Applying consistency fix: ClusterVersionSet (and co) might get no applied on v2store

ClusterVersionSet, ClusterMemberAttrSet, DowngradeInfoSet functions are
writing both to V2store and backend. Prior this CL there were
in a branch not executed if shouldApplyV3 was false,
e.g. during restore when Backend is up-to-date (has high
consistency-index) while v2store requires replay from WAL log.

The most serious consequence of this bug was that v2store after restore
could have different index (revision) than the same exact store before restore,
so potentially different content between replicas.

Also this change is supressing double-applying of Membership
(ClusterConfig) changes on Backend (store v3) - that lackilly are not
part of MVCC/KeyValue store, so they didn't caused Revisions to be
bumped.

Inspired by jingyih@ comment:
https://github.com/etcd-io/etcd/pull/12820#issuecomment-815299406

etcdctl/ctlv3/command/migrate_command.go

@@ -208,15 +208,15 @@ func applyConf(cc raftpb.ConfChange, cl *membership.RaftCluster) {
 		if err := json.Unmarshal(cc.Context, m); err != nil {
 			panic(err)
 		}
-		cl.AddMember(m)
+		cl.AddMember(m, true)
 	case raftpb.ConfChangeRemoveNode:
-		cl.RemoveMember(types.ID(cc.NodeID))
+		cl.RemoveMember(types.ID(cc.NodeID), true)
 	case raftpb.ConfChangeUpdateNode:
 		m := new(membership.Member)
 		if err := json.Unmarshal(cc.Context, m); err != nil {
 			panic(err)
 		}
-		cl.UpdateRaftAttributes(m.ID, m.RaftAttributes)
+		cl.UpdateRaftAttributes(m.ID, m.RaftAttributes, true)
 	}
 }
 

etcdctl/snapshot/v3_snapshot.go

@@ -398,7 +398,7 @@ func (s *v3Manager) saveWALAndSnap() error {
 	st := v2store.New(etcdserver.StoreClusterPrefix, etcdserver.StoreKeysPrefix)
 	s.cl.SetStore(st)
 	for _, m := range s.cl.Members() {
-		s.cl.AddMember(m)
+		s.cl.AddMember(m, true)
 	}
 
 	m := s.cl.MemberByName(s.name)

server/etcdserver/api/membership/cluster.go

@@ -285,6 +285,7 @@ func (c *RaftCluster) Recover(onSet func(*zap.Logger, *semver.Version)) {
 // ValidateConfigurationChange takes a proposed ConfChange and
 // ensures that it is still valid.
 func (c *RaftCluster) ValidateConfigurationChange(cc raftpb.ConfChange) error {
+	// TODO: this must be switched to backend as well.
 	members, removed := membersFromStore(c.lg, c.v2store)
 	id := types.ID(cc.NodeID)
 	if removed[id] {
@@ -370,13 +371,13 @@ func (c *RaftCluster) ValidateConfigurationChange(cc raftpb.ConfChange) error {
 // 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) {
+func (c *RaftCluster) AddMember(m *Member, shouldApplyV3 bool) {
 	c.Lock()
 	defer c.Unlock()
 	if c.v2store != nil {
 		mustSaveMemberToStore(c.lg, c.v2store, m)
 	}
-	if c.be != nil {
+	if c.be != nil && shouldApplyV3 {
 		mustSaveMemberToBackend(c.lg, c.be, m)
 	}
 
@@ -393,13 +394,13 @@ func (c *RaftCluster) AddMember(m *Member) {
 
 // RemoveMember removes a member from the store.
 // The given id MUST exist, or the function panics.
-func (c *RaftCluster) RemoveMember(id types.ID) {
+func (c *RaftCluster) RemoveMember(id types.ID, shouldApplyV3 bool) {
 	c.Lock()
 	defer c.Unlock()
 	if c.v2store != nil {
 		mustDeleteMemberFromStore(c.lg, c.v2store, id)
 	}
-	if c.be != nil {
+	if c.be != nil && shouldApplyV3 {
 		mustDeleteMemberFromBackend(c.be, id)
 	}
 
@@ -425,7 +426,7 @@ func (c *RaftCluster) RemoveMember(id types.ID) {
 	}
 }
 
-func (c *RaftCluster) UpdateAttributes(id types.ID, attr Attributes) {
+func (c *RaftCluster) UpdateAttributes(id types.ID, attr Attributes, shouldApplyV3 bool) {
 	c.Lock()
 	defer c.Unlock()
 
