validate conf change against v3store instead of v2store

Signed-off-by: Benjamin Wang <[email protected]>

server/etcdserver/api/membership/cluster.go

@@ -300,9 +300,13 @@ 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.
-	membersMap, removedMap := membersFromStore(c.lg, c.v2store)
+func (c *RaftCluster) ValidateConfigurationChange(cc raftpb.ConfChange, shouldApplyV3 ShouldApplyV3) error {
+	// It makes no sense to validate a confChange if we don't apply it.
+	if !shouldApplyV3 {
+		return nil
+	}
+	membersMap, removedMap := c.be.MustReadMembersFromBackend()
+
 	id := types.ID(cc.NodeID)
 	if removedMap[id] {
 		return ErrIDRemoved

server/etcdserver/api/membership/cluster_test.go

@@ -278,6 +278,8 @@ func TestClusterValidateAndAssignIDs(t *testing.T) {
 
 func TestClusterValidateConfigurationChange(t *testing.T) {
 	cl := NewCluster(zaptest.NewLogger(t), WithMaxLearners(1))
+	be := newMembershipBackend()
+	cl.SetBackend(be)
 	cl.SetStore(v2store.New())
 	for i := 1; i <= 4; i++ {
 		var isLearner bool
@@ -455,7 +457,7 @@ func TestClusterValidateConfigurationChange(t *testing.T) {
 		},
 	}
 	for i, tt := range tests {
-		err := cl.ValidateConfigurationChange(tt.cc)
+		err := cl.ValidateConfigurationChange(tt.cc, true)
 		if err != tt.werr {
 			t.Errorf("#%d: validateConfigurationChange error = %v, want %v", i, err, tt.werr)
 		}

server/etcdserver/server.go

@@ -1935,7 +1935,7 @@ func removeNeedlessRangeReqs(txn *pb.TxnRequest) {
 // 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) {
-	if err := s.cluster.ValidateConfigurationChange(cc); err != nil {
+	if err := s.cluster.ValidateConfigurationChange(cc, shouldApplyV3); err != nil {
 		cc.NodeID = raft.None
 		s.r.ApplyConfChange(cc)