raft: allow use of joint quorums

clientv3/snapshot/v3_snapshot.go

@@ -28,6 +28,7 @@ import (
 	"strings"
 	"time"
 
+	bolt "go.etcd.io/bbolt"
 	"go.etcd.io/etcd/clientv3"
 	"go.etcd.io/etcd/etcdserver"
 	"go.etcd.io/etcd/etcdserver/api/membership"
@@ -43,8 +44,6 @@ import (
 	"go.etcd.io/etcd/raft/raftpb"
 	"go.etcd.io/etcd/wal"
 	"go.etcd.io/etcd/wal/walpb"
-
-	bolt "go.etcd.io/bbolt"
 	"go.uber.org/zap"
 )
 
@@ -482,7 +481,7 @@ func (s *v3Manager) saveWALAndSnap() error {
 			Index: commit,
 			Term:  term,
 			ConfState: raftpb.ConfState{
-				Nodes: nodeIDs,
+				Voters: nodeIDs,
 			},
 		},
 	}

etcdserver/api/snap/snapshotter_test.go

@@ -24,15 +24,14 @@ import (
 	"testing"
 
 	"go.etcd.io/etcd/raft/raftpb"
-
 	"go.uber.org/zap"
 )
 
 var testSnap = &raftpb.Snapshot{
 	Data: []byte("some snapshot"),
 	Metadata: raftpb.SnapshotMetadata{
 		ConfState: raftpb.ConfState{
-			Nodes: []uint64{1, 2, 3},
+			Voters: []uint64{1, 2, 3},
 		},
 		Index: 1,
 		Term:  1,

etcdserver/raft.go

@@ -647,7 +647,7 @@ func restartAsStandaloneNode(cfg ServerConfig, snapshot *raftpb.Snapshot) (types
 func getIDs(lg *zap.Logger, snap *raftpb.Snapshot, ents []raftpb.Entry) []uint64 {
 	ids := make(map[uint64]bool)
 	if snap != nil {
-		for _, id := range snap.Metadata.ConfState.Nodes {
+		for _, id := range snap.Metadata.ConfState.Voters {
 			ids[id] = true
 		}
 	}

etcdserver/raft_test.go

@@ -46,17 +46,17 @@ func TestGetIDs(t *testing.T) {
 		widSet []uint64
 	}{
 		{nil, []raftpb.Entry{}, []uint64{}},
-		{&raftpb.ConfState{Nodes: []uint64{1}},
+		{&raftpb.ConfState{Voters: []uint64{1}},
 			[]raftpb.Entry{}, []uint64{1}},
-		{&raftpb.ConfState{Nodes: []uint64{1}},
+		{&raftpb.ConfState{Voters: []uint64{1}},
 			[]raftpb.Entry{addEntry}, []uint64{1, 2}},
-		{&raftpb.ConfState{Nodes: []uint64{1}},
+		{&raftpb.ConfState{Voters: []uint64{1}},
 			[]raftpb.Entry{addEntry, removeEntry}, []uint64{1}},
-		{&raftpb.ConfState{Nodes: []uint64{1}},
+		{&raftpb.ConfState{Voters: []uint64{1}},
 			[]raftpb.Entry{addEntry, normalEntry}, []uint64{1, 2}},
-		{&raftpb.ConfState{Nodes: []uint64{1}},
+		{&raftpb.ConfState{Voters: []uint64{1}},
 			[]raftpb.Entry{addEntry, normalEntry, updateEntry}, []uint64{1, 2}},
-		{&raftpb.ConfState{Nodes: []uint64{1}},
+		{&raftpb.ConfState{Voters: []uint64{1}},
 			[]raftpb.Entry{addEntry, removeEntry, normalEntry}, []uint64{1}},
 	}
 
@@ -178,8 +178,8 @@ func TestStopRaftWhenWaitingForApplyDone(t *testing.T) {
 	}
 }
 