@@ -434,7 +435,7 @@ func (c *RaftCluster) UpdateAttributes(id types.ID, attr Attributes) {
 		if c.v2store != nil {
 			mustUpdateMemberAttrInStore(c.lg, c.v2store, m)
 		}
-		if c.be != nil {
+		if c.be != nil && shouldApplyV3 {
 			mustSaveMemberToBackend(c.lg, c.be, m)
 		}
 		return
@@ -459,7 +460,7 @@ func (c *RaftCluster) UpdateAttributes(id types.ID, attr Attributes) {
 }
 
 // PromoteMember marks the member's IsLearner RaftAttributes to false.
-func (c *RaftCluster) PromoteMember(id types.ID) {
+func (c *RaftCluster) PromoteMember(id types.ID, shouldApplyV3 bool) {
 	c.Lock()
 	defer c.Unlock()
 
@@ -467,7 +468,7 @@ func (c *RaftCluster) PromoteMember(id types.ID) {
 	if c.v2store != nil {
 		mustUpdateMemberInStore(c.lg, c.v2store, c.members[id])
 	}
-	if c.be != nil {
+	if c.be != nil && shouldApplyV3 {
 		mustSaveMemberToBackend(c.lg, c.be, c.members[id])
 	}
 
@@ -478,7 +479,7 @@ func (c *RaftCluster) PromoteMember(id types.ID) {
 	)
 }
 
-func (c *RaftCluster) UpdateRaftAttributes(id types.ID, raftAttr RaftAttributes) {
+func (c *RaftCluster) UpdateRaftAttributes(id types.ID, raftAttr RaftAttributes, shouldApplyV3 bool) {
 	c.Lock()
 	defer c.Unlock()
 
@@ -486,7 +487,7 @@ func (c *RaftCluster) UpdateRaftAttributes(id types.ID, raftAttr RaftAttributes)
 	if c.v2store != nil {
 		mustUpdateMemberInStore(c.lg, c.v2store, c.members[id])
 	}
-	if c.be != nil {
+	if c.be != nil && shouldApplyV3 {
 		mustSaveMemberToBackend(c.lg, c.be, c.members[id])
 	}
 
@@ -508,7 +509,7 @@ func (c *RaftCluster) Version() *semver.Version {
 	return semver.Must(semver.NewVersion(c.version.String()))
 }
 
-func (c *RaftCluster) SetVersion(ver *semver.Version, onSet func(*zap.Logger, *semver.Version)) {
+func (c *RaftCluster) SetVersion(ver *semver.Version, onSet func(*zap.Logger, *semver.Version), shouldApplyV3 bool) {
 	c.Lock()
 	defer c.Unlock()
 	if c.version != nil {
@@ -533,7 +534,7 @@ func (c *RaftCluster) SetVersion(ver *semver.Version, onSet func(*zap.Logger, *s
 	if c.v2store != nil {
 		mustSaveClusterVersionToStore(c.lg, c.v2store, ver)
 	}
-	if c.be != nil {
+	if c.be != nil && shouldApplyV3 {
 		mustSaveClusterVersionToBackend(c.be, ver)
 	}
 	if oldVer != nil {
@@ -809,11 +810,11 @@ func (c *RaftCluster) DowngradeInfo() *DowngradeInfo {
 	return d
 }
 
-func (c *RaftCluster) SetDowngradeInfo(d *DowngradeInfo) {
+func (c *RaftCluster) SetDowngradeInfo(d *DowngradeInfo, shouldApplyV3 bool) {
 	c.Lock()
 	defer c.Unlock()
 
-	if c.be != nil {
+	if c.be != nil && shouldApplyV3 {
 		mustSaveDowngradeToBackend(c.lg, c.be, d)
 	}
 

server/etcdserver/api/membership/cluster_test.go

@@ -283,9 +283,9 @@ func TestClusterValidateConfigurationChange(t *testing.T) {
 	cl.SetStore(v2store.New())
 	for i := 1; i <= 4; i++ {
 		attr := RaftAttributes{PeerURLs: []string{fmt.Sprintf("http://127.0.0.1:%d", i)}}
-		cl.AddMember(&Member{ID: types.ID(i), RaftAttributes: attr})
+		cl.AddMember(&Member{ID: types.ID(i), RaftAttributes: attr}, true)
 	}
-	cl.RemoveMember(4)
+	cl.RemoveMember(4, true)
 
