server-version", minimalServerVersion.String()),
+			)
+			return nil, errors.New("invalid downgrade target")
+		}
+		return downgrade.GetTargetVersion(), nil
+	}
+	if clusterVersion.LessThan(*minimalServerVersion) && IsValidClusterVersionChange(clusterVersion, minimalServerVersion) {
+		return minimalServerVersion, nil
+	}
+	return nil, nil
+}
+
+// UpdateStorageVersionIfNeeded updates the storage version if it differs from cluster version.
+func (m *Monitor) UpdateStorageVersionIfNeeded() {
+	cv := m.s.GetClusterVersion()
+	if cv == nil || cv.String() == version.MinClusterVersion {
+		return
+	}
+	sv := m.s.GetStorageVersion()
+
+	if sv == nil || sv.Major != cv.Major || sv.Minor != cv.Minor {
+		if sv != nil {
+			m.lg.Info("cluster version differs from storage version.", zap.String("cluster-version", cv.String()), zap.String("storage-version", sv.String()))
+		}
+		err := m.s.UpdateStorageVersion(semver.Version{Major: cv.Major, Minor: cv.Minor})
+		if err != nil {
+			m.lg.Error("failed to update storage version", zap.String("cluster-version", cv.String()), zap.Error(err))
+			return
+		}
+		d := m.s.GetDowngradeInfo()
+		if d != nil && d.Enabled {
+			m.lg.Info(
+				"The server is ready to downgrade",
+				zap.String("target-version", d.TargetVersion),
+				zap.String("server-version", version.Version),
+			)
+		}
+	}
+}
+
+func (m *Monitor) CancelDowngradeIfNeeded() {
+	d := m.s.GetDowngradeInfo()
+	if d == nil || !d.Enabled {
+		return
+	}
+
+	targetVersion := d.TargetVersion
+	v := semver.Must(semver.NewVersion(targetVersion))
+	if m.versionsMatchTarget(v) {
+		m.lg.Info("the cluster has been downgraded", zap.String("cluster-version", targetVersion))
+		err := m.s.DowngradeCancel(context.Background())
+		if err != nil {
+			m.lg.Warn("failed to cancel downgrade", zap.Error(err))
+		}
+	}
+}
+
+// membersMinimalServerVersion returns the min server version in the map, or nil if the min
+// version in unknown.
+// It prints out log if there is a member with a higher version than the
+// local version.
+func (m *Monitor) membersMinimalServerVersion() *semver.Version {
+	vers := m.s.GetMembersVersions()
+	var minV *semver.Version
+	lv := semver.Must(semver.NewVersion(version.Version))
+
+	for mid, ver := range vers {
+		if ver == nil {
+			return nil
+		}
+		v, err := semver.NewVersion(ver.Server)
+		if err != nil {
+			m.lg.Warn(
+				"failed to parse server version of remote member",
+				zap.String("remote-member-id", mid),
+				zap.String("remote-member-version", ver.Server),
+				zap.Error(err),
+			)
+			return nil
+		}
+		if lv.LessThan(*v) {
+			m.lg.Warn(
+				"leader found higher-versioned member",
+				zap.String("local-member-version", lv.String()),
+				zap.String("remote-member-id", mid),
+				zap.String("remote-member-version", ver.Server),
+			)
+		}
+		if minV == nil {
+			minV = v
+		} else if v.LessThan(*minV) {
+			minV = v
+		}
+	}
+	return minV
+}
+
+// versionsMatchTarget returns true if all server versions are equal to target version, otherwise return false.
+// It can be used to decide the whether the cluster finishes downgrading to target version.
+func (m *Monitor) versionsMatchTarget(targetVersion *semver.Version) bool {
+	vers := m.s.GetMembersVersions()
+	targetVersion = &semver.Version{Major: targetVersion.Major, Minor: targetVersion.Minor}
+	for mid, ver := range vers {
+		if ver == nil {
+			return false
+		}
+		v, err := semver.NewVersion(ver.Server)
+		if err != nil {
+			m.lg.Warn(
+				"failed to parse server version of remote member",
+				zap.String("remote-member-id", mid),
+				zap.String("remote-member-version", ver.Server),
+				zap.Error(err),
+			)
+			return false
+		}
+		v = &semver.Version{Major: v.Major, Minor: v.Minor}
+		if !targetVersion.Equal(*v) {
+			m.lg.Warn("remotes server has mismatching etcd version",
+				zap.String("remote-member-id", mid),
+				zap.String("current-server-version", v.String()),
+				zap.String("target-version", targetVersion.String()),
+			)
+			return false
+		}
+	}
+	return true
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/version/version.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/version/version.go
new file mode 100644
index 0000000..0a2f99a
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/version/version.go
@@ -0,0 +1,81 @@
+// Copyright 2021 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package version
+
+import (
+	"context"
+
+	"github.com/coreos/go-semver/semver"
+	"go.uber.org/zap"
+)
+
+// Manager contains logic to manage etcd cluster version downgrade process.
+type Manager struct {
+	lg *zap.Logger
+	s  Server
+}
+
+// NewManager returns a new manager instance
+func NewManager(lg *zap.Logger, s Server) *Manager {
+	return &Manager{
+		lg: lg,
+		s:  s,
+	}
+}
+
+// DowngradeValidate validates if cluster is downloadable to provided target version and returns error if not.
+func (m *Manager) DowngradeValidate(ctx context.Context, targetVersion *semver.Version) error {
+	// gets leaders commit index and wait for local store to finish applying that index
+	// to avoid using stale downgrade information
+	err := m.s.LinearizableReadNotify(ctx)
+	if err != nil {
+		return err
+	}
+	cv := m.s.GetClusterVersion()
+	allowedTargetVersion := allowedDowngradeVersion(cv)
+	if !targetVersion.Equal(*allowedTargetVersion) {
+		return ErrInvalidDowngradeTargetVersion
+	}
+
+	downgradeInfo := m.s.GetDowngradeInfo()
+	if downgradeInfo != nil && downgradeInfo.Enabled {
+		// Todo: return the downgrade status along with the error msg
+		return ErrDowngradeInProcess
+	}
+	return nil
+}
+
+// DowngradeEnable initiates etcd cluster version downgrade process.
+func (m *Manager) DowngradeEnable(ctx context.Context, targetVersion *semver.Version) error {
+	// validate downgrade capability before starting downgrade
+	err := m.DowngradeValidate(ctx, targetVersion)
+	if err != nil {
+		return err
+	}
+	return m.s.DowngradeEnable(ctx, targetVersion)
+}
+
+// DowngradeCancel cancels ongoing downgrade process.
+func (m *Manager) DowngradeCancel(ctx context.Context) error {
+	err := m.s.LinearizableReadNotify(ctx)
+	if err != nil {
+		return err
+	}
+	downgradeInfo := m.s.GetDowngradeInfo()
+	if !downgradeInfo.Enabled {
+		return ErrNoInflightDowngrade
+	}
+	return m.s.DowngradeCancel(ctx)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/etcdserver/zap_raft.go b/vendor/go.etcd.io/etcd/server/v3/etcdserver/zap_raft.go
new file mode 100644
index 0000000..7672bdf
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/etcdserver/zap_raft.go
@@ -0,0 +1,103 @@
+// Copyright 2018 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package etcdserver
+
+import (
+	"errors"
+
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
+
+	"go.etcd.io/raft/v3"
+)
+
+// NewRaftLogger builds "raft.Logger" from "*zap.Config".
+func NewRaftLogger(lcfg *zap.Config) (raft.Logger, error) {
+	if lcfg == nil {
+		return nil, errors.New("nil zap.Config")
+	}
+	lg, err := lcfg.Build(zap.AddCallerSkip(1)) // to annotate caller outside of "logutil"
+	if err != nil {
+		return nil, err
+	}
+	return &zapRaftLogger{lg: lg, sugar: lg.Sugar()}, nil
+}
+
+// NewRaftLoggerZap converts "*zap.Logger" to "raft.Logger".
+func NewRaftLoggerZap(lg *zap.Logger) raft.Logger {
+	skipCallerLg := lg.WithOptions(zap.AddCallerSkip(1))
+	return &zapRaftLogger{lg: skipCallerLg, sugar: skipCallerLg.Sugar()}
+}
+
+// NewRaftLoggerFromZapCore creates "raft.Logger" from "zap.Core"
+// and "zapcore.WriteSyncer".
+func NewRaftLoggerFromZapCore(cr zapcore.Core, syncer zapcore.WriteSyncer) raft.Logger {
+	// "AddCallerSkip" to annotate caller outside of "logutil"
+	lg := zap.New(cr, zap.AddCaller(), zap.AddCallerSkip(1), zap.ErrorOutput(syncer))
+	return &zapRaftLogger{lg: lg, sugar: lg.Sugar()}
+}
+
+type zapRaftLogger struct {
+	lg    *zap.Logger
+	sugar *zap.SugaredLogger
+}
+
+func (zl *zapRaftLogger) Debug(args ...any) {
+	zl.sugar.Debug(args...)
+}
+
+func (zl *zapRaftLogger) Debugf(format string, args ...any) {
+	zl.sugar.Debugf(format, args...)
+}
+
+func (zl *zapRaftLogger) Error(args ...any) {
+	zl.sugar.Error(args...)
+}
+
+func (zl *zapRaftLogger) Errorf(format string, args ...any) {
+	zl.sugar.Errorf(format, args...)
+}
+
+func (zl *zapRaftLogger) Info(args ...any) {
+	zl.sugar.Info(args...)
+}
+
+func (zl *zapRaftLogger) Infof(format string, args ...any) {
+	zl.sugar.Infof(format, args...)
+}
+
+func (zl *zapRaftLogger) Warning(args ...any) {
+	zl.sugar.Warn(args...)
+}
+
+func (zl *zapRaftLogger) Warningf(format string, args ...any) {
+	zl.sugar.Warnf(format, args...)
+}
+
+func (zl *zapRaftLogger) Fatal(args ...any) {
+	zl.sugar.Fatal(args...)
+}
+
+func (zl *zapRaftLogger) Fatalf(format string, args ...any) {
+	zl.sugar.Fatalf(format, args...)
+}
+
+func (zl *zapRaftLogger) Panic(args ...any) {
+	zl.sugar.Panic(args...)
+}
+
+func (zl *zapRaftLogger) Panicf(format string, args ...any) {
+	zl.sugar.Panicf(format, args...)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/features/etcd_features.go b/vendor/go.etcd.io/etcd/server/v3/features/etcd_features.go
new file mode 100644
index 0000000..230b37c
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/features/etcd_features.go
@@ -0,0 +1,108 @@
+// Copyright 2024 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package features
+
+import (
+	"fmt"
+
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/pkg/v3/featuregate"
+)
+
+const (
+	// Every feature gate should add method here following this template:
+	//
+	// // owner: @username
+	// // kep: https://kep.k8s.io/NNN (or issue: https://github.com/etcd-io/etcd/issues/NNN, or main PR: https://github.com/etcd-io/etcd/pull/NNN)
+	// // alpha: v3.X
+	// MyFeature featuregate.Feature = "MyFeature"
+	//
+	// Feature gates should be listed in alphabetical, case-sensitive
+	// (upper before any lower case character) order. This reduces the risk
+	// of code conflicts because changes are more likely to be scattered
+	// across the file.
+
+	// StopGRPCServiceOnDefrag enables etcd gRPC service to stop serving client requests on defragmentation.
+	// owner: @chaochn47
+	// alpha: v3.6
+	// main PR: https://github.com/etcd-io/etcd/pull/18279
+	StopGRPCServiceOnDefrag featuregate.Feature = "StopGRPCServiceOnDefrag"
+	// TxnModeWriteWithSharedBuffer enables the write transaction to use a shared buffer in its readonly check operations.
+	// owner: @wilsonwang371
+	// beta: v3.5
+	// main PR: https://github.com/etcd-io/etcd/pull/12896
+	TxnModeWriteWithSharedBuffer featuregate.Feature = "TxnModeWriteWithSharedBuffer"
+	// InitialCorruptCheck enable to check data corruption before serving any client/peer traffic.
+	// owner: @serathius
+	// alpha: v3.6
+	// main PR: https://github.com/etcd-io/etcd/pull/10524
+	InitialCorruptCheck featuregate.Feature = "InitialCorruptCheck"
+	// CompactHashCheck enables leader to periodically check followers compaction hashes.
+	// owner: @serathius
+	// alpha: v3.6
+	// main PR: https://github.com/etcd-io/etcd/pull/14120
+	CompactHashCheck featuregate.Feature = "CompactHashCheck"
+	// LeaseCheckpoint enables leader to send regular checkpoints to other members to prevent reset of remaining TTL on leader change.
+	// owner: @serathius
+	// alpha: v3.6
+	// main PR: https://github.com/etcd-io/etcd/pull/13508
+	LeaseCheckpoint featuregate.Feature = "LeaseCheckpoint"
+	// LeaseCheckpointPersist enables persisting remainingTTL to prevent indefinite auto-renewal of long lived leases. Always enabled in v3.6. Should be used to ensure smooth upgrade from v3.5 clusters with this feature enabled.
+	// Requires EnableLeaseCheckpoint featuragate to be enabled.
+	// TODO: Delete in v3.7
+	// owner: @serathius
+	// alpha: v3.6
+	// main PR: https://github.com/etcd-io/etcd/pull/13508
+	// Deprecated: Enabled by default in v3.6, to be removed in v3.7.
+	LeaseCheckpointPersist featuregate.Feature = "LeaseCheckpointPersist"
+	// SetMemberLocalAddr enables using the first specified and non-loopback local address from initial-advertise-peer-urls as the local address when communicating with a peer.
+	// Requires SetMemberLocalAddr featuragate to be enabled.
+	// owner: @flawedmatrix
+	// alpha: v3.6
+	// main PR: https://github.com/etcd-io/etcd/pull/17661
+	SetMemberLocalAddr featuregate.Feature = "SetMemberLocalAddr"
+)
+
+var (
+	DefaultEtcdServerFeatureGates = map[featuregate.Feature]featuregate.FeatureSpec{
+		StopGRPCServiceOnDefrag:      {Default: false, PreRelease: featuregate.Alpha},
+		InitialCorruptCheck:          {Default: false, PreRelease: featuregate.Alpha},
+		CompactHashCheck:             {Default: false, PreRelease: featuregate.Alpha},
+		TxnModeWriteWithSharedBuffer: {Default: true, PreRelease: featuregate.Beta},
+		LeaseCheckpoint:              {Default: false, PreRelease: featuregate.Alpha},
+		LeaseCheckpointPersist:       {Default: false, PreRelease: featuregate.Alpha},
+		SetMemberLocalAddr:           {Default: false, PreRelease: featuregate.Alpha},
+	}
+	// ExperimentalFlagToFeatureMap is the map from the cmd line flags of experimental features
+	// to their corresponding feature gates.
+	// Deprecated: Only add existing experimental features here. DO NOT use for new features.
+	ExperimentalFlagToFeatureMap = map[string]featuregate.Feature{
+		"experimental-stop-grpc-service-on-defrag":       StopGRPCServiceOnDefrag,
+		"experimental-initial-corrupt-check":             InitialCorruptCheck,
+		"experimental-compact-hash-check-enabled":        CompactHashCheck,
+		"experimental-txn-mode-write-with-shared-buffer": TxnModeWriteWithSharedBuffer,
+		"experimental-enable-lease-checkpoint":           LeaseCheckpoint,
+		"experimental-enable-lease-checkpoint-persist":   LeaseCheckpointPersist,
+	}
+)
+
+func NewDefaultServerFeatureGate(name string, lg *zap.Logger) featuregate.FeatureGate {
+	fg := featuregate.New(fmt.Sprintf("%sServerFeatureGate", name), lg)
+	if err := fg.Add(DefaultEtcdServerFeatureGates); err != nil {
+		panic(err)
+	}
+	return fg
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/README.md b/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/README.md
new file mode 100644
index 0000000..ff070c7
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/README.md
@@ -0,0 +1,113 @@
+# etcd/client
+
+etcd/client is the Go client library for etcd.
+
+[![GoDoc](https://godoc.org/go.etcd.io/etcd/client?status.png)](https://godoc.org/go.etcd.io/etcd/client)
+
+For full compatibility, it is recommended to install released versions of clients using go modules.
+
+## Install
+
+```bash
+go get go.etcd.io/etcd/v3/client
+```
+
+## Usage
+
+```go
+package main
+
+import (
+    "context"
+    "log"
+    "time"
+    
+    "go.etcd.io/etcd/v3/client"
+)
+
+func main() {
+	cfg := client.Config{
+		Endpoints:               []string{"http://127.0.0.1:2379"},
+		Transport:               client.DefaultTransport,
+		// set timeout per request to fail fast when the target endpoint is unavailable
+		HeaderTimeoutPerRequest: time.Second,
+	}
+	c, err := client.New(cfg)
+	if err != nil {
+		log.Fatal(err)
+	}
+	kapi := client.NewKeysAPI(c)
+	// set "/foo" key with "bar" value
+	log.Print("Setting '/foo' key with 'bar' value")
+	resp, err := kapi.Set(context.Background(), "/foo", "bar", nil)
+	if err != nil {
+		log.Fatal(err)
+	} else {
+		// print common key info
+		log.Printf("Set is done. Metadata is %q\n", resp)
+	}
+	// get "/foo" key's value
+	log.Print("Getting '/foo' key value")
+	resp, err = kapi.Get(context.Background(), "/foo", nil)
+	if err != nil {
+		log.Fatal(err)
+	} else {
+		// print common key info
+		log.Printf("Get is done. Metadata is %q\n", resp)
+		// print value
+		log.Printf("%q key has %q value\n", resp.Node.Key, resp.Node.Value)
+	}
+}
+```
+
+## Error Handling
+
+etcd client might return three types of errors.
+
+- context error
+
+Each API call has its first parameter as `context`. A context can be canceled or have an attached deadline. If the context is canceled or reaches its deadline, the responding context error will be returned no matter what internal errors the API call has already encountered.
+
+- cluster error
+
+Each API call tries to send request to the cluster endpoints one by one until it successfully gets a response. If a requests to an endpoint fails, due to exceeding per request timeout or connection issues, the error will be added into a list of errors. If all possible endpoints fail, a cluster error that includes all encountered errors will be returned.
+
+- response error
+
+If the response gets from the cluster is invalid, a plain string error will be returned. For example, it might be a invalid JSON error.
+
+Here is the example code to handle client errors:
+
+```go
+cfg := client.Config{Endpoints: []string{"http://etcd1:2379","http://etcd2:2379","http://etcd3:2379"}}
+c, err := client.New(cfg)
+if err != nil {
+	log.Fatal(err)
+}
+
+kapi := client.NewKeysAPI(c)
+resp, err := kapi.Set(ctx, "test", "bar", nil)
+if err != nil {
+	var cerr *client.ClusterError
+	if errors.Is(err, context.Canceled) {
+		// ctx is canceled by another routine
+	} else if errors.Is(err, context.DeadlineExceeded) {
+		// ctx is attached with a deadline and it exceeded
+	} else if errors.As(err, &cerr) {
+		// process (cerr.Errors)
+	} else {
+		// bad cluster endpoints, which are not etcd servers
+	}
+}
+```
+
+
+## Caveat
+
+1. etcd/client prefers to use the same endpoint as long as the endpoint continues to work well. This saves socket resources, and improves efficiency for both client and server side. This preference doesn't remove consistency from the data consumed by the client because data replicated to each etcd member has already passed through the consensus process.
+
+2. etcd/client does round-robin rotation on other available endpoints if the preferred endpoint isn't functioning properly. For example, if the member that etcd/client connects to is hard killed, etcd/client will fail on the first attempt with the killed member, and succeed on the second attempt with another member. If it fails to talk to all available endpoints, it will return all errors happened.
+
+3. Default etcd/client cannot handle the case that the remote server is SIGSTOPed now. TCP keepalive mechanism doesn't help in this scenario because operating system may still send TCP keep-alive packets. Over time we'd like to improve this functionality, but solving this issue isn't high priority because a real-life case in which a server is stopped, but the connection is kept alive, hasn't been brought to our attention.
+
+4. etcd/client cannot detect whether a member is healthy with watches and non-quorum read requests. If the member is isolated from the cluster, etcd/client may retrieve outdated data. Instead, users can either issue quorum read requests or monitor the /health endpoint for member health information.
diff --git a/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/auth_role.go b/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/auth_role.go
new file mode 100644
index 0000000..b9ef1aa
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/auth_role.go
@@ -0,0 +1,236 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package client
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/url"
+)
+
+type Role struct {
+	Role        string       `json:"role"`
+	Permissions Permissions  `json:"permissions"`
+	Grant       *Permissions `json:"grant,omitempty"`
+	Revoke      *Permissions `json:"revoke,omitempty"`
+}
+
+type Permissions struct {
+	KV rwPermission `json:"kv"`
+}
+
+type rwPermission struct {
+	Read  []string `json:"read"`
+	Write []string `json:"write"`
+}
+
+type PermissionType int
+
+const (
+	ReadPermission PermissionType = iota
+	WritePermission
+	ReadWritePermission
+)
+
+// NewAuthRoleAPI constructs a new AuthRoleAPI that uses HTTP to
+// interact with etcd's role creation and modification features.
+func NewAuthRoleAPI(c Client) AuthRoleAPI {
+	return &httpAuthRoleAPI{
+		client: c,
+	}
+}
+
+type AuthRoleAPI interface {
+	// AddRole adds a role.
+	AddRole(ctx context.Context, role string) error
+
+	// RemoveRole removes a role.
+	RemoveRole(ctx context.Context, role string) error
+
+	// GetRole retrieves role details.
+	GetRole(ctx context.Context, role string) (*Role, error)
+
+	// GrantRoleKV grants a role some permission prefixes for the KV store.
+	GrantRoleKV(ctx context.Context, role string, prefixes []string, permType PermissionType) (*Role, error)
+
+	// RevokeRoleKV revokes some permission prefixes for a role on the KV store.
+	RevokeRoleKV(ctx context.Context, role string, prefixes []string, permType PermissionType) (*Role, error)
+
+	// ListRoles lists roles.
+	ListRoles(ctx context.Context) ([]string, error)
+}
+
+type httpAuthRoleAPI struct {
+	client httpClient
+}
+
+type authRoleAPIAction struct {
+	verb string
+	name string
+	role *Role
+}
+
+type authRoleAPIList struct{}
+
+func (list *authRoleAPIList) HTTPRequest(ep url.URL) *http.Request {
+	u := v2AuthURL(ep, "roles", "")
+	req, _ := http.NewRequest(http.MethodGet, u.String(), nil)
+	req.Header.Set("Content-Type", "application/json")
+	return req
+}
+
+func (l *authRoleAPIAction) HTTPRequest(ep url.URL) *http.Request {
+	u := v2AuthURL(ep, "roles", l.name)
+	if l.role == nil {
+		req, _ := http.NewRequest(l.verb, u.String(), nil)
+		return req
+	}
+	b, err := json.Marshal(l.role)
+	if err != nil {
+		panic(err)
+	}
+	body := bytes.NewReader(b)
+	req, _ := http.NewRequest(l.verb, u.String(), body)
+	req.Header.Set("Content-Type", "application/json")
+	return req
+}
+
+func (r *httpAuthRoleAPI) ListRoles(ctx context.Context) ([]string, error) {
+	resp, body, err := r.client.Do(ctx, &authRoleAPIList{})
+	if err != nil {
+		return nil, err
+	}
+	if err = assertStatusCode(resp.StatusCode, http.StatusOK); err != nil {
+		return nil, err
+	}
+	var roleList struct {
+		Roles []Role `json:"roles"`
+	}
+	if err = json.Unmarshal(body, &roleList); err != nil {
+		return nil, err
+	}
+	ret := make([]string, 0, len(roleList.Roles))
+	for _, r := range roleList.Roles {
+		ret = append(ret, r.Role)
+	}
+	return ret, nil
+}
+
+func (r *httpAuthRoleAPI) AddRole(ctx context.Context, rolename string) error {
+	role := &Role{
+		Role: rolename,
+	}
+	return r.addRemoveRole(ctx, &authRoleAPIAction{
+		verb: http.MethodPut,
+		name: rolename,
+		role: role,
+	})
+}
+
+func (r *httpAuthRoleAPI) RemoveRole(ctx context.Context, rolename string) error {
+	return r.addRemoveRole(ctx, &authRoleAPIAction{
+		verb: http.MethodDelete,
+		name: rolename,
+	})
+}
+
+func (r *httpAuthRoleAPI) addRemoveRole(ctx context.Context, req *authRoleAPIAction) error {
+	resp, body, err := r.client.Do(ctx, req)
+	if err != nil {
+		return err
+	}
+	if err := assertStatusCode(resp.StatusCode, http.StatusOK, http.StatusCreated); err != nil {
+		var sec authError
+		err := json.Unmarshal(body, &sec)
+		if err != nil {
+			return err
+		}
+		return sec
+	}
+	return nil
+}
+
+func (r *httpAuthRoleAPI) GetRole(ctx context.Context, rolename string) (*Role, error) {
+	return r.modRole(ctx, &authRoleAPIAction{
+		verb: http.MethodGet,
+		name: rolename,
+	})
+}
+
+func buildRWPermission(prefixes []string, permType PermissionType) rwPermission {
+	var out rwPermission
+	switch permType {
+	case ReadPermission:
+		out.Read = prefixes
+	case WritePermission:
+		out.Write = prefixes
+	case ReadWritePermission:
+		out.Read = prefixes
+		out.Write = prefixes
+	}
+	return out
+}
+
+func (r *httpAuthRoleAPI) GrantRoleKV(ctx context.Context, rolename string, prefixes []string, permType PermissionType) (*Role, error) {
+	rwp := buildRWPermission(prefixes, permType)
+	role := &Role{
+		Role: rolename,
+		Grant: &Permissions{
+			KV: rwp,
+		},
+	}
+	return r.modRole(ctx, &authRoleAPIAction{
+		verb: http.MethodPut,
+		name: rolename,
+		role: role,
+	})
+}
+
+func (r *httpAuthRoleAPI) RevokeRoleKV(ctx context.Context, rolename string, prefixes []string, permType PermissionType) (*Role, error) {
+	rwp := buildRWPermission(prefixes, permType)
+	role := &Role{
+		Role: rolename,
+		Revoke: &Permissions{
+			KV: rwp,
+		},
+	}
+	return r.modRole(ctx, &authRoleAPIAction{
+		verb: http.MethodPut,
+		name: rolename,
+		role: role,
+	})
+}
+
+func (r *httpAuthRoleAPI) modRole(ctx context.Context, req *authRoleAPIAction) (*Role, error) {
+	resp, body, err := r.client.Do(ctx, req)
+	if err != nil {
+		return nil, err
+	}
+	if err = assertStatusCode(resp.StatusCode, http.StatusOK); err != nil {
+		var sec authError
+		err = json.Unmarshal(body, &sec)
+		if err != nil {
+			return nil, err
+		}
+		return nil, sec
+	}
+	var role Role
+	if err = json.Unmarshal(body, &role); err != nil {
+		return nil, err
+	}
+	return &role, nil
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/auth_user.go b/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/auth_user.go
new file mode 100644
index 0000000..75b636c
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/auth_user.go
@@ -0,0 +1,317 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package client
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/url"
+	"path"
+)
+
+var defaultV2AuthPrefix = "/v2/auth"
+
+type User struct {
+	User     string   `json:"user"`
+	Password string   `json:"password,omitempty"`
+	Roles    []string `json:"roles"`
+	Grant    []string `json:"grant,omitempty"`
+	Revoke   []string `json:"revoke,omitempty"`
+}
+
+// userListEntry is the user representation given by the server for ListUsers
+type userListEntry struct {
+	User  string `json:"user"`
+	Roles []Role `json:"roles"`
+}
+
+type UserRoles struct {
+	User  string `json:"user"`
+	Roles []Role `json:"roles"`
+}
+
+func v2AuthURL(ep url.URL, action string, name string) *url.URL {
+	if name != "" {
+		ep.Path = path.Join(ep.Path, defaultV2AuthPrefix, action, name)
+		return &ep
+	}
+	ep.Path = path.Join(ep.Path, defaultV2AuthPrefix, action)
+	return &ep
+}
+
+// NewAuthAPI constructs a new AuthAPI that uses HTTP to
+// interact with etcd's general auth features.
+func NewAuthAPI(c Client) AuthAPI {
+	return &httpAuthAPI{
+		client: c,
+	}
+}
+
+type AuthAPI interface {
+	// Enable auth.
+	Enable(ctx context.Context) error
+
+	// Disable auth.
+	Disable(ctx context.Context) error
+}
+
+type httpAuthAPI struct {
+	client httpClient
+}
+
+func (s *httpAuthAPI) Enable(ctx context.Context) error {
+	return s.enableDisable(ctx, &authAPIAction{http.MethodPut})
+}
+
+func (s *httpAuthAPI) Disable(ctx context.Context) error {
+	return s.enableDisable(ctx, &authAPIAction{http.MethodDelete})
+}
+
+func (s *httpAuthAPI) enableDisable(ctx context.Context, req httpAction) error {
+	resp, body, err := s.client.Do(ctx, req)
+	if err != nil {
+		return err
+	}
+	if err = assertStatusCode(resp.StatusCode, http.StatusOK, http.StatusCreated); err != nil {
+		var sec authError
+		err = json.Unmarshal(body, &sec)
+		if err != nil {
+			return err
+		}
+		return sec
+	}
+	return nil
+}
+
+type authAPIAction struct {
+	verb string
+}
+
+func (l *authAPIAction) HTTPRequest(ep url.URL) *http.Request {
+	u := v2AuthURL(ep, "enable", "")
+	req, _ := http.NewRequest(l.verb, u.String(), nil)
+	return req
+}
+
+type authError struct {
+	Message string `json:"message"`
+	Code    int    `json:"-"`
+}
+
+func (e authError) Error() string {
+	return e.Message
+}
+
+// NewAuthUserAPI constructs a new AuthUserAPI that uses HTTP to
+// interact with etcd's user creation and modification features.
+func NewAuthUserAPI(c Client) AuthUserAPI {
+	return &httpAuthUserAPI{
+		client: c,
+	}
+}
+
+type AuthUserAPI interface {
+	// AddUser adds a user.
+	AddUser(ctx context.Context, username string, password string) error
+
+	// RemoveUser removes a user.
+	RemoveUser(ctx context.Context, username string) error
+
+	// GetUser retrieves user details.
+	GetUser(ctx context.Context, username string) (*User, error)
+
+	// GrantUser grants a user some permission roles.
+	GrantUser(ctx context.Context, username string, roles []string) (*User, error)
+
+	// RevokeUser revokes some permission roles from a user.
+	RevokeUser(ctx context.Context, username string, roles []string) (*User, error)
+
+	// ChangePassword changes the user's password.
+	ChangePassword(ctx context.Context, username string, password string) (*User, error)
+
+	// ListUsers lists the users.
+	ListUsers(ctx context.Context) ([]string, error)
+}
+
+type httpAuthUserAPI struct {
+	client httpClient
+}
+
+type authUserAPIAction struct {
+	verb     string
+	username string
+	user     *User
+}
+
+type authUserAPIList struct{}
+
+func (list *authUserAPIList) HTTPRequest(ep url.URL) *http.Request {
+	u := v2AuthURL(ep, "users", "")
+	req, _ := http.NewRequest(http.MethodGet, u.String(), nil)
+	req.Header.Set("Content-Type", "application/json")
+	return req
+}
+
+func (l *authUserAPIAction) HTTPRequest(ep url.URL) *http.Request {
+	u := v2AuthURL(ep, "users", l.username)
+	if l.user == nil {
+		req, _ := http.NewRequest(l.verb, u.String(), nil)
+		return req
+	}
+	b, err := json.Marshal(l.user)
+	if err != nil {
+		panic(err)
+	}
+	body := bytes.NewReader(b)
+	req, _ := http.NewRequest(l.verb, u.String(), body)
+	req.Header.Set("Content-Type", "application/json")
+	return req
+}
+
+func (u *httpAuthUserAPI) ListUsers(ctx context.Context) ([]string, error) {
+	resp, body, err := u.client.Do(ctx, &authUserAPIList{})
+	if err != nil {
+		return nil, err
+	}
+	if err = assertStatusCode(resp.StatusCode, http.StatusOK); err != nil {
+		var sec authError
+		err = json.Unmarshal(body, &sec)
+		if err != nil {
+			return nil, err
+		}
+		return nil, sec
+	}
+
+	var userList struct {
+		Users []userListEntry `json:"users"`
+	}
+
+	if err = json.Unmarshal(body, &userList); err != nil {
+		return nil, err
+	}
+
+	ret := make([]string, 0, len(userList.Users))
+	for _, u := range userList.Users {
+		ret = append(ret, u.User)
+	}
+	return ret, nil
+}
+
+func (u *httpAuthUserAPI) AddUser(ctx context.Context, username string, password string) error {
+	user := &User{
+		User:     username,
+		Password: password,
+	}
+	return u.addRemoveUser(ctx, &authUserAPIAction{
+		verb:     http.MethodPut,
+		username: username,
+		user:     user,
+	})
+}
+
+func (u *httpAuthUserAPI) RemoveUser(ctx context.Context, username string) error {
+	return u.addRemoveUser(ctx, &authUserAPIAction{
+		verb:     http.MethodDelete,
+		username: username,
+	})
+}
+
+func (u *httpAuthUserAPI) addRemoveUser(ctx context.Context, req *authUserAPIAction) error {
+	resp, body, err := u.client.Do(ctx, req)
+	if err != nil {
+		return err
+	}
+	if err = assertStatusCode(resp.StatusCode, http.StatusOK, http.StatusCreated); err != nil {
+		var sec authError
+		err = json.Unmarshal(body, &sec)
+		if err != nil {
+			return err
+		}
+		return sec
+	}
+	return nil
+}
+
+func (u *httpAuthUserAPI) GetUser(ctx context.Context, username string) (*User, error) {
+	return u.modUser(ctx, &authUserAPIAction{
+		verb:     http.MethodGet,
+		username: username,
+	})
+}
+
+func (u *httpAuthUserAPI) GrantUser(ctx context.Context, username string, roles []string) (*User, error) {
+	user := &User{
+		User:  username,
+		Grant: roles,
+	}
+	return u.modUser(ctx, &authUserAPIAction{
+		verb:     http.MethodPut,
+		username: username,
+		user:     user,
+	})
+}
+
+func (u *httpAuthUserAPI) RevokeUser(ctx context.Context, username string, roles []string) (*User, error) {
+	user := &User{
+		User:   username,
+		Revoke: roles,
+	}
+	return u.modUser(ctx, &authUserAPIAction{
+		verb:     http.MethodPut,
+		username: username,
+		user:     user,
+	})
+}
+
+func (u *httpAuthUserAPI) ChangePassword(ctx context.Context, username string, password string) (*User, error) {
+	user := &User{
+		User:     username,
+		Password: password,
+	}
+	return u.modUser(ctx, &authUserAPIAction{
+		verb:     http.MethodPut,
+		username: username,
+		user:     user,
+	})
+}
+
+func (u *httpAuthUserAPI) modUser(ctx context.Context, req *authUserAPIAction) (*User, error) {
+	resp, body, err := u.client.Do(ctx, req)
+	if err != nil {
+		return nil, err
+	}
+	if err = assertStatusCode(resp.StatusCode, http.StatusOK); err != nil {
+		var sec authError
+		err = json.Unmarshal(body, &sec)
+		if err != nil {
+			return nil, err
+		}
+		return nil, sec
+	}
+	var user User
+	if err = json.Unmarshal(body, &user); err != nil {
+		var userR UserRoles
+		if urerr := json.Unmarshal(body, &userR); urerr != nil {
+			return nil, err
+		}
+		user.User = userR.User
+		for _, r := range userR.Roles {
+			user.Roles = append(user.Roles, r.Role)
+		}
+	}
+	return &user, nil
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/cancelreq.go b/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/cancelreq.go
new file mode 100644
index 0000000..23e5f89
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/cancelreq.go
@@ -0,0 +1,18 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// borrowed from golang/net/context/ctxhttp/cancelreq.go
+
+package client
+
+import "net/http"
+
+func requestCanceler(req *http.Request) func() {
+	ch := make(chan struct{})
+	req.Cancel = ch
+
+	return func() {
+		close(ch)
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/client.go b/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/client.go
new file mode 100644
index 0000000..598c2de
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/client.go
@@ -0,0 +1,719 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package client
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"math/rand"
+	"net"
+	"net/http"
+	"net/url"
+	"sort"
+	"strconv"
+	"sync"
+	"time"
+
+	"go.etcd.io/etcd/api/v3/version"
+)
+
+var (
+	ErrNoEndpoints           = errors.New("client: no endpoints available")
+	ErrTooManyRedirects      = errors.New("client: too many redirects")
+	ErrClusterUnavailable    = errors.New("client: etcd cluster is unavailable or misconfigured")
+	ErrNoLeaderEndpoint      = errors.New("client: no leader endpoint available")
+	errTooManyRedirectChecks = errors.New("client: too many redirect checks")
+
+	// oneShotCtxValue is set on a context using WithValue(&oneShotValue) so
+	// that Do() will not retry a request
+	oneShotCtxValue any
+)
+
+var DefaultRequestTimeout = 5 * time.Second
+
+var DefaultTransport CancelableTransport = &http.Transport{
+	Proxy: http.ProxyFromEnvironment,
+	DialContext: (&net.Dialer{
+		Timeout:   30 * time.Second,
+		KeepAlive: 30 * time.Second,
+	}).DialContext,
+	TLSHandshakeTimeout: 10 * time.Second,
+}
+
+type EndpointSelectionMode int
+
+const (
+	// EndpointSelectionRandom is the default value of the 'SelectionMode'.
+	// As the name implies, the client object will pick a node from the members
+	// of the cluster in a random fashion. If the cluster has three members, A, B,
+	// and C, the client picks any node from its three members as its request
+	// destination.
+	EndpointSelectionRandom EndpointSelectionMode = iota
+
+	// If 'SelectionMode' is set to 'EndpointSelectionPrioritizeLeader',
+	// requests are sent directly to the cluster leader. This reduces
+	// forwarding roundtrips compared to making requests to etcd followers
+	// who then forward them to the cluster leader. In the event of a leader
+	// failure, however, clients configured this way cannot prioritize among
+	// the remaining etcd followers. Therefore, when a client sets 'SelectionMode'
+	// to 'EndpointSelectionPrioritizeLeader', it must use 'client.AutoSync()' to
+	// maintain its knowledge of current cluster state.
+	//
+	// This mode should be used with Client.AutoSync().
+	EndpointSelectionPrioritizeLeader
+)
+
+type Config struct {
+	// Endpoints defines a set of URLs (schemes, hosts and ports only)
+	// that can be used to communicate with a logical etcd cluster. For
+	// example, a three-node cluster could be provided like so:
+	//
+	// 	Endpoints: []string{
+	//		"http://node1.example.com:2379",
+	//		"http://node2.example.com:2379",
+	//		"http://node3.example.com:2379",
+	//	}
+	//
+	// If multiple endpoints are provided, the Client will attempt to
+	// use them all in the event that one or more of them are unusable.
+	//
+	// If Client.Sync is ever called, the Client may cache an alternate
+	// set of endpoints to continue operation.
+	Endpoints []string
+
+	// Transport is used by the Client to drive HTTP requests. If not
+	// provided, DefaultTransport will be used.
+	Transport CancelableTransport
+
+	// CheckRedirect specifies the policy for handling HTTP redirects.
+	// If CheckRedirect is not nil, the Client calls it before
+	// following an HTTP redirect. The sole argument is the number of
+	// requests that have already been made. If CheckRedirect returns
+	// an error, Client.Do will not make any further requests and return
+	// the error back it to the caller.
+	//
+	// If CheckRedirect is nil, the Client uses its default policy,
+	// which is to stop after 10 consecutive requests.
+	CheckRedirect CheckRedirectFunc
+
+	// Username specifies the user credential to add as an authorization header
+	Username string
+
+	// Password is the password for the specified user to add as an authorization header
+	// to the request.
+	Password string
+
+	// HeaderTimeoutPerRequest specifies the time limit to wait for response
+	// header in a single request made by the Client. The timeout includes
+	// connection time, any redirects, and header wait time.
+	//
+	// For non-watch GET request, server returns the response body immediately.
+	// For PUT/POST/DELETE request, server will attempt to commit request
+	// before responding, which is expected to take `100ms + 2 * RTT`.
+	// For watch request, server returns the header immediately to notify Client
+	// watch start. But if server is behind some kind of proxy, the response
+	// header may be cached at proxy, and Client cannot rely on this behavior.
+	//
+	// Especially, wait request will ignore this timeout.
+	//
+	// One API call may send multiple requests to different etcd servers until it
+	// succeeds. Use context of the API to specify the overall timeout.
+	//
+	// A HeaderTimeoutPerRequest of zero means no timeout.
+	HeaderTimeoutPerRequest time.Duration
+
+	// SelectionMode is an EndpointSelectionMode enum that specifies the
+	// policy for choosing the etcd cluster node to which requests are sent.
+	SelectionMode EndpointSelectionMode
+}
+
+func (cfg *Config) transport() CancelableTransport {
+	if cfg.Transport == nil {
+		return DefaultTransport
+	}
+	return cfg.Transport
+}
+
+func (cfg *Config) checkRedirect() CheckRedirectFunc {
+	if cfg.CheckRedirect == nil {
+		return DefaultCheckRedirect
+	}
+	return cfg.CheckRedirect
+}
+
+// CancelableTransport mimics net/http.Transport, but requires that
+// the object also support request cancellation.
+type CancelableTransport interface {
+	http.RoundTripper
+	CancelRequest(req *http.Request)
+}
+
+type CheckRedirectFunc func(via int) error
+
+// DefaultCheckRedirect follows up to 10 redirects, but no more.
+var DefaultCheckRedirect CheckRedirectFunc = func(via int) error {
+	if via > 10 {
+		return ErrTooManyRedirects
+	}
+	return nil
+}
+
+type Client interface {
+	// Sync updates the internal cache of the etcd cluster's membership.
+	Sync(context.Context) error
+
+	// AutoSync periodically calls Sync() every given interval.
+	// The recommended sync interval is 10 seconds to 1 minute, which does
+	// not bring too much overhead to server and makes client catch up the
+	// cluster change in time.
+	//
+	// The example to use it:
+	//
+	//  for {
+	//      err := client.AutoSync(ctx, 10*time.Second)
+	//      if err == context.DeadlineExceeded || err == context.Canceled {
+	//          break
+	//      }
+	//      log.Print(err)
+	//  }
+	AutoSync(context.Context, time.Duration) error
+
+	// Endpoints returns a copy of the current set of API endpoints used
+	// by Client to resolve HTTP requests. If Sync has ever been called,
+	// this may differ from the initial Endpoints provided in the Config.
+	Endpoints() []string
+
+	// SetEndpoints sets the set of API endpoints used by Client to resolve
+	// HTTP requests. If the given endpoints are not valid, an error will be
+	// returned
+	SetEndpoints(eps []string) error
+
+	// GetVersion retrieves the current etcd server and cluster version
+	GetVersion(ctx context.Context) (*version.Versions, error)
+
+	httpClient
+}
+
+func New(cfg Config) (Client, error) {
+	c := &httpClusterClient{
+		clientFactory: newHTTPClientFactory(cfg.transport(), cfg.checkRedirect(), cfg.HeaderTimeoutPerRequest),
+		rand:          rand.New(rand.NewSource(int64(time.Now().Nanosecond()))),
+		selectionMode: cfg.SelectionMode,
+	}
+	if cfg.Username != "" {
+		c.credentials = &credentials{
+			username: cfg.Username,
+			password: cfg.Password,
+		}
+	}
+	if err := c.SetEndpoints(cfg.Endpoints); err != nil {
+		return nil, err
+	}
+	return c, nil
+}
+
+type httpClient interface {
+	Do(context.Context, httpAction) (*http.Response, []byte, error)
+}
+
+func newHTTPClientFactory(tr CancelableTransport, cr CheckRedirectFunc, headerTimeout time.Duration) httpClientFactory {
+	return func(ep url.URL) httpClient {
+		return &redirectFollowingHTTPClient{
+			checkRedirect: cr,
+			client: &simpleHTTPClient{
+				transport:     tr,
+				endpoint:      ep,
+				headerTimeout: headerTimeout,
+			},
+		}
+	}
+}
+
+type credentials struct {
+	username string
+	password string
+}
+
+type httpClientFactory func(url.URL) httpClient
+
+type httpAction interface {
+	HTTPRequest(url.URL) *http.Request
+}
+
+type httpClusterClient struct {
+	clientFactory httpClientFactory
+	endpoints     []url.URL
+	pinned        int
+	credentials   *credentials
+	sync.RWMutex
+	rand          *rand.Rand
+	selectionMode EndpointSelectionMode
+}
+
+func (c *httpClusterClient) getLeaderEndpoint(ctx context.Context, eps []url.URL) (string, error) {
+	ceps := make([]url.URL, len(eps))
+	copy(ceps, eps)
+
+	// To perform a lookup on the new endpoint list without using the current
+	// client, we'll copy it
+	clientCopy := &httpClusterClient{
+		clientFactory: c.clientFactory,
+		credentials:   c.credentials,
+		rand:          c.rand,
+
+		pinned:    0,
+		endpoints: ceps,
+	}
+
+	mAPI := NewMembersAPI(clientCopy)
+	leader, err := mAPI.Leader(ctx)
+	if err != nil {
+		return "", err
+	}
+	if len(leader.ClientURLs) == 0 {
+		return "", ErrNoLeaderEndpoint
+	}
+
+	return leader.ClientURLs[0], nil // TODO: how to handle multiple client URLs?
+}
+
+func (c *httpClusterClient) parseEndpoints(eps []string) ([]url.URL, error) {
+	if len(eps) == 0 {
+		return []url.URL{}, ErrNoEndpoints
+	}
+
+	neps := make([]url.URL, len(eps))
+	for i, ep := range eps {
+		u, err := url.Parse(ep)
+		if err != nil {
+			return []url.URL{}, err
+		}
+		neps[i] = *u
+	}
+	return neps, nil
+}
+
+func (c *httpClusterClient) SetEndpoints(eps []string) error {
+	neps, err := c.parseEndpoints(eps)
+	if err != nil {
+		return err
+	}
+
+	c.Lock()
+	defer c.Unlock()
+
+	c.endpoints = shuffleEndpoints(c.rand, neps)
+	// We're not doing anything for PrioritizeLeader here. This is
+	// due to not having a context meaning we can't call getLeaderEndpoint
+	// However, if you're using PrioritizeLeader, you've already been told
+	// to regularly call sync, where we do have a ctx, and can figure the
+	// leader. PrioritizeLeader is also quite a loose guarantee, so deal
+	// with it
+	c.pinned = 0
+
+	return nil
+}
+
+func (c *httpClusterClient) Do(ctx context.Context, act httpAction) (*http.Response, []byte, error) {
+	action := act
+	c.RLock()
+	leps := len(c.endpoints)
+	eps := make([]url.URL, leps)
+	n := copy(eps, c.endpoints)
+	pinned := c.pinned
+
+	if c.credentials != nil {
+		action = &authedAction{
+			act:         act,
+			credentials: *c.credentials,
+		}
+	}
+	c.RUnlock()
+
+	if leps == 0 {
+		return nil, nil, ErrNoEndpoints
+	}
+
+	if leps != n {
+		return nil, nil, errors.New("unable to pick endpoint: copy failed")
+	}
+
+	var resp *http.Response
+	var body []byte
+	var err error
+	cerr := &ClusterError{}
+	isOneShot := ctx.Value(&oneShotCtxValue) != nil
+
+	for i := pinned; i < leps+pinned; i++ {
+		k := i % leps
+		hc := c.clientFactory(eps[k])
+		resp, body, err = hc.Do(ctx, action)
+		if err != nil {
+			cerr.Errors = append(cerr.Errors, err)
+			if errors.Is(err, ctx.Err()) {
+				return nil, nil, ctx.Err()
+			}
+			if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
+				return nil, nil, err
+			}
+		} else if resp.StatusCode/100 == 5 {
+			switch resp.StatusCode {
+			case http.StatusInternalServerError, http.StatusServiceUnavailable:
+				// TODO: make sure this is a no leader response
+				cerr.Errors = append(cerr.Errors, fmt.Errorf("client: etcd member %s has no leader", eps[k].String()))
+			default:
+				cerr.Errors = append(cerr.Errors, fmt.Errorf("client: etcd member %s returns server error [%s]", eps[k].String(), http.StatusText(resp.StatusCode)))
+			}
+			err = cerr.Errors[0]
+		}
+		if err != nil {
+			if !isOneShot {
+				continue
+			}
+			c.Lock()
+			c.pinned = (k + 1) % leps
+			c.Unlock()
+			return nil, nil, err
+		}
+		if k != pinned {
+			c.Lock()
+			c.pinned = k
+			c.Unlock()
+		}
+		return resp, body, nil
+	}
+
+	return nil, nil, cerr
+}
+
+func (c *httpClusterClient) Endpoints() []string {
+	c.RLock()
+	defer c.RUnlock()
+
+	eps := make([]string, len(c.endpoints))
+	for i, ep := range c.endpoints {
+		eps[i] = ep.String()
+	}
+
+	return eps
+}
+
+func (c *httpClusterClient) Sync(ctx context.Context) error {
+	mAPI := NewMembersAPI(c)
+	ms, err := mAPI.List(ctx)
+	if err != nil {
+		return err
+	}
+
+	var eps []string
+	for _, m := range ms {
+		eps = append(eps, m.ClientURLs...)
+	}
+
+	neps, err := c.parseEndpoints(eps)
+	if err != nil {
+		return err
+	}
+
+	npin := 0
+
+	switch c.selectionMode {
+	case EndpointSelectionRandom:
+		c.RLock()
+		eq := endpointsEqual(c.endpoints, neps)
+		c.RUnlock()
+
+		if eq {
+			return nil
+		}
+		// When items in the endpoint list changes, we choose a new pin
+		neps = shuffleEndpoints(c.rand, neps)
+	case EndpointSelectionPrioritizeLeader:
+		nle, err := c.getLeaderEndpoint(ctx, neps)
+		if err != nil {
+			return ErrNoLeaderEndpoint
+		}
+
+		for i, n := range neps {
+			if n.String() == nle {
+				npin = i
+				break
+			}
+		}
+	default:
+		return fmt.Errorf("invalid endpoint selection mode: %d", c.selectionMode)
+	}
+
+	c.Lock()
+	defer c.Unlock()
+	c.endpoints = neps
+	c.pinned = npin
+
+	return nil
+}
+
+func (c *httpClusterClient) AutoSync(ctx context.Context, interval time.Duration) error {
+	ticker := time.NewTicker(interval)
+	defer ticker.Stop()
+	for {
+		err := c.Sync(ctx)
+		if err != nil {
+			return err
+		}
+		select {
+		case <-ctx.Done():
+			return ctx.Err()
+		case <-ticker.C:
+		}
+	}
+}
+
+func (c *httpClusterClient) GetVersion(ctx context.Context) (*version.Versions, error) {
+	act := &getAction{Prefix: "/version"}
+
+	resp, body, err := c.Do(ctx, act)
+	if err != nil {
+		return nil, err
+	}
+
+	switch resp.StatusCode {
+	case http.StatusOK:
+		if len(body) == 0 {
+			return nil, ErrEmptyBody
+		}
+		var vresp version.Versions
+		if err := json.Unmarshal(body, &vresp); err != nil {
+			return nil, ErrInvalidJSON
+		}
+		return &vresp, nil
+	default:
+		var etcdErr Error
+		if err := json.Unmarshal(body, &etcdErr); err != nil {
+			return nil, ErrInvalidJSON
+		}
+		return nil, etcdErr
+	}
+}
+
+type roundTripResponse struct {
+	resp *http.Response
+	err  error
+}
+
+type simpleHTTPClient struct {
+	transport     CancelableTransport
+	endpoint      url.URL
+	headerTimeout time.Duration
+}
+
+// ErrNoRequest indicates that the HTTPRequest object could not be found
+// or was nil.  No processing could continue.
+var ErrNoRequest = errors.New("no HTTPRequest was available")
+
+func (c *simpleHTTPClient) Do(ctx context.Context, act httpAction) (*http.Response, []byte, error) {
+	req := act.HTTPRequest(c.endpoint)
+	if req == nil {
+		return nil, nil, ErrNoRequest
+	}
+
+	if err := printcURL(req); err != nil {
+		return nil, nil, err
+	}
+
+	isWait := false
+	if req.URL != nil {
+		ws := req.URL.Query().Get("wait")
+		if len(ws) != 0 {
+			var err error
+			isWait, err = strconv.ParseBool(ws)
+			if err != nil {
+				return nil, nil, fmt.Errorf("wrong wait value %s (%w for %+v)", ws, err, req)
+			}
+		}
+	}
+
+	var hctx context.Context
+	var hcancel context.CancelFunc
+	if !isWait && c.headerTimeout > 0 {
+		hctx, hcancel = context.WithTimeout(ctx, c.headerTimeout)
+	} else {
+		hctx, hcancel = context.WithCancel(ctx)
+	}
+	defer hcancel()
+
+	reqcancel := requestCanceler(req)
+
+	rtchan := make(chan roundTripResponse, 1)
+	go func() {
+		resp, err := c.transport.RoundTrip(req)
+		rtchan <- roundTripResponse{resp: resp, err: err}
+		close(rtchan)
+	}()
+
+	var resp *http.Response
+	var err error
+
+	select {
+	case rtresp := <-rtchan:
+		resp, err = rtresp.resp, rtresp.err
+	case <-hctx.Done():
+		// cancel and wait for request to actually exit before continuing
+		reqcancel()
+		rtresp := <-rtchan
+		resp = rtresp.resp
+		switch {
+		case ctx.Err() != nil:
+			err = ctx.Err()
+		case hctx.Err() != nil:
+			err = fmt.Errorf("client: endpoint %s exceeded header timeout", c.endpoint.String())
+		default:
+			panic("failed to get error from context")
+		}
+	}
+
+	// always check for resp nil-ness to deal with possible
+	// race conditions between channels above
+	defer func() {
+		if resp != nil {
+			resp.Body.Close()
+		}
+	}()
+
+	if err != nil {
+		return nil, nil, err
+	}
+
+	var body []byte
+	done := make(chan struct{})
+	go func() {
+		body, err = io.ReadAll(resp.Body)
+		done <- struct{}{}
+	}()
+
+	select {
+	case <-ctx.Done():
+		if resp != nil {
+			resp.Body.Close()
+		}
+		<-done
+		return nil, nil, ctx.Err()
+	case <-done:
+	}
+
+	return resp, body, err
+}
+
+type authedAction struct {
+	act         httpAction
+	credentials credentials
+}
+
+func (a *authedAction) HTTPRequest(url url.URL) *http.Request {
+	r := a.act.HTTPRequest(url)
+	r.SetBasicAuth(a.credentials.username, a.credentials.password)
+	return r
+}
+
+type redirectFollowingHTTPClient struct {
+	client        httpClient
+	checkRedirect CheckRedirectFunc
+}
+
+func (r *redirectFollowingHTTPClient) Do(ctx context.Context, act httpAction) (*http.Response, []byte, error) {
+	next := act
+	for i := 0; i < 100; i++ {
+		if i > 0 {
+			if err := r.checkRedirect(i); err != nil {
+				return nil, nil, err
+			}
+		}
+		resp, body, err := r.client.Do(ctx, next)
+		if err != nil {
+			return nil, nil, err
+		}
+		if resp.StatusCode/100 == 3 {
+			hdr := resp.Header.Get("Location")
+			if hdr == "" {
+				return nil, nil, errors.New("location header not set")
+			}
+			loc, err := url.Parse(hdr)
+			if err != nil {
+				return nil, nil, fmt.Errorf("location header not valid URL: %s", hdr)
+			}
+			next = &redirectedHTTPAction{
+				action:   act,
+				location: *loc,
+			}
+			continue
+		}
+		return resp, body, nil
+	}
+
+	return nil, nil, errTooManyRedirectChecks
+}
+
+type redirectedHTTPAction struct {
+	action   httpAction
+	location url.URL
+}
+
+func (r *redirectedHTTPAction) HTTPRequest(ep url.URL) *http.Request {
+	orig := r.action.HTTPRequest(ep)
+	orig.URL = &r.location
+	return orig
+}
+
+func shuffleEndpoints(r *rand.Rand, eps []url.URL) []url.URL {
+	// copied from Go 1.9<= rand.Rand.Perm
+	n := len(eps)
+	p := make([]int, n)
+	for i := 0; i < n; i++ {
+		j := r.Intn(i + 1)
+		p[i] = p[j]
+		p[j] = i
+	}
+	neps := make([]url.URL, n)
+	for i, k := range p {
+		neps[i] = eps[k]
+	}
+	return neps
+}
+
+func endpointsEqual(left, right []url.URL) bool {
+	if len(left) != len(right) {
+		return false
+	}
+
+	sLeft := make([]string, len(left))
+	sRight := make([]string, len(right))
+	for i, l := range left {
+		sLeft[i] = l.String()
+	}
+	for i, r := range right {
+		sRight[i] = r.String()
+	}
+
+	sort.Strings(sLeft)
+	sort.Strings(sRight)
+	for i := range sLeft {
+		if sLeft[i] != sRight[i] {
+			return false
+		}
+	}
+	return true
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/cluster_error.go b/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/cluster_error.go
new file mode 100644
index 0000000..34618cd
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/cluster_error.go
@@ -0,0 +1,37 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package client
+
+import "fmt"
+
+type ClusterError struct {
+	Errors []error
+}
+
+func (ce *ClusterError) Error() string {
+	s := ErrClusterUnavailable.Error()
+	for i, e := range ce.Errors {
+		s += fmt.Sprintf("; error #%d: %s\n", i, e)
+	}
+	return s
+}
+
+func (ce *ClusterError) Detail() string {
+	s := ""
+	for i, e := range ce.Errors {
+		s += fmt.Sprintf("error #%d: %s\n", i, e)
+	}
+	return s
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/curl.go b/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/curl.go
new file mode 100644
index 0000000..5d5dc57
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/curl.go
@@ -0,0 +1,68 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package client
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+)
+
+var cURLDebug = false
+
+func EnablecURLDebug() {
+	cURLDebug = true
+}
+
+func DisablecURLDebug() {
+	cURLDebug = false
+}
+
+// printcURL prints the cURL equivalent request to stderr.
+// It returns an error if the body of the request cannot
+// be read.
+// The caller MUST cancel the request if there is an error.
+func printcURL(req *http.Request) error {
+	if !cURLDebug {
+		return nil
+	}
+	var (
+		command string
+		b       []byte
+		err     error
+	)
+
+	if req.URL != nil {
+		command = fmt.Sprintf("curl -X %s %s", req.Method, req.URL.String())
+	}
+
+	if req.Body != nil {
+		b, err = io.ReadAll(req.Body)
+		if err != nil {
+			return err
+		}
+		command += fmt.Sprintf(" -d %q", string(b))
+	}
+
+	fmt.Fprintf(os.Stderr, "cURL Command: %q\n", command)
+
+	// reset body
+	body := bytes.NewBuffer(b)
+	req.Body = io.NopCloser(body)
+
+	return nil
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/discover.go b/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/discover.go
new file mode 100644
index 0000000..646ba5d
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/discover.go
@@ -0,0 +1,40 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package client
+
+import (
+	"go.etcd.io/etcd/client/pkg/v3/srv"
+)
+
+// Discoverer is an interface that wraps the Discover method.
+type Discoverer interface {
+	// Discover looks up the etcd servers for the domain.
+	Discover(domain string, serviceName string) ([]string, error)
+}
+
+type srvDiscover struct{}
+
+// NewSRVDiscover constructs a new Discoverer that uses the stdlib to lookup SRV records.
+func NewSRVDiscover() Discoverer {
+	return &srvDiscover{}
+}
+
+func (d *srvDiscover) Discover(domain string, serviceName string) ([]string, error) {
+	srvs, err := srv.GetClient("etcd-client", domain, serviceName)
+	if err != nil {
+		return nil, err
+	}
+	return srvs.Endpoints, nil
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/doc.go b/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/doc.go
new file mode 100644
index 0000000..68284c2
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/doc.go
@@ -0,0 +1,72 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/*
+Package client provides bindings for the etcd APIs.
+
+Create a Config and exchange it for a Client:
+
+	import (
+		"net/http"
+		"context"
+
+		"go.etcd.io/etcd/client/v2"
+	)
+
+	cfg := client.Config{
+		Endpoints: []string{"http://127.0.0.1:2379"},
+		Transport: DefaultTransport,
+	}
+
+	c, err := client.New(cfg)
+	if err != nil {
+		// handle error
+	}
+
+Clients are safe for concurrent use by multiple goroutines.
+
+Create a KeysAPI using the Client, then use it to interact with etcd:
+
+	kAPI := client.NewKeysAPI(c)
+
+	// create a new key /foo with the value "bar"
+	_, err = kAPI.Create(context.Background(), "/foo", "bar")
+	if err != nil {
+		// handle error
+	}
+
+	// delete the newly created key only if the value is still "bar"
+	_, err = kAPI.Delete(context.Background(), "/foo", &DeleteOptions{PrevValue: "bar"})
+	if err != nil {
+		// handle error
+	}
+
+Use a custom context to set timeouts on your operations:
+
+	import "time"
+
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	// set a new key, ignoring its previous state
+	_, err := kAPI.Set(ctx, "/ping", "pong", nil)
+	if err != nil {
+		if err == context.DeadlineExceeded {
+			// request took longer than 5s
+		} else {
+			// handle error
+		}
+	}
+*/
+package client
diff --git a/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/keys.go b/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/keys.go
new file mode 100644
index 0000000..87783cd
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/keys.go
@@ -0,0 +1,678 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package client
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"net/http"
+	"net/url"
+	"strconv"
+	"strings"
+	"time"
+
+	kjson "sigs.k8s.io/json"
+
+	"go.etcd.io/etcd/client/pkg/v3/pathutil"
+)
+
+const (
+	ErrorCodeKeyNotFound  = 100
+	ErrorCodeTestFailed   = 101
+	ErrorCodeNotFile      = 102
+	ErrorCodeNotDir       = 104
+	ErrorCodeNodeExist    = 105
+	ErrorCodeRootROnly    = 107
+	ErrorCodeDirNotEmpty  = 108
+	ErrorCodeUnauthorized = 110
+
+	ErrorCodePrevValueRequired = 201
+	ErrorCodeTTLNaN            = 202
+	ErrorCodeIndexNaN          = 203
+	ErrorCodeInvalidField      = 209
+	ErrorCodeInvalidForm       = 210
+
+	ErrorCodeRaftInternal = 300
+	ErrorCodeLeaderElect  = 301
+
+	ErrorCodeWatcherCleared    = 400
+	ErrorCodeEventIndexCleared = 401
+)
+
+type Error struct {
+	Code    int    `json:"errorCode"`
+	Message string `json:"message"`
+	Cause   string `json:"cause"`
+	Index   uint64 `json:"index"`
+}
+
+func (e Error) Error() string {
+	return fmt.Sprintf("%v: %v (%v) [%v]", e.Code, e.Message, e.Cause, e.Index)
+}
+
+var (
+	ErrInvalidJSON = errors.New("client: response is invalid json. The endpoint is probably not valid etcd cluster endpoint")
+	ErrEmptyBody   = errors.New("client: response body is empty")
+)
+
+// PrevExistType is used to define an existence condition when setting
+// or deleting Nodes.
+type PrevExistType string
+
+const (
+	PrevIgnore  = PrevExistType("")
+	PrevExist   = PrevExistType("true")
+	PrevNoExist = PrevExistType("false")
+)
+
+var defaultV2KeysPrefix = "/v2/keys"
+
+// NewKeysAPI builds a KeysAPI that interacts with etcd's key-value
+// API over HTTP.
+func NewKeysAPI(c Client) KeysAPI {
+	return NewKeysAPIWithPrefix(c, defaultV2KeysPrefix)
+}
+
+// NewKeysAPIWithPrefix acts like NewKeysAPI, but allows the caller
+// to provide a custom base URL path. This should only be used in
+// very rare cases.
+func NewKeysAPIWithPrefix(c Client, p string) KeysAPI {
+	return &httpKeysAPI{
+		client: c,
+		prefix: p,
+	}
+}
+
+type KeysAPI interface {
+	// Get retrieves a set of Nodes from etcd
+	Get(ctx context.Context, key string, opts *GetOptions) (*Response, error)
+
+	// Set assigns a new value to a Node identified by a given key. The caller
+	// may define a set of conditions in the SetOptions. If SetOptions.Dir=true
+	// then value is ignored.
+	Set(ctx context.Context, key, value string, opts *SetOptions) (*Response, error)
+
+	// Delete removes a Node identified by the given key, optionally destroying
+	// all of its children as well. The caller may define a set of required
+	// conditions in an DeleteOptions object.
+	Delete(ctx context.Context, key string, opts *DeleteOptions) (*Response, error)
+
+	// Create is an alias for Set w/ PrevExist=false
+	Create(ctx context.Context, key, value string) (*Response, error)
+
+	// CreateInOrder is used to atomically create in-order keys within the given directory.
+	CreateInOrder(ctx context.Context, dir, value string, opts *CreateInOrderOptions) (*Response, error)
+
+	// Update is an alias for Set w/ PrevExist=true
+	Update(ctx context.Context, key, value string) (*Response, error)
+
+	// Watcher builds a new Watcher targeted at a specific Node identified
+	// by the given key. The Watcher may be configured at creation time
+	// through a WatcherOptions object. The returned Watcher is designed
+	// to emit events that happen to a Node, and optionally to its children.
+	Watcher(key string, opts *WatcherOptions) Watcher
+}
+
+type WatcherOptions struct {
+	// AfterIndex defines the index after-which the Watcher should
+	// start emitting events. For example, if a value of 5 is
+	// provided, the first event will have an index >= 6.
+	//
+	// Setting AfterIndex to 0 (default) means that the Watcher
+	// should start watching for events starting at the current
+	// index, whatever that may be.
+	AfterIndex uint64
+
+	// Recursive specifies whether or not the Watcher should emit
+	// events that occur in children of the given keyspace. If set
+	// to false (default), events will be limited to those that
+	// occur for the exact key.
+	Recursive bool
+}
+
+type CreateInOrderOptions struct {
+	// TTL defines a period of time after-which the Node should
+	// expire and no longer exist. Values <= 0 are ignored. Given
+	// that the zero-value is ignored, TTL cannot be used to set
+	// a TTL of 0.
+	TTL time.Duration
+}
+
+type SetOptions struct {
+	// PrevValue specifies what the current value of the Node must
+	// be in order for the Set operation to succeed.
+	//
+	// Leaving this field empty means that the caller wishes to
+	// ignore the current value of the Node. This cannot be used
+	// to compare the Node's current value to an empty string.
+	//
+	// PrevValue is ignored if Dir=true
+	PrevValue string
+
+	// PrevIndex indicates what the current ModifiedIndex of the
+	// Node must be in order for the Set operation to succeed.
+	//
+	// If PrevIndex is set to 0 (default), no comparison is made.
+	PrevIndex uint64
+
+	// PrevExist specifies whether the Node must currently exist
+	// (PrevExist) or not (PrevNoExist). If the caller does not
+	// care about existence, set PrevExist to PrevIgnore, or simply
+	// leave it unset.
+	PrevExist PrevExistType
+
+	// TTL defines a period of time after-which the Node should
+	// expire and no longer exist. Values <= 0 are ignored. Given
+	// that the zero-value is ignored, TTL cannot be used to set
+	// a TTL of 0.
