Merge pull request etcd-io#3 from jingyih/add_learner_etcdserver

etcdserver: support MemberAdd for learner

etcdserver/api/membership/cluster.go

@@ -59,10 +59,12 @@ type RaftCluster struct {
 	removed map[types.ID]bool
 }
 
+// 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) (*RaftCluster, error) {
 	c := NewCluster(lg, token)
 	for name, urls := range urlsmap {
-		m := NewMember(name, urls, token, nil)
+		m := NewMember(name, urls, token, nil, false)
 		if _, ok := c.members[m.ID]; ok {
 			return nil, fmt.Errorf("member exists with identical ID %v", m)
 		}
@@ -259,7 +261,7 @@ func (c *RaftCluster) ValidateConfigurationChange(cc raftpb.ConfChange) error {
 		return ErrIDRemoved
 	}
 	switch cc.Type {
-	case raftpb.ConfChangeAddNode:
+	case raftpb.ConfChangeAddNode, raftpb.ConfChangeAddLearnerNode:
 		if members[id] != nil {
 			return ErrIDExists
 		}

etcdserver/api/membership/cluster_test.go

@@ -472,6 +472,29 @@ func TestClusterAddMember(t *testing.T) {
 	}
 }
 
+func TestClusterAddMemberAsLearner(t *testing.T) {
+	st := mockstore.NewRecorder()
+	c := newTestCluster(nil)
+	c.SetStore(st)
+	c.AddMember(newTestMemberAsLearner(1, nil, "node1", nil))
+
+	wactions := []testutil.Action{
+		{
+			Name: "Create",
+			Params: []interface{}{
+				path.Join(StoreMembersPrefix, "1", "raftAttributes"),
+				false,
+				`{"peerURLs":null,"isLearner":true}`,
+				false,
+				v2store.TTLOptionSet{ExpireTime: v2store.Permanent},
+			},
+		},
+	}
+	if g := st.Action(); !reflect.DeepEqual(g, wactions) {
+		t.Errorf("actions = %v, want %v", g, wactions)
+	}
+}
+
 func TestClusterMembers(t *testing.T) {
 	cls := &RaftCluster{
 		members: map[types.ID]*Member{

etcdserver/api/membership/member.go

@@ -35,6 +35,8 @@ 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.
@@ -51,10 +53,13 @@ type Member struct {
 
 // 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 {
+func NewMember(name string, peerURLs types.URLs, clusterName string, now *time.Time, isLearner bool) *Member {
 	m := &Member{
-		RaftAttributes: RaftAttributes{PeerURLs: peerURLs.StringSlice()},
-		Attributes:     Attributes{Name: name},
+		RaftAttributes: RaftAttributes{
+			PeerURLs:  peerURLs.StringSlice(),
+			IsLearner: isLearner,
+		},
+		Attributes: Attributes{Name: name},
 	}
 
 	var b []byte
@@ -88,6 +93,9 @@ func (m *Member) Clone() *Member {
 	}
 	mm := &Member{
 		ID: m.ID,
+		RaftAttributes: RaftAttributes{
+			IsLearner: m.IsLearner,
+		},
 		Attributes: Attributes{
 			Name: m.Name,
 		},