 	attr := RaftAttributes{PeerURLs: []string{fmt.Sprintf("http://127.0.0.1:%d", 1)}}
 	ctx, err := json.Marshal(&Member{ID: types.ID(5), RaftAttributes: attr})
@@ -446,7 +446,7 @@ func TestClusterGenID(t *testing.T) {
 	previd := cs.ID()
 
 	cs.SetStore(mockstore.NewNop())
-	cs.AddMember(newTestMember(3, nil, "", nil))
+	cs.AddMember(newTestMember(3, nil, "", nil), true)
 	cs.genID()
 	if cs.ID() == previd {
 		t.Fatalf("cluster.ID = %v, want not %v", cs.ID(), previd)
@@ -489,7 +489,7 @@ func TestClusterAddMember(t *testing.T) {
 	st := mockstore.NewRecorder()
 	c := newTestCluster(t, nil)
 	c.SetStore(st)
-	c.AddMember(newTestMember(1, nil, "node1", nil))
+	c.AddMember(newTestMember(1, nil, "node1", nil), true)
 
 	wactions := []testutil.Action{
 		{
@@ -512,7 +512,7 @@ func TestClusterAddMemberAsLearner(t *testing.T) {
 	st := mockstore.NewRecorder()
 	c := newTestCluster(t, nil)
 	c.SetStore(st)
-	c.AddMember(newTestMemberAsLearner(1, nil, "node1", nil))
+	c.AddMember(newTestMemberAsLearner(1, nil, "node1", nil), true)
 
 	wactions := []testutil.Action{
 		{
@@ -555,7 +555,7 @@ func TestClusterRemoveMember(t *testing.T) {
 	st := mockstore.NewRecorder()
 	c := newTestCluster(t, nil)
 	c.SetStore(st)
-	c.RemoveMember(1)
+	c.RemoveMember(1, true)
 
 	wactions := []testutil.Action{
 		{Name: "Delete", Params: []interface{}{MemberStoreKey(1), true, true}},
@@ -595,7 +595,7 @@ func TestClusterUpdateAttributes(t *testing.T) {
 		c := newTestCluster(t, tt.mems)
 		c.removed = tt.removed
 
-		c.UpdateAttributes(types.ID(1), Attributes{Name: name, ClientURLs: clientURLs})
+		c.UpdateAttributes(types.ID(1), Attributes{Name: name, ClientURLs: clientURLs}, true)
 		if g := c.Members(); !reflect.DeepEqual(g, tt.wmems) {
 			t.Errorf("#%d: members = %+v, want %+v", i, g, tt.wmems)
 		}

server/etcdserver/apply.go

@@ -54,14 +54,14 @@ type applyResult struct {
 
 // applierV3Internal is the interface for processing internal V3 raft request
 type applierV3Internal interface {
-	ClusterVersionSet(r *membershippb.ClusterVersionSetRequest)
+	ClusterVersionSet(r *membershippb.ClusterVersionSetRequest, shouldApplyV3 bool)
-	ClusterMemberAttrSet(r *membershippb.ClusterMemberAttrSetRequest)
+	ClusterMemberAttrSet(r *membershippb.ClusterMemberAttrSetRequest, shouldApplyV3 bool)
-	DowngradeInfoSet(r *membershippb.DowngradeInfoSetRequest)
+	DowngradeInfoSet(r *membershippb.DowngradeInfoSetRequest, shouldApplyV3 bool)
 }
 
 // applierV3 is the interface for processing V3 raft messages
 type applierV3 interface {
-	Apply(r *pb.InternalRaftRequest) *applyResult
+	Apply(r *pb.InternalRaftRequest, shouldApplyV3 bool) *applyResult
 
 	Put(ctx context.Context, txn mvcc.TxnWrite, p *pb.PutRequest) (*pb.PutResponse, *traceutil.Trace, error)
 	Range(ctx context.Context, txn mvcc.TxnRead, r *pb.RangeRequest) (*pb.RangeResponse, error)
@@ -130,7 +130,7 @@ func (s *EtcdServer) newApplierV3() applierV3 {
 	)
 }
 
-func (a *applierV3backend) Apply(r *pb.InternalRaftRequest) *applyResult {
+func (a *applierV3backend) Apply(r *pb.InternalRaftRequest, shouldApplyV3 bool) *applyResult {
 	op := "unknown"
 	ar := &applyResult{}
 	defer func(start time.Time) {
@@ -142,6 +142,25 @@ func (a *applierV3backend) Apply(r *pb.InternalRaftRequest) *applyResult {
 		}
 	}(time.Now())
 