+	TTL time.Duration
+
+	// Refresh set to true means a TTL value can be updated
+	// without firing a watch or changing the node value. A
+	// value must not be provided when refreshing a key.
+	Refresh bool
+
+	// Dir specifies whether or not this Node should be created as a directory.
+	Dir bool
+
+	// NoValueOnSuccess specifies whether the response contains the current value of the Node.
+	// If set, the response will only contain the current value when the request fails.
+	NoValueOnSuccess bool
+}
+
+type GetOptions struct {
+	// Recursive defines whether or not all children of the Node
+	// should be returned.
+	Recursive bool
+
+	// Sort instructs the server whether or not to sort the Nodes.
+	// If true, the Nodes are sorted alphabetically by key in
+	// ascending order (A to z). If false (default), the Nodes will
+	// not be sorted and the ordering used should not be considered
+	// predictable.
+	Sort bool
+
+	// Quorum specifies whether it gets the latest committed value that
+	// has been applied in quorum of members, which ensures external
+	// consistency (or linearizability).
+	Quorum bool
+}
+
+type DeleteOptions struct {
+	// PrevValue specifies what the current value of the Node must
+	// be in order for the Delete operation to succeed.
+	//
+	// Leaving this field empty means that the caller wishes to
+	// ignore the current value of the Node. This cannot be used
+	// to compare the Node's current value to an empty string.
+	PrevValue string
+
+	// PrevIndex indicates what the current ModifiedIndex of the
+	// Node must be in order for the Delete operation to succeed.
+	//
+	// If PrevIndex is set to 0 (default), no comparison is made.
+	PrevIndex uint64
+
+	// Recursive defines whether or not all children of the Node
+	// should be deleted. If set to true, all children of the Node
+	// identified by the given key will be deleted. If left unset
+	// or explicitly set to false, only a single Node will be
+	// deleted.
+	Recursive bool
+
+	// Dir specifies whether or not this Node should be removed as a directory.
+	Dir bool
+}
+
+type Watcher interface {
+	// Next blocks until an etcd event occurs, then returns a Response
+	// representing that event. The behavior of Next depends on the
+	// WatcherOptions used to construct the Watcher. Next is designed to
+	// be called repeatedly, each time blocking until a subsequent event
+	// is available.
+	//
+	// If the provided context is cancelled, Next will return a non-nil
+	// error. Any other failures encountered while waiting for the next
+	// event (connection issues, deserialization failures, etc) will
+	// also result in a non-nil error.
+	Next(context.Context) (*Response, error)
+}
+
+type Response struct {
+	// Action is the name of the operation that occurred. Possible values
+	// include get, set, delete, update, create, compareAndSwap,
+	// compareAndDelete and expire.
+	Action string `json:"action"`
+
+	// Node represents the state of the relevant etcd Node.
+	Node *Node `json:"node"`
+
+	// PrevNode represents the previous state of the Node. PrevNode is non-nil
+	// only if the Node existed before the action occurred and the action
+	// caused a change to the Node.
+	PrevNode *Node `json:"prevNode"`
+
+	// Index holds the cluster-level index at the time the Response was generated.
+	// This index is not tied to the Node(s) contained in this Response.
+	Index uint64 `json:"-"`
+
+	// ClusterID holds the cluster-level ID reported by the server.  This
+	// should be different for different etcd clusters.
+	ClusterID string `json:"-"`
+}
+
+type Node struct {
+	// Key represents the unique location of this Node (e.g. "/foo/bar").
+	Key string `json:"key"`
+
+	// Dir reports whether node describes a directory.
+	Dir bool `json:"dir,omitempty"`
+
+	// Value is the current data stored on this Node. If this Node
+	// is a directory, Value will be empty.
+	Value string `json:"value"`
+
+	// Nodes holds the children of this Node, only if this Node is a directory.
+	// This slice of will be arbitrarily deep (children, grandchildren, great-
+	// grandchildren, etc.) if a recursive Get or Watch request were made.
+	Nodes Nodes `json:"nodes"`
+
+	// CreatedIndex is the etcd index at-which this Node was created.
+	CreatedIndex uint64 `json:"createdIndex"`
+
+	// ModifiedIndex is the etcd index at-which this Node was last modified.
+	ModifiedIndex uint64 `json:"modifiedIndex"`
+
+	// Expiration is the server side expiration time of the key.
+	Expiration *time.Time `json:"expiration,omitempty"`
+
+	// TTL is the time to live of the key in second.
+	TTL int64 `json:"ttl,omitempty"`
+}
+
+func (n *Node) String() string {
+	return fmt.Sprintf("{Key: %s, CreatedIndex: %d, ModifiedIndex: %d, TTL: %d}", n.Key, n.CreatedIndex, n.ModifiedIndex, n.TTL)
+}
+
+// TTLDuration returns the Node's TTL as a time.Duration object
+func (n *Node) TTLDuration() time.Duration {
+	return time.Duration(n.TTL) * time.Second
+}
+
+type Nodes []*Node
+
+// interfaces for sorting
+
+func (ns Nodes) Len() int           { return len(ns) }
+func (ns Nodes) Less(i, j int) bool { return ns[i].Key < ns[j].Key }
+func (ns Nodes) Swap(i, j int)      { ns[i], ns[j] = ns[j], ns[i] }
+
+type httpKeysAPI struct {
+	client httpClient
+	prefix string
+}
+
+func (k *httpKeysAPI) Set(ctx context.Context, key, val string, opts *SetOptions) (*Response, error) {
+	act := &setAction{
+		Prefix: k.prefix,
+		Key:    key,
+		Value:  val,
+	}
+
+	if opts != nil {
+		act.PrevValue = opts.PrevValue
+		act.PrevIndex = opts.PrevIndex
+		act.PrevExist = opts.PrevExist
+		act.TTL = opts.TTL
+		act.Refresh = opts.Refresh
+		act.Dir = opts.Dir
+		act.NoValueOnSuccess = opts.NoValueOnSuccess
+	}
+
+	doCtx := ctx
+	if act.PrevExist == PrevNoExist {
+		doCtx = context.WithValue(doCtx, &oneShotCtxValue, &oneShotCtxValue)
+	}
+	resp, body, err := k.client.Do(doCtx, act)
+	if err != nil {
+		return nil, err
+	}
+
+	return unmarshalHTTPResponse(resp.StatusCode, resp.Header, body)
+}
+
+func (k *httpKeysAPI) Create(ctx context.Context, key, val string) (*Response, error) {
+	return k.Set(ctx, key, val, &SetOptions{PrevExist: PrevNoExist})
+}
+
+func (k *httpKeysAPI) CreateInOrder(ctx context.Context, dir, val string, opts *CreateInOrderOptions) (*Response, error) {
+	act := &createInOrderAction{
+		Prefix: k.prefix,
+		Dir:    dir,
+		Value:  val,
+	}
+
+	if opts != nil {
+		act.TTL = opts.TTL
+	}
+
+	resp, body, err := k.client.Do(ctx, act)
+	if err != nil {
+		return nil, err
+	}
+
+	return unmarshalHTTPResponse(resp.StatusCode, resp.Header, body)
+}
+
+func (k *httpKeysAPI) Update(ctx context.Context, key, val string) (*Response, error) {
+	return k.Set(ctx, key, val, &SetOptions{PrevExist: PrevExist})
+}
+
+func (k *httpKeysAPI) Delete(ctx context.Context, key string, opts *DeleteOptions) (*Response, error) {
+	act := &deleteAction{
+		Prefix: k.prefix,
+		Key:    key,
+	}
+
+	if opts != nil {
+		act.PrevValue = opts.PrevValue
+		act.PrevIndex = opts.PrevIndex
+		act.Dir = opts.Dir
+		act.Recursive = opts.Recursive
+	}
+
+	doCtx := context.WithValue(ctx, &oneShotCtxValue, &oneShotCtxValue)
+	resp, body, err := k.client.Do(doCtx, act)
+	if err != nil {
+		return nil, err
+	}
+
+	return unmarshalHTTPResponse(resp.StatusCode, resp.Header, body)
+}
+
+func (k *httpKeysAPI) Get(ctx context.Context, key string, opts *GetOptions) (*Response, error) {
+	act := &getAction{
+		Prefix: k.prefix,
+		Key:    key,
+	}
+
+	if opts != nil {
+		act.Recursive = opts.Recursive
+		act.Sorted = opts.Sort
+		act.Quorum = opts.Quorum
+	}
+
+	resp, body, err := k.client.Do(ctx, act)
+	if err != nil {
+		return nil, err
+	}
+
+	return unmarshalHTTPResponse(resp.StatusCode, resp.Header, body)
+}
+
+func (k *httpKeysAPI) Watcher(key string, opts *WatcherOptions) Watcher {
+	act := waitAction{
+		Prefix: k.prefix,
+		Key:    key,
+	}
+
+	if opts != nil {
+		act.Recursive = opts.Recursive
+		if opts.AfterIndex > 0 {
+			act.WaitIndex = opts.AfterIndex + 1
+		}
+	}
+
+	return &httpWatcher{
+		client:   k.client,
+		nextWait: act,
+	}
+}
+
+type httpWatcher struct {
+	client   httpClient
+	nextWait waitAction
+}
+
+func (hw *httpWatcher) Next(ctx context.Context) (*Response, error) {
+	for {
+		httpresp, body, err := hw.client.Do(ctx, &hw.nextWait)
+		if err != nil {
+			return nil, err
+		}
+
+		resp, err := unmarshalHTTPResponse(httpresp.StatusCode, httpresp.Header, body)
+		if err != nil {
+			if errors.Is(err, ErrEmptyBody) {
+				continue
+			}
+			return nil, err
+		}
+
+		hw.nextWait.WaitIndex = resp.Node.ModifiedIndex + 1
+		return resp, nil
+	}
+}
+
+// v2KeysURL forms a URL representing the location of a key.
+// The endpoint argument represents the base URL of an etcd
+// server. The prefix is the path needed to route from the
+// provided endpoint's path to the root of the keys API
+// (typically "/v2/keys").
+func v2KeysURL(ep url.URL, prefix, key string) *url.URL {
+	// We concatenate all parts together manually. We cannot use
+	// path.Join because it does not reserve trailing slash.
+	// We call CanonicalURLPath to further cleanup the path.
+	if prefix != "" && prefix[0] != '/' {
+		prefix = "/" + prefix
+	}
+	if key != "" && key[0] != '/' {
+		key = "/" + key
+	}
+	ep.Path = pathutil.CanonicalURLPath(ep.Path + prefix + key)
+	return &ep
+}
+
+type getAction struct {
+	Prefix    string
+	Key       string
+	Recursive bool
+	Sorted    bool
+	Quorum    bool
+}
+
+func (g *getAction) HTTPRequest(ep url.URL) *http.Request {
+	u := v2KeysURL(ep, g.Prefix, g.Key)
+
+	params := u.Query()
+	params.Set("recursive", strconv.FormatBool(g.Recursive))
+	params.Set("sorted", strconv.FormatBool(g.Sorted))
+	params.Set("quorum", strconv.FormatBool(g.Quorum))
+	u.RawQuery = params.Encode()
+
+	req, _ := http.NewRequest(http.MethodGet, u.String(), nil)
+	return req
+}
+
+type waitAction struct {
+	Prefix    string
+	Key       string
+	WaitIndex uint64
+	Recursive bool
+}
+
+func (w *waitAction) HTTPRequest(ep url.URL) *http.Request {
+	u := v2KeysURL(ep, w.Prefix, w.Key)
+
+	params := u.Query()
+	params.Set("wait", "true")
+	params.Set("waitIndex", strconv.FormatUint(w.WaitIndex, 10))
+	params.Set("recursive", strconv.FormatBool(w.Recursive))
+	u.RawQuery = params.Encode()
+
+	req, _ := http.NewRequest(http.MethodGet, u.String(), nil)
+	return req
+}
+
+type setAction struct {
+	Prefix           string
+	Key              string
+	Value            string
+	PrevValue        string
+	PrevIndex        uint64
+	PrevExist        PrevExistType
+	TTL              time.Duration
+	Refresh          bool
+	Dir              bool
+	NoValueOnSuccess bool
+}
+
+func (a *setAction) HTTPRequest(ep url.URL) *http.Request {
+	u := v2KeysURL(ep, a.Prefix, a.Key)
+
+	params := u.Query()
+	form := url.Values{}
+
+	// we're either creating a directory or setting a key
+	if a.Dir {
+		params.Set("dir", strconv.FormatBool(a.Dir))
+	} else {
+		// These options are only valid for setting a key
+		if a.PrevValue != "" {
+			params.Set("prevValue", a.PrevValue)
+		}
+		form.Add("value", a.Value)
+	}
+
+	// Options which apply to both setting a key and creating a dir
+	if a.PrevIndex != 0 {
+		params.Set("prevIndex", strconv.FormatUint(a.PrevIndex, 10))
+	}
+	if a.PrevExist != PrevIgnore {
+		params.Set("prevExist", string(a.PrevExist))
+	}
+	if a.TTL > 0 {
+		form.Add("ttl", strconv.FormatUint(uint64(a.TTL.Seconds()), 10))
+	}
+
+	if a.Refresh {
+		form.Add("refresh", "true")
+	}
+	if a.NoValueOnSuccess {
+		params.Set("noValueOnSuccess", strconv.FormatBool(a.NoValueOnSuccess))
+	}
+
+	u.RawQuery = params.Encode()
+	body := strings.NewReader(form.Encode())
+
+	req, _ := http.NewRequest(http.MethodPut, u.String(), body)
+	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+
+	return req
+}
+
+type deleteAction struct {
+	Prefix    string
+	Key       string
+	PrevValue string
+	PrevIndex uint64
+	Dir       bool
+	Recursive bool
+}
+
+func (a *deleteAction) HTTPRequest(ep url.URL) *http.Request {
+	u := v2KeysURL(ep, a.Prefix, a.Key)
+
+	params := u.Query()
+	if a.PrevValue != "" {
+		params.Set("prevValue", a.PrevValue)
+	}
+	if a.PrevIndex != 0 {
+		params.Set("prevIndex", strconv.FormatUint(a.PrevIndex, 10))
+	}
+	if a.Dir {
+		params.Set("dir", "true")
+	}
+	if a.Recursive {
+		params.Set("recursive", "true")
+	}
+	u.RawQuery = params.Encode()
+
+	req, _ := http.NewRequest(http.MethodDelete, u.String(), nil)
+	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+
+	return req
+}
+
+type createInOrderAction struct {
+	Prefix string
+	Dir    string
+	Value  string
+	TTL    time.Duration
+}
+
+func (a *createInOrderAction) HTTPRequest(ep url.URL) *http.Request {
+	u := v2KeysURL(ep, a.Prefix, a.Dir)
+
+	form := url.Values{}
+	form.Add("value", a.Value)
+	if a.TTL > 0 {
+		form.Add("ttl", strconv.FormatUint(uint64(a.TTL.Seconds()), 10))
+	}
+	body := strings.NewReader(form.Encode())
+
+	req, _ := http.NewRequest(http.MethodPost, u.String(), body)
+	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+	return req
+}
+
+func unmarshalHTTPResponse(code int, header http.Header, body []byte) (res *Response, err error) {
+	switch code {
+	case http.StatusOK, http.StatusCreated:
+		if len(body) == 0 {
+			return nil, ErrEmptyBody
+		}
+		res, err = unmarshalSuccessfulKeysResponse(header, body)
+	default:
+		err = unmarshalFailedKeysResponse(body)
+	}
+	return res, err
+}
+
+func unmarshalSuccessfulKeysResponse(header http.Header, body []byte) (*Response, error) {
+	var res Response
+	err := kjson.UnmarshalCaseSensitivePreserveInts(body, &res)
+	if err != nil {
+		return nil, ErrInvalidJSON
+	}
+	if header.Get("X-Etcd-Index") != "" {
+		res.Index, err = strconv.ParseUint(header.Get("X-Etcd-Index"), 10, 64)
+		if err != nil {
+			return nil, err
+		}
+	}
+	res.ClusterID = header.Get("X-Etcd-Cluster-ID")
+	return &res, nil
+}
+
+func unmarshalFailedKeysResponse(body []byte) error {
+	var etcdErr Error
+	if err := json.Unmarshal(body, &etcdErr); err != nil {
+		return ErrInvalidJSON
+	}
+	return etcdErr
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/members.go b/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/members.go
new file mode 100644
index 0000000..f53c2db
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/members.go
@@ -0,0 +1,303 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package client
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/url"
+	"path"
+
+	"go.etcd.io/etcd/client/pkg/v3/types"
+)
+
+var (
+	defaultV2MembersPrefix = "/v2/members"
+	defaultLeaderSuffix    = "/leader"
+)
+
+type Member struct {
+	// ID is the unique identifier of this Member.
+	ID string `json:"id"`
+
+	// Name is a human-readable, non-unique identifier of this Member.
+	Name string `json:"name"`
+
+	// PeerURLs represents the HTTP(S) endpoints this Member uses to
+	// participate in etcd's consensus protocol.
+	PeerURLs []string `json:"peerURLs"`
+
+	// ClientURLs represents the HTTP(S) endpoints on which this Member
+	// serves its client-facing APIs.
+	ClientURLs []string `json:"clientURLs"`
+}
+
+type memberCollection []Member
+
+func (c *memberCollection) UnmarshalJSON(data []byte) error {
+	d := struct {
+		Members []Member
+	}{}
+
+	if err := json.Unmarshal(data, &d); err != nil {
+		return err
+	}
+
+	if d.Members == nil {
+		*c = make([]Member, 0)
+		return nil
+	}
+
+	*c = d.Members
+	return nil
+}
+
+type memberCreateOrUpdateRequest struct {
+	PeerURLs types.URLs
+}
+
+func (m *memberCreateOrUpdateRequest) MarshalJSON() ([]byte, error) {
+	s := struct {
+		PeerURLs []string `json:"peerURLs"`
+	}{
+		PeerURLs: make([]string, len(m.PeerURLs)),
+	}
+
+	for i, u := range m.PeerURLs {
+		s.PeerURLs[i] = u.String()
+	}
+
+	return json.Marshal(&s)
+}
+
+// NewMembersAPI constructs a new MembersAPI that uses HTTP to
+// interact with etcd's membership API.
+func NewMembersAPI(c Client) MembersAPI {
+	return &httpMembersAPI{
+		client: c,
+	}
+}
+
+type MembersAPI interface {
+	// List enumerates the current cluster membership.
+	List(ctx context.Context) ([]Member, error)
+
+	// Add instructs etcd to accept a new Member into the cluster.
+	Add(ctx context.Context, peerURL string) (*Member, error)
+
+	// Remove demotes an existing Member out of the cluster.
+	Remove(ctx context.Context, mID string) error
+
+	// Update instructs etcd to update an existing Member in the cluster.
+	Update(ctx context.Context, mID string, peerURLs []string) error
+
+	// Leader gets current leader of the cluster
+	Leader(ctx context.Context) (*Member, error)
+}
+
+type httpMembersAPI struct {
+	client httpClient
+}
+
+func (m *httpMembersAPI) List(ctx context.Context) ([]Member, error) {
+	req := &membersAPIActionList{}
+	resp, body, err := m.client.Do(ctx, req)
+	if err != nil {
+		return nil, err
+	}
+
+	if err := assertStatusCode(resp.StatusCode, http.StatusOK); err != nil {
+		return nil, err
+	}
+
+	var mCollection memberCollection
+	if err := json.Unmarshal(body, &mCollection); err != nil {
+		return nil, err
+	}
+
+	return mCollection, nil
+}
+
+func (m *httpMembersAPI) Add(ctx context.Context, peerURL string) (*Member, error) {
+	urls, err := types.NewURLs([]string{peerURL})
+	if err != nil {
+		return nil, err
+	}
+
+	req := &membersAPIActionAdd{peerURLs: urls}
+	resp, body, err := m.client.Do(ctx, req)
+	if err != nil {
+		return nil, err
+	}
+
+	if err := assertStatusCode(resp.StatusCode, http.StatusCreated, http.StatusConflict); err != nil {
+		return nil, err
+	}
+
+	if resp.StatusCode != http.StatusCreated {
+		var merr membersError
+		if err := json.Unmarshal(body, &merr); err != nil {
+			return nil, err
+		}
+		return nil, merr
+	}
+
+	var memb Member
+	if err := json.Unmarshal(body, &memb); err != nil {
+		return nil, err
+	}
+
+	return &memb, nil
+}
+
+func (m *httpMembersAPI) Update(ctx context.Context, memberID string, peerURLs []string) error {
+	urls, err := types.NewURLs(peerURLs)
+	if err != nil {
+		return err
+	}
+
+	req := &membersAPIActionUpdate{peerURLs: urls, memberID: memberID}
+	resp, body, err := m.client.Do(ctx, req)
+	if err != nil {
+		return err
+	}
+
+	if err := assertStatusCode(resp.StatusCode, http.StatusNoContent, http.StatusNotFound, http.StatusConflict); err != nil {
+		return err
+	}
+
+	if resp.StatusCode != http.StatusNoContent {
+		var merr membersError
+		if err := json.Unmarshal(body, &merr); err != nil {
+			return err
+		}
+		return merr
+	}
+
+	return nil
+}
+
+func (m *httpMembersAPI) Remove(ctx context.Context, memberID string) error {
+	req := &membersAPIActionRemove{memberID: memberID}
+	resp, _, err := m.client.Do(ctx, req)
+	if err != nil {
+		return err
+	}
+
+	return assertStatusCode(resp.StatusCode, http.StatusNoContent, http.StatusGone)
+}
+
+func (m *httpMembersAPI) Leader(ctx context.Context) (*Member, error) {
+	req := &membersAPIActionLeader{}
+	resp, body, err := m.client.Do(ctx, req)
+	if err != nil {
+		return nil, err
+	}
+
+	if err := assertStatusCode(resp.StatusCode, http.StatusOK); err != nil {
+		return nil, err
+	}
+
+	var leader Member
+	if err := json.Unmarshal(body, &leader); err != nil {
+		return nil, err
+	}
+
+	return &leader, nil
+}
+
+type membersAPIActionList struct{}
+
+func (l *membersAPIActionList) HTTPRequest(ep url.URL) *http.Request {
+	u := v2MembersURL(ep)
+	req, _ := http.NewRequest(http.MethodGet, u.String(), nil)
+	return req
+}
+
+type membersAPIActionRemove struct {
+	memberID string
+}
+
+func (d *membersAPIActionRemove) HTTPRequest(ep url.URL) *http.Request {
+	u := v2MembersURL(ep)
+	u.Path = path.Join(u.Path, d.memberID)
+	req, _ := http.NewRequest(http.MethodDelete, u.String(), nil)
+	return req
+}
+
+type membersAPIActionAdd struct {
+	peerURLs types.URLs
+}
+
+func (a *membersAPIActionAdd) HTTPRequest(ep url.URL) *http.Request {
+	u := v2MembersURL(ep)
+	m := memberCreateOrUpdateRequest{PeerURLs: a.peerURLs}
+	b, _ := json.Marshal(&m)
+	req, _ := http.NewRequest(http.MethodPost, u.String(), bytes.NewReader(b))
+	req.Header.Set("Content-Type", "application/json")
+	return req
+}
+
+type membersAPIActionUpdate struct {
+	memberID string
+	peerURLs types.URLs
+}
+
+func (a *membersAPIActionUpdate) HTTPRequest(ep url.URL) *http.Request {
+	u := v2MembersURL(ep)
+	m := memberCreateOrUpdateRequest{PeerURLs: a.peerURLs}
+	u.Path = path.Join(u.Path, a.memberID)
+	b, _ := json.Marshal(&m)
+	req, _ := http.NewRequest(http.MethodPut, u.String(), bytes.NewReader(b))
+	req.Header.Set("Content-Type", "application/json")
+	return req
+}
+
+func assertStatusCode(got int, want ...int) (err error) {
+	for _, w := range want {
+		if w == got {
+			return nil
+		}
+	}
+	return fmt.Errorf("unexpected status code %d", got)
+}
+
+type membersAPIActionLeader struct{}
+
+func (l *membersAPIActionLeader) HTTPRequest(ep url.URL) *http.Request {
+	u := v2MembersURL(ep)
+	u.Path = path.Join(u.Path, defaultLeaderSuffix)
+	req, _ := http.NewRequest(http.MethodGet, u.String(), nil)
+	return req
+}
+
+// v2MembersURL add the necessary path to the provided endpoint
+// to route requests to the default v2 members API.
+func v2MembersURL(ep url.URL) *url.URL {
+	ep.Path = path.Join(ep.Path, defaultV2MembersPrefix)
+	return &ep
+}
+
+type membersError struct {
+	Message string `json:"message"`
+	Code    int    `json:"-"`
+}
+
+func (e membersError) Error() string {
+	return e.Message
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/util.go b/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/util.go
new file mode 100644
index 0000000..76e4132
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/internal/clientv2/util.go
@@ -0,0 +1,48 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package client
+
+import (
+	"errors"
+	"regexp"
+)
+
+var (
+	roleNotFoundRegExp *regexp.Regexp
+	userNotFoundRegExp *regexp.Regexp
+)
+
+func init() {
+	roleNotFoundRegExp = regexp.MustCompile("auth: Role .* does not exist.")
+	userNotFoundRegExp = regexp.MustCompile("auth: User .* does not exist.")
+}
+
+// IsKeyNotFound returns true if the error code is ErrorCodeKeyNotFound.
+func IsKeyNotFound(err error) bool {
+	var cErr Error
+	return errors.As(err, &cErr) && cErr.Code == ErrorCodeKeyNotFound
+}
+
+// IsRoleNotFound returns true if the error means role not found of v2 API.
+func IsRoleNotFound(err error) bool {
+	var ae authError
+	return errors.As(err, &ae) && roleNotFoundRegExp.MatchString(ae.Message)
+}
+
+// IsUserNotFound returns true if the error means user not found of v2 API.
+func IsUserNotFound(err error) bool {
+	var ae authError
+	return errors.As(err, &ae) && userNotFoundRegExp.MatchString(ae.Message)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/lease/doc.go b/vendor/go.etcd.io/etcd/server/v3/lease/doc.go
new file mode 100644
index 0000000..a74eaf7
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/lease/doc.go
@@ -0,0 +1,16 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package lease provides an interface and implementation for time-limited leases over arbitrary resources.
+package lease
diff --git a/vendor/go.etcd.io/etcd/server/v3/lease/lease.go b/vendor/go.etcd.io/etcd/server/v3/lease/lease.go
new file mode 100644
index 0000000..8f194c9
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/lease/lease.go
@@ -0,0 +1,135 @@
+// Copyright 2022 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package lease
+
+import (
+	"math"
+	"sync"
+	"time"
+
+	"go.etcd.io/etcd/server/v3/lease/leasepb"
+	"go.etcd.io/etcd/server/v3/storage/backend"
+	"go.etcd.io/etcd/server/v3/storage/schema"
+)
+
+type Lease struct {
+	ID           LeaseID
+	ttl          int64 // time to live of the lease in seconds
+	remainingTTL int64 // remaining time to live in seconds, if zero valued it is considered unset and the full ttl should be used
+	// expiryMu protects concurrent accesses to expiry
+	expiryMu sync.RWMutex
+	// expiry is time when lease should expire. no expiration when expiry.IsZero() is true
+	expiry time.Time
+
+	// mu protects concurrent accesses to itemSet
+	mu      sync.RWMutex
+	itemSet map[LeaseItem]struct{}
+	revokec chan struct{}
+}
+
+func NewLease(id LeaseID, ttl int64) *Lease {
+	return &Lease{
+		ID:      id,
+		ttl:     ttl,
+		itemSet: make(map[LeaseItem]struct{}),
+		revokec: make(chan struct{}),
+	}
+}
+
+func (l *Lease) expired() bool {
+	return l.Remaining() <= 0
+}
+
+func (l *Lease) persistTo(b backend.Backend) {
+	lpb := leasepb.Lease{ID: int64(l.ID), TTL: l.ttl, RemainingTTL: l.remainingTTL}
+	tx := b.BatchTx()
+	tx.LockInsideApply()
+	defer tx.Unlock()
+	schema.MustUnsafePutLease(tx, &lpb)
+}
+
+// TTL returns the TTL of the Lease.
+func (l *Lease) TTL() int64 {
+	return l.ttl
+}
+
+// SetLeaseItem sets the given lease item, this func is thread-safe
+func (l *Lease) SetLeaseItem(item LeaseItem) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	l.itemSet[item] = struct{}{}
+}
+
+// getRemainingTTL returns the last checkpointed remaining TTL of the lease.
+func (l *Lease) getRemainingTTL() int64 {
+	if l.remainingTTL > 0 {
+		return l.remainingTTL
+	}
+	return l.ttl
+}
+
+// refresh refreshes the expiry of the lease.
+func (l *Lease) refresh(extend time.Duration) {
+	newExpiry := time.Now().Add(extend + time.Duration(l.getRemainingTTL())*time.Second)
+	l.expiryMu.Lock()
+	defer l.expiryMu.Unlock()
+	l.expiry = newExpiry
+}
+
+// forever sets the expiry of lease to be forever.
+func (l *Lease) forever() {
+	l.expiryMu.Lock()
+	defer l.expiryMu.Unlock()
+	l.expiry = forever
+}
+
+// Demoted returns true if the lease's expiry has been reset to forever.
+func (l *Lease) Demoted() bool {
+	l.expiryMu.RLock()
+	defer l.expiryMu.RUnlock()
+	return l.expiry == forever
+}
+
+// Keys returns all the keys attached to the lease.
+func (l *Lease) Keys() []string {
+	l.mu.RLock()
+	keys := make([]string, 0, len(l.itemSet))
+	for k := range l.itemSet {
+		keys = append(keys, k.Key)
+	}
+	l.mu.RUnlock()
+	return keys
+}
+
+// Remaining returns the remaining time of the lease.
+func (l *Lease) Remaining() time.Duration {
+	l.expiryMu.RLock()
+	defer l.expiryMu.RUnlock()
+	if l.expiry.IsZero() {
+		return time.Duration(math.MaxInt64)
+	}
+	return time.Until(l.expiry)
+}
+
+type LeaseItem struct {
+	Key string
+}
+
+// leasesByExpiry implements the sort.Interface.
+type leasesByExpiry []*Lease
+
+func (le leasesByExpiry) Len() int           { return len(le) }
+func (le leasesByExpiry) Less(i, j int) bool { return le[i].Remaining() < le[j].Remaining() }
+func (le leasesByExpiry) Swap(i, j int)      { le[i], le[j] = le[j], le[i] }
diff --git a/vendor/go.etcd.io/etcd/server/v3/lease/lease_queue.go b/vendor/go.etcd.io/etcd/server/v3/lease/lease_queue.go
new file mode 100644
index 0000000..74ffee5
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/lease/lease_queue.go
@@ -0,0 +1,108 @@
+// Copyright 2018 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package lease
+
+import (
+	"container/heap"
+	"time"
+)
+
+// LeaseWithTime contains lease object with a time.
+// For the lessor's lease heap, time identifies the lease expiration time.
+// For the lessor's lease checkpoint heap, the time identifies the next lease checkpoint time.
+type LeaseWithTime struct {
+	id    LeaseID
+	time  time.Time
+	index int
+}
+
+type LeaseQueue []*LeaseWithTime
+
+func (pq LeaseQueue) Len() int { return len(pq) }
+
+func (pq LeaseQueue) Less(i, j int) bool {
+	return pq[i].time.Before(pq[j].time)
+}
+
+func (pq LeaseQueue) Swap(i, j int) {
+	pq[i], pq[j] = pq[j], pq[i]
+	pq[i].index = i
+	pq[j].index = j
+}
+
+func (pq *LeaseQueue) Push(x any) {
+	n := len(*pq)
+	item := x.(*LeaseWithTime)
+	item.index = n
+	*pq = append(*pq, item)
+}
+
+func (pq *LeaseQueue) Pop() any {
+	old := *pq
+	n := len(old)
+	item := old[n-1]
+	item.index = -1 // for safety
+	*pq = old[0 : n-1]
+	return item
+}
+
+// LeaseExpiredNotifier is a queue used to notify lessor to revoke expired lease.
+// Only save one item for a lease, `Register` will update time of the corresponding lease.
+type LeaseExpiredNotifier struct {
+	m     map[LeaseID]*LeaseWithTime
+	queue LeaseQueue
+}
+
+func newLeaseExpiredNotifier() *LeaseExpiredNotifier {
+	return &LeaseExpiredNotifier{
+		m:     make(map[LeaseID]*LeaseWithTime),
+		queue: make(LeaseQueue, 0),
+	}
+}
+
+func (mq *LeaseExpiredNotifier) Init() {
+	heap.Init(&mq.queue)
+	mq.m = make(map[LeaseID]*LeaseWithTime)
+	for _, item := range mq.queue {
+		mq.m[item.id] = item
+	}
+}
+
+func (mq *LeaseExpiredNotifier) RegisterOrUpdate(item *LeaseWithTime) {
+	if old, ok := mq.m[item.id]; ok {
+		old.time = item.time
+		heap.Fix(&mq.queue, old.index)
+	} else {
+		heap.Push(&mq.queue, item)
+		mq.m[item.id] = item
+	}
+}
+
+func (mq *LeaseExpiredNotifier) Unregister() *LeaseWithTime {
+	item := heap.Pop(&mq.queue).(*LeaseWithTime)
+	delete(mq.m, item.id)
+	return item
+}
+
+func (mq *LeaseExpiredNotifier) Peek() *LeaseWithTime {
+	if mq.Len() == 0 {
+		return nil
+	}
+	return mq.queue[0]
+}
+
+func (mq *LeaseExpiredNotifier) Len() int {
+	return len(mq.m)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/lease/leasehttp/doc.go b/vendor/go.etcd.io/etcd/server/v3/lease/leasehttp/doc.go
new file mode 100644
index 0000000..8177a37
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/lease/leasehttp/doc.go
@@ -0,0 +1,16 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package leasehttp serves lease renewals made through HTTP requests.
+package leasehttp
diff --git a/vendor/go.etcd.io/etcd/server/v3/lease/leasehttp/http.go b/vendor/go.etcd.io/etcd/server/v3/lease/leasehttp/http.go
new file mode 100644
index 0000000..d5572c3
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/lease/leasehttp/http.go
@@ -0,0 +1,269 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package leasehttp
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"time"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/pkg/v3/httputil"
+	"go.etcd.io/etcd/server/v3/lease"
+	"go.etcd.io/etcd/server/v3/lease/leasepb"
+)
+
+var (
+	LeasePrefix         = "/leases"
+	LeaseInternalPrefix = "/leases/internal"
+	applyTimeout        = time.Second
+	ErrLeaseHTTPTimeout = errors.New("waiting for node to catch up its applied index has timed out")
+)
+
+// NewHandler returns an http Handler for lease renewals
+func NewHandler(l lease.Lessor, waitch func() <-chan struct{}) http.Handler {
+	return &leaseHandler{l, waitch}
+}
+
+type leaseHandler struct {
+	l      lease.Lessor
+	waitch func() <-chan struct{}
+}
+
+func (h *leaseHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodPost {
+		http.Error(w, "Method Not Allowed", http.StatusMethodNotAllowed)
+		return
+	}
+
+	defer r.Body.Close()
+	b, err := io.ReadAll(r.Body)
+	if err != nil {
+		http.Error(w, "error reading body", http.StatusBadRequest)
+		return
+	}
+
+	var v []byte
+	switch r.URL.Path {
+	case LeasePrefix:
+		lreq := pb.LeaseKeepAliveRequest{}
+		if uerr := lreq.Unmarshal(b); uerr != nil {
+			http.Error(w, "error unmarshalling request", http.StatusBadRequest)
+			return
+		}
+		select {
+		case <-h.waitch():
+		case <-time.After(applyTimeout):
+			http.Error(w, ErrLeaseHTTPTimeout.Error(), http.StatusRequestTimeout)
+			return
+		}
+		ttl, rerr := h.l.Renew(lease.LeaseID(lreq.ID))
+		if rerr != nil {
+			if errors.Is(rerr, lease.ErrLeaseNotFound) {
+				http.Error(w, rerr.Error(), http.StatusNotFound)
+				return
+			}
+
+			http.Error(w, rerr.Error(), http.StatusBadRequest)
+			return
+		}
+		// TODO: fill out ResponseHeader
+		resp := &pb.LeaseKeepAliveResponse{ID: lreq.ID, TTL: ttl}
+		v, err = resp.Marshal()
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+
+	case LeaseInternalPrefix:
+		lreq := leasepb.LeaseInternalRequest{}
+		if lerr := lreq.Unmarshal(b); lerr != nil {
+			http.Error(w, "error unmarshalling request", http.StatusBadRequest)
+			return
+		}
+		select {
+		case <-h.waitch():
+		case <-time.After(applyTimeout):
+			http.Error(w, ErrLeaseHTTPTimeout.Error(), http.StatusRequestTimeout)
+			return
+		}
+
+		// gofail: var beforeLookupWhenForwardLeaseTimeToLive struct{}
+
+		l := h.l.Lookup(lease.LeaseID(lreq.LeaseTimeToLiveRequest.ID))
+		if l == nil {
+			http.Error(w, lease.ErrLeaseNotFound.Error(), http.StatusNotFound)
+			return
+		}
+		// TODO: fill out ResponseHeader
+		resp := &leasepb.LeaseInternalResponse{
+			LeaseTimeToLiveResponse: &pb.LeaseTimeToLiveResponse{
+				Header:     &pb.ResponseHeader{},
+				ID:         lreq.LeaseTimeToLiveRequest.ID,
+				TTL:        int64(l.Remaining().Seconds()),
+				GrantedTTL: l.TTL(),
+			},
+		}
+		if lreq.LeaseTimeToLiveRequest.Keys {
+			ks := l.Keys()
+			kbs := make([][]byte, len(ks))
+			for i := range ks {
+				kbs[i] = []byte(ks[i])
+			}
+			resp.LeaseTimeToLiveResponse.Keys = kbs
+		}
+
+		// The leasor could be demoted if leader changed during lookup.
+		// We should return error to force retry instead of returning
+		// incorrect remaining TTL.
+		if l.Demoted() {
+			http.Error(w, lease.ErrNotPrimary.Error(), http.StatusInternalServerError)
+			return
+		}
+
+		v, err = resp.Marshal()
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+
+	default:
+		http.Error(w, fmt.Sprintf("unknown request path %q", r.URL.Path), http.StatusBadRequest)
+		return
+	}
+
+	w.Header().Set("Content-Type", "application/protobuf")
+	w.Write(v)
+}
+
+// RenewHTTP renews a lease at a given primary server.
+// TODO: Batch request in future?
+func RenewHTTP(ctx context.Context, id lease.LeaseID, url string, rt http.RoundTripper) (int64, error) {
+	// will post lreq protobuf to leader
+	lreq, err := (&pb.LeaseKeepAliveRequest{ID: int64(id)}).Marshal()
+	if err != nil {
+		return -1, err
+	}
+
+	cc := &http.Client{
+		Transport: rt,
+		CheckRedirect: func(req *http.Request, via []*http.Request) error {
+			return http.ErrUseLastResponse
+		},
+	}
+	req, err := http.NewRequest(http.MethodPost, url, bytes.NewReader(lreq))
+	if err != nil {
+		return -1, err
+	}
+	req.Header.Set("Content-Type", "application/protobuf")
+	req.Cancel = ctx.Done()
+
+	resp, err := cc.Do(req)
+	if err != nil {
+		return -1, err
+	}
+	b, err := readResponse(resp)
+	if err != nil {
+		return -1, err
+	}
+
+	if resp.StatusCode == http.StatusRequestTimeout {
+		return -1, ErrLeaseHTTPTimeout
+	}
+
+	if resp.StatusCode == http.StatusNotFound {
+		return -1, lease.ErrLeaseNotFound
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return -1, fmt.Errorf("lease: unknown error(%s)", b)
+	}
+
+	lresp := &pb.LeaseKeepAliveResponse{}
+	if err := lresp.Unmarshal(b); err != nil {
+		return -1, fmt.Errorf(`lease: %w. data = "%s"`, err, b)
+	}
+	if lresp.ID != int64(id) {
+		return -1, fmt.Errorf("lease: renew id mismatch")
+	}
+	return lresp.TTL, nil
+}
+
+// TimeToLiveHTTP retrieves lease information of the given lease ID.
+func TimeToLiveHTTP(ctx context.Context, id lease.LeaseID, keys bool, url string, rt http.RoundTripper) (*leasepb.LeaseInternalResponse, error) {
+	// will post lreq protobuf to leader
+	lreq, err := (&leasepb.LeaseInternalRequest{
+		LeaseTimeToLiveRequest: &pb.LeaseTimeToLiveRequest{
+			ID:   int64(id),
+			Keys: keys,
+		},
+	}).Marshal()
+	if err != nil {
+		return nil, err
+	}
+
+	req, err := http.NewRequest(http.MethodPost, url, bytes.NewReader(lreq))
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set("Content-Type", "application/protobuf")
+
+	req = req.WithContext(ctx)
+
+	cc := &http.Client{
+		Transport: rt,
+		CheckRedirect: func(req *http.Request, via []*http.Request) error {
+			return http.ErrUseLastResponse
+		},
+	}
+	var b []byte
+	// buffer errc channel so that errc don't block inside the go routinue
+	resp, err := cc.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	b, err = readResponse(resp)
+	if err != nil {
+		return nil, err
+	}
+	if resp.StatusCode == http.StatusRequestTimeout {
+		return nil, ErrLeaseHTTPTimeout
+	}
+	if resp.StatusCode == http.StatusNotFound {
+		return nil, lease.ErrLeaseNotFound
+	}
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("lease: unknown error(%s)", string(b))
+	}
+
+	lresp := &leasepb.LeaseInternalResponse{}
+	if err := lresp.Unmarshal(b); err != nil {
+		return nil, fmt.Errorf(`lease: %w. data = "%s"`, err, string(b))
+	}
+	if lresp.LeaseTimeToLiveResponse.ID != int64(id) {
+		return nil, fmt.Errorf("lease: TTL id mismatch")
+	}
+	return lresp, nil
+}
+
+func readResponse(resp *http.Response) (b []byte, err error) {
+	b, err = io.ReadAll(resp.Body)
+	httputil.GracefulClose(resp)
+	return
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/lease/leasepb/lease.pb.go b/vendor/go.etcd.io/etcd/server/v3/lease/leasepb/lease.pb.go
new file mode 100644
index 0000000..ee833d3
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/lease/leasepb/lease.pb.go
@@ -0,0 +1,735 @@
+// Code generated by protoc-gen-gogo. DO NOT EDIT.
+// source: lease.proto
+
+package leasepb
+
+import (
+	fmt "fmt"
+	io "io"
+	math "math"
+	math_bits "math/bits"
+
+	_ "github.com/gogo/protobuf/gogoproto"
+	proto "github.com/golang/protobuf/proto"
+	etcdserverpb "go.etcd.io/etcd/api/v3/etcdserverpb"
+)
+
+// Reference imports to suppress errors if they are not otherwise used.
+var _ = proto.Marshal
+var _ = fmt.Errorf
+var _ = math.Inf
+
+// This is a compile-time assertion to ensure that this generated file
+// is compatible with the proto package it is being compiled against.
+// A compilation error at this line likely means your copy of the
+// proto package needs to be updated.
+const _ = proto.ProtoPackageIsVersion3 // please upgrade the proto package
+
+type Lease struct {
+	ID                   int64    `protobuf:"varint,1,opt,name=ID,proto3" json:"ID,omitempty"`
+	TTL                  int64    `protobuf:"varint,2,opt,name=TTL,proto3" json:"TTL,omitempty"`
+	RemainingTTL         int64    `protobuf:"varint,3,opt,name=RemainingTTL,proto3" json:"RemainingTTL,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
+}
+
+func (m *Lease) Reset()         { *m = Lease{} }
+func (m *Lease) String() string { return proto.CompactTextString(m) }
+func (*Lease) ProtoMessage()    {}
+func (*Lease) Descriptor() ([]byte, []int) {
+	return fileDescriptor_3dd57e402472b33a, []int{0}
+}
+func (m *Lease) XXX_Unmarshal(b []byte) error {
+	return m.Unmarshal(b)
+}
+func (m *Lease) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	if deterministic {
+		return xxx_messageInfo_Lease.Marshal(b, m, deterministic)
+	} else {
+		b = b[:cap(b)]
+		n, err := m.MarshalToSizedBuffer(b)
+		if err != nil {
+			return nil, err
+		}
+		return b[:n], nil
+	}
+}
+func (m *Lease) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_Lease.Merge(m, src)
+}
+func (m *Lease) XXX_Size() int {
+	return m.Size()
+}
+func (m *Lease) XXX_DiscardUnknown() {
+	xxx_messageInfo_Lease.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_Lease proto.InternalMessageInfo
+
+type LeaseInternalRequest struct {
+	LeaseTimeToLiveRequest *etcdserverpb.LeaseTimeToLiveRequest `protobuf:"bytes,1,opt,name=LeaseTimeToLiveRequest,proto3" json:"LeaseTimeToLiveRequest,omitempty"`
+	XXX_NoUnkeyedLiteral   struct{}                             `json:"-"`
+	XXX_unrecognized       []byte                               `json:"-"`
+	XXX_sizecache          int32                                `json:"-"`
+}
+
+func (m *LeaseInternalRequest) Reset()         { *m = LeaseInternalRequest{} }
+func (m *LeaseInternalRequest) String() string { return proto.CompactTextString(m) }
+func (*LeaseInternalRequest) ProtoMessage()    {}
+func (*LeaseInternalRequest) Descriptor() ([]byte, []int) {
+	return fileDescriptor_3dd57e402472b33a, []int{1}
+}
+func (m *LeaseInternalRequest) XXX_Unmarshal(b []byte) error {
+	return m.Unmarshal(b)
+}
+func (m *LeaseInternalRequest) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	if deterministic {
+		return xxx_messageInfo_LeaseInternalRequest.Marshal(b, m, deterministic)
+	} else {
+		b = b[:cap(b)]
+		n, err := m.MarshalToSizedBuffer(b)
+		if err != nil {
+			return nil, err
+		}
+		return b[:n], nil
+	}
+}
+func (m *LeaseInternalRequest) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_LeaseInternalRequest.Merge(m, src)
+}
+func (m *LeaseInternalRequest) XXX_Size() int {
+	return m.Size()
+}
+func (m *LeaseInternalRequest) XXX_DiscardUnknown() {
+	xxx_messageInfo_LeaseInternalRequest.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_LeaseInternalRequest proto.InternalMessageInfo
+
+type LeaseInternalResponse struct {
+	LeaseTimeToLiveResponse *etcdserverpb.LeaseTimeToLiveResponse `protobuf:"bytes,1,opt,name=LeaseTimeToLiveResponse,proto3" json:"LeaseTimeToLiveResponse,omitempty"`
+	XXX_NoUnkeyedLiteral    struct{}                              `json:"-"`
+	XXX_unrecognized        []byte                                `json:"-"`
+	XXX_sizecache           int32                                 `json:"-"`
+}
+
+func (m *LeaseInternalResponse) Reset()         { *m = LeaseInternalResponse{} }
+func (m *LeaseInternalResponse) String() string { return proto.CompactTextString(m) }
+func (*LeaseInternalResponse) ProtoMessage()    {}
+func (*LeaseInternalResponse) Descriptor() ([]byte, []int) {
+	return fileDescriptor_3dd57e402472b33a, []int{2}
+}
+func (m *LeaseInternalResponse) XXX_Unmarshal(b []byte) error {
+	return m.Unmarshal(b)
+}
+func (m *LeaseInternalResponse) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	if deterministic {
+		return xxx_messageInfo_LeaseInternalResponse.Marshal(b, m, deterministic)
+	} else {
+		b = b[:cap(b)]
+		n, err := m.MarshalToSizedBuffer(b)
+		if err != nil {
+			return nil, err
+		}
+		return b[:n], nil
+	}
+}
+func (m *LeaseInternalResponse) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_LeaseInternalResponse.Merge(m, src)
+}
+func (m *LeaseInternalResponse) XXX_Size() int {
+	return m.Size()
+}
+func (m *LeaseInternalResponse) XXX_DiscardUnknown() {
+	xxx_messageInfo_LeaseInternalResponse.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_LeaseInternalResponse proto.InternalMessageInfo
+
+func init() {
+	proto.RegisterType((*Lease)(nil), "leasepb.Lease")
+	proto.RegisterType((*LeaseInternalRequest)(nil), "leasepb.LeaseInternalRequest")
+	proto.RegisterType((*LeaseInternalResponse)(nil), "leasepb.LeaseInternalResponse")
+}
+
+func init() { proto.RegisterFile("lease.proto", fileDescriptor_3dd57e402472b33a) }
+
+var fileDescriptor_3dd57e402472b33a = []byte{
+	// 283 bytes of a gzipped FileDescriptorProto
+	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0xe2, 0xe2, 0xce, 0x49, 0x4d, 0x2c,
+	0x4e, 0xd5, 0x2b, 0x28, 0xca, 0x2f, 0xc9, 0x17, 0x62, 0x07, 0x73, 0x0a, 0x92, 0xa4, 0x44, 0xd2,
+	0xf3, 0xd3, 0xf3, 0xc1, 0x62, 0xfa, 0x20, 0x16, 0x44, 0x5a, 0x4a, 0x3e, 0xb5, 0x24, 0x39, 0x45,
+	0x3f, 0xb1, 0x20, 0x53, 0x1f, 0xc4, 0x28, 0x4e, 0x2d, 0x2a, 0x4b, 0x2d, 0x2a, 0x48, 0xd2, 0x2f,
+	0x2a, 0x48, 0x86, 0x28, 0x50, 0xf2, 0xe5, 0x62, 0xf5, 0x01, 0x99, 0x20, 0xc4, 0xc7, 0xc5, 0xe4,
+	0xe9, 0x22, 0xc1, 0xa8, 0xc0, 0xa8, 0xc1, 0x1c, 0xc4, 0xe4, 0xe9, 0x22, 0x24, 0xc0, 0xc5, 0x1c,
+	0x12, 0xe2, 0x23, 0xc1, 0x04, 0x16, 0x00, 0x31, 0x85, 0x94, 0xb8, 0x78, 0x82, 0x52, 0x73, 0x13,
+	0x33, 0xf3, 0x32, 0xf3, 0xd2, 0x41, 0x52, 0xcc, 0x60, 0x29, 0x14, 0x31, 0xa5, 0x12, 0x2e, 0x11,
+	0xb0, 0x71, 0x9e, 0x79, 0x25, 0xa9, 0x45, 0x79, 0x89, 0x39, 0x41, 0xa9, 0x85, 0xa5, 0xa9, 0xc5,
+	0x25, 0x42, 0x31, 0x5c, 0x62, 0x60, 0xf1, 0x90, 0xcc, 0xdc, 0xd4, 0x90, 0x7c, 0x9f, 0xcc, 0xb2,
+	0x54, 0xa8, 0x0c, 0xd8, 0x46, 0x6e, 0x23, 0x15, 0x3d, 0x64, 0xf7, 0xe9, 0x61, 0x57, 0x1b, 0x84,
+	0xc3, 0x0c, 0xa5, 0x0a, 0x2e, 0x51, 0x34, 0x5b, 0x8b, 0x0b, 0xf2, 0xf3, 0x8a, 0x53, 0x85, 0xe2,
+	0xb9, 0xc4, 0x31, 0xb4, 0x40, 0xa4, 0xa0, 0xf6, 0xaa, 0x12, 0xb0, 0x17, 0xa2, 0x38, 0x08, 0x97,
+	0x29, 0x4e, 0x9e, 0x27, 0x1e, 0xca, 0x31, 0x5c, 0x78, 0x28, 0xc7, 0x70, 0xe2, 0x91, 0x1c, 0xe3,
+	0x85, 0x47, 0x72, 0x8c, 0x0f, 0x1e, 0xc9, 0x31, 0xce, 0x78, 0x2c, 0xc7, 0x10, 0xa5, 0x9f, 0x9e,
+	0x0f, 0x36, 0x5b, 0x2f, 0x33, 0x1f, 0x1c, 0xf6, 0xfa, 0x10, 0x4b, 0xf4, 0xcb, 0x8c, 0xf5, 0xc1,
+	0x51, 0xa6, 0x0f, 0x8d, 0x38, 0x6b, 0x28, 0x9d, 0xc4, 0x06, 0x8e, 0x10, 0x63, 0x40, 0x00, 0x00,
+	0x00, 0xff, 0xff, 0x0e, 0x16, 0x3b, 0xc4, 0xdf, 0x01, 0x00, 0x00,
+}
+
+func (m *Lease) Marshal() (dAtA []byte, err error) {
+	size := m.Size()
+	dAtA = make([]byte, size)
+	n, err := m.MarshalToSizedBuffer(dAtA[:size])
+	if err != nil {
+		return nil, err
+	}
+	return dAtA[:n], nil
+}
+
+func (m *Lease) MarshalTo(dAtA []byte) (int, error) {
+	size := m.Size()
+	return m.MarshalToSizedBuffer(dAtA[:size])
+}
+
+func (m *Lease) MarshalToSizedBuffer(dAtA []byte) (int, error) {
+	i := len(dAtA)
+	_ = i
+	var l int
+	_ = l
+	if m.XXX_unrecognized != nil {
+		i -= len(m.XXX_unrecognized)
+		copy(dAtA[i:], m.XXX_unrecognized)
+	}
+	if m.RemainingTTL != 0 {
+		i = encodeVarintLease(dAtA, i, uint64(m.RemainingTTL))
+		i--
+		dAtA[i] = 0x18
+	}
+	if m.TTL != 0 {
+		i = encodeVarintLease(dAtA, i, uint64(m.TTL))
+		i--
+		dAtA[i] = 0x10
+	}
+	if m.ID != 0 {
+		i = encodeVarintLease(dAtA, i, uint64(m.ID))
+		i--
+		dAtA[i] = 0x8
+	}
+	return len(dAtA) - i, nil
+}
+
+func (m *LeaseInternalRequest) Marshal() (dAtA []byte, err error) {
+	size := m.Size()
+	dAtA = make([]byte, size)
+	n, err := m.MarshalToSizedBuffer(dAtA[:size])
+	if err != nil {
+		return nil, err
+	}
+	return dAtA[:n], nil
+}
+
+func (m *LeaseInternalRequest) MarshalTo(dAtA []byte) (int, error) {
+	size := m.Size()
+	return m.MarshalToSizedBuffer(dAtA[:size])
+}
+
+func (m *LeaseInternalRequest) MarshalToSizedBuffer(dAtA []byte) (int, error) {
+	i := len(dAtA)
+	_ = i
+	var l int
+	_ = l
+	if m.XXX_unrecognized != nil {
+		i -= len(m.XXX_unrecognized)
+		copy(dAtA[i:], m.XXX_unrecognized)
+	}
+	if m.LeaseTimeToLiveRequest != nil {
+		{
+			size, err := m.LeaseTimeToLiveRequest.MarshalToSizedBuffer(dAtA[:i])
+			if err != nil {
+				return 0, err
+			}
+			i -= size
+			i = encodeVarintLease(dAtA, i, uint64(size))
+		}
+		i--
+		dAtA[i] = 0xa
+	}
+	return len(dAtA) - i, nil
+}
+
+func (m *LeaseInternalResponse) Marshal() (dAtA []byte, err error) {
+	size := m.Size()
+	dAtA = make([]byte, size)
+	n, err := m.MarshalToSizedBuffer(dAtA[:size])
+	if err != nil {
+		return nil, err
+	}
+	return dAtA[:n], nil
+}
+
+func (m *LeaseInternalResponse) MarshalTo(dAtA []byte) (int, error) {
+	size := m.Size()
+	return m.MarshalToSizedBuffer(dAtA[:size])
+}
+
+func (m *LeaseInternalResponse) MarshalToSizedBuffer(dAtA []byte) (int, error) {
+	i := len(dAtA)
+	_ = i
+	var l int
+	_ = l
+	if m.XXX_unrecognized != nil {
+		i -= len(m.XXX_unrecognized)
+		copy(dAtA[i:], m.XXX_unrecognized)
+	}
+	if m.LeaseTimeToLiveResponse != nil {
+		{
+			size, err := m.LeaseTimeToLiveResponse.MarshalToSizedBuffer(dAtA[:i])
+			if err != nil {
+				return 0, err
+			}
+			i -= size
+			i = encodeVarintLease(dAtA, i, uint64(size))
+		}
+		i--
+		dAtA[i] = 0xa
+	}
+	return len(dAtA) - i, nil
+}
+
+func encodeVarintLease(dAtA []byte, offset int, v uint64) int {
+	offset -= sovLease(v)
+	base := offset
+	for v >= 1<<7 {
+		dAtA[offset] = uint8(v&0x7f | 0x80)
+		v >>= 7
+		offset++
+	}
+	dAtA[offset] = uint8(v)
+	return base
+}
+func (m *Lease) Size() (n int) {
+	if m == nil {
+		return 0
+	}
+	var l int
+	_ = l
+	if m.ID != 0 {
+		n += 1 + sovLease(uint64(m.ID))
+	}
+	if m.TTL != 0 {
+		n += 1 + sovLease(uint64(m.TTL))
+	}
+	if m.RemainingTTL != 0 {
+		n += 1 + sovLease(uint64(m.RemainingTTL))
+	}
+	if m.XXX_unrecognized != nil {
+		n += len(m.XXX_unrecognized)
+	}
+	return n
+}
+
+func (m *LeaseInternalRequest) Size() (n int) {
+	if m == nil {
+		return 0
+	}
+	var l int
+	_ = l
+	if m.LeaseTimeToLiveRequest != nil {
+		l = m.LeaseTimeToLiveRequest.Size()
+		n += 1 + l + sovLease(uint64(l))
+	}
+	if m.XXX_unrecognized != nil {
+		n += len(m.XXX_unrecognized)
+	}
+	return n
+}
+
+func (m *LeaseInternalResponse) Size() (n int) {
+	if m == nil {
+		return 0
+	}
+	var l int
+	_ = l
+	if m.LeaseTimeToLiveResponse != nil {
+		l = m.LeaseTimeToLiveResponse.Size()
+		n += 1 + l + sovLease(uint64(l))
+	}
+	if m.XXX_unrecognized != nil {
+		n += len(m.XXX_unrecognized)
+	}
+	return n
+}
+
+func sovLease(x uint64) (n int) {
+	return (math_bits.Len64(x|1) + 6) / 7
+}
+func sozLease(x uint64) (n int) {
+	return sovLease(uint64((x << 1) ^ uint64((int64(x) >> 63))))
+}
+func (m *Lease) Unmarshal(dAtA []byte) error {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		preIndex := iNdEx
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return ErrIntOverflowLease
+			}
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= uint64(b&0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		if wireType == 4 {
+			return fmt.Errorf("proto: Lease: wiretype end group for non-group")
+		}
+		if fieldNum <= 0 {
+			return fmt.Errorf("proto: Lease: illegal tag %d (wire type %d)", fieldNum, wire)
+		}
+		switch fieldNum {
+		case 1:
+			if wireType != 0 {
+				return fmt.Errorf("proto: wrong wireType = %d for field ID", wireType)
+			}
+			m.ID = 0
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowLease
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				m.ID |= int64(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+		case 2:
+			if wireType != 0 {
+				return fmt.Errorf("proto: wrong wireType = %d for field TTL", wireType)
+			}
+			m.TTL = 0
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowLease
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				m.TTL |= int64(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+		case 3:
+			if wireType != 0 {
+				return fmt.Errorf("proto: wrong wireType = %d for field RemainingTTL", wireType)
+			}
+			m.RemainingTTL = 0
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowLease
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				m.RemainingTTL |= int64(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+		default:
+			iNdEx = preIndex
+			skippy, err := skipLease(dAtA[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
+				return ErrInvalidLengthLease
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.XXX_unrecognized = append(m.XXX_unrecognized, dAtA[iNdEx:iNdEx+skippy]...)
+			iNdEx += skippy
+		}
+	}
+
+	if iNdEx > l {
+		return io.ErrUnexpectedEOF
+	}
+	return nil
+}
+func (m *LeaseInternalRequest) Unmarshal(dAtA []byte) error {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		preIndex := iNdEx
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return ErrIntOverflowLease
+			}
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= uint64(b&0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		if wireType == 4 {
+			return fmt.Errorf("proto: LeaseInternalRequest: wiretype end group for non-group")
+		}
+		if fieldNum <= 0 {
+			return fmt.Errorf("proto: LeaseInternalRequest: illegal tag %d (wire type %d)", fieldNum, wire)
+		}
+		switch fieldNum {
+		case 1:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field LeaseTimeToLiveRequest", wireType)
+			}
+			var msglen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowLease
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				msglen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if msglen < 0 {
+				return ErrInvalidLengthLease
+			}
+			postIndex := iNdEx + msglen
+			if postIndex < 0 {
+				return ErrInvalidLengthLease
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			if m.LeaseTimeToLiveRequest == nil {
+				m.LeaseTimeToLiveRequest = &etcdserverpb.LeaseTimeToLiveRequest{}
+			}
+			if err := m.LeaseTimeToLiveRequest.Unmarshal(dAtA[iNdEx:postIndex]); err != nil {
+				return err
+			}
+			iNdEx = postIndex
+		default:
+			iNdEx = preIndex
+			skippy, err := skipLease(dAtA[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
+				return ErrInvalidLengthLease
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.XXX_unrecognized = append(m.XXX_unrecognized, dAtA[iNdEx:iNdEx+skippy]...)
+			iNdEx += skippy
+		}
+	}
+
+	if iNdEx > l {
+		return io.ErrUnexpectedEOF
+	}
+	return nil
+}
+func (m *LeaseInternalResponse) Unmarshal(dAtA []byte) error {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		preIndex := iNdEx
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return ErrIntOverflowLease
+			}
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= uint64(b&0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		if wireType == 4 {
+			return fmt.Errorf("proto: LeaseInternalResponse: wiretype end group for non-group")
+		}
+		if fieldNum <= 0 {
+			return fmt.Errorf("proto: LeaseInternalResponse: illegal tag %d (wire type %d)", fieldNum, wire)
+		}
+		switch fieldNum {
+		case 1:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field LeaseTimeToLiveResponse", wireType)
+			}
+			var msglen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowLease
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				msglen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if msglen < 0 {
+				return ErrInvalidLengthLease
+			}
+			postIndex := iNdEx + msglen
+			if postIndex < 0 {
+				return ErrInvalidLengthLease
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			if m.LeaseTimeToLiveResponse == nil {
+				m.LeaseTimeToLiveResponse = &etcdserverpb.LeaseTimeToLiveResponse{}
+			}
+			if err := m.LeaseTimeToLiveResponse.Unmarshal(dAtA[iNdEx:postIndex]); err != nil {
+				return err
+			}
+			iNdEx = postIndex
+		default:
+			iNdEx = preIndex
+			skippy, err := skipLease(dAtA[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
+				return ErrInvalidLengthLease
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.XXX_unrecognized = append(m.XXX_unrecognized, dAtA[iNdEx:iNdEx+skippy]...)
+			iNdEx += skippy
+		}
+	}
+
+	if iNdEx > l {
+		return io.ErrUnexpectedEOF
+	}
+	return nil
+}
+func skipLease(dAtA []byte) (n int, err error) {
+	l := len(dAtA)
+	iNdEx := 0
+	depth := 0
+	for iNdEx < l {
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return 0, ErrIntOverflowLease
+			}
+			if iNdEx >= l {
+				return 0, io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= (uint64(b) & 0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		wireType := int(wire & 0x7)
+		switch wireType {
+		case 0:
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return 0, ErrIntOverflowLease
+				}
+				if iNdEx >= l {
+					return 0, io.ErrUnexpectedEOF
+				}
+				iNdEx++
+				if dAtA[iNdEx-1] < 0x80 {
+					break
+				}
+			}
+		case 1:
+			iNdEx += 8
+		case 2:
+			var length int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return 0, ErrIntOverflowLease
+				}
+				if iNdEx >= l {
+					return 0, io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				length |= (int(b) & 0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if length < 0 {
+				return 0, ErrInvalidLengthLease
+			}
+			iNdEx += length
+		case 3:
+			depth++
+		case 4:
+			if depth == 0 {
+				return 0, ErrUnexpectedEndOfGroupLease
+			}
+			depth--
+		case 5:
+			iNdEx += 4
+		default:
+			return 0, fmt.Errorf("proto: illegal wireType %d", wireType)
+		}
+		if iNdEx < 0 {
+			return 0, ErrInvalidLengthLease
+		}
+		if depth == 0 {
+			return iNdEx, nil
+		}
+	}
+	return 0, io.ErrUnexpectedEOF
+}
+
+var (
+	ErrInvalidLengthLease        = fmt.Errorf("proto: negative length found during unmarshaling")
+	ErrIntOverflowLease          = fmt.Errorf("proto: integer overflow")
+	ErrUnexpectedEndOfGroupLease = fmt.Errorf("proto: unexpected end of group")
+)
diff --git a/vendor/go.etcd.io/etcd/server/v3/lease/leasepb/lease.proto b/vendor/go.etcd.io/etcd/server/v3/lease/leasepb/lease.proto
new file mode 100644
index 0000000..d631797
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/lease/leasepb/lease.proto
@@ -0,0 +1,27 @@
+syntax = "proto3";
+package leasepb;
+
+import "gogoproto/gogo.proto";
+import "etcd/api/etcdserverpb/rpc.proto";
+
+option go_package = "go.etcd.io/etcd/server/v3/lease/leasepb;leasepb";
+
+option (gogoproto.marshaler_all) = true;
+option (gogoproto.sizer_all) = true;
+option (gogoproto.unmarshaler_all) = true;
+option (gogoproto.goproto_getters_all) = false;
+option (gogoproto.goproto_enum_prefix_all) = false;
+
+message Lease {
+  int64 ID = 1;
+  int64 TTL = 2;
+  int64 RemainingTTL = 3;
+}
+
+message LeaseInternalRequest {
+  etcdserverpb.LeaseTimeToLiveRequest LeaseTimeToLiveRequest = 1;
+}
+
+message LeaseInternalResponse {
+  etcdserverpb.LeaseTimeToLiveResponse LeaseTimeToLiveResponse = 1;
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/lease/lessor.go b/vendor/go.etcd.io/etcd/server/v3/lease/lessor.go
new file mode 100644
index 0000000..b13974c
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/lease/lessor.go
@@ -0,0 +1,887 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package lease
+
+import (
+	"container/heap"
+	"context"
+	"errors"
+	"math"
+	"sort"
+	"sync"
+	"time"
+
+	"github.com/coreos/go-semver/semver"
+	"go.uber.org/zap"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/api/v3/version"
+	"go.etcd.io/etcd/server/v3/lease/leasepb"
+	"go.etcd.io/etcd/server/v3/storage/backend"
+	"go.etcd.io/etcd/server/v3/storage/schema"
+)
+
+// NoLease is a special LeaseID representing the absence of a lease.
+const NoLease = LeaseID(0)
+
+// MaxLeaseTTL is the maximum lease TTL value
+const MaxLeaseTTL = 9000000000
+
+var (
+	forever = time.Time{}
+
+	// default number of leases to revoke per second; configurable for tests
+	defaultLeaseRevokeRate = 1000
+
+	// maximum number of lease checkpoints recorded to the consensus log per second; configurable for tests
+	leaseCheckpointRate = 1000
+
+	// the default interval of lease checkpoint
+	defaultLeaseCheckpointInterval = 5 * time.Minute
+
+	// maximum number of lease checkpoints to batch into a single consensus log entry
+	maxLeaseCheckpointBatchSize = 1000
+
+	// the default interval to check if the expired lease is revoked
+	defaultExpiredleaseRetryInterval = 3 * time.Second
+
+	ErrNotPrimary       = errors.New("not a primary lessor")
+	ErrLeaseNotFound    = errors.New("lease not found")
+	ErrLeaseExists      = errors.New("lease already exists")
+	ErrLeaseTTLTooLarge = errors.New("too large lease TTL")
+)
+
+// TxnDelete is a TxnWrite that only permits deletes. Defined here
+// to avoid circular dependency with mvcc.
