refactor(peer_server): remove standby mode in peer server

server/demote_command.go

@@ -1,70 +0,0 @@
-package server
-
-import (
-	"fmt"
-
-	"github.com/coreos/etcd/log"
-	"github.com/coreos/etcd/third_party/github.com/goraft/raft"
-)
-
-func init() {
-	raft.RegisterCommand(&DemoteCommand{})
-}
-
-// DemoteCommand represents a command to change a peer to a standby.
-type DemoteCommand struct {
-	Name string `json:"name"`
-}
-
-// CommandName returns the name of the command.
-func (c *DemoteCommand) CommandName() string {
-	return "etcd:demote"
-}
-
-// Apply executes the command.
-func (c *DemoteCommand) Apply(context raft.Context) (interface{}, error) {
-	ps, _ := context.Server().Context().(*PeerServer)
-
-	// Ignore this command if there is no peer.
-	if !ps.registry.PeerExists(c.Name) {
-		return nil, fmt.Errorf("peer does not exist: %s", c.Name)
-	}
-
-	// Save URLs.
-	clientURL, _ := ps.registry.ClientURL(c.Name)
-	peerURL, _ := ps.registry.PeerURL(c.Name)
-
-	// Remove node from the shared registry.
-	err := ps.registry.UnregisterPeer(c.Name)
-	if err != nil {
-		log.Debugf("Demote peer %s: Error while unregistering (%v)", c.Name, err)
-		return nil, err
-	}
-
-	// Delete from stats
-	delete(ps.followersStats.Followers, c.Name)
-
-	// Remove peer in raft
-	err = context.Server().RemovePeer(c.Name)
-	if err != nil {
-		log.Debugf("Demote peer %s: (%v)", c.Name, err)
-		return nil, err
-	}
-
-	// Register node as a standby.
-	ps.registry.RegisterStandby(c.Name, peerURL, clientURL)
-
-	// Update mode if this change applies to this server.
-	if c.Name == ps.Config.Name {
-		log.Infof("Demote peer %s: Set mode to standby with %s", c.Name, ps.server.Leader())
-		ps.standbyPeerURL, _ = ps.registry.PeerURL(ps.server.Leader())
-		go ps.setMode(StandbyMode)
-	}
-
-	return nil, nil
-}
-
-// NodeName returns the name of the affected node.
-func (c *DemoteCommand) NodeName() string {
-	return c.Name
-}

server/join_command.go

@@ -2,7 +2,6 @@ package server
 
 import (
 	"encoding/binary"
-	"encoding/json"
 
 	etcdErr "github.com/coreos/etcd/error"
 	"github.com/coreos/etcd/log"
@@ -10,13 +9,12 @@ import (
 )
 
 func init() {
-	raft.RegisterCommand(&JoinCommandV1{})
-	raft.RegisterCommand(&JoinCommandV2{})
+	raft.RegisterCommand(&JoinCommand{})
 }
 
-// JoinCommandV1 represents a request to join the cluster.
+// JoinCommand represents a request to join the cluster.
 // The command returns the join_index (Uvarint).
-type JoinCommandV1 struct {
+type JoinCommand struct {
 	MinVersion int    `json:"minVersion"`
 	MaxVersion int    `json:"maxVersion"`
 	Name       string `json:"name"`
@@ -25,27 +23,30 @@ type JoinCommandV1 struct {
 }
 
 // The name of the join command in the log
-func (c *JoinCommandV1) CommandName() string {
+func (c *JoinCommand) CommandName() string {
 	return "etcd:join"
 }
 
-func (c *JoinCommandV1) updatePeerURL(ps *PeerServer) error {
-	log.Debugf("Update peer URL of %v to %v", c.Name, c.RaftURL)
-	if err := ps.registry.UpdatePeerURL(c.Name, c.RaftURL); err != nil {
-		log.Debugf("Error while updating in registry: %s (%v)", c.Name, err)
-		return err
+// Apply attempts to join a machine to the cluster.
+func (c *JoinCommand) Apply(context raft.Context) (interface{}, error) {
+	index, err := applyJoin(c, context)
+	if err != nil {
+		return nil, err
 	}
-	// Flush commit index, so raft will replay to here when restarted
-	ps.raftServer.FlushCommitIndex()
-	return nil
+
+	b := make([]byte, 8)
+	binary.PutUvarint(b, index)
+	return b, nil
 }
 