+	switch {
+	case r.ClusterVersionSet != nil: // Implemented in 3.5.x
+		op = "ClusterVersionSet"
+		a.s.applyV3Internal.ClusterVersionSet(r.ClusterVersionSet, shouldApplyV3)
+		return nil
+	case r.ClusterMemberAttrSet != nil:
+		op = "ClusterMemberAttrSet" // Implemented in 3.5.x
+		a.s.applyV3Internal.ClusterMemberAttrSet(r.ClusterMemberAttrSet, shouldApplyV3)
+		return nil
+	case r.DowngradeInfoSet != nil:
+		op = "DowngradeInfoSet" // Implemented in 3.5.x
+		a.s.applyV3Internal.DowngradeInfoSet(r.DowngradeInfoSet, shouldApplyV3)
+		return nil
+	}
+
+	if !shouldApplyV3 {
+		return nil
+	}
+
 	// call into a.s.applyV3.F instead of a.F so upper appliers can check individual calls
 	switch {
 	case r.Range != nil:
@@ -221,15 +240,6 @@ func (a *applierV3backend) Apply(r *pb.InternalRaftRequest) *applyResult {
 	case r.AuthRoleList != nil:
 		op = "AuthRoleList"
 		ar.resp, ar.err = a.s.applyV3.RoleList(r.AuthRoleList)
-	case r.ClusterVersionSet != nil: // Implemented in 3.5.x
-		op = "ClusterVersionSet"
-		a.s.applyV3Internal.ClusterVersionSet(r.ClusterVersionSet)
-	case r.ClusterMemberAttrSet != nil:
-		op = "ClusterMemberAttrSet" // Implemented in 3.5.x
-		a.s.applyV3Internal.ClusterMemberAttrSet(r.ClusterMemberAttrSet)
-	case r.DowngradeInfoSet != nil:
-		op = "DowngradeInfoSet" // Implemented in 3.5.x
-		a.s.applyV3Internal.DowngradeInfoSet(r.DowngradeInfoSet)
 	default:
 		a.s.lg.Panic("not implemented apply", zap.Stringer("raft-request", r))
 	}
@@ -903,26 +913,27 @@ func (a *applierV3backend) RoleList(r *pb.AuthRoleListRequest) (*pb.AuthRoleList
 	return resp, err
 }
 
-func (a *applierV3backend) ClusterVersionSet(r *membershippb.ClusterVersionSetRequest) {
+func (a *applierV3backend) ClusterVersionSet(r *membershippb.ClusterVersionSetRequest, shouldApplyV3 bool) {
-	a.s.cluster.SetVersion(semver.Must(semver.NewVersion(r.Ver)), api.UpdateCapability)
+	a.s.cluster.SetVersion(semver.Must(semver.NewVersion(r.Ver)), api.UpdateCapability, shouldApplyV3)
 }
 
-func (a *applierV3backend) ClusterMemberAttrSet(r *membershippb.ClusterMemberAttrSetRequest) {
+func (a *applierV3backend) ClusterMemberAttrSet(r *membershippb.ClusterMemberAttrSetRequest, shouldApplyV3 bool) {
 	a.s.cluster.UpdateAttributes(
 		types.ID(r.Member_ID),
 		membership.Attributes{
 			Name:       r.MemberAttributes.Name,
 			ClientURLs: r.MemberAttributes.ClientUrls,
 		},
+		shouldApplyV3,
 	)
 }
 
-func (a *applierV3backend) DowngradeInfoSet(r *membershippb.DowngradeInfoSetRequest) {
+func (a *applierV3backend) DowngradeInfoSet(r *membershippb.DowngradeInfoSetRequest, shouldApplyV3 bool) {
 	d := membership.DowngradeInfo{Enabled: false}
 	if r.Enabled {
 		d = membership.DowngradeInfo{Enabled: true, TargetVersion: r.Ver}
 	}
-	a.s.cluster.SetDowngradeInfo(&d)
+	a.s.cluster.SetDowngradeInfo(&d, shouldApplyV3)
 }
 
 type quotaApplierV3 struct {

server/etcdserver/apply_auth.go

@@ -41,7 +41,7 @@ func newAuthApplierV3(as auth.AuthStore, base applierV3, lessor lease.Lessor) *a
 	return &authApplierV3{applierV3: base, as: as, lessor: lessor}
 }
 