+type TxnDelete interface {
+	DeleteRange(key, end []byte) (n, rev int64)
+	End()
+}
+
+// RangeDeleter is a TxnDelete constructor.
+type RangeDeleter func() TxnDelete
+
+// Checkpointer permits checkpointing of lease remaining TTLs to the consensus log. Defined here to
+// avoid circular dependency with mvcc.
+type Checkpointer func(ctx context.Context, lc *pb.LeaseCheckpointRequest) error
+
+type LeaseID int64
+
+// Lessor owns leases. It can grant, revoke, renew and modify leases for lessee.
+type Lessor interface {
+	// SetRangeDeleter lets the lessor create TxnDeletes to the store.
+	// Lessor deletes the items in the revoked or expired lease by creating
+	// new TxnDeletes.
+	SetRangeDeleter(rd RangeDeleter)
+
+	SetCheckpointer(cp Checkpointer)
+
+	// Grant grants a lease that expires at least after TTL seconds.
+	Grant(id LeaseID, ttl int64) (*Lease, error)
+	// Revoke revokes a lease with given ID. The item attached to the
+	// given lease will be removed. If the ID does not exist, an error
+	// will be returned.
+	Revoke(id LeaseID) error
+
+	// Checkpoint applies the remainingTTL of a lease. The remainingTTL is used in Promote to set
+	// the expiry of leases to less than the full TTL when possible.
+	Checkpoint(id LeaseID, remainingTTL int64) error
+
+	// Attach attaches given leaseItem to the lease with given LeaseID.
+	// If the lease does not exist, an error will be returned.
+	Attach(id LeaseID, items []LeaseItem) error
+
+	// GetLease returns LeaseID for given item.
+	// If no lease found, NoLease value will be returned.
+	GetLease(item LeaseItem) LeaseID
+
+	// Detach detaches given leaseItem from the lease with given LeaseID.
+	// If the lease does not exist, an error will be returned.
+	Detach(id LeaseID, items []LeaseItem) error
+
+	// Promote promotes the lessor to be the primary lessor. Primary lessor manages
+	// the expiration and renew of leases.
+	// Newly promoted lessor renew the TTL of all lease to extend + previous TTL.
+	Promote(extend time.Duration)
+
+	// Demote demotes the lessor from being the primary lessor.
+	Demote()
+
+	// Renew renews a lease with given ID. It returns the renewed TTL. If the ID does not exist,
+	// an error will be returned.
+	Renew(id LeaseID) (int64, error)
+
+	// Lookup gives the lease at a given lease id, if any
+	Lookup(id LeaseID) *Lease
+
+	// Leases lists all leases.
+	Leases() []*Lease
+
+	// ExpiredLeasesC returns a chan that is used to receive expired leases.
+	ExpiredLeasesC() <-chan []*Lease
+
+	// Recover recovers the lessor state from the given backend and RangeDeleter.
+	Recover(b backend.Backend, rd RangeDeleter)
+
+	// Stop stops the lessor for managing leases. The behavior of calling Stop multiple
+	// times is undefined.
+	Stop()
+}
+
+// lessor implements Lessor interface.
+// TODO: use clockwork for testability.
+type lessor struct {
+	mu sync.RWMutex
+
+	// demotec is set when the lessor is the primary.
+	// demotec will be closed if the lessor is demoted.
+	demotec chan struct{}
+
+	leaseMap             map[LeaseID]*Lease
+	leaseExpiredNotifier *LeaseExpiredNotifier
+	leaseCheckpointHeap  LeaseQueue
+	itemMap              map[LeaseItem]LeaseID
+
+	// When a lease expires, the lessor will delete the
+	// leased range (or key) by the RangeDeleter.
+	rd RangeDeleter
+
+	// When a lease's deadline should be persisted to preserve the remaining TTL across leader
+	// elections and restarts, the lessor will checkpoint the lease by the Checkpointer.
+	cp Checkpointer
+
+	// backend to persist leases. We only persist lease ID and expiry for now.
+	// The leased items can be recovered by iterating all the keys in kv.
+	b backend.Backend
+
+	// minLeaseTTL is the minimum lease TTL that can be granted for a lease. Any
+	// requests for shorter TTLs are extended to the minimum TTL.
+	minLeaseTTL int64
+
+	// maximum number of leases to revoke per second
+	leaseRevokeRate int
+
+	expiredC chan []*Lease
+	// stopC is a channel whose closure indicates that the lessor should be stopped.
+	stopC chan struct{}
+	// doneC is a channel whose closure indicates that the lessor is stopped.
+	doneC chan struct{}
+
+	lg *zap.Logger
+
+	// Wait duration between lease checkpoints.
+	checkpointInterval time.Duration
+	// the interval to check if the expired lease is revoked
+	expiredLeaseRetryInterval time.Duration
+	// whether lessor should always persist remaining TTL (always enabled in v3.6).
+	checkpointPersist bool
+	// cluster is used to adapt lessor logic based on cluster version
+	cluster cluster
+}
+
+type cluster interface {
+	// Version is the cluster-wide minimum major.minor version.
+	Version() *semver.Version
+}
+
+type LessorConfig struct {
+	MinLeaseTTL                int64
+	CheckpointInterval         time.Duration
+	ExpiredLeasesRetryInterval time.Duration
+	CheckpointPersist          bool
+
+	leaseRevokeRate int
+}
+
+func NewLessor(lg *zap.Logger, b backend.Backend, cluster cluster, cfg LessorConfig) Lessor {
+	return newLessor(lg, b, cluster, cfg)
+}
+
+func newLessor(lg *zap.Logger, b backend.Backend, cluster cluster, cfg LessorConfig) *lessor {
+	checkpointInterval := cfg.CheckpointInterval
+	expiredLeaseRetryInterval := cfg.ExpiredLeasesRetryInterval
+	leaseRevokeRate := cfg.leaseRevokeRate
+	if checkpointInterval == 0 {
+		checkpointInterval = defaultLeaseCheckpointInterval
+	}
+	if expiredLeaseRetryInterval == 0 {
+		expiredLeaseRetryInterval = defaultExpiredleaseRetryInterval
+	}
+	if leaseRevokeRate == 0 {
+		leaseRevokeRate = defaultLeaseRevokeRate
+	}
+	l := &lessor{
+		leaseMap:                  make(map[LeaseID]*Lease),
+		itemMap:                   make(map[LeaseItem]LeaseID),
+		leaseExpiredNotifier:      newLeaseExpiredNotifier(),
+		leaseCheckpointHeap:       make(LeaseQueue, 0),
+		b:                         b,
+		minLeaseTTL:               cfg.MinLeaseTTL,
+		leaseRevokeRate:           leaseRevokeRate,
+		checkpointInterval:        checkpointInterval,
+		expiredLeaseRetryInterval: expiredLeaseRetryInterval,
+		checkpointPersist:         cfg.CheckpointPersist,
+		// expiredC is a small buffered chan to avoid unnecessary blocking.
+		expiredC: make(chan []*Lease, 16),
+		stopC:    make(chan struct{}),
+		doneC:    make(chan struct{}),
+		lg:       lg,
+		cluster:  cluster,
+	}
+	l.initAndRecover()
+
+	go l.runLoop()
+
+	return l
+}
+
+// isPrimary indicates if this lessor is the primary lessor. The primary
+// lessor manages lease expiration and renew.
+//
+// in etcd, raft leader is the primary. Thus there might be two primary
+// leaders at the same time (raft allows concurrent leader but with different term)
+// for at most a leader election timeout.
+// The old primary leader cannot affect the correctness since its proposal has a
+// smaller term and will not be committed.
+//
+// TODO: raft follower do not forward lease management proposals. There might be a
+// very small window (within second normally which depends on go scheduling) that
+// a raft follow is the primary between the raft leader demotion and lessor demotion.
+// Usually this should not be a problem. Lease should not be that sensitive to timing.
+func (le *lessor) isPrimary() bool {
+	return le.demotec != nil
+}
+
+func (le *lessor) SetRangeDeleter(rd RangeDeleter) {
+	le.mu.Lock()
+	defer le.mu.Unlock()
+
+	le.rd = rd
+}
+
+func (le *lessor) SetCheckpointer(cp Checkpointer) {
+	le.mu.Lock()
+	defer le.mu.Unlock()
+
+	le.cp = cp
+}
+
+func (le *lessor) Grant(id LeaseID, ttl int64) (*Lease, error) {
+	if id == NoLease {
+		return nil, ErrLeaseNotFound
+	}
+
+	if ttl > MaxLeaseTTL {
+		return nil, ErrLeaseTTLTooLarge
+	}
+
+	// TODO: when lessor is under high load, it should give out lease
+	// with longer TTL to reduce renew load.
+	l := NewLease(id, ttl)
+
+	le.mu.Lock()
+	defer le.mu.Unlock()
+
+	if _, ok := le.leaseMap[id]; ok {
+		return nil, ErrLeaseExists
+	}
+
+	if l.ttl < le.minLeaseTTL {
+		l.ttl = le.minLeaseTTL
+	}
+
+	if le.isPrimary() {
+		l.refresh(0)
+	} else {
+		l.forever()
+	}
+
+	le.leaseMap[id] = l
+	l.persistTo(le.b)
+
+	leaseTotalTTLs.Observe(float64(l.ttl))
+	leaseGranted.Inc()
+
+	if le.isPrimary() {
+		item := &LeaseWithTime{id: l.ID, time: l.expiry}
+		le.leaseExpiredNotifier.RegisterOrUpdate(item)
+		le.scheduleCheckpointIfNeeded(l)
+	}
+
+	return l, nil
+}
+
+func (le *lessor) Revoke(id LeaseID) error {
+	le.mu.Lock()
+
+	l := le.leaseMap[id]
+	if l == nil {
+		le.mu.Unlock()
+		return ErrLeaseNotFound
+	}
+
+	defer close(l.revokec)
+	// unlock before doing external work
+	le.mu.Unlock()
+
+	if le.rd == nil {
+		return nil
+	}
+
+	txn := le.rd()
+
+	// sort keys so deletes are in same order among all members,
+	// otherwise the backend hashes will be different
+	keys := l.Keys()
+	sort.StringSlice(keys).Sort()
+	for _, key := range keys {
+		txn.DeleteRange([]byte(key), nil)
+	}
+
+	le.mu.Lock()
+	defer le.mu.Unlock()
+	delete(le.leaseMap, l.ID)
+	// lease deletion needs to be in the same backend transaction with the
+	// kv deletion. Or we might end up with not executing the revoke or not
+	// deleting the keys if etcdserver fails in between.
+	schema.UnsafeDeleteLease(le.b.BatchTx(), &leasepb.Lease{ID: int64(l.ID)})
+
+	txn.End()
+
+	leaseRevoked.Inc()
+	return nil
+}
+
+func (le *lessor) Checkpoint(id LeaseID, remainingTTL int64) error {
+	le.mu.Lock()
+	defer le.mu.Unlock()
+
+	if l, ok := le.leaseMap[id]; ok {
+		// when checkpointing, we only update the remainingTTL, Promote is responsible for applying this to lease expiry
+		l.remainingTTL = remainingTTL
+		if le.shouldPersistCheckpoints() {
+			l.persistTo(le.b)
+		}
+		if le.isPrimary() {
+			// schedule the next checkpoint as needed
+			le.scheduleCheckpointIfNeeded(l)
+		}
+	}
+	return nil
+}
+
+func (le *lessor) shouldPersistCheckpoints() bool {
+	cv := le.cluster.Version()
+	return le.checkpointPersist || (cv != nil && greaterOrEqual(*cv, version.V3_6))
+}
+
+func greaterOrEqual(first, second semver.Version) bool {
+	return !version.LessThan(first, second)
+}
+
+// Renew renews an existing lease. If the given lease does not exist or
+// has expired, an error will be returned.
+func (le *lessor) Renew(id LeaseID) (int64, error) {
+	le.mu.RLock()
+	if !le.isPrimary() {
+		// forward renew request to primary instead of returning error.
+		le.mu.RUnlock()
+		return -1, ErrNotPrimary
+	}
+
+	demotec := le.demotec
+
+	l := le.leaseMap[id]
+	if l == nil {
+		le.mu.RUnlock()
+		return -1, ErrLeaseNotFound
+	}
+	// Clear remaining TTL when we renew if it is set
+	clearRemainingTTL := le.cp != nil && l.remainingTTL > 0
+
+	le.mu.RUnlock()
+	if l.expired() {
+		select {
+		// A expired lease might be pending for revoking or going through
+		// quorum to be revoked. To be accurate, renew request must wait for the
+		// deletion to complete.
+		case <-l.revokec:
+			return -1, ErrLeaseNotFound
+		// The expired lease might fail to be revoked if the primary changes.
+		// The caller will retry on ErrNotPrimary.
+		case <-demotec:
+			return -1, ErrNotPrimary
+		case <-le.stopC:
+			return -1, ErrNotPrimary
+		}
+	}
+
+	// gofail: var beforeCheckpointInLeaseRenew struct{}
+
+	// Clear remaining TTL when we renew if it is set
+	// By applying a RAFT entry only when the remainingTTL is already set, we limit the number
+	// of RAFT entries written per lease to a max of 2 per checkpoint interval.
+	if clearRemainingTTL {
+		if err := le.cp(context.Background(), &pb.LeaseCheckpointRequest{Checkpoints: []*pb.LeaseCheckpoint{{ID: int64(l.ID), Remaining_TTL: 0}}}); err != nil {
+			return -1, err
+		}
+	}
+
+	le.mu.Lock()
+	// Re-check in case the lease was revoked immediately after the previous check
+	l = le.leaseMap[id]
+	if l == nil {
+		le.mu.Unlock()
+		return -1, ErrLeaseNotFound
+	}
+	l.refresh(0)
+	item := &LeaseWithTime{id: l.ID, time: l.expiry}
+	le.leaseExpiredNotifier.RegisterOrUpdate(item)
+	le.mu.Unlock()
+
+	leaseRenewed.Inc()
+	return l.ttl, nil
+}
+
+func (le *lessor) Lookup(id LeaseID) *Lease {
+	le.mu.RLock()
+	defer le.mu.RUnlock()
+	return le.leaseMap[id]
+}
+
+func (le *lessor) unsafeLeases() []*Lease {
+	leases := make([]*Lease, 0, len(le.leaseMap))
+	for _, l := range le.leaseMap {
+		leases = append(leases, l)
+	}
+	return leases
+}
+
+func (le *lessor) Leases() []*Lease {
+	le.mu.RLock()
+	ls := le.unsafeLeases()
+	le.mu.RUnlock()
+	sort.Sort(leasesByExpiry(ls))
+	return ls
+}
+
+func (le *lessor) Promote(extend time.Duration) {
+	le.mu.Lock()
+	defer le.mu.Unlock()
+
+	le.demotec = make(chan struct{})
+
+	// refresh the expiries of all leases.
+	for _, l := range le.leaseMap {
+		l.refresh(extend)
+		item := &LeaseWithTime{id: l.ID, time: l.expiry}
+		le.leaseExpiredNotifier.RegisterOrUpdate(item)
+		le.scheduleCheckpointIfNeeded(l)
+	}
+
+	if len(le.leaseMap) < le.leaseRevokeRate {
+		// no possibility of lease pile-up
+		return
+	}
+
+	// adjust expiries in case of overlap
+	leases := le.unsafeLeases()
+	sort.Sort(leasesByExpiry(leases))
+
+	baseWindow := leases[0].Remaining()
+	nextWindow := baseWindow + time.Second
+	expires := 0
+	// have fewer expires than the total revoke rate so piled up leases
+	// don't consume the entire revoke limit
+	targetExpiresPerSecond := (3 * le.leaseRevokeRate) / 4
+	for _, l := range leases {
+		remaining := l.Remaining()
+		if remaining > nextWindow {
+			baseWindow = remaining
+			nextWindow = baseWindow + time.Second
+			expires = 1
+			continue
+		}
+		expires++
+		if expires <= targetExpiresPerSecond {
+			continue
+		}
+		rateDelay := float64(time.Second) * (float64(expires) / float64(targetExpiresPerSecond))
+		// If leases are extended by n seconds, leases n seconds ahead of the
+		// base window should be extended by only one second.
+		rateDelay -= float64(remaining - baseWindow)
+		delay := time.Duration(rateDelay)
+		nextWindow = baseWindow + delay
+		l.refresh(delay + extend)
+		item := &LeaseWithTime{id: l.ID, time: l.expiry}
+		le.leaseExpiredNotifier.RegisterOrUpdate(item)
+		le.scheduleCheckpointIfNeeded(l)
+	}
+}
+
+func (le *lessor) Demote() {
+	le.mu.Lock()
+	defer le.mu.Unlock()
+
+	// set the expiries of all leases to forever
+	for _, l := range le.leaseMap {
+		l.forever()
+	}
+
+	le.clearScheduledLeasesCheckpoints()
+	le.clearLeaseExpiredNotifier()
+
+	if le.demotec != nil {
+		close(le.demotec)
+		le.demotec = nil
+	}
+}
+
+// Attach attaches items to the lease with given ID. When the lease
+// expires, the attached items will be automatically removed.
+// If the given lease does not exist, an error will be returned.
+func (le *lessor) Attach(id LeaseID, items []LeaseItem) error {
+	le.mu.Lock()
+	defer le.mu.Unlock()
+
+	l := le.leaseMap[id]
+	if l == nil {
+		return ErrLeaseNotFound
+	}
+
+	l.mu.Lock()
+	for _, it := range items {
+		l.itemSet[it] = struct{}{}
+		le.itemMap[it] = id
+	}
+	l.mu.Unlock()
+	return nil
+}
+
+func (le *lessor) GetLease(item LeaseItem) LeaseID {
+	le.mu.RLock()
+	id := le.itemMap[item]
+	le.mu.RUnlock()
+	return id
+}
+
+// Detach detaches items from the lease with given ID.
+// If the given lease does not exist, an error will be returned.
+func (le *lessor) Detach(id LeaseID, items []LeaseItem) error {
+	le.mu.Lock()
+	defer le.mu.Unlock()
+
+	l := le.leaseMap[id]
+	if l == nil {
+		return ErrLeaseNotFound
+	}
+
+	l.mu.Lock()
+	for _, it := range items {
+		delete(l.itemSet, it)
+		delete(le.itemMap, it)
+	}
+	l.mu.Unlock()
+	return nil
+}
+
+func (le *lessor) Recover(b backend.Backend, rd RangeDeleter) {
+	le.mu.Lock()
+	defer le.mu.Unlock()
+
+	le.b = b
+	le.rd = rd
+	le.leaseMap = make(map[LeaseID]*Lease)
+	le.itemMap = make(map[LeaseItem]LeaseID)
+	le.initAndRecover()
+}
+
+func (le *lessor) ExpiredLeasesC() <-chan []*Lease {
+	return le.expiredC
+}
+
+func (le *lessor) Stop() {
+	close(le.stopC)
+	<-le.doneC
+}
+
+func (le *lessor) runLoop() {
+	defer close(le.doneC)
+
+	delayTicker := time.NewTicker(500 * time.Millisecond)
+	defer delayTicker.Stop()
+
+	for {
+		le.revokeExpiredLeases()
+		le.checkpointScheduledLeases()
+
+		select {
+		case <-delayTicker.C:
+		case <-le.stopC:
+			return
+		}
+	}
+}
+
+// revokeExpiredLeases finds all leases past their expiry and sends them to expired channel for
+// to be revoked.
+func (le *lessor) revokeExpiredLeases() {
+	var ls []*Lease
+
+	// rate limit
+	revokeLimit := le.leaseRevokeRate / 2
+
+	le.mu.RLock()
+	if le.isPrimary() {
+		ls = le.findExpiredLeases(revokeLimit)
+	}
+	le.mu.RUnlock()
+
+	if len(ls) != 0 {
+		select {
+		case <-le.stopC:
+			return
+		case le.expiredC <- ls:
+		default:
+			// the receiver of expiredC is probably busy handling
+			// other stuff
+			// let's try this next time after 500ms
+		}
+	}
+}
+
+// checkpointScheduledLeases finds all scheduled lease checkpoints that are due and
+// submits them to the checkpointer to persist them to the consensus log.
+func (le *lessor) checkpointScheduledLeases() {
+	// rate limit
+	for i := 0; i < leaseCheckpointRate/2; i++ {
+		var cps []*pb.LeaseCheckpoint
+
+		le.mu.Lock()
+		if le.isPrimary() {
+			cps = le.findDueScheduledCheckpoints(maxLeaseCheckpointBatchSize)
+		}
+		le.mu.Unlock()
+
+		if len(cps) != 0 {
+			if err := le.cp(context.Background(), &pb.LeaseCheckpointRequest{Checkpoints: cps}); err != nil {
+				return
+			}
+		}
+		if len(cps) < maxLeaseCheckpointBatchSize {
+			return
+		}
+	}
+}
+
+func (le *lessor) clearScheduledLeasesCheckpoints() {
+	le.leaseCheckpointHeap = make(LeaseQueue, 0)
+}
+
+func (le *lessor) clearLeaseExpiredNotifier() {
+	le.leaseExpiredNotifier = newLeaseExpiredNotifier()
+}
+
+// expireExists returns "l" which is not nil if expiry items exist.
+// It pops only when expiry item exists.
+// "next" is true, to indicate that it may exist in next attempt.
+func (le *lessor) expireExists() (l *Lease, next bool) {
+	if le.leaseExpiredNotifier.Len() == 0 {
+		return nil, false
+	}
+
+	item := le.leaseExpiredNotifier.Peek()
+	l = le.leaseMap[item.id]
+	if l == nil {
+		// lease has expired or been revoked
+		// no need to revoke (nothing is expiry)
+		le.leaseExpiredNotifier.Unregister() // O(log N)
+		return nil, true
+	}
+	now := time.Now()
+	if now.Before(item.time) /* item.time: expiration time */ {
+		// Candidate expirations are caught up, reinsert this item
+		// and no need to revoke (nothing is expiry)
+		return nil, false
+	}
+
+	// recheck if revoke is complete after retry interval
+	item.time = now.Add(le.expiredLeaseRetryInterval)
+	le.leaseExpiredNotifier.RegisterOrUpdate(item)
+	return l, false
+}
+
+// findExpiredLeases loops leases in the leaseMap until reaching expired limit
+// and returns the expired leases that needed to be revoked.
+func (le *lessor) findExpiredLeases(limit int) []*Lease {
+	leases := make([]*Lease, 0, 16)
+
+	for {
+		l, next := le.expireExists()
+		if l == nil && !next {
+			break
+		}
+		if next {
+			continue
+		}
+
+		if l.expired() {
+			leases = append(leases, l)
+
+			// reach expired limit
+			if len(leases) == limit {
+				break
+			}
+		}
+	}
+
+	return leases
+}
+
+func (le *lessor) scheduleCheckpointIfNeeded(lease *Lease) {
+	if le.cp == nil {
+		return
+	}
+
+	if lease.getRemainingTTL() > int64(le.checkpointInterval.Seconds()) {
+		if le.lg != nil {
+			le.lg.Debug("Scheduling lease checkpoint",
+				zap.Int64("leaseID", int64(lease.ID)),
+				zap.Duration("intervalSeconds", le.checkpointInterval),
+			)
+		}
+		heap.Push(&le.leaseCheckpointHeap, &LeaseWithTime{
+			id:   lease.ID,
+			time: time.Now().Add(le.checkpointInterval),
+		})
+	}
+}
+
+func (le *lessor) findDueScheduledCheckpoints(checkpointLimit int) []*pb.LeaseCheckpoint {
+	if le.cp == nil {
+		return nil
+	}
+
+	now := time.Now()
+	var cps []*pb.LeaseCheckpoint
+	for le.leaseCheckpointHeap.Len() > 0 && len(cps) < checkpointLimit {
+		lt := le.leaseCheckpointHeap[0]
+		if lt.time.After(now) /* lt.time: next checkpoint time */ {
+			return cps
+		}
+		heap.Pop(&le.leaseCheckpointHeap)
+		var l *Lease
+		var ok bool
+		if l, ok = le.leaseMap[lt.id]; !ok {
+			continue
+		}
+		if !now.Before(l.expiry) {
+			continue
+		}
+		remainingTTL := int64(math.Ceil(l.expiry.Sub(now).Seconds()))
+		if remainingTTL >= l.ttl {
+			continue
+		}
+		if le.lg != nil {
+			le.lg.Debug("Checkpointing lease",
+				zap.Int64("leaseID", int64(lt.id)),
+				zap.Int64("remainingTTL", remainingTTL),
+			)
+		}
+		cps = append(cps, &pb.LeaseCheckpoint{ID: int64(lt.id), Remaining_TTL: remainingTTL})
+	}
+	return cps
+}
+
+func (le *lessor) initAndRecover() {
+	tx := le.b.BatchTx()
+
+	tx.LockOutsideApply()
+	schema.UnsafeCreateLeaseBucket(tx)
+	lpbs := schema.MustUnsafeGetAllLeases(tx)
+	tx.Unlock()
+	for _, lpb := range lpbs {
+		ID := LeaseID(lpb.ID)
+		if lpb.TTL < le.minLeaseTTL {
+			lpb.TTL = le.minLeaseTTL
+		}
+		le.leaseMap[ID] = &Lease{
+			ID:  ID,
+			ttl: lpb.TTL,
+			// itemSet will be filled in when recover key-value pairs
+			// set expiry to forever, refresh when promoted
+			itemSet:      make(map[LeaseItem]struct{}),
+			expiry:       forever,
+			revokec:      make(chan struct{}),
+			remainingTTL: lpb.RemainingTTL,
+		}
+	}
+	le.leaseExpiredNotifier.Init()
+	heap.Init(&le.leaseCheckpointHeap)
+
+	le.b.ForceCommit()
+}
+
+// FakeLessor is a fake implementation of Lessor interface.
+// Used for testing only.
+type FakeLessor struct {
+	LeaseSet map[LeaseID]struct{}
+}
+
+func (fl *FakeLessor) SetRangeDeleter(dr RangeDeleter) {}
+
+func (fl *FakeLessor) SetCheckpointer(cp Checkpointer) {}
+
+func (fl *FakeLessor) Grant(id LeaseID, ttl int64) (*Lease, error) {
+	fl.LeaseSet[id] = struct{}{}
+	return nil, nil
+}
+
+func (fl *FakeLessor) Revoke(id LeaseID) error { return nil }
+
+func (fl *FakeLessor) Checkpoint(id LeaseID, remainingTTL int64) error { return nil }
+
+func (fl *FakeLessor) Attach(id LeaseID, items []LeaseItem) error { return nil }
+
+func (fl *FakeLessor) GetLease(item LeaseItem) LeaseID            { return 0 }
+func (fl *FakeLessor) Detach(id LeaseID, items []LeaseItem) error { return nil }
+
+func (fl *FakeLessor) Promote(extend time.Duration) {}
+
+func (fl *FakeLessor) Demote() {}
+
+func (fl *FakeLessor) Renew(id LeaseID) (int64, error) { return 10, nil }
+
+func (fl *FakeLessor) Lookup(id LeaseID) *Lease {
+	if _, ok := fl.LeaseSet[id]; ok {
+		return &Lease{ID: id}
+	}
+	return nil
+}
+
+func (fl *FakeLessor) Leases() []*Lease { return nil }
+
+func (fl *FakeLessor) ExpiredLeasesC() <-chan []*Lease { return nil }
+
+func (fl *FakeLessor) Recover(b backend.Backend, rd RangeDeleter) {}
+
+func (fl *FakeLessor) Stop() {}
+
+type FakeTxnDelete struct {
+	backend.BatchTx
+}
+
+func (ftd *FakeTxnDelete) DeleteRange(key, end []byte) (n, rev int64) { return 0, 0 }
+func (ftd *FakeTxnDelete) End()                                       { ftd.Unlock() }
diff --git a/vendor/go.etcd.io/etcd/server/v3/lease/metrics.go b/vendor/go.etcd.io/etcd/server/v3/lease/metrics.go
new file mode 100644
index 0000000..e38105e
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/lease/metrics.go
@@ -0,0 +1,60 @@
+// Copyright 2018 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package lease
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+var (
+	leaseGranted = prometheus.NewCounter(prometheus.CounterOpts{
+		Namespace: "etcd_debugging",
+		Subsystem: "lease",
+		Name:      "granted_total",
+		Help:      "The total number of granted leases.",
+	})
+
+	leaseRevoked = prometheus.NewCounter(prometheus.CounterOpts{
+		Namespace: "etcd_debugging",
+		Subsystem: "lease",
+		Name:      "revoked_total",
+		Help:      "The total number of revoked leases.",
+	})
+
+	leaseRenewed = prometheus.NewCounter(prometheus.CounterOpts{
+		Namespace: "etcd_debugging",
+		Subsystem: "lease",
+		Name:      "renewed_total",
+		Help:      "The number of renewed leases seen by the leader.",
+	})
+
+	leaseTotalTTLs = prometheus.NewHistogram(
+		prometheus.HistogramOpts{
+			Namespace: "etcd_debugging",
+			Subsystem: "lease",
+			Name:      "ttl_total",
+			Help:      "Bucketed histogram of lease TTLs.",
+			// 1 second -> 3 months
+			Buckets: prometheus.ExponentialBuckets(1, 2, 24),
+		},
+	)
+)
+
+func init() {
+	prometheus.MustRegister(leaseGranted)
+	prometheus.MustRegister(leaseRevoked)
+	prometheus.MustRegister(leaseRenewed)
+	prometheus.MustRegister(leaseTotalTTLs)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/proxy/grpcproxy/adapter/auth_client_adapter.go b/vendor/go.etcd.io/etcd/server/v3/proxy/grpcproxy/adapter/auth_client_adapter.go
new file mode 100644
index 0000000..0baa10c
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/proxy/grpcproxy/adapter/auth_client_adapter.go
@@ -0,0 +1,97 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package adapter
+
+import (
+	"context"
+
+	grpc "google.golang.org/grpc"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+)
+
+type as2ac struct{ as pb.AuthServer }
+
+func AuthServerToAuthClient(as pb.AuthServer) pb.AuthClient {
+	return &as2ac{as}
+}
+
+func (s *as2ac) AuthEnable(ctx context.Context, in *pb.AuthEnableRequest, opts ...grpc.CallOption) (*pb.AuthEnableResponse, error) {
+	return s.as.AuthEnable(ctx, in)
+}
+
+func (s *as2ac) AuthDisable(ctx context.Context, in *pb.AuthDisableRequest, opts ...grpc.CallOption) (*pb.AuthDisableResponse, error) {
+	return s.as.AuthDisable(ctx, in)
+}
+
+func (s *as2ac) AuthStatus(ctx context.Context, in *pb.AuthStatusRequest, opts ...grpc.CallOption) (*pb.AuthStatusResponse, error) {
+	return s.as.AuthStatus(ctx, in)
+}
+
+func (s *as2ac) Authenticate(ctx context.Context, in *pb.AuthenticateRequest, opts ...grpc.CallOption) (*pb.AuthenticateResponse, error) {
+	return s.as.Authenticate(ctx, in)
+}
+
+func (s *as2ac) RoleAdd(ctx context.Context, in *pb.AuthRoleAddRequest, opts ...grpc.CallOption) (*pb.AuthRoleAddResponse, error) {
+	return s.as.RoleAdd(ctx, in)
+}
+
+func (s *as2ac) RoleDelete(ctx context.Context, in *pb.AuthRoleDeleteRequest, opts ...grpc.CallOption) (*pb.AuthRoleDeleteResponse, error) {
+	return s.as.RoleDelete(ctx, in)
+}
+
+func (s *as2ac) RoleGet(ctx context.Context, in *pb.AuthRoleGetRequest, opts ...grpc.CallOption) (*pb.AuthRoleGetResponse, error) {
+	return s.as.RoleGet(ctx, in)
+}
+
+func (s *as2ac) RoleList(ctx context.Context, in *pb.AuthRoleListRequest, opts ...grpc.CallOption) (*pb.AuthRoleListResponse, error) {
+	return s.as.RoleList(ctx, in)
+}
+
+func (s *as2ac) RoleRevokePermission(ctx context.Context, in *pb.AuthRoleRevokePermissionRequest, opts ...grpc.CallOption) (*pb.AuthRoleRevokePermissionResponse, error) {
+	return s.as.RoleRevokePermission(ctx, in)
+}
+
+func (s *as2ac) RoleGrantPermission(ctx context.Context, in *pb.AuthRoleGrantPermissionRequest, opts ...grpc.CallOption) (*pb.AuthRoleGrantPermissionResponse, error) {
+	return s.as.RoleGrantPermission(ctx, in)
+}
+
+func (s *as2ac) UserDelete(ctx context.Context, in *pb.AuthUserDeleteRequest, opts ...grpc.CallOption) (*pb.AuthUserDeleteResponse, error) {
+	return s.as.UserDelete(ctx, in)
+}
+
+func (s *as2ac) UserAdd(ctx context.Context, in *pb.AuthUserAddRequest, opts ...grpc.CallOption) (*pb.AuthUserAddResponse, error) {
+	return s.as.UserAdd(ctx, in)
+}
+
+func (s *as2ac) UserGet(ctx context.Context, in *pb.AuthUserGetRequest, opts ...grpc.CallOption) (*pb.AuthUserGetResponse, error) {
+	return s.as.UserGet(ctx, in)
+}
+
+func (s *as2ac) UserList(ctx context.Context, in *pb.AuthUserListRequest, opts ...grpc.CallOption) (*pb.AuthUserListResponse, error) {
+	return s.as.UserList(ctx, in)
+}
+
+func (s *as2ac) UserGrantRole(ctx context.Context, in *pb.AuthUserGrantRoleRequest, opts ...grpc.CallOption) (*pb.AuthUserGrantRoleResponse, error) {
+	return s.as.UserGrantRole(ctx, in)
+}
+
+func (s *as2ac) UserRevokeRole(ctx context.Context, in *pb.AuthUserRevokeRoleRequest, opts ...grpc.CallOption) (*pb.AuthUserRevokeRoleResponse, error) {
+	return s.as.UserRevokeRole(ctx, in)
+}
+
+func (s *as2ac) UserChangePassword(ctx context.Context, in *pb.AuthUserChangePasswordRequest, opts ...grpc.CallOption) (*pb.AuthUserChangePasswordResponse, error) {
+	return s.as.UserChangePassword(ctx, in)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/proxy/grpcproxy/adapter/chan_stream.go b/vendor/go.etcd.io/etcd/server/v3/proxy/grpcproxy/adapter/chan_stream.go
new file mode 100644
index 0000000..802c841
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/proxy/grpcproxy/adapter/chan_stream.go
@@ -0,0 +1,166 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package adapter
+
+import (
+	"context"
+	"maps"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/metadata"
+	"google.golang.org/grpc/status"
+)
+
+// chanServerStream implements grpc.ServerStream with a chanStream
+type chanServerStream struct {
+	headerc  chan<- metadata.MD
+	trailerc chan<- metadata.MD
+	grpc.Stream
+
+	headers []metadata.MD
+}
+
+func (ss *chanServerStream) SendHeader(md metadata.MD) error {
+	if ss.headerc == nil {
+		return errAlreadySentHeader
+	}
+	outmd := make(map[string][]string)
+	for _, h := range append(ss.headers, md) {
+		maps.Copy(outmd, h)
+	}
+	select {
+	case ss.headerc <- outmd:
+		ss.headerc = nil
+		ss.headers = nil
+		return nil
+	case <-ss.Context().Done():
+	}
+	return ss.Context().Err()
+}
+
+func (ss *chanServerStream) SetHeader(md metadata.MD) error {
+	if ss.headerc == nil {
+		return errAlreadySentHeader
+	}
+	ss.headers = append(ss.headers, md)
+	return nil
+}
+
+func (ss *chanServerStream) SetTrailer(md metadata.MD) {
+	ss.trailerc <- md
+}
+
+// chanClientStream implements grpc.ClientStream with a chanStream
+type chanClientStream struct {
+	headerc  <-chan metadata.MD
+	trailerc <-chan metadata.MD
+	*chanStream
+}
+
+func (cs *chanClientStream) Header() (metadata.MD, error) {
+	select {
+	case md := <-cs.headerc:
+		return md, nil
+	case <-cs.Context().Done():
+	}
+	return nil, cs.Context().Err()
+}
+
+func (cs *chanClientStream) Trailer() metadata.MD {
+	select {
+	case md := <-cs.trailerc:
+		return md
+	case <-cs.Context().Done():
+		return nil
+	}
+}
+
+func (cs *chanClientStream) CloseSend() error {
+	close(cs.chanStream.sendc)
+	return nil
+}
+
+// chanStream implements grpc.Stream using channels
+type chanStream struct {
+	recvc  <-chan any
+	sendc  chan<- any
+	ctx    context.Context
+	cancel context.CancelFunc
+}
+
+func (s *chanStream) Context() context.Context { return s.ctx }
+
+func (s *chanStream) SendMsg(m any) error {
+	select {
+	case s.sendc <- m:
+		if err, ok := m.(error); ok {
+			return err
+		}
+		return nil
+	case <-s.ctx.Done():
+	}
+	return s.ctx.Err()
+}
+
+func (s *chanStream) RecvMsg(m any) error {
+	v := m.(*any)
+	for {
+		select {
+		case msg, ok := <-s.recvc:
+			if !ok {
+				return status.Error(codes.Canceled, "the client connection is closing")
+			}
+			if err, ok := msg.(error); ok {
+				return err
+			}
+			*v = msg
+			return nil
+		case <-s.ctx.Done():
+		}
+		if len(s.recvc) == 0 {
+			// prioritize any pending recv messages over canceled context
+			break
+		}
+	}
+	return s.ctx.Err()
+}
+
+func newPipeStream(ctx context.Context, ssHandler func(chanServerStream) error) chanClientStream {
+	// ch1 is buffered so server can send error on close
+	ch1, ch2 := make(chan any, 1), make(chan any)
+	headerc, trailerc := make(chan metadata.MD, 1), make(chan metadata.MD, 1)
+
+	cctx, ccancel := context.WithCancel(ctx)
+	cli := &chanStream{recvc: ch1, sendc: ch2, ctx: cctx, cancel: ccancel}
+	cs := chanClientStream{headerc, trailerc, cli}
+
+	sctx, scancel := context.WithCancel(ctx)
+	srv := &chanStream{recvc: ch2, sendc: ch1, ctx: sctx, cancel: scancel}
+	ss := chanServerStream{headerc, trailerc, srv, nil}
+
+	go func() {
+		if err := ssHandler(ss); err != nil {
+			select {
+			case srv.sendc <- err:
+			case <-sctx.Done():
+			case <-cctx.Done():
+			}
+		}
+		scancel()
+		ccancel()
+	}()
+	return cs
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/proxy/grpcproxy/adapter/cluster_client_adapter.go b/vendor/go.etcd.io/etcd/server/v3/proxy/grpcproxy/adapter/cluster_client_adapter.go
new file mode 100644
index 0000000..4c9fbbb
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/proxy/grpcproxy/adapter/cluster_client_adapter.go
@@ -0,0 +1,49 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package adapter
+
+import (
+	"context"
+
+	"google.golang.org/grpc"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+)
+
+type cls2clc struct{ cls pb.ClusterServer }
+
+func ClusterServerToClusterClient(cls pb.ClusterServer) pb.ClusterClient {
+	return &cls2clc{cls}
+}
+
+func (s *cls2clc) MemberList(ctx context.Context, r *pb.MemberListRequest, opts ...grpc.CallOption) (*pb.MemberListResponse, error) {
+	return s.cls.MemberList(ctx, r)
+}
+
+func (s *cls2clc) MemberAdd(ctx context.Context, r *pb.MemberAddRequest, opts ...grpc.CallOption) (*pb.MemberAddResponse, error) {
+	return s.cls.MemberAdd(ctx, r)
+}
+
+func (s *cls2clc) MemberUpdate(ctx context.Context, r *pb.MemberUpdateRequest, opts ...grpc.CallOption) (*pb.MemberUpdateResponse, error) {
+	return s.cls.MemberUpdate(ctx, r)
+}
+
+func (s *cls2clc) MemberRemove(ctx context.Context, r *pb.MemberRemoveRequest, opts ...grpc.CallOption) (*pb.MemberRemoveResponse, error) {
+	return s.cls.MemberRemove(ctx, r)
+}
+
+func (s *cls2clc) MemberPromote(ctx context.Context, r *pb.MemberPromoteRequest, opts ...grpc.CallOption) (*pb.MemberPromoteResponse, error) {
+	return s.cls.MemberPromote(ctx, r)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/proxy/grpcproxy/adapter/doc.go b/vendor/go.etcd.io/etcd/server/v3/proxy/grpcproxy/adapter/doc.go
new file mode 100644
index 0000000..7170be2
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/proxy/grpcproxy/adapter/doc.go
@@ -0,0 +1,17 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package adapter provides gRPC adapters between client and server
+// gRPC interfaces without needing to go through a gRPC connection.
+package adapter
diff --git a/vendor/go.etcd.io/etcd/server/v3/proxy/grpcproxy/adapter/election_client_adapter.go b/vendor/go.etcd.io/etcd/server/v3/proxy/grpcproxy/adapter/election_client_adapter.go
new file mode 100644
index 0000000..c7edaf7
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/proxy/grpcproxy/adapter/election_client_adapter.go
@@ -0,0 +1,82 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package adapter
+
+import (
+	"context"
+
+	"google.golang.org/grpc"
+
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v3election/v3electionpb"
+)
+
+type es2ec struct{ es v3electionpb.ElectionServer }
+
+func ElectionServerToElectionClient(es v3electionpb.ElectionServer) v3electionpb.ElectionClient {
+	return &es2ec{es}
+}
+
+func (s *es2ec) Campaign(ctx context.Context, r *v3electionpb.CampaignRequest, opts ...grpc.CallOption) (*v3electionpb.CampaignResponse, error) {
+	return s.es.Campaign(ctx, r)
+}
+
+func (s *es2ec) Proclaim(ctx context.Context, r *v3electionpb.ProclaimRequest, opts ...grpc.CallOption) (*v3electionpb.ProclaimResponse, error) {
+	return s.es.Proclaim(ctx, r)
+}
+
+func (s *es2ec) Leader(ctx context.Context, r *v3electionpb.LeaderRequest, opts ...grpc.CallOption) (*v3electionpb.LeaderResponse, error) {
+	return s.es.Leader(ctx, r)
+}
+
+func (s *es2ec) Resign(ctx context.Context, r *v3electionpb.ResignRequest, opts ...grpc.CallOption) (*v3electionpb.ResignResponse, error) {
+	return s.es.Resign(ctx, r)
+}
+
+func (s *es2ec) Observe(ctx context.Context, in *v3electionpb.LeaderRequest, opts ...grpc.CallOption) (v3electionpb.Election_ObserveClient, error) {
+	cs := newPipeStream(ctx, func(ss chanServerStream) error {
+		return s.es.Observe(in, &es2ecServerStream{ss})
+	})
+	return &es2ecClientStream{cs}, nil
+}
+
+// es2ecClientStream implements Election_ObserveClient
+type es2ecClientStream struct{ chanClientStream }
+
+// es2ecServerStream implements Election_ObserveServer
+type es2ecServerStream struct{ chanServerStream }
+
+func (s *es2ecClientStream) Send(rr *v3electionpb.LeaderRequest) error {
+	return s.SendMsg(rr)
+}
+
+func (s *es2ecClientStream) Recv() (*v3electionpb.LeaderResponse, error) {
+	var v any
+	if err := s.RecvMsg(&v); err != nil {
+		return nil, err
+	}
+	return v.(*v3electionpb.LeaderResponse), nil
+}
+
+func (s *es2ecServerStream) Send(rr *v3electionpb.LeaderResponse) error {
+	return s.SendMsg(rr)
+}
+
+func (s *es2ecServerStream) Recv() (*v3electionpb.LeaderRequest, error) {
+	var v any
+	if err := s.RecvMsg(&v); err != nil {
+		return nil, err
+	}
+	return v.(*v3electionpb.LeaderRequest), nil
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/proxy/grpcproxy/adapter/kv_client_adapter.go b/vendor/go.etcd.io/etcd/server/v3/proxy/grpcproxy/adapter/kv_client_adapter.go
new file mode 100644
index 0000000..69e3a11
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/proxy/grpcproxy/adapter/kv_client_adapter.go
@@ -0,0 +1,49 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package adapter
+
+import (
+	"context"
+
+	grpc "google.golang.org/grpc"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+)
+
+type kvs2kvc struct{ kvs pb.KVServer }
+
+func KvServerToKvClient(kvs pb.KVServer) pb.KVClient {
+	return &kvs2kvc{kvs}
+}
+
+func (s *kvs2kvc) Range(ctx context.Context, in *pb.RangeRequest, opts ...grpc.CallOption) (*pb.RangeResponse, error) {
+	return s.kvs.Range(ctx, in)
+}
+
+func (s *kvs2kvc) Put(ctx context.Context, in *pb.PutRequest, opts ...grpc.CallOption) (*pb.PutResponse, error) {
+	return s.kvs.Put(ctx, in)
+}
+
+func (s *kvs2kvc) DeleteRange(ctx context.Context, in *pb.DeleteRangeRequest, opts ...grpc.CallOption) (*pb.DeleteRangeResponse, error) {
+	return s.kvs.DeleteRange(ctx, in)
+}
+
+func (s *kvs2kvc) Txn(ctx context.Context, in *pb.TxnRequest, opts ...grpc.CallOption) (*pb.TxnResponse, error) {
+	return s.kvs.Txn(ctx, in)
+}
+
+func (s *kvs2kvc) Compact(ctx context.Context, in *pb.CompactionRequest, opts ...grpc.CallOption) (*pb.CompactionResponse, error) {
+	return s.kvs.Compact(ctx, in)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/proxy/grpcproxy/adapter/lease_client_adapter.go b/vendor/go.etcd.io/etcd/server/v3/proxy/grpcproxy/adapter/lease_client_adapter.go
new file mode 100644
index 0000000..bf76a55
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/proxy/grpcproxy/adapter/lease_client_adapter.go
@@ -0,0 +1,84 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package adapter
+
+import (
+	"context"
+
+	"google.golang.org/grpc"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+)
+
+type ls2lc struct {
+	leaseServer pb.LeaseServer
+}
+
+func LeaseServerToLeaseClient(ls pb.LeaseServer) pb.LeaseClient {
+	return &ls2lc{ls}
+}
+
+func (c *ls2lc) LeaseGrant(ctx context.Context, in *pb.LeaseGrantRequest, opts ...grpc.CallOption) (*pb.LeaseGrantResponse, error) {
+	return c.leaseServer.LeaseGrant(ctx, in)
+}
+
+func (c *ls2lc) LeaseRevoke(ctx context.Context, in *pb.LeaseRevokeRequest, opts ...grpc.CallOption) (*pb.LeaseRevokeResponse, error) {
+	return c.leaseServer.LeaseRevoke(ctx, in)
+}
+
+func (c *ls2lc) LeaseKeepAlive(ctx context.Context, opts ...grpc.CallOption) (pb.Lease_LeaseKeepAliveClient, error) {
+	cs := newPipeStream(ctx, func(ss chanServerStream) error {
+		return c.leaseServer.LeaseKeepAlive(&ls2lcServerStream{ss})
+	})
+	return &ls2lcClientStream{cs}, nil
+}
+
+func (c *ls2lc) LeaseTimeToLive(ctx context.Context, in *pb.LeaseTimeToLiveRequest, opts ...grpc.CallOption) (*pb.LeaseTimeToLiveResponse, error) {
+	return c.leaseServer.LeaseTimeToLive(ctx, in)
+}
+
+func (c *ls2lc) LeaseLeases(ctx context.Context, in *pb.LeaseLeasesRequest, opts ...grpc.CallOption) (*pb.LeaseLeasesResponse, error) {
+	return c.leaseServer.LeaseLeases(ctx, in)
+}
+
+// ls2lcClientStream implements Lease_LeaseKeepAliveClient
+type ls2lcClientStream struct{ chanClientStream }
+
+// ls2lcServerStream implements Lease_LeaseKeepAliveServer
+type ls2lcServerStream struct{ chanServerStream }
+
+func (s *ls2lcClientStream) Send(rr *pb.LeaseKeepAliveRequest) error {
+	return s.SendMsg(rr)
+}
+
+func (s *ls2lcClientStream) Recv() (*pb.LeaseKeepAliveResponse, error) {
+	var v any
+	if err := s.RecvMsg(&v); err != nil {
+		return nil, err
+	}
+	return v.(*pb.LeaseKeepAliveResponse), nil
+}
+
+func (s *ls2lcServerStream) Send(rr *pb.LeaseKeepAliveResponse) error {
+	return s.SendMsg(rr)
+}
+
+func (s *ls2lcServerStream) Recv() (*pb.LeaseKeepAliveRequest, error) {
+	var v any
+	if err := s.RecvMsg(&v); err != nil {
+		return nil, err
+	}
+	return v.(*pb.LeaseKeepAliveRequest), nil
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/proxy/grpcproxy/adapter/lock_client_adapter.go b/vendor/go.etcd.io/etcd/server/v3/proxy/grpcproxy/adapter/lock_client_adapter.go
new file mode 100644
index 0000000..de5ba04
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/proxy/grpcproxy/adapter/lock_client_adapter.go
@@ -0,0 +1,37 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package adapter
+
+import (
+	"context"
+
+	"google.golang.org/grpc"
+
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v3lock/v3lockpb"
+)
+
+type ls2lsc struct{ ls v3lockpb.LockServer }
+
+func LockServerToLockClient(ls v3lockpb.LockServer) v3lockpb.LockClient {
+	return &ls2lsc{ls}
+}
+
+func (s *ls2lsc) Lock(ctx context.Context, r *v3lockpb.LockRequest, opts ...grpc.CallOption) (*v3lockpb.LockResponse, error) {
+	return s.ls.Lock(ctx, r)
+}
+
+func (s *ls2lsc) Unlock(ctx context.Context, r *v3lockpb.UnlockRequest, opts ...grpc.CallOption) (*v3lockpb.UnlockResponse, error) {
+	return s.ls.Unlock(ctx, r)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/proxy/grpcproxy/adapter/maintenance_client_adapter.go b/vendor/go.etcd.io/etcd/server/v3/proxy/grpcproxy/adapter/maintenance_client_adapter.go
new file mode 100644
index 0000000..7b20445
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/proxy/grpcproxy/adapter/maintenance_client_adapter.go
@@ -0,0 +1,94 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package adapter
+
+import (
+	"context"
+
+	"google.golang.org/grpc"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+)
+
+type mts2mtc struct{ mts pb.MaintenanceServer }
+
+func MaintenanceServerToMaintenanceClient(mts pb.MaintenanceServer) pb.MaintenanceClient {
+	return &mts2mtc{mts}
+}
+
+func (s *mts2mtc) Alarm(ctx context.Context, r *pb.AlarmRequest, opts ...grpc.CallOption) (*pb.AlarmResponse, error) {
+	return s.mts.Alarm(ctx, r)
+}
+
+func (s *mts2mtc) Status(ctx context.Context, r *pb.StatusRequest, opts ...grpc.CallOption) (*pb.StatusResponse, error) {
+	return s.mts.Status(ctx, r)
+}
+
+func (s *mts2mtc) Defragment(ctx context.Context, dr *pb.DefragmentRequest, opts ...grpc.CallOption) (*pb.DefragmentResponse, error) {
+	return s.mts.Defragment(ctx, dr)
+}
+
+func (s *mts2mtc) Hash(ctx context.Context, r *pb.HashRequest, opts ...grpc.CallOption) (*pb.HashResponse, error) {
+	return s.mts.Hash(ctx, r)
+}
+
+func (s *mts2mtc) HashKV(ctx context.Context, r *pb.HashKVRequest, opts ...grpc.CallOption) (*pb.HashKVResponse, error) {
+	return s.mts.HashKV(ctx, r)
+}
+
+func (s *mts2mtc) MoveLeader(ctx context.Context, r *pb.MoveLeaderRequest, opts ...grpc.CallOption) (*pb.MoveLeaderResponse, error) {
+	return s.mts.MoveLeader(ctx, r)
+}
+
+func (s *mts2mtc) Downgrade(ctx context.Context, r *pb.DowngradeRequest, opts ...grpc.CallOption) (*pb.DowngradeResponse, error) {
+	return s.mts.Downgrade(ctx, r)
+}
+
+func (s *mts2mtc) Snapshot(ctx context.Context, in *pb.SnapshotRequest, opts ...grpc.CallOption) (pb.Maintenance_SnapshotClient, error) {
+	cs := newPipeStream(ctx, func(ss chanServerStream) error {
+		return s.mts.Snapshot(in, &ss2scServerStream{ss})
+	})
+	return &ss2scClientStream{cs}, nil
+}
+
+// ss2scClientStream implements Maintenance_SnapshotClient
+type ss2scClientStream struct{ chanClientStream }
+
+// ss2scServerStream implements Maintenance_SnapshotServer
+type ss2scServerStream struct{ chanServerStream }
+
+func (s *ss2scClientStream) Send(rr *pb.SnapshotRequest) error {
+	return s.SendMsg(rr)
+}
+
+func (s *ss2scClientStream) Recv() (*pb.SnapshotResponse, error) {
+	var v any
+	if err := s.RecvMsg(&v); err != nil {
+		return nil, err
+	}
+	return v.(*pb.SnapshotResponse), nil
+}
+
+func (s *ss2scServerStream) Send(rr *pb.SnapshotResponse) error {
+	return s.SendMsg(rr)
+}
+
+func (s *ss2scServerStream) Recv() (*pb.SnapshotRequest, error) {
+	var v any
+	if err := s.RecvMsg(&v); err != nil {
+		return nil, err
+	}
+	return v.(*pb.SnapshotRequest), nil
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/proxy/grpcproxy/adapter/watch_client_adapter.go b/vendor/go.etcd.io/etcd/server/v3/proxy/grpcproxy/adapter/watch_client_adapter.go
new file mode 100644
index 0000000..828ed1b
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/proxy/grpcproxy/adapter/watch_client_adapter.go
@@ -0,0 +1,69 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package adapter
+
+import (
+	"context"
+	"errors"
+
+	"google.golang.org/grpc"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+)
+
+var errAlreadySentHeader = errors.New("adapter: already sent header")
+
+type ws2wc struct{ wserv pb.WatchServer }
+
+func WatchServerToWatchClient(wserv pb.WatchServer) pb.WatchClient {
+	return &ws2wc{wserv}
+}
+
+func (s *ws2wc) Watch(ctx context.Context, opts ...grpc.CallOption) (pb.Watch_WatchClient, error) {
+	cs := newPipeStream(ctx, func(ss chanServerStream) error {
+		return s.wserv.Watch(&ws2wcServerStream{ss})
+	})
+	return &ws2wcClientStream{cs}, nil
+}
+
+// ws2wcClientStream implements Watch_WatchClient
+type ws2wcClientStream struct{ chanClientStream }
+
+// ws2wcServerStream implements Watch_WatchServer
+type ws2wcServerStream struct{ chanServerStream }
+
+func (s *ws2wcClientStream) Send(wr *pb.WatchRequest) error {
+	return s.SendMsg(wr)
+}
+
+func (s *ws2wcClientStream) Recv() (*pb.WatchResponse, error) {
+	var v any
+	if err := s.RecvMsg(&v); err != nil {
+		return nil, err
+	}
+	return v.(*pb.WatchResponse), nil
+}
+
+func (s *ws2wcServerStream) Send(wr *pb.WatchResponse) error {
+	return s.SendMsg(wr)
+}
+
+func (s *ws2wcServerStream) Recv() (*pb.WatchRequest, error) {
+	var v any
+	if err := s.RecvMsg(&v); err != nil {
+		return nil, err
+	}
+	return v.(*pb.WatchRequest), nil
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/backend.go b/vendor/go.etcd.io/etcd/server/v3/storage/backend.go
new file mode 100644
index 0000000..7db61f9
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/backend.go
@@ -0,0 +1,114 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package storage
+
+import (
+	"fmt"
+	"os"
+	"time"
+
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/server/v3/config"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/snap"
+	"go.etcd.io/etcd/server/v3/storage/backend"
+	"go.etcd.io/etcd/server/v3/storage/schema"
+	"go.etcd.io/raft/v3/raftpb"
+)
+
+func newBackend(cfg config.ServerConfig, hooks backend.Hooks) backend.Backend {
+	bcfg := backend.DefaultBackendConfig(cfg.Logger)
+	bcfg.Path = cfg.BackendPath()
+	bcfg.UnsafeNoFsync = cfg.UnsafeNoFsync
+	if cfg.BackendBatchLimit != 0 {
+		bcfg.BatchLimit = cfg.BackendBatchLimit
+		if cfg.Logger != nil {
+			cfg.Logger.Info("setting backend batch limit", zap.Int("batch limit", cfg.BackendBatchLimit))
+		}
+	}
+	if cfg.BackendBatchInterval != 0 {
+		bcfg.BatchInterval = cfg.BackendBatchInterval
+		if cfg.Logger != nil {
+			cfg.Logger.Info("setting backend batch interval", zap.Duration("batch interval", cfg.BackendBatchInterval))
+		}
+	}
+	bcfg.BackendFreelistType = cfg.BackendFreelistType
+	bcfg.Logger = cfg.Logger
+	if cfg.QuotaBackendBytes > 0 && cfg.QuotaBackendBytes != DefaultQuotaBytes {
+		// permit 10% excess over quota for disarm
+		bcfg.MmapSize = uint64(cfg.QuotaBackendBytes + cfg.QuotaBackendBytes/10)
+	}
+	bcfg.Mlock = cfg.MemoryMlock
+	bcfg.Hooks = hooks
+	return backend.New(bcfg)
+}
+
+// OpenSnapshotBackend renames a snapshot db to the current etcd db and opens it.
+func OpenSnapshotBackend(cfg config.ServerConfig, ss *snap.Snapshotter, snapshot raftpb.Snapshot, hooks *BackendHooks) (backend.Backend, error) {
+	snapPath, err := ss.DBFilePath(snapshot.Metadata.Index)
+	if err != nil {
+		return nil, fmt.Errorf("failed to find database snapshot file (%w)", err)
+	}
+	if err := os.Rename(snapPath, cfg.BackendPath()); err != nil {
+		return nil, fmt.Errorf("failed to rename database snapshot file (%w)", err)
+	}
+	return OpenBackend(cfg, hooks), nil
+}
+
+// OpenBackend returns a backend using the current etcd db.
+func OpenBackend(cfg config.ServerConfig, hooks backend.Hooks) backend.Backend {
+	fn := cfg.BackendPath()
+
+	now, beOpened := time.Now(), make(chan backend.Backend)
+	go func() {
+		beOpened <- newBackend(cfg, hooks)
+	}()
+
+	defer func() {
+		cfg.Logger.Info("opened backend db", zap.String("path", fn), zap.Duration("took", time.Since(now)))
+	}()
+
+	select {
+	case be := <-beOpened:
+		return be
+
+	case <-time.After(10 * time.Second):
+		cfg.Logger.Info(
+			"db file is flocked by another process, or taking too long",
+			zap.String("path", fn),
+			zap.Duration("took", time.Since(now)),
+		)
+	}
+
+	return <-beOpened
+}
+
+// RecoverSnapshotBackend recovers the DB from a snapshot in case etcd crashes
+// before updating the backend db after persisting raft snapshot to disk,
+// violating the invariant snapshot.Metadata.Index < db.consistentIndex. In this
+// case, replace the db with the snapshot db sent by the leader.
+func RecoverSnapshotBackend(cfg config.ServerConfig, oldbe backend.Backend, snapshot raftpb.Snapshot, beExist bool, hooks *BackendHooks) (backend.Backend, error) {
+	consistentIndex := uint64(0)
+	if beExist {
+		consistentIndex, _ = schema.ReadConsistentIndex(oldbe.ReadTx())
+	}
+	if snapshot.Metadata.Index <= consistentIndex {
+		cfg.Logger.Info("Skipping snapshot backend", zap.Uint64("consistent-index", consistentIndex), zap.Uint64("snapshot-index", snapshot.Metadata.Index))
+		return oldbe, nil
+	}
+	cfg.Logger.Info("Recovering from snapshot backend", zap.Uint64("consistent-index", consistentIndex), zap.Uint64("snapshot-index", snapshot.Metadata.Index))
+	oldbe.Close()
+	return OpenSnapshotBackend(cfg, snap.New(cfg.Logger, cfg.SnapDir()), snapshot, hooks)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/backend/backend.go b/vendor/go.etcd.io/etcd/server/v3/storage/backend/backend.go
new file mode 100644
index 0000000..275064f
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/backend/backend.go
@@ -0,0 +1,724 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package backend
+
+import (
+	"fmt"
+	"hash/crc32"
+	"io"
+	"os"
+	"path/filepath"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	humanize "github.com/dustin/go-humanize"
+	"go.uber.org/zap"
+
+	bolt "go.etcd.io/bbolt"
+	"go.etcd.io/etcd/client/pkg/v3/verify"
+)
+
+var (
+	defaultBatchLimit    = 10000
+	defaultBatchInterval = 100 * time.Millisecond
+
+	defragLimit = 10000
+
+	// InitialMmapSize is the initial size of the mmapped region. Setting this larger than
+	// the potential max db size can prevent writer from blocking reader.
+	// This only works for linux.
+	InitialMmapSize = uint64(10 * 1024 * 1024 * 1024)
+
+	// minSnapshotWarningTimeout is the minimum threshold to trigger a long running snapshot warning.
+	minSnapshotWarningTimeout = 30 * time.Second
+)
+
+type Backend interface {
+	// ReadTx returns a read transaction. It is replaced by ConcurrentReadTx in the main data path, see #10523.
+	ReadTx() ReadTx
+	BatchTx() BatchTx
+	// ConcurrentReadTx returns a non-blocking read transaction.
+	ConcurrentReadTx() ReadTx
+
+	Snapshot() Snapshot
+	Hash(ignores func(bucketName, keyName []byte) bool) (uint32, error)
+	// Size returns the current size of the backend physically allocated.
+	// The backend can hold DB space that is not utilized at the moment,
+	// since it can conduct pre-allocation or spare unused space for recycling.
+	// Use SizeInUse() instead for the actual DB size.
+	Size() int64
+	// SizeInUse returns the current size of the backend logically in use.
+	// Since the backend can manage free space in a non-byte unit such as
+	// number of pages, the returned value can be not exactly accurate in bytes.
+	SizeInUse() int64
+	// OpenReadTxN returns the number of currently open read transactions in the backend.
+	OpenReadTxN() int64
+	Defrag() error
+	ForceCommit()
+	Close() error
+
+	// SetTxPostLockInsideApplyHook sets a txPostLockInsideApplyHook.
+	SetTxPostLockInsideApplyHook(func())
+}
+
+type Snapshot interface {
+	// Size gets the size of the snapshot.
+	Size() int64
+	// WriteTo writes the snapshot into the given writer.
+	WriteTo(w io.Writer) (n int64, err error)
+	// Close closes the snapshot.
+	Close() error
+}
+
+type txReadBufferCache struct {
+	mu         sync.Mutex
+	buf        *txReadBuffer
+	bufVersion uint64
+}
+
+type backend struct {
+	// size and commits are used with atomic operations so they must be
+	// 64-bit aligned, otherwise 32-bit tests will crash
+
+	// size is the number of bytes allocated in the backend
+	size int64
+	// sizeInUse is the number of bytes actually used in the backend
+	sizeInUse int64
+	// commits counts number of commits since start
+	commits int64
+	// openReadTxN is the number of currently open read transactions in the backend
+	openReadTxN int64
+	// mlock prevents backend database file to be swapped
+	mlock bool
+
+	mu    sync.RWMutex
+	bopts *bolt.Options
+	db    *bolt.DB
+
+	batchInterval time.Duration
+	batchLimit    int
+	batchTx       *batchTxBuffered
+
+	readTx *readTx
+	// txReadBufferCache mirrors "txReadBuffer" within "readTx" -- readTx.baseReadTx.buf.
+	// When creating "concurrentReadTx":
+	// - if the cache is up-to-date, "readTx.baseReadTx.buf" copy can be skipped
+	// - if the cache is empty or outdated, "readTx.baseReadTx.buf" copy is required
+	txReadBufferCache txReadBufferCache
+
+	stopc chan struct{}
+	donec chan struct{}
+
+	hooks Hooks
+
+	// txPostLockInsideApplyHook is called each time right after locking the tx.
+	txPostLockInsideApplyHook func()
+
+	lg *zap.Logger
+}
+
+type BackendConfig struct {
+	// Path is the file path to the backend file.
+	Path string
+	// BatchInterval is the maximum time before flushing the BatchTx.
+	BatchInterval time.Duration
+	// BatchLimit is the maximum puts before flushing the BatchTx.
+	BatchLimit int
+	// BackendFreelistType is the backend boltdb's freelist type.
+	BackendFreelistType bolt.FreelistType
+	// MmapSize is the number of bytes to mmap for the backend.
+	MmapSize uint64
+	// Logger logs backend-side operations.
+	Logger *zap.Logger
+	// UnsafeNoFsync disables all uses of fsync.
+	UnsafeNoFsync bool `json:"unsafe-no-fsync"`
+	// Mlock prevents backend database file to be swapped
+	Mlock bool
+
+	// Hooks are getting executed during lifecycle of Backend's transactions.
+	Hooks Hooks
+}
+
+type BackendConfigOption func(*BackendConfig)
+
+func DefaultBackendConfig(lg *zap.Logger) BackendConfig {
+	return BackendConfig{
+		BatchInterval: defaultBatchInterval,
+		BatchLimit:    defaultBatchLimit,
+		MmapSize:      InitialMmapSize,
+		Logger:        lg,
+	}
+}
+
+func New(bcfg BackendConfig) Backend {
+	return newBackend(bcfg)
+}
+
+func WithMmapSize(size uint64) BackendConfigOption {
+	return func(bcfg *BackendConfig) {
+		bcfg.MmapSize = size
+	}
+}
+
+func NewDefaultBackend(lg *zap.Logger, path string, opts ...BackendConfigOption) Backend {
+	bcfg := DefaultBackendConfig(lg)
+	bcfg.Path = path
+	for _, opt := range opts {
+		opt(&bcfg)
+	}
+
+	return newBackend(bcfg)
+}
+
+func newBackend(bcfg BackendConfig) *backend {
+	bopts := &bolt.Options{}
+	if boltOpenOptions != nil {
+		*bopts = *boltOpenOptions
+	}
+
+	if bcfg.Logger == nil {
+		bcfg.Logger = zap.NewNop()
+	}
+
+	bopts.InitialMmapSize = bcfg.mmapSize()
+	bopts.FreelistType = bcfg.BackendFreelistType
+	bopts.NoSync = bcfg.UnsafeNoFsync
+	bopts.NoGrowSync = bcfg.UnsafeNoFsync
+	bopts.Mlock = bcfg.Mlock
+	bopts.Logger = newBoltLoggerZap(bcfg)
+
+	db, err := bolt.Open(bcfg.Path, 0o600, bopts)
+	if err != nil {
+		bcfg.Logger.Panic("failed to open database", zap.String("path", bcfg.Path), zap.Error(err))
+	}
+
+	// In future, may want to make buffering optional for low-concurrency systems
+	// or dynamically swap between buffered/non-buffered depending on workload.