-// Join a server to the cluster
-func (c *JoinCommandV1) Apply(context raft.Context) (interface{}, error) {
-	ps, _ := context.Server().Context().(*PeerServer)
+func (c *JoinCommand) NodeName() string {
+	return c.Name
+}
 
-	b := make([]byte, 8)
-	binary.PutUvarint(b, context.CommitIndex())
+// applyJoin attempts to join a machine to the cluster.
+func applyJoin(c *JoinCommand, context raft.Context) (uint64, error) {
+	ps, _ := context.Server().Context().(*PeerServer)
+	commitIndex := context.CommitIndex()
 
 	// Make sure we're not getting a cached value from the registry.
 	ps.registry.Invalidate(c.Name)
@@ -56,11 +57,11 @@ func (c *JoinCommandV1) Apply(context raft.Context) (interface{}, error) {
 		// update its information.
 		if peerURL != c.RaftURL {
 			log.Infof("Rejoin with %v instead of %v from %v", c.RaftURL, peerURL, c.Name)
-			if err := c.updatePeerURL(ps); err != nil {
-				return []byte{0}, err
+			if err := updatePeerURL(c, ps); err != nil {
+				return 0, err
 			}
 		}
-		return b, nil
+		return commitIndex, nil
 	}
 
 	// Check if the join command adds an instance that collides with existing one on peer URL.
@@ -68,21 +69,23 @@ func (c *JoinCommandV1) Apply(context raft.Context) (interface{}, error) {
 	for _, peerURL := range peerURLs {
 		if peerURL == c.RaftURL {
 			log.Warnf("%v tries to join the cluster with existing URL %v", c.Name, c.EtcdURL)
-			return []byte{0}, etcdErr.NewError(etcdErr.EcodeExistingPeerAddr, c.EtcdURL, context.CommitIndex())
+			return 0, etcdErr.NewError(etcdErr.EcodeExistingPeerAddr, c.EtcdURL, context.CommitIndex())
 		}
 	}
 
 	// Check peer number in the cluster
-	if ps.registry.PeerCount() >= ps.ClusterConfig().ActiveSize {
+	if ps.registry.Count() >= ps.ClusterConfig().ActiveSize {
 		log.Debug("Reject join request from ", c.Name)
-		return []byte{0}, etcdErr.NewError(etcdErr.EcodeNoMorePeer, "", context.CommitIndex())
+		return 0, etcdErr.NewError(etcdErr.EcodeNoMorePeer, "", context.CommitIndex())
 	}
 
 	// Add to shared peer registry.
-	ps.registry.RegisterPeer(c.Name, c.RaftURL, c.EtcdURL)
+	ps.registry.Register(c.Name, c.RaftURL, c.EtcdURL)
 
 	// Add peer in raft
-	err := context.Server().AddPeer(c.Name, "")
+	if err := context.Server().AddPeer(c.Name, ""); err != nil {
+		return 0, err
+	}
 
 	// Add peer stats
 	if c.Name != ps.RaftServer().Name() {
@@ -90,30 +93,12 @@ func (c *JoinCommandV1) Apply(context raft.Context) (interface{}, error) {
 		ps.followersStats.Followers[c.Name].Latency.Minimum = 1 << 63
 	}
 
-	return b, err
-}
-
-func (c *JoinCommandV1) NodeName() string {
-	return c.Name
+	return commitIndex, nil
 }
 