-func (aa *authApplierV3) Apply(r *pb.InternalRaftRequest) *applyResult {
+func (aa *authApplierV3) Apply(r *pb.InternalRaftRequest, shouldApplyV3 bool) *applyResult {
 	aa.mu.Lock()
 	defer aa.mu.Unlock()
 	if r.Header != nil {
@@ -57,7 +57,7 @@ func (aa *authApplierV3) Apply(r *pb.InternalRaftRequest) *applyResult {
 			return &applyResult{err: err}
 		}
 	}
-	ret := aa.applierV3.Apply(r)
+	ret := aa.applierV3.Apply(r, shouldApplyV3)
 	aa.authInfo.Username = ""
 	aa.authInfo.Revision = 0
 	return ret

server/etcdserver/apply_v2.go

@@ -87,7 +87,7 @@ func (a *applierV2store) Put(r *RequestV2) Response {
 				a.lg.Panic("failed to unmarshal", zap.String("value", r.Val), zap.Error(err))
 			}
 			if a.cluster != nil {
-				a.cluster.UpdateAttributes(id, attr)
+				a.cluster.UpdateAttributes(id, attr, true)
 			}
 			// return an empty response since there is no consumer.
 			return Response{}

server/etcdserver/server.go

@@ -561,8 +561,7 @@ func NewServer(cfg config.ServerConfig) (srv *EtcdServer, err error) {
 	}
 	srv.kv = mvcc.New(srv.Logger(), srv.be, srv.lessor, srv.consistIndex, mvcc.StoreConfig{CompactionBatchLimit: cfg.CompactionBatchLimit})
 	kvindex := srv.consistIndex.ConsistentIndex()
-	srv.lg.Debug("restore consistentIndex",
+	srv.lg.Debug("restore consistentIndex", zap.Uint64("index", kvindex))
-		zap.Uint64("index", kvindex))
 	if beExist {
 		// TODO: remove kvindex != 0 checking when we do not expect users to upgrade
 		// etcd from pre-3.0 release.
@@ -2018,8 +2017,13 @@ func (s *EtcdServer) apply(
 	es []raftpb.Entry,
 	confState *raftpb.ConfState,
 ) (appliedt uint64, appliedi uint64, shouldStop bool) {
+	s.lg.Debug("Applying entries", zap.Int("num-entries", len(es)))
 	for i := range es {
 		e := es[i]
+		s.lg.Debug("Applying entry",
+			zap.Uint64("index", e.Index),
+			zap.Uint64("term", e.Term),
+			zap.Stringer("type", e.Type))
 		switch e.Type {
 		case raftpb.EntryNormal:
 			s.applyEntryNormal(&e)
@@ -2028,12 +2032,14 @@ func (s *EtcdServer) apply(
 
 		case raftpb.EntryConfChange:
 			// set the consistent index of current executing entry
+			shouldApplyV3 := false
 			if e.Index > s.consistIndex.ConsistentIndex() {
 				s.consistIndex.SetConsistentIndex(e.Index)
+				shouldApplyV3 = true
 			}
 			var cc raftpb.ConfChange
 			pbutil.MustUnmarshal(&cc, e.Data)
-			removedSelf, err := s.applyConfChange(cc, confState)
+			removedSelf, err := s.applyConfChange(cc, confState, shouldApplyV3)
 			s.setAppliedIndex(e.Index)
 			s.setTerm(e.Term)
 			shouldStop = shouldStop || removedSelf
@@ -2085,18 +2091,16 @@ func (s *EtcdServer) applyEntryNormal(e *raftpb.Entry) {
 		var r pb.Request
 		rp := &r
 		pbutil.MustUnmarshal(rp, e.Data)
+		s.lg.Debug("applyEntryNormal", zap.Stringer("V2request", rp))
 		s.w.Trigger(r.ID, s.applyV2Request((*RequestV2)(rp)))
 		return
 	}
+	s.lg.Debug("applyEntryNormal", zap.Stringer("raftReq", &raftReq))
 	if raftReq.V2 != nil {
 		req := (*RequestV2)(raftReq.V2)
 		s.w.Trigger(req.ID, s.applyV2Request(req))
 		return
 	}
-	// do not re-apply applied entries.
-	if !shouldApplyV3 {
-		return
-	}
 
 	id := raftReq.ID
 	if id == 0 {
@@ -2109,7 +2113,12 @@ func (s *EtcdServer) applyEntryNormal(e *raftpb.Entry) {
 		if !needResult && raftReq.Txn != nil {
 			removeNeedlessRangeReqs(raftReq.Txn)
 		}
-		ar = s.applyV3.Apply(&raftReq)
+		ar = s.applyV3.Apply(&raftReq, shouldApplyV3)
+	}
+
+	// do not re-apply applied entries.
+	if !shouldApplyV3 {
+		return
 	}
 
 	if ar == nil {
@@ -2142,7 +2151,7 @@ func (s *EtcdServer) applyEntryNormal(e *raftpb.Entry) {
 