+	b := &backend{
+		bopts: bopts,
+		db:    db,
+
+		batchInterval: bcfg.BatchInterval,
+		batchLimit:    bcfg.BatchLimit,
+		mlock:         bcfg.Mlock,
+
+		readTx: &readTx{
+			baseReadTx: baseReadTx{
+				buf: txReadBuffer{
+					txBuffer:   txBuffer{make(map[BucketID]*bucketBuffer)},
+					bufVersion: 0,
+				},
+				buckets: make(map[BucketID]*bolt.Bucket),
+				txWg:    new(sync.WaitGroup),
+				txMu:    new(sync.RWMutex),
+			},
+		},
+		txReadBufferCache: txReadBufferCache{
+			mu:         sync.Mutex{},
+			bufVersion: 0,
+			buf:        nil,
+		},
+
+		stopc: make(chan struct{}),
+		donec: make(chan struct{}),
+
+		lg: bcfg.Logger,
+	}
+
+	b.batchTx = newBatchTxBuffered(b)
+	// We set it after newBatchTxBuffered to skip the 'empty' commit.
+	b.hooks = bcfg.Hooks
+
+	go b.run()
+	return b
+}
+
+// BatchTx returns the current batch tx in coalescer. The tx can be used for read and
+// write operations. The write result can be retrieved within the same tx immediately.
+// The write result is isolated with other txs until the current one get committed.
+func (b *backend) BatchTx() BatchTx {
+	return b.batchTx
+}
+
+func (b *backend) SetTxPostLockInsideApplyHook(hook func()) {
+	// It needs to lock the batchTx, because the periodic commit
+	// may be accessing the txPostLockInsideApplyHook at the moment.
+	b.batchTx.lock()
+	defer b.batchTx.Unlock()
+	b.txPostLockInsideApplyHook = hook
+}
+
+func (b *backend) ReadTx() ReadTx { return b.readTx }
+
+// ConcurrentReadTx creates and returns a new ReadTx, which:
+// A) creates and keeps a copy of backend.readTx.txReadBuffer,
+// B) references the boltdb read Tx (and its bucket cache) of current batch interval.
+func (b *backend) ConcurrentReadTx() ReadTx {
+	b.readTx.RLock()
+	defer b.readTx.RUnlock()
+	// prevent boltdb read Tx from been rolled back until store read Tx is done. Needs to be called when holding readTx.RLock().
+	b.readTx.txWg.Add(1)
+
+	// TODO: might want to copy the read buffer lazily - create copy when A) end of a write transaction B) end of a batch interval.
+
+	// inspect/update cache recency iff there's no ongoing update to the cache
+	// this falls through if there's no cache update
+
+	// by this line, "ConcurrentReadTx" code path is already protected against concurrent "writeback" operations
+	// which requires write lock to update "readTx.baseReadTx.buf".
+	// Which means setting "buf *txReadBuffer" with "readTx.buf.unsafeCopy()" is guaranteed to be up-to-date,
+	// whereas "txReadBufferCache.buf" may be stale from concurrent "writeback" operations.
+	// We only update "txReadBufferCache.buf" if we know "buf *txReadBuffer" is up-to-date.
+	// The update to "txReadBufferCache.buf" will benefit the following "ConcurrentReadTx" creation
+	// by avoiding copying "readTx.baseReadTx.buf".
+	b.txReadBufferCache.mu.Lock()
+
+	curCache := b.txReadBufferCache.buf
+	curCacheVer := b.txReadBufferCache.bufVersion
+	curBufVer := b.readTx.buf.bufVersion
+
+	isEmptyCache := curCache == nil
+	isStaleCache := curCacheVer != curBufVer
+
+	var buf *txReadBuffer
+	switch {
+	case isEmptyCache:
+		// perform safe copy of buffer while holding "b.txReadBufferCache.mu.Lock"
+		// this is only supposed to run once so there won't be much overhead
+		curBuf := b.readTx.buf.unsafeCopy()
+		buf = &curBuf
+	case isStaleCache:
+		// to maximize the concurrency, try unsafe copy of buffer
+		// release the lock while copying buffer -- cache may become stale again and
+		// get overwritten by someone else.
+		// therefore, we need to check the readTx buffer version again
+		b.txReadBufferCache.mu.Unlock()
+		curBuf := b.readTx.buf.unsafeCopy()
+		b.txReadBufferCache.mu.Lock()
+		buf = &curBuf
+	default:
+		// neither empty nor stale cache, just use the current buffer
+		buf = curCache
+	}
+	// txReadBufferCache.bufVersion can be modified when we doing an unsafeCopy()
+	// as a result, curCacheVer could be no longer the same as
+	// txReadBufferCache.bufVersion
+	// if !isEmptyCache && curCacheVer != b.txReadBufferCache.bufVersion
+	// then the cache became stale while copying "readTx.baseReadTx.buf".
+	// It is safe to not update "txReadBufferCache.buf", because the next following
+	// "ConcurrentReadTx" creation will trigger a new "readTx.baseReadTx.buf" copy
+	// and "buf" is still used for the current "concurrentReadTx.baseReadTx.buf".
+	if isEmptyCache || curCacheVer == b.txReadBufferCache.bufVersion {
+		// continue if the cache is never set or no one has modified the cache
+		b.txReadBufferCache.buf = buf
+		b.txReadBufferCache.bufVersion = curBufVer
+	}
+
+	b.txReadBufferCache.mu.Unlock()
+
+	// concurrentReadTx is not supposed to write to its txReadBuffer
+	return &concurrentReadTx{
+		baseReadTx: baseReadTx{
+			buf:     *buf,
+			txMu:    b.readTx.txMu,
+			tx:      b.readTx.tx,
+			buckets: b.readTx.buckets,
+			txWg:    b.readTx.txWg,
+		},
+	}
+}
+
+// ForceCommit forces the current batching tx to commit.
+func (b *backend) ForceCommit() {
+	b.batchTx.Commit()
+}
+
+func (b *backend) Snapshot() Snapshot {
+	b.batchTx.Commit()
+
+	b.mu.RLock()
+	defer b.mu.RUnlock()
+	tx, err := b.db.Begin(false)
+	if err != nil {
+		b.lg.Fatal("failed to begin tx", zap.Error(err))
+	}
+
+	stopc, donec := make(chan struct{}), make(chan struct{})
+	dbBytes := tx.Size()
+	go func() {
+		defer close(donec)
+		// sendRateBytes is based on transferring snapshot data over a 1 gigabit/s connection
+		// assuming a min tcp throughput of 100MB/s.
+		var sendRateBytes int64 = 100 * 1024 * 1024
+		warningTimeout := time.Duration(int64((float64(dbBytes) / float64(sendRateBytes)) * float64(time.Second)))
+		if warningTimeout < minSnapshotWarningTimeout {
+			warningTimeout = minSnapshotWarningTimeout
+		}
+		start := time.Now()
+		ticker := time.NewTicker(warningTimeout)
+		defer ticker.Stop()
+		for {
+			select {
+			case <-ticker.C:
+				b.lg.Warn(
+					"snapshotting taking too long to transfer",
+					zap.Duration("taking", time.Since(start)),
+					zap.Int64("bytes", dbBytes),
+					zap.String("size", humanize.Bytes(uint64(dbBytes))),
+				)
+
+			case <-stopc:
+				snapshotTransferSec.Observe(time.Since(start).Seconds())
+				return
+			}
+		}
+	}()
+
+	return &snapshot{tx, stopc, donec}
+}
+
+func (b *backend) Hash(ignores func(bucketName, keyName []byte) bool) (uint32, error) {
+	h := crc32.New(crc32.MakeTable(crc32.Castagnoli))
+
+	b.mu.RLock()
+	defer b.mu.RUnlock()
+	err := b.db.View(func(tx *bolt.Tx) error {
+		c := tx.Cursor()
+		for next, _ := c.First(); next != nil; next, _ = c.Next() {
+			b := tx.Bucket(next)
+			if b == nil {
+				return fmt.Errorf("cannot get hash of bucket %s", next)
+			}
+			h.Write(next)
+			b.ForEach(func(k, v []byte) error {
+				if ignores != nil && !ignores(next, k) {
+					h.Write(k)
+					h.Write(v)
+				}
+				return nil
+			})
+		}
+		return nil
+	})
+	if err != nil {
+		return 0, err
+	}
+
+	return h.Sum32(), nil
+}
+
+func (b *backend) Size() int64 {
+	return atomic.LoadInt64(&b.size)
+}
+
+func (b *backend) SizeInUse() int64 {
+	return atomic.LoadInt64(&b.sizeInUse)
+}
+
+func (b *backend) run() {
+	defer close(b.donec)
+	t := time.NewTimer(b.batchInterval)
+	defer t.Stop()
+	for {
+		select {
+		case <-t.C:
+		case <-b.stopc:
+			b.batchTx.CommitAndStop()
+			return
+		}
+		if b.batchTx.safePending() != 0 {
+			b.batchTx.Commit()
+		}
+		t.Reset(b.batchInterval)
+	}
+}
+
+func (b *backend) Close() error {
+	close(b.stopc)
+	<-b.donec
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	return b.db.Close()
+}
+
+// Commits returns total number of commits since start
+func (b *backend) Commits() int64 {
+	return atomic.LoadInt64(&b.commits)
+}
+
+func (b *backend) Defrag() error {
+	return b.defrag()
+}
+
+func (b *backend) defrag() error {
+	verify.Assert(b.lg != nil, "the logger should not be nil")
+	now := time.Now()
+	isDefragActive.Set(1)
+	defer isDefragActive.Set(0)
+
+	// TODO: make this non-blocking?
+	// lock batchTx to ensure nobody is using previous tx, and then
+	// close previous ongoing tx.
+	b.batchTx.LockOutsideApply()
+	defer b.batchTx.Unlock()
+
+	// lock database after lock tx to avoid deadlock.
+	b.mu.Lock()
+	defer b.mu.Unlock()
+
+	// block concurrent read requests while resetting tx
+	b.readTx.Lock()
+	defer b.readTx.Unlock()
+
+	// Create a temporary file to ensure we start with a clean slate.
+	// Snapshotter.cleanupSnapdir cleans up any of these that are found during startup.
+	dir := filepath.Dir(b.db.Path())
+	temp, err := os.CreateTemp(dir, "db.tmp.*")
+	if err != nil {
+		return err
+	}
+
+	options := bolt.Options{}
+	if boltOpenOptions != nil {
+		options = *boltOpenOptions
+	}
+	options.OpenFile = func(_ string, _ int, _ os.FileMode) (file *os.File, err error) {
+		// gofail: var defragOpenFileError string
+		// return nil, fmt.Errorf(defragOpenFileError)
+		return temp, nil
+	}
+	// Don't load tmp db into memory regardless of opening options
+	options.Mlock = false
+	tdbp := temp.Name()
+	tmpdb, err := bolt.Open(tdbp, 0o600, &options)
+	if err != nil {
+		temp.Close()
+		if rmErr := os.Remove(temp.Name()); rmErr != nil {
+			b.lg.Error(
+				"failed to remove temporary file",
+				zap.String("path", temp.Name()),
+				zap.Error(rmErr),
+			)
+		}
+
+		return err
+	}
+
+	dbp := b.db.Path()
+	size1, sizeInUse1 := b.Size(), b.SizeInUse()
+	b.lg.Info(
+		"defragmenting",
+		zap.String("path", dbp),
+		zap.Int64("current-db-size-bytes", size1),
+		zap.String("current-db-size", humanize.Bytes(uint64(size1))),
+		zap.Int64("current-db-size-in-use-bytes", sizeInUse1),
+		zap.String("current-db-size-in-use", humanize.Bytes(uint64(sizeInUse1))),
+	)
+
+	defer func() {
+		// NOTE: We should exit as soon as possible because that tx
+		// might be closed. The inflight request might use invalid
+		// tx and then panic as well. The real panic reason might be
+		// shadowed by new panic. So, we should fatal here with lock.
+		if rerr := recover(); rerr != nil {
+			b.lg.Fatal("unexpected panic during defrag", zap.Any("panic", rerr))
+		}
+	}()
+
+	// Commit/stop and then reset current transactions (including the readTx)
+	b.batchTx.unsafeCommit(true)
+	b.batchTx.tx = nil
+
+	// gofail: var defragBeforeCopy struct{}
+	err = defragdb(b.db, tmpdb, defragLimit)
+	if err != nil {
+		tmpdb.Close()
+		if rmErr := os.RemoveAll(tmpdb.Path()); rmErr != nil {
+			b.lg.Error("failed to remove db.tmp after defragmentation completed", zap.Error(rmErr))
+		}
+
+		// restore the bbolt transactions if defragmentation fails
+		b.batchTx.tx = b.unsafeBegin(true)
+		b.readTx.tx = b.unsafeBegin(false)
+
+		return err
+	}
+
+	err = b.db.Close()
+	if err != nil {
+		b.lg.Fatal("failed to close database", zap.Error(err))
+	}
+	err = tmpdb.Close()
+	if err != nil {
+		b.lg.Fatal("failed to close tmp database", zap.Error(err))
+	}
+	// gofail: var defragBeforeRename struct{}
+	err = os.Rename(tdbp, dbp)
+	if err != nil {
+		b.lg.Fatal("failed to rename tmp database", zap.Error(err))
+	}
+
+	b.db, err = bolt.Open(dbp, 0o600, b.bopts)
+	if err != nil {
+		b.lg.Fatal("failed to open database", zap.String("path", dbp), zap.Error(err))
+	}
+	b.batchTx.tx = b.unsafeBegin(true)
+
+	b.readTx.reset()
+	b.readTx.tx = b.unsafeBegin(false)
+
+	size := b.readTx.tx.Size()
+	db := b.readTx.tx.DB()
+	atomic.StoreInt64(&b.size, size)
+	atomic.StoreInt64(&b.sizeInUse, size-(int64(db.Stats().FreePageN)*int64(db.Info().PageSize)))
+
+	took := time.Since(now)
+	defragSec.Observe(took.Seconds())
+
+	size2, sizeInUse2 := b.Size(), b.SizeInUse()
+	b.lg.Info(
+		"finished defragmenting directory",
+		zap.String("path", dbp),
+		zap.Int64("current-db-size-bytes-diff", size2-size1),
+		zap.Int64("current-db-size-bytes", size2),
+		zap.String("current-db-size", humanize.Bytes(uint64(size2))),
+		zap.Int64("current-db-size-in-use-bytes-diff", sizeInUse2-sizeInUse1),
+		zap.Int64("current-db-size-in-use-bytes", sizeInUse2),
+		zap.String("current-db-size-in-use", humanize.Bytes(uint64(sizeInUse2))),
+		zap.Duration("took", took),
+	)
+	return nil
+}
+
+func defragdb(odb, tmpdb *bolt.DB, limit int) error {
+	// gofail: var defragdbFail string
+	// return fmt.Errorf(defragdbFail)
+
+	// open a tx on tmpdb for writes
+	tmptx, err := tmpdb.Begin(true)
+	if err != nil {
+		return err
+	}
+	defer func() {
+		if err != nil {
+			tmptx.Rollback()
+		}
+	}()
+
+	// open a tx on old db for read
+	tx, err := odb.Begin(false)
+	if err != nil {
+		return err
+	}
+	defer tx.Rollback()
+
+	c := tx.Cursor()
+
+	count := 0
+	for next, _ := c.First(); next != nil; next, _ = c.Next() {
+		b := tx.Bucket(next)
+		if b == nil {
+			return fmt.Errorf("backend: cannot defrag bucket %s", next)
+		}
+
+		tmpb, berr := tmptx.CreateBucketIfNotExists(next)
+		if berr != nil {
+			return berr
+		}
+		tmpb.FillPercent = 0.9 // for bucket2seq write in for each
+
+		if err = b.ForEach(func(k, v []byte) error {
+			count++
+			if count > limit {
+				err = tmptx.Commit()
+				if err != nil {
+					return err
+				}
+				tmptx, err = tmpdb.Begin(true)
+				if err != nil {
+					return err
+				}
+				tmpb = tmptx.Bucket(next)
+				tmpb.FillPercent = 0.9 // for bucket2seq write in for each
+
+				count = 0
+			}
+			return tmpb.Put(k, v)
+		}); err != nil {
+			return err
+		}
+	}
+
+	return tmptx.Commit()
+}
+
+func (b *backend) begin(write bool) *bolt.Tx {
+	b.mu.RLock()
+	tx := b.unsafeBegin(write)
+	b.mu.RUnlock()
+
+	size := tx.Size()
+	db := tx.DB()
+	stats := db.Stats()
+	atomic.StoreInt64(&b.size, size)
+	atomic.StoreInt64(&b.sizeInUse, size-(int64(stats.FreePageN)*int64(db.Info().PageSize)))
+	atomic.StoreInt64(&b.openReadTxN, int64(stats.OpenTxN))
+
+	return tx
+}
+
+func (b *backend) unsafeBegin(write bool) *bolt.Tx {
+	// gofail: var beforeStartDBTxn struct{}
+	tx, err := b.db.Begin(write)
+	// gofail: var afterStartDBTxn struct{}
+	if err != nil {
+		b.lg.Fatal("failed to begin tx", zap.Error(err))
+	}
+	return tx
+}
+
+func (b *backend) OpenReadTxN() int64 {
+	return atomic.LoadInt64(&b.openReadTxN)
+}
+
+type snapshot struct {
+	*bolt.Tx
+	stopc chan struct{}
+	donec chan struct{}
+}
+
+func (s *snapshot) Close() error {
+	close(s.stopc)
+	<-s.donec
+	return s.Tx.Rollback()
+}
+
+func newBoltLoggerZap(bcfg BackendConfig) bolt.Logger {
+	lg := bcfg.Logger.Named("bbolt")
+	return &zapBoltLogger{lg.WithOptions(zap.AddCallerSkip(1)).Sugar()}
+}
+
+type zapBoltLogger struct {
+	*zap.SugaredLogger
+}
+
+func (zl *zapBoltLogger) Warning(args ...any) {
+	zl.SugaredLogger.Warn(args...)
+}
+
+func (zl *zapBoltLogger) Warningf(format string, args ...any) {
+	zl.SugaredLogger.Warnf(format, args...)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/backend/batch_tx.go b/vendor/go.etcd.io/etcd/server/v3/storage/backend/batch_tx.go
new file mode 100644
index 0000000..5af557c
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/backend/batch_tx.go
@@ -0,0 +1,406 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package backend
+
+import (
+	"bytes"
+	"errors"
+	"math"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"go.uber.org/zap"
+
+	bolt "go.etcd.io/bbolt"
+	bolterrors "go.etcd.io/bbolt/errors"
+)
+
+type BucketID int
+
+type Bucket interface {
+	// ID returns a unique identifier of a bucket.
+	// The id must NOT be persisted and can be used as lightweight identificator
+	// in the in-memory maps.
+	ID() BucketID
+	Name() []byte
+	// String implements Stringer (human readable name).
+	String() string
+
+	// IsSafeRangeBucket is a hack to avoid inadvertently reading duplicate keys;
+	// overwrites on a bucket should only fetch with limit=1, but safeRangeBucket
+	// is known to never overwrite any key so range is safe.
+	IsSafeRangeBucket() bool
+}
+
+type BatchTx interface {
+	Lock()
+	Unlock()
+	// Commit commits a previous tx and begins a new writable one.
+	Commit()
+	// CommitAndStop commits the previous tx and does not create a new one.
+	CommitAndStop()
+	LockInsideApply()
+	LockOutsideApply()
+	UnsafeReadWriter
+}
+
+type UnsafeReadWriter interface {
+	UnsafeReader
+	UnsafeWriter
+}
+
+type UnsafeWriter interface {
+	UnsafeCreateBucket(bucket Bucket)
+	UnsafeDeleteBucket(bucket Bucket)
+	UnsafePut(bucket Bucket, key []byte, value []byte)
+	UnsafeSeqPut(bucket Bucket, key []byte, value []byte)
+	UnsafeDelete(bucket Bucket, key []byte)
+}
+
+type batchTx struct {
+	sync.Mutex
+	tx      *bolt.Tx
+	backend *backend
+
+	pending int
+}
+
+// Lock is supposed to be called only by the unit test.
+func (t *batchTx) Lock() {
+	ValidateCalledInsideUnittest(t.backend.lg)
+	t.lock()
+}
+
+func (t *batchTx) lock() {
+	t.Mutex.Lock()
+}
+
+func (t *batchTx) LockInsideApply() {
+	t.lock()
+	if t.backend.txPostLockInsideApplyHook != nil {
+		// The callers of some methods (i.e., (*RaftCluster).AddMember)
+		// can be coming from both InsideApply and OutsideApply, but the
+		// callers from OutsideApply will have a nil txPostLockInsideApplyHook.
+		// So we should check the txPostLockInsideApplyHook before validating
+		// the callstack.
+		ValidateCalledInsideApply(t.backend.lg)
+		t.backend.txPostLockInsideApplyHook()
+	}
+}
+
+func (t *batchTx) LockOutsideApply() {
+	ValidateCalledOutSideApply(t.backend.lg)
+	t.lock()
+}
+
+func (t *batchTx) Unlock() {
+	if t.pending >= t.backend.batchLimit {
+		t.commit(false)
+	}
+	t.Mutex.Unlock()
+}
+
+func (t *batchTx) UnsafeCreateBucket(bucket Bucket) {
+	if _, err := t.tx.CreateBucketIfNotExists(bucket.Name()); err != nil {
+		t.backend.lg.Fatal(
+			"failed to create a bucket",
+			zap.Stringer("bucket-name", bucket),
+			zap.Error(err),
+		)
+	}
+	t.pending++
+}
+
+func (t *batchTx) UnsafeDeleteBucket(bucket Bucket) {
+	err := t.tx.DeleteBucket(bucket.Name())
+	if err != nil && !errors.Is(err, bolterrors.ErrBucketNotFound) {
+		t.backend.lg.Fatal(
+			"failed to delete a bucket",
+			zap.Stringer("bucket-name", bucket),
+			zap.Error(err),
+		)
+	}
+	t.pending++
+}
+
+// UnsafePut must be called holding the lock on the tx.
+func (t *batchTx) UnsafePut(bucket Bucket, key []byte, value []byte) {
+	t.unsafePut(bucket, key, value, false)
+}
+
+// UnsafeSeqPut must be called holding the lock on the tx.
+func (t *batchTx) UnsafeSeqPut(bucket Bucket, key []byte, value []byte) {
+	t.unsafePut(bucket, key, value, true)
+}
+
+func (t *batchTx) unsafePut(bucketType Bucket, key []byte, value []byte, seq bool) {
+	bucket := t.tx.Bucket(bucketType.Name())
+	if bucket == nil {
+		t.backend.lg.Fatal(
+			"failed to find a bucket",
+			zap.Stringer("bucket-name", bucketType),
+			zap.Stack("stack"),
+		)
+	}
+	if seq {
+		// it is useful to increase fill percent when the workloads are mostly append-only.
+		// this can delay the page split and reduce space usage.
+		bucket.FillPercent = 0.9
+	}
+	if err := bucket.Put(key, value); err != nil {
+		t.backend.lg.Fatal(
+			"failed to write to a bucket",
+			zap.Stringer("bucket-name", bucketType),
+			zap.Error(err),
+		)
+	}
+	t.pending++
+}
+
+// UnsafeRange must be called holding the lock on the tx.
+func (t *batchTx) UnsafeRange(bucketType Bucket, key, endKey []byte, limit int64) ([][]byte, [][]byte) {
+	bucket := t.tx.Bucket(bucketType.Name())
+	if bucket == nil {
+		t.backend.lg.Fatal(
+			"failed to find a bucket",
+			zap.Stringer("bucket-name", bucketType),
+			zap.Stack("stack"),
+		)
+	}
+	return unsafeRange(bucket.Cursor(), key, endKey, limit)
+}
+
+func unsafeRange(c *bolt.Cursor, key, endKey []byte, limit int64) (keys [][]byte, vs [][]byte) {
+	if limit <= 0 {
+		limit = math.MaxInt64
+	}
+	var isMatch func(b []byte) bool
+	if len(endKey) > 0 {
+		isMatch = func(b []byte) bool { return bytes.Compare(b, endKey) < 0 }
+	} else {
+		isMatch = func(b []byte) bool { return bytes.Equal(b, key) }
+		limit = 1
+	}
+
+	for ck, cv := c.Seek(key); ck != nil && isMatch(ck); ck, cv = c.Next() {
+		vs = append(vs, cv)
+		keys = append(keys, ck)
+		if limit == int64(len(keys)) {
+			break
+		}
+	}
+	return keys, vs
+}
+
+// UnsafeDelete must be called holding the lock on the tx.
+func (t *batchTx) UnsafeDelete(bucketType Bucket, key []byte) {
+	bucket := t.tx.Bucket(bucketType.Name())
+	if bucket == nil {
+		t.backend.lg.Fatal(
+			"failed to find a bucket",
+			zap.Stringer("bucket-name", bucketType),
+			zap.Stack("stack"),
+		)
+	}
+	err := bucket.Delete(key)
+	if err != nil {
+		t.backend.lg.Fatal(
+			"failed to delete a key",
+			zap.Stringer("bucket-name", bucketType),
+			zap.Error(err),
+		)
+	}
+	t.pending++
+}
+
+// UnsafeForEach must be called holding the lock on the tx.
+func (t *batchTx) UnsafeForEach(bucket Bucket, visitor func(k, v []byte) error) error {
+	return unsafeForEach(t.tx, bucket, visitor)
+}
+
+func unsafeForEach(tx *bolt.Tx, bucket Bucket, visitor func(k, v []byte) error) error {
+	if b := tx.Bucket(bucket.Name()); b != nil {
+		return b.ForEach(visitor)
+	}
+	return nil
+}
+
+// Commit commits a previous tx and begins a new writable one.
+func (t *batchTx) Commit() {
+	t.lock()
+	t.commit(false)
+	t.Unlock()
+}
+
+// CommitAndStop commits the previous tx and does not create a new one.
+func (t *batchTx) CommitAndStop() {
+	t.lock()
+	t.commit(true)
+	t.Unlock()
+}
+
+func (t *batchTx) safePending() int {
+	t.Mutex.Lock()
+	defer t.Mutex.Unlock()
+	return t.pending
+}
+
+func (t *batchTx) commit(stop bool) {
+	// commit the last tx
+	if t.tx != nil {
+		if t.pending == 0 && !stop {
+			return
+		}
+
+		start := time.Now()
+
+		// gofail: var beforeCommit struct{}
+		err := t.tx.Commit()
+		// gofail: var afterCommit struct{}
+
+		rebalanceSec.Observe(t.tx.Stats().RebalanceTime.Seconds())
+		spillSec.Observe(t.tx.Stats().SpillTime.Seconds())
+		writeSec.Observe(t.tx.Stats().WriteTime.Seconds())
+		commitSec.Observe(time.Since(start).Seconds())
+		atomic.AddInt64(&t.backend.commits, 1)
+
+		t.pending = 0
+		if err != nil {
+			t.backend.lg.Fatal("failed to commit tx", zap.Error(err))
+		}
+	}
+	if !stop {
+		t.tx = t.backend.begin(true)
+	}
+}
+
+type batchTxBuffered struct {
+	batchTx
+	buf                     txWriteBuffer
+	pendingDeleteOperations int
+}
+
+func newBatchTxBuffered(backend *backend) *batchTxBuffered {
+	tx := &batchTxBuffered{
+		batchTx: batchTx{backend: backend},
+		buf: txWriteBuffer{
+			txBuffer:   txBuffer{make(map[BucketID]*bucketBuffer)},
+			bucket2seq: make(map[BucketID]bool),
+		},
+	}
+	tx.Commit()
+	return tx
+}
+
+func (t *batchTxBuffered) Unlock() {
+	if t.pending != 0 {
+		t.backend.readTx.Lock() // blocks txReadBuffer for writing.
+		// gofail: var beforeWritebackBuf struct{}
+		t.buf.writeback(&t.backend.readTx.buf)
+		// gofail: var afterWritebackBuf struct{}
+		t.backend.readTx.Unlock()
+		// We commit the transaction when the number of pending operations
+		// reaches the configured limit(batchLimit) to prevent it from
+		// becoming excessively large.
+		//
+		// But we also need to commit the transaction immediately if there
+		// is any pending deleting operation, otherwise etcd might run into
+		// a situation that it haven't finished committing the data into backend
+		// storage (note: etcd periodically commits the bbolt transactions
+		// instead of on each request) when it applies next request. Accordingly,
+		// etcd may still read the stale data from bbolt when processing next
+		// request. So it breaks the linearizability.
+		//
+		// Note we don't need to commit the transaction for put requests if
+		// it doesn't exceed the batch limit, because there is a buffer on top
+		// of the bbolt. Each time when etcd reads data from backend storage,
+		// it will read data from both bbolt and the buffer. But there is no
+		// such a buffer for delete requests.
+		//
+		// Please also refer to
+		// https://github.com/etcd-io/etcd/pull/17119#issuecomment-1857547158
+		if t.pending >= t.backend.batchLimit || t.pendingDeleteOperations > 0 {
+			t.commit(false)
+		}
+	}
+	t.batchTx.Unlock()
+}
+
+func (t *batchTxBuffered) Commit() {
+	t.lock()
+	t.commit(false)
+	t.Unlock()
+}
+
+func (t *batchTxBuffered) CommitAndStop() {
+	t.lock()
+	t.commit(true)
+	t.Unlock()
+}
+
+func (t *batchTxBuffered) commit(stop bool) {
+	// all read txs must be closed to acquire boltdb commit rwlock
+	t.backend.readTx.Lock()
+	t.unsafeCommit(stop)
+	t.backend.readTx.Unlock()
+}
+
+func (t *batchTxBuffered) unsafeCommit(stop bool) {
+	if t.backend.hooks != nil {
+		// gofail: var commitBeforePreCommitHook struct{}
+		t.backend.hooks.OnPreCommitUnsafe(t)
+		// gofail: var commitAfterPreCommitHook struct{}
+	}
+
+	if t.backend.readTx.tx != nil {
+		// wait all store read transactions using the current boltdb tx to finish,
+		// then close the boltdb tx
+		go func(tx *bolt.Tx, wg *sync.WaitGroup) {
+			wg.Wait()
+			if err := tx.Rollback(); err != nil {
+				t.backend.lg.Fatal("failed to rollback tx", zap.Error(err))
+			}
+		}(t.backend.readTx.tx, t.backend.readTx.txWg)
+		t.backend.readTx.reset()
+	}
+
+	t.batchTx.commit(stop)
+	t.pendingDeleteOperations = 0
+
+	if !stop {
+		t.backend.readTx.tx = t.backend.begin(false)
+	}
+}
+
+func (t *batchTxBuffered) UnsafePut(bucket Bucket, key []byte, value []byte) {
+	t.batchTx.UnsafePut(bucket, key, value)
+	t.buf.put(bucket, key, value)
+}
+
+func (t *batchTxBuffered) UnsafeSeqPut(bucket Bucket, key []byte, value []byte) {
+	t.batchTx.UnsafeSeqPut(bucket, key, value)
+	t.buf.putSeq(bucket, key, value)
+}
+
+func (t *batchTxBuffered) UnsafeDelete(bucketType Bucket, key []byte) {
+	t.batchTx.UnsafeDelete(bucketType, key)
+	t.pendingDeleteOperations++
+}
+
+func (t *batchTxBuffered) UnsafeDeleteBucket(bucket Bucket) {
+	t.batchTx.UnsafeDeleteBucket(bucket)
+	t.pendingDeleteOperations++
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/backend/config_default.go b/vendor/go.etcd.io/etcd/server/v3/storage/backend/config_default.go
new file mode 100644
index 0000000..fd57c7c
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/backend/config_default.go
@@ -0,0 +1,23 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build !linux && !windows
+
+package backend
+
+import bolt "go.etcd.io/bbolt"
+
+var boltOpenOptions *bolt.Options
+
+func (bcfg *BackendConfig) mmapSize() int { return int(bcfg.MmapSize) }
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/backend/config_linux.go b/vendor/go.etcd.io/etcd/server/v3/storage/backend/config_linux.go
new file mode 100644
index 0000000..f712671
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/backend/config_linux.go
@@ -0,0 +1,34 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package backend
+
+import (
+	"syscall"
+
+	bolt "go.etcd.io/bbolt"
+)
+
+// syscall.MAP_POPULATE on linux 2.6.23+ does sequential read-ahead
+// which can speed up entire-database read with boltdb. We want to
+// enable MAP_POPULATE for faster key-value store recovery in storage
+// package. If your kernel version is lower than 2.6.23
+// (https://github.com/torvalds/linux/releases/tag/v2.6.23), mmap might
+// silently ignore this flag. Please update your kernel to prevent this.
+var boltOpenOptions = &bolt.Options{
+	MmapFlags:      syscall.MAP_POPULATE,
+	NoFreelistSync: true,
+}
+
+func (bcfg *BackendConfig) mmapSize() int { return int(bcfg.MmapSize) }
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/backend/config_windows.go b/vendor/go.etcd.io/etcd/server/v3/storage/backend/config_windows.go
new file mode 100644
index 0000000..7bb42f3
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/backend/config_windows.go
@@ -0,0 +1,26 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build windows
+
+package backend
+
+import bolt "go.etcd.io/bbolt"
+
+var boltOpenOptions *bolt.Options = nil
+
+// setting mmap size != 0 on windows will allocate the entire
+// mmap size for the file, instead of growing it. So, force 0.
+
+func (bcfg *BackendConfig) mmapSize() int { return 0 }
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/backend/doc.go b/vendor/go.etcd.io/etcd/server/v3/storage/backend/doc.go
new file mode 100644
index 0000000..9cc42fa
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/backend/doc.go
@@ -0,0 +1,16 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package backend defines a standard interface for etcd's backend MVCC storage.
+package backend
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/backend/hooks.go b/vendor/go.etcd.io/etcd/server/v3/storage/backend/hooks.go
new file mode 100644
index 0000000..817d0c5
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/backend/hooks.go
@@ -0,0 +1,36 @@
+// Copyright 2021 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package backend
+
+type HookFunc func(tx UnsafeReadWriter)
+
+// Hooks allow to add additional logic executed during transaction lifetime.
+type Hooks interface {
+	// OnPreCommitUnsafe is executed before Commit of transactions.
+	// The given transaction is already locked.
+	OnPreCommitUnsafe(tx UnsafeReadWriter)
+}
+
+type hooks struct {
+	onPreCommitUnsafe HookFunc
+}
+
+func (h hooks) OnPreCommitUnsafe(tx UnsafeReadWriter) {
+	h.onPreCommitUnsafe(tx)
+}
+
+func NewHooks(onPreCommitUnsafe HookFunc) Hooks {
+	return hooks{onPreCommitUnsafe: onPreCommitUnsafe}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/backend/metrics.go b/vendor/go.etcd.io/etcd/server/v3/storage/backend/metrics.go
new file mode 100644
index 0000000..9d58c00
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/backend/metrics.go
@@ -0,0 +1,103 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package backend
+
+import "github.com/prometheus/client_golang/prometheus"
+
+var (
+	commitSec = prometheus.NewHistogram(prometheus.HistogramOpts{
+		Namespace: "etcd",
+		Subsystem: "disk",
+		Name:      "backend_commit_duration_seconds",
+		Help:      "The latency distributions of commit called by backend.",
+
+		// lowest bucket start of upper bound 0.001 sec (1 ms) with factor 2
+		// highest bucket start of 0.001 sec * 2^13 == 8.192 sec
+		Buckets: prometheus.ExponentialBuckets(0.001, 2, 14),
+	})
+
+	rebalanceSec = prometheus.NewHistogram(prometheus.HistogramOpts{
+		Namespace: "etcd_debugging",
+		Subsystem: "disk",
+		Name:      "backend_commit_rebalance_duration_seconds",
+		Help:      "The latency distributions of commit.rebalance called by bboltdb backend.",
+
+		// lowest bucket start of upper bound 0.001 sec (1 ms) with factor 2
+		// highest bucket start of 0.001 sec * 2^13 == 8.192 sec
+		Buckets: prometheus.ExponentialBuckets(0.001, 2, 14),
+	})
+
+	spillSec = prometheus.NewHistogram(prometheus.HistogramOpts{
+		Namespace: "etcd_debugging",
+		Subsystem: "disk",
+		Name:      "backend_commit_spill_duration_seconds",
+		Help:      "The latency distributions of commit.spill called by bboltdb backend.",
+
+		// lowest bucket start of upper bound 0.001 sec (1 ms) with factor 2
+		// highest bucket start of 0.001 sec * 2^13 == 8.192 sec
+		Buckets: prometheus.ExponentialBuckets(0.001, 2, 14),
+	})
+
+	writeSec = prometheus.NewHistogram(prometheus.HistogramOpts{
+		Namespace: "etcd_debugging",
+		Subsystem: "disk",
+		Name:      "backend_commit_write_duration_seconds",
+		Help:      "The latency distributions of commit.write called by bboltdb backend.",
+
+		// lowest bucket start of upper bound 0.001 sec (1 ms) with factor 2
+		// highest bucket start of 0.001 sec * 2^13 == 8.192 sec
+		Buckets: prometheus.ExponentialBuckets(0.001, 2, 14),
+	})
+
+	defragSec = prometheus.NewHistogram(prometheus.HistogramOpts{
+		Namespace: "etcd",
+		Subsystem: "disk",
+		Name:      "backend_defrag_duration_seconds",
+		Help:      "The latency distribution of backend defragmentation.",
+
+		// 100 MB usually takes 1 sec, so start with 10 MB of 100 ms
+		// lowest bucket start of upper bound 0.1 sec (100 ms) with factor 2
+		// highest bucket start of 0.1 sec * 2^12 == 409.6 sec
+		Buckets: prometheus.ExponentialBuckets(.1, 2, 13),
+	})
+
+	snapshotTransferSec = prometheus.NewHistogram(prometheus.HistogramOpts{
+		Namespace: "etcd",
+		Subsystem: "disk",
+		Name:      "backend_snapshot_duration_seconds",
+		Help:      "The latency distribution of backend snapshots.",
+
+		// lowest bucket start of upper bound 0.01 sec (10 ms) with factor 2
+		// highest bucket start of 0.01 sec * 2^16 == 655.36 sec
+		Buckets: prometheus.ExponentialBuckets(.01, 2, 17),
+	})
+
+	isDefragActive = prometheus.NewGauge(prometheus.GaugeOpts{
+		Namespace: "etcd",
+		Subsystem: "disk",
+		Name:      "defrag_inflight",
+		Help:      "Whether or not defrag is active on the member. 1 means active, 0 means not.",
+	})
+)
+
+func init() {
+	prometheus.MustRegister(commitSec)
+	prometheus.MustRegister(rebalanceSec)
+	prometheus.MustRegister(spillSec)
+	prometheus.MustRegister(writeSec)
+	prometheus.MustRegister(defragSec)
+	prometheus.MustRegister(snapshotTransferSec)
+	prometheus.MustRegister(isDefragActive)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/backend/read_tx.go b/vendor/go.etcd.io/etcd/server/v3/storage/backend/read_tx.go
new file mode 100644
index 0000000..4ca2621
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/backend/read_tx.go
@@ -0,0 +1,151 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package backend
+
+import (
+	"math"
+	"sync"
+
+	bolt "go.etcd.io/bbolt"
+)
+
+// IsSafeRangeBucket is a hack to avoid inadvertently reading duplicate keys;
+// overwrites on a bucket should only fetch with limit=1, but IsSafeRangeBucket
+// is known to never overwrite any key so range is safe.
+
+type ReadTx interface {
+	RLock()
+	RUnlock()
+	UnsafeReader
+}
+
+type UnsafeReader interface {
+	UnsafeRange(bucket Bucket, key, endKey []byte, limit int64) (keys [][]byte, vals [][]byte)
+	UnsafeForEach(bucket Bucket, visitor func(k, v []byte) error) error
+}
+
+// Base type for readTx and concurrentReadTx to eliminate duplicate functions between these
+type baseReadTx struct {
+	// mu protects accesses to the txReadBuffer
+	mu  sync.RWMutex
+	buf txReadBuffer
+
+	// TODO: group and encapsulate {txMu, tx, buckets, txWg}, as they share the same lifecycle.
+	// txMu protects accesses to buckets and tx on Range requests.
+	txMu    *sync.RWMutex
+	tx      *bolt.Tx
+	buckets map[BucketID]*bolt.Bucket
+	// txWg protects tx from being rolled back at the end of a batch interval until all reads using this tx are done.
+	txWg *sync.WaitGroup
+}
+
+func (baseReadTx *baseReadTx) UnsafeForEach(bucket Bucket, visitor func(k, v []byte) error) error {
+	dups := make(map[string]struct{})
+	getDups := func(k, v []byte) error {
+		dups[string(k)] = struct{}{}
+		return nil
+	}
+	visitNoDup := func(k, v []byte) error {
+		if _, ok := dups[string(k)]; ok {
+			return nil
+		}
+		return visitor(k, v)
+	}
+	if err := baseReadTx.buf.ForEach(bucket, getDups); err != nil {
+		return err
+	}
+	baseReadTx.txMu.Lock()
+	err := unsafeForEach(baseReadTx.tx, bucket, visitNoDup)
+	baseReadTx.txMu.Unlock()
+	if err != nil {
+		return err
+	}
+	return baseReadTx.buf.ForEach(bucket, visitor)
+}
+
+func (baseReadTx *baseReadTx) UnsafeRange(bucketType Bucket, key, endKey []byte, limit int64) ([][]byte, [][]byte) {
+	if endKey == nil {
+		// forbid duplicates for single keys
+		limit = 1
+	}
+	if limit <= 0 {
+		limit = math.MaxInt64
+	}
+	if limit > 1 && !bucketType.IsSafeRangeBucket() {
+		panic("do not use unsafeRange on non-keys bucket")
+	}
+	keys, vals := baseReadTx.buf.Range(bucketType, key, endKey, limit)
+	if int64(len(keys)) == limit {
+		return keys, vals
+	}
+
+	// find/cache bucket
+	bn := bucketType.ID()
+	baseReadTx.txMu.RLock()
+	bucket, ok := baseReadTx.buckets[bn]
+	baseReadTx.txMu.RUnlock()
+	lockHeld := false
+	if !ok {
+		baseReadTx.txMu.Lock()
+		lockHeld = true
+		bucket = baseReadTx.tx.Bucket(bucketType.Name())
+		baseReadTx.buckets[bn] = bucket
+	}
+
+	// ignore missing bucket since may have been created in this batch
+	if bucket == nil {
+		if lockHeld {
+			baseReadTx.txMu.Unlock()
+		}
+		return keys, vals
+	}
+	if !lockHeld {
+		baseReadTx.txMu.Lock()
+	}
+	c := bucket.Cursor()
+	baseReadTx.txMu.Unlock()
+
+	k2, v2 := unsafeRange(c, key, endKey, limit-int64(len(keys)))
+	return append(k2, keys...), append(v2, vals...)
+}
+
+type readTx struct {
+	baseReadTx
+}
+
+func (rt *readTx) Lock()    { rt.mu.Lock() }
+func (rt *readTx) Unlock()  { rt.mu.Unlock() }
+func (rt *readTx) RLock()   { rt.mu.RLock() }
+func (rt *readTx) RUnlock() { rt.mu.RUnlock() }
+
+func (rt *readTx) reset() {
+	rt.buf.reset()
+	rt.buckets = make(map[BucketID]*bolt.Bucket)
+	rt.tx = nil
+	rt.txWg = new(sync.WaitGroup)
+}
+
+type concurrentReadTx struct {
+	baseReadTx
+}
+
+func (rt *concurrentReadTx) Lock()   {}
+func (rt *concurrentReadTx) Unlock() {}
+
+// RLock is no-op. concurrentReadTx does not need to be locked after it is created.
+func (rt *concurrentReadTx) RLock() {}
+
+// RUnlock signals the end of concurrentReadTx.
+func (rt *concurrentReadTx) RUnlock() { rt.txWg.Done() }
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/backend/tx_buffer.go b/vendor/go.etcd.io/etcd/server/v3/storage/backend/tx_buffer.go
new file mode 100644
index 0000000..821b300
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/backend/tx_buffer.go
@@ -0,0 +1,258 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package backend
+
+import (
+	"bytes"
+	"encoding/hex"
+	"fmt"
+	"sort"
+
+	"go.etcd.io/etcd/client/pkg/v3/verify"
+)
+
+const bucketBufferInitialSize = 512
+
+// txBuffer handles functionality shared between txWriteBuffer and txReadBuffer.
+type txBuffer struct {
+	buckets map[BucketID]*bucketBuffer
+}
+
+func (txb *txBuffer) reset() {
+	for k, v := range txb.buckets {
+		if v.used == 0 {
+			// demote
+			delete(txb.buckets, k)
+		}
+		v.used = 0
+	}
+}
+
+// txWriteBuffer buffers writes of pending updates that have not yet committed.
+type txWriteBuffer struct {
+	txBuffer
+	// Map from bucket ID into information whether this bucket is edited
+	// sequentially (i.e. keys are growing monotonically).
+	bucket2seq map[BucketID]bool
+}
+
+func (txw *txWriteBuffer) put(bucket Bucket, k, v []byte) {
+	txw.bucket2seq[bucket.ID()] = false
+	txw.putInternal(bucket, k, v)
+}
+
+func (txw *txWriteBuffer) putSeq(bucket Bucket, k, v []byte) {
+	// putSeq is only be called for the data in the Key bucket. The keys
+	// in the Key bucket should be monotonically increasing revisions.
+	verify.Verify(func() {
+		b, ok := txw.buckets[bucket.ID()]
+		if !ok || b.used == 0 {
+			return
+		}
+
+		existingMaxKey := b.buf[b.used-1].key
+		if bytes.Compare(k, existingMaxKey) <= 0 {
+			panic(fmt.Sprintf("Broke the rule of monotonically increasing, existingMaxKey: %s, currentKey: %s",
+				hex.EncodeToString(existingMaxKey), hex.EncodeToString(k)))
+		}
+	})
+	txw.putInternal(bucket, k, v)
+}
+
+func (txw *txWriteBuffer) putInternal(bucket Bucket, k, v []byte) {
+	b, ok := txw.buckets[bucket.ID()]
+	if !ok {
+		b = newBucketBuffer()
+		txw.buckets[bucket.ID()] = b
+	}
+	b.add(k, v)
+}
+
+func (txw *txWriteBuffer) reset() {
+	txw.txBuffer.reset()
+	for k := range txw.bucket2seq {
+		v, ok := txw.buckets[k]
+		if !ok {
+			delete(txw.bucket2seq, k)
+		} else if v.used == 0 {
+			txw.bucket2seq[k] = true
+		}
+	}
+}
+
+func (txw *txWriteBuffer) writeback(txr *txReadBuffer) {
+	for k, wb := range txw.buckets {
+		rb, ok := txr.buckets[k]
+		if !ok {
+			delete(txw.buckets, k)
+			if seq, ok := txw.bucket2seq[k]; ok && !seq {
+				wb.dedupe()
+			}
+			txr.buckets[k] = wb
+			continue
+		}
+		if seq, ok := txw.bucket2seq[k]; ok && !seq && wb.used > 1 {
+			// assume no duplicate keys
+			sort.Sort(wb)
+		}
+		rb.merge(wb)
+	}
+	txw.reset()
+	// increase the buffer version
+	txr.bufVersion++
+}
+
+// txReadBuffer accesses buffered updates.
+type txReadBuffer struct {
+	txBuffer
+	// bufVersion is used to check if the buffer is modified recently
+	bufVersion uint64
+}
+
+func (txr *txReadBuffer) Range(bucket Bucket, key, endKey []byte, limit int64) ([][]byte, [][]byte) {
+	if b := txr.buckets[bucket.ID()]; b != nil {
+		return b.Range(key, endKey, limit)
+	}
+	return nil, nil
+}
+
+func (txr *txReadBuffer) ForEach(bucket Bucket, visitor func(k, v []byte) error) error {
+	if b := txr.buckets[bucket.ID()]; b != nil {
+		return b.ForEach(visitor)
+	}
+	return nil
+}
+
+// unsafeCopy returns a copy of txReadBuffer, caller should acquire backend.readTx.RLock()
+func (txr *txReadBuffer) unsafeCopy() txReadBuffer {
+	txrCopy := txReadBuffer{
+		txBuffer: txBuffer{
+			buckets: make(map[BucketID]*bucketBuffer, len(txr.txBuffer.buckets)),
+		},
+		bufVersion: 0,
+	}
+	for bucketName, bucket := range txr.txBuffer.buckets {
+		txrCopy.txBuffer.buckets[bucketName] = bucket.CopyUsed()
+	}
+	return txrCopy
+}
+
+type kv struct {
+	key []byte
+	val []byte
+}
+
+// bucketBuffer buffers key-value pairs that are pending commit.
+type bucketBuffer struct {
+	buf []kv
+	// used tracks number of elements in use so buf can be reused without reallocation.
+	used int
+}
+
+func newBucketBuffer() *bucketBuffer {
+	return &bucketBuffer{buf: make([]kv, bucketBufferInitialSize), used: 0}
+}
+
+func (bb *bucketBuffer) Range(key, endKey []byte, limit int64) (keys [][]byte, vals [][]byte) {
+	f := func(i int) bool { return bytes.Compare(bb.buf[i].key, key) >= 0 }
+	idx := sort.Search(bb.used, f)
+	if idx < 0 || idx >= bb.used {
+		return nil, nil
+	}
+	if len(endKey) == 0 {
+		if bytes.Equal(key, bb.buf[idx].key) {
+			keys = append(keys, bb.buf[idx].key)
+			vals = append(vals, bb.buf[idx].val)
+		}
+		return keys, vals
+	}
+	if bytes.Compare(endKey, bb.buf[idx].key) <= 0 {
+		return nil, nil
+	}
+	for i := idx; i < bb.used && int64(len(keys)) < limit; i++ {
+		if bytes.Compare(endKey, bb.buf[i].key) <= 0 {
+			break
+		}
+		keys = append(keys, bb.buf[i].key)
+		vals = append(vals, bb.buf[i].val)
+	}
+	return keys, vals
+}
+
+func (bb *bucketBuffer) ForEach(visitor func(k, v []byte) error) error {
+	for i := 0; i < bb.used; i++ {
+		if err := visitor(bb.buf[i].key, bb.buf[i].val); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (bb *bucketBuffer) add(k, v []byte) {
+	bb.buf[bb.used].key, bb.buf[bb.used].val = k, v
+	bb.used++
+	if bb.used == len(bb.buf) {
+		buf := make([]kv, (3*len(bb.buf))/2)
+		copy(buf, bb.buf)
+		bb.buf = buf
+	}
+}
+
+// merge merges data from bbsrc into bb.
+func (bb *bucketBuffer) merge(bbsrc *bucketBuffer) {
+	for i := 0; i < bbsrc.used; i++ {
+		bb.add(bbsrc.buf[i].key, bbsrc.buf[i].val)
+	}
+	if bb.used == bbsrc.used {
+		return
+	}
+	if bytes.Compare(bb.buf[(bb.used-bbsrc.used)-1].key, bbsrc.buf[0].key) < 0 {
+		return
+	}
+	bb.dedupe()
+}
+
+// dedupe removes duplicates, using only newest update
+func (bb *bucketBuffer) dedupe() {
+	if bb.used <= 1 {
+		return
+	}
+	sort.Stable(bb)
+	widx := 0
+	for ridx := 1; ridx < bb.used; ridx++ {
+		if !bytes.Equal(bb.buf[ridx].key, bb.buf[widx].key) {
+			widx++
+		}
+		bb.buf[widx] = bb.buf[ridx]
+	}
+	bb.used = widx + 1
+}
+
+func (bb *bucketBuffer) Len() int { return bb.used }
+func (bb *bucketBuffer) Less(i, j int) bool {
+	return bytes.Compare(bb.buf[i].key, bb.buf[j].key) < 0
+}
+func (bb *bucketBuffer) Swap(i, j int) { bb.buf[i], bb.buf[j] = bb.buf[j], bb.buf[i] }
+
+func (bb *bucketBuffer) CopyUsed() *bucketBuffer {
+	verify.Assert(bb.used <= len(bb.buf),
+		"used (%d) should never be bigger than the length of buf (%d)", bb.used, len(bb.buf))
+	bbCopy := bucketBuffer{
+		buf:  make([]kv, bb.used),
+		used: bb.used,
+	}
+	copy(bbCopy.buf, bb.buf[:bb.used])
+	return &bbCopy
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/backend/verify.go b/vendor/go.etcd.io/etcd/server/v3/storage/backend/verify.go
new file mode 100644
index 0000000..206a8a4
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/backend/verify.go
@@ -0,0 +1,117 @@
+// Copyright 2022 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package backend
+
+import (
+	"fmt"
+	"runtime/debug"
+	"strings"
+
+	"github.com/google/go-cmp/cmp"
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/client/pkg/v3/verify"
+)
+
+const (
+	EnvVerifyValueLock verify.VerificationType = "lock"
+)
+
+func ValidateCalledInsideApply(lg *zap.Logger) {
+	if !verifyLockEnabled() {
+		return
+	}
+	if !insideApply() {
+		lg.Panic("Called outside of APPLY!", zap.Stack("stacktrace"))
+	}
+}
+
+func ValidateCalledOutSideApply(lg *zap.Logger) {
+	if !verifyLockEnabled() {
+		return
+	}
+	if insideApply() {
+		lg.Panic("Called inside of APPLY!", zap.Stack("stacktrace"))
+	}
+}
+
+func ValidateCalledInsideUnittest(lg *zap.Logger) {
+	if !verifyLockEnabled() {
+		return
+	}
+	if !insideUnittest() {
+		lg.Fatal("Lock called outside of unit test!", zap.Stack("stacktrace"))
+	}
+}
+
+func verifyLockEnabled() bool {
+	return verify.IsVerificationEnabled(EnvVerifyValueLock)
+}
+
+func insideApply() bool {
+	stackTraceStr := string(debug.Stack())
+
+	// Exclude the case of `MustHackySaveMemberToBackend`, which is
+	// used to workaround the situations which are already affected
+	// by https://github.com/etcd-io/etcd/issues/19557.
+	if strings.Contains(stackTraceStr, "MustHackySaveMemberToBackend") {
+		return false
+	}
+
+	return strings.Contains(stackTraceStr, ".applyEntries")
+}
+
+func insideUnittest() bool {
+	stackTraceStr := string(debug.Stack())
+	return strings.Contains(stackTraceStr, "_test.go") && !strings.Contains(stackTraceStr, "tests/")
+}
+
+// VerifyBackendConsistency verifies data in ReadTx and BatchTx are consistent.
+func VerifyBackendConsistency(b Backend, lg *zap.Logger, skipSafeRangeBucket bool, bucket ...Bucket) {
+	verify.Verify(func() {
+		if b == nil {
+			return
+		}
+		if lg != nil {
+			lg.Debug("verifyBackendConsistency", zap.Bool("skipSafeRangeBucket", skipSafeRangeBucket))
+		}
+		b.BatchTx().LockOutsideApply()
+		defer b.BatchTx().Unlock()
+		b.ReadTx().RLock()
+		defer b.ReadTx().RUnlock()
+		for _, bkt := range bucket {
+			if skipSafeRangeBucket && bkt.IsSafeRangeBucket() {
+				continue
+			}
+			unsafeVerifyTxConsistency(b, bkt)
+		}
+	})
+}
+
+func unsafeVerifyTxConsistency(b Backend, bucket Bucket) {
+	dataFromWriteTxn := map[string]string{}
+	b.BatchTx().UnsafeForEach(bucket, func(k, v []byte) error {
+		dataFromWriteTxn[string(k)] = string(v)
+		return nil
+	})
+	dataFromReadTxn := map[string]string{}
+	b.ReadTx().UnsafeForEach(bucket, func(k, v []byte) error {
+		dataFromReadTxn[string(k)] = string(v)
+		return nil
+	})
+	if diff := cmp.Diff(dataFromWriteTxn, dataFromReadTxn); diff != "" {
+		panic(fmt.Sprintf("bucket %s data mismatch\nwrite TXN: %v\nread TXN: %v\ndiff: %s", bucket.String(), dataFromWriteTxn, dataFromReadTxn, diff))
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/datadir/datadir.go b/vendor/go.etcd.io/etcd/server/v3/storage/datadir/datadir.go
new file mode 100644
index 0000000..ced7d76
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/datadir/datadir.go
@@ -0,0 +1,49 @@
+// Copyright 2021 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package datadir
+
+import "path/filepath"
+
+const (
+	memberDirSegment   = "member"
+	snapDirSegment     = "snap"
+	walDirSegment      = "wal"
+	backendFileSegment = "db"
+)
+
+func ToBackendFileName(dataDir string) string {
+	return filepath.Join(ToSnapDir(dataDir), backendFileSegment)
+}
+
+func ToSnapDir(dataDir string) string {
+	return filepath.Join(ToMemberDir(dataDir), snapDirSegment)
+}
+
+// ToWalDir returns the directory path for the member's WAL.
+//
+// Deprecated: use ToWALDir instead.
+//
+//revive:disable-next-line:var-naming
+func ToWalDir(dataDir string) string {
+	return ToWALDir(dataDir)
+}
+
+func ToWALDir(dataDir string) string {
+	return filepath.Join(ToMemberDir(dataDir), walDirSegment)
+}
+
+func ToMemberDir(dataDir string) string {
+	return filepath.Join(dataDir, memberDirSegment)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/datadir/doc.go b/vendor/go.etcd.io/etcd/server/v3/storage/datadir/doc.go
new file mode 100644
index 0000000..92ca4b2
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/datadir/doc.go
@@ -0,0 +1,17 @@
+// Copyright 2021 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package datadir
+
+// datadir contains functions to navigate file-layout of etcd data-directory.
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/hooks.go b/vendor/go.etcd.io/etcd/server/v3/storage/hooks.go
new file mode 100644
index 0000000..ffec71c
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/hooks.go
@@ -0,0 +1,60 @@
+// Copyright 2021 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package storage
+
+import (
+	"sync"
+
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/server/v3/etcdserver/cindex"
+	"go.etcd.io/etcd/server/v3/storage/backend"
+	"go.etcd.io/etcd/server/v3/storage/schema"
+	"go.etcd.io/raft/v3/raftpb"
+)
+
+type BackendHooks struct {
+	indexer cindex.ConsistentIndexer
+	lg      *zap.Logger
+
+	// confState to Be written in the next submitted Backend transaction (if dirty)
+	confState raftpb.ConfState
+	// first write changes it to 'dirty'. false by default, so
+	// not initialized `confState` is meaningless.
+	confStateDirty bool
+	confStateLock  sync.Mutex
+}
+
+func NewBackendHooks(lg *zap.Logger, indexer cindex.ConsistentIndexer) *BackendHooks {
+	return &BackendHooks{lg: lg, indexer: indexer}
+}
+
+func (bh *BackendHooks) OnPreCommitUnsafe(tx backend.UnsafeReadWriter) {
+	bh.indexer.UnsafeSave(tx)
+	bh.confStateLock.Lock()
+	defer bh.confStateLock.Unlock()
+	if bh.confStateDirty {
+		schema.MustUnsafeSaveConfStateToBackend(bh.lg, tx, &bh.confState)
+		// save bh.confState
+		bh.confStateDirty = false
+	}
+}
+
+func (bh *BackendHooks) SetConfState(confState *raftpb.ConfState) {
+	bh.confStateLock.Lock()
+	defer bh.confStateLock.Unlock()
+	bh.confState = *confState
+	bh.confStateDirty = true
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/metrics.go b/vendor/go.etcd.io/etcd/server/v3/storage/metrics.go
new file mode 100644
index 0000000..cb7f870
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/metrics.go
@@ -0,0 +1,30 @@
+// Copyright 2021 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package storage
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+var quotaBackendBytes = prometheus.NewGauge(prometheus.GaugeOpts{
+	Namespace: "etcd",
+	Subsystem: "server",
+	Name:      "quota_backend_bytes",
+	Help:      "Current backend storage quota size in bytes.",
+})
+
+func init() {
+	prometheus.MustRegister(quotaBackendBytes)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/doc.go b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/doc.go
new file mode 100644
index 0000000..ad5be03
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/doc.go
@@ -0,0 +1,16 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package mvcc defines etcd's stable MVCC storage.
+package mvcc
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/hash.go b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/hash.go
new file mode 100644
index 0000000..2161853
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/hash.go
@@ -0,0 +1,180 @@
+// Copyright 2022 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package mvcc
+
+import (
+	"hash"
+	"hash/crc32"
+	"sort"
+	"sync"
+
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/server/v3/storage/backend"
+	"go.etcd.io/etcd/server/v3/storage/schema"
+)
+
+const (
+	hashStorageMaxSize = 10
+)
+
+func unsafeHashByRev(tx backend.UnsafeReader, compactRevision, revision int64, keep map[Revision]struct{}) (KeyValueHash, error) {
+	h := newKVHasher(compactRevision, revision, keep)
+	err := tx.UnsafeForEach(schema.Key, func(k, v []byte) error {
+		h.WriteKeyValue(k, v)
+		return nil
+	})
+	return h.Hash(), err
+}
+
+type kvHasher struct {
+	hash            hash.Hash32
+	compactRevision int64
+	revision        int64
+	keep            map[Revision]struct{}
+}
+
+func newKVHasher(compactRev, rev int64, keep map[Revision]struct{}) kvHasher {
+	h := crc32.New(crc32.MakeTable(crc32.Castagnoli))
+	h.Write(schema.Key.Name())
+	return kvHasher{
+		hash:            h,
+		compactRevision: compactRev,
+		revision:        rev,
+		keep:            keep,
+	}
+}
+
+func (h *kvHasher) WriteKeyValue(k, v []byte) {
+	kr := BytesToRev(k)
+	upper := Revision{Main: h.revision + 1}
+	if !upper.GreaterThan(kr) {
+		return
+	}
+
+	isTombstone := BytesToBucketKey(k).tombstone
+
+	lower := Revision{Main: h.compactRevision + 1}
+	// skip revisions that are scheduled for deletion
+	// due to compacting; don't skip if there isn't one.
+	if lower.GreaterThan(kr) && len(h.keep) > 0 {
+		if _, ok := h.keep[kr]; !ok {
+			return
+		}
+	}
+
+	// When performing compaction, if the compacted revision is a
+	// tombstone, older versions (<= 3.5.15 or <= 3.4.33) will delete
+	// the tombstone. But newer versions (> 3.5.15 or > 3.4.33) won't
+	// delete it. So we should skip the tombstone in such cases when
+	// computing the hash to ensure that both older and newer versions
+	// can always generate the same hash values.
+	if kr.Main == h.compactRevision && isTombstone {
+		return
+	}
+
+	h.hash.Write(k)
+	h.hash.Write(v)
+}
+
+func (h *kvHasher) Hash() KeyValueHash {
+	return KeyValueHash{Hash: h.hash.Sum32(), CompactRevision: h.compactRevision, Revision: h.revision}
+}
+
+type KeyValueHash struct {
+	Hash            uint32
+	CompactRevision int64
+	Revision        int64
+}
+
+type HashStorage interface {
+	// Hash computes the hash of the whole backend keyspace,
+	// including key, lease, and other buckets in storage.
+	// This is designed for testing ONLY!
+	// Do not rely on this in production with ongoing transactions,
+	// since Hash operation does not hold MVCC locks.
+	// Use "HashByRev" method instead for "key" bucket consistency checks.
+	Hash() (hash uint32, revision int64, err error)
+
+	// HashByRev computes the hash of all MVCC revisions up to a given revision.
+	HashByRev(rev int64) (hash KeyValueHash, currentRev int64, err error)
+
+	// Store adds hash value in local cache, allowing it to be returned by HashByRev.
+	Store(valueHash KeyValueHash)
+
+	// Hashes returns list of up to `hashStorageMaxSize` newest previously stored hashes.
+	Hashes() []KeyValueHash
+}
+
+type hashStorage struct {
+	store  *store
+	hashMu sync.RWMutex
+	hashes []KeyValueHash
+	lg     *zap.Logger
+}
+
+func NewHashStorage(lg *zap.Logger, s *store) HashStorage {
+	return &hashStorage{
+		store: s,
+		lg:    lg,
+	}
+}
+
+func (s *hashStorage) Hash() (hash uint32, revision int64, err error) {
+	return s.store.hash()
+}
+
+func (s *hashStorage) HashByRev(rev int64) (KeyValueHash, int64, error) {
+	s.hashMu.RLock()
+	for _, h := range s.hashes {
+		if rev == h.Revision {
+			s.hashMu.RUnlock()
+
+			s.store.revMu.RLock()
+			currentRev := s.store.currentRev
+			s.store.revMu.RUnlock()
+			return h, currentRev, nil
+		}
+	}
+	s.hashMu.RUnlock()
+
+	return s.store.hashByRev(rev)
+}
+
+func (s *hashStorage) Store(hash KeyValueHash) {
+	s.lg.Info("storing new hash",
+		zap.Uint32("hash", hash.Hash),
+		zap.Int64("revision", hash.Revision),
+		zap.Int64("compact-revision", hash.CompactRevision),
+	)
+	s.hashMu.Lock()
+	defer s.hashMu.Unlock()
+	s.hashes = append(s.hashes, hash)
+	sort.Slice(s.hashes, func(i, j int) bool {
+		return s.hashes[i].Revision < s.hashes[j].Revision
+	})
+	if len(s.hashes) > hashStorageMaxSize {
+		s.hashes = s.hashes[len(s.hashes)-hashStorageMaxSize:]
+	}
+}
+
+func (s *hashStorage) Hashes() []KeyValueHash {
+	s.hashMu.RLock()
+	// Copy out hashes under lock just to be safe
+	hashes := make([]KeyValueHash, 0, len(s.hashes))
+	hashes = append(hashes, s.hashes...)
+	s.hashMu.RUnlock()
+	return hashes
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/index.go b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/index.go
new file mode 100644
index 0000000..f300831
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/index.go
@@ -0,0 +1,253 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package mvcc
+
+import (
+	"sync"
+
+	"github.com/google/btree"
+	"go.uber.org/zap"
+)
+
+type index interface {
+	Get(key []byte, atRev int64) (rev, created Revision, ver int64, err error)
+	Range(key, end []byte, atRev int64) ([][]byte, []Revision)
+	Revisions(key, end []byte, atRev int64, limit int) ([]Revision, int)
+	CountRevisions(key, end []byte, atRev int64) int
+	Put(key []byte, rev Revision)
+	Tombstone(key []byte, rev Revision) error
+	Compact(rev int64) map[Revision]struct{}
+	Keep(rev int64) map[Revision]struct{}
+	Equal(b index) bool
+
+	Insert(ki *keyIndex)
+	KeyIndex(ki *keyIndex) *keyIndex
+}
+
+type treeIndex struct {
+	sync.RWMutex
+	tree *btree.BTreeG[*keyIndex]
+	lg   *zap.Logger
+}
+
+func newTreeIndex(lg *zap.Logger) index {
+	return &treeIndex{
+		tree: btree.NewG(32, func(aki *keyIndex, bki *keyIndex) bool {
+			return aki.Less(bki)
+		}),
+		lg: lg,
+	}
+}
+
+func (ti *treeIndex) Put(key []byte, rev Revision) {
+	keyi := &keyIndex{key: key}
+
+	ti.Lock()
+	defer ti.Unlock()
+	okeyi, ok := ti.tree.Get(keyi)
+	if !ok {
+		keyi.put(ti.lg, rev.Main, rev.Sub)
+		ti.tree.ReplaceOrInsert(keyi)
+		return
+	}
+	okeyi.put(ti.lg, rev.Main, rev.Sub)
+}
+
+func (ti *treeIndex) Get(key []byte, atRev int64) (modified, created Revision, ver int64, err error) {
+	ti.RLock()
+	defer ti.RUnlock()
+	return ti.unsafeGet(key, atRev)
+}
+
+func (ti *treeIndex) unsafeGet(key []byte, atRev int64) (modified, created Revision, ver int64, err error) {
+	keyi := &keyIndex{key: key}
+	if keyi = ti.keyIndex(keyi); keyi == nil {
+		return Revision{}, Revision{}, 0, ErrRevisionNotFound
+	}
+	return keyi.get(ti.lg, atRev)
+}
+
+func (ti *treeIndex) KeyIndex(keyi *keyIndex) *keyIndex {
+	ti.RLock()
+	defer ti.RUnlock()
+	return ti.keyIndex(keyi)
+}
+
+func (ti *treeIndex) keyIndex(keyi *keyIndex) *keyIndex {
+	if ki, ok := ti.tree.Get(keyi); ok {
+		return ki
+	}
+	return nil
+}
+
+func (ti *treeIndex) unsafeVisit(key, end []byte, f func(ki *keyIndex) bool) {
+	keyi, endi := &keyIndex{key: key}, &keyIndex{key: end}
+
+	ti.tree.AscendGreaterOrEqual(keyi, func(item *keyIndex) bool {
+		if len(endi.key) > 0 && !item.Less(endi) {
+			return false
+		}
+		if !f(item) {
+			return false
+		}
+		return true
+	})
+}
+
+// Revisions returns limited number of revisions from key(included) to end(excluded)
+// at the given rev. The returned slice is sorted in the order of key. There is no limit if limit <= 0.