etcdserver/api/membership/member_test.go

@@ -36,17 +36,17 @@ func TestMemberTime(t *testing.T) {
 		mem *Member
 		id  types.ID
 	}{
-		{NewMember("mem1", []url.URL{{Scheme: "http", Host: "10.0.0.8:2379"}}, "", nil), 14544069596553697298},
+		{NewMember("mem1", []url.URL{{Scheme: "http", Host: "10.0.0.8:2379"}}, "", nil, false), 14544069596553697298},
 		// Same ID, different name (names shouldn't matter)
-		{NewMember("memfoo", []url.URL{{Scheme: "http", Host: "10.0.0.8:2379"}}, "", nil), 14544069596553697298},
+		{NewMember("memfoo", []url.URL{{Scheme: "http", Host: "10.0.0.8:2379"}}, "", nil, false), 14544069596553697298},
 		// Same ID, different Time
-		{NewMember("mem1", []url.URL{{Scheme: "http", Host: "10.0.0.8:2379"}}, "", timeParse("1984-12-23T15:04:05Z")), 2448790162483548276},
+		{NewMember("mem1", []url.URL{{Scheme: "http", Host: "10.0.0.8:2379"}}, "", timeParse("1984-12-23T15:04:05Z"), false), 2448790162483548276},
 		// Different cluster name
-		{NewMember("mcm1", []url.URL{{Scheme: "http", Host: "10.0.0.8:2379"}}, "etcd", timeParse("1984-12-23T15:04:05Z")), 6973882743191604649},
-		{NewMember("mem1", []url.URL{{Scheme: "http", Host: "10.0.0.1:2379"}}, "", timeParse("1984-12-23T15:04:05Z")), 1466075294948436910},
+		{NewMember("mcm1", []url.URL{{Scheme: "http", Host: "10.0.0.8:2379"}}, "etcd", timeParse("1984-12-23T15:04:05Z"), false), 6973882743191604649},
+		{NewMember("mem1", []url.URL{{Scheme: "http", Host: "10.0.0.1:2379"}}, "", timeParse("1984-12-23T15:04:05Z"), false), 1466075294948436910},
 		// Order shouldn't matter
-		{NewMember("mem1", []url.URL{{Scheme: "http", Host: "10.0.0.1:2379"}, {Scheme: "http", Host: "10.0.0.2:2379"}}, "", nil), 16552244735972308939},
-		{NewMember("mem1", []url.URL{{Scheme: "http", Host: "10.0.0.2:2379"}, {Scheme: "http", Host: "10.0.0.1:2379"}}, "", nil), 16552244735972308939},
+		{NewMember("mem1", []url.URL{{Scheme: "http", Host: "10.0.0.1:2379"}, {Scheme: "http", Host: "10.0.0.2:2379"}}, "", nil, false), 16552244735972308939},
+		{NewMember("mem1", []url.URL{{Scheme: "http", Host: "10.0.0.2:2379"}, {Scheme: "http", Host: "10.0.0.1:2379"}}, "", nil, false), 16552244735972308939},
 	}
 	for i, tt := range tests {
 		if tt.mem.ID != tt.id {
@@ -113,3 +113,11 @@ func newTestMember(id uint64, peerURLs []string, name string, clientURLs []strin
 		Attributes:     Attributes{Name: name, ClientURLs: clientURLs},
 	}
 }
+
+func newTestMemberAsLearner(id uint64, peerURLs []string, name string, clientURLs []string) *Member {
+	return &Member{
+		ID:             types.ID(id),
+		RaftAttributes: RaftAttributes{PeerURLs: peerURLs, IsLearner: true},
+		Attributes:     Attributes{Name: name, ClientURLs: clientURLs},
+	}
+}

etcdserver/api/v2http/client.go

@@ -238,7 +238,7 @@ func (h *membersHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 			return
 		}
 		now := h.clock.Now()
-		m := membership.NewMember("", req.PeerURLs, "", &now)
+		m := membership.NewMember("", req.PeerURLs, "", &now, false) // does not support adding learner via v2http
 		_, err := h.server.AddMember(ctx, *m)
 		switch {
 		case err == membership.ErrIDExists || err == membership.ErrPeerURLexists:

etcdserver/api/v3rpc/member.go

@@ -46,15 +46,19 @@ func (cs *ClusterServer) MemberAdd(ctx context.Context, r *pb.MemberAddRequest)
 	}
 
 	now := time.Now()
-	m := membership.NewMember("", urls, "", &now)
+	m := membership.NewMember("", urls, "", &now, r.IsLearner)
 	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},
+		Header: cs.header(),
+		Member: &pb.Member{
+			ID:        uint64(m.ID),
+			PeerURLs:  m.PeerURLs,
+			IsLearner: m.IsLearner,
+		},
 		Members: membersToProtoMembers(membs),
 	}, nil
 }
@@ -101,6 +105,7 @@ func membersToProtoMembers(membs []*membership.Member) []*pb.Member {
 			ID:         uint64(membs[i].ID),
 			PeerURLs:   membs[i].PeerURLs,
 			ClientURLs: membs[i].ClientURLs,
+			IsLearner:  membs[i].IsLearner,
 		}
 	}
 	return protoMembs

etcdserver/server.go

@@ -1544,6 +1544,7 @@ func (s *EtcdServer) AddMember(ctx context.Context, memb membership.Member) ([]*
 		return nil, err
 	}
 