 // 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) (bool, error) {
+func (s *EtcdServer) applyConfChange(cc raftpb.ConfChange, confState *raftpb.ConfState, shouldApplyV3 bool) (bool, error) {
 	if err := s.cluster.ValidateConfigurationChange(cc); err != nil {
 		cc.NodeID = raft.None
 		s.r.ApplyConfChange(cc)
@@ -2165,9 +2174,9 @@ func (s *EtcdServer) applyConfChange(cc raftpb.ConfChange, confState *raftpb.Con
 			)
 		}
 		if confChangeContext.IsPromote {
-			s.cluster.PromoteMember(confChangeContext.Member.ID)
+			s.cluster.PromoteMember(confChangeContext.Member.ID, shouldApplyV3)
 		} else {
-			s.cluster.AddMember(&confChangeContext.Member)
+			s.cluster.AddMember(&confChangeContext.Member, shouldApplyV3)
 
 			if confChangeContext.Member.ID != s.id {
 				s.r.transport.AddPeer(confChangeContext.Member.ID, confChangeContext.PeerURLs)
@@ -2185,7 +2194,7 @@ func (s *EtcdServer) applyConfChange(cc raftpb.ConfChange, confState *raftpb.Con
 
 	case raftpb.ConfChangeRemoveNode:
 		id := types.ID(cc.NodeID)
-		s.cluster.RemoveMember(id)
+		s.cluster.RemoveMember(id, shouldApplyV3)
 		if id == s.id {
 			return true, nil
 		}
@@ -2203,7 +2212,7 @@ func (s *EtcdServer) applyConfChange(cc raftpb.ConfChange, confState *raftpb.Con
 				zap.String("member-id-from-message", m.ID.String()),
 			)
 		}
-		s.cluster.UpdateRaftAttributes(m.ID, m.RaftAttributes)
+		s.cluster.UpdateRaftAttributes(m.ID, m.RaftAttributes, shouldApplyV3)
 		if m.ID != s.id {
 			s.r.transport.UpdatePeer(m.ID, m.PeerURLs)
 		}

server/etcdserver/server_test.go

@@ -181,7 +181,7 @@ func TestApplyRepeat(t *testing.T) {
 	cl := newTestCluster(nil)
 	st := v2store.New()
 	cl.SetStore(v2store.New())
-	cl.AddMember(&membership.Member{ID: 1234})
+	cl.AddMember(&membership.Member{ID: 1234}, true)
 	r := newRaftNode(raftNodeConfig{
 		lg:          zap.NewExample(),
 		Node:        n,
@@ -509,9 +509,9 @@ func TestApplyConfChangeError(t *testing.T) {
 	cl := membership.NewCluster(zap.NewExample(), "")
 	cl.SetStore(v2store.New())
 	for i := 1; i <= 4; i++ {
-		cl.AddMember(&membership.Member{ID: types.ID(i)})
+		cl.AddMember(&membership.Member{ID: types.ID(i)}, true)
 	}
-	cl.RemoveMember(4)
+	cl.RemoveMember(4, true)
 