+// The second return parameter isn't capped by the limit and reflects the total number of revisions.
+func (ti *treeIndex) Revisions(key, end []byte, atRev int64, limit int) (revs []Revision, total int) {
+	ti.RLock()
+	defer ti.RUnlock()
+
+	if end == nil {
+		rev, _, _, err := ti.unsafeGet(key, atRev)
+		if err != nil {
+			return nil, 0
+		}
+		return []Revision{rev}, 1
+	}
+	ti.unsafeVisit(key, end, func(ki *keyIndex) bool {
+		if rev, _, _, err := ki.get(ti.lg, atRev); err == nil {
+			if limit <= 0 || len(revs) < limit {
+				revs = append(revs, rev)
+			}
+			total++
+		}
+		return true
+	})
+	return revs, total
+}
+
+// CountRevisions returns the number of revisions
+// from key(included) to end(excluded) at the given rev.
+func (ti *treeIndex) CountRevisions(key, end []byte, atRev int64) int {
+	ti.RLock()
+	defer ti.RUnlock()
+
+	if end == nil {
+		_, _, _, err := ti.unsafeGet(key, atRev)
+		if err != nil {
+			return 0
+		}
+		return 1
+	}
+	total := 0
+	ti.unsafeVisit(key, end, func(ki *keyIndex) bool {
+		if _, _, _, err := ki.get(ti.lg, atRev); err == nil {
+			total++
+		}
+		return true
+	})
+	return total
+}
+
+func (ti *treeIndex) Range(key, end []byte, atRev int64) (keys [][]byte, revs []Revision) {
+	ti.RLock()
+	defer ti.RUnlock()
+
+	if end == nil {
+		rev, _, _, err := ti.unsafeGet(key, atRev)
+		if err != nil {
+			return nil, nil
+		}
+		return [][]byte{key}, []Revision{rev}
+	}
+	ti.unsafeVisit(key, end, func(ki *keyIndex) bool {
+		if rev, _, _, err := ki.get(ti.lg, atRev); err == nil {
+			revs = append(revs, rev)
+			keys = append(keys, ki.key)
+		}
+		return true
+	})
+	return keys, revs
+}
+
+func (ti *treeIndex) Tombstone(key []byte, rev Revision) error {
+	keyi := &keyIndex{key: key}
+
+	ti.Lock()
+	defer ti.Unlock()
+	ki, ok := ti.tree.Get(keyi)
+	if !ok {
+		return ErrRevisionNotFound
+	}
+
+	return ki.tombstone(ti.lg, rev.Main, rev.Sub)
+}
+
+func (ti *treeIndex) Compact(rev int64) map[Revision]struct{} {
+	available := make(map[Revision]struct{})
+	ti.lg.Info("compact tree index", zap.Int64("revision", rev))
+	ti.Lock()
+	clone := ti.tree.Clone()
+	ti.Unlock()
+
+	clone.Ascend(func(keyi *keyIndex) bool {
+		// Lock is needed here to prevent modification to the keyIndex while
+		// compaction is going on or revision added to empty before deletion
+		ti.Lock()
+		keyi.compact(ti.lg, rev, available)
+		if keyi.isEmpty() {
+			_, ok := ti.tree.Delete(keyi)
+			if !ok {
+				ti.lg.Panic("failed to delete during compaction")
+			}
+		}
+		ti.Unlock()
+		return true
+	})
+	return available
+}
+
+// Keep finds all revisions to be kept for a Compaction at the given rev.
+func (ti *treeIndex) Keep(rev int64) map[Revision]struct{} {
+	available := make(map[Revision]struct{})
+	ti.RLock()
+	defer ti.RUnlock()
+	ti.tree.Ascend(func(keyi *keyIndex) bool {
+		keyi.keep(rev, available)
+		return true
+	})
+	return available
+}
+
+func (ti *treeIndex) Equal(bi index) bool {
+	b := bi.(*treeIndex)
+
+	if ti.tree.Len() != b.tree.Len() {
+		return false
+	}
+
+	equal := true
+
+	ti.tree.Ascend(func(aki *keyIndex) bool {
+		bki, _ := b.tree.Get(aki)
+		if !aki.equal(bki) {
+			equal = false
+			return false
+		}
+		return true
+	})
+
+	return equal
+}
+
+func (ti *treeIndex) Insert(ki *keyIndex) {
+	ti.Lock()
+	defer ti.Unlock()
+	ti.tree.ReplaceOrInsert(ki)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/key_index.go b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/key_index.go
new file mode 100644
index 0000000..1403519
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/key_index.go
@@ -0,0 +1,389 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package mvcc
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+
+	"go.uber.org/zap"
+)
+
+var ErrRevisionNotFound = errors.New("mvcc: revision not found")
+
+// keyIndex stores the revisions of a key in the backend.
+// Each keyIndex has at least one key generation.
+// Each generation might have several key versions.
+// Tombstone on a key appends a tombstone version at the end
+// of the current generation and creates a new empty generation.
+// Each version of a key has an index pointing to the backend.
+//
+// For example: put(1.0);put(2.0);tombstone(3.0);put(4.0);tombstone(5.0) on key "foo"
+// generate a keyIndex:
+// key:     "foo"
+// modified: 5
+// generations:
+//
+//	{empty}
+//	{4.0, 5.0(t)}
+//	{1.0, 2.0, 3.0(t)}
+//
+// Compact a keyIndex removes the versions with smaller or equal to
+// rev except the largest one. If the generation becomes empty
+// during compaction, it will be removed. if all the generations get
+// removed, the keyIndex should be removed.
+//
+// For example:
+// compact(2) on the previous example
+// generations:
+//
+//	{empty}
+//	{4.0, 5.0(t)}
+//	{2.0, 3.0(t)}
+//
+// compact(4)
+// generations:
+//
+//	{empty}
+//	{4.0, 5.0(t)}
+//
+// compact(5):
+// generations:
+//
+//	{empty}
+//	{5.0(t)}
+//
+// compact(6):
+// generations:
+//
+//	{empty} -> key SHOULD be removed.
+type keyIndex struct {
+	key         []byte
+	modified    Revision // the main rev of the last modification
+	generations []generation
+}
+
+// put puts a revision to the keyIndex.
+func (ki *keyIndex) put(lg *zap.Logger, main int64, sub int64) {
+	rev := Revision{Main: main, Sub: sub}
+
+	if !rev.GreaterThan(ki.modified) {
+		lg.Panic(
+			"'put' with an unexpected smaller revision",
+			zap.Int64("given-revision-main", rev.Main),
+			zap.Int64("given-revision-sub", rev.Sub),
+			zap.Int64("modified-revision-main", ki.modified.Main),
+			zap.Int64("modified-revision-sub", ki.modified.Sub),
+		)
+	}
+	if len(ki.generations) == 0 {
+		ki.generations = append(ki.generations, generation{})
+	}
+	g := &ki.generations[len(ki.generations)-1]
+	if len(g.revs) == 0 { // create a new key
+		keysGauge.Inc()
+		g.created = rev
+	}
+	g.revs = append(g.revs, rev)
+	g.ver++
+	ki.modified = rev
+}
+
+func (ki *keyIndex) restore(lg *zap.Logger, created, modified Revision, ver int64) {
+	if len(ki.generations) != 0 {
+		lg.Panic(
+			"'restore' got an unexpected non-empty generations",
+			zap.Int("generations-size", len(ki.generations)),
+		)
+	}
+
+	ki.modified = modified
+	g := generation{created: created, ver: ver, revs: []Revision{modified}}
+	ki.generations = append(ki.generations, g)
+	keysGauge.Inc()
+}
+
+// restoreTombstone is used to restore a tombstone revision, which is the only
+// revision so far for a key. We don't know the creating revision (i.e. already
+// compacted) of the key, so set it empty.
+func (ki *keyIndex) restoreTombstone(lg *zap.Logger, main, sub int64) {
+	ki.restore(lg, Revision{}, Revision{main, sub}, 1)
+	ki.generations = append(ki.generations, generation{})
+	keysGauge.Dec()
+}
+
+// tombstone puts a revision, pointing to a tombstone, to the keyIndex.
+// It also creates a new empty generation in the keyIndex.
+// It returns ErrRevisionNotFound when tombstone on an empty generation.
+func (ki *keyIndex) tombstone(lg *zap.Logger, main int64, sub int64) error {
+	if ki.isEmpty() {
+		lg.Panic(
+			"'tombstone' got an unexpected empty keyIndex",
+			zap.String("key", string(ki.key)),
+		)
+	}
+	if ki.generations[len(ki.generations)-1].isEmpty() {
+		return ErrRevisionNotFound
+	}
+	ki.put(lg, main, sub)
+	ki.generations = append(ki.generations, generation{})
+	keysGauge.Dec()
+	return nil
+}
+
+// get gets the modified, created revision and version of the key that satisfies the given atRev.
+// Rev must be smaller than or equal to the given atRev.
+func (ki *keyIndex) get(lg *zap.Logger, atRev int64) (modified, created Revision, ver int64, err error) {
+	if ki.isEmpty() {
+		lg.Panic(
+			"'get' got an unexpected empty keyIndex",
+			zap.String("key", string(ki.key)),
+		)
+	}
+	g := ki.findGeneration(atRev)
+	if g.isEmpty() {
+		return Revision{}, Revision{}, 0, ErrRevisionNotFound
+	}
+
+	n := g.walk(func(rev Revision) bool { return rev.Main > atRev })
+	if n != -1 {
+		return g.revs[n], g.created, g.ver - int64(len(g.revs)-n-1), nil
+	}
+
+	return Revision{}, Revision{}, 0, ErrRevisionNotFound
+}
+
+// since returns revisions since the given rev. Only the revision with the
+// largest sub revision will be returned if multiple revisions have the same
+// main revision.
+func (ki *keyIndex) since(lg *zap.Logger, rev int64) []Revision {
+	if ki.isEmpty() {
+		lg.Panic(
+			"'since' got an unexpected empty keyIndex",
+			zap.String("key", string(ki.key)),
+		)
+	}
+	since := Revision{Main: rev}
+	var gi int
+	// find the generations to start checking
+	for gi = len(ki.generations) - 1; gi > 0; gi-- {
+		g := ki.generations[gi]
+		if g.isEmpty() {
+			continue
+		}
+		if since.GreaterThan(g.created) {
+			break
+		}
+	}
+
+	var revs []Revision
+	var last int64
+	for ; gi < len(ki.generations); gi++ {
+		for _, r := range ki.generations[gi].revs {
+			if since.GreaterThan(r) {
+				continue
+			}
+			if r.Main == last {
+				// replace the revision with a new one that has higher sub value,
+				// because the original one should not be seen by external
+				revs[len(revs)-1] = r
+				continue
+			}
+			revs = append(revs, r)
+			last = r.Main
+		}
+	}
+	return revs
+}
+
+// compact compacts a keyIndex by removing the versions with smaller or equal
+// revision than the given atRev except the largest one.
+// If a generation becomes empty during compaction, it will be removed.
+func (ki *keyIndex) compact(lg *zap.Logger, atRev int64, available map[Revision]struct{}) {
+	if ki.isEmpty() {
+		lg.Panic(
+			"'compact' got an unexpected empty keyIndex",
+			zap.String("key", string(ki.key)),
+		)
+	}
+
+	genIdx, revIndex := ki.doCompact(atRev, available)
+
+	g := &ki.generations[genIdx]
+	if !g.isEmpty() {
+		// remove the previous contents.
+		if revIndex != -1 {
+			g.revs = g.revs[revIndex:]
+		}
+	}
+
+	// remove the previous generations.
+	ki.generations = ki.generations[genIdx:]
+}
+
+// keep finds the revision to be kept if compact is called at given atRev.
+func (ki *keyIndex) keep(atRev int64, available map[Revision]struct{}) {
+	if ki.isEmpty() {
+		return
+	}
+
+	genIdx, revIndex := ki.doCompact(atRev, available)
+	g := &ki.generations[genIdx]
+	if !g.isEmpty() {
+		// If the given `atRev` is a tombstone, we need to skip it.
+		//
+		// Note that this s different from the `compact` function which
+		// keeps tombstone in such case. We need to stay consistent with
+		// existing versions, ensuring they always generate the same hash
+		// values.
+		if revIndex == len(g.revs)-1 && genIdx != len(ki.generations)-1 {
+			delete(available, g.revs[revIndex])
+		}
+	}
+}
+
+func (ki *keyIndex) doCompact(atRev int64, available map[Revision]struct{}) (genIdx int, revIndex int) {
+	// walk until reaching the first revision smaller or equal to "atRev",
+	// and add the revision to the available map
+	f := func(rev Revision) bool {
+		if rev.Main <= atRev {
+			available[rev] = struct{}{}
+			return false
+		}
+		return true
+	}
+
+	genIdx, g := 0, &ki.generations[0]
+	// find first generation includes atRev or created after atRev
+	for genIdx < len(ki.generations)-1 {
+		if tomb := g.revs[len(g.revs)-1].Main; tomb >= atRev {
+			break
+		}
+		genIdx++
+		g = &ki.generations[genIdx]
+	}
+
+	revIndex = g.walk(f)
+
+	return genIdx, revIndex
+}
+
+func (ki *keyIndex) isEmpty() bool {
+	return len(ki.generations) == 1 && ki.generations[0].isEmpty()
+}
+
+// findGeneration finds out the generation of the keyIndex that the
+// given rev belongs to. If the given rev is at the gap of two generations,
+// which means that the key does not exist at the given rev, it returns nil.
+func (ki *keyIndex) findGeneration(rev int64) *generation {
+	lastg := len(ki.generations) - 1
+	cg := lastg
+
+	for cg >= 0 {
+		if len(ki.generations[cg].revs) == 0 {
+			cg--
+			continue
+		}
+		g := ki.generations[cg]
+		if cg != lastg {
+			if tomb := g.revs[len(g.revs)-1].Main; tomb <= rev {
+				return nil
+			}
+		}
+		if g.revs[0].Main <= rev {
+			return &ki.generations[cg]
+		}
+		cg--
+	}
+	return nil
+}
+
+func (ki *keyIndex) Less(bki *keyIndex) bool {
+	return bytes.Compare(ki.key, bki.key) == -1
+}
+
+func (ki *keyIndex) equal(b *keyIndex) bool {
+	if !bytes.Equal(ki.key, b.key) {
+		return false
+	}
+	if ki.modified != b.modified {
+		return false
+	}
+	if len(ki.generations) != len(b.generations) {
+		return false
+	}
+	for i := range ki.generations {
+		ag, bg := ki.generations[i], b.generations[i]
+		if !ag.equal(bg) {
+			return false
+		}
+	}
+	return true
+}
+
+func (ki *keyIndex) String() string {
+	var s string
+	for _, g := range ki.generations {
+		s += g.String()
+	}
+	return s
+}
+
+// generation contains multiple revisions of a key.
+type generation struct {
+	ver     int64
+	created Revision // when the generation is created (put in first revision).
+	revs    []Revision
+}
+
+func (g *generation) isEmpty() bool { return g == nil || len(g.revs) == 0 }
+
+// walk walks through the revisions in the generation in descending order.
+// It passes the revision to the given function.
+// walk returns until: 1. it finishes walking all pairs 2. the function returns false.
+// walk returns the position at where it stopped. If it stopped after
+// finishing walking, -1 will be returned.
+func (g *generation) walk(f func(rev Revision) bool) int {
+	l := len(g.revs)
+	for i := range g.revs {
+		ok := f(g.revs[l-i-1])
+		if !ok {
+			return l - i - 1
+		}
+	}
+	return -1
+}
+
+func (g *generation) String() string {
+	return fmt.Sprintf("g: created[%d] ver[%d], revs %#v\n", g.created, g.ver, g.revs)
+}
+
+func (g generation) equal(b generation) bool {
+	if g.ver != b.ver {
+		return false
+	}
+	if len(g.revs) != len(b.revs) {
+		return false
+	}
+
+	for i := range g.revs {
+		ar, br := g.revs[i], b.revs[i]
+		if ar != br {
+			return false
+		}
+	}
+	return true
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/kv.go b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/kv.go
new file mode 100644
index 0000000..6250bb9
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/kv.go
@@ -0,0 +1,147 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package mvcc
+
+import (
+	"context"
+
+	"go.etcd.io/etcd/api/v3/mvccpb"
+	"go.etcd.io/etcd/pkg/v3/traceutil"
+	"go.etcd.io/etcd/server/v3/lease"
+	"go.etcd.io/etcd/server/v3/storage/backend"
+)
+
+type RangeOptions struct {
+	Limit int64
+	Rev   int64
+	Count bool
+}
+
+type RangeResult struct {
+	KVs   []mvccpb.KeyValue
+	Rev   int64
+	Count int
+}
+
+type ReadView interface {
+	// FirstRev returns the first KV revision at the time of opening the txn.
+	// After a compaction, the first revision increases to the compaction
+	// revision.
+	FirstRev() int64
+
+	// Rev returns the revision of the KV at the time of opening the txn.
+	Rev() int64
+
+	// Range gets the keys in the range at rangeRev.
+	// The returned rev is the current revision of the KV when the operation is executed.
+	// If rangeRev <=0, range gets the keys at currentRev.
+	// If `end` is nil, the request returns the key.
+	// If `end` is not nil and not empty, it gets the keys in range [key, range_end).
+	// If `end` is not nil and empty, it gets the keys greater than or equal to key.
+	// Limit limits the number of keys returned.
+	// If the required rev is compacted, ErrCompacted will be returned.
+	Range(ctx context.Context, key, end []byte, ro RangeOptions) (r *RangeResult, err error)
+}
+
+// TxnRead represents a read-only transaction with operations that will not
+// block other read transactions.
+type TxnRead interface {
+	ReadView
+	// End marks the transaction is complete and ready to commit.
+	End()
+}
+
+type WriteView interface {
+	// DeleteRange deletes the given range from the store.
+	// A deleteRange increases the rev of the store if any key in the range exists.
+	// The number of key deleted will be returned.
+	// The returned rev is the current revision of the KV when the operation is executed.
+	// It also generates one event for each key delete in the event history.
+	// if the `end` is nil, deleteRange deletes the key.
+	// if the `end` is not nil, deleteRange deletes the keys in range [key, range_end).
+	DeleteRange(key, end []byte) (n, rev int64)
+
+	// Put puts the given key, value into the store. Put also takes additional argument lease to
+	// attach a lease to a key-value pair as meta-data. KV implementation does not validate the lease
+	// id.
+	// A put also increases the rev of the store, and generates one event in the event history.
+	// The returned rev is the current revision of the KV when the operation is executed.
+	Put(key, value []byte, lease lease.LeaseID) (rev int64)
+}
+
+// TxnWrite represents a transaction that can modify the store.
+type TxnWrite interface {
+	TxnRead
+	WriteView
+	// Changes gets the changes made since opening the write txn.
+	Changes() []mvccpb.KeyValue
+}
+
+// txnReadWrite coerces a read txn to a write, panicking on any write operation.
+type txnReadWrite struct{ TxnRead }
+
+func (trw *txnReadWrite) DeleteRange(key, end []byte) (n, rev int64) { panic("unexpected DeleteRange") }
+func (trw *txnReadWrite) Put(key, value []byte, lease lease.LeaseID) (rev int64) {
+	panic("unexpected Put")
+}
+func (trw *txnReadWrite) Changes() []mvccpb.KeyValue { return nil }
+
+func NewReadOnlyTxnWrite(txn TxnRead) TxnWrite { return &txnReadWrite{txn} }
+
+type ReadTxMode uint32
+
+const (
+	// Use ConcurrentReadTx and the txReadBuffer is copied
+	ConcurrentReadTxMode = ReadTxMode(1)
+	// Use backend ReadTx and txReadBuffer is not copied
+	SharedBufReadTxMode = ReadTxMode(2)
+)
+
+type KV interface {
+	ReadView
+	WriteView
+
+	// Read creates a read transaction.
+	Read(mode ReadTxMode, trace *traceutil.Trace) TxnRead
+
+	// Write creates a write transaction.
+	Write(trace *traceutil.Trace) TxnWrite
+
+	// HashStorage returns HashStorage interface for KV storage.
+	HashStorage() HashStorage
+
+	// Compact frees all superseded keys with revisions less than rev.
+	Compact(trace *traceutil.Trace, rev int64) (<-chan struct{}, error)
+
+	// Commit commits outstanding txns into the underlying backend.
+	Commit()
+
+	// Restore restores the KV store from a backend.
+	Restore(b backend.Backend) error
+	Close() error
+}
+
+// WatchableKV is a KV that can be watched.
+type WatchableKV interface {
+	KV
+	Watchable
+}
+
+// Watchable is the interface that wraps the NewWatchStream function.
+type Watchable interface {
+	// NewWatchStream returns a WatchStream that can be used to
+	// watch events happened or happening on the KV.
+	NewWatchStream() WatchStream
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/kv_view.go b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/kv_view.go
new file mode 100644
index 0000000..56260e7
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/kv_view.go
@@ -0,0 +1,56 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package mvcc
+
+import (
+	"context"
+
+	"go.etcd.io/etcd/pkg/v3/traceutil"
+	"go.etcd.io/etcd/server/v3/lease"
+)
+
+type readView struct{ kv KV }
+
+func (rv *readView) FirstRev() int64 {
+	tr := rv.kv.Read(ConcurrentReadTxMode, traceutil.TODO())
+	defer tr.End()
+	return tr.FirstRev()
+}
+
+func (rv *readView) Rev() int64 {
+	tr := rv.kv.Read(ConcurrentReadTxMode, traceutil.TODO())
+	defer tr.End()
+	return tr.Rev()
+}
+
+func (rv *readView) Range(ctx context.Context, key, end []byte, ro RangeOptions) (r *RangeResult, err error) {
+	tr := rv.kv.Read(ConcurrentReadTxMode, traceutil.TODO())
+	defer tr.End()
+	return tr.Range(ctx, key, end, ro)
+}
+
+type writeView struct{ kv KV }
+
+func (wv *writeView) DeleteRange(key, end []byte) (n, rev int64) {
+	tw := wv.kv.Write(traceutil.TODO())
+	defer tw.End()
+	return tw.DeleteRange(key, end)
+}
+
+func (wv *writeView) Put(key, value []byte, lease lease.LeaseID) (rev int64) {
+	tw := wv.kv.Write(traceutil.TODO())
+	defer tw.End()
+	return tw.Put(key, value, lease)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/kvstore.go b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/kvstore.go
new file mode 100644
index 0000000..77c5022
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/kvstore.go
@@ -0,0 +1,544 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package mvcc
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"math"
+	"sync"
+	"time"
+
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/api/v3/mvccpb"
+	"go.etcd.io/etcd/client/pkg/v3/verify"
+	"go.etcd.io/etcd/pkg/v3/schedule"
+	"go.etcd.io/etcd/pkg/v3/traceutil"
+	"go.etcd.io/etcd/server/v3/lease"
+	"go.etcd.io/etcd/server/v3/storage/backend"
+	"go.etcd.io/etcd/server/v3/storage/schema"
+)
+
+var (
+	ErrCompacted = errors.New("mvcc: required revision has been compacted")
+	ErrFutureRev = errors.New("mvcc: required revision is a future revision")
+)
+
+var (
+	restoreChunkKeys               = 10000 // non-const for testing
+	defaultCompactionBatchLimit    = 1000
+	defaultCompactionSleepInterval = 10 * time.Millisecond
+)
+
+type StoreConfig struct {
+	CompactionBatchLimit    int
+	CompactionSleepInterval time.Duration
+}
+
+type store struct {
+	ReadView
+	WriteView
+
+	cfg StoreConfig
+
+	// mu read locks for txns and write locks for non-txn store changes.
+	mu sync.RWMutex
+
+	b       backend.Backend
+	kvindex index
+
+	le lease.Lessor
+
+	// revMuLock protects currentRev and compactMainRev.
+	// Locked at end of write txn and released after write txn unlock lock.
+	// Locked before locking read txn and released after locking.
+	revMu sync.RWMutex
+	// currentRev is the revision of the last completed transaction.
+	currentRev int64
+	// compactMainRev is the main revision of the last compaction.
+	compactMainRev int64
+
+	fifoSched schedule.Scheduler
+
+	stopc chan struct{}
+
+	lg     *zap.Logger
+	hashes HashStorage
+}
+
+// NewStore returns a new store. It is useful to create a store inside
+// mvcc pkg. It should only be used for testing externally.
+// revive:disable-next-line:unexported-return this is used internally in the mvcc pkg
+func NewStore(lg *zap.Logger, b backend.Backend, le lease.Lessor, cfg StoreConfig) *store {
+	if lg == nil {
+		lg = zap.NewNop()
+	}
+	if cfg.CompactionBatchLimit == 0 {
+		cfg.CompactionBatchLimit = defaultCompactionBatchLimit
+	}
+	if cfg.CompactionSleepInterval == 0 {
+		cfg.CompactionSleepInterval = defaultCompactionSleepInterval
+	}
+	s := &store{
+		cfg:     cfg,
+		b:       b,
+		kvindex: newTreeIndex(lg),
+
+		le: le,
+
+		currentRev:     1,
+		compactMainRev: -1,
+
+		fifoSched: schedule.NewFIFOScheduler(lg),
+
+		stopc: make(chan struct{}),
+
+		lg: lg,
+	}
+	s.hashes = NewHashStorage(lg, s)
+	s.ReadView = &readView{s}
+	s.WriteView = &writeView{s}
+	if s.le != nil {
+		s.le.SetRangeDeleter(func() lease.TxnDelete { return s.Write(traceutil.TODO()) })
+	}
+
+	tx := s.b.BatchTx()
+	tx.LockOutsideApply()
+	tx.UnsafeCreateBucket(schema.Key)
+	schema.UnsafeCreateMetaBucket(tx)
+	tx.Unlock()
+	s.b.ForceCommit()
+
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if err := s.restore(); err != nil {
+		// TODO: return the error instead of panic here?
+		panic("failed to recover store from backend")
+	}
+
+	return s
+}
+
+func (s *store) compactBarrier(ctx context.Context, ch chan struct{}) {
+	if ctx == nil || ctx.Err() != nil {
+		select {
+		case <-s.stopc:
+		default:
+			// fix deadlock in mvcc, for more information, please refer to pr 11817.
+			// s.stopc is only updated in restore operation, which is called by apply
+			// snapshot call, compaction and apply snapshot requests are serialized by
+			// raft, and do not happen at the same time.
+			s.mu.Lock()
+			f := schedule.NewJob("kvstore_compactBarrier", func(ctx context.Context) { s.compactBarrier(ctx, ch) })
+			s.fifoSched.Schedule(f)
+			s.mu.Unlock()
+		}
+		return
+	}
+	close(ch)
+}
+
+func (s *store) hash() (hash uint32, revision int64, err error) {
+	// TODO: hash and revision could be inconsistent, one possible fix is to add s.revMu.RLock() at the beginning of function, which is costly
+	start := time.Now()
+
+	s.b.ForceCommit()
+	h, err := s.b.Hash(schema.DefaultIgnores)
+
+	hashSec.Observe(time.Since(start).Seconds())
+	return h, s.currentRev, err
+}
+
+func (s *store) hashByRev(rev int64) (hash KeyValueHash, currentRev int64, err error) {
+	var compactRev int64
+	start := time.Now()
+
+	s.mu.RLock()
+	s.revMu.RLock()
+	compactRev, currentRev = s.compactMainRev, s.currentRev
+	s.revMu.RUnlock()
+
+	if rev > 0 && rev < compactRev {
+		s.mu.RUnlock()
+		return KeyValueHash{}, 0, ErrCompacted
+	} else if rev > 0 && rev > currentRev {
+		s.mu.RUnlock()
+		return KeyValueHash{}, currentRev, ErrFutureRev
+	}
+	if rev == 0 {
+		rev = currentRev
+	}
+	keep := s.kvindex.Keep(rev)
+
+	tx := s.b.ReadTx()
+	tx.RLock()
+	defer tx.RUnlock()
+	s.mu.RUnlock()
+	hash, err = unsafeHashByRev(tx, compactRev, rev, keep)
+	hashRevSec.Observe(time.Since(start).Seconds())
+	return hash, currentRev, err
+}
+
+func (s *store) updateCompactRev(rev int64) (<-chan struct{}, int64, error) {
+	s.revMu.Lock()
+	if rev <= s.compactMainRev {
+		ch := make(chan struct{})
+		f := schedule.NewJob("kvstore_updateCompactRev_compactBarrier", func(ctx context.Context) { s.compactBarrier(ctx, ch) })
+		s.fifoSched.Schedule(f)
+		s.revMu.Unlock()
+		return ch, 0, ErrCompacted
+	}
+	if rev > s.currentRev {
+		s.revMu.Unlock()
+		return nil, 0, ErrFutureRev
+	}
+	compactMainRev := s.compactMainRev
+	s.compactMainRev = rev
+
+	SetScheduledCompact(s.b.BatchTx(), rev)
+	// ensure that desired compaction is persisted
+	// gofail: var compactBeforeCommitScheduledCompact struct{}
+	s.b.ForceCommit()
+	// gofail: var compactAfterCommitScheduledCompact struct{}
+
+	s.revMu.Unlock()
+
+	return nil, compactMainRev, nil
+}
+
+// checkPrevCompactionCompleted checks whether the previous scheduled compaction is completed.
+func (s *store) checkPrevCompactionCompleted() bool {
+	tx := s.b.ReadTx()
+	tx.RLock()
+	defer tx.RUnlock()
+	scheduledCompact, scheduledCompactFound := UnsafeReadScheduledCompact(tx)
+	finishedCompact, finishedCompactFound := UnsafeReadFinishedCompact(tx)
+	return scheduledCompact == finishedCompact && scheduledCompactFound == finishedCompactFound
+}
+
+func (s *store) compact(trace *traceutil.Trace, rev, prevCompactRev int64, prevCompactionCompleted bool) <-chan struct{} {
+	ch := make(chan struct{})
+	j := schedule.NewJob("kvstore_compact", func(ctx context.Context) {
+		if ctx.Err() != nil {
+			s.compactBarrier(ctx, ch)
+			return
+		}
+		hash, err := s.scheduleCompaction(rev, prevCompactRev)
+		if err != nil {
+			s.lg.Warn("Failed compaction", zap.Error(err))
+			s.compactBarrier(context.TODO(), ch)
+			return
+		}
+		// Only store the hash value if the previous hash is completed, i.e. this compaction
+		// hashes every revision from last compaction. For more details, see #15919.
+		if prevCompactionCompleted {
+			s.hashes.Store(hash)
+		} else {
+			s.lg.Info("previous compaction was interrupted, skip storing compaction hash value")
+		}
+		close(ch)
+	})
+
+	s.fifoSched.Schedule(j)
+	trace.Step("schedule compaction")
+	return ch
+}
+
+func (s *store) compactLockfree(rev int64) (<-chan struct{}, error) {
+	prevCompactionCompleted := s.checkPrevCompactionCompleted()
+	ch, prevCompactRev, err := s.updateCompactRev(rev)
+	if err != nil {
+		return ch, err
+	}
+
+	return s.compact(traceutil.TODO(), rev, prevCompactRev, prevCompactionCompleted), nil
+}
+
+func (s *store) Compact(trace *traceutil.Trace, rev int64) (<-chan struct{}, error) {
+	s.mu.Lock()
+	prevCompactionCompleted := s.checkPrevCompactionCompleted()
+	ch, prevCompactRev, err := s.updateCompactRev(rev)
+	trace.Step("check and update compact revision")
+	if err != nil {
+		s.mu.Unlock()
+		return ch, err
+	}
+	s.mu.Unlock()
+
+	return s.compact(trace, rev, prevCompactRev, prevCompactionCompleted), nil
+}
+
+func (s *store) Commit() {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	s.b.ForceCommit()
+}
+
+func (s *store) Restore(b backend.Backend) error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	close(s.stopc)
+	s.fifoSched.Stop()
+
+	s.b = b
+	s.kvindex = newTreeIndex(s.lg)
+
+	{
+		// During restore the metrics might report 'special' values
+		s.revMu.Lock()
+		s.currentRev = 1
+		s.compactMainRev = -1
+		s.revMu.Unlock()
+	}
+
+	s.fifoSched = schedule.NewFIFOScheduler(s.lg)
+	s.stopc = make(chan struct{})
+
+	return s.restore()
+}
+
+//nolint:unparam
+func (s *store) restore() error {
+	s.setupMetricsReporter()
+
+	min, max := NewRevBytes(), NewRevBytes()
+	min = RevToBytes(Revision{Main: 1}, min)
+	max = RevToBytes(Revision{Main: math.MaxInt64, Sub: math.MaxInt64}, max)
+
+	keyToLease := make(map[string]lease.LeaseID)
+
+	// restore index
+	tx := s.b.ReadTx()
+	tx.RLock()
+
+	finishedCompact, found := UnsafeReadFinishedCompact(tx)
+	if found {
+		s.revMu.Lock()
+		s.compactMainRev = finishedCompact
+
+		s.lg.Info(
+			"restored last compact revision",
+			zap.String("meta-bucket-name-key", string(schema.FinishedCompactKeyName)),
+			zap.Int64("restored-compact-revision", s.compactMainRev),
+		)
+		s.revMu.Unlock()
+	}
+	scheduledCompact, _ := UnsafeReadScheduledCompact(tx)
+	// index keys concurrently as they're loaded in from tx
+	keysGauge.Set(0)
+	rkvc, revc := restoreIntoIndex(s.lg, s.kvindex)
+	for {
+		keys, vals := tx.UnsafeRange(schema.Key, min, max, int64(restoreChunkKeys))
+		if len(keys) == 0 {
+			break
+		}
+		// rkvc blocks if the total pending keys exceeds the restore
+		// chunk size to keep keys from consuming too much memory.
+		restoreChunk(s.lg, rkvc, keys, vals, keyToLease)
+		if len(keys) < restoreChunkKeys {
+			// partial set implies final set
+			break
+		}
+		// next set begins after where this one ended
+		newMin := BytesToRev(keys[len(keys)-1][:revBytesLen])
+		newMin.Sub++
+		min = RevToBytes(newMin, min)
+	}
+	close(rkvc)
+
+	{
+		s.revMu.Lock()
+		s.currentRev = <-revc
+
+		// keys in the range [compacted revision -N, compaction] might all be deleted due to compaction.
+		// the correct revision should be set to compaction revision in the case, not the largest revision
+		// we have seen.
+		if s.currentRev < s.compactMainRev {
+			s.currentRev = s.compactMainRev
+		}
+
+		// If the latest revision was a tombstone revision and etcd just compacted
+		// it, but crashed right before persisting the FinishedCompactRevision,
+		// then it would lead to revision decreasing in bbolt db file. In such
+		// a scenario, we should adjust the current revision using the scheduled
+		// compact revision on bootstrap when etcd gets started again.
+		//
+		// See https://github.com/etcd-io/etcd/issues/17780#issuecomment-2061900231
+		if s.currentRev < scheduledCompact {
+			s.currentRev = scheduledCompact
+		}
+		s.revMu.Unlock()
+	}
+
+	if scheduledCompact <= s.compactMainRev {
+		scheduledCompact = 0
+	}
+
+	for key, lid := range keyToLease {
+		if s.le == nil {
+			tx.RUnlock()
+			panic("no lessor to attach lease")
+		}
+		err := s.le.Attach(lid, []lease.LeaseItem{{Key: key}})
+		if err != nil {
+			s.lg.Error(
+				"failed to attach a lease",
+				zap.String("lease-id", fmt.Sprintf("%016x", lid)),
+				zap.Error(err),
+			)
+		}
+	}
+	tx.RUnlock()
+
+	s.lg.Info("kvstore restored", zap.Int64("current-rev", s.currentRev))
+
+	if scheduledCompact != 0 {
+		if _, err := s.compactLockfree(scheduledCompact); err != nil {
+			s.lg.Warn("compaction encountered error",
+				zap.Int64("scheduled-compact-revision", scheduledCompact),
+				zap.Error(err),
+			)
+		} else {
+			s.lg.Info(
+				"resume scheduled compaction",
+				zap.Int64("scheduled-compact-revision", scheduledCompact),
+			)
+		}
+	}
+
+	return nil
+}
+
+type revKeyValue struct {
+	key  []byte
+	kv   mvccpb.KeyValue
+	kstr string
+}
+
+func restoreIntoIndex(lg *zap.Logger, idx index) (chan<- revKeyValue, <-chan int64) {
+	rkvc, revc := make(chan revKeyValue, restoreChunkKeys), make(chan int64, 1)
+	go func() {
+		currentRev := int64(1)
+		defer func() { revc <- currentRev }()
+		// restore the tree index from streaming the unordered index.
+		kiCache := make(map[string]*keyIndex, restoreChunkKeys)
+		for rkv := range rkvc {
+			ki, ok := kiCache[rkv.kstr]
+			// purge kiCache if many keys but still missing in the cache
+			if !ok && len(kiCache) >= restoreChunkKeys {
+				i := 10
+				for k := range kiCache {
+					delete(kiCache, k)
+					if i--; i == 0 {
+						break
+					}
+				}
+			}
+			// cache miss, fetch from tree index if there
+			if !ok {
+				ki = &keyIndex{key: rkv.kv.Key}
+				if idxKey := idx.KeyIndex(ki); idxKey != nil {
+					kiCache[rkv.kstr], ki = idxKey, idxKey
+					ok = true
+				}
+			}
+
+			rev := BytesToRev(rkv.key)
+			verify.Verify(func() {
+				if rev.Main < currentRev {
+					panic(fmt.Errorf("revision %d shouldn't be less than the previous revision %d", rev.Main, currentRev))
+				}
+			})
+			currentRev = rev.Main
+
+			if ok {
+				if isTombstone(rkv.key) {
+					if err := ki.tombstone(lg, rev.Main, rev.Sub); err != nil {
+						lg.Warn("tombstone encountered error", zap.Error(err))
+					}
+					continue
+				}
+				ki.put(lg, rev.Main, rev.Sub)
+			} else {
+				if isTombstone(rkv.key) {
+					ki.restoreTombstone(lg, rev.Main, rev.Sub)
+				} else {
+					ki.restore(lg, Revision{Main: rkv.kv.CreateRevision}, rev, rkv.kv.Version)
+				}
+				idx.Insert(ki)
+				kiCache[rkv.kstr] = ki
+			}
+		}
+	}()
+	return rkvc, revc
+}
+
+func restoreChunk(lg *zap.Logger, kvc chan<- revKeyValue, keys, vals [][]byte, keyToLease map[string]lease.LeaseID) {
+	for i, key := range keys {
+		rkv := revKeyValue{key: key}
+		if err := rkv.kv.Unmarshal(vals[i]); err != nil {
+			lg.Fatal("failed to unmarshal mvccpb.KeyValue", zap.Error(err))
+		}
+		rkv.kstr = string(rkv.kv.Key)
+		if isTombstone(key) {
+			delete(keyToLease, rkv.kstr)
+		} else if lid := lease.LeaseID(rkv.kv.Lease); lid != lease.NoLease {
+			keyToLease[rkv.kstr] = lid
+		} else {
+			delete(keyToLease, rkv.kstr)
+		}
+		kvc <- rkv
+	}
+}
+
+func (s *store) Close() error {
+	close(s.stopc)
+	s.fifoSched.Stop()
+	return nil
+}
+
+func (s *store) setupMetricsReporter() {
+	b := s.b
+	reportDbTotalSizeInBytesMu.Lock()
+	reportDbTotalSizeInBytes = func() float64 { return float64(b.Size()) }
+	reportDbTotalSizeInBytesMu.Unlock()
+	reportDbTotalSizeInUseInBytesMu.Lock()
+	reportDbTotalSizeInUseInBytes = func() float64 { return float64(b.SizeInUse()) }
+	reportDbTotalSizeInUseInBytesMu.Unlock()
+	reportDbOpenReadTxNMu.Lock()
+	reportDbOpenReadTxN = func() float64 { return float64(b.OpenReadTxN()) }
+	reportDbOpenReadTxNMu.Unlock()
+	reportCurrentRevMu.Lock()
+	reportCurrentRev = func() float64 {
+		s.revMu.RLock()
+		defer s.revMu.RUnlock()
+		return float64(s.currentRev)
+	}
+	reportCurrentRevMu.Unlock()
+	reportCompactRevMu.Lock()
+	reportCompactRev = func() float64 {
+		s.revMu.RLock()
+		defer s.revMu.RUnlock()
+		return float64(s.compactMainRev)
+	}
+	reportCompactRevMu.Unlock()
+}
+
+func (s *store) HashStorage() HashStorage {
+	return s.hashes
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/kvstore_compaction.go b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/kvstore_compaction.go
new file mode 100644
index 0000000..a052c93
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/kvstore_compaction.go
@@ -0,0 +1,98 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package mvcc
+
+import (
+	"encoding/binary"
+	"fmt"
+	"time"
+
+	humanize "github.com/dustin/go-humanize"
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/server/v3/storage/schema"
+)
+
+func (s *store) scheduleCompaction(compactMainRev, prevCompactRev int64) (KeyValueHash, error) {
+	totalStart := time.Now()
+	keep := s.kvindex.Compact(compactMainRev)
+	indexCompactionPauseMs.Observe(float64(time.Since(totalStart) / time.Millisecond))
+
+	totalStart = time.Now()
+	defer func() { dbCompactionTotalMs.Observe(float64(time.Since(totalStart) / time.Millisecond)) }()
+	keyCompactions := 0
+	defer func() { dbCompactionKeysCounter.Add(float64(keyCompactions)) }()
+	defer func() { dbCompactionLast.Set(float64(time.Now().Unix())) }()
+
+	end := make([]byte, 8)
+	binary.BigEndian.PutUint64(end, uint64(compactMainRev+1))
+
+	batchNum := s.cfg.CompactionBatchLimit
+	h := newKVHasher(prevCompactRev, compactMainRev, keep)
+	last := make([]byte, 8+1+8)
+	for {
+		var rev Revision
+
+		start := time.Now()
+
+		tx := s.b.BatchTx()
+		tx.LockOutsideApply()
+		keys, values := tx.UnsafeRange(schema.Key, last, end, int64(batchNum))
+		for i := range keys {
+			rev = BytesToRev(keys[i])
+			if _, ok := keep[rev]; !ok {
+				tx.UnsafeDelete(schema.Key, keys[i])
+				keyCompactions++
+			}
+			h.WriteKeyValue(keys[i], values[i])
+		}
+
+		if len(keys) < batchNum {
+			// gofail: var compactBeforeSetFinishedCompact struct{}
+			UnsafeSetFinishedCompact(tx, compactMainRev)
+			tx.Unlock()
+			dbCompactionPauseMs.Observe(float64(time.Since(start) / time.Millisecond))
+			// gofail: var compactAfterSetFinishedCompact struct{}
+			hash := h.Hash()
+			size, sizeInUse := s.b.Size(), s.b.SizeInUse()
+			s.lg.Info(
+				"finished scheduled compaction",
+				zap.Int64("compact-revision", compactMainRev),
+				zap.Duration("took", time.Since(totalStart)),
+				zap.Uint32("hash", hash.Hash),
+				zap.Int64("current-db-size-bytes", size),
+				zap.String("current-db-size", humanize.Bytes(uint64(size))),
+				zap.Int64("current-db-size-in-use-bytes", sizeInUse),
+				zap.String("current-db-size-in-use", humanize.Bytes(uint64(sizeInUse))),
+			)
+			return hash, nil
+		}
+
+		tx.Unlock()
+		// update last
+		last = RevToBytes(Revision{Main: rev.Main, Sub: rev.Sub + 1}, last)
+		// Immediately commit the compaction deletes instead of letting them accumulate in the write buffer
+		// gofail: var compactBeforeCommitBatch struct{}
+		s.b.ForceCommit()
+		// gofail: var compactAfterCommitBatch struct{}
+		dbCompactionPauseMs.Observe(float64(time.Since(start) / time.Millisecond))
+
+		select {
+		case <-time.After(s.cfg.CompactionSleepInterval):
+		case <-s.stopc:
+			return KeyValueHash{}, fmt.Errorf("interrupted due to stop signal")
+		}
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/kvstore_txn.go b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/kvstore_txn.go
new file mode 100644
index 0000000..c44a2cb
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/kvstore_txn.go
@@ -0,0 +1,321 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package mvcc
+
+import (
+	"context"
+	"fmt"
+
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/api/v3/mvccpb"
+	"go.etcd.io/etcd/pkg/v3/traceutil"
+	"go.etcd.io/etcd/server/v3/lease"
+	"go.etcd.io/etcd/server/v3/storage/backend"
+	"go.etcd.io/etcd/server/v3/storage/schema"
+)
+
+type storeTxnRead struct {
+	storeTxnCommon
+	tx backend.ReadTx
+}
+
+type storeTxnCommon struct {
+	s  *store
+	tx backend.UnsafeReader
+
+	firstRev int64
+	rev      int64
+
+	trace *traceutil.Trace
+}
+
+func (s *store) Read(mode ReadTxMode, trace *traceutil.Trace) TxnRead {
+	s.mu.RLock()
+	s.revMu.RLock()
+	// For read-only workloads, we use shared buffer by copying transaction read buffer
+	// for higher concurrency with ongoing blocking writes.
+	// For write/write-read transactions, we use the shared buffer
+	// rather than duplicating transaction read buffer to avoid transaction overhead.
+	var tx backend.ReadTx
+	if mode == ConcurrentReadTxMode {
+		tx = s.b.ConcurrentReadTx()
+	} else {
+		tx = s.b.ReadTx()
+	}
+
+	tx.RLock() // RLock is no-op. concurrentReadTx does not need to be locked after it is created.
+	firstRev, rev := s.compactMainRev, s.currentRev
+	s.revMu.RUnlock()
+	return newMetricsTxnRead(&storeTxnRead{storeTxnCommon{s, tx, firstRev, rev, trace}, tx})
+}
+
+func (tr *storeTxnCommon) FirstRev() int64 { return tr.firstRev }
+func (tr *storeTxnCommon) Rev() int64      { return tr.rev }
+
+func (tr *storeTxnCommon) Range(ctx context.Context, key, end []byte, ro RangeOptions) (r *RangeResult, err error) {
+	return tr.rangeKeys(ctx, key, end, tr.Rev(), ro)
+}
+
+func (tr *storeTxnCommon) rangeKeys(ctx context.Context, key, end []byte, curRev int64, ro RangeOptions) (*RangeResult, error) {
+	rev := ro.Rev
+	if rev > curRev {
+		return &RangeResult{KVs: nil, Count: -1, Rev: curRev}, ErrFutureRev
+	}
+	if rev <= 0 {
+		rev = curRev
+	}
+	if rev < tr.s.compactMainRev {
+		return &RangeResult{KVs: nil, Count: -1, Rev: 0}, ErrCompacted
+	}
+	if ro.Count {
+		total := tr.s.kvindex.CountRevisions(key, end, rev)
+		tr.trace.Step("count revisions from in-memory index tree")
+		return &RangeResult{KVs: nil, Count: total, Rev: curRev}, nil
+	}
+	revpairs, total := tr.s.kvindex.Revisions(key, end, rev, int(ro.Limit))
+	tr.trace.Step("range keys from in-memory index tree")
+	if len(revpairs) == 0 {
+		return &RangeResult{KVs: nil, Count: total, Rev: curRev}, nil
+	}
+
+	limit := int(ro.Limit)
+	if limit <= 0 || limit > len(revpairs) {
+		limit = len(revpairs)
+	}
+
+	kvs := make([]mvccpb.KeyValue, limit)
+	revBytes := NewRevBytes()
+	for i, revpair := range revpairs[:len(kvs)] {
+		select {
+		case <-ctx.Done():
+			return nil, fmt.Errorf("rangeKeys: context cancelled: %w", ctx.Err())
+		default:
+		}
+		revBytes = RevToBytes(revpair, revBytes)
+		_, vs := tr.tx.UnsafeRange(schema.Key, revBytes, nil, 0)
+		if len(vs) != 1 {
+			tr.s.lg.Fatal(
+				"range failed to find revision pair",
+				zap.Int64("revision-main", revpair.Main),
+				zap.Int64("revision-sub", revpair.Sub),
+				zap.Int64("revision-current", curRev),
+				zap.Int64("range-option-rev", ro.Rev),
+				zap.Int64("range-option-limit", ro.Limit),
+				zap.Binary("key", key),
+				zap.Binary("end", end),
+				zap.Int("len-revpairs", len(revpairs)),
+				zap.Int("len-values", len(vs)),
+			)
+		}
+		if err := kvs[i].Unmarshal(vs[0]); err != nil {
+			tr.s.lg.Fatal(
+				"failed to unmarshal mvccpb.KeyValue",
+				zap.Error(err),
+			)
+		}
+	}
+	tr.trace.Step("range keys from bolt db")
+	return &RangeResult{KVs: kvs, Count: total, Rev: curRev}, nil
+}
+
+func (tr *storeTxnRead) End() {
+	tr.tx.RUnlock() // RUnlock signals the end of concurrentReadTx.
+	tr.s.mu.RUnlock()
+}
+
+type storeTxnWrite struct {
+	storeTxnCommon
+	tx backend.BatchTx
+	// beginRev is the revision where the txn begins; it will write to the next revision.
+	beginRev int64
+	changes  []mvccpb.KeyValue
+}
+
+func (s *store) Write(trace *traceutil.Trace) TxnWrite {
+	s.mu.RLock()
+	tx := s.b.BatchTx()
+	tx.LockInsideApply()
+	tw := &storeTxnWrite{
+		storeTxnCommon: storeTxnCommon{s, tx, 0, 0, trace},
+		tx:             tx,
+		beginRev:       s.currentRev,
+		changes:        make([]mvccpb.KeyValue, 0, 4),
+	}
+	return newMetricsTxnWrite(tw)
+}
+
+func (tw *storeTxnWrite) Rev() int64 { return tw.beginRev }
+
+func (tw *storeTxnWrite) Range(ctx context.Context, key, end []byte, ro RangeOptions) (r *RangeResult, err error) {
+	rev := tw.beginRev
+	if len(tw.changes) > 0 {
+		rev++
+	}
+	return tw.rangeKeys(ctx, key, end, rev, ro)
+}
+
+func (tw *storeTxnWrite) DeleteRange(key, end []byte) (int64, int64) {
+	if n := tw.deleteRange(key, end); n != 0 || len(tw.changes) > 0 {
+		return n, tw.beginRev + 1
+	}
+	return 0, tw.beginRev
+}
+
+func (tw *storeTxnWrite) Put(key, value []byte, lease lease.LeaseID) int64 {
+	tw.put(key, value, lease)
+	return tw.beginRev + 1
+}
+
+func (tw *storeTxnWrite) End() {
+	// only update index if the txn modifies the mvcc state.
+	if len(tw.changes) != 0 {
+		// hold revMu lock to prevent new read txns from opening until writeback.
+		tw.s.revMu.Lock()
+		tw.s.currentRev++
+	}
+	tw.tx.Unlock()
+	if len(tw.changes) != 0 {
+		tw.s.revMu.Unlock()
+	}
+	tw.s.mu.RUnlock()
+}
+
+func (tw *storeTxnWrite) put(key, value []byte, leaseID lease.LeaseID) {
+	rev := tw.beginRev + 1
+	c := rev
+	oldLease := lease.NoLease
+
+	// if the key exists before, use its previous created and
+	// get its previous leaseID
+	_, created, ver, err := tw.s.kvindex.Get(key, rev)
+	if err == nil {
+		c = created.Main
+		oldLease = tw.s.le.GetLease(lease.LeaseItem{Key: string(key)})
+		tw.trace.Step("get key's previous created_revision and leaseID")
+	}
+	ibytes := NewRevBytes()
+	idxRev := Revision{Main: rev, Sub: int64(len(tw.changes))}
+	ibytes = RevToBytes(idxRev, ibytes)
+
+	ver = ver + 1
+	kv := mvccpb.KeyValue{
+		Key:            key,
+		Value:          value,
+		CreateRevision: c,
+		ModRevision:    rev,
+		Version:        ver,
+		Lease:          int64(leaseID),
+	}
+
+	d, err := kv.Marshal()
+	if err != nil {
+		tw.storeTxnCommon.s.lg.Fatal(
+			"failed to marshal mvccpb.KeyValue",
+			zap.Error(err),
+		)
+	}
+
+	tw.trace.Step("marshal mvccpb.KeyValue")
+	tw.tx.UnsafeSeqPut(schema.Key, ibytes, d)
+	tw.s.kvindex.Put(key, idxRev)
+	tw.changes = append(tw.changes, kv)
+	tw.trace.Step("store kv pair into bolt db")
+
+	if oldLease == leaseID {
+		tw.trace.Step("attach lease to kv pair")
+		return
+	}
+
+	if oldLease != lease.NoLease {
+		if tw.s.le == nil {
+			panic("no lessor to detach lease")
+		}
+		err = tw.s.le.Detach(oldLease, []lease.LeaseItem{{Key: string(key)}})
+		if err != nil {
+			tw.storeTxnCommon.s.lg.Error(
+				"failed to detach old lease from a key",
+				zap.Error(err),
+			)
+		}
+	}
+	if leaseID != lease.NoLease {
+		if tw.s.le == nil {
+			panic("no lessor to attach lease")
+		}
+		err = tw.s.le.Attach(leaseID, []lease.LeaseItem{{Key: string(key)}})
+		if err != nil {
+			panic("unexpected error from lease Attach")
+		}
+	}
+	tw.trace.Step("attach lease to kv pair")
+}
+
+func (tw *storeTxnWrite) deleteRange(key, end []byte) int64 {
+	rrev := tw.beginRev
+	if len(tw.changes) > 0 {
+		rrev++
+	}
+	keys, _ := tw.s.kvindex.Range(key, end, rrev)
+	if len(keys) == 0 {
+		return 0
+	}
+	for _, key := range keys {
+		tw.delete(key)
+	}
+	return int64(len(keys))
+}
+
+func (tw *storeTxnWrite) delete(key []byte) {
+	ibytes := NewRevBytes()
+	idxRev := newBucketKey(tw.beginRev+1, int64(len(tw.changes)), true)
+	ibytes = BucketKeyToBytes(idxRev, ibytes)
+
+	kv := mvccpb.KeyValue{Key: key}
+
+	d, err := kv.Marshal()
+	if err != nil {
+		tw.storeTxnCommon.s.lg.Fatal(
+			"failed to marshal mvccpb.KeyValue",
+			zap.Error(err),
+		)
+	}
+
+	tw.tx.UnsafeSeqPut(schema.Key, ibytes, d)
+	err = tw.s.kvindex.Tombstone(key, idxRev.Revision)
+	if err != nil {
+		tw.storeTxnCommon.s.lg.Fatal(
+			"failed to tombstone an existing key",
+			zap.String("key", string(key)),
+			zap.Error(err),
+		)
+	}
+	tw.changes = append(tw.changes, kv)
+
+	item := lease.LeaseItem{Key: string(key)}
+	leaseID := tw.s.le.GetLease(item)
+
+	if leaseID != lease.NoLease {
+		err = tw.s.le.Detach(leaseID, []lease.LeaseItem{item})
+		if err != nil {
+			tw.storeTxnCommon.s.lg.Error(
+				"failed to detach old lease from a key",
+				zap.Error(err),
+			)
+		}
+	}
+}
+
+func (tw *storeTxnWrite) Changes() []mvccpb.KeyValue { return tw.changes }
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/metrics.go b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/metrics.go
new file mode 100644
index 0000000..e060884
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/metrics.go
@@ -0,0 +1,321 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package mvcc
+
+import (
+	"sync"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+var (
+	rangeCounter = prometheus.NewCounter(
+		prometheus.CounterOpts{
+			Namespace: "etcd",
+			Subsystem: "mvcc",
+			Name:      "range_total",
+			Help:      "Total number of ranges seen by this member.",
+		},
+	)
+
+	putCounter = prometheus.NewCounter(
+		prometheus.CounterOpts{
+			Namespace: "etcd",
+			Subsystem: "mvcc",
+			Name:      "put_total",
+			Help:      "Total number of puts seen by this member.",
+		},
+	)
+
+	deleteCounter = prometheus.NewCounter(
+		prometheus.CounterOpts{
+			Namespace: "etcd",
+			Subsystem: "mvcc",
+			Name:      "delete_total",
+			Help:      "Total number of deletes seen by this member.",
+		},
+	)
+
+	txnCounter = prometheus.NewCounter(
+		prometheus.CounterOpts{
+			Namespace: "etcd",
+			Subsystem: "mvcc",
+			Name:      "txn_total",
+			Help:      "Total number of txns seen by this member.",
+		},
+	)
+
+	keysGauge = prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Namespace: "etcd_debugging",
+			Subsystem: "mvcc",
+			Name:      "keys_total",
+			Help:      "Total number of keys.",
+		},
+	)
+
+	watchStreamGauge = prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Namespace: "etcd_debugging",
+			Subsystem: "mvcc",
+			Name:      "watch_stream_total",
+			Help:      "Total number of watch streams.",
+		},
+	)
+
+	watcherGauge = prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Namespace: "etcd_debugging",
+			Subsystem: "mvcc",
+			Name:      "watcher_total",
+			Help:      "Total number of watchers.",
+		},
+	)
+
+	slowWatcherGauge = prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Namespace: "etcd_debugging",
+			Subsystem: "mvcc",
+			Name:      "slow_watcher_total",
+			Help:      "Total number of unsynced slow watchers.",
+		},
+	)
+
+	totalEventsCounter = prometheus.NewCounter(
+		prometheus.CounterOpts{
+			Namespace: "etcd_debugging",
+			Subsystem: "mvcc",
+			Name:      "events_total",
+			Help:      "Total number of events sent by this member.",
+		},
+	)
+
+	pendingEventsGauge = prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Namespace: "etcd_debugging",
+			Subsystem: "mvcc",
+			Name:      "pending_events_total",
+			Help:      "Total number of pending events to be sent.",
+		},
+	)
+
+	indexCompactionPauseMs = prometheus.NewHistogram(
+		prometheus.HistogramOpts{
+			Namespace: "etcd_debugging",
+			Subsystem: "mvcc",
+			Name:      "index_compaction_pause_duration_milliseconds",
+			Help:      "Bucketed histogram of index compaction pause duration.",
+
+			// lowest bucket start of upper bound 0.5 ms with factor 2
+			// highest bucket start of 0.5 ms * 2^13 == 4.096 sec
+			Buckets: prometheus.ExponentialBuckets(0.5, 2, 14),
+		},
+	)
+
+	dbCompactionPauseMs = prometheus.NewHistogram(
+		prometheus.HistogramOpts{
+			Namespace: "etcd_debugging",
+			Subsystem: "mvcc",
+			Name:      "db_compaction_pause_duration_milliseconds",
+			Help:      "Bucketed histogram of db compaction pause duration.",
+
+			// lowest bucket start of upper bound 1 ms with factor 2
+			// highest bucket start of 1 ms * 2^12 == 4.096 sec
+			Buckets: prometheus.ExponentialBuckets(1, 2, 13),
+		},
+	)
+
+	dbCompactionTotalMs = prometheus.NewHistogram(
+		prometheus.HistogramOpts{
+			Namespace: "etcd_debugging",
+			Subsystem: "mvcc",
+			Name:      "db_compaction_total_duration_milliseconds",
+			Help:      "Bucketed histogram of db compaction total duration.",
+
+			// lowest bucket start of upper bound 100 ms with factor 2
+			// highest bucket start of 100 ms * 2^13 == 8.192 sec
+			Buckets: prometheus.ExponentialBuckets(100, 2, 14),
+		},
+	)
+
+	dbCompactionLast = prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Namespace: "etcd_debugging",
+			Subsystem: "mvcc",
+			Name:      "db_compaction_last",
+			Help:      "The unix time of the last db compaction. Resets to 0 on start.",
+		},
+	)
+
+	dbCompactionKeysCounter = prometheus.NewCounter(
+		prometheus.CounterOpts{
+			Namespace: "etcd_debugging",
+			Subsystem: "mvcc",
+			Name:      "db_compaction_keys_total",
+			Help:      "Total number of db keys compacted.",
+		},
+	)
+
+	dbTotalSize = prometheus.NewGaugeFunc(
+		prometheus.GaugeOpts{
+			Namespace: "etcd",
+			Subsystem: "mvcc",
+			Name:      "db_total_size_in_bytes",
+			Help:      "Total size of the underlying database physically allocated in bytes.",
+		},
+		func() float64 {
+			reportDbTotalSizeInBytesMu.RLock()
+			defer reportDbTotalSizeInBytesMu.RUnlock()
+			return reportDbTotalSizeInBytes()
+		},
+	)
+	// overridden by mvcc initialization
+	reportDbTotalSizeInBytesMu sync.RWMutex
+	reportDbTotalSizeInBytes   = func() float64 { return 0 }
+
+	dbTotalSizeInUse = prometheus.NewGaugeFunc(
+		prometheus.GaugeOpts{
+			Namespace: "etcd",
+			Subsystem: "mvcc",
+			Name:      "db_total_size_in_use_in_bytes",
+			Help:      "Total size of the underlying database logically in use in bytes.",
+		},
+		func() float64 {
+			reportDbTotalSizeInUseInBytesMu.RLock()
+			defer reportDbTotalSizeInUseInBytesMu.RUnlock()
+			return reportDbTotalSizeInUseInBytes()
+		},
+	)
+	// overridden by mvcc initialization
+	reportDbTotalSizeInUseInBytesMu sync.RWMutex
+	reportDbTotalSizeInUseInBytes   = func() float64 { return 0 }
+
+	dbOpenReadTxN = prometheus.NewGaugeFunc(
+		prometheus.GaugeOpts{
+			Namespace: "etcd",
+			Subsystem: "mvcc",
+			Name:      "db_open_read_transactions",
+			Help:      "The number of currently open read transactions",
+		},
+
+		func() float64 {
+			reportDbOpenReadTxNMu.RLock()
+			defer reportDbOpenReadTxNMu.RUnlock()
+			return reportDbOpenReadTxN()
+		},
+	)
+	// overridden by mvcc initialization
+	reportDbOpenReadTxNMu sync.RWMutex
+	reportDbOpenReadTxN   = func() float64 { return 0 }
+
+	hashSec = prometheus.NewHistogram(prometheus.HistogramOpts{
+		Namespace: "etcd",
+		Subsystem: "mvcc",
+		Name:      "hash_duration_seconds",
+		Help:      "The latency distribution of storage hash operation.",
+
+		// 100 MB usually takes 100 ms, so start with 10 MB of 10 ms
+		// lowest bucket start of upper bound 0.01 sec (10 ms) with factor 2
+		// highest bucket start of 0.01 sec * 2^14 == 163.84 sec
+		Buckets: prometheus.ExponentialBuckets(.01, 2, 15),
+	})
+
+	hashRevSec = prometheus.NewHistogram(prometheus.HistogramOpts{
+		Namespace: "etcd",
+		Subsystem: "mvcc",
+		Name:      "hash_rev_duration_seconds",
+		Help:      "The latency distribution of storage hash by revision operation.",
+
+		// 100 MB usually takes 100 ms, so start with 10 MB of 10 ms
+		// lowest bucket start of upper bound 0.01 sec (10 ms) with factor 2
+		// highest bucket start of 0.01 sec * 2^14 == 163.84 sec
+		Buckets: prometheus.ExponentialBuckets(.01, 2, 15),
+	})
+
+	currentRev = prometheus.NewGaugeFunc(
+		prometheus.GaugeOpts{
+			Namespace: "etcd_debugging",
+			Subsystem: "mvcc",
+			Name:      "current_revision",
+			Help:      "The current revision of store.",
+		},
+		func() float64 {
+			reportCurrentRevMu.RLock()
+			defer reportCurrentRevMu.RUnlock()
+			return reportCurrentRev()
+		},
+	)
+	// overridden by mvcc initialization
+	reportCurrentRevMu sync.RWMutex
+	reportCurrentRev   = func() float64 { return 0 }
+
+	compactRev = prometheus.NewGaugeFunc(prometheus.GaugeOpts{
+		Namespace: "etcd_debugging",
+		Subsystem: "mvcc",
+		Name:      "compact_revision",
+		Help:      "The revision of the last compaction in store.",
+	},
+		func() float64 {
+			reportCompactRevMu.RLock()
+			defer reportCompactRevMu.RUnlock()
+			return reportCompactRev()
+		},
+	)
+	// overridden by mvcc initialization
+	reportCompactRevMu sync.RWMutex
+	reportCompactRev   = func() float64 { return 0 }
+
+	totalPutSizeGauge = prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Namespace: "etcd_debugging",
+			Subsystem: "mvcc",
+			Name:      "total_put_size_in_bytes",
+			Help:      "The total size of put kv pairs seen by this member.",
+		})
+)
+
+func init() {
+	prometheus.MustRegister(rangeCounter)
+	prometheus.MustRegister(putCounter)
+	prometheus.MustRegister(deleteCounter)
+	prometheus.MustRegister(txnCounter)
+	prometheus.MustRegister(keysGauge)
+	prometheus.MustRegister(watchStreamGauge)
+	prometheus.MustRegister(watcherGauge)
+	prometheus.MustRegister(slowWatcherGauge)
+	prometheus.MustRegister(totalEventsCounter)
+	prometheus.MustRegister(pendingEventsGauge)
+	prometheus.MustRegister(indexCompactionPauseMs)
+	prometheus.MustRegister(dbCompactionPauseMs)
+	prometheus.MustRegister(dbCompactionTotalMs)
+	prometheus.MustRegister(dbCompactionLast)
+	prometheus.MustRegister(dbCompactionKeysCounter)
+	prometheus.MustRegister(dbTotalSize)
+	prometheus.MustRegister(dbTotalSizeInUse)
+	prometheus.MustRegister(dbOpenReadTxN)
+	prometheus.MustRegister(hashSec)
+	prometheus.MustRegister(hashRevSec)
+	prometheus.MustRegister(currentRev)
+	prometheus.MustRegister(compactRev)
+	prometheus.MustRegister(totalPutSizeGauge)
+}
+
+// ReportEventReceived reports that an event is received.
+// This function should be called when the external systems received an
+// event from mvcc.Watcher.