-// JoinCommandV2 represents a request to join the cluster.
-type JoinCommandV2 struct {
-	MinVersion int    `json:"minVersion"`
-	MaxVersion int    `json:"maxVersion"`
-	Name       string `json:"name"`
-	PeerURL    string `json:"peerURL"`
-	ClientURL  string `json:"clientURL"`
-}
-
-// CommandName returns the name of the command in the Raft log.
-func (c *JoinCommandV2) CommandName() string {
-	return "etcd:v2:join"
-}
-
-func (c *JoinCommandV2) updatePeerURL(ps *PeerServer) error {
-	log.Debugf("Update peer URL of %v to %v", c.Name, c.PeerURL)
-	if err := ps.registry.UpdatePeerURL(c.Name, c.PeerURL); err != nil {
+func updatePeerURL(c *JoinCommand, ps *PeerServer) error {
+	log.Debugf("Update peer URL of %v to %v", c.Name, c.RaftURL)
+	if err := ps.registry.UpdatePeerURL(c.Name, c.RaftURL); err != nil {
 		log.Debugf("Error while updating in registry: %s (%v)", c.Name, err)
 		return err
 	}
@@ -121,76 +106,3 @@ func (c *JoinCommandV2) updatePeerURL(ps *PeerServer) error {
 	ps.raftServer.FlushCommitIndex()
 	return nil
 }
-
-// Apply attempts to join a machine to the cluster.
-func (c *JoinCommandV2) Apply(context raft.Context) (interface{}, error) {
-	ps, _ := context.Server().Context().(*PeerServer)
-	var msg = joinMessageV2{
-		Mode:        PeerMode,
-		CommitIndex: context.CommitIndex(),
-	}
-
-	// Make sure we're not getting a cached value from the registry.
-	ps.registry.Invalidate(c.Name)
-
-	// Check if the join command is from a previous peer, who lost all its previous log.
-	if peerURL, ok := ps.registry.PeerURL(c.Name); ok {
-		// If previous node restarts with different peer URL,
-		// update its information.
-		if peerURL != c.PeerURL {
-			log.Infof("Rejoin with %v instead of %v from %v", c.PeerURL, peerURL, c.Name)
-			if err := c.updatePeerURL(ps); err != nil {
-				return []byte{0}, err
-			}
-		}
-		return json.Marshal(msg)
-	}
-
-	// Check if the join command adds an instance that collides with existing one on peer URL.
-	peerURLs := ps.registry.PeerURLs(ps.raftServer.Leader(), c.Name)
-	for _, peerURL := range peerURLs {
-		if peerURL == c.PeerURL {
-			log.Warnf("%v tries to join the cluster with existing URL %v", c.Name, c.PeerURL)
-			return []byte{0}, etcdErr.NewError(etcdErr.EcodeExistingPeerAddr, c.PeerURL, context.CommitIndex())
-		}
-	}
-
-	// Check peer number in the cluster.
-	if ps.registry.PeerCount() >= ps.ClusterConfig().ActiveSize {
-		log.Debug("Join as standby ", c.Name)
-		ps.registry.RegisterStandby(c.Name, c.PeerURL, c.ClientURL)
-		msg.Mode = StandbyMode
-		return json.Marshal(msg)
-	}
-
-	// Remove it as a standby if it is one.
-	if ps.registry.StandbyExists(c.Name) {
-		ps.registry.UnregisterStandby(c.Name)
-	}
-
-	// Add to shared peer registry.
-	ps.registry.RegisterPeer(c.Name, c.PeerURL, c.ClientURL)
-
-	// Add peer in raft
-	if err := context.Server().AddPeer(c.Name, ""); err != nil {
-		b, _ := json.Marshal(msg)
-		return b, err
-	}
-
-	// Add peer stats
-	if c.Name != ps.RaftServer().Name() {
-		ps.followersStats.Followers[c.Name] = &raftFollowerStats{}
-		ps.followersStats.Followers[c.Name].Latency.Minimum = 1 << 63
-	}
-
-	return json.Marshal(msg)
-}
-
-func (c *JoinCommandV2) NodeName() string {
-	return c.Name
-}
-
-type joinMessageV2 struct {
-	CommitIndex uint64 `json:"commitIndex"`
-	Mode        Mode   `json:"mode"`
-}

server/peer_server.go

@@ -2,6 +2,7 @@ package server
 
 import (
 	"bytes"
+	"encoding/binary"
 	"encoding/json"
 	"fmt"
 	"io/ioutil"
@@ -31,8 +32,8 @@ const (
 	ThresholdMonitorTimeout = 5 * time.Second
 
 	// ActiveMonitorTimeout is the time between checks on the active size of
-	// the cluster. If the active size is different than the actual size then
-	// etcd attempts to promote/demote to bring it to the correct number.
+	// the cluster. If the active size is bigger than the actual size then
+	// etcd attempts to demote to bring it to the correct number.
 	ActiveMonitorTimeout = 1 * time.Second
 
 	// PeerActivityMonitorTimeout is the time between checks for dead nodes in
@@ -40,11 +41,6 @@ const (
 	PeerActivityMonitorTimeout = 1 * time.Second
 )
 