 	attr := membership.RaftAttributes{PeerURLs: []string{fmt.Sprintf("http://127.0.0.1:%d", 1)}}
 	ctx, err := json.Marshal(&membership.Member{ID: types.ID(1), RaftAttributes: attr})
@@ -576,7 +576,7 @@ func TestApplyConfChangeError(t *testing.T) {
 			r:       *newRaftNode(raftNodeConfig{lg: zap.NewExample(), Node: n}),
 			cluster: cl,
 		}
-		_, err := srv.applyConfChange(tt.cc, nil)
+		_, err := srv.applyConfChange(tt.cc, nil, true)
 		if err != tt.werr {
 			t.Errorf("#%d: applyConfChange error = %v, want %v", i, err, tt.werr)
 		}
@@ -597,7 +597,7 @@ func TestApplyConfChangeShouldStop(t *testing.T) {
 	cl := membership.NewCluster(zap.NewExample(), "")
 	cl.SetStore(v2store.New())
 	for i := 1; i <= 3; i++ {
-		cl.AddMember(&membership.Member{ID: types.ID(i)})
+		cl.AddMember(&membership.Member{ID: types.ID(i)}, true)
 	}
 	r := newRaftNode(raftNodeConfig{
 		lg:        zap.NewExample(),
@@ -616,7 +616,7 @@ func TestApplyConfChangeShouldStop(t *testing.T) {
 		NodeID: 2,
 	}
 	// remove non-local member
-	shouldStop, err := srv.applyConfChange(cc, &raftpb.ConfState{})
+	shouldStop, err := srv.applyConfChange(cc, &raftpb.ConfState{}, true)
 	if err != nil {
 		t.Fatalf("unexpected error %v", err)
 	}
@@ -626,7 +626,7 @@ func TestApplyConfChangeShouldStop(t *testing.T) {
 
 	// remove local member
 	cc.NodeID = 1
-	shouldStop, err = srv.applyConfChange(cc, &raftpb.ConfState{})
+	shouldStop, err = srv.applyConfChange(cc, &raftpb.ConfState{}, true)
 	if err != nil {
 		t.Fatalf("unexpected error %v", err)
 	}
@@ -640,7 +640,7 @@ func TestApplyConfChangeShouldStop(t *testing.T) {
 func TestApplyConfigChangeUpdatesConsistIndex(t *testing.T) {
 	cl := membership.NewCluster(zap.NewExample(), "")
 	cl.SetStore(v2store.New())
-	cl.AddMember(&membership.Member{ID: types.ID(1)})
+	cl.AddMember(&membership.Member{ID: types.ID(1)}, true)
 	r := newRaftNode(raftNodeConfig{
 		lg:        zap.NewExample(),
 		Node:      newNodeNop(),
@@ -688,7 +688,7 @@ func TestApplyMultiConfChangeShouldStop(t *testing.T) {
 	cl := membership.NewCluster(zap.NewExample(), "")
 	cl.SetStore(v2store.New())
 	for i := 1; i <= 5; i++ {
-		cl.AddMember(&membership.Member{ID: types.ID(i)})
+		cl.AddMember(&membership.Member{ID: types.ID(i)}, true)
 	}
 	r := newRaftNode(raftNodeConfig{
 		lg:        zap.NewExample(),
@@ -1342,7 +1342,7 @@ func TestRemoveMember(t *testing.T) {
 	cl := newTestCluster(nil)
 	st := v2store.New()
 	cl.SetStore(v2store.New())
-	cl.AddMember(&membership.Member{ID: 1234})
+	cl.AddMember(&membership.Member{ID: 1234}, true)
 	r := newRaftNode(raftNodeConfig{
 		lg:          zap.NewExample(),
 		Node:        n,
@@ -1386,7 +1386,7 @@ func TestUpdateMember(t *testing.T) {
 	cl := newTestCluster(nil)
 	st := v2store.New()
 	cl.SetStore(st)
-	cl.AddMember(&membership.Member{ID: 1234})
+	cl.AddMember(&membership.Member{ID: 1234}, true)
 	r := newRaftNode(raftNodeConfig{
 		lg:          zap.NewExample(),
 		Node:        n,
@@ -1874,7 +1874,7 @@ func (n *nodeCommitter) Propose(ctx context.Context, data []byte) error {
 func newTestCluster(membs []*membership.Member) *membership.RaftCluster {
 	c := membership.NewCluster(zap.NewExample(), "")
 	for _, m := range membs {
-		c.AddMember(m)
+		c.AddMember(m, true)
 	}
 	return c
 }

server/mvcc/kvstore.go

@@ -43,7 +43,6 @@ var (
 
 	ErrCompacted = errors.New("mvcc: required revision has been compacted")
 	ErrFutureRev = errors.New("mvcc: required revision is a future revision")
-	ErrCanceled  = errors.New("mvcc: watcher is canceled")
 )
 
 const (
@@ -438,6 +437,10 @@ func (s *store) restore() error {
 
 	tx.Unlock()
 