+func ReportEventReceived(n int) {
+	pendingEventsGauge.Sub(float64(n))
+	totalEventsCounter.Add(float64(n))
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/metrics_txn.go b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/metrics_txn.go
new file mode 100644
index 0000000..aef877a
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/metrics_txn.go
@@ -0,0 +1,71 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package mvcc
+
+import (
+	"context"
+
+	"go.etcd.io/etcd/server/v3/lease"
+)
+
+type metricsTxnWrite struct {
+	TxnWrite
+	ranges  uint
+	puts    uint
+	deletes uint
+	putSize int64
+}
+
+func newMetricsTxnRead(tr TxnRead) TxnRead {
+	return &metricsTxnWrite{&txnReadWrite{tr}, 0, 0, 0, 0}
+}
+
+func newMetricsTxnWrite(tw TxnWrite) TxnWrite {
+	return &metricsTxnWrite{tw, 0, 0, 0, 0}
+}
+
+func (tw *metricsTxnWrite) Range(ctx context.Context, key, end []byte, ro RangeOptions) (*RangeResult, error) {
+	tw.ranges++
+	return tw.TxnWrite.Range(ctx, key, end, ro)
+}
+
+func (tw *metricsTxnWrite) DeleteRange(key, end []byte) (n, rev int64) {
+	tw.deletes++
+	return tw.TxnWrite.DeleteRange(key, end)
+}
+
+func (tw *metricsTxnWrite) Put(key, value []byte, lease lease.LeaseID) (rev int64) {
+	tw.puts++
+	size := int64(len(key) + len(value))
+	tw.putSize += size
+	return tw.TxnWrite.Put(key, value, lease)
+}
+
+func (tw *metricsTxnWrite) End() {
+	defer tw.TxnWrite.End()
+	if sum := tw.ranges + tw.puts + tw.deletes; sum > 1 {
+		txnCounter.Inc()
+	}
+
+	ranges := float64(tw.ranges)
+	rangeCounter.Add(ranges)
+
+	puts := float64(tw.puts)
+	putCounter.Add(puts)
+	totalPutSizeGauge.Add(float64(tw.putSize))
+
+	deletes := float64(tw.deletes)
+	deleteCounter.Add(deletes)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/revision.go b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/revision.go
new file mode 100644
index 0000000..7d1addf
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/revision.go
@@ -0,0 +1,126 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package mvcc
+
+import (
+	"encoding/binary"
+	"fmt"
+)
+
+const (
+	// revBytesLen is the byte length of a normal revision.
+	// First 8 bytes is the revision.main in big-endian format. The 9th byte
+	// is a '_'. The last 8 bytes is the revision.sub in big-endian format.
+	revBytesLen = 8 + 1 + 8
+	// markedRevBytesLen is the byte length of marked revision.
+	// The first `revBytesLen` bytes represents a normal revision. The last
+	// one byte is the mark.
+	markedRevBytesLen      = revBytesLen + 1
+	markBytePosition       = markedRevBytesLen - 1
+	markTombstone     byte = 't'
+)
+
+type Revision struct {
+	// Main is the main revision of a set of changes that happen atomically.
+	Main int64
+	// Sub is the sub revision of a change in a set of changes that happen
+	// atomically. Each change has different increasing sub revision in that
+	// set.
+	Sub int64
+}
+
+func (a Revision) GreaterThan(b Revision) bool {
+	if a.Main > b.Main {
+		return true
+	}
+	if a.Main < b.Main {
+		return false
+	}
+	return a.Sub > b.Sub
+}
+
+func RevToBytes(rev Revision, bytes []byte) []byte {
+	return BucketKeyToBytes(newBucketKey(rev.Main, rev.Sub, false), bytes)
+}
+
+func BytesToRev(bytes []byte) Revision {
+	return BytesToBucketKey(bytes).Revision
+}
+
+// BucketKey indicates modification of the key-value space.
+// The set of changes that share same main revision changes the key-value space atomically.
+type BucketKey struct {
+	Revision
+	tombstone bool
+}
+
+func newBucketKey(main, sub int64, isTombstone bool) BucketKey {
+	return BucketKey{
+		Revision: Revision{
+			Main: main,
+			Sub:  sub,
+		},
+		tombstone: isTombstone,
+	}
+}
+
+func NewRevBytes() []byte {
+	return make([]byte, revBytesLen, markedRevBytesLen)
+}
+
+func BucketKeyToBytes(rev BucketKey, bytes []byte) []byte {
+	binary.BigEndian.PutUint64(bytes, uint64(rev.Main))
+	bytes[8] = '_'
+	binary.BigEndian.PutUint64(bytes[9:], uint64(rev.Sub))
+	if rev.tombstone {
+		switch len(bytes) {
+		case revBytesLen:
+			bytes = append(bytes, markTombstone)
+		case markedRevBytesLen:
+			bytes[markBytePosition] = markTombstone
+		}
+	}
+	return bytes
+}
+
+func BytesToBucketKey(bytes []byte) BucketKey {
+	if (len(bytes) != revBytesLen) && (len(bytes) != markedRevBytesLen) {
+		panic(fmt.Sprintf("invalid revision length: %d", len(bytes)))
+	}
+	if bytes[8] != '_' {
+		panic(fmt.Sprintf("invalid separator in bucket key: %q", bytes[8]))
+	}
+	main := int64(binary.BigEndian.Uint64(bytes[0:8]))
+	sub := int64(binary.BigEndian.Uint64(bytes[9:]))
+	if main < 0 || sub < 0 {
+		panic(fmt.Sprintf("negative revision: main=%d sub=%d", main, sub))
+	}
+	return BucketKey{
+		Revision: Revision{
+			Main: main,
+			Sub:  sub,
+		},
+		tombstone: isTombstone(bytes),
+	}
+}
+
+// isTombstone checks whether the revision bytes is a tombstone.
+func isTombstone(b []byte) bool {
+	return len(b) == markedRevBytesLen && b[markBytePosition] == markTombstone
+}
+
+func IsTombstone(b []byte) bool {
+	return isTombstone(b)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/store.go b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/store.go
new file mode 100644
index 0000000..523b8cd
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/store.go
@@ -0,0 +1,60 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package mvcc
+
+import (
+	"go.etcd.io/etcd/server/v3/storage/backend"
+	"go.etcd.io/etcd/server/v3/storage/schema"
+)
+
+func UnsafeReadFinishedCompact(tx backend.UnsafeReader) (int64, bool) {
+	_, finishedCompactBytes := tx.UnsafeRange(schema.Meta, schema.FinishedCompactKeyName, nil, 0)
+	if len(finishedCompactBytes) != 0 {
+		return BytesToRev(finishedCompactBytes[0]).Main, true
+	}
+	return 0, false
+}
+
+func UnsafeReadScheduledCompact(tx backend.UnsafeReader) (int64, bool) {
+	_, scheduledCompactBytes := tx.UnsafeRange(schema.Meta, schema.ScheduledCompactKeyName, nil, 0)
+	if len(scheduledCompactBytes) != 0 {
+		return BytesToRev(scheduledCompactBytes[0]).Main, true
+	}
+	return 0, false
+}
+
+func SetScheduledCompact(tx backend.BatchTx, value int64) {
+	tx.LockInsideApply()
+	defer tx.Unlock()
+	UnsafeSetScheduledCompact(tx, value)
+}
+
+func UnsafeSetScheduledCompact(tx backend.UnsafeWriter, value int64) {
+	rbytes := NewRevBytes()
+	rbytes = RevToBytes(Revision{Main: value}, rbytes)
+	tx.UnsafePut(schema.Meta, schema.ScheduledCompactKeyName, rbytes)
+}
+
+func SetFinishedCompact(tx backend.BatchTx, value int64) {
+	tx.LockInsideApply()
+	defer tx.Unlock()
+	UnsafeSetFinishedCompact(tx, value)
+}
+
+func UnsafeSetFinishedCompact(tx backend.UnsafeWriter, value int64) {
+	rbytes := NewRevBytes()
+	rbytes = RevToBytes(Revision{Main: value}, rbytes)
+	tx.UnsafePut(schema.Meta, schema.FinishedCompactKeyName, rbytes)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/watchable_store.go b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/watchable_store.go
new file mode 100644
index 0000000..67b2d7f
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/watchable_store.go
@@ -0,0 +1,635 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package mvcc
+
+import (
+	"fmt"
+	"sync"
+	"time"
+
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/api/v3/mvccpb"
+	"go.etcd.io/etcd/client/pkg/v3/verify"
+	clientv3 "go.etcd.io/etcd/client/v3"
+	"go.etcd.io/etcd/pkg/v3/traceutil"
+	"go.etcd.io/etcd/server/v3/lease"
+	"go.etcd.io/etcd/server/v3/storage/backend"
+	"go.etcd.io/etcd/server/v3/storage/schema"
+)
+
+// non-const so modifiable by tests
+var (
+	// chanBufLen is the length of the buffered chan
+	// for sending out watched events.
+	// See https://github.com/etcd-io/etcd/issues/11906 for more detail.
+	chanBufLen = 128
+
+	// maxWatchersPerSync is the number of watchers to sync in a single batch
+	maxWatchersPerSync = 512
+
+	// maxResyncPeriod is the period of executing resync.
+	watchResyncPeriod = 100 * time.Millisecond
+)
+
+func ChanBufLen() int { return chanBufLen }
+
+type watchable interface {
+	watch(key, end []byte, startRev int64, id WatchID, ch chan<- WatchResponse, fcs ...FilterFunc) (*watcher, cancelFunc)
+	progress(w *watcher)
+	progressAll(watchers map[WatchID]*watcher) bool
+	rev() int64
+}
+
+type watchableStore struct {
+	*store
+
+	// mu protects watcher groups and batches. It should never be locked
+	// before locking store.mu to avoid deadlock.
+	mu sync.RWMutex
+
+	// victims are watcher batches that were blocked on the watch channel
+	victims []watcherBatch
+	victimc chan struct{}
+
+	// contains all unsynced watchers that needs to sync with events that have happened
+	unsynced watcherGroup
+
+	// contains all synced watchers that are in sync with the progress of the store.
+	// The key of the map is the key that the watcher watches on.
+	synced watcherGroup
+
+	stopc chan struct{}
+	wg    sync.WaitGroup
+}
+
+var _ WatchableKV = (*watchableStore)(nil)
+
+// cancelFunc updates unsynced and synced maps when running
+// cancel operations.
+type cancelFunc func()
+
+func New(lg *zap.Logger, b backend.Backend, le lease.Lessor, cfg StoreConfig) WatchableKV {
+	s := newWatchableStore(lg, b, le, cfg)
+	s.wg.Add(2)
+	go s.syncWatchersLoop()
+	go s.syncVictimsLoop()
+	return s
+}
+
+func newWatchableStore(lg *zap.Logger, b backend.Backend, le lease.Lessor, cfg StoreConfig) *watchableStore {
+	if lg == nil {
+		lg = zap.NewNop()
+	}
+	s := &watchableStore{
+		store:    NewStore(lg, b, le, cfg),
+		victimc:  make(chan struct{}, 1),
+		unsynced: newWatcherGroup(),
+		synced:   newWatcherGroup(),
+		stopc:    make(chan struct{}),
+	}
+	s.store.ReadView = &readView{s}
+	s.store.WriteView = &writeView{s}
+	if s.le != nil {
+		// use this store as the deleter so revokes trigger watch events
+		s.le.SetRangeDeleter(func() lease.TxnDelete { return s.Write(traceutil.TODO()) })
+	}
+	return s
+}
+
+func (s *watchableStore) Close() error {
+	close(s.stopc)
+	s.wg.Wait()
+	return s.store.Close()
+}
+
+func (s *watchableStore) NewWatchStream() WatchStream {
+	watchStreamGauge.Inc()
+	return &watchStream{
+		watchable: s,
+		ch:        make(chan WatchResponse, chanBufLen),
+		cancels:   make(map[WatchID]cancelFunc),
+		watchers:  make(map[WatchID]*watcher),
+	}
+}
+
+func (s *watchableStore) watch(key, end []byte, startRev int64, id WatchID, ch chan<- WatchResponse, fcs ...FilterFunc) (*watcher, cancelFunc) {
+	wa := &watcher{
+		key:      key,
+		end:      end,
+		startRev: startRev,
+		minRev:   startRev,
+		id:       id,
+		ch:       ch,
+		fcs:      fcs,
+	}
+
+	s.mu.Lock()
+	s.revMu.RLock()
+	synced := startRev > s.store.currentRev || startRev == 0
+	if synced {
+		wa.minRev = s.store.currentRev + 1
+		if startRev > wa.minRev {
+			wa.minRev = startRev
+		}
+		s.synced.add(wa)
+	} else {
+		slowWatcherGauge.Inc()
+		s.unsynced.add(wa)
+	}
+	s.revMu.RUnlock()
+	s.mu.Unlock()
+
+	watcherGauge.Inc()
+
+	return wa, func() { s.cancelWatcher(wa) }
+}
+
+// cancelWatcher removes references of the watcher from the watchableStore
+func (s *watchableStore) cancelWatcher(wa *watcher) {
+	for {
+		s.mu.Lock()
+		if s.unsynced.delete(wa) {
+			slowWatcherGauge.Dec()
+			watcherGauge.Dec()
+			break
+		} else if s.synced.delete(wa) {
+			watcherGauge.Dec()
+			break
+		} else if wa.ch == nil {
+			// already canceled (e.g., cancel/close race)
+			break
+		} else if wa.compacted {
+			watcherGauge.Dec()
+			break
+		}
+
+		if !wa.victim {
+			s.mu.Unlock()
+			panic("watcher not victim but not in watch groups")
+		}
+
+		var victimBatch watcherBatch
+		for _, wb := range s.victims {
+			if wb[wa] != nil {
+				victimBatch = wb
+				break
+			}
+		}
+		if victimBatch != nil {
+			slowWatcherGauge.Dec()
+			watcherGauge.Dec()
+			delete(victimBatch, wa)
+			break
+		}
+
+		// victim being processed so not accessible; retry
+		s.mu.Unlock()
+		time.Sleep(time.Millisecond)
+	}
+
+	wa.ch = nil
+	s.mu.Unlock()
+}
+
+func (s *watchableStore) Restore(b backend.Backend) error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	err := s.store.Restore(b)
+	if err != nil {
+		return err
+	}
+
+	for wa := range s.synced.watchers {
+		wa.restore = true
+		s.unsynced.add(wa)
+	}
+	s.synced = newWatcherGroup()
+	return nil
+}
+
+// syncWatchersLoop syncs the watcher in the unsynced map every 100ms.
+func (s *watchableStore) syncWatchersLoop() {
+	defer s.wg.Done()
+
+	delayTicker := time.NewTicker(watchResyncPeriod)
+	defer delayTicker.Stop()
+	var evs []mvccpb.Event
+
+	for {
+		s.mu.RLock()
+		st := time.Now()
+		lastUnsyncedWatchers := s.unsynced.size()
+		s.mu.RUnlock()
+
+		unsyncedWatchers := 0
+		if lastUnsyncedWatchers > 0 {
+			unsyncedWatchers, evs = s.syncWatchers(evs)
+		}
+		syncDuration := time.Since(st)
+
+		delayTicker.Reset(watchResyncPeriod)
+		// more work pending?
+		if unsyncedWatchers != 0 && lastUnsyncedWatchers > unsyncedWatchers {
+			// be fair to other store operations by yielding time taken
+			delayTicker.Reset(syncDuration)
+		}
+
+		select {
+		case <-delayTicker.C:
+		case <-s.stopc:
+			return
+		}
+	}
+}
+
+// syncVictimsLoop tries to write precomputed watcher responses to
+// watchers that had a blocked watcher channel
+func (s *watchableStore) syncVictimsLoop() {
+	defer s.wg.Done()
+
+	for {
+		for s.moveVictims() != 0 {
+			// try to update all victim watchers
+		}
+		s.mu.RLock()
+		isEmpty := len(s.victims) == 0
+		s.mu.RUnlock()
+
+		var tickc <-chan time.Time
+		if !isEmpty {
+			tickc = time.After(10 * time.Millisecond)
+		}
+
+		select {
+		case <-tickc:
+		case <-s.victimc:
+		case <-s.stopc:
+			return
+		}
+	}
+}
+
+// moveVictims tries to update watches with already pending event data
+func (s *watchableStore) moveVictims() (moved int) {
+	s.mu.Lock()
+	victims := s.victims
+	s.victims = nil
+	s.mu.Unlock()
+
+	var newVictim watcherBatch
+	for _, wb := range victims {
+		// try to send responses again
+		for w, eb := range wb {
+			// watcher has observed the store up to, but not including, w.minRev
+			rev := w.minRev - 1
+			if !w.send(WatchResponse{WatchID: w.id, Events: eb.evs, Revision: rev}) {
+				if newVictim == nil {
+					newVictim = make(watcherBatch)
+				}
+				newVictim[w] = eb
+				continue
+			}
+			pendingEventsGauge.Add(float64(len(eb.evs)))
+			moved++
+		}
+
+		// assign completed victim watchers to unsync/sync
+		s.mu.Lock()
+		s.store.revMu.RLock()
+		curRev := s.store.currentRev
+		for w, eb := range wb {
+			if newVictim != nil && newVictim[w] != nil {
+				// couldn't send watch response; stays victim
+				continue
+			}
+			w.victim = false
+			if eb.moreRev != 0 {
+				w.minRev = eb.moreRev
+			}
+			if w.minRev <= curRev {
+				s.unsynced.add(w)
+			} else {
+				slowWatcherGauge.Dec()
+				s.synced.add(w)
+			}
+		}
+		s.store.revMu.RUnlock()
+		s.mu.Unlock()
+	}
+
+	if len(newVictim) > 0 {
+		s.mu.Lock()
+		s.victims = append(s.victims, newVictim)
+		s.mu.Unlock()
+	}
+
+	return moved
+}
+
+// syncWatchers syncs unsynced watchers by:
+//  1. choose a set of watchers from the unsynced watcher group
+//  2. iterate over the set to get the minimum revision and remove compacted watchers
+//  3. use minimum revision to get all key-value pairs and send those events to watchers
+//  4. remove synced watchers in set from unsynced group and move to synced group
+func (s *watchableStore) syncWatchers(evs []mvccpb.Event) (int, []mvccpb.Event) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	if s.unsynced.size() == 0 {
+		return 0, []mvccpb.Event{}
+	}
+
+	s.store.revMu.RLock()
+	defer s.store.revMu.RUnlock()
+
+	// in order to find key-value pairs from unsynced watchers, we need to
+	// find min revision index, and these revisions can be used to
+	// query the backend store of key-value pairs
+	curRev := s.store.currentRev
+	compactionRev := s.store.compactMainRev
+
+	wg, minRev := s.unsynced.choose(maxWatchersPerSync, curRev, compactionRev)
+	evs = rangeEventsWithReuse(s.store.lg, s.store.b, evs, minRev, curRev+1)
+
+	victims := make(watcherBatch)
+	wb := newWatcherBatch(wg, evs)
+	for w := range wg.watchers {
+		if w.minRev < compactionRev {
+			// Skip the watcher that failed to send compacted watch response due to w.ch is full.
+			// Next retry of syncWatchers would try to resend the compacted watch response to w.ch
+			continue
+		}
+		w.minRev = max(curRev+1, w.minRev)
+
+		eb, ok := wb[w]
+		if !ok {
+			// bring un-notified watcher to synced
+			s.synced.add(w)
+			s.unsynced.delete(w)
+			continue
+		}
+
+		if eb.moreRev != 0 {
+			w.minRev = eb.moreRev
+		}
+
+		if w.send(WatchResponse{WatchID: w.id, Events: eb.evs, Revision: curRev}) {
+			pendingEventsGauge.Add(float64(len(eb.evs)))
+		} else {
+			w.victim = true
+		}
+
+		if w.victim {
+			victims[w] = eb
+		} else {
+			if eb.moreRev != 0 {
+				// stay unsynced; more to read
+				continue
+			}
+			s.synced.add(w)
+		}
+		s.unsynced.delete(w)
+	}
+	s.addVictim(victims)
+
+	vsz := 0
+	for _, v := range s.victims {
+		vsz += len(v)
+	}
+	slowWatcherGauge.Set(float64(s.unsynced.size() + vsz))
+
+	return s.unsynced.size(), evs
+}
+
+// rangeEventsWithReuse returns events in range [minRev, maxRev), while reusing already provided events.
+func rangeEventsWithReuse(lg *zap.Logger, b backend.Backend, evs []mvccpb.Event, minRev, maxRev int64) []mvccpb.Event {
+	if len(evs) == 0 {
+		return rangeEvents(lg, b, minRev, maxRev)
+	}
+	// append from left
+	if evs[0].Kv.ModRevision > minRev {
+		evs = append(rangeEvents(lg, b, minRev, evs[0].Kv.ModRevision), evs...)
+	}
+	// cut from left
+	prefixIndex := 0
+	for prefixIndex < len(evs) && evs[prefixIndex].Kv.ModRevision < minRev {
+		prefixIndex++
+	}
+	evs = evs[prefixIndex:]
+
+	if len(evs) == 0 {
+		return rangeEvents(lg, b, minRev, maxRev)
+	}
+	// append from right
+	if evs[len(evs)-1].Kv.ModRevision+1 < maxRev {
+		evs = append(evs, rangeEvents(lg, b, evs[len(evs)-1].Kv.ModRevision+1, maxRev)...)
+	}
+	// cut from right
+	suffixIndex := len(evs) - 1
+	for suffixIndex >= 0 && evs[suffixIndex].Kv.ModRevision >= maxRev {
+		suffixIndex--
+	}
+	evs = evs[:suffixIndex+1]
+	return evs
+}
+
+// rangeEvents returns events in range [minRev, maxRev).
+func rangeEvents(lg *zap.Logger, b backend.Backend, minRev, maxRev int64) []mvccpb.Event {
+	minBytes, maxBytes := NewRevBytes(), NewRevBytes()
+	minBytes = RevToBytes(Revision{Main: minRev}, minBytes)
+	maxBytes = RevToBytes(Revision{Main: maxRev}, maxBytes)
+
+	// UnsafeRange returns keys and values. And in boltdb, keys are revisions.
+	// values are actual key-value pairs in backend.
+	tx := b.ReadTx()
+	tx.RLock()
+	revs, vs := tx.UnsafeRange(schema.Key, minBytes, maxBytes, 0)
+	evs := kvsToEvents(lg, revs, vs)
+	// Must unlock after kvsToEvents, because vs (come from boltdb memory) is not deep copy.
+	// We can only unlock after Unmarshal, which will do deep copy.
+	// Otherwise we will trigger SIGSEGV during boltdb re-mmap.
+	tx.RUnlock()
+	return evs
+}
+
+// kvsToEvents gets all events for the watchers from all key-value pairs
+func kvsToEvents(lg *zap.Logger, revs, vals [][]byte) (evs []mvccpb.Event) {
+	for i, v := range vals {
+		var kv mvccpb.KeyValue
+		if err := kv.Unmarshal(v); err != nil {
+			lg.Panic("failed to unmarshal mvccpb.KeyValue", zap.Error(err))
+		}
+
+		ty := mvccpb.PUT
+		if isTombstone(revs[i]) {
+			ty = mvccpb.DELETE
+			// patch in mod revision so watchers won't skip
+			kv.ModRevision = BytesToRev(revs[i]).Main
+		}
+		evs = append(evs, mvccpb.Event{Kv: &kv, Type: ty})
+	}
+	return evs
+}
+
+// notify notifies the fact that given event at the given rev just happened to
+// watchers that watch on the key of the event.
+func (s *watchableStore) notify(rev int64, evs []mvccpb.Event) {
+	victim := make(watcherBatch)
+	for w, eb := range newWatcherBatch(&s.synced, evs) {
+		if eb.revs != 1 {
+			s.store.lg.Panic(
+				"unexpected multiple revisions in watch notification",
+				zap.Int("number-of-revisions", eb.revs),
+			)
+		}
+		if w.send(WatchResponse{WatchID: w.id, Events: eb.evs, Revision: rev}) {
+			pendingEventsGauge.Add(float64(len(eb.evs)))
+		} else {
+			// move slow watcher to victims
+			w.victim = true
+			victim[w] = eb
+			s.synced.delete(w)
+			slowWatcherGauge.Inc()
+		}
+		// always update minRev
+		// in case 'send' returns true and watcher stays synced, this is needed for Restore when all watchers become unsynced
+		// in case 'send' returns false, this is needed for syncWatchers
+		w.minRev = rev + 1
+	}
+	s.addVictim(victim)
+}
+
+func (s *watchableStore) addVictim(victim watcherBatch) {
+	if len(victim) == 0 {
+		return
+	}
+	s.victims = append(s.victims, victim)
+	select {
+	case s.victimc <- struct{}{}:
+	default:
+	}
+}
+
+func (s *watchableStore) rev() int64 { return s.store.Rev() }
+
+func (s *watchableStore) progress(w *watcher) {
+	s.progressIfSync(map[WatchID]*watcher{w.id: w}, w.id)
+}
+
+func (s *watchableStore) progressAll(watchers map[WatchID]*watcher) bool {
+	return s.progressIfSync(watchers, clientv3.InvalidWatchID)
+}
+
+func (s *watchableStore) progressIfSync(watchers map[WatchID]*watcher, responseWatchID WatchID) bool {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+
+	rev := s.rev()
+	// Any watcher unsynced?
+	for _, w := range watchers {
+		if _, ok := s.synced.watchers[w]; !ok {
+			return false
+		}
+		if rev < w.startRev {
+			return false
+		}
+	}
+
+	// If all watchers are synchronised, send out progress
+	// notification on first watcher. Note that all watchers
+	// should have the same underlying stream, and the progress
+	// notification will be broadcasted client-side if required
+	// (see dispatchEvent in client/v3/watch.go)
+	for _, w := range watchers {
+		w.send(WatchResponse{WatchID: responseWatchID, Revision: rev})
+		return true
+	}
+	return true
+}
+
+type watcher struct {
+	// the watcher key
+	key []byte
+	// end indicates the end of the range to watch.
+	// If end is set, the watcher is on a range.
+	end []byte
+
+	// victim is set when ch is blocked and undergoing victim processing
+	victim bool
+
+	// compacted is set when the watcher is removed because of compaction
+	compacted bool
+
+	// restore is true when the watcher is being restored from leader snapshot
+	// which means that this watcher has just been moved from "synced" to "unsynced"
+	// watcher group, possibly with a future revision when it was first added
+	// to the synced watcher
+	// "unsynced" watcher revision must always be <= current revision,
+	// except when the watcher were to be moved from "synced" watcher group
+	restore bool
+
+	startRev int64
+	// minRev is the minimum revision update the watcher will accept
+	minRev int64
+	id     WatchID
+
+	fcs []FilterFunc
+	// a chan to send out the watch response.
+	// The chan might be shared with other watchers.
+	ch chan<- WatchResponse
+}
+
+func (w *watcher) send(wr WatchResponse) bool {
+	progressEvent := len(wr.Events) == 0
+
+	if len(w.fcs) != 0 {
+		ne := make([]mvccpb.Event, 0, len(wr.Events))
+		for i := range wr.Events {
+			filtered := false
+			for _, filter := range w.fcs {
+				if filter(wr.Events[i]) {
+					filtered = true
+					break
+				}
+			}
+			if !filtered {
+				ne = append(ne, wr.Events[i])
+			}
+		}
+		wr.Events = ne
+	}
+
+	verify.Verify(func() {
+		if w.startRev > 0 {
+			for _, ev := range wr.Events {
+				if ev.Kv.ModRevision < w.startRev {
+					panic(fmt.Sprintf("Event.ModRevision(%d) is less than the w.startRev(%d) for watchID: %d", ev.Kv.ModRevision, w.startRev, w.id))
+				}
+			}
+		}
+	})
+
+	// if all events are filtered out, we should send nothing.
+	if !progressEvent && len(wr.Events) == 0 {
+		return true
+	}
+	select {
+	case w.ch <- wr:
+		return true
+	default:
+		return false
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/watchable_store_txn.go b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/watchable_store_txn.go
new file mode 100644
index 0000000..b70d8ce
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/watchable_store_txn.go
@@ -0,0 +1,56 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package mvcc
+
+import (
+	"go.etcd.io/etcd/api/v3/mvccpb"
+	"go.etcd.io/etcd/pkg/v3/traceutil"
+)
+
+func (tw *watchableStoreTxnWrite) End() {
+	changes := tw.Changes()
+	if len(changes) == 0 {
+		tw.TxnWrite.End()
+		return
+	}
+
+	rev := tw.Rev() + 1
+	evs := make([]mvccpb.Event, len(changes))
+	for i, change := range changes {
+		evs[i].Kv = &changes[i]
+		if change.CreateRevision == 0 {
+			evs[i].Type = mvccpb.DELETE
+			evs[i].Kv.ModRevision = rev
+		} else {
+			evs[i].Type = mvccpb.PUT
+		}
+	}
+
+	// end write txn under watchable store lock so the updates are visible
+	// when asynchronous event posting checks the current store revision
+	tw.s.mu.Lock()
+	tw.s.notify(rev, evs)
+	tw.TxnWrite.End()
+	tw.s.mu.Unlock()
+}
+
+type watchableStoreTxnWrite struct {
+	TxnWrite
+	s *watchableStore
+}
+
+func (s *watchableStore) Write(trace *traceutil.Trace) TxnWrite {
+	return &watchableStoreTxnWrite{s.store.Write(trace), s}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/watcher.go b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/watcher.go
new file mode 100644
index 0000000..c67c21d
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/watcher.go
@@ -0,0 +1,203 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package mvcc
+
+import (
+	"bytes"
+	"errors"
+	"sync"
+
+	"go.etcd.io/etcd/api/v3/mvccpb"
+	clientv3 "go.etcd.io/etcd/client/v3"
+)
+
+var (
+	ErrWatcherNotExist    = errors.New("mvcc: watcher does not exist")
+	ErrEmptyWatcherRange  = errors.New("mvcc: watcher range is empty")
+	ErrWatcherDuplicateID = errors.New("mvcc: duplicate watch ID provided on the WatchStream")
+)
+
+type WatchID int64
+
+// FilterFunc returns true if the given event should be filtered out.
+type FilterFunc func(e mvccpb.Event) bool
+
+type WatchStream interface {
+	// Watch creates a watcher. The watcher watches the events happening or
+	// happened on the given key or range [key, end) from the given startRev.
+	//
+	// The whole event history can be watched unless compacted.
+	// If "startRev" <=0, watch observes events after currentRev.
+	//
+	// The returned "id" is the ID of this watcher. It appears as WatchID
+	// in events that are sent to the created watcher through stream channel.
+	// The watch ID is used when it's not equal to AutoWatchID. Otherwise,
+	// an auto-generated watch ID is returned.
+	Watch(id WatchID, key, end []byte, startRev int64, fcs ...FilterFunc) (WatchID, error)
+
+	// Chan returns a chan. All watch response will be sent to the returned chan.
+	Chan() <-chan WatchResponse
+
+	// RequestProgress requests the progress of the watcher with given ID. The response
+	// will only be sent if the watcher is currently synced.
+	// The responses will be sent through the WatchRespone Chan attached
+	// with this stream to ensure correct ordering.
+	// The responses contains no events. The revision in the response is the progress
+	// of the watchers since the watcher is currently synced.
+	RequestProgress(id WatchID)
+
+	// RequestProgressAll requests a progress notification for all
+	// watchers sharing the stream.  If all watchers are synced, a
+	// progress notification with watch ID -1 will be sent to an
+	// arbitrary watcher of this stream, and the function returns
+	// true.
+	RequestProgressAll() bool
+
+	// Cancel cancels a watcher by giving its ID. If watcher does not exist, an error will be
+	// returned.
+	Cancel(id WatchID) error
+
+	// Close closes Chan and release all related resources.
+	Close()
+
+	// Rev returns the current revision of the KV the stream watches on.
+	Rev() int64
+}
+
+type WatchResponse struct {
+	// WatchID is the WatchID of the watcher this response sent to.
+	WatchID WatchID
+
+	// Events contains all the events that needs to send.
+	Events []mvccpb.Event
+
+	// Revision is the revision of the KV when the watchResponse is created.
+	// For a normal response, the revision should be the same as the last
+	// modified revision inside Events. For a delayed response to a unsynced
+	// watcher, the revision is greater than the last modified revision
+	// inside Events.
+	Revision int64
+
+	// CompactRevision is set when the watcher is cancelled due to compaction.
+	CompactRevision int64
+}
+
+// watchStream contains a collection of watchers that share
+// one streaming chan to send out watched events and other control events.
+type watchStream struct {
+	watchable watchable
+	ch        chan WatchResponse
+
+	mu sync.Mutex // guards fields below it
+	// nextID is the ID pre-allocated for next new watcher in this stream
+	nextID   WatchID
+	closed   bool
+	cancels  map[WatchID]cancelFunc
+	watchers map[WatchID]*watcher
+}
+
+// Watch creates a new watcher in the stream and returns its WatchID.
+func (ws *watchStream) Watch(id WatchID, key, end []byte, startRev int64, fcs ...FilterFunc) (WatchID, error) {
+	// prevent wrong range where key >= end lexicographically
+	// watch request with 'WithFromKey' has empty-byte range end
+	if len(end) != 0 && bytes.Compare(key, end) != -1 {
+		return -1, ErrEmptyWatcherRange
+	}
+
+	ws.mu.Lock()
+	defer ws.mu.Unlock()
+	if ws.closed {
+		return -1, ErrEmptyWatcherRange
+	}
+
+	if id == clientv3.AutoWatchID {
+		for ws.watchers[ws.nextID] != nil {
+			ws.nextID++
+		}
+		id = ws.nextID
+		ws.nextID++
+	} else if _, ok := ws.watchers[id]; ok {
+		return -1, ErrWatcherDuplicateID
+	}
+
+	w, c := ws.watchable.watch(key, end, startRev, id, ws.ch, fcs...)
+
+	ws.cancels[id] = c
+	ws.watchers[id] = w
+	return id, nil
+}
+
+func (ws *watchStream) Chan() <-chan WatchResponse {
+	return ws.ch
+}
+
+func (ws *watchStream) Cancel(id WatchID) error {
+	ws.mu.Lock()
+	cancel, ok := ws.cancels[id]
+	w := ws.watchers[id]
+	ok = ok && !ws.closed
+	ws.mu.Unlock()
+
+	if !ok {
+		return ErrWatcherNotExist
+	}
+	cancel()
+
+	ws.mu.Lock()
+	// The watch isn't removed until cancel so that if Close() is called,
+	// it will wait for the cancel. Otherwise, Close() could close the
+	// watch channel while the store is still posting events.
+	if ww := ws.watchers[id]; ww == w {
+		delete(ws.cancels, id)
+		delete(ws.watchers, id)
+	}
+	ws.mu.Unlock()
+
+	return nil
+}
+
+func (ws *watchStream) Close() {
+	ws.mu.Lock()
+	defer ws.mu.Unlock()
+
+	for _, cancel := range ws.cancels {
+		cancel()
+	}
+	ws.closed = true
+	close(ws.ch)
+	watchStreamGauge.Dec()
+}
+
+func (ws *watchStream) Rev() int64 {
+	ws.mu.Lock()
+	defer ws.mu.Unlock()
+	return ws.watchable.rev()
+}
+
+func (ws *watchStream) RequestProgress(id WatchID) {
+	ws.mu.Lock()
+	w, ok := ws.watchers[id]
+	ws.mu.Unlock()
+	if !ok {
+		return
+	}
+	ws.watchable.progress(w)
+}
+
+func (ws *watchStream) RequestProgressAll() bool {
+	ws.mu.Lock()
+	defer ws.mu.Unlock()
+	return ws.watchable.progressAll(ws.watchers)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/watcher_group.go b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/watcher_group.go
new file mode 100644
index 0000000..c9db0e2
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/mvcc/watcher_group.go
@@ -0,0 +1,291 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package mvcc
+
+import (
+	"fmt"
+	"math"
+
+	"go.etcd.io/etcd/api/v3/mvccpb"
+	"go.etcd.io/etcd/pkg/v3/adt"
+)
+
+// watchBatchMaxRevs is the maximum distinct revisions that
+// may be sent to an unsynced watcher at a time. Declared as
+// var instead of const for testing purposes.
+var watchBatchMaxRevs = 1000
+
+type eventBatch struct {
+	// evs is a batch of revision-ordered events
+	evs []mvccpb.Event
+	// revs is the minimum unique revisions observed for this batch
+	revs int
+	// moreRev is first revision with more events following this batch
+	moreRev int64
+}
+
+func (eb *eventBatch) add(ev mvccpb.Event) {
+	if eb.revs > watchBatchMaxRevs {
+		// maxed out batch size
+		return
+	}
+
+	if len(eb.evs) == 0 {
+		// base case
+		eb.revs = 1
+		eb.evs = append(eb.evs, ev)
+		return
+	}
+
+	// revision accounting
+	ebRev := eb.evs[len(eb.evs)-1].Kv.ModRevision
+	evRev := ev.Kv.ModRevision
+	if evRev > ebRev {
+		eb.revs++
+		if eb.revs > watchBatchMaxRevs {
+			eb.moreRev = evRev
+			return
+		}
+	}
+
+	eb.evs = append(eb.evs, ev)
+}
+
+type watcherBatch map[*watcher]*eventBatch
+
+func (wb watcherBatch) add(w *watcher, ev mvccpb.Event) {
+	eb := wb[w]
+	if eb == nil {
+		eb = &eventBatch{}
+		wb[w] = eb
+	}
+	eb.add(ev)
+}
+
+// newWatcherBatch maps watchers to their matched events. It enables quick
+// events look up by watcher.
+func newWatcherBatch(wg *watcherGroup, evs []mvccpb.Event) watcherBatch {
+	if len(wg.watchers) == 0 {
+		return nil
+	}
+
+	wb := make(watcherBatch)
+	for _, ev := range evs {
+		for w := range wg.watcherSetByKey(string(ev.Kv.Key)) {
+			if ev.Kv.ModRevision >= w.minRev {
+				// don't double notify
+				wb.add(w, ev)
+			}
+		}
+	}
+	return wb
+}
+
+type watcherSet map[*watcher]struct{}
+
+func (w watcherSet) add(wa *watcher) {
+	if _, ok := w[wa]; ok {
+		panic("add watcher twice!")
+	}
+	w[wa] = struct{}{}
+}
+
+func (w watcherSet) union(ws watcherSet) {
+	for wa := range ws {
+		w.add(wa)
+	}
+}
+
+func (w watcherSet) delete(wa *watcher) {
+	if _, ok := w[wa]; !ok {
+		panic("removing missing watcher!")
+	}
+	delete(w, wa)
+}
+
+type watcherSetByKey map[string]watcherSet
+
+func (w watcherSetByKey) add(wa *watcher) {
+	set := w[string(wa.key)]
+	if set == nil {
+		set = make(watcherSet)
+		w[string(wa.key)] = set
+	}
+	set.add(wa)
+}
+
+func (w watcherSetByKey) delete(wa *watcher) bool {
+	k := string(wa.key)
+	if v, ok := w[k]; ok {
+		if _, ok := v[wa]; ok {
+			delete(v, wa)
+			if len(v) == 0 {
+				// remove the set; nothing left
+				delete(w, k)
+			}
+			return true
+		}
+	}
+	return false
+}
+
+// watcherGroup is a collection of watchers organized by their ranges
+type watcherGroup struct {
+	// keyWatchers has the watchers that watch on a single key
+	keyWatchers watcherSetByKey
+	// ranges has the watchers that watch a range; it is sorted by interval
+	ranges adt.IntervalTree
+	// watchers is the set of all watchers
+	watchers watcherSet
+}
+
+func newWatcherGroup() watcherGroup {
+	return watcherGroup{
+		keyWatchers: make(watcherSetByKey),
+		ranges:      adt.NewIntervalTree(),
+		watchers:    make(watcherSet),
+	}
+}
+
+// add puts a watcher in the group.
+func (wg *watcherGroup) add(wa *watcher) {
+	wg.watchers.add(wa)
+	if wa.end == nil {
+		wg.keyWatchers.add(wa)
+		return
+	}
+
+	// interval already registered?
+	ivl := adt.NewStringAffineInterval(string(wa.key), string(wa.end))
+	if iv := wg.ranges.Find(ivl); iv != nil {
+		iv.Val.(watcherSet).add(wa)
+		return
+	}
+
+	// not registered, put in interval tree
+	ws := make(watcherSet)
+	ws.add(wa)
+	wg.ranges.Insert(ivl, ws)
+}
+
+// contains is whether the given key has a watcher in the group.
+func (wg *watcherGroup) contains(key string) bool {
+	_, ok := wg.keyWatchers[key]
+	return ok || wg.ranges.Intersects(adt.NewStringAffinePoint(key))
+}
+
+// size gives the number of unique watchers in the group.
+func (wg *watcherGroup) size() int { return len(wg.watchers) }
+
+// delete removes a watcher from the group.
+func (wg *watcherGroup) delete(wa *watcher) bool {
+	if _, ok := wg.watchers[wa]; !ok {
+		return false
+	}
+	wg.watchers.delete(wa)
+	if wa.end == nil {
+		wg.keyWatchers.delete(wa)
+		return true
+	}
+
+	ivl := adt.NewStringAffineInterval(string(wa.key), string(wa.end))
+	iv := wg.ranges.Find(ivl)
+	if iv == nil {
+		return false
+	}
+
+	ws := iv.Val.(watcherSet)
+	delete(ws, wa)
+	if len(ws) == 0 {
+		// remove interval missing watchers
+		if ok := wg.ranges.Delete(ivl); !ok {
+			panic("could not remove watcher from interval tree")
+		}
+	}
+
+	return true
+}
+
+// choose selects watchers from the watcher group to update
+func (wg *watcherGroup) choose(maxWatchers int, curRev, compactRev int64) (*watcherGroup, int64) {
+	if len(wg.watchers) < maxWatchers {
+		return wg, wg.chooseAll(curRev, compactRev)
+	}
+	ret := newWatcherGroup()
+	for w := range wg.watchers {
+		if maxWatchers <= 0 {
+			break
+		}
+		maxWatchers--
+		ret.add(w)
+	}
+	return &ret, ret.chooseAll(curRev, compactRev)
+}
+
+func (wg *watcherGroup) chooseAll(curRev, compactRev int64) int64 {
+	minRev := int64(math.MaxInt64)
+	for w := range wg.watchers {
+		if w.minRev > curRev {
+			// after network partition, possibly choosing future revision watcher from restore operation
+			// with watch key "proxy-namespace__lostleader" and revision "math.MaxInt64 - 2"
+			// do not panic when such watcher had been moved from "synced" watcher during restore operation
+			if !w.restore {
+				panic(fmt.Errorf("watcher minimum revision %d should not exceed current revision %d", w.minRev, curRev))
+			}
+
+			// mark 'restore' done, since it's chosen
+			w.restore = false
+		}
+		if w.minRev < compactRev {
+			select {
+			case w.ch <- WatchResponse{WatchID: w.id, CompactRevision: compactRev}:
+				w.compacted = true
+				wg.delete(w)
+			default:
+				// retry next time
+			}
+			continue
+		}
+		if minRev > w.minRev {
+			minRev = w.minRev
+		}
+	}
+	return minRev
+}
+
+// watcherSetByKey gets the set of watchers that receive events on the given key.
+func (wg *watcherGroup) watcherSetByKey(key string) watcherSet {
+	wkeys := wg.keyWatchers[key]
+	wranges := wg.ranges.Stab(adt.NewStringAffinePoint(key))
+
+	// zero-copy cases
+	switch {
+	case len(wranges) == 0:
+		// no need to merge ranges or copy; reuse single-key set
+		return wkeys
+	case len(wranges) == 0 && len(wkeys) == 0:
+		return nil
+	case len(wranges) == 1 && len(wkeys) == 0:
+		return wranges[0].Val.(watcherSet)
+	}
+
+	// copy case
+	ret := make(watcherSet)
+	ret.union(wg.keyWatchers[key])
+	for _, item := range wranges {
+		ret.union(item.Val.(watcherSet))
+	}
+	return ret
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/quota.go b/vendor/go.etcd.io/etcd/server/v3/storage/quota.go
new file mode 100644
index 0000000..f9ff72d
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/quota.go
@@ -0,0 +1,176 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package storage
+
+import (
+	"sync"
+
+	humanize "github.com/dustin/go-humanize"
+	"go.uber.org/zap"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/server/v3/storage/backend"
+)
+
+const (
+	// DefaultQuotaBytes is the number of bytes the backend Size may
+	// consume before exceeding the space quota.
+	DefaultQuotaBytes = int64(2 * 1024 * 1024 * 1024) // 2GB
+	// MaxQuotaBytes is the maximum number of bytes suggested for a backend
+	// quota. A larger quota may lead to degraded performance.
+	MaxQuotaBytes = int64(8 * 1024 * 1024 * 1024) // 8GB
+)
+
+// Quota represents an arbitrary quota against arbitrary requests. Each request
+// costs some charge; if there is not enough remaining charge, then there are
+// too few resources available within the quota to apply the request.
+type Quota interface {
+	// Available judges whether the given request fits within the quota.
+	Available(req any) bool
+	// Cost computes the charge against the quota for a given request.
+	Cost(req any) int
+	// Remaining is the amount of charge left for the quota.
+	Remaining() int64
+}
+
+type passthroughQuota struct{}
+
+func (*passthroughQuota) Available(any) bool { return true }
+func (*passthroughQuota) Cost(any) int       { return 0 }
+func (*passthroughQuota) Remaining() int64   { return 1 }
+
+type BackendQuota struct {
+	be              backend.Backend
+	maxBackendBytes int64
+}
+
+const (
+	// leaseOverhead is an estimate for the cost of storing a lease
+	leaseOverhead = 64
+	// kvOverhead is an estimate for the cost of storing a key's Metadata
+	kvOverhead = 256
+)
+
+var (
+	// only log once
+	quotaLogOnce sync.Once
+
+	DefaultQuotaSize = humanize.Bytes(uint64(DefaultQuotaBytes))
+	maxQuotaSize     = humanize.Bytes(uint64(MaxQuotaBytes))
+)
+
+// NewBackendQuota creates a quota layer with the given storage limit.
+func NewBackendQuota(lg *zap.Logger, quotaBackendBytesCfg int64, be backend.Backend, name string) Quota {
+	quotaBackendBytes.Set(float64(quotaBackendBytesCfg))
+	if quotaBackendBytesCfg < 0 {
+		// disable quotas if negative
+		quotaLogOnce.Do(func() {
+			lg.Info(
+				"disabled backend quota",
+				zap.String("quota-name", name),
+				zap.Int64("quota-size-bytes", quotaBackendBytesCfg),
+			)
+		})
+		return &passthroughQuota{}
+	}
+
+	if quotaBackendBytesCfg == 0 {
+		// use default size if no quota size given
+		quotaLogOnce.Do(func() {
+			if lg != nil {
+				lg.Info(
+					"enabled backend quota with default value",
+					zap.String("quota-name", name),
+					zap.Int64("quota-size-bytes", DefaultQuotaBytes),
+					zap.String("quota-size", DefaultQuotaSize),
+				)
+			}
+		})
+		quotaBackendBytes.Set(float64(DefaultQuotaBytes))
+		return &BackendQuota{be, DefaultQuotaBytes}
+	}
+
+	quotaLogOnce.Do(func() {
+		if quotaBackendBytesCfg > MaxQuotaBytes {
+			lg.Warn(
+				"quota exceeds the maximum value",
+				zap.String("quota-name", name),
+				zap.Int64("quota-size-bytes", quotaBackendBytesCfg),
+				zap.String("quota-size", humanize.Bytes(uint64(quotaBackendBytesCfg))),
+				zap.Int64("quota-maximum-size-bytes", MaxQuotaBytes),
+				zap.String("quota-maximum-size", maxQuotaSize),
+			)
+		}
+		lg.Info(
+			"enabled backend quota",
+			zap.String("quota-name", name),
+			zap.Int64("quota-size-bytes", quotaBackendBytesCfg),
+			zap.String("quota-size", humanize.Bytes(uint64(quotaBackendBytesCfg))),
+		)
+	})
+	return &BackendQuota{be, quotaBackendBytesCfg}
+}
+
+func (b *BackendQuota) Available(v any) bool {
+	cost := b.Cost(v)
+	// if there are no mutating requests, it's safe to pass through
+	if cost == 0 {
+		return true
+	}
+	// TODO: maybe optimize Backend.Size()
+	return b.be.Size()+int64(cost) < b.maxBackendBytes
+}
+
+func (b *BackendQuota) Cost(v any) int {
+	switch r := v.(type) {
+	case *pb.PutRequest:
+		return costPut(r)
+	case *pb.TxnRequest:
+		return costTxn(r)
+	case *pb.LeaseGrantRequest:
+		return leaseOverhead
+	default:
+		panic("unexpected cost")
+	}
+}
+
+func costPut(r *pb.PutRequest) int { return kvOverhead + len(r.Key) + len(r.Value) }
+
+func costTxnReq(u *pb.RequestOp) int {
+	r := u.GetRequestPut()
+	if r == nil {
+		return 0
+	}
+	return costPut(r)
+}
+
+func costTxn(r *pb.TxnRequest) int {
+	sizeSuccess := 0
+	for _, u := range r.Success {
+		sizeSuccess += costTxnReq(u)
+	}
+	sizeFailure := 0
+	for _, u := range r.Failure {
+		sizeFailure += costTxnReq(u)
+	}
+	if sizeFailure > sizeSuccess {
+		return sizeFailure
+	}
+	return sizeSuccess
+}
+
+func (b *BackendQuota) Remaining() int64 {
+	return b.maxBackendBytes - b.be.Size()
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/schema/actions.go b/vendor/go.etcd.io/etcd/server/v3/storage/schema/actions.go
new file mode 100644
index 0000000..8d18cee
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/schema/actions.go
@@ -0,0 +1,93 @@
+// Copyright 2021 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package schema
+
+import (
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/server/v3/storage/backend"
+)
+
+type action interface {
+	// unsafeDo executes the action and returns revert action, when executed
+	// should restore the state from before.
+	unsafeDo(tx backend.UnsafeReadWriter) (revert action, err error)
+}
+
+type setKeyAction struct {
+	Bucket     backend.Bucket
+	FieldName  []byte
+	FieldValue []byte
+}
+
+func (a setKeyAction) unsafeDo(tx backend.UnsafeReadWriter) (action, error) {
+	revert := restoreFieldValueAction(tx, a.Bucket, a.FieldName)
+	tx.UnsafePut(a.Bucket, a.FieldName, a.FieldValue)
+	return revert, nil
+}
+
+type deleteKeyAction struct {
+	Bucket    backend.Bucket
+	FieldName []byte
+}
+
+func (a deleteKeyAction) unsafeDo(tx backend.UnsafeReadWriter) (action, error) {
+	revert := restoreFieldValueAction(tx, a.Bucket, a.FieldName)
+	tx.UnsafeDelete(a.Bucket, a.FieldName)
+	return revert, nil
+}
+
+func restoreFieldValueAction(tx backend.UnsafeReader, bucket backend.Bucket, fieldName []byte) action {
+	_, vs := tx.UnsafeRange(bucket, fieldName, nil, 1)
+	if len(vs) == 1 {
+		return &setKeyAction{
+			Bucket:     bucket,
+			FieldName:  fieldName,
+			FieldValue: vs[0],
+		}
+	}
+	return &deleteKeyAction{
+		Bucket:    bucket,
+		FieldName: fieldName,
+	}
+}
+
+type ActionList []action
+
+// unsafeExecute executes actions one by one. If one of actions returns error,
+// it will revert them.
+func (as ActionList) unsafeExecute(lg *zap.Logger, tx backend.UnsafeReadWriter) error {
+	revertActions := make(ActionList, 0, len(as))
+	for _, a := range as {
+		revert, err := a.unsafeDo(tx)
+		if err != nil {
+			revertActions.unsafeExecuteInReversedOrder(lg, tx)
+			return err
+		}
+		revertActions = append(revertActions, revert)
+	}
+	return nil
+}
+
+// unsafeExecuteInReversedOrder executes actions in revered order. Will panic on
+// action error. Should be used when reverting.
+func (as ActionList) unsafeExecuteInReversedOrder(lg *zap.Logger, tx backend.UnsafeReadWriter) {
+	for j := len(as) - 1; j >= 0; j-- {
+		_, err := as[j].unsafeDo(tx)
+		if err != nil {
+			lg.Panic("Cannot recover from revert error", zap.Error(err))
+		}
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/schema/alarm.go b/vendor/go.etcd.io/etcd/server/v3/storage/schema/alarm.go
new file mode 100644
index 0000000..929fbd4
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/schema/alarm.go
@@ -0,0 +1,105 @@
+// Copyright 2021 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package schema
+
+import (
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/server/v3/storage/backend"
+)
+
+type AlarmBackend interface {
+	CreateAlarmBucket()
+	MustPutAlarm(member *etcdserverpb.AlarmMember)
+	MustDeleteAlarm(alarm *etcdserverpb.AlarmMember)
+	GetAllAlarms() ([]*etcdserverpb.AlarmMember, error)
+	ForceCommit()
+}
+
+type alarmBackend struct {
+	lg *zap.Logger
+	be backend.Backend
+}
+
+func NewAlarmBackend(lg *zap.Logger, be backend.Backend) AlarmBackend {
+	return &alarmBackend{
+		lg: lg,
+		be: be,
+	}
+}
+
+func (s *alarmBackend) CreateAlarmBucket() {
+	tx := s.be.BatchTx()
+	tx.LockOutsideApply()
+	defer tx.Unlock()
+	tx.UnsafeCreateBucket(Alarm)
+}
+
+func (s *alarmBackend) MustPutAlarm(alarm *etcdserverpb.AlarmMember) {
+	tx := s.be.BatchTx()
+	tx.LockInsideApply()
+	defer tx.Unlock()
+	s.mustUnsafePutAlarm(tx, alarm)
+}
+
+func (s *alarmBackend) mustUnsafePutAlarm(tx backend.UnsafeWriter, alarm *etcdserverpb.AlarmMember) {
+	v, err := alarm.Marshal()
+	if err != nil {
+		s.lg.Panic("failed to marshal alarm member", zap.Error(err))
+	}
+
+	tx.UnsafePut(Alarm, v, nil)
+}
+
+func (s *alarmBackend) MustDeleteAlarm(alarm *etcdserverpb.AlarmMember) {
+	tx := s.be.BatchTx()
+	tx.LockInsideApply()
+	defer tx.Unlock()
+	s.mustUnsafeDeleteAlarm(tx, alarm)
+}
+
+func (s *alarmBackend) mustUnsafeDeleteAlarm(tx backend.UnsafeWriter, alarm *etcdserverpb.AlarmMember) {
+	v, err := alarm.Marshal()
+	if err != nil {
+		s.lg.Panic("failed to marshal alarm member", zap.Error(err))
+	}
+
+	tx.UnsafeDelete(Alarm, v)
+}
+
+func (s *alarmBackend) GetAllAlarms() ([]*etcdserverpb.AlarmMember, error) {
+	tx := s.be.ReadTx()
+	tx.RLock()
+	defer tx.RUnlock()
+	return s.unsafeGetAllAlarms(tx)
+}
+
+func (s *alarmBackend) unsafeGetAllAlarms(tx backend.UnsafeReader) ([]*etcdserverpb.AlarmMember, error) {
+	var ms []*etcdserverpb.AlarmMember
+	err := tx.UnsafeForEach(Alarm, func(k, v []byte) error {
+		var m etcdserverpb.AlarmMember
+		if err := m.Unmarshal(k); err != nil {
+			return err
+		}
+		ms = append(ms, &m)
+		return nil
+	})
+	return ms, err
+}
+
+func (s alarmBackend) ForceCommit() {
+	s.be.ForceCommit()
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/schema/auth.go b/vendor/go.etcd.io/etcd/server/v3/storage/schema/auth.go
new file mode 100644
index 0000000..b91b6eb
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/schema/auth.go
@@ -0,0 +1,152 @@
+// Copyright 2021 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package schema
+
+import (
+	"bytes"
+	"encoding/binary"
+
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/server/v3/auth"
+	"go.etcd.io/etcd/server/v3/storage/backend"
+)
+
+const (
+	revBytesLen = 8
+)
+
+var (
+	authEnabled  = []byte{1}
+	authDisabled = []byte{0}
+)
+
+type authBackend struct {
+	be backend.Backend
+	lg *zap.Logger
+}
+
+var _ auth.AuthBackend = (*authBackend)(nil)
+
+func NewAuthBackend(lg *zap.Logger, be backend.Backend) auth.AuthBackend {
+	return &authBackend{
+		be: be,
+		lg: lg,
+	}
+}
+
+func (abe *authBackend) CreateAuthBuckets() {
+	tx := abe.be.BatchTx()
+	tx.LockOutsideApply()
+	defer tx.Unlock()
+	tx.UnsafeCreateBucket(Auth)
+	tx.UnsafeCreateBucket(AuthUsers)
+	tx.UnsafeCreateBucket(AuthRoles)
+}
+
+func (abe *authBackend) ForceCommit() {
+	abe.be.ForceCommit()
+}
+
+func (abe *authBackend) ReadTx() auth.AuthReadTx {
+	return &authReadTx{tx: abe.be.ReadTx(), lg: abe.lg}
+}
+
+func (abe *authBackend) BatchTx() auth.AuthBatchTx {
+	return &authBatchTx{tx: abe.be.BatchTx(), lg: abe.lg}
+}
+
+type authReadTx struct {
+	tx backend.ReadTx
+	lg *zap.Logger
+}
+
+type authBatchTx struct {
+	tx backend.BatchTx
+	lg *zap.Logger
+}
+
+var (
+	_ auth.AuthReadTx  = (*authReadTx)(nil)
+	_ auth.AuthBatchTx = (*authBatchTx)(nil)
+)
+
+func (atx *authBatchTx) UnsafeSaveAuthEnabled(enabled bool) {
+	if enabled {
+		atx.tx.UnsafePut(Auth, AuthEnabledKeyName, authEnabled)
+	} else {
+		atx.tx.UnsafePut(Auth, AuthEnabledKeyName, authDisabled)
+	}
+}
+
+func (atx *authBatchTx) UnsafeSaveAuthRevision(rev uint64) {
+	revBytes := make([]byte, revBytesLen)
+	binary.BigEndian.PutUint64(revBytes, rev)
+	atx.tx.UnsafePut(Auth, AuthRevisionKeyName, revBytes)
+}
+
+func (atx *authBatchTx) UnsafeReadAuthEnabled() bool {
+	return unsafeReadAuthEnabled(atx.tx)
+}
+
+func (atx *authBatchTx) UnsafeReadAuthRevision() uint64 {
+	return unsafeReadAuthRevision(atx.tx)
+}
+
+func (atx *authBatchTx) Lock() {
+	atx.tx.LockInsideApply()
+}
+
+func (atx *authBatchTx) Unlock() {
+	atx.tx.Unlock()
+	// Calling Commit() for defensive purpose. If the number of pending writes doesn't exceed batchLimit,
+	// ReadTx can miss some writes issued by its predecessor BatchTx.
+	atx.tx.Commit()
+}
+
+func (atx *authReadTx) UnsafeReadAuthEnabled() bool {
+	return unsafeReadAuthEnabled(atx.tx)
+}
+
+func unsafeReadAuthEnabled(tx backend.UnsafeReader) bool {
+	_, vs := tx.UnsafeRange(Auth, AuthEnabledKeyName, nil, 0)
+	if len(vs) == 1 {
+		if bytes.Equal(vs[0], authEnabled) {
+			return true
+		}
+	}
+	return false
+}
+
+func (atx *authReadTx) UnsafeReadAuthRevision() uint64 {
+	return unsafeReadAuthRevision(atx.tx)
+}
+
+func unsafeReadAuthRevision(tx backend.UnsafeReader) uint64 {
+	_, vs := tx.UnsafeRange(Auth, AuthRevisionKeyName, nil, 0)
+	if len(vs) != 1 {
+		// this can happen in the initialization phase
+		return 0
+	}
+	return binary.BigEndian.Uint64(vs[0])
+}
+
+func (atx *authReadTx) RLock() {
+	atx.tx.RLock()
+}
+
+func (atx *authReadTx) RUnlock() {
+	atx.tx.RUnlock()
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/schema/auth_roles.go b/vendor/go.etcd.io/etcd/server/v3/storage/schema/auth_roles.go
new file mode 100644
index 0000000..6161a08
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/schema/auth_roles.go
@@ -0,0 +1,105 @@
+// Copyright 2021 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package schema
+
+import (
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/api/v3/authpb"
+	"go.etcd.io/etcd/server/v3/storage/backend"
+)
+
+func UnsafeCreateAuthRolesBucket(tx backend.UnsafeWriter) {
+	tx.UnsafeCreateBucket(AuthRoles)
+}
+
+func (abe *authBackend) GetRole(roleName string) *authpb.Role {
+	tx := abe.ReadTx()
+	tx.RLock()
+	defer tx.RUnlock()
+	return tx.UnsafeGetRole(roleName)
+}
+
+func (atx *authBatchTx) UnsafeGetRole(roleName string) *authpb.Role {
+	return unsafeGetRole(atx.lg, atx.tx, roleName)
+}
+
+func (abe *authBackend) GetAllRoles() []*authpb.Role {
+	tx := abe.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+	return tx.UnsafeGetAllRoles()
+}
+
+func (atx *authBatchTx) UnsafeGetAllRoles() []*authpb.Role {
+	return unsafeGetAllRoles(atx.lg, atx.tx)
+}
+
+func (atx *authBatchTx) UnsafePutRole(role *authpb.Role) {
+	b, err := role.Marshal()
+	if err != nil {
+		atx.lg.Panic(
+			"failed to marshal 'authpb.Role'",
+			zap.String("role-name", string(role.Name)),
+			zap.Error(err),
+		)
+	}
+
+	atx.tx.UnsafePut(AuthRoles, role.Name, b)
+}
+
+func (atx *authBatchTx) UnsafeDeleteRole(rolename string) {
+	atx.tx.UnsafeDelete(AuthRoles, []byte(rolename))
+}
+
+func (atx *authReadTx) UnsafeGetRole(roleName string) *authpb.Role {
+	return unsafeGetRole(atx.lg, atx.tx, roleName)
+}
+
+func unsafeGetRole(lg *zap.Logger, tx backend.UnsafeReader, roleName string) *authpb.Role {
+	_, vs := tx.UnsafeRange(AuthRoles, []byte(roleName), nil, 0)
+	if len(vs) == 0 {
+		return nil
+	}
+
+	role := &authpb.Role{}
+	err := role.Unmarshal(vs[0])
+	if err != nil {
+		lg.Panic("failed to unmarshal 'authpb.Role'", zap.Error(err))
+	}
+	return role
+}
+
+func (atx *authReadTx) UnsafeGetAllRoles() []*authpb.Role {
+	return unsafeGetAllRoles(atx.lg, atx.tx)
+}
+
+func unsafeGetAllRoles(lg *zap.Logger, tx backend.UnsafeReader) []*authpb.Role {
+	_, vs := tx.UnsafeRange(AuthRoles, []byte{0}, []byte{0xff}, -1)
+	if len(vs) == 0 {
+		return nil
+	}
+
+	roles := make([]*authpb.Role, len(vs))
+	for i := range vs {
+		role := &authpb.Role{}
+		err := role.Unmarshal(vs[i])
+		if err != nil {
+			lg.Panic("failed to unmarshal 'authpb.Role'", zap.Error(err))
+		}
+		roles[i] = role
+	}
+	return roles
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/schema/auth_users.go b/vendor/go.etcd.io/etcd/server/v3/storage/schema/auth_users.go
new file mode 100644
index 0000000..c21fa7c
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/schema/auth_users.go
@@ -0,0 +1,108 @@
+// Copyright 2021 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package schema
+
+import (
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/api/v3/authpb"
+	"go.etcd.io/etcd/server/v3/storage/backend"
+)
+
+func (abe *authBackend) GetUser(username string) *authpb.User {
+	tx := abe.ReadTx()
+	tx.RLock()
+	defer tx.RUnlock()
+	return tx.UnsafeGetUser(username)
+}
+
+func (atx *authBatchTx) UnsafeGetUser(username string) *authpb.User {
+	return unsafeGetUser(atx.lg, atx.tx, username)
+}
+
+func (atx *authBatchTx) UnsafeGetAllUsers() []*authpb.User {
+	return unsafeGetAllUsers(atx.lg, atx.tx)
+}
+
+func (atx *authBatchTx) UnsafePutUser(user *authpb.User) {
+	b, err := user.Marshal()
+	if err != nil {
+		atx.lg.Panic("failed to unmarshal 'authpb.User'", zap.Error(err))
+	}
+	atx.tx.UnsafePut(AuthUsers, user.Name, b)
+}
+
+func (atx *authBatchTx) UnsafeDeleteUser(username string) {
+	atx.tx.UnsafeDelete(AuthUsers, []byte(username))
+}
+
+func (atx *authReadTx) UnsafeGetUser(username string) *authpb.User {
+	return unsafeGetUser(atx.lg, atx.tx, username)
+}
+
+func unsafeGetUser(lg *zap.Logger, tx backend.UnsafeReader, username string) *authpb.User {
+	_, vs := tx.UnsafeRange(AuthUsers, []byte(username), nil, 0)
+	if len(vs) == 0 {
+		return nil
+	}
+
+	user := &authpb.User{}
+	err := user.Unmarshal(vs[0])
+	if err != nil {
+		lg.Panic(
+			"failed to unmarshal 'authpb.User'",
+			zap.String("user-name", username),
+			zap.Error(err),
+		)
+	}
+	return user
+}
+
+func (abe *authBackend) GetAllUsers() []*authpb.User {
+	tx := abe.ReadTx()
+	tx.RLock()
+	defer tx.RUnlock()
+	return tx.UnsafeGetAllUsers()
+}
+
+func (atx *authReadTx) UnsafeGetAllUsers() []*authpb.User {
+	return unsafeGetAllUsers(atx.lg, atx.tx)
+}
+
+func unsafeGetAllUsers(lg *zap.Logger, tx backend.UnsafeReader) []*authpb.User {
+	var vs [][]byte
+	err := tx.UnsafeForEach(AuthUsers, func(k []byte, v []byte) error {
+		vs = append(vs, v)
+		return nil
+	})
+	if err != nil {
+		lg.Panic("failed to get users",
+			zap.Error(err))
+	}
+	if len(vs) == 0 {
+		return nil
+	}
+
+	users := make([]*authpb.User, len(vs))
+	for i := range vs {
+		user := &authpb.User{}
+		err := user.Unmarshal(vs[i])
+		if err != nil {
+			lg.Panic("failed to unmarshal 'authpb.User'", zap.Error(err))
+		}
+		users[i] = user
+	}
+	return users
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/schema/bucket.go b/vendor/go.etcd.io/etcd/server/v3/storage/schema/bucket.go
new file mode 100644
index 0000000..06da660
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/schema/bucket.go
@@ -0,0 +1,100 @@
+// Copyright 2021 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package schema
+
+import (
+	"bytes"
+
+	"go.etcd.io/etcd/client/pkg/v3/types"
+	"go.etcd.io/etcd/server/v3/storage/backend"
+)
+
+var (
+	keyBucketName   = []byte("key")
+	metaBucketName  = []byte("meta")
+	leaseBucketName = []byte("lease")
+	alarmBucketName = []byte("alarm")
+
+	clusterBucketName = []byte("cluster")
+
+	membersBucketName        = []byte("members")
+	membersRemovedBucketName = []byte("members_removed")
+
+	authBucketName      = []byte("auth")
+	authUsersBucketName = []byte("authUsers")
+	authRolesBucketName = []byte("authRoles")
+
+	testBucketName = []byte("test")
+)
+
+var (
+	Key     = backend.Bucket(bucket{id: 1, name: keyBucketName, safeRangeBucket: true})
+	Meta    = backend.Bucket(bucket{id: 2, name: metaBucketName, safeRangeBucket: false})
+	Lease   = backend.Bucket(bucket{id: 3, name: leaseBucketName, safeRangeBucket: false})
+	Alarm   = backend.Bucket(bucket{id: 4, name: alarmBucketName, safeRangeBucket: false})
+	Cluster = backend.Bucket(bucket{id: 5, name: clusterBucketName, safeRangeBucket: false})
+
+	Members        = backend.Bucket(bucket{id: 10, name: membersBucketName, safeRangeBucket: false})
+	MembersRemoved = backend.Bucket(bucket{id: 11, name: membersRemovedBucketName, safeRangeBucket: false})
+
+	Auth      = backend.Bucket(bucket{id: 20, name: authBucketName, safeRangeBucket: false})
+	AuthUsers = backend.Bucket(bucket{id: 21, name: authUsersBucketName, safeRangeBucket: false})
+	AuthRoles = backend.Bucket(bucket{id: 22, name: authRolesBucketName, safeRangeBucket: false})
+
+	Test = backend.Bucket(bucket{id: 100, name: testBucketName, safeRangeBucket: false})
+
+	AllBuckets = []backend.Bucket{Key, Meta, Lease, Alarm, Cluster, Members, MembersRemoved, Auth, AuthUsers, AuthRoles}
+)
+
+type bucket struct {
+	id              backend.BucketID
+	name            []byte
+	safeRangeBucket bool
+}
+
+func (b bucket) ID() backend.BucketID    { return b.id }
+func (b bucket) Name() []byte            { return b.name }
+func (b bucket) String() string          { return string(b.Name()) }
+func (b bucket) IsSafeRangeBucket() bool { return b.safeRangeBucket }
+
+var (
+	// Pre v3.5
+	ScheduledCompactKeyName    = []byte("scheduledCompactRev")
+	FinishedCompactKeyName     = []byte("finishedCompactRev")
+	MetaConsistentIndexKeyName = []byte("consistent_index")
+	AuthEnabledKeyName         = []byte("authEnabled")
+	AuthRevisionKeyName        = []byte("authRevision")
+	// Since v3.5
+	MetaTermKeyName              = []byte("term")
+	MetaConfStateName            = []byte("confState")
+	ClusterClusterVersionKeyName = []byte("clusterVersion")
+	ClusterDowngradeKeyName      = []byte("downgrade")
+	// Since v3.6
+	MetaStorageVersionName = []byte("storageVersion")
+	// Before adding new meta key please update server/etcdserver/version
+)
+
+// DefaultIgnores defines buckets & keys to ignore in hash checking.