-const (
-	peerModeFlag    = 0
-	standbyModeFlag = 1
-)
-
 type PeerServerConfig struct {
 	Name          string
 	Scheme        string
@@ -65,14 +61,10 @@ type PeerServer struct {
 	registry       *Registry
 	store          store.Store
 	snapConf       *snapshotConf
-	mode           Mode
 
 	closeChan            chan bool
 	timeoutThresholdChan chan interface{}
 
-	standbyPeerURL   string
-	standbyClientURL string
-
 	metrics *metrics.Bucket
 	sync.Mutex
 }
@@ -128,29 +120,6 @@ func (s *PeerServer) SetRaftServer(raftServer raft.Server) {
 	s.raftServer = raftServer
 }
 
-// Mode retrieves the current mode of the server.
-func (s *PeerServer) Mode() Mode {
-	return s.mode
-}
-
-// SetMode updates the current mode of the server.
-// Switching to a peer mode will start the Raft server.
-// Switching to a standby mode will stop the Raft server.
-func (s *PeerServer) setMode(mode Mode) {
-	s.mode = mode
-
-	switch mode {
-	case PeerMode:
-		if !s.raftServer.Running() {
-			s.raftServer.Start()
-		}
-	case StandbyMode:
-		if s.raftServer.Running() {
-			s.raftServer.Stop()
-		}
-	}
-}
-
 // ClusterConfig retrieves the current cluster configuration.
 func (s *PeerServer) ClusterConfig() *ClusterConfig {
 	return s.clusterConfig
@@ -326,7 +295,6 @@ func (s *PeerServer) HTTPHandler() http.Handler {
 	router.HandleFunc("/version/{version:[0-9]+}/check", s.VersionCheckHttpHandler)
 	router.HandleFunc("/upgrade", s.UpgradeHttpHandler)
 	router.HandleFunc("/join", s.JoinHttpHandler)
-	router.HandleFunc("/promote", s.PromoteHttpHandler).Methods("POST")
 	router.HandleFunc("/remove/{name:.+}", s.RemoveHttpHandler)
 	router.HandleFunc("/vote", s.VoteHttpHandler)
 	router.HandleFunc("/log", s.GetLogHttpHandler)
@@ -339,8 +307,6 @@ func (s *PeerServer) HTTPHandler() http.Handler {
 	router.HandleFunc("/v2/admin/config", s.setClusterConfigHttpHandler).Methods("PUT")
 	router.HandleFunc("/v2/admin/machines", s.getMachinesHttpHandler).Methods("GET")
 	router.HandleFunc("/v2/admin/machines/{name}", s.getMachineHttpHandler).Methods("GET")
-	router.HandleFunc("/v2/admin/machines/{name}", s.addMachineHttpHandler).Methods("PUT")
-	router.HandleFunc("/v2/admin/machines/{name}", s.removeMachineHttpHandler).Methods("DELETE")
 
 	return router
 }
@@ -359,15 +325,14 @@ func (s *PeerServer) startAsLeader() {
 	s.raftServer.Start()
 	// leader need to join self as a peer
 	for {
-		c := &JoinCommandV1{
+		c := &JoinCommand{
 			MinVersion: store.MinVersion(),
 			MaxVersion: store.MaxVersion(),
 			Name:       s.raftServer.Name(),
 			RaftURL:    s.Config.URL,
 			EtcdURL:    s.server.URL(),
 		}
-		_, err := s.raftServer.Do(c)
-		if err == nil {
+		if _, err := s.raftServer.Do(c); err == nil {
 			break
 		}
 	}
@@ -548,16 +513,16 @@ func (s *PeerServer) joinByPeer(server raft.Server, peer string, scheme string)
 	}
 
 	var b bytes.Buffer
-	c := &JoinCommandV2{
+	c := &JoinCommand{
 		MinVersion: store.MinVersion(),
 		MaxVersion: store.MaxVersion(),
 		Name:       server.Name(),
-		PeerURL:    s.Config.URL,
-		ClientURL:  s.server.URL(),
+		RaftURL:    s.Config.URL,
+		EtcdURL:    s.server.URL(),
 	}
 	json.NewEncoder(&b).Encode(c)
 