+	s.lg.Info("kvstore restored",
+		zap.Uint64("consistent-index", s.ConsistentIndex()),
+		zap.Int64("current-rev", s.currentRev))
+
 	if scheduledCompact != 0 {
 		if _, err := s.compactLockfree(scheduledCompact); err != nil {
 			s.lg.Warn("compaction encountered error", zap.Error(err))

tests/go.mod

@@ -26,6 +26,7 @@ require (
 	github.com/soheilhy/cmux v0.1.5
 	github.com/spf13/cobra v1.1.1
 	github.com/spf13/pflag v1.0.5
+	github.com/stretchr/testify v1.5.1
 	go.etcd.io/bbolt v1.3.5
 	go.etcd.io/etcd/api/v3 v3.5.0-alpha.0
 	go.etcd.io/etcd/client/pkg/v3 v3.5.0-alpha.0

tests/integration/clientv3/ordering_kv_test.go

@@ -20,13 +20,14 @@ import (
 	"testing"
 	"time"
 
+	"github.com/stretchr/testify/assert"
 	"go.etcd.io/etcd/client/v3"
 	"go.etcd.io/etcd/client/v3/ordering"
 	"go.etcd.io/etcd/tests/v3/integration"
 )
 
 func TestDetectKvOrderViolation(t *testing.T) {
-	var errOrderViolation = errors.New("Detected Order Violation")
+	var errOrderViolation = errors.New("DetectedOrderViolation")
 
 	integration.BeforeTest(t)
 	clus := integration.NewClusterV3(t, &integration.ClusterConfig{Size: 3})
@@ -43,7 +44,7 @@ func TestDetectKvOrderViolation(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	defer cli.Close()
+	defer func() { assert.NoError(t, cli.Close()) }()
 	ctx := context.TODO()
 
 	if _, err = clus.Client(0).Put(ctx, "foo", "bar"); err != nil {
@@ -69,27 +70,31 @@ func TestDetectKvOrderViolation(t *testing.T) {
 		func(op clientv3.Op, resp clientv3.OpResponse, prevRev int64) error {
 			return errOrderViolation
 		})
-	_, err = orderingKv.Get(ctx, "foo")
+	v, err := orderingKv.Get(ctx, "foo")
 	if err != nil {
 		t.Fatal(err)
 	}
+	t.Logf("Read from the first member: v:%v err:%v", v, err)
+	assert.Equal(t, []byte("buzz"), v.Kvs[0].Value)
 
 	// ensure that only the third member is queried during requests
 	clus.Members[0].Stop(t)
 	clus.Members[1].Stop(t)
-	clus.Members[2].Restart(t)
+	assert.NoError(t, clus.Members[2].Restart(t))
 	// force OrderingKv to query the third member
 	cli.SetEndpoints(clus.Members[2].GRPCAddr())
 	time.Sleep(2 * time.Second) // FIXME: Figure out how pause SetEndpoints sufficiently that this is not needed
 
-	_, err = orderingKv.Get(ctx, "foo", clientv3.WithSerializable())
+	t.Logf("Quering m2 after restart")
+	v, err = orderingKv.Get(ctx, "foo", clientv3.WithSerializable())
+	t.Logf("Quering m2 returned: v:%v erro:%v ", v, err)
 	if err != errOrderViolation {
-		t.Fatalf("expected %v, got %v", errOrderViolation, err)
+		t.Fatalf("expected %v, got err:%v v:%v", errOrderViolation, err, v)
 	}
 }
 
 func TestDetectTxnOrderViolation(t *testing.T) {
-	var errOrderViolation = errors.New("Detected Order Violation")
+	var errOrderViolation = errors.New("DetectedOrderViolation")
 
 	integration.BeforeTest(t)
 	clus := integration.NewClusterV3(t, &integration.ClusterConfig{Size: 3})
@@ -106,7 +111,7 @@ func TestDetectTxnOrderViolation(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	defer cli.Close()
+	defer func() { assert.NoError(t, cli.Close()) }()
 	ctx := context.TODO()
 
 	if _, err = clus.Client(0).Put(ctx, "foo", "bar"); err != nil {
@@ -144,7 +149,7 @@ func TestDetectTxnOrderViolation(t *testing.T) {
 	// ensure that only the third member is queried during requests
 	clus.Members[0].Stop(t)
 	clus.Members[1].Stop(t)
-	clus.Members[2].Restart(t)
+	assert.NoError(t, clus.Members[2].Restart(t))
 	// force OrderingKv to query the third member
 	cli.SetEndpoints(clus.Members[2].GRPCAddr())
 	time.Sleep(2 * time.Second) // FIXME: Figure out how pause SetEndpoints sufficiently that this is not needed