+func DefaultIgnores(bucket, key []byte) bool {
+	// consistent index & term might be changed due to v2 internal sync, which
+	// is not controllable by the user.
+	// storage version might change after wal snapshot and is not controller by user.
+	return bytes.Equal(bucket, Meta.Name()) &&
+		(bytes.Equal(key, MetaTermKeyName) || bytes.Equal(key, MetaConsistentIndexKeyName) || bytes.Equal(key, MetaStorageVersionName))
+}
+
+func BackendMemberKey(id types.ID) []byte {
+	return []byte(id.String())
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/schema/changes.go b/vendor/go.etcd.io/etcd/server/v3/storage/schema/changes.go
new file mode 100644
index 0000000..6eb0b75
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/schema/changes.go
@@ -0,0 +1,50 @@
+// Copyright 2021 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package schema
+
+import "go.etcd.io/etcd/server/v3/storage/backend"
+
+type schemaChange interface {
+	upgradeAction() action
+	downgradeAction() action
+}
+
+// addNewField represents adding new field when upgrading. Downgrade will remove the field.
+func addNewField(bucket backend.Bucket, fieldName []byte, fieldValue []byte) schemaChange {
+	return simpleSchemaChange{
+		upgrade: setKeyAction{
+			Bucket:     bucket,
+			FieldName:  fieldName,
+			FieldValue: fieldValue,
+		},
+		downgrade: deleteKeyAction{
+			Bucket:    bucket,
+			FieldName: fieldName,
+		},
+	}
+}
+
+type simpleSchemaChange struct {
+	upgrade   action
+	downgrade action
+}
+
+func (c simpleSchemaChange) upgradeAction() action {
+	return c.upgrade
+}
+
+func (c simpleSchemaChange) downgradeAction() action {
+	return c.downgrade
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/schema/cindex.go b/vendor/go.etcd.io/etcd/server/v3/storage/schema/cindex.go
new file mode 100644
index 0000000..cdf938d
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/schema/cindex.go
@@ -0,0 +1,95 @@
+// Copyright 2021 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package schema
+
+import (
+	"encoding/binary"
+	"fmt"
+
+	"go.etcd.io/etcd/client/pkg/v3/verify"
+	"go.etcd.io/etcd/server/v3/storage/backend"
+)
+
+// UnsafeCreateMetaBucket creates the `meta` bucket (if it does not exist yet).
+func UnsafeCreateMetaBucket(tx backend.UnsafeWriter) {
+	tx.UnsafeCreateBucket(Meta)
+}
+
+// CreateMetaBucket creates the `meta` bucket (if it does not exist yet).
+func CreateMetaBucket(tx backend.BatchTx) {
+	tx.LockOutsideApply()
+	defer tx.Unlock()
+	tx.UnsafeCreateBucket(Meta)
+}
+
+// UnsafeReadConsistentIndex loads consistent index & term from given transaction.
+// returns 0,0 if the data are not found.
+// Term is persisted since v3.5.
+func UnsafeReadConsistentIndex(tx backend.UnsafeReader) (uint64, uint64) {
+	_, vs := tx.UnsafeRange(Meta, MetaConsistentIndexKeyName, nil, 0)
+	if len(vs) == 0 {
+		return 0, 0
+	}
+	v := binary.BigEndian.Uint64(vs[0])
+	_, ts := tx.UnsafeRange(Meta, MetaTermKeyName, nil, 0)
+	if len(ts) == 0 {
+		return v, 0
+	}
+	t := binary.BigEndian.Uint64(ts[0])
+	return v, t
+}
+
+// ReadConsistentIndex loads consistent index and term from given transaction.
+// returns 0 if the data are not found.
+func ReadConsistentIndex(tx backend.ReadTx) (uint64, uint64) {
+	tx.RLock()
+	defer tx.RUnlock()
+	return UnsafeReadConsistentIndex(tx)
+}
+
+func UnsafeUpdateConsistentIndexForce(tx backend.UnsafeReadWriter, index uint64, term uint64) {
+	unsafeUpdateConsistentIndex(tx, index, term, true)
+}
+
+func UnsafeUpdateConsistentIndex(tx backend.UnsafeReadWriter, index uint64, term uint64) {
+	unsafeUpdateConsistentIndex(tx, index, term, false)
+}
+
+func unsafeUpdateConsistentIndex(tx backend.UnsafeReadWriter, index uint64, term uint64, allowDecreasing bool) {
+	if index == 0 {
+		// Never save 0 as it means that we didn't load the real index yet.
+		return
+	}
+	bs1 := make([]byte, 8)
+	binary.BigEndian.PutUint64(bs1, index)
+
+	if !allowDecreasing {
+		verify.Verify(func() {
+			previousIndex, _ := UnsafeReadConsistentIndex(tx)
+			if index < previousIndex {
+				panic(fmt.Errorf("update of consistent index not advancing: previous: %v new: %v", previousIndex, index))
+			}
+		})
+	}
+
+	// put the index into the underlying backend
+	// tx has been locked in TxnBegin, so there is no need to lock it again
+	tx.UnsafePut(Meta, MetaConsistentIndexKeyName, bs1)
+	if term > 0 {
+		bs2 := make([]byte, 8)
+		binary.BigEndian.PutUint64(bs2, term)
+		tx.UnsafePut(Meta, MetaTermKeyName, bs2)
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/schema/confstate.go b/vendor/go.etcd.io/etcd/server/v3/storage/schema/confstate.go
new file mode 100644
index 0000000..c2bcb54
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/schema/confstate.go
@@ -0,0 +1,59 @@
+// Copyright 2021 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package schema
+
+import (
+	"encoding/json"
+	"log"
+
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/server/v3/storage/backend"
+	"go.etcd.io/raft/v3/raftpb"
+)
+
+// MustUnsafeSaveConfStateToBackend persists confState using given transaction (tx).
+// confState in backend is persisted since etcd v3.5.
+func MustUnsafeSaveConfStateToBackend(lg *zap.Logger, tx backend.UnsafeWriter, confState *raftpb.ConfState) {
+	confStateBytes, err := json.Marshal(confState)
+	if err != nil {
+		lg.Panic("Cannot marshal raftpb.ConfState", zap.Stringer("conf-state", confState), zap.Error(err))
+	}
+
+	tx.UnsafePut(Meta, MetaConfStateName, confStateBytes)
+}
+
+// UnsafeConfStateFromBackend retrieves ConfState from the backend.
+// Returns nil if confState in backend is not persisted (e.g. backend written by <v3.5).
+func UnsafeConfStateFromBackend(lg *zap.Logger, tx backend.UnsafeReader) *raftpb.ConfState {
+	keys, vals := tx.UnsafeRange(Meta, MetaConfStateName, nil, 0)
+	if len(keys) == 0 {
+		return nil
+	}
+
+	if len(keys) != 1 {
+		lg.Panic(
+			"unexpected number of key: "+string(MetaConfStateName)+" when getting cluster version from backend",
+			zap.Int("number-of-key", len(keys)),
+		)
+	}
+	var confState raftpb.ConfState
+	if err := json.Unmarshal(vals[0], &confState); err != nil {
+		log.Panic("Cannot unmarshal confState json retrieved from the backend",
+			zap.ByteString("conf-state-json", vals[0]),
+			zap.Error(err))
+	}
+	return &confState
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/schema/lease.go b/vendor/go.etcd.io/etcd/server/v3/storage/schema/lease.go
new file mode 100644
index 0000000..de29f30
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/schema/lease.go
@@ -0,0 +1,84 @@
+// Copyright 2021 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package schema
+
+import (
+	"encoding/binary"
+	"fmt"
+
+	"go.etcd.io/etcd/server/v3/lease/leasepb"
+	"go.etcd.io/etcd/server/v3/storage/backend"
+)
+
+func UnsafeCreateLeaseBucket(tx backend.UnsafeWriter) {
+	tx.UnsafeCreateBucket(Lease)
+}
+
+func MustUnsafeGetAllLeases(tx backend.UnsafeReader) []*leasepb.Lease {
+	ls := make([]*leasepb.Lease, 0)
+	err := tx.UnsafeForEach(Lease, func(k, v []byte) error {
+		var lpb leasepb.Lease
+		err := lpb.Unmarshal(v)
+		if err != nil {
+			return fmt.Errorf("failed to Unmarshal lease proto item; lease ID=%016x", bytesToLeaseID(k))
+		}
+		ls = append(ls, &lpb)
+		return nil
+	})
+	if err != nil {
+		panic(err)
+	}
+	return ls
+}
+
+func MustUnsafePutLease(tx backend.UnsafeWriter, lpb *leasepb.Lease) {
+	key := leaseIDToBytes(lpb.ID)
+
+	val, err := lpb.Marshal()
+	if err != nil {
+		panic("failed to marshal lease proto item")
+	}
+	tx.UnsafePut(Lease, key, val)
+}
+
+func UnsafeDeleteLease(tx backend.UnsafeWriter, lpb *leasepb.Lease) {
+	tx.UnsafeDelete(Lease, leaseIDToBytes(lpb.ID))
+}
+
+func MustUnsafeGetLease(tx backend.UnsafeReader, leaseID int64) *leasepb.Lease {
+	_, vs := tx.UnsafeRange(Lease, leaseIDToBytes(leaseID), nil, 0)
+	if len(vs) != 1 {
+		return nil
+	}
+	var lpb leasepb.Lease
+	err := lpb.Unmarshal(vs[0])
+	if err != nil {
+		panic("failed to unmarshal lease proto item")
+	}
+	return &lpb
+}
+
+func leaseIDToBytes(n int64) []byte {
+	bytes := make([]byte, 8)
+	binary.BigEndian.PutUint64(bytes, uint64(n))
+	return bytes
+}
+
+func bytesToLeaseID(bytes []byte) int64 {
+	if len(bytes) != 8 {
+		panic(fmt.Errorf("lease ID must be 8-byte"))
+	}
+	return int64(binary.BigEndian.Uint64(bytes))
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/schema/membership.go b/vendor/go.etcd.io/etcd/server/v3/storage/schema/membership.go
new file mode 100644
index 0000000..8307a31
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/schema/membership.go
@@ -0,0 +1,254 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package schema
+
+import (
+	"encoding/json"
+	"fmt"
+
+	"github.com/coreos/go-semver/semver"
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/client/pkg/v3/types"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/membership"
+	"go.etcd.io/etcd/server/v3/etcdserver/version"
+	"go.etcd.io/etcd/server/v3/storage/backend"
+)
+
+const (
+	MemberAttributesSuffix     = "attributes"
+	MemberRaftAttributesSuffix = "raftAttributes"
+)
+
+type membershipBackend struct {
+	lg *zap.Logger
+	be backend.Backend
+}
+
+func NewMembershipBackend(lg *zap.Logger, be backend.Backend) *membershipBackend {
+	return &membershipBackend{
+		lg: lg,
+		be: be,
+	}
+}
+
+func (s *membershipBackend) MustSaveMemberToBackend(m *membership.Member) {
+	mkey := BackendMemberKey(m.ID)
+	mvalue, err := json.Marshal(m)
+	if err != nil {
+		s.lg.Panic("failed to marshal member", zap.Error(err))
+	}
+
+	tx := s.be.BatchTx()
+	tx.LockInsideApply()
+	defer tx.Unlock()
+	tx.UnsafePut(Members, mkey, mvalue)
+}
+
+// MustHackySaveMemberToBackend updates the member in a hacky way.
+// It's only used to fix the issues which are already affected by
+// https://github.com/etcd-io/etcd/issues/19557.
+func (s *membershipBackend) MustHackySaveMemberToBackend(m *membership.Member) {
+	mkey := BackendMemberKey(m.ID)
+	mvalue, err := json.Marshal(m)
+	if err != nil {
+		s.lg.Panic("failed to marshal member", zap.Error(err))
+	}
+
+	tx := s.be.BatchTx()
+	tx.LockOutsideApply()
+	defer tx.Unlock()
+	tx.UnsafePut(Members, mkey, mvalue)
+}
+
+// TrimClusterFromBackend removes all information about cluster (versions)
+// from the v3 backend.
+func (s *membershipBackend) TrimClusterFromBackend() error {
+	tx := s.be.BatchTx()
+	tx.LockOutsideApply()
+	defer tx.Unlock()
+	tx.UnsafeDeleteBucket(Cluster)
+	return nil
+}
+
+func (s *membershipBackend) MustDeleteMemberFromBackend(id types.ID) {
+	mkey := BackendMemberKey(id)
+
+	tx := s.be.BatchTx()
+	tx.LockInsideApply()
+	defer tx.Unlock()
+	tx.UnsafeDelete(Members, mkey)
+	tx.UnsafePut(MembersRemoved, mkey, []byte("removed"))
+}
+
+func (s *membershipBackend) MustReadMembersFromBackend() (map[types.ID]*membership.Member, map[types.ID]bool) {
+	members, removed, err := s.readMembersFromBackend()
+	if err != nil {
+		s.lg.Panic("couldn't read members from backend", zap.Error(err))
+	}
+	return members, removed
+}
+
+func (s *membershipBackend) readMembersFromBackend() (map[types.ID]*membership.Member, map[types.ID]bool, error) {
+	members := make(map[types.ID]*membership.Member)
+	removed := make(map[types.ID]bool)
+
+	tx := s.be.ReadTx()
+	tx.RLock()
+	defer tx.RUnlock()
+	err := tx.UnsafeForEach(Members, func(k, v []byte) error {
+		memberID := mustParseMemberIDFromBytes(s.lg, k)
+		m := &membership.Member{ID: memberID}
+		if err := json.Unmarshal(v, &m); err != nil {
+			return err
+		}
+		members[memberID] = m
+		return nil
+	})
+	if err != nil {
+		return nil, nil, fmt.Errorf("couldn't read members from backend: %w", err)
+	}
+
+	err = tx.UnsafeForEach(MembersRemoved, func(k, v []byte) error {
+		memberID := mustParseMemberIDFromBytes(s.lg, k)
+		removed[memberID] = true
+		return nil
+	})
+	if err != nil {
+		return nil, nil, fmt.Errorf("couldn't read members_removed from backend: %w", err)
+	}
+	return members, removed, nil
+}
+
+// TrimMembershipFromBackend removes all information about members &
+// removed_members from the v3 backend.
+func (s *membershipBackend) TrimMembershipFromBackend() error {
+	s.lg.Info("Trimming membership information from the backend...")
+	tx := s.be.BatchTx()
+	tx.LockOutsideApply()
+	defer tx.Unlock()
+	err := tx.UnsafeForEach(Members, func(k, v []byte) error {
+		tx.UnsafeDelete(Members, k)
+		s.lg.Debug("Removed member from the backend",
+			zap.Stringer("member", mustParseMemberIDFromBytes(s.lg, k)))
+		return nil
+	})
+	if err != nil {
+		return err
+	}
+	return tx.UnsafeForEach(MembersRemoved, func(k, v []byte) error {
+		tx.UnsafeDelete(MembersRemoved, k)
+		s.lg.Debug("Removed removed_member from the backend",
+			zap.Stringer("member", mustParseMemberIDFromBytes(s.lg, k)))
+		return nil
+	})
+}
+
+// MustSaveClusterVersionToBackend saves cluster version to backend.
+// The field is populated since etcd v3.5.
+func (s *membershipBackend) MustSaveClusterVersionToBackend(ver *semver.Version) {
+	ckey := ClusterClusterVersionKeyName
+
+	tx := s.be.BatchTx()
+	tx.LockInsideApply()
+	defer tx.Unlock()
+	tx.UnsafePut(Cluster, ckey, []byte(ver.String()))
+}
+
+// MustSaveDowngradeToBackend saves downgrade info to backend.
+// The field is populated since etcd v3.5.
+func (s *membershipBackend) MustSaveDowngradeToBackend(downgrade *version.DowngradeInfo) {
+	dkey := ClusterDowngradeKeyName
+	dvalue, err := json.Marshal(downgrade)
+	if err != nil {
+		s.lg.Panic("failed to marshal downgrade information", zap.Error(err))
+	}
+	tx := s.be.BatchTx()
+	tx.LockInsideApply()
+	defer tx.Unlock()
+	tx.UnsafePut(Cluster, dkey, dvalue)
+}
+
+func (s *membershipBackend) MustCreateBackendBuckets() {
+	tx := s.be.BatchTx()
+	tx.LockOutsideApply()
+	defer tx.Unlock()
+	tx.UnsafeCreateBucket(Members)
+	tx.UnsafeCreateBucket(MembersRemoved)
+	tx.UnsafeCreateBucket(Cluster)
+}
+
+func mustParseMemberIDFromBytes(lg *zap.Logger, key []byte) types.ID {
+	id, err := types.IDFromString(string(key))
+	if err != nil {
+		lg.Panic("failed to parse member id from key", zap.Error(err))
+	}
+	return id
+}
+
+// ClusterVersionFromBackend reads cluster version from backend.
+// The field is populated since etcd v3.5.
+func (s *membershipBackend) ClusterVersionFromBackend() *semver.Version {
+	ckey := ClusterClusterVersionKeyName
+	tx := s.be.ReadTx()
+	tx.RLock()
+	defer tx.RUnlock()
+	keys, vals := tx.UnsafeRange(Cluster, ckey, nil, 0)
+	if len(keys) == 0 {
+		return nil
+	}
+	if len(keys) != 1 {
+		s.lg.Panic(
+			"unexpected number of keys when getting cluster version from backend",
+			zap.Int("number-of-key", len(keys)),
+		)
+	}
+	return semver.Must(semver.NewVersion(string(vals[0])))
+}
+
+// DowngradeInfoFromBackend reads downgrade info from backend.
+// The field is populated since etcd v3.5.
+func (s *membershipBackend) DowngradeInfoFromBackend() *version.DowngradeInfo {
+	dkey := ClusterDowngradeKeyName
+	tx := s.be.ReadTx()
+	tx.RLock()
+	defer tx.RUnlock()
+	keys, vals := tx.UnsafeRange(Cluster, dkey, nil, 0)
+	if len(keys) == 0 {
+		return nil
+	}
+
+	if len(keys) != 1 {
+		s.lg.Panic(
+			"unexpected number of keys when getting cluster version from backend",
+			zap.Int("number-of-key", len(keys)),
+		)
+	}
+	var d version.DowngradeInfo
+	if err := json.Unmarshal(vals[0], &d); err != nil {
+		s.lg.Panic("failed to unmarshal downgrade information", zap.Error(err))
+	}
+
+	// verify the downgrade info from backend
+	if d.Enabled {
+		if _, err := semver.NewVersion(d.TargetVersion); err != nil {
+			s.lg.Panic(
+				"unexpected version format of the downgrade target version from backend",
+				zap.String("target-version", d.TargetVersion),
+			)
+		}
+	}
+	return &d
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/schema/migration.go b/vendor/go.etcd.io/etcd/server/v3/storage/schema/migration.go
new file mode 100644
index 0000000..a34fa2f
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/schema/migration.go
@@ -0,0 +1,108 @@
+// Copyright 2021 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package schema
+
+import (
+	"fmt"
+
+	"github.com/coreos/go-semver/semver"
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/api/v3/version"
+	"go.etcd.io/etcd/server/v3/storage/backend"
+)
+
+type migrationPlan []migrationStep
+
+func newPlan(lg *zap.Logger, current semver.Version, target semver.Version) (plan migrationPlan, err error) {
+	current = trimToMinor(current)
+	target = trimToMinor(target)
+	if current.Major != target.Major {
+		lg.Error("Changing major storage version is not supported",
+			zap.String("storage-version", current.String()),
+			zap.String("target-storage-version", target.String()),
+		)
+		return plan, fmt.Errorf("changing major storage version is not supported")
+	}
+	for !current.Equal(target) {
+		isUpgrade := current.Minor < target.Minor
+
+		changes, err := schemaChangesForVersion(current, isUpgrade)
+		if err != nil {
+			return plan, err
+		}
+		step := newMigrationStep(current, isUpgrade, changes)
+		plan = append(plan, step)
+		current = step.target
+	}
+	return plan, nil
+}
+
+func (p migrationPlan) Execute(lg *zap.Logger, tx backend.BatchTx) error {
+	tx.LockOutsideApply()
+	defer tx.Unlock()
+	return p.unsafeExecute(lg, tx)
+}
+
+func (p migrationPlan) unsafeExecute(lg *zap.Logger, tx backend.UnsafeReadWriter) (err error) {
+	for _, s := range p {
+		err = s.unsafeExecute(lg, tx)
+		if err != nil {
+			return err
+		}
+		lg.Info("updated storage version", zap.String("new-storage-version", s.target.String()))
+	}
+	return nil
+}
+
+// migrationStep represents a single migrationStep of migrating etcd storage between two minor versions.
+type migrationStep struct {
+	target  semver.Version
+	actions ActionList
+}
+
+func newMigrationStep(v semver.Version, isUpgrade bool, changes []schemaChange) (step migrationStep) {
+	step.actions = make(ActionList, len(changes))
+	for i, change := range changes {
+		if isUpgrade {
+			step.actions[i] = change.upgradeAction()
+		} else {
+			step.actions[len(changes)-1-i] = change.downgradeAction()
+		}
+	}
+	if isUpgrade {
+		step.target = semver.Version{Major: v.Major, Minor: v.Minor + 1}
+	} else {
+		step.target = semver.Version{Major: v.Major, Minor: v.Minor - 1}
+	}
+	return step
+}
+
+// unsafeExecute is non thread-safe version of execute.
+func (s migrationStep) unsafeExecute(lg *zap.Logger, tx backend.UnsafeReadWriter) error {
+	err := s.actions.unsafeExecute(lg, tx)
+	if err != nil {
+		return err
+	}
+	// Storage version is available since v3.6, downgrading target v3.5 should clean this field.
+	if !s.target.LessThan(version.V3_6) {
+		UnsafeSetStorageVersion(tx, &s.target)
+	}
+	return nil
+}
+
+func trimToMinor(ver semver.Version) semver.Version {
+	return semver.Version{Major: ver.Major, Minor: ver.Minor}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/schema/schema.go b/vendor/go.etcd.io/etcd/server/v3/storage/schema/schema.go
new file mode 100644
index 0000000..2150c9e
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/schema/schema.go
@@ -0,0 +1,138 @@
+// Copyright 2021 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package schema
+
+import (
+	"fmt"
+
+	"github.com/coreos/go-semver/semver"
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/api/v3/version"
+	"go.etcd.io/etcd/server/v3/storage/backend"
+	"go.etcd.io/etcd/server/v3/storage/wal"
+)
+
+// Validate checks provided backend to confirm that schema used is supported.
+func Validate(lg *zap.Logger, tx backend.ReadTx) error {
+	tx.RLock()
+	defer tx.RUnlock()
+	return unsafeValidate(lg, tx)
+}
+
+func unsafeValidate(lg *zap.Logger, tx backend.UnsafeReader) error {
+	current, err := UnsafeDetectSchemaVersion(lg, tx)
+	if err != nil {
+		// v3.5 requires a wal snapshot to persist its fields, so we can assign it a schema version.
+		lg.Warn("Failed to detect storage schema version. Please wait till wal snapshot before upgrading cluster.")
+		return nil
+	}
+	_, err = newPlan(lg, current, localBinaryVersion())
+	return err
+}
+
+func localBinaryVersion() semver.Version {
+	v := semver.New(version.Version)
+	return semver.Version{Major: v.Major, Minor: v.Minor}
+}
+
+// Migrate updates storage schema to provided target version.
+// Downgrading requires that provided WAL doesn't contain unsupported entries.
+func Migrate(lg *zap.Logger, tx backend.BatchTx, w wal.Version, target semver.Version) error {
+	tx.LockOutsideApply()
+	defer tx.Unlock()
+	return UnsafeMigrate(lg, tx, w, target)
+}
+
+// UnsafeMigrate is non thread-safe version of Migrate.
+func UnsafeMigrate(lg *zap.Logger, tx backend.UnsafeReadWriter, w wal.Version, target semver.Version) error {
+	current, err := UnsafeDetectSchemaVersion(lg, tx)
+	if err != nil {
+		return fmt.Errorf("cannot detect storage schema version: %w", err)
+	}
+	plan, err := newPlan(lg, current, target)
+	if err != nil {
+		return fmt.Errorf("cannot create migration plan: %w", err)
+	}
+	if target.LessThan(current) {
+		minVersion := w.MinimalEtcdVersion()
+		if minVersion != nil && target.LessThan(*minVersion) {
+			// Occasionally we may see this error during downgrade test due to ClusterVersionSet,
+			// which is harmless. Please read https://github.com/etcd-io/etcd/pull/13405#discussion_r1890378185.
+			return fmt.Errorf("cannot downgrade storage, WAL contains newer entries, as the target version (%s) is lower than the version (%s) detected from WAL logs",
+				target.String(), minVersion.String())
+		}
+	}
+	return plan.unsafeExecute(lg, tx)
+}
+
+// DetectSchemaVersion returns version of storage schema. Returned value depends on etcd version that created the backend. For
+// * v3.6 and newer will return storage version.
+// * v3.5 will return it's version if it includes all storage fields added in v3.5 (might require a snapshot).
+// * v3.4 and older is not supported and will return error.
+func DetectSchemaVersion(lg *zap.Logger, tx backend.ReadTx) (v semver.Version, err error) {
+	tx.RLock()
+	defer tx.RUnlock()
+	return UnsafeDetectSchemaVersion(lg, tx)
+}
+
+// UnsafeDetectSchemaVersion non-threadsafe version of DetectSchemaVersion.
+func UnsafeDetectSchemaVersion(lg *zap.Logger, tx backend.UnsafeReader) (v semver.Version, err error) {
+	vp := UnsafeReadStorageVersion(tx)
+	if vp != nil {
+		return *vp, nil
+	}
+
+	// TODO: remove the operations of reading the field `term`
+	// in 3.7. We only need to be back-compatible with 3.6 when
+	// we are running 3.7, and the `storageVersion` already exists
+	// in all versions >= 3.6, so we don't need to use any other
+	// fields to identify the etcd's storage version.
+	_, term := UnsafeReadConsistentIndex(tx)
+	if term == 0 {
+		return v, fmt.Errorf("missing term information")
+	}
+	return version.V3_5, nil
+}
+
+func schemaChangesForVersion(v semver.Version, isUpgrade bool) ([]schemaChange, error) {
+	// changes should be taken from higher version
+	higherV := v
+	if isUpgrade {
+		higherV = semver.Version{Major: v.Major, Minor: v.Minor + 1}
+	}
+
+	actions, found := schemaChanges[higherV]
+	if !found {
+		if isUpgrade {
+			return nil, fmt.Errorf("version %q is not supported", higherV.String())
+		}
+		return nil, fmt.Errorf("version %q is not supported", v.String())
+	}
+	return actions, nil
+}
+
+var (
+	// schemaChanges list changes that were introduced in a particular version.
+	// schema was introduced in v3.6 as so its changes were not tracked before.
+	schemaChanges = map[semver.Version][]schemaChange{
+		version.V3_6: {
+			addNewField(Meta, MetaStorageVersionName, emptyStorageVersion),
+		},
+	}
+	// emptyStorageVersion is used for v3.6 Step for the first time, in all other version StoragetVersion should be set by migrator.
+	// Adding a addNewField for StorageVersion we can reuse logic to remove it when downgrading to v3.5
+	emptyStorageVersion = []byte("")
+)
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/schema/version.go b/vendor/go.etcd.io/etcd/server/v3/storage/schema/version.go
new file mode 100644
index 0000000..83984e6
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/schema/version.go
@@ -0,0 +1,67 @@
+// Copyright 2021 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package schema
+
+import (
+	"github.com/coreos/go-semver/semver"
+
+	"go.etcd.io/bbolt"
+	"go.etcd.io/etcd/server/v3/storage/backend"
+)
+
+// ReadStorageVersion loads storage version from given backend transaction.
+// Populated since v3.6
+func ReadStorageVersion(tx backend.ReadTx) *semver.Version {
+	tx.RLock()
+	defer tx.RUnlock()
+	return UnsafeReadStorageVersion(tx)
+}
+
+// UnsafeReadStorageVersion loads storage version from given backend transaction.
+// Populated since v3.6
+func UnsafeReadStorageVersion(tx backend.UnsafeReader) *semver.Version {
+	_, vs := tx.UnsafeRange(Meta, MetaStorageVersionName, nil, 1)
+	if len(vs) == 0 {
+		return nil
+	}
+	v, err := semver.NewVersion(string(vs[0]))
+	if err != nil {
+		return nil
+	}
+	return v
+}
+
+// ReadStorageVersionFromSnapshot loads storage version from given bbolt transaction.
+// Populated since v3.6
+func ReadStorageVersionFromSnapshot(tx *bbolt.Tx) *semver.Version {
+	v := tx.Bucket(Meta.Name()).Get(MetaStorageVersionName)
+	version, err := semver.NewVersion(string(v))
+	if err != nil {
+		return nil
+	}
+	return version
+}
+
+// UnsafeSetStorageVersion updates etcd storage version in backend.
+// Populated since v3.6
+func UnsafeSetStorageVersion(tx backend.UnsafeWriter, v *semver.Version) {
+	sv := semver.Version{Major: v.Major, Minor: v.Minor}
+	tx.UnsafePut(Meta, MetaStorageVersionName, []byte(sv.String()))
+}
+
+// UnsafeClearStorageVersion removes etcd storage version in backend.
+func UnsafeClearStorageVersion(tx backend.UnsafeWriter) {
+	tx.UnsafeDelete(Meta, MetaStorageVersionName)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/storage.go b/vendor/go.etcd.io/etcd/server/v3/storage/storage.go
new file mode 100644
index 0000000..99a37a2
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/storage.go
@@ -0,0 +1,135 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package storage
+
+import (
+	"errors"
+	"sync"
+
+	"github.com/coreos/go-semver/semver"
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/server/v3/etcdserver/api/snap"
+	"go.etcd.io/etcd/server/v3/storage/wal"
+	"go.etcd.io/etcd/server/v3/storage/wal/walpb"
+	"go.etcd.io/raft/v3/raftpb"
+)
+
+type Storage interface {
+	// Save function saves ents and state to the underlying stable storage.
+	// Save MUST block until st and ents are on stable storage.
+	Save(st raftpb.HardState, ents []raftpb.Entry) error
+	// SaveSnap function saves snapshot to the underlying stable storage.
+	SaveSnap(snap raftpb.Snapshot) error
+	// Close closes the Storage and performs finalization.
+	Close() error
+	// Release releases the locked wal files older than the provided snapshot.
+	Release(snap raftpb.Snapshot) error
+	// Sync WAL
+	Sync() error
+	// MinimalEtcdVersion returns minimal etcd storage able to interpret WAL log.
+	MinimalEtcdVersion() *semver.Version
+}
+
+type storage struct {
+	lg *zap.Logger
+	s  *snap.Snapshotter
+
+	// Mutex protected variables
+	mux sync.RWMutex
+	w   *wal.WAL
+}
+
+func NewStorage(lg *zap.Logger, w *wal.WAL, s *snap.Snapshotter) Storage {
+	return &storage{lg: lg, w: w, s: s}
+}
+
+// SaveSnap saves the snapshot file to disk and writes the WAL snapshot entry.
+func (st *storage) SaveSnap(snap raftpb.Snapshot) error {
+	st.mux.RLock()
+	defer st.mux.RUnlock()
+	walsnap := walpb.Snapshot{
+		Index:     snap.Metadata.Index,
+		Term:      snap.Metadata.Term,
+		ConfState: &snap.Metadata.ConfState,
+	}
+	// save the snapshot file before writing the snapshot to the wal.
+	// This makes it possible for the snapshot file to become orphaned, but prevents
+	// a WAL snapshot entry from having no corresponding snapshot file.
+	err := st.s.SaveSnap(snap)
+	if err != nil {
+		return err
+	}
+	// gofail: var raftBeforeWALSaveSnaphot struct{}
+
+	return st.w.SaveSnapshot(walsnap)
+}
+
+// Release releases resources older than the given snap and are no longer needed:
+// - releases the locks to the wal files that are older than the provided wal for the given snap.
+// - deletes any .snap.db files that are older than the given snap.
+func (st *storage) Release(snap raftpb.Snapshot) error {
+	st.mux.RLock()
+	defer st.mux.RUnlock()
+	if err := st.w.ReleaseLockTo(snap.Metadata.Index); err != nil {
+		return err
+	}
+	return st.s.ReleaseSnapDBs(snap)
+}
+
+func (st *storage) Save(s raftpb.HardState, ents []raftpb.Entry) error {
+	st.mux.RLock()
+	defer st.mux.RUnlock()
+	return st.w.Save(s, ents)
+}
+
+func (st *storage) Close() error {
+	st.mux.Lock()
+	defer st.mux.Unlock()
+	return st.w.Close()
+}
+
+func (st *storage) Sync() error {
+	st.mux.RLock()
+	defer st.mux.RUnlock()
+	return st.w.Sync()
+}
+
+func (st *storage) MinimalEtcdVersion() *semver.Version {
+	st.mux.Lock()
+	defer st.mux.Unlock()
+	walsnap := walpb.Snapshot{}
+
+	sn, err := st.s.Load()
+	if err != nil && !errors.Is(err, snap.ErrNoSnapshot) {
+		panic(err)
+	}
+	if sn != nil {
+		walsnap.Index = sn.Metadata.Index
+		walsnap.Term = sn.Metadata.Term
+		walsnap.ConfState = &sn.Metadata.ConfState
+	}
+	w, err := st.w.Reopen(st.lg, walsnap)
+	if err != nil {
+		panic(err)
+	}
+	_, _, ents, err := w.ReadAll()
+	if err != nil {
+		panic(err)
+	}
+	v := wal.MinimalEtcdVersion(ents)
+	st.w = w
+	return v
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/util.go b/vendor/go.etcd.io/etcd/server/v3/storage/util.go
new file mode 100644
index 0000000..0dc7f1c
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/util.go
@@ -0,0 +1,160 @@
+// Copyright 2021 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package storage
+
+import (
+	"encoding/json"
+	"fmt"
+	"sort"
+
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/client/pkg/v3/types"
+	"go.etcd.io/etcd/pkg/v3/pbutil"
+	"go.etcd.io/etcd/server/v3/config"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/membership"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v2store"
+	"go.etcd.io/raft/v3/raftpb"
+)
+
+// AssertNoV2StoreContent -> depending on the deprecation stage, warns or report an error
+// if the v2store contains custom content.
+func AssertNoV2StoreContent(lg *zap.Logger, st v2store.Store, deprecationStage config.V2DeprecationEnum) error {
+	metaOnly, err := membership.IsMetaStoreOnly(st)
+	if err != nil {
+		return err
+	}
+	if metaOnly {
+		return nil
+	}
+	if deprecationStage.IsAtLeast(config.V2Depr1WriteOnly) {
+		return fmt.Errorf("detected disallowed custom content in v2store for stage --v2-deprecation=%s", deprecationStage)
+	}
+	lg.Warn("detected custom v2store content. Etcd v3.5 is the last version allowing to access it using API v2. Please remove the content.")
+	return nil
+}
+
+// CreateConfigChangeEnts creates a series of Raft entries (i.e.
+// EntryConfChange) to remove the set of given IDs from the cluster. The ID
+// `self` is _not_ removed, even if present in the set.
+// If `self` is not inside the given ids, it creates a Raft entry to add a
+// default member with the given `self`.
+func CreateConfigChangeEnts(lg *zap.Logger, ids []uint64, self uint64, term, index uint64) []raftpb.Entry {
+	found := false
+	for _, id := range ids {
+		if id == self {
+			found = true
+		}
+	}
+
+	var ents []raftpb.Entry
+	next := index + 1
+
+	// NB: always add self first, then remove other nodes. Raft will panic if the
+	// set of voters ever becomes empty.
+	if !found {
+		m := membership.Member{
+			ID:             types.ID(self),
+			RaftAttributes: membership.RaftAttributes{PeerURLs: []string{"http://localhost:2380"}},
+		}
+		ctx, err := json.Marshal(m)
+		if err != nil {
+			lg.Panic("failed to marshal member", zap.Error(err))
+		}
+		cc := &raftpb.ConfChange{
+			Type:    raftpb.ConfChangeAddNode,
+			NodeID:  self,
+			Context: ctx,
+		}
+		e := raftpb.Entry{
+			Type:  raftpb.EntryConfChange,
+			Data:  pbutil.MustMarshal(cc),
+			Term:  term,
+			Index: next,
+		}
+		ents = append(ents, e)
+		next++
+	}
+
+	for _, id := range ids {
+		if id == self {
+			continue
+		}
+		cc := &raftpb.ConfChange{
+			Type:   raftpb.ConfChangeRemoveNode,
+			NodeID: id,
+		}
+		e := raftpb.Entry{
+			Type:  raftpb.EntryConfChange,
+			Data:  pbutil.MustMarshal(cc),
+			Term:  term,
+			Index: next,
+		}
+		ents = append(ents, e)
+		next++
+	}
+
+	return ents
+}
+
+// GetEffectiveNodeIdsFromWalEntries returns an ordered set of IDs included in the given snapshot and
+// the entries.
+//
+// Deprecated: use GetEffectiveNodeIDsFromWALEntries instead.
+//
+//revive:disable-next-line:var-naming
+func GetEffectiveNodeIdsFromWalEntries(lg *zap.Logger, snap *raftpb.Snapshot, ents []raftpb.Entry) []uint64 {
+	return GetEffectiveNodeIDsFromWALEntries(lg, snap, ents)
+}
+
+// GetEffectiveNodeIDsFromWALEntries returns an ordered set of IDs included in the given snapshot and
+// the entries. The given snapshot/entries can contain three kinds of
+// ID-related entry:
+// - ConfChangeAddNode, in which case the contained ID will Be added into the set.
+// - ConfChangeRemoveNode, in which case the contained ID will Be removed from the set.
+// - ConfChangeAddLearnerNode, in which the contained ID will Be added into the set.
+func GetEffectiveNodeIDsFromWALEntries(lg *zap.Logger, snap *raftpb.Snapshot, ents []raftpb.Entry) []uint64 {
+	ids := make(map[uint64]bool)
+	if snap != nil {
+		for _, id := range snap.Metadata.ConfState.Voters {
+			ids[id] = true
+		}
+	}
+	for _, e := range ents {
+		if e.Type != raftpb.EntryConfChange {
+			continue
+		}
+		var cc raftpb.ConfChange
+		pbutil.MustUnmarshal(&cc, e.Data)
+		switch cc.Type {
+		case raftpb.ConfChangeAddLearnerNode:
+			ids[cc.NodeID] = true
+		case raftpb.ConfChangeAddNode:
+			ids[cc.NodeID] = true
+		case raftpb.ConfChangeRemoveNode:
+			delete(ids, cc.NodeID)
+		case raftpb.ConfChangeUpdateNode:
+			// do nothing
+		default:
+			lg.Panic("unknown ConfChange Type", zap.String("type", cc.Type.String()))
+		}
+	}
+	sids := make(types.Uint64Slice, 0, len(ids))
+	for id := range ids {
+		sids = append(sids, id)
+	}
+	sort.Sort(sids)
+	return sids
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/wal/decoder.go b/vendor/go.etcd.io/etcd/server/v3/storage/wal/decoder.go
new file mode 100644
index 0000000..bdd4962
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/wal/decoder.go
@@ -0,0 +1,229 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package wal
+
+import (
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"hash"
+	"io"
+	"sync"
+
+	"go.etcd.io/etcd/client/pkg/v3/fileutil"
+	"go.etcd.io/etcd/pkg/v3/crc"
+	"go.etcd.io/etcd/pkg/v3/pbutil"
+	"go.etcd.io/etcd/server/v3/storage/wal/walpb"
+	"go.etcd.io/raft/v3/raftpb"
+)
+
+const minSectorSize = 512
+
+// frameSizeBytes is frame size in bytes, including record size and padding size.
+const frameSizeBytes = 8
+
+type Decoder interface {
+	Decode(rec *walpb.Record) error
+	LastOffset() int64
+	LastCRC() uint32
+	UpdateCRC(prevCrc uint32)
+}
+
+type decoder struct {
+	mu  sync.Mutex
+	brs []*fileutil.FileBufReader
+
+	// lastValidOff file offset following the last valid decoded record
+	lastValidOff int64
+	crc          hash.Hash32
+
+	// continueOnCrcError - causes the decoder to continue working even in case of crc mismatch.
+	// This is a desired mode for tools performing inspection of the corrupted WAL logs.
+	// See comments on 'Decode' method for semantic.
+	continueOnCrcError bool
+}
+
+func NewDecoderAdvanced(continueOnCrcError bool, r ...fileutil.FileReader) Decoder {
+	readers := make([]*fileutil.FileBufReader, len(r))
+	for i := range r {
+		readers[i] = fileutil.NewFileBufReader(r[i])
+	}
+	return &decoder{
+		brs:                readers,
+		crc:                crc.New(0, crcTable),
+		continueOnCrcError: continueOnCrcError,
+	}
+}
+
+func NewDecoder(r ...fileutil.FileReader) Decoder {
+	return NewDecoderAdvanced(false, r...)
+}
+
+// Decode reads the next record out of the file.
+// In the success path, fills 'rec' and returns nil.
+// When it fails, it returns err and usually resets 'rec' to the defaults.
+// When continueOnCrcError is set, the method may return ErrUnexpectedEOF or ErrCRCMismatch, but preserve the read
+// (potentially corrupted) record content.
+func (d *decoder) Decode(rec *walpb.Record) error {
+	rec.Reset()
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	return d.decodeRecord(rec)
+}
+
+func (d *decoder) decodeRecord(rec *walpb.Record) error {
+	if len(d.brs) == 0 {
+		return io.EOF
+	}
+
+	fileBufReader := d.brs[0]
+	l, err := readInt64(fileBufReader)
+	if errors.Is(err, io.EOF) || (err == nil && l == 0) {
+		// hit end of file or preallocated space
+		d.brs = d.brs[1:]
+		if len(d.brs) == 0 {
+			return io.EOF
+		}
+		d.lastValidOff = 0
+		return d.decodeRecord(rec)
+	}
+	if err != nil {
+		return err
+	}
+
+	recBytes, padBytes := decodeFrameSize(l)
+	// The length of current WAL entry must be less than the remaining file size.
+	maxEntryLimit := fileBufReader.FileInfo().Size() - d.lastValidOff - padBytes
+	if recBytes > maxEntryLimit {
+		return fmt.Errorf("%w: [wal] max entry size limit exceeded when reading %q, recBytes: %d, fileSize(%d) - offset(%d) - padBytes(%d) = entryLimit(%d)",
+			io.ErrUnexpectedEOF, fileBufReader.FileInfo().Name(), recBytes, fileBufReader.FileInfo().Size(), d.lastValidOff, padBytes, maxEntryLimit)
+	}
+
+	data := make([]byte, recBytes+padBytes)
+	if _, err = io.ReadFull(fileBufReader, data); err != nil {
+		// ReadFull returns io.EOF only if no bytes were read
+		// the decoder should treat this as an ErrUnexpectedEOF instead.
+		if errors.Is(err, io.EOF) {
+			err = io.ErrUnexpectedEOF
+		}
+		return err
+	}
+	if err := rec.Unmarshal(data[:recBytes]); err != nil {
+		if d.isTornEntry(data) {
+			return io.ErrUnexpectedEOF
+		}
+		return err
+	}
+
+	// skip crc checking if the record type is CrcType
+	if rec.Type != CrcType {
+		_, err := d.crc.Write(rec.Data)
+		if err != nil {
+			return err
+		}
+		if err := rec.Validate(d.crc.Sum32()); err != nil {
+			if !d.continueOnCrcError {
+				rec.Reset()
+			} else {
+				// If we continue, we want to update lastValidOff, such that following errors are consistent
+				defer func() { d.lastValidOff += frameSizeBytes + recBytes + padBytes }()
+			}
+
+			if d.isTornEntry(data) {
+				return fmt.Errorf("%w: in file '%s' at position: %d", io.ErrUnexpectedEOF, fileBufReader.FileInfo().Name(), d.lastValidOff)
+			}
+			return fmt.Errorf("%w: in file '%s' at position: %d", err, fileBufReader.FileInfo().Name(), d.lastValidOff)
+		}
+	}
+	// record decoded as valid; point last valid offset to end of record
+	d.lastValidOff += frameSizeBytes + recBytes + padBytes
+	return nil
+}
+
+func decodeFrameSize(lenField int64) (recBytes int64, padBytes int64) {
+	// the record size is stored in the lower 56 bits of the 64-bit length
+	recBytes = int64(uint64(lenField) & ^(uint64(0xff) << 56))
+	// non-zero padding is indicated by set MSb / a negative length
+	if lenField < 0 {
+		// padding is stored in lower 3 bits of length MSB
+		padBytes = int64((uint64(lenField) >> 56) & 0x7)
+	}
+	return recBytes, padBytes
+}
+
+// isTornEntry determines whether the last entry of the WAL was partially written
+// and corrupted because of a torn write.
+func (d *decoder) isTornEntry(data []byte) bool {
+	if len(d.brs) != 1 {
+		return false
+	}
+
+	fileOff := d.lastValidOff + frameSizeBytes
+	curOff := 0
+	var chunks [][]byte
+	// split data on sector boundaries
+	for curOff < len(data) {
+		chunkLen := int(minSectorSize - (fileOff % minSectorSize))
+		if chunkLen > len(data)-curOff {
+			chunkLen = len(data) - curOff
+		}
+		chunks = append(chunks, data[curOff:curOff+chunkLen])
+		fileOff += int64(chunkLen)
+		curOff += chunkLen
+	}
+
+	// if any data for a sector chunk is all 0, it's a torn write
+	for _, sect := range chunks {
+		isZero := true
+		for _, v := range sect {
+			if v != 0 {
+				isZero = false
+				break
+			}
+		}
+		if isZero {
+			return true
+		}
+	}
+	return false
+}
+
+func (d *decoder) UpdateCRC(prevCrc uint32) {
+	d.crc = crc.New(prevCrc, crcTable)
+}
+
+func (d *decoder) LastCRC() uint32 {
+	return d.crc.Sum32()
+}
+
+func (d *decoder) LastOffset() int64 { return d.lastValidOff }
+
+func MustUnmarshalEntry(d []byte) raftpb.Entry {
+	var e raftpb.Entry
+	pbutil.MustUnmarshal(&e, d)
+	return e
+}
+
+func MustUnmarshalState(d []byte) raftpb.HardState {
+	var s raftpb.HardState
+	pbutil.MustUnmarshal(&s, d)
+	return s
+}
+
+func readInt64(r io.Reader) (int64, error) {
+	var n int64
+	err := binary.Read(r, binary.LittleEndian, &n)
+	return n, err
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/wal/doc.go b/vendor/go.etcd.io/etcd/server/v3/storage/wal/doc.go
new file mode 100644
index 0000000..0f7ef85
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/wal/doc.go
@@ -0,0 +1,74 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/*
+Package wal provides an implementation of write ahead log that is used by
+etcd.
+
+A WAL is created at a particular directory and is made up of a number of
+segmented WAL files. Inside each file the raft state and entries are appended
+to it with the Save method:
+
+	metadata := []byte{}
+	w, err := wal.Create(zap.NewExample(), "/var/lib/etcd", metadata)
+	...
+	err := w.Save(s, ents)
+
+After saving a raft snapshot to disk, SaveSnapshot method should be called to
+record it. So WAL can match with the saved snapshot when restarting.
+
+	err := w.SaveSnapshot(walpb.Snapshot{Index: 10, Term: 2})
+
+When a user has finished using a WAL it must be closed:
+
+	w.Close()
+
+Each WAL file is a stream of WAL records. A WAL record is a length field and a wal record
+protobuf. The record protobuf contains a CRC, a type, and a data payload. The length field is a
+64-bit packed structure holding the length of the remaining logical record data in its lower
+56 bits and its physical padding in the first three bits of the most significant byte. Each
+record is 8-byte aligned so that the length field is never torn. The CRC contains the CRC32
+value of all record protobufs preceding the current record.
+
+WAL files are placed inside the directory in the following format:
+$seq-$index.wal
+
+The first WAL file to be created will be 0000000000000000-0000000000000000.wal
+indicating an initial sequence of 0 and an initial raft index of 0. The first
+entry written to WAL MUST have raft index 0.
+
+WAL will cut its current tail wal file if its size exceeds 64 MB. This will increment an internal
+sequence number and cause a new file to be created. If the last raft index saved
+was 0x20 and this is the first time cut has been called on this WAL then the sequence will
+increment from 0x0 to 0x1. The new file will be: 0000000000000001-0000000000000021.wal.
+If a second cut issues 0x10 entries with incremental index later, then the file will be called:
+0000000000000002-0000000000000031.wal.
+
+At a later time a WAL can be opened at a particular snapshot. If there is no
+snapshot, an empty snapshot should be passed in.
+
+	w, err := wal.Open("/var/lib/etcd", walpb.Snapshot{Index: 10, Term: 2})
+	...
+
+The snapshot must have been written to the WAL.
+
+Additional items cannot be Saved to this WAL until all the items from the given
+snapshot to the end of the WAL are read first:
+
+	metadata, state, ents, err := w.ReadAll()
+
+This will give you the metadata, the last raft.State and the slice of
+raft.Entry items in the log.
+*/
+package wal
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/wal/encoder.go b/vendor/go.etcd.io/etcd/server/v3/storage/wal/encoder.go
new file mode 100644
index 0000000..5944ba7
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/wal/encoder.go
@@ -0,0 +1,133 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package wal
+
+import (
+	"encoding/binary"
+	"hash"
+	"io"
+	"os"
+	"sync"
+	"time"
+
+	"go.etcd.io/etcd/pkg/v3/crc"
+	"go.etcd.io/etcd/pkg/v3/ioutil"
+	"go.etcd.io/etcd/server/v3/storage/wal/walpb"
+)
+
+// walPageBytes is the alignment for flushing records to the backing Writer.
+// It should be a multiple of the minimum sector size so that WAL can safely
+// distinguish between torn writes and ordinary data corruption.
+const walPageBytes = 8 * minSectorSize
+
+type encoder struct {
+	mu sync.Mutex
+	bw *ioutil.PageWriter
+
+	crc       hash.Hash32
+	buf       []byte
+	uint64buf []byte
+}
+
+func newEncoder(w io.Writer, prevCrc uint32, pageOffset int) *encoder {
+	return &encoder{
+		bw:  ioutil.NewPageWriter(w, walPageBytes, pageOffset),
+		crc: crc.New(prevCrc, crcTable),
+		// 1MB buffer
+		buf:       make([]byte, 1024*1024),
+		uint64buf: make([]byte, 8),
+	}
+}
+
+// newFileEncoder creates a new encoder with current file offset for the page writer.
+func newFileEncoder(f *os.File, prevCrc uint32) (*encoder, error) {
+	offset, err := f.Seek(0, io.SeekCurrent)
+	if err != nil {
+		return nil, err
+	}
+	return newEncoder(f, prevCrc, int(offset)), nil
+}
+
+func (e *encoder) encode(rec *walpb.Record) error {
+	e.mu.Lock()
+	defer e.mu.Unlock()
+
+	e.crc.Write(rec.Data)
+	rec.Crc = e.crc.Sum32()
+	var (
+		data []byte
+		err  error
+		n    int
+	)
+
+	if rec.Size() > len(e.buf) {
+		data, err = rec.Marshal()
+		if err != nil {
+			return err
+		}
+	} else {
+		n, err = rec.MarshalTo(e.buf)
+		if err != nil {
+			return err
+		}
+		data = e.buf[:n]
+	}
+
+	data, lenField := prepareDataWithPadding(data)
+
+	return write(e.bw, e.uint64buf, data, lenField)
+}
+
+func encodeFrameSize(dataBytes int) (lenField uint64, padBytes int) {
+	lenField = uint64(dataBytes)
+	// force 8 byte alignment so length never gets a torn write
+	padBytes = (8 - (dataBytes % 8)) % 8
+	if padBytes != 0 {
+		lenField |= uint64(0x80|padBytes) << 56
+	}
+	return lenField, padBytes
+}
+
+func (e *encoder) flush() error {
+	e.mu.Lock()
+	defer e.mu.Unlock()
+	return e.bw.Flush()
+}
+
+func prepareDataWithPadding(data []byte) ([]byte, uint64) {
+	lenField, padBytes := encodeFrameSize(len(data))
+	if padBytes != 0 {
+		data = append(data, make([]byte, padBytes)...)
+	}
+	return data, lenField
+}
+
+func write(w io.Writer, uint64buf, data []byte, lenField uint64) error {
+	// write padding info
+	binary.LittleEndian.PutUint64(uint64buf, lenField)
+
+	start := time.Now()
+	nv, err := w.Write(uint64buf)
+	walWriteBytes.Add(float64(nv))
+	if err != nil {
+		return err
+	}
+
+	// write the record with padding
+	n, err := w.Write(data)
+	walWriteSec.Observe(time.Since(start).Seconds())
+	walWriteBytes.Add(float64(n))
+	return err
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/wal/file_pipeline.go b/vendor/go.etcd.io/etcd/server/v3/storage/wal/file_pipeline.go
new file mode 100644
index 0000000..c8ee4cc
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/wal/file_pipeline.go
@@ -0,0 +1,106 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package wal
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/client/pkg/v3/fileutil"
+)
+
+// filePipeline pipelines allocating disk space
+type filePipeline struct {
+	lg *zap.Logger
+
+	// dir to put files
+	dir string
+	// size of files to make, in bytes
+	size int64
+	// count number of files generated
+	count int
+
+	filec chan *fileutil.LockedFile
+	errc  chan error
+	donec chan struct{}
+}
+
+func newFilePipeline(lg *zap.Logger, dir string, fileSize int64) *filePipeline {
+	if lg == nil {
+		lg = zap.NewNop()
+	}
+	fp := &filePipeline{
+		lg:    lg,
+		dir:   dir,
+		size:  fileSize,
+		filec: make(chan *fileutil.LockedFile),
+		errc:  make(chan error, 1),
+		donec: make(chan struct{}),
+	}
+	go fp.run()
+	return fp
+}
+
+// Open returns a fresh file for writing. Rename the file before calling
+// Open again or there will be file collisions.
+// it will 'block' if the tmp file lock is already taken.
+func (fp *filePipeline) Open() (f *fileutil.LockedFile, err error) {
+	select {
+	case f = <-fp.filec:
+	case err = <-fp.errc:
+	}
+	return f, err
+}
+
+func (fp *filePipeline) Close() error {
+	close(fp.donec)
+	return <-fp.errc
+}
+
+func (fp *filePipeline) alloc() (f *fileutil.LockedFile, err error) {
+	// count % 2 so this file isn't the same as the one last published
+	fpath := filepath.Join(fp.dir, fmt.Sprintf("%d.tmp", fp.count%2))
+	if f, err = createNewWALFile[*fileutil.LockedFile](fpath, false); err != nil {
+		return nil, err
+	}
+	if err = fileutil.Preallocate(f.File, fp.size, true); err != nil {
+		fp.lg.Error("failed to preallocate space when creating a new WAL", zap.Int64("size", fp.size), zap.Error(err))
+		f.Close()
+		return nil, err
+	}
+	fp.count++
+	return f, nil
+}
+
+func (fp *filePipeline) run() {
+	defer close(fp.errc)
+	for {
+		f, err := fp.alloc()
+		if err != nil {
+			fp.errc <- err
+			return
+		}
+		select {
+		case fp.filec <- f:
+		case <-fp.donec:
+			os.Remove(f.Name())
+			f.Close()
+			return
+		}
+	}
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/wal/metrics.go b/vendor/go.etcd.io/etcd/server/v3/storage/wal/metrics.go
new file mode 100644
index 0000000..6f09deb
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/wal/metrics.go
@@ -0,0 +1,52 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package wal
+
+import "github.com/prometheus/client_golang/prometheus"
+
+var (
+	walFsyncSec = prometheus.NewHistogram(prometheus.HistogramOpts{
+		Namespace: "etcd",
+		Subsystem: "disk",
+		Name:      "wal_fsync_duration_seconds",
+		Help:      "The latency distributions of fsync called by WAL.",
+
+		// lowest bucket start of upper bound 0.001 sec (1 ms) with factor 2
+		// highest bucket start of 0.001 sec * 2^13 == 8.192 sec
+		Buckets: prometheus.ExponentialBuckets(0.001, 2, 14),
+	})
+
+	walWriteSec = prometheus.NewHistogram(prometheus.HistogramOpts{
+		Namespace: "etcd",
+		Subsystem: "disk",
+		Name:      "wal_write_duration_seconds",
+		Help:      "The latency distributions of write called by WAL.",
+
+		Buckets: prometheus.ExponentialBuckets(0.001, 2, 14),
+	})
+
+	walWriteBytes = prometheus.NewGauge(prometheus.GaugeOpts{
+		Namespace: "etcd",
+		Subsystem: "disk",
+		Name:      "wal_write_bytes_total",
+		Help:      "Total number of bytes written in WAL.",
+	})
+)
+
+func init() {
+	prometheus.MustRegister(walFsyncSec)
+	prometheus.MustRegister(walWriteSec)
+	prometheus.MustRegister(walWriteBytes)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/wal/repair.go b/vendor/go.etcd.io/etcd/server/v3/storage/wal/repair.go
new file mode 100644
index 0000000..1627754
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/wal/repair.go
@@ -0,0 +1,117 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package wal
+
+import (
+	"errors"
+	"io"
+	"os"
+	"path/filepath"
+	"time"
+
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/client/pkg/v3/fileutil"
+	"go.etcd.io/etcd/server/v3/storage/wal/walpb"
+)
+
+// Repair tries to repair ErrUnexpectedEOF in the
+// last wal file by truncating.
+func Repair(lg *zap.Logger, dirpath string) bool {
+	if lg == nil {
+		lg = zap.NewNop()
+	}
+	f, err := openLast(lg, dirpath)
+	if err != nil {
+		return false
+	}
+	defer f.Close()
+
+	lg.Info("repairing", zap.String("path", f.Name()))
+
+	rec := &walpb.Record{}
+	decoder := NewDecoder(fileutil.NewFileReader(f.File))
+	for {
+		lastOffset := decoder.LastOffset()
+		err := decoder.Decode(rec)
+		switch {
+		case err == nil:
+			// update crc of the decoder when necessary
+			switch rec.Type {
+			case CrcType:
+				crc := decoder.LastCRC()
+				// current crc of decoder must match the crc of the record.
+				// do no need to match 0 crc, since the decoder is a new one at this case.
+				if crc != 0 && rec.Validate(crc) != nil {
+					return false
+				}
+				decoder.UpdateCRC(rec.Crc)
+			}
+			continue
+
+		case errors.Is(err, io.EOF):
+			lg.Info("repaired", zap.String("path", f.Name()), zap.Error(io.EOF))
+			return true
+
+		case errors.Is(err, io.ErrUnexpectedEOF):
+			brokenName := f.Name() + ".broken"
+			bf, bferr := createNewWALFile[*os.File](brokenName, true)
+			if bferr != nil {
+				lg.Warn("failed to create backup file", zap.String("path", brokenName), zap.Error(bferr))
+				return false
+			}
+			defer bf.Close()
+
+			if _, err = f.Seek(0, io.SeekStart); err != nil {
+				lg.Warn("failed to read file", zap.String("path", f.Name()), zap.Error(err))
+				return false
+			}
+
+			if _, err = io.Copy(bf, f); err != nil {
+				lg.Warn("failed to copy", zap.String("from", f.Name()), zap.String("to", brokenName), zap.Error(err))
+				return false
+			}
+
+			if err = f.Truncate(lastOffset); err != nil {
+				lg.Warn("failed to truncate", zap.String("path", f.Name()), zap.Error(err))
+				return false
+			}
+
+			start := time.Now()
+			if err = fileutil.Fsync(f.File); err != nil {
+				lg.Warn("failed to fsync", zap.String("path", f.Name()), zap.Error(err))
+				return false
+			}
+			walFsyncSec.Observe(time.Since(start).Seconds())
+
+			lg.Info("repaired", zap.String("path", f.Name()), zap.Error(io.ErrUnexpectedEOF))
+			return true
+
+		default:
+			lg.Warn("failed to repair", zap.String("path", f.Name()), zap.Error(err))
+			return false
+		}
+	}
+}
+
+// openLast opens the last wal file for read and write.
+func openLast(lg *zap.Logger, dirpath string) (*fileutil.LockedFile, error) {
+	names, err := readWALNames(lg, dirpath)
+	if err != nil {
+		return nil, err
+	}
+	last := filepath.Join(dirpath, names[len(names)-1])
+	return fileutil.LockFile(last, os.O_RDWR, fileutil.PrivateFileMode)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/wal/util.go b/vendor/go.etcd.io/etcd/server/v3/storage/wal/util.go
new file mode 100644
index 0000000..8dec85c
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/wal/util.go
@@ -0,0 +1,112 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package wal
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/client/pkg/v3/fileutil"
+)
+
+var errBadWALName = errors.New("bad wal name")
+
+// Exist returns true if there are any files in a given directory.
+func Exist(dir string) bool {
+	names, err := fileutil.ReadDir(dir, fileutil.WithExt(".wal"))
+	if err != nil {
+		return false
+	}
+	return len(names) != 0
+}
+
+// searchIndex returns the last array index of names whose raft index section is
+// equal to or smaller than the given index.
+// The given names MUST be sorted.
+func searchIndex(lg *zap.Logger, names []string, index uint64) (int, bool) {
+	for i := len(names) - 1; i >= 0; i-- {
+		name := names[i]
+		_, curIndex, err := parseWALName(name)
+		if err != nil {
+			lg.Panic("failed to parse WAL file name", zap.String("path", name), zap.Error(err))
+		}
+		if index >= curIndex {
+			return i, true
+		}
+	}
+	return -1, false
+}
+
+// names should have been sorted based on sequence number.
+// isValidSeq checks whether seq increases continuously.
+func isValidSeq(lg *zap.Logger, names []string) bool {
+	var lastSeq uint64
+	for _, name := range names {
+		curSeq, _, err := parseWALName(name)
+		if err != nil {
+			lg.Panic("failed to parse WAL file name", zap.String("path", name), zap.Error(err))
+		}
+		if lastSeq != 0 && lastSeq != curSeq-1 {
+			return false
+		}
+		lastSeq = curSeq
+	}
+	return true
+}
+
+func readWALNames(lg *zap.Logger, dirpath string) ([]string, error) {
+	names, err := fileutil.ReadDir(dirpath)
+	if err != nil {
+		return nil, fmt.Errorf("[readWALNames] fileutil.ReadDir failed: %w", err)
+	}
+	wnames := checkWALNames(lg, names)
+	if len(wnames) == 0 {
+		return nil, ErrFileNotFound
+	}
+	return wnames, nil
+}
+
+func checkWALNames(lg *zap.Logger, names []string) []string {
+	wnames := make([]string, 0)
+	for _, name := range names {
+		if _, _, err := parseWALName(name); err != nil {
+			// don't complain about left over tmp files
+			if !strings.HasSuffix(name, ".tmp") {
+				lg.Warn(
+					"ignored file in WAL directory",
+					zap.String("path", name),
+				)
+			}
+			continue
+		}
+		wnames = append(wnames, name)
+	}
+	return wnames
+}
+
+func parseWALName(str string) (seq, index uint64, err error) {
+	if !strings.HasSuffix(str, ".wal") {
+		return 0, 0, errBadWALName
+	}
+	_, err = fmt.Sscanf(str, "%016x-%016x.wal", &seq, &index)
+	return seq, index, err
+}
+
+func walName(seq, index uint64) string {
+	return fmt.Sprintf("%016x-%016x.wal", seq, index)
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/wal/version.go b/vendor/go.etcd.io/etcd/server/v3/storage/wal/version.go
new file mode 100644
index 0000000..b592fd2
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/wal/version.go
@@ -0,0 +1,288 @@
+// Copyright 2021 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package wal
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/coreos/go-semver/semver"
+	"github.com/golang/protobuf/proto"
+	"google.golang.org/protobuf/reflect/protoreflect"
+	"google.golang.org/protobuf/types/descriptorpb"
+
+	"go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/api/v3/version"
+	"go.etcd.io/etcd/pkg/v3/pbutil"
+	"go.etcd.io/raft/v3/raftpb"
+)
+
+// Version defines the wal version interface.
+type Version interface {
+	// MinimalEtcdVersion returns minimal etcd version able to interpret WAL log.
+	MinimalEtcdVersion() *semver.Version
+}
+
+// ReadWALVersion reads remaining entries from opened WAL and returns struct
+// that implements schema.WAL interface.
+func ReadWALVersion(w *WAL) (Version, error) {
+	_, _, ents, err := w.ReadAll()
+	if err != nil {
+		return nil, err
+	}
+	return &walVersion{entries: ents}, nil
+}
+
+type walVersion struct {
+	entries []raftpb.Entry
+}
+
+// MinimalEtcdVersion returns minimal etcd able to interpret entries from  WAL log,
+func (w *walVersion) MinimalEtcdVersion() *semver.Version {
+	return MinimalEtcdVersion(w.entries)
+}
+
+// MinimalEtcdVersion returns minimal etcd able to interpret entries from  WAL log,
+// determined by looking at entries since the last snapshot and returning the highest
+// etcd version annotation from used messages, fields, enums and their values.