-	joinURL := url.URL{Host: peer, Scheme: scheme, Path: "/v2/admin/machines/" + server.Name()}
+	joinURL := url.URL{Host: peer, Scheme: scheme, Path: "/join"}
 	log.Infof("Send Join Request to %s", joinURL.String())
 
 	req, _ := http.NewRequest("PUT", joinURL.String(), &b)
@@ -572,30 +537,19 @@ func (s *PeerServer) joinByPeer(server raft.Server, peer string, scheme string)
 
 			log.Infof("»»»» %d", resp.StatusCode)
 			if resp.StatusCode == http.StatusOK {
-				var msg joinMessageV2
-				if err := json.NewDecoder(resp.Body).Decode(&msg); err != nil {
-					log.Debugf("Error reading join response: %v", err)
-					return err
-				}
-				s.joinIndex = msg.CommitIndex
-				s.setMode(msg.Mode)
-
-				if msg.Mode == StandbyMode {
-					s.standbyClientURL = resp.Header.Get("X-Leader-Client-URL")
-					s.standbyPeerURL = resp.Header.Get("X-Leader-Peer-URL")
-				}
-
+				b, _ := ioutil.ReadAll(resp.Body)
+				s.joinIndex, _ = binary.Uvarint(b)
 				return nil
 			}
 			if resp.StatusCode == http.StatusTemporaryRedirect {
 				address := resp.Header.Get("Location")
 				log.Debugf("Send Join Request to %s", address)
-				c := &JoinCommandV2{
+				c := &JoinCommand{
 					MinVersion: store.MinVersion(),
 					MaxVersion: store.MaxVersion(),
 					Name:       server.Name(),
-					PeerURL:    s.Config.URL,
-					ClientURL:  s.server.URL(),
+					RaftURL:    s.Config.URL,
+					EtcdURL:    s.server.URL(),
 				}
 				json.NewEncoder(&b).Encode(c)
 				resp, _, err = t.Put(address, &b)
@@ -755,49 +709,21 @@ func (s *PeerServer) monitorActiveSize(closeChan chan bool) {
 
 		// Retrieve target active size and actual active size.
 		activeSize := s.ClusterConfig().ActiveSize
-		peerCount := s.registry.PeerCount()
-		standbys := s.registry.Standbys()
-		peers := s.registry.Peers()
+		peerCount := s.registry.Count()
+		peers := s.registry.Names()
 		if index := sort.SearchStrings(peers, s.Config.Name); index < len(peers) && peers[index] == s.Config.Name {
 			peers = append(peers[:index], peers[index+1:]...)
 		}
 
-		// If we have more active nodes than we should then demote.
+		// If we have more active nodes than we should then remove.
 		if peerCount > activeSize {
 			peer := peers[rand.Intn(len(peers))]
-			log.Infof("%s: demoting: %v", s.Config.Name, peer)
-			if _, err := s.raftServer.Do(&DemoteCommand{Name: peer}); err != nil {
-				log.Infof("%s: warning: demotion error: %v", s.Config.Name, err)
+			log.Infof("%s: removing: %v", s.Config.Name, peer)
+			if _, err := s.raftServer.Do(&RemoveCommand{Name: peer}); err != nil {
+				log.Infof("%s: warning: remove error: %v", s.Config.Name, err)
 			}
 			continue
 		}
-
-		// If we don't have enough active nodes then try to promote a standby.
-		if peerCount < activeSize && len(standbys) > 0 {
-		loop:
-			for _, i := range rand.Perm(len(standbys)) {
-				standby := standbys[i]
-				standbyPeerURL, _ := s.registry.StandbyPeerURL(standby)
-				log.Infof("%s: attempting to promote: %v (%s)", s.Config.Name, standby, standbyPeerURL)
-
-				// Notify standby to promote itself.
-				client := &http.Client{
-					Transport: &http.Transport{
-						DisableKeepAlives:     false,
-						ResponseHeaderTimeout: ActiveMonitorTimeout,
-					},
-				}
-				resp, err := client.Post(fmt.Sprintf("%s/promote", standbyPeerURL), "application/json", nil)
-				if err != nil {
-					log.Infof("%s: warning: promotion error: %v", s.Config.Name, err)
-					continue
-				} else if resp.StatusCode != http.StatusOK {
-					log.Infof("%s: warning: promotion failure: %v", s.Config.Name, resp.StatusCode)
-					continue
-				}
-				break loop
-			}
-		}
 	}
 }
 