-// TestConfgChangeBlocksApply ensures apply blocks if committed entries contain config-change.
-func TestConfgChangeBlocksApply(t *testing.T) {
+// TestConfigChangeBlocksApply ensures apply blocks if committed entries contain config-change.
+func TestConfigChangeBlocksApply(t *testing.T) {
 	n := newNopReadyNode()
 
 	r := newRaftNode(raftNodeConfig{

etcdserver/server_test.go

@@ -28,8 +28,6 @@ import (
 	"testing"
 	"time"
 
-	"go.uber.org/zap"
-
 	"go.etcd.io/etcd/etcdserver/api/membership"
 	"go.etcd.io/etcd/etcdserver/api/rafthttp"
 	"go.etcd.io/etcd/etcdserver/api/snap"
@@ -49,6 +47,7 @@ import (
 	"go.etcd.io/etcd/pkg/wait"
 	"go.etcd.io/etcd/raft"
 	"go.etcd.io/etcd/raft/raftpb"
+	"go.uber.org/zap"
 )
 
 // TestDoLocalAction tests requests which do not need to go through raft to be applied,
@@ -1017,7 +1016,7 @@ func TestSnapshot(t *testing.T) {
 		}
 	}()
 
-	srv.snapshot(1, raftpb.ConfState{Nodes: []uint64{1}})
+	srv.snapshot(1, raftpb.ConfState{Voters: []uint64{1}})
 	<-ch
 	<-ch
 }
@@ -1632,7 +1631,7 @@ func (n *nodeRecorder) Propose(ctx context.Context, data []byte) error {
 	n.Record(testutil.Action{Name: "Propose", Params: []interface{}{data}})
 	return nil
 }
-func (n *nodeRecorder) ProposeConfChange(ctx context.Context, conf raftpb.ConfChange) error {
+func (n *nodeRecorder) ProposeConfChange(ctx context.Context, conf raftpb.ConfChangeI) error {
 	n.Record(testutil.Action{Name: "ProposeConfChange"})
 	return nil
 }
@@ -1645,7 +1644,7 @@ func (n *nodeRecorder) Ready() <-chan raft.Ready
 func (n *nodeRecorder) TransferLeadership(ctx context.Context, lead, transferee uint64) {}
 func (n *nodeRecorder) ReadIndex(ctx context.Context, rctx []byte) error                { return nil }
 func (n *nodeRecorder) Advance()                                                        {}
-func (n *nodeRecorder) ApplyConfChange(conf raftpb.ConfChange) *raftpb.ConfState {
+func (n *nodeRecorder) ApplyConfChange(conf raftpb.ConfChangeI) *raftpb.ConfState {
 	n.Record(testutil.Action{Name: "ApplyConfChange", Params: []interface{}{conf}})
 	return &raftpb.ConfState{}
 }
@@ -1706,21 +1705,37 @@ func newNodeConfChangeCommitterStream() *nodeConfChangeCommitterRecorder {
 	return &nodeConfChangeCommitterRecorder{*newReadyNode(), 0}
 }
 