+	// TODO: might switch to less strict check when adding raft learner
 	if s.Cfg.StrictReconfigCheck {
 		// by default StrictReconfigCheck is enabled; reject new members if unhealthy
 		if !s.cluster.IsReadyToAddNewMember() {
@@ -1585,6 +1586,11 @@ func (s *EtcdServer) AddMember(ctx context.Context, memb membership.Member) ([]*
 		NodeID:  uint64(memb.ID),
 		Context: b,
 	}
+
+	if memb.IsLearner {
+		cc.Type = raftpb.ConfChangeAddLearnerNode
+	}
+
 	return s.configure(ctx, cc)
 }
 
@@ -2054,7 +2060,7 @@ func (s *EtcdServer) applyConfChange(cc raftpb.ConfChange, confState *raftpb.Con
 	lg := s.getLogger()
 	*confState = *s.r.ApplyConfChange(cc)
 	switch cc.Type {
-	case raftpb.ConfChangeAddNode:
+	case raftpb.ConfChangeAddNode, raftpb.ConfChangeAddLearnerNode:
 		m := new(membership.Member)
 		if err := json.Unmarshal(cc.Context, m); err != nil {
 			if lg != nil {

etcdserver/server_test.go

@@ -634,7 +634,7 @@ func TestApplyConfigChangeUpdatesConsistIndex(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	m := membership.NewMember("", urls, "", &now)
+	m := membership.NewMember("", urls, "", &now, false)
 	m.ID = types.ID(2)
 	b, err := json.Marshal(m)
 	if err != nil {
@@ -1564,23 +1564,23 @@ func TestGetOtherPeerURLs(t *testing.T) {
 	}{
 		{
 			[]*membership.Member{
-				membership.NewMember("1", types.MustNewURLs([]string{"http://10.0.0.1:1"}), "a", nil),
+				membership.NewMember("1", types.MustNewURLs([]string{"http://10.0.0.1:1"}), "a", nil, false),
 			},
 			[]string{},
 		},
 		{
 			[]*membership.Member{
-				membership.NewMember("1", types.MustNewURLs([]string{"http://10.0.0.1:1"}), "a", nil),
-				membership.NewMember("2", types.MustNewURLs([]string{"http://10.0.0.2:2"}), "a", nil),
-				membership.NewMember("3", types.MustNewURLs([]string{"http://10.0.0.3:3"}), "a", nil),
+				membership.NewMember("1", types.MustNewURLs([]string{"http://10.0.0.1:1"}), "a", nil, false),
+				membership.NewMember("2", types.MustNewURLs([]string{"http://10.0.0.2:2"}), "a", nil, false),
+				membership.NewMember("3", types.MustNewURLs([]string{"http://10.0.0.3:3"}), "a", nil, false),
 			},
 			[]string{"http://10.0.0.2:2", "http://10.0.0.3:3"},
 		},
 		{
 			[]*membership.Member{
-				membership.NewMember("1", types.MustNewURLs([]string{"http://10.0.0.1:1"}), "a", nil),
-				membership.NewMember("3", types.MustNewURLs([]string{"http://10.0.0.3:3"}), "a", nil),
-				membership.NewMember("2", types.MustNewURLs([]string{"http://10.0.0.2:2"}), "a", nil),
+				membership.NewMember("1", types.MustNewURLs([]string{"http://10.0.0.1:1"}), "a", nil, false),
+				membership.NewMember("3", types.MustNewURLs([]string{"http://10.0.0.3:3"}), "a", nil, false),
+				membership.NewMember("2", types.MustNewURLs([]string{"http://10.0.0.2:2"}), "a", nil, false),
 			},
 			[]string{"http://10.0.0.2:2", "http://10.0.0.3:3"},
 		},