@@ -823,8 +749,8 @@ func (s *PeerServer) monitorPeerActivity(closeChan chan bool) {
 			// If the last response from the peer is longer than the promote delay
 			// then automatically demote the peer.
 			if !peer.LastActivity().IsZero() && now.Sub(peer.LastActivity()) > promoteDelay {
-				log.Infof("%s: demoting node: %v; last activity %v ago", s.Config.Name, peer.Name, now.Sub(peer.LastActivity()))
-				if _, err := s.raftServer.Do(&DemoteCommand{Name: peer.Name}); err != nil {
+				log.Infof("%s: removing node: %v; last activity %v ago", s.Config.Name, peer.Name, now.Sub(peer.LastActivity()))
+				if _, err := s.raftServer.Do(&RemoveCommand{Name: peer.Name}); err != nil {
 					log.Infof("%s: warning: autodemotion error: %v", s.Config.Name, err)
 				}
 				continue
@@ -832,15 +758,3 @@ func (s *PeerServer) monitorPeerActivity(closeChan chan bool) {
 		}
 	}
 }
-
-// Mode represents whether the server is an active peer or if the server is
-// simply acting as a standby.
-type Mode string
-
-const (
-	// PeerMode is when the server is an active node in Raft.
-	PeerMode = Mode("peer")
-
-	// StandbyMode is when the server is an inactive, request-forwarding node.
-	StandbyMode = Mode("standby")
-)

server/peer_server_handlers.go

@@ -3,7 +3,6 @@ package server
 import (
 	"encoding/json"
 	"net/http"
-	"net/url"
 	"strconv"
 	"time"
 
@@ -150,7 +149,7 @@ func (ps *PeerServer) EtcdURLHttpHandler(w http.ResponseWriter, req *http.Reques
 
 // Response to the join request
 func (ps *PeerServer) JoinHttpHandler(w http.ResponseWriter, req *http.Request) {
-	command := &JoinCommandV1{}
+	command := &JoinCommand{}
 	if err := uhttp.DecodeJsonRequest(req, command); err != nil {
 		w.WriteHeader(http.StatusInternalServerError)
 		return
@@ -170,25 +169,6 @@ func (ps *PeerServer) JoinHttpHandler(w http.ResponseWriter, req *http.Request)
 	}
 }
 
-// Attempt to rejoin the cluster as a peer.
-func (ps *PeerServer) PromoteHttpHandler(w http.ResponseWriter, req *http.Request) {
-	log.Infof("%s attempting to promote in cluster: %s", ps.Config.Name, ps.standbyPeerURL)
-	url, err := url.Parse(ps.standbyPeerURL)
-	if err != nil {
-		w.WriteHeader(http.StatusInternalServerError)
-		return
-	}
-
-	err = ps.joinByPeer(ps.raftServer, url.Host, ps.Config.Scheme)
-	if err != nil {
-		log.Infof("%s error while promoting: %v", ps.Config.Name, err)
-		w.WriteHeader(http.StatusInternalServerError)
-		return
-	}
-	log.Infof("%s promoted in the cluster", ps.Config.Name)
-	w.WriteHeader(http.StatusOK)
-}
-
 // Response to remove request
 func (ps *PeerServer) RemoveHttpHandler(w http.ResponseWriter, req *http.Request) {
 	if req.Method != "DELETE" {
@@ -197,7 +177,7 @@ func (ps *PeerServer) RemoveHttpHandler(w http.ResponseWriter, req *http.Request
 	}
 
 	vars := mux.Vars(req)
-	command := &RemoveCommandV1{
+	command := &RemoveCommand{
 		Name: vars["name"],
 	}
 
@@ -243,10 +223,7 @@ func (ps *PeerServer) setClusterConfigHttpHandler(w http.ResponseWriter, req *ht
 // Retrieves a list of peers and standbys.
 func (ps *PeerServer) getMachinesHttpHandler(w http.ResponseWriter, req *http.Request) {
 	machines := make([]*machineMessage, 0)
-	for _, name := range ps.registry.Peers() {
-		machines = append(machines, ps.getMachineMessage(name))
-	}
-	for _, name := range ps.registry.Standbys() {
+	for _, name := range ps.registry.Names() {
 		machines = append(machines, ps.getMachineMessage(name))
 	}
 	json.NewEncoder(w).Encode(&machines)
@@ -259,56 +236,17 @@ func (ps *PeerServer) getMachineHttpHandler(w http.ResponseWriter, req *http.Req
 }
 
 func (ps *PeerServer) getMachineMessage(name string) *machineMessage {
-	if ps.registry.PeerExists(name) {
-		clientURL, _ := ps.registry.ClientURL(name)
-		peerURL, _ := ps.registry.PeerURL(name)
-		return &machineMessage{
-			Name:      name,
-			Mode:      PeerMode,
-			ClientURL: clientURL,
-			PeerURL:   peerURL,
-		}
+	if !ps.registry.Exists(name) {
+		return nil
 	}
 