-func (n *nodeConfChangeCommitterRecorder) ProposeConfChange(ctx context.Context, conf raftpb.ConfChange) error {
-	data, err := conf.Marshal()
+func confChangeActionName(conf raftpb.ConfChangeI) string {
+	var s string
+	if confV1, ok := conf.AsV1(); ok {
+		s = confV1.Type.String()
+	} else {
+		for i, chg := range conf.AsV2().Changes {
+			if i > 0 {
+				s += "/"
+			}
+			s += chg.Type.String()
+		}
+	}
+	return s
+}
+
+func (n *nodeConfChangeCommitterRecorder) ProposeConfChange(ctx context.Context, conf raftpb.ConfChangeI) error {
+	typ, data, err := raftpb.MarshalConfChange(conf)
 	if err != nil {
 		return err
 	}
+
 	n.index++
-	n.Record(testutil.Action{Name: "ProposeConfChange:" + conf.Type.String()})
-	n.readyc <- raft.Ready{CommittedEntries: []raftpb.Entry{{Index: n.index, Type: raftpb.EntryConfChange, Data: data}}}
+	n.Record(testutil.Action{Name: "ProposeConfChange:" + confChangeActionName(conf)})
+	n.readyc <- raft.Ready{CommittedEntries: []raftpb.Entry{{Index: n.index, Type: typ, Data: data}}}
 	return nil
 }
 func (n *nodeConfChangeCommitterRecorder) Ready() <-chan raft.Ready {
 	return n.readyc
 }
-func (n *nodeConfChangeCommitterRecorder) ApplyConfChange(conf raftpb.ConfChange) *raftpb.ConfState {
-	n.Record(testutil.Action{Name: "ApplyConfChange:" + conf.Type.String()})
+func (n *nodeConfChangeCommitterRecorder) ApplyConfChange(conf raftpb.ConfChangeI) *raftpb.ConfState {
+	n.Record(testutil.Action{Name: "ApplyConfChange:" + confChangeActionName(conf)})
 	return &raftpb.ConfState{}
 }
 

raft/bootstrap.go

@@ -74,7 +74,7 @@ func (rn *RawNode) Bootstrap(peers []Peer) error {
 	// the invariant that committed < unstable?
 	rn.raft.raftLog.committed = uint64(len(ents))
 	for _, peer := range peers {
-		rn.raft.applyConfChange(pb.ConfChange{NodeID: peer.ID, Type: pb.ConfChangeAddNode})
+		rn.raft.applyConfChange(pb.ConfChange{NodeID: peer.ID, Type: pb.ConfChangeAddNode}.AsV2())
 	}
 	return nil
 }

raft/confchange/confchange.go

@@ -41,12 +41,12 @@ type Changer struct {
 // to
 //     (1 2 3)&&(1 2 3).
 //
-// The supplied ConfChanges are then applied to the incoming majority config,
+// The supplied changes are then applied to the incoming majority config,
 // resulting in a joint configuration that in terms of the Raft thesis[1]
 // (Section 4.3) corresponds to `C_{new,old}`.
 //
 // [1]: https://github.com/ongardie/dissertation/blob/master/online-trim.pdf
-func (c Changer) EnterJoint(ccs ...pb.ConfChange) (tracker.Config, tracker.ProgressMap, error) {
+func (c Changer) EnterJoint(autoLeave bool, ccs ...pb.ConfChangeSingle) (tracker.Config, tracker.ProgressMap, error) {
 	cfg, prs, err := c.checkAndCopy()
 	if err != nil {
 		return c.err(err)
@@ -74,7 +74,7 @@ func (c Changer) EnterJoint(ccs ...pb.ConfChange) (tracker.Config, tracker.Progr
 	if err := c.apply(&cfg, prs, ccs...); err != nil {
 		return c.err(err)
 	}
-
+	cfg.AutoLeave = autoLeave
 	return checkAndReturn(cfg, prs)
 }
 
@@ -120,6 +120,7 @@ func (c Changer) LeaveJoint() (tracker.Config, tracker.ProgressMap, error) {
 		}
 	}
 	*outgoingPtr(&cfg.Voters) = nil
+	cfg.AutoLeave = false
 