+func MinimalEtcdVersion(ents []raftpb.Entry) *semver.Version {
+	var maxVer *semver.Version
+	for _, ent := range ents {
+		err := visitEntry(ent, func(path protoreflect.FullName, ver *semver.Version) error {
+			maxVer = maxVersion(maxVer, ver)
+			return nil
+		})
+		if err != nil {
+			panic(err)
+		}
+	}
+	return maxVer
+}
+
+type Visitor func(path protoreflect.FullName, ver *semver.Version) error
+
+// VisitFileDescriptor calls visitor on each field and enum value with etcd version read from proto definition.
+// If field/enum value is not annotated, visitor will be called with nil.
+// Upon encountering invalid annotation, will immediately exit with error.
+func VisitFileDescriptor(file protoreflect.FileDescriptor, visitor Visitor) error {
+	msgs := file.Messages()
+	for i := 0; i < msgs.Len(); i++ {
+		err := visitMessageDescriptor(msgs.Get(i), visitor)
+		if err != nil {
+			return err
+		}
+	}
+	enums := file.Enums()
+	for i := 0; i < enums.Len(); i++ {
+		err := visitEnumDescriptor(enums.Get(i), visitor)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func visitEntry(ent raftpb.Entry, visitor Visitor) error {
+	err := visitMessage(proto.MessageReflect(&ent), visitor)
+	if err != nil {
+		return err
+	}
+	return visitEntryData(ent.Type, ent.Data, visitor)
+}
+
+func visitEntryData(entryType raftpb.EntryType, data []byte, visitor Visitor) error {
+	var msg protoreflect.Message
+	switch entryType {
+	case raftpb.EntryNormal:
+		var raftReq etcdserverpb.InternalRaftRequest
+		if err := pbutil.Unmarshaler(&raftReq).Unmarshal(data); err != nil {
+			// try V2 Request
+			var r etcdserverpb.Request
+			if pbutil.Unmarshaler(&r).Unmarshal(data) != nil {
+				// return original error
+				return err
+			}
+			msg = proto.MessageReflect(&r)
+			break
+		}
+		msg = proto.MessageReflect(&raftReq)
+		if raftReq.DowngradeVersionTest != nil {
+			ver, err := semver.NewVersion(raftReq.DowngradeVersionTest.Ver)
+			if err != nil {
+				return err
+			}
+			err = visitor(msg.Descriptor().FullName(), ver)
+			if err != nil {
+				return err
+			}
+		}
+	case raftpb.EntryConfChange:
+		var confChange raftpb.ConfChange
+		err := pbutil.Unmarshaler(&confChange).Unmarshal(data)
+		if err != nil {
+			return nil
+		}
+		msg = proto.MessageReflect(&confChange)
+		return visitor(msg.Descriptor().FullName(), &version.V3_0)
+	case raftpb.EntryConfChangeV2:
+		var confChange raftpb.ConfChangeV2
+		err := pbutil.Unmarshaler(&confChange).Unmarshal(data)
+		if err != nil {
+			return nil
+		}
+		msg = proto.MessageReflect(&confChange)
+		return visitor(msg.Descriptor().FullName(), &version.V3_4)
+	default:
+		panic("unhandled")
+	}
+	return visitMessage(msg, visitor)
+}
+
+func visitMessageDescriptor(md protoreflect.MessageDescriptor, visitor Visitor) error {
+	err := visitDescriptor(md, visitor)
+	if err != nil {
+		return err
+	}
+	fields := md.Fields()
+	for i := 0; i < fields.Len(); i++ {
+		fd := fields.Get(i)
+		err = visitDescriptor(fd, visitor)
+		if err != nil {
+			return err
+		}
+	}
+
+	enums := md.Enums()
+	for i := 0; i < enums.Len(); i++ {
+		err = visitEnumDescriptor(enums.Get(i), visitor)
+		if err != nil {
+			return err
+		}
+	}
+	return err
+}
+
+func visitMessage(m protoreflect.Message, visitor Visitor) error {
+	md := m.Descriptor()
+	err := visitDescriptor(md, visitor)
+	if err != nil {
+		return err
+	}
+	m.Range(func(field protoreflect.FieldDescriptor, value protoreflect.Value) bool {
+		fd := md.Fields().Get(field.Index())
+		err = visitDescriptor(fd, visitor)
+		if err != nil {
+			return false
+		}
+
+		switch m := value.Interface().(type) {
+		case protoreflect.Message:
+			err = visitMessage(m, visitor)
+		case protoreflect.EnumNumber:
+			err = visitEnumNumber(fd.Enum(), m, visitor)
+		}
+		return err == nil
+	})
+	return err
+}
+
+func visitEnumDescriptor(enum protoreflect.EnumDescriptor, visitor Visitor) error {
+	err := visitDescriptor(enum, visitor)
+	if err != nil {
+		return err
+	}
+	fields := enum.Values()
+	for i := 0; i < fields.Len(); i++ {
+		fd := fields.Get(i)
+		err = visitDescriptor(fd, visitor)
+		if err != nil {
+			return err
+		}
+	}
+	return err
+}
+
+func visitEnumNumber(enum protoreflect.EnumDescriptor, number protoreflect.EnumNumber, visitor Visitor) error {
+	err := visitDescriptor(enum, visitor)
+	if err != nil {
+		return err
+	}
+	intNumber := int(number)
+	fields := enum.Values()
+	if intNumber >= fields.Len() || intNumber < 0 {
+		return fmt.Errorf("could not visit EnumNumber [%d]", intNumber)
+	}
+	return visitEnumValue(fields.Get(intNumber), visitor)
+}
+
+func visitEnumValue(enum protoreflect.EnumValueDescriptor, visitor Visitor) error {
+	valueOpts := enum.Options().(*descriptorpb.EnumValueOptions)
+	if valueOpts != nil {
+		ver, _ := etcdVersionFromOptionsString(valueOpts.String())
+		err := visitor(enum.FullName(), ver)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func visitDescriptor(md protoreflect.Descriptor, visitor Visitor) error {
+	opts, ok := md.Options().(fmt.Stringer)
+	if !ok {
+		return nil
+	}
+	ver, err := etcdVersionFromOptionsString(opts.String())
+	if err != nil {
+		return fmt.Errorf("%s: %w", md.FullName(), err)
+	}
+	return visitor(md.FullName(), ver)
+}
+
+func maxVersion(a *semver.Version, b *semver.Version) *semver.Version {
+	if a != nil && (b == nil || b.LessThan(*a)) {
+		return a
+	}
+	return b
+}
+
+func etcdVersionFromOptionsString(opts string) (*semver.Version, error) {
+	// TODO: Use proto.GetExtention when gogo/protobuf is usable with protoreflect
+	msgs := []string{"[versionpb.etcd_version_msg]:", "[versionpb.etcd_version_field]:", "[versionpb.etcd_version_enum]:", "[versionpb.etcd_version_enum_value]:"}
+	var end, index int
+	for _, msg := range msgs {
+		index = strings.Index(opts, msg)
+		end = index + len(msg)
+		if index != -1 {
+			break
+		}
+	}
+	if index == -1 {
+		return nil, nil
+	}
+	var verStr string
+	_, err := fmt.Sscanf(opts[end:], "%q", &verStr)
+	if err != nil {
+		return nil, err
+	}
+	if strings.Count(verStr, ".") == 1 {
+		verStr = verStr + ".0"
+	}
+	ver, err := semver.NewVersion(verStr)
+	if err != nil {
+		return nil, err
+	}
+	return ver, nil
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/wal/wal.go b/vendor/go.etcd.io/etcd/server/v3/storage/wal/wal.go
new file mode 100644
index 0000000..f3d7bc5
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/wal/wal.go
@@ -0,0 +1,1049 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package wal
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"hash/crc32"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+	"time"
+
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/client/pkg/v3/fileutil"
+	"go.etcd.io/etcd/pkg/v3/pbutil"
+	"go.etcd.io/etcd/server/v3/storage/wal/walpb"
+	"go.etcd.io/raft/v3"
+	"go.etcd.io/raft/v3/raftpb"
+)
+
+const (
+	MetadataType int64 = iota + 1
+	EntryType
+	StateType
+	CrcType
+	SnapshotType
+
+	// warnSyncDuration is the amount of time allotted to an fsync before
+	// logging a warning
+	warnSyncDuration = time.Second
+)
+
+var (
+	// SegmentSizeBytes is the preallocated size of each wal segment file.
+	// The actual size might be larger than this. In general, the default
+	// value should be used, but this is defined as an exported variable
+	// so that tests can set a different segment size.
+	SegmentSizeBytes int64 = 64 * 1000 * 1000 // 64MB
+
+	ErrMetadataConflict = errors.New("wal: conflicting metadata found")
+	ErrFileNotFound     = errors.New("wal: file not found")
+	ErrCRCMismatch      = walpb.ErrCRCMismatch
+	ErrSnapshotMismatch = errors.New("wal: snapshot mismatch")
+	ErrSnapshotNotFound = errors.New("wal: snapshot not found")
+	ErrSliceOutOfRange  = errors.New("wal: slice bounds out of range")
+	ErrDecoderNotFound  = errors.New("wal: decoder not found")
+	crcTable            = crc32.MakeTable(crc32.Castagnoli)
+)
+
+// WAL is a logical representation of the stable storage.
+// WAL is either in read mode or append mode but not both.
+// A newly created WAL is in append mode, and ready for appending records.
+// A just opened WAL is in read mode, and ready for reading records.
+// The WAL will be ready for appending after reading out all the previous records.
+type WAL struct {
+	lg *zap.Logger
+
+	dir string // the living directory of the underlay files
+
+	// dirFile is a fd for the wal directory for syncing on Rename
+	dirFile *os.File
+
+	metadata []byte           // metadata recorded at the head of each WAL
+	state    raftpb.HardState // hardstate recorded at the head of WAL
+
+	start     walpb.Snapshot // snapshot to start reading
+	decoder   Decoder        // decoder to Decode records
+	readClose func() error   // closer for Decode reader
+
+	unsafeNoSync bool // if set, do not fsync
+
+	mu      sync.Mutex
+	enti    uint64   // index of the last entry saved to the wal
+	encoder *encoder // encoder to encode records
+
+	locks []*fileutil.LockedFile // the locked files the WAL holds (the name is increasing)
+	fp    *filePipeline
+}
+
+// Create creates a WAL ready for appending records. The given metadata is
+// recorded at the head of each WAL file, and can be retrieved with ReadAll
+// after the file is Open.
+func Create(lg *zap.Logger, dirpath string, metadata []byte) (*WAL, error) {
+	if Exist(dirpath) {
+		return nil, os.ErrExist
+	}
+
+	if lg == nil {
+		lg = zap.NewNop()
+	}
+
+	// keep temporary wal directory so WAL initialization appears atomic
+	tmpdirpath := filepath.Clean(dirpath) + ".tmp"
+	if fileutil.Exist(tmpdirpath) {
+		if err := os.RemoveAll(tmpdirpath); err != nil {
+			return nil, err
+		}
+	}
+	defer os.RemoveAll(tmpdirpath)
+
+	if err := fileutil.CreateDirAll(lg, tmpdirpath); err != nil {
+		lg.Warn(
+			"failed to create a temporary WAL directory",
+			zap.String("tmp-dir-path", tmpdirpath),
+			zap.String("dir-path", dirpath),
+			zap.Error(err),
+		)
+		return nil, err
+	}
+
+	p := filepath.Join(tmpdirpath, walName(0, 0))
+	f, err := createNewWALFile[*fileutil.LockedFile](p, false)
+	if err != nil {
+		lg.Warn(
+			"failed to flock an initial WAL file",
+			zap.String("path", p),
+			zap.Error(err),
+		)
+		return nil, err
+	}
+	if _, err = f.Seek(0, io.SeekEnd); err != nil {
+		lg.Warn(
+			"failed to seek an initial WAL file",
+			zap.String("path", p),
+			zap.Error(err),
+		)
+		return nil, err
+	}
+	if err = fileutil.Preallocate(f.File, SegmentSizeBytes, true); err != nil {
+		lg.Warn(
+			"failed to preallocate an initial WAL file",
+			zap.String("path", p),
+			zap.Int64("segment-bytes", SegmentSizeBytes),
+			zap.Error(err),
+		)
+		return nil, err
+	}
+
+	w := &WAL{
+		lg:       lg,
+		dir:      dirpath,
+		metadata: metadata,
+	}
+	w.encoder, err = newFileEncoder(f.File, 0)
+	if err != nil {
+		return nil, err
+	}
+	w.locks = append(w.locks, f)
+	if err = w.saveCrc(0); err != nil {
+		return nil, err
+	}
+	if err = w.encoder.encode(&walpb.Record{Type: MetadataType, Data: metadata}); err != nil {
+		return nil, err
+	}
+	if err = w.SaveSnapshot(walpb.Snapshot{}); err != nil {
+		return nil, err
+	}
+
+	logDirPath := w.dir
+	if w, err = w.renameWAL(tmpdirpath); err != nil {
+		lg.Warn(
+			"failed to rename the temporary WAL directory",
+			zap.String("tmp-dir-path", tmpdirpath),
+			zap.String("dir-path", logDirPath),
+			zap.Error(err),
+		)
+		return nil, err
+	}
+
+	var perr error
+	defer func() {
+		if perr != nil {
+			w.cleanupWAL(lg)
+		}
+	}()
+
+	// directory was renamed; sync parent dir to persist rename
+	pdir, perr := fileutil.OpenDir(filepath.Dir(w.dir))
+	if perr != nil {
+		lg.Warn(
+			"failed to open the parent data directory",
+			zap.String("parent-dir-path", filepath.Dir(w.dir)),
+			zap.String("dir-path", w.dir),
+			zap.Error(perr),
+		)
+		return nil, perr
+	}
+	dirCloser := func() error {
+		if perr = pdir.Close(); perr != nil {
+			lg.Warn(
+				"failed to close the parent data directory file",
+				zap.String("parent-dir-path", filepath.Dir(w.dir)),
+				zap.String("dir-path", w.dir),
+				zap.Error(perr),
+			)
+			return perr
+		}
+		return nil
+	}
+	start := time.Now()
+	if perr = fileutil.Fsync(pdir); perr != nil {
+		dirCloser()
+		lg.Warn(
+			"failed to fsync the parent data directory file",
+			zap.String("parent-dir-path", filepath.Dir(w.dir)),
+			zap.String("dir-path", w.dir),
+			zap.Error(perr),
+		)
+		return nil, perr
+	}
+	walFsyncSec.Observe(time.Since(start).Seconds())
+	if err = dirCloser(); err != nil {
+		return nil, err
+	}
+
+	return w, nil
+}
+
+// createNewWALFile creates a WAL file.
+// To create a locked file, use *fileutil.LockedFile type parameter.
+// To create a standard file, use *os.File type parameter.
+// If forceNew is true, the file will be truncated if it already exists.
+func createNewWALFile[T *os.File | *fileutil.LockedFile](path string, forceNew bool) (T, error) {
+	flag := os.O_WRONLY | os.O_CREATE
+	if forceNew {
+		flag |= os.O_TRUNC
+	}
+
+	if _, isLockedFile := any(T(nil)).(*fileutil.LockedFile); isLockedFile {
+		lockedFile, err := fileutil.LockFile(path, flag, fileutil.PrivateFileMode)
+		if err != nil {
+			return nil, err
+		}
+		return any(lockedFile).(T), nil
+	}
+
+	file, err := os.OpenFile(path, flag, fileutil.PrivateFileMode)
+	if err != nil {
+		return nil, err
+	}
+	return any(file).(T), nil
+}
+
+func (w *WAL) Reopen(lg *zap.Logger, snap walpb.Snapshot) (*WAL, error) {
+	err := w.Close()
+	if err != nil {
+		lg.Panic("failed to close WAL during reopen", zap.Error(err))
+	}
+	return Open(lg, w.dir, snap)
+}
+
+func (w *WAL) SetUnsafeNoFsync() {
+	w.unsafeNoSync = true
+}
+
+func (w *WAL) cleanupWAL(lg *zap.Logger) {
+	var err error
+	if err = w.Close(); err != nil {
+		lg.Panic("failed to close WAL during cleanup", zap.Error(err))
+	}
+	brokenDirName := fmt.Sprintf("%s.broken.%v", w.dir, time.Now().Format("20060102.150405.999999"))
+	if err = os.Rename(w.dir, brokenDirName); err != nil {
+		lg.Panic(
+			"failed to rename WAL during cleanup",
+			zap.Error(err),
+			zap.String("source-path", w.dir),
+			zap.String("rename-path", brokenDirName),
+		)
+	}
+}
+
+func (w *WAL) renameWAL(tmpdirpath string) (*WAL, error) {
+	if err := os.RemoveAll(w.dir); err != nil {
+		return nil, err
+	}
+	// On non-Windows platforms, hold the lock while renaming. Releasing
+	// the lock and trying to reacquire it quickly can be flaky because
+	// it's possible the process will fork to spawn a process while this is
+	// happening. The fds are set up as close-on-exec by the Go runtime,
+	// but there is a window between the fork and the exec where another
+	// process holds the lock.
+	if err := os.Rename(tmpdirpath, w.dir); err != nil {
+		var linkErr *os.LinkError
+		if errors.As(err, &linkErr) {
+			return w.renameWALUnlock(tmpdirpath)
+		}
+		return nil, err
+	}
+	w.fp = newFilePipeline(w.lg, w.dir, SegmentSizeBytes)
+	df, err := fileutil.OpenDir(w.dir)
+	w.dirFile = df
+	return w, err
+}
+
+func (w *WAL) renameWALUnlock(tmpdirpath string) (*WAL, error) {
+	// rename of directory with locked files doesn't work on windows/cifs;
+	// close the WAL to release the locks so the directory can be renamed.
+	w.lg.Info(
+		"closing WAL to release flock and retry directory renaming",
+		zap.String("from", tmpdirpath),
+		zap.String("to", w.dir),
+	)
+	w.Close()
+
+	if err := os.Rename(tmpdirpath, w.dir); err != nil {
+		return nil, err
+	}
+
+	// reopen and relock
+	newWAL, oerr := Open(w.lg, w.dir, walpb.Snapshot{})
+	if oerr != nil {
+		return nil, oerr
+	}
+	if _, _, _, err := newWAL.ReadAll(); err != nil {
+		newWAL.Close()
+		return nil, err
+	}
+	return newWAL, nil
+}
+
+// Open opens the WAL at the given snap.
+// The snap SHOULD have been previously saved to the WAL, or the following
+// ReadAll will fail.
+// The returned WAL is ready to read and the first record will be the one after
+// the given snap. The WAL cannot be appended to before reading out all of its
+// previous records.
+func Open(lg *zap.Logger, dirpath string, snap walpb.Snapshot) (*WAL, error) {
+	w, err := openAtIndex(lg, dirpath, snap, true)
+	if err != nil {
+		return nil, fmt.Errorf("openAtIndex failed: %w", err)
+	}
+	if w.dirFile, err = fileutil.OpenDir(w.dir); err != nil {
+		return nil, fmt.Errorf("fileutil.OpenDir failed: %w", err)
+	}
+	return w, nil
+}
+
+// OpenForRead only opens the wal files for read.
+// Write on a read only wal panics.
+func OpenForRead(lg *zap.Logger, dirpath string, snap walpb.Snapshot) (*WAL, error) {
+	return openAtIndex(lg, dirpath, snap, false)
+}
+
+func openAtIndex(lg *zap.Logger, dirpath string, snap walpb.Snapshot, write bool) (*WAL, error) {
+	if lg == nil {
+		lg = zap.NewNop()
+	}
+	names, nameIndex, err := selectWALFiles(lg, dirpath, snap)
+	if err != nil {
+		return nil, fmt.Errorf("[openAtIndex] selectWALFiles failed: %w", err)
+	}
+
+	rs, ls, closer, err := openWALFiles(lg, dirpath, names, nameIndex, write)
+	if err != nil {
+		return nil, fmt.Errorf("[openAtIndex] openWALFiles failed: %w", err)
+	}
+
+	// create a WAL ready for reading
+	w := &WAL{
+		lg:        lg,
+		dir:       dirpath,
+		start:     snap,
+		decoder:   NewDecoder(rs...),
+		readClose: closer,
+		locks:     ls,
+	}
+
+	if write {
+		// write reuses the file descriptors from read; don't close so
+		// WAL can append without dropping the file lock
+		w.readClose = nil
+		if _, _, err := parseWALName(filepath.Base(w.tail().Name())); err != nil {
+			closer()
+			return nil, fmt.Errorf("[openAtIndex] parseWALName failed: %w", err)
+		}
+		w.fp = newFilePipeline(lg, w.dir, SegmentSizeBytes)
+	}
+
+	return w, nil
+}
+
+func selectWALFiles(lg *zap.Logger, dirpath string, snap walpb.Snapshot) ([]string, int, error) {
+	names, err := readWALNames(lg, dirpath)
+	if err != nil {
+		return nil, -1, fmt.Errorf("readWALNames failed: %w", err)
+	}
+
+	nameIndex, ok := searchIndex(lg, names, snap.Index)
+	if !ok {
+		return nil, -1, fmt.Errorf("wal: file not found which matches the snapshot index '%d'", snap.Index)
+	}
+
+	if !isValidSeq(lg, names[nameIndex:]) {
+		return nil, -1, fmt.Errorf("wal: file sequence numbers (starting from %d) do not increase continuously", nameIndex)
+	}
+
+	return names, nameIndex, nil
+}
+
+func openWALFiles(lg *zap.Logger, dirpath string, names []string, nameIndex int, write bool) ([]fileutil.FileReader, []*fileutil.LockedFile, func() error, error) {
+	rcs := make([]io.ReadCloser, 0)
+	rs := make([]fileutil.FileReader, 0)
+	ls := make([]*fileutil.LockedFile, 0)
+	for _, name := range names[nameIndex:] {
+		p := filepath.Join(dirpath, name)
+		var f *os.File
+		if write {
+			l, err := fileutil.TryLockFile(p, os.O_RDWR, fileutil.PrivateFileMode)
+			if err != nil {
+				closeAll(lg, rcs...)
+				return nil, nil, nil, fmt.Errorf("[openWALFiles] fileutil.TryLockFile failed: %w", err)
+			}
+			ls = append(ls, l)
+			rcs = append(rcs, l)
+			f = l.File
+		} else {
+			rf, err := os.OpenFile(p, os.O_RDONLY, fileutil.PrivateFileMode)
+			if err != nil {
+				closeAll(lg, rcs...)
+				return nil, nil, nil, fmt.Errorf("[openWALFiles] os.OpenFile failed (%q): %w", p, err)
+			}
+			ls = append(ls, nil)
+			rcs = append(rcs, rf)
+			f = rf
+		}
+		fileReader := fileutil.NewFileReader(f)
+		rs = append(rs, fileReader)
+	}
+
+	closer := func() error { return closeAll(lg, rcs...) }
+
+	return rs, ls, closer, nil
+}
+
+// ReadAll reads out records of the current WAL.
+// If opened in write mode, it must read out all records until EOF. Or an error
+// will be returned.
+// If opened in read mode, it will try to read all records if possible.
+// If it cannot read out the expected snap, it will return ErrSnapshotNotFound.
+// If loaded snap doesn't match with the expected one, it will return
+// all the records and error ErrSnapshotMismatch.
+// TODO: detect not-last-snap error.
+// TODO: maybe loose the checking of match.
+// After ReadAll, the WAL will be ready for appending new records.
+//
+// ReadAll suppresses WAL entries that got overridden (i.e. a newer entry with the same index
+// exists in the log). Such a situation can happen in cases described in figure 7. of the
+// RAFT paper (http://web.stanford.edu/~ouster/cgi-bin/papers/raft-atc14.pdf).
+//
+// ReadAll may return uncommitted yet entries, that are subject to be overridden.
+// Do not apply entries that have index > state.commit, as they are subject to change.
+func (w *WAL) ReadAll() (metadata []byte, state raftpb.HardState, ents []raftpb.Entry, err error) {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+
+	rec := &walpb.Record{}
+
+	if w.decoder == nil {
+		return nil, state, nil, ErrDecoderNotFound
+	}
+	decoder := w.decoder
+
+	var match bool
+	for err = decoder.Decode(rec); err == nil; err = decoder.Decode(rec) {
+		switch rec.Type {
+		case EntryType:
+			e := MustUnmarshalEntry(rec.Data)
+			// 0 <= e.Index-w.start.Index - 1 < len(ents)
+			if e.Index > w.start.Index {
+				// prevent "panic: runtime error: slice bounds out of range [:13038096702221461992] with capacity 0"
+				offset := e.Index - w.start.Index - 1
+				if offset > uint64(len(ents)) {
+					// return error before append call causes runtime panic.
+					// We still return the continuous WAL entries that have already been read.
+					// Refer to https://github.com/etcd-io/etcd/pull/19038#issuecomment-2557414292.
+					return nil, state, ents, fmt.Errorf("%w, snapshot[Index: %d, Term: %d], current entry[Index: %d, Term: %d], len(ents): %d",
+						ErrSliceOutOfRange, w.start.Index, w.start.Term, e.Index, e.Term, len(ents))
+				}
+				// The line below is potentially overriding some 'uncommitted' entries.
+				ents = append(ents[:offset], e)
+			}
+			w.enti = e.Index
+
+		case StateType:
+			state = MustUnmarshalState(rec.Data)
+
+		case MetadataType:
+			if metadata != nil && !bytes.Equal(metadata, rec.Data) {
+				state.Reset()
+				return nil, state, nil, ErrMetadataConflict
+			}
+			metadata = rec.Data
+
+		case CrcType:
+			crc := decoder.LastCRC()
+			// current crc of decoder must match the crc of the record.
+			// do no need to match 0 crc, since the decoder is a new one at this case.
+			if crc != 0 && rec.Validate(crc) != nil {
+				state.Reset()
+				return nil, state, nil, ErrCRCMismatch
+			}
+			decoder.UpdateCRC(rec.Crc)
+
+		case SnapshotType:
+			var snap walpb.Snapshot
+			pbutil.MustUnmarshal(&snap, rec.Data)
+			if snap.Index == w.start.Index {
+				if snap.Term != w.start.Term {
+					state.Reset()
+					return nil, state, nil, ErrSnapshotMismatch
+				}
+				match = true
+			}
+
+		default:
+			state.Reset()
+			return nil, state, nil, fmt.Errorf("unexpected block type %d", rec.Type)
+		}
+	}
+
+	switch w.tail() {
+	case nil:
+		// We do not have to read out all entries in read mode.
+		// The last record maybe a partial written one, so
+		// `io.ErrUnexpectedEOF` might be returned.
+		if !errors.Is(err, io.EOF) && !errors.Is(err, io.ErrUnexpectedEOF) {
+			state.Reset()
+			return nil, state, nil, err
+		}
+	default:
+		// We must read all the entries if WAL is opened in write mode.
+		if !errors.Is(err, io.EOF) {
+			state.Reset()
+			return nil, state, nil, err
+		}
+		// decodeRecord() will return io.EOF if it detects a zero record,
+		// but this zero record may be followed by non-zero records from
+		// a torn write. Overwriting some of these non-zero records, but
+		// not all, will cause CRC errors on WAL open. Since the records
+		// were never fully synced to disk in the first place, it's safe
+		// to zero them out to avoid any CRC errors from new writes.
+		if _, err = w.tail().Seek(w.decoder.LastOffset(), io.SeekStart); err != nil {
+			return nil, state, nil, err
+		}
+		if err = fileutil.ZeroToEnd(w.tail().File); err != nil {
+			return nil, state, nil, err
+		}
+	}
+
+	err = nil
+	if !match {
+		err = ErrSnapshotNotFound
+	}
+
+	// close decoder, disable reading
+	if w.readClose != nil {
+		w.readClose()
+		w.readClose = nil
+	}
+	w.start = walpb.Snapshot{}
+
+	w.metadata = metadata
+
+	if w.tail() != nil {
+		// create encoder (chain crc with the decoder), enable appending
+		w.encoder, err = newFileEncoder(w.tail().File, w.decoder.LastCRC())
+		if err != nil {
+			return nil, state, nil, err
+		}
+	}
+	w.decoder = nil
+
+	return metadata, state, ents, err
+}
+
+// ValidSnapshotEntries returns all the valid snapshot entries in the wal logs in the given directory.
+// Snapshot entries are valid if their index is less than or equal to the most recent committed hardstate.
+func ValidSnapshotEntries(lg *zap.Logger, walDir string) ([]walpb.Snapshot, error) {
+	var snaps []walpb.Snapshot
+	var state raftpb.HardState
+	var err error
+
+	rec := &walpb.Record{}
+	names, err := readWALNames(lg, walDir)
+	if err != nil {
+		return nil, err
+	}
+
+	// open wal files in read mode, so that there is no conflict
+	// when the same WAL is opened elsewhere in write mode
+	rs, _, closer, err := openWALFiles(lg, walDir, names, 0, false)
+	if err != nil {
+		return nil, err
+	}
+	defer func() {
+		if closer != nil {
+			closer()
+		}
+	}()
+
+	// create a new decoder from the readers on the WAL files
+	decoder := NewDecoder(rs...)
+
+	for err = decoder.Decode(rec); err == nil; err = decoder.Decode(rec) {
+		switch rec.Type {
+		case SnapshotType:
+			var loadedSnap walpb.Snapshot
+			pbutil.MustUnmarshal(&loadedSnap, rec.Data)
+			snaps = append(snaps, loadedSnap)
+		case StateType:
+			state = MustUnmarshalState(rec.Data)
+		case CrcType:
+			crc := decoder.LastCRC()
+			// current crc of decoder must match the crc of the record.
+			// do no need to match 0 crc, since the decoder is a new one at this case.
+			if crc != 0 && rec.Validate(crc) != nil {
+				return nil, ErrCRCMismatch
+			}
+			decoder.UpdateCRC(rec.Crc)
+		}
+	}
+	// We do not have to read out all the WAL entries
+	// as the decoder is opened in read mode.
+	if !errors.Is(err, io.EOF) && !errors.Is(err, io.ErrUnexpectedEOF) {
+		return nil, err
+	}
+
+	// filter out any snaps that are newer than the committed hardstate
+	n := 0
+	for _, s := range snaps {
+		if s.Index <= state.Commit {
+			snaps[n] = s
+			n++
+		}
+	}
+	snaps = snaps[:n:n]
+	return snaps, nil
+}
+
+// Verify reads through the given WAL and verifies that it is not corrupted.
+// It creates a new decoder to read through the records of the given WAL.
+// It does not conflict with any open WAL, but it is recommended not to
+// call this function after opening the WAL for writing.
+// If it cannot read out the expected snap, it will return ErrSnapshotNotFound.
+// If the loaded snap doesn't match with the expected one, it will
+// return error ErrSnapshotMismatch.
+func Verify(lg *zap.Logger, walDir string, snap walpb.Snapshot) (*raftpb.HardState, error) {
+	var metadata []byte
+	var err error
+	var match bool
+	var state raftpb.HardState
+
+	rec := &walpb.Record{}
+
+	if lg == nil {
+		lg = zap.NewNop()
+	}
+	names, nameIndex, err := selectWALFiles(lg, walDir, snap)
+	if err != nil {
+		return nil, err
+	}
+
+	// open wal files in read mode, so that there is no conflict
+	// when the same WAL is opened elsewhere in write mode
+	rs, _, closer, err := openWALFiles(lg, walDir, names, nameIndex, false)
+	if err != nil {
+		return nil, err
+	}
+	defer func() {
+		if closer != nil {
+			closer()
+		}
+	}()
+
+	// create a new decoder from the readers on the WAL files
+	decoder := NewDecoder(rs...)
+
+	for err = decoder.Decode(rec); err == nil; err = decoder.Decode(rec) {
+		switch rec.Type {
+		case MetadataType:
+			if metadata != nil && !bytes.Equal(metadata, rec.Data) {
+				return nil, ErrMetadataConflict
+			}
+			metadata = rec.Data
+		case CrcType:
+			crc := decoder.LastCRC()
+			// Current crc of decoder must match the crc of the record.
+			// We need not match 0 crc, since the decoder is a new one at this point.
+			if crc != 0 && rec.Validate(crc) != nil {
+				return nil, ErrCRCMismatch
+			}
+			decoder.UpdateCRC(rec.Crc)
+		case SnapshotType:
+			var loadedSnap walpb.Snapshot
+			pbutil.MustUnmarshal(&loadedSnap, rec.Data)
+			if loadedSnap.Index == snap.Index {
+				if loadedSnap.Term != snap.Term {
+					return nil, ErrSnapshotMismatch
+				}
+				match = true
+			}
+		// We ignore all entry and state type records as these
+		// are not necessary for validating the WAL contents
+		case EntryType:
+		case StateType:
+			pbutil.MustUnmarshal(&state, rec.Data)
+		default:
+			return nil, fmt.Errorf("unexpected block type %d", rec.Type)
+		}
+	}
+
+	// We do not have to read out all the WAL entries
+	// as the decoder is opened in read mode.
+	if !errors.Is(err, io.EOF) && !errors.Is(err, io.ErrUnexpectedEOF) {
+		return nil, err
+	}
+
+	if !match {
+		return nil, ErrSnapshotNotFound
+	}
+
+	return &state, nil
+}
+
+// cut closes current file written and creates a new one ready to append.
+// cut first creates a temp wal file and writes necessary headers into it.
+// Then cut atomically rename temp wal file to a wal file.
+func (w *WAL) cut() error {
+	// close old wal file; truncate to avoid wasting space if an early cut
+	off, serr := w.tail().Seek(0, io.SeekCurrent)
+	if serr != nil {
+		return serr
+	}
+
+	if err := w.tail().Truncate(off); err != nil {
+		return err
+	}
+
+	if err := w.sync(); err != nil {
+		return err
+	}
+
+	fpath := filepath.Join(w.dir, walName(w.seq()+1, w.enti+1))
+
+	// create a temp wal file with name sequence + 1, or truncate the existing one
+	newTail, err := w.fp.Open()
+	if err != nil {
+		return err
+	}
+
+	// update writer and save the previous crc
+	w.locks = append(w.locks, newTail)
+	prevCrc := w.encoder.crc.Sum32()
+	w.encoder, err = newFileEncoder(w.tail().File, prevCrc)
+	if err != nil {
+		return err
+	}
+
+	if err = w.saveCrc(prevCrc); err != nil {
+		return err
+	}
+
+	if err = w.encoder.encode(&walpb.Record{Type: MetadataType, Data: w.metadata}); err != nil {
+		return err
+	}
+
+	if err = w.saveState(&w.state); err != nil {
+		return err
+	}
+
+	// atomically move temp wal file to wal file
+	if err = w.sync(); err != nil {
+		return err
+	}
+
+	off, err = w.tail().Seek(0, io.SeekCurrent)
+	if err != nil {
+		return err
+	}
+
+	if err = os.Rename(newTail.Name(), fpath); err != nil {
+		return err
+	}
+	start := time.Now()
+	if err = fileutil.Fsync(w.dirFile); err != nil {
+		return err
+	}
+	walFsyncSec.Observe(time.Since(start).Seconds())
+
+	// reopen newTail with its new path so calls to Name() match the wal filename format
+	newTail.Close()
+
+	if newTail, err = fileutil.LockFile(fpath, os.O_WRONLY, fileutil.PrivateFileMode); err != nil {
+		return err
+	}
+	if _, err = newTail.Seek(off, io.SeekStart); err != nil {
+		return err
+	}
+
+	w.locks[len(w.locks)-1] = newTail
+
+	prevCrc = w.encoder.crc.Sum32()
+	w.encoder, err = newFileEncoder(w.tail().File, prevCrc)
+	if err != nil {
+		return err
+	}
+
+	w.lg.Info("created a new WAL segment", zap.String("path", fpath))
+	return nil
+}
+
+func (w *WAL) sync() error {
+	if w.encoder != nil {
+		if err := w.encoder.flush(); err != nil {
+			return err
+		}
+	}
+
+	if w.unsafeNoSync {
+		return nil
+	}
+
+	start := time.Now()
+	err := fileutil.Fdatasync(w.tail().File)
+
+	took := time.Since(start)
+	if took > warnSyncDuration {
+		w.lg.Warn(
+			"slow fdatasync",
+			zap.Duration("took", took),
+			zap.Duration("expected-duration", warnSyncDuration),
+		)
+	}
+	walFsyncSec.Observe(took.Seconds())
+
+	return err
+}
+
+func (w *WAL) Sync() error {
+	return w.sync()
+}
+
+// ReleaseLockTo releases the locks, which has smaller index than the given index
+// except the largest one among them.
+// For example, if WAL is holding lock 1,2,3,4,5,6, ReleaseLockTo(4) will release
+// lock 1,2 but keep 3. ReleaseLockTo(5) will release 1,2,3 but keep 4.
+func (w *WAL) ReleaseLockTo(index uint64) error {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+
+	if len(w.locks) == 0 {
+		return nil
+	}
+
+	var smaller int
+	found := false
+	for i, l := range w.locks {
+		_, lockIndex, err := parseWALName(filepath.Base(l.Name()))
+		if err != nil {
+			return err
+		}
+		if lockIndex >= index {
+			smaller = i - 1
+			found = true
+			break
+		}
+	}
+
+	// if no lock index is greater than the release index, we can
+	// release lock up to the last one(excluding).
+	if !found {
+		smaller = len(w.locks) - 1
+	}
+
+	if smaller <= 0 {
+		return nil
+	}
+
+	for i := 0; i < smaller; i++ {
+		if w.locks[i] == nil {
+			continue
+		}
+		w.locks[i].Close()
+	}
+	w.locks = w.locks[smaller:]
+
+	return nil
+}
+
+// Close closes the current WAL file and directory.
+func (w *WAL) Close() error {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+
+	if w.fp != nil {
+		w.fp.Close()
+		w.fp = nil
+	}
+
+	if w.tail() != nil {
+		if err := w.sync(); err != nil {
+			return err
+		}
+	}
+	for _, l := range w.locks {
+		if l == nil {
+			continue
+		}
+		if err := l.Close(); err != nil {
+			w.lg.Error("failed to close WAL", zap.Error(err))
+		}
+	}
+
+	return w.dirFile.Close()
+}
+
+func (w *WAL) saveEntry(e *raftpb.Entry) error {
+	// TODO: add MustMarshalTo to reduce one allocation.
+	b := pbutil.MustMarshal(e)
+	rec := &walpb.Record{Type: EntryType, Data: b}
+	if err := w.encoder.encode(rec); err != nil {
+		return err
+	}
+	w.enti = e.Index
+	return nil
+}
+
+func (w *WAL) saveState(s *raftpb.HardState) error {
+	if raft.IsEmptyHardState(*s) {
+		return nil
+	}
+	w.state = *s
+	b := pbutil.MustMarshal(s)
+	rec := &walpb.Record{Type: StateType, Data: b}
+	return w.encoder.encode(rec)
+}
+
+func (w *WAL) Save(st raftpb.HardState, ents []raftpb.Entry) error {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+
+	// short cut, do not call sync
+	if raft.IsEmptyHardState(st) && len(ents) == 0 {
+		return nil
+	}
+
+	mustSync := raft.MustSync(st, w.state, len(ents))
+
+	// TODO(xiangli): no more reference operator
+	for i := range ents {
+		if err := w.saveEntry(&ents[i]); err != nil {
+			return err
+		}
+	}
+	if err := w.saveState(&st); err != nil {
+		return err
+	}
+
+	curOff, err := w.tail().Seek(0, io.SeekCurrent)
+	if err != nil {
+		return err
+	}
+	if curOff < SegmentSizeBytes {
+		if mustSync {
+			// gofail: var walBeforeSync struct{}
+			err = w.sync()
+			// gofail: var walAfterSync struct{}
+			return err
+		}
+		return nil
+	}
+
+	return w.cut()
+}
+
+func (w *WAL) SaveSnapshot(e walpb.Snapshot) error {
+	if err := walpb.ValidateSnapshotForWrite(&e); err != nil {
+		return err
+	}
+
+	b := pbutil.MustMarshal(&e)
+
+	w.mu.Lock()
+	defer w.mu.Unlock()
+
+	rec := &walpb.Record{Type: SnapshotType, Data: b}
+	if err := w.encoder.encode(rec); err != nil {
+		return err
+	}
+	// update enti only when snapshot is ahead of last index
+	if w.enti < e.Index {
+		w.enti = e.Index
+	}
+	return w.sync()
+}
+
+func (w *WAL) saveCrc(prevCrc uint32) error {
+	return w.encoder.encode(&walpb.Record{Type: CrcType, Crc: prevCrc})
+}
+
+func (w *WAL) tail() *fileutil.LockedFile {
+	if len(w.locks) > 0 {
+		return w.locks[len(w.locks)-1]
+	}
+	return nil
+}
+
+func (w *WAL) seq() uint64 {
+	t := w.tail()
+	if t == nil {
+		return 0
+	}
+	seq, _, err := parseWALName(filepath.Base(t.Name()))
+	if err != nil {
+		w.lg.Fatal("failed to parse WAL name", zap.String("name", t.Name()), zap.Error(err))
+	}
+	return seq
+}
+
+func closeAll(lg *zap.Logger, rcs ...io.ReadCloser) error {
+	stringArr := make([]string, 0)
+	for _, f := range rcs {
+		if err := f.Close(); err != nil {
+			lg.Warn("failed to close: ", zap.Error(err))
+			stringArr = append(stringArr, err.Error())
+		}
+	}
+	if len(stringArr) == 0 {
+		return nil
+	}
+	return errors.New(strings.Join(stringArr, ", "))
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/wal/walpb/record.go b/vendor/go.etcd.io/etcd/server/v3/storage/wal/walpb/record.go
new file mode 100644
index 0000000..30e6c06
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/wal/walpb/record.go
@@ -0,0 +1,41 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package walpb
+
+import (
+	"errors"
+	"fmt"
+)
+
+var ErrCRCMismatch = errors.New("walpb: crc mismatch")
+
+func (rec *Record) Validate(crc uint32) error {
+	if rec.Crc == crc {
+		return nil
+	}
+	return fmt.Errorf("%w: expected: %x computed: %x", ErrCRCMismatch, rec.Crc, crc)
+}
+
+// ValidateSnapshotForWrite ensures the Snapshot the newly written snapshot is valid.
+//
+// There might exist log-entries written by old etcd versions that does not conform
+// to the requirements.
+func ValidateSnapshotForWrite(e *Snapshot) error {
+	// Since etcd>=3.5.0
+	if e.ConfState == nil && e.Index > 0 {
+		return errors.New("Saved (not-initial) snapshot is missing ConfState: " + e.String())
+	}
+	return nil
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/wal/walpb/record.pb.go b/vendor/go.etcd.io/etcd/server/v3/storage/wal/walpb/record.pb.go
new file mode 100644
index 0000000..5605fbd
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/wal/walpb/record.pb.go
@@ -0,0 +1,611 @@
+// Code generated by protoc-gen-gogo. DO NOT EDIT.
+// source: record.proto
+
+package walpb
+
+import (
+	fmt "fmt"
+	io "io"
+	math "math"
+	math_bits "math/bits"
+
+	_ "github.com/gogo/protobuf/gogoproto"
+	proto "github.com/golang/protobuf/proto"
+	raftpb "go.etcd.io/raft/v3/raftpb"
+)
+
+// Reference imports to suppress errors if they are not otherwise used.
+var _ = proto.Marshal
+var _ = fmt.Errorf
+var _ = math.Inf
+
+// This is a compile-time assertion to ensure that this generated file
+// is compatible with the proto package it is being compiled against.
+// A compilation error at this line likely means your copy of the
+// proto package needs to be updated.
+const _ = proto.ProtoPackageIsVersion3 // please upgrade the proto package
+
+type Record struct {
+	Type                 int64    `protobuf:"varint,1,opt,name=type" json:"type"`
+	Crc                  uint32   `protobuf:"varint,2,opt,name=crc" json:"crc"`
+	Data                 []byte   `protobuf:"bytes,3,opt,name=data" json:"data,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
+}
+
+func (m *Record) Reset()         { *m = Record{} }
+func (m *Record) String() string { return proto.CompactTextString(m) }
+func (*Record) ProtoMessage()    {}
+func (*Record) Descriptor() ([]byte, []int) {
+	return fileDescriptor_bf94fd919e302a1d, []int{0}
+}
+func (m *Record) XXX_Unmarshal(b []byte) error {
+	return m.Unmarshal(b)
+}
+func (m *Record) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	if deterministic {
+		return xxx_messageInfo_Record.Marshal(b, m, deterministic)
+	} else {
+		b = b[:cap(b)]
+		n, err := m.MarshalToSizedBuffer(b)
+		if err != nil {
+			return nil, err
+		}
+		return b[:n], nil
+	}
+}
+func (m *Record) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_Record.Merge(m, src)
+}
+func (m *Record) XXX_Size() int {
+	return m.Size()
+}
+func (m *Record) XXX_DiscardUnknown() {
+	xxx_messageInfo_Record.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_Record proto.InternalMessageInfo
+
+// Keep in sync with raftpb.SnapshotMetadata.
+type Snapshot struct {
+	Index uint64 `protobuf:"varint,1,opt,name=index" json:"index"`
+	Term  uint64 `protobuf:"varint,2,opt,name=term" json:"term"`
+	// Field populated since >=etcd-3.5.0.
+	ConfState            *raftpb.ConfState `protobuf:"bytes,3,opt,name=conf_state,json=confState" json:"conf_state,omitempty"`
+	XXX_NoUnkeyedLiteral struct{}          `json:"-"`
+	XXX_unrecognized     []byte            `json:"-"`
+	XXX_sizecache        int32             `json:"-"`
+}
+
+func (m *Snapshot) Reset()         { *m = Snapshot{} }
+func (m *Snapshot) String() string { return proto.CompactTextString(m) }
+func (*Snapshot) ProtoMessage()    {}
+func (*Snapshot) Descriptor() ([]byte, []int) {
+	return fileDescriptor_bf94fd919e302a1d, []int{1}
+}
+func (m *Snapshot) XXX_Unmarshal(b []byte) error {
+	return m.Unmarshal(b)
+}
+func (m *Snapshot) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	if deterministic {
+		return xxx_messageInfo_Snapshot.Marshal(b, m, deterministic)
+	} else {
+		b = b[:cap(b)]
+		n, err := m.MarshalToSizedBuffer(b)
+		if err != nil {
+			return nil, err
+		}
+		return b[:n], nil
+	}
+}
+func (m *Snapshot) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_Snapshot.Merge(m, src)
+}
+func (m *Snapshot) XXX_Size() int {
+	return m.Size()
+}
+func (m *Snapshot) XXX_DiscardUnknown() {
+	xxx_messageInfo_Snapshot.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_Snapshot proto.InternalMessageInfo
+
+func init() {
+	proto.RegisterType((*Record)(nil), "walpb.Record")
+	proto.RegisterType((*Snapshot)(nil), "walpb.Snapshot")
+}
+
+func init() { proto.RegisterFile("record.proto", fileDescriptor_bf94fd919e302a1d) }
+
+var fileDescriptor_bf94fd919e302a1d = []byte{
+	// 266 bytes of a gzipped FileDescriptorProto
+	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0x3c, 0x90, 0x41, 0x4e, 0xc3, 0x30,
+	0x14, 0x44, 0x63, 0x92, 0x22, 0x30, 0x65, 0x51, 0x0b, 0xa1, 0x28, 0x8b, 0x10, 0x75, 0x15, 0x09,
+	0x29, 0x46, 0x70, 0x02, 0xca, 0x9e, 0x45, 0xba, 0x63, 0x83, 0x5c, 0xe7, 0x27, 0x54, 0x6a, 0xf3,
+	0xad, 0x1f, 0xab, 0x85, 0x9b, 0x70, 0xa4, 0x2c, 0x39, 0x01, 0x82, 0x70, 0x11, 0x64, 0xa7, 0xb0,
+	0xfa, 0xa3, 0x37, 0x9a, 0x19, 0xcb, 0x7c, 0x4a, 0xa0, 0x91, 0xaa, 0xc2, 0x10, 0x5a, 0x14, 0x93,
+	0xbd, 0xda, 0x98, 0x55, 0x72, 0xd1, 0x60, 0x83, 0x9e, 0x48, 0xa7, 0x46, 0x33, 0x99, 0x91, 0xaa,
+	0xad, 0x59, 0x49, 0x77, 0x46, 0x34, 0x7f, 0xe4, 0xc7, 0xa5, 0xcf, 0x8b, 0x98, 0x47, 0xf6, 0xcd,
+	0x40, 0xcc, 0x32, 0x96, 0x87, 0x8b, 0xa8, 0xff, 0xbc, 0x0a, 0x4a, 0x4f, 0xc4, 0x25, 0x0f, 0x35,
+	0xe9, 0xf8, 0x28, 0x63, 0xf9, 0xf9, 0xc1, 0x70, 0x40, 0x08, 0x1e, 0x55, 0xca, 0xaa, 0x38, 0xcc,
+	0x58, 0x3e, 0x2d, 0xbd, 0x9e, 0x13, 0x3f, 0x59, 0xb6, 0xca, 0x74, 0x2f, 0x68, 0x45, 0xc2, 0x27,
+	0xeb, 0xb6, 0x82, 0x57, 0x5f, 0x19, 0x1d, 0x92, 0x23, 0xf2, 0x6b, 0x40, 0x5b, 0x5f, 0x1a, 0xfd,
+	0xaf, 0x01, 0x6d, 0xc5, 0x0d, 0xe7, 0x1a, 0xdb, 0xfa, 0xb9, 0xb3, 0xca, 0x82, 0xef, 0x3e, 0xbb,
+	0x9d, 0x15, 0xe3, 0xcb, 0x8b, 0x07, 0x6c, 0xeb, 0xa5, 0x33, 0xca, 0x53, 0xfd, 0x27, 0x17, 0xf7,
+	0xfd, 0x77, 0x1a, 0xf4, 0x43, 0xca, 0x3e, 0x86, 0x94, 0x7d, 0x0d, 0x29, 0x7b, 0xff, 0x49, 0x83,
+	0xa7, 0xeb, 0x06, 0x0b, 0xb0, 0xba, 0x2a, 0xd6, 0x28, 0xdd, 0x95, 0x1d, 0xd0, 0x0e, 0x48, 0xee,
+	0xee, 0x64, 0x67, 0x91, 0x54, 0x03, 0x72, 0xaf, 0x36, 0xd2, 0xff, 0xd7, 0x6f, 0x00, 0x00, 0x00,
+	0xff, 0xff, 0xcf, 0xa9, 0xf0, 0x02, 0x45, 0x01, 0x00, 0x00,
+}
+
+func (m *Record) Marshal() (dAtA []byte, err error) {
+	size := m.Size()
+	dAtA = make([]byte, size)
+	n, err := m.MarshalToSizedBuffer(dAtA[:size])
+	if err != nil {
+		return nil, err
+	}
+	return dAtA[:n], nil
+}
+
+func (m *Record) MarshalTo(dAtA []byte) (int, error) {
+	size := m.Size()
+	return m.MarshalToSizedBuffer(dAtA[:size])
+}
+
+func (m *Record) MarshalToSizedBuffer(dAtA []byte) (int, error) {
+	i := len(dAtA)
+	_ = i
+	var l int
+	_ = l
+	if m.XXX_unrecognized != nil {
+		i -= len(m.XXX_unrecognized)
+		copy(dAtA[i:], m.XXX_unrecognized)
+	}
+	if m.Data != nil {
+		i -= len(m.Data)
+		copy(dAtA[i:], m.Data)
+		i = encodeVarintRecord(dAtA, i, uint64(len(m.Data)))
+		i--
+		dAtA[i] = 0x1a
+	}
+	i = encodeVarintRecord(dAtA, i, uint64(m.Crc))
+	i--
+	dAtA[i] = 0x10
+	i = encodeVarintRecord(dAtA, i, uint64(m.Type))
+	i--
+	dAtA[i] = 0x8
+	return len(dAtA) - i, nil
+}
+
+func (m *Snapshot) Marshal() (dAtA []byte, err error) {
+	size := m.Size()
+	dAtA = make([]byte, size)
+	n, err := m.MarshalToSizedBuffer(dAtA[:size])
+	if err != nil {
+		return nil, err
+	}
+	return dAtA[:n], nil
+}
+
+func (m *Snapshot) MarshalTo(dAtA []byte) (int, error) {
+	size := m.Size()
+	return m.MarshalToSizedBuffer(dAtA[:size])
+}
+
+func (m *Snapshot) MarshalToSizedBuffer(dAtA []byte) (int, error) {
+	i := len(dAtA)
+	_ = i
+	var l int
+	_ = l
+	if m.XXX_unrecognized != nil {
+		i -= len(m.XXX_unrecognized)
+		copy(dAtA[i:], m.XXX_unrecognized)
+	}
+	if m.ConfState != nil {
+		{
+			size, err := m.ConfState.MarshalToSizedBuffer(dAtA[:i])
+			if err != nil {
+				return 0, err
+			}
+			i -= size
+			i = encodeVarintRecord(dAtA, i, uint64(size))
+		}
+		i--
+		dAtA[i] = 0x1a
+	}
+	i = encodeVarintRecord(dAtA, i, uint64(m.Term))
+	i--
+	dAtA[i] = 0x10
+	i = encodeVarintRecord(dAtA, i, uint64(m.Index))
+	i--
+	dAtA[i] = 0x8
+	return len(dAtA) - i, nil
+}
+
+func encodeVarintRecord(dAtA []byte, offset int, v uint64) int {
+	offset -= sovRecord(v)
+	base := offset
+	for v >= 1<<7 {
+		dAtA[offset] = uint8(v&0x7f | 0x80)
+		v >>= 7
+		offset++
+	}
+	dAtA[offset] = uint8(v)
+	return base
+}
+func (m *Record) Size() (n int) {
+	if m == nil {
+		return 0
+	}
+	var l int
+	_ = l
+	n += 1 + sovRecord(uint64(m.Type))
+	n += 1 + sovRecord(uint64(m.Crc))
+	if m.Data != nil {
+		l = len(m.Data)
+		n += 1 + l + sovRecord(uint64(l))
+	}
+	if m.XXX_unrecognized != nil {
+		n += len(m.XXX_unrecognized)
+	}
+	return n
+}
+
+func (m *Snapshot) Size() (n int) {
+	if m == nil {
+		return 0
+	}
+	var l int
+	_ = l
+	n += 1 + sovRecord(uint64(m.Index))
+	n += 1 + sovRecord(uint64(m.Term))
+	if m.ConfState != nil {
+		l = m.ConfState.Size()
+		n += 1 + l + sovRecord(uint64(l))
+	}
+	if m.XXX_unrecognized != nil {
+		n += len(m.XXX_unrecognized)
+	}
+	return n
+}
+
+func sovRecord(x uint64) (n int) {
+	return (math_bits.Len64(x|1) + 6) / 7
+}
+func sozRecord(x uint64) (n int) {
+	return sovRecord(uint64((x << 1) ^ uint64((int64(x) >> 63))))
+}
+func (m *Record) Unmarshal(dAtA []byte) error {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		preIndex := iNdEx
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return ErrIntOverflowRecord
+			}
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= uint64(b&0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		if wireType == 4 {
+			return fmt.Errorf("proto: Record: wiretype end group for non-group")
+		}
+		if fieldNum <= 0 {
+			return fmt.Errorf("proto: Record: illegal tag %d (wire type %d)", fieldNum, wire)
+		}
+		switch fieldNum {
+		case 1:
+			if wireType != 0 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Type", wireType)
+			}
+			m.Type = 0
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowRecord
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				m.Type |= int64(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+		case 2:
+			if wireType != 0 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Crc", wireType)
+			}
+			m.Crc = 0
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowRecord
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				m.Crc |= uint32(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+		case 3:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Data", wireType)
+			}
+			var byteLen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowRecord
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				byteLen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if byteLen < 0 {
+				return ErrInvalidLengthRecord
+			}
+			postIndex := iNdEx + byteLen
+			if postIndex < 0 {
+				return ErrInvalidLengthRecord
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.Data = append(m.Data[:0], dAtA[iNdEx:postIndex]...)
+			if m.Data == nil {
+				m.Data = []byte{}
+			}
+			iNdEx = postIndex
+		default:
+			iNdEx = preIndex
+			skippy, err := skipRecord(dAtA[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
+				return ErrInvalidLengthRecord
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.XXX_unrecognized = append(m.XXX_unrecognized, dAtA[iNdEx:iNdEx+skippy]...)
+			iNdEx += skippy
+		}
+	}
+
+	if iNdEx > l {
+		return io.ErrUnexpectedEOF
+	}
+	return nil
+}
+func (m *Snapshot) Unmarshal(dAtA []byte) error {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		preIndex := iNdEx
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return ErrIntOverflowRecord
+			}
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= uint64(b&0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		if wireType == 4 {
+			return fmt.Errorf("proto: Snapshot: wiretype end group for non-group")
+		}
+		if fieldNum <= 0 {
+			return fmt.Errorf("proto: Snapshot: illegal tag %d (wire type %d)", fieldNum, wire)
+		}
+		switch fieldNum {
+		case 1:
+			if wireType != 0 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Index", wireType)
+			}
+			m.Index = 0
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowRecord
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				m.Index |= uint64(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+		case 2:
+			if wireType != 0 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Term", wireType)
+			}
+			m.Term = 0
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowRecord
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				m.Term |= uint64(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+		case 3:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field ConfState", wireType)
+			}
+			var msglen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowRecord
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				msglen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if msglen < 0 {
+				return ErrInvalidLengthRecord
+			}
+			postIndex := iNdEx + msglen
+			if postIndex < 0 {
+				return ErrInvalidLengthRecord
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			if m.ConfState == nil {
+				m.ConfState = &raftpb.ConfState{}
+			}
+			if err := m.ConfState.Unmarshal(dAtA[iNdEx:postIndex]); err != nil {
+				return err
+			}
+			iNdEx = postIndex
+		default:
+			iNdEx = preIndex
+			skippy, err := skipRecord(dAtA[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
+				return ErrInvalidLengthRecord
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.XXX_unrecognized = append(m.XXX_unrecognized, dAtA[iNdEx:iNdEx+skippy]...)
+			iNdEx += skippy
+		}
+	}
+
+	if iNdEx > l {
+		return io.ErrUnexpectedEOF
+	}
+	return nil
+}
+func skipRecord(dAtA []byte) (n int, err error) {
+	l := len(dAtA)
+	iNdEx := 0
+	depth := 0
+	for iNdEx < l {
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return 0, ErrIntOverflowRecord
+			}
+			if iNdEx >= l {
+				return 0, io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= (uint64(b) & 0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		wireType := int(wire & 0x7)
+		switch wireType {
+		case 0:
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return 0, ErrIntOverflowRecord
+				}
+				if iNdEx >= l {
+					return 0, io.ErrUnexpectedEOF
+				}
+				iNdEx++
+				if dAtA[iNdEx-1] < 0x80 {
+					break
+				}
+			}
+		case 1:
+			iNdEx += 8
+		case 2:
+			var length int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return 0, ErrIntOverflowRecord
+				}
+				if iNdEx >= l {
+					return 0, io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				length |= (int(b) & 0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if length < 0 {
+				return 0, ErrInvalidLengthRecord
+			}
+			iNdEx += length
+		case 3:
+			depth++
+		case 4:
+			if depth == 0 {
+				return 0, ErrUnexpectedEndOfGroupRecord
+			}
+			depth--
+		case 5:
+			iNdEx += 4
+		default:
+			return 0, fmt.Errorf("proto: illegal wireType %d", wireType)
+		}
+		if iNdEx < 0 {
+			return 0, ErrInvalidLengthRecord
+		}
+		if depth == 0 {
+			return iNdEx, nil
+		}
+	}
+	return 0, io.ErrUnexpectedEOF
+}
+
+var (
+	ErrInvalidLengthRecord        = fmt.Errorf("proto: negative length found during unmarshaling")
+	ErrIntOverflowRecord          = fmt.Errorf("proto: integer overflow")
+	ErrUnexpectedEndOfGroupRecord = fmt.Errorf("proto: unexpected end of group")
+)
diff --git a/vendor/go.etcd.io/etcd/server/v3/storage/wal/walpb/record.proto b/vendor/go.etcd.io/etcd/server/v3/storage/wal/walpb/record.proto
new file mode 100644
index 0000000..e1050fd
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/storage/wal/walpb/record.proto
@@ -0,0 +1,26 @@
+syntax = "proto2";
+package walpb;
+
+import "gogoproto/gogo.proto";
+import "raftpb/raft.proto";
+
+option go_package = "go.etcd.io/etcd/server/v3/storage/wal/walpb";
+
+option (gogoproto.marshaler_all) = true;
+option (gogoproto.sizer_all) = true;
+option (gogoproto.unmarshaler_all) = true;
+option (gogoproto.goproto_getters_all) = false;
+
+message Record {
+	optional int64 type  = 1 [(gogoproto.nullable) = false];
+	optional uint32 crc  = 2 [(gogoproto.nullable) = false];
+	optional bytes data  = 3;
+}
+
+// Keep in sync with raftpb.SnapshotMetadata.
+message Snapshot {
+	optional uint64 index = 1 [(gogoproto.nullable) = false];
+	optional uint64 term  = 2 [(gogoproto.nullable) = false];
+	// Field populated since >=etcd-3.5.0.
+	optional raftpb.ConfState conf_state = 3;
+}
diff --git a/vendor/go.etcd.io/etcd/server/v3/verify/doc.go b/vendor/go.etcd.io/etcd/server/v3/verify/doc.go
new file mode 100644
index 0000000..2c42bf6
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/verify/doc.go
@@ -0,0 +1,20 @@
+// Copyright 2021 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package verify
+
+// verify package is analyzing persistent state of etcd to find potential
+// inconsistencies.
+// In particular it covers cross-checking between different aspacts of etcd
+// storage like WAL & Backend.
diff --git a/vendor/go.etcd.io/etcd/server/v3/verify/verify.go b/vendor/go.etcd.io/etcd/server/v3/verify/verify.go
new file mode 100644
index 0000000..0dc99af
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/server/v3/verify/verify.go
@@ -0,0 +1,148 @@
+// Copyright 2021 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package verify
+
+import (
+	"fmt"
+
+	"go.uber.org/zap"
+
+	"go.etcd.io/etcd/client/pkg/v3/fileutil"
+	"go.etcd.io/etcd/client/pkg/v3/verify"
+	"go.etcd.io/etcd/server/v3/storage/backend"
+	"go.etcd.io/etcd/server/v3/storage/datadir"
+	"go.etcd.io/etcd/server/v3/storage/schema"
+	wal2 "go.etcd.io/etcd/server/v3/storage/wal"
+	"go.etcd.io/etcd/server/v3/storage/wal/walpb"
+	"go.etcd.io/raft/v3/raftpb"
+)
+
+const envVerifyValueStorageWAL verify.VerificationType = "storage_wal"
+
+type Config struct {
+	// DataDir is a root directory where the data being verified are stored.
+	DataDir string
+
+	// ExactIndex requires consistent_index in backend exactly match the last committed WAL entry.
+	// Usually backend's consistent_index needs to be <= WAL.commit, but for backups the match
+	// is expected to be exact.
+	ExactIndex bool
+
+	Logger *zap.Logger
+}
+
+// Verify performs consistency checks of given etcd data-directory.
+// The errors are reported as the returned error, but for some situations
+// the function can also panic.
+// The function is expected to work on not-in-use data model, i.e.
+// no file-locks should be taken. Verify does not modified the data.
+func Verify(cfg Config) (retErr error) {
+	lg := cfg.Logger
+	if lg == nil {
+		lg = zap.NewNop()
+	}
+
+	if !fileutil.Exist(datadir.ToBackendFileName(cfg.DataDir)) {
+		lg.Info("verification skipped due to non exist db file")
+		return nil
+	}
+
+	lg.Info("verification of persisted state", zap.String("data-dir", cfg.DataDir))
+	defer func() {
+		if retErr != nil {
+			lg.Error("verification of persisted state failed",
+				zap.String("data-dir", cfg.DataDir),
+				zap.Error(retErr))
+		} else if r := recover(); r != nil {
+			lg.Error("verification of persisted state failed",
+				zap.String("data-dir", cfg.DataDir))
+			panic(r)
+		} else {
+			lg.Info("verification of persisted state successful", zap.String("data-dir", cfg.DataDir))
+		}
+	}()
+
+	be := backend.NewDefaultBackend(lg, datadir.ToBackendFileName(cfg.DataDir))
+	defer be.Close()
+
+	snapshot, hardstate, err := validateWAL(cfg)
+	if err != nil {
+		return err
+	}
+
+	// TODO: Perform validation of consistency of membership between
+	// backend/members & WAL confstate (and maybe storev2 if still exists).
+
+	return validateConsistentIndex(cfg, hardstate, snapshot, be)
+}
+
+// VerifyIfEnabled performs verification according to ETCD_VERIFY env settings.
+// See Verify for more information.
+func VerifyIfEnabled(cfg Config) error {
+	if verify.IsVerificationEnabled(envVerifyValueStorageWAL) {
+		return Verify(cfg)
+	}
+	return nil
+}
+
+// MustVerifyIfEnabled performs verification according to ETCD_VERIFY env settings
+// and exits in case of found problems.
+// See Verify for more information.
+func MustVerifyIfEnabled(cfg Config) {
+	if err := VerifyIfEnabled(cfg); err != nil {
+		cfg.Logger.Fatal("Verification failed",
+			zap.String("data-dir", cfg.DataDir),
+			zap.Error(err))
+	}
+}
+
+func validateConsistentIndex(cfg Config, hardstate *raftpb.HardState, snapshot *walpb.Snapshot, be backend.Backend) error {
+	index, term := schema.ReadConsistentIndex(be.ReadTx())
+	if cfg.ExactIndex && index != hardstate.Commit {
+		return fmt.Errorf("backend.ConsistentIndex (%v) expected == WAL.HardState.commit (%v)", index, hardstate.Commit)
+	}
+	if cfg.ExactIndex && term != hardstate.Term {
+		return fmt.Errorf("backend.Term (%v) expected == WAL.HardState.term, (%v)", term, hardstate.Term)
+	}
+	if index > hardstate.Commit {
+		return fmt.Errorf("backend.ConsistentIndex (%v) must be <= WAL.HardState.commit (%v)", index, hardstate.Commit)
+	}
+	if term > hardstate.Term {
+		return fmt.Errorf("backend.Term (%v) must be <= WAL.HardState.term, (%v)", term, hardstate.Term)
+	}
+
+	if index < snapshot.Index {
+		return fmt.Errorf("backend.ConsistentIndex (%v) must be >= last snapshot index (%v)", index, snapshot.Index)
+	}
+
+	cfg.Logger.Info("verification: consistentIndex OK", zap.Uint64("backend-consistent-index", index), zap.Uint64("hardstate-commit", hardstate.Commit))
+	return nil
+}
+
+func validateWAL(cfg Config) (*walpb.Snapshot, *raftpb.HardState, error) {
+	walDir := datadir.ToWALDir(cfg.DataDir)
+
+	walSnaps, err := wal2.ValidSnapshotEntries(cfg.Logger, walDir)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	snapshot := walSnaps[len(walSnaps)-1]
+	hardstate, err := wal2.Verify(cfg.Logger, walDir, snapshot)
+	if err != nil {
+		return nil, nil, err
+	}
+	return &snapshot, hardstate, nil
+}