 	return checkAndReturn(cfg, prs)
 }
@@ -129,7 +130,7 @@ func (c Changer) LeaveJoint() (tracker.Config, tracker.ProgressMap, error) {
 // will return an error if that is not the case, if the resulting quorum is
 // zero, or if the configuration is in a joint state (i.e. if there is an
 // outgoing configuration).
-func (c Changer) Simple(ccs ...pb.ConfChange) (tracker.Config, tracker.ProgressMap, error) {
+func (c Changer) Simple(ccs ...pb.ConfChangeSingle) (tracker.Config, tracker.ProgressMap, error) {
 	cfg, prs, err := c.checkAndCopy()
 	if err != nil {
 		return c.err(err)
@@ -142,7 +143,7 @@ func (c Changer) Simple(ccs ...pb.ConfChange) (tracker.Config, tracker.ProgressM
 		return c.err(err)
 	}
 	if n := symdiff(incoming(c.Tracker.Voters), incoming(cfg.Voters)); n > 1 {
-		return tracker.Config{}, nil, errors.New("more than voter changed without entering joint config")
+		return tracker.Config{}, nil, errors.New("more than one voter changed without entering joint config")
 	}
 	if err := checkInvariants(cfg, prs); err != nil {
 		return tracker.Config{}, tracker.ProgressMap{}, nil
@@ -151,14 +152,14 @@ func (c Changer) Simple(ccs ...pb.ConfChange) (tracker.Config, tracker.ProgressM
 	return checkAndReturn(cfg, prs)
 }
 
-// apply a ConfChange to the configuration. By convention, changes to voters are
+// apply a change to the configuration. By convention, changes to voters are
 // always made to the incoming majority config Voters[0]. Voters[1] is either
 // empty or preserves the outgoing majority configuration while in a joint state.
-func (c Changer) apply(cfg *tracker.Config, prs tracker.ProgressMap, ccs ...pb.ConfChange) error {
+func (c Changer) apply(cfg *tracker.Config, prs tracker.ProgressMap, ccs ...pb.ConfChangeSingle) error {
 	for _, cc := range ccs {
 		if cc.NodeID == 0 {
 			// etcd replaces the NodeID with zero if it decides (downstream of
-			// raft) to not apply a ConfChange, so we have to have explicit code
+			// raft) to not apply a change, so we have to have explicit code
 			// here to ignore these.
 			continue
 		}
@@ -327,6 +328,9 @@ func checkInvariants(cfg tracker.Config, prs tracker.ProgressMap) error {
 		if cfg.LearnersNext != nil {
 			return fmt.Errorf("LearnersNext must be nil when not joint")
 		}
+		if cfg.AutoLeave {
+			return fmt.Errorf("AutoLeave must be false when not joint")
+		}
 	}
 
 	return nil
@@ -408,7 +412,7 @@ func outgoingPtr(voters *quorum.JointConfig) *quorum.MajorityConfig { return &vo
 
 // Describe prints the type and NodeID of the configuration changes as a
 // space-delimited string.
-func Describe(ccs ...pb.ConfChange) string {
+func Describe(ccs ...pb.ConfChangeSingle) string {
 	var buf strings.Builder
 	for _, cc := range ccs {
 		if buf.Len() > 0 {

raft/confchange/datadriven_test.go

@@ -48,7 +48,7 @@ func TestConfChangeDataDriven(t *testing.T) {
 			defer func() {
 				c.LastIndex++
 			}()
-			var ccs []pb.ConfChange
+			var ccs []pb.ConfChangeSingle
 			toks := strings.Split(strings.TrimSpace(d.Input), " ")
 			if toks[0] == "" {
 				toks = nil
@@ -57,7 +57,7 @@ func TestConfChangeDataDriven(t *testing.T) {
 				if len(tok) < 2 {
 					return fmt.Sprintf("unknown token %s", tok)
 				}
-				var cc pb.ConfChange
+				var cc pb.ConfChangeSingle
 				switch tok[0] {
 				case 'v':
 					cc.Type = pb.ConfChangeAddNode
@@ -85,7 +85,11 @@ func TestConfChangeDataDriven(t *testing.T) {
 			case "simple":
 				cfg, prs, err = c.Simple(ccs...)
 			case "enter-joint":
-				cfg, prs, err = c.EnterJoint(ccs...)
+				var autoLeave bool
+				if len(d.CmdArgs) > 0 {
+					d.ScanArgs(t, "autoleave", &autoLeave)
+				}
+				cfg, prs, err = c.EnterJoint(autoLeave, ccs...)
 			case "leave-joint":
 				if len(ccs) > 0 {
 					err = errors.New("this command takes no input")