-	if ps.registry.StandbyExists(name) {
-		clientURL, _ := ps.registry.StandbyClientURL(name)
-		peerURL, _ := ps.registry.StandbyPeerURL(name)
-		return &machineMessage{
-			Name:      name,
-			Mode:      StandbyMode,
-			ClientURL: clientURL,
-			PeerURL:   peerURL,
-		}
+	clientURL, _ := ps.registry.ClientURL(name)
+	peerURL, _ := ps.registry.PeerURL(name)
+	return &machineMessage{
+		Name:      name,
+		ClientURL: clientURL,
+		PeerURL:   peerURL,
 	}
-
-	return nil
-}
-
-// Adds a machine to the cluster.
-func (ps *PeerServer) addMachineHttpHandler(w http.ResponseWriter, req *http.Request) {
-	c := &JoinCommandV2{}
-	if err := uhttp.DecodeJsonRequest(req, c); err != nil {
-		w.WriteHeader(http.StatusInternalServerError)
-		return
-	}
-
-	log.Debugf("Receive Join Request (v2) from %s", c.Name)
-	if err := ps.server.Dispatch(c, w, req); err != nil {
-		if etcdErr, ok := err.(*etcdErr.Error); ok {
-			log.Debug("Return error: ", (*etcdErr).Error())
-			etcdErr.Write(w)
-		} else {
-			http.Error(w, err.Error(), http.StatusInternalServerError)
-		}
-	}
-}
-
-// Removes a machine from the cluster.
-func (ps *PeerServer) removeMachineHttpHandler(w http.ResponseWriter, req *http.Request) {
-	vars := mux.Vars(req)
-	c := &RemoveCommandV2{Name: vars["name"]}
-	log.Debugf("[recv] Remove Request [%s]", c.Name)
-	ps.server.Dispatch(c, w, req)
 }
 
 // Response to the name request
@@ -360,7 +298,6 @@ func (ps *PeerServer) UpgradeHttpHandler(w http.ResponseWriter, req *http.Reques
 // machineMessage represents information about a peer or standby in the registry.
 type machineMessage struct {
 	Name      string `json:"name"`
-	Mode      Mode   `json:"mode"`
 	ClientURL string `json:"clientURL"`
 	PeerURL   string `json:"peerURL"`
 }

server/registry.go

@@ -14,17 +14,13 @@ import (
 )
 
 // The location of the peer URL data.
-const RegistryPeerKey = "/_etcd/machines"
-
-// The location of the standby URL data.
-const RegistryStandbyKey = "/_etcd/standbys"
+const RegistryKey = "/_etcd/machines"
 
 // The Registry stores URL information for nodes.
 type Registry struct {
 	sync.Mutex
-	store    store.Store
-	peers    map[string]*node
-	standbys map[string]*node
+	store store.Store
+	peers map[string]*node
 }
 
 // The internal storage format of the registry.
@@ -37,14 +33,13 @@ type node struct {
 // Creates a new Registry.
 func NewRegistry(s store.Store) *Registry {
 	return &Registry{
-		store:    s,
-		peers:    make(map[string]*node),
-		standbys: make(map[string]*node),
+		store: s,
+		peers: make(map[string]*node),
 	}
 }
 
-// Peers returns a list of cached peer names.
-func (r *Registry) Peers() []string {
+// Names returns a list of cached peer names.
+func (r *Registry) Names() []string {
 	r.Lock()
 	defer r.Unlock()
 
@@ -56,120 +51,43 @@ func (r *Registry) Peers() []string {
 	return names
 }
 
-// Standbys returns a list of cached standby names.
-func (r *Registry) Standbys() []string {
-	r.Lock()
-	defer r.Unlock()
-
-	names := make([]string, 0, len(r.standbys))
-	for name := range r.standbys {
-		names = append(names, name)
-	}
-	sort.Sort(sort.StringSlice(names))
-	return names
-}
-
-// RegisterPeer adds a peer to the registry.
-func (r *Registry) RegisterPeer(name string, peerURL string, machURL string) error {
-	if err := r.register(RegistryPeerKey, name, peerURL, machURL); err != nil {
-		return err
-	}
-
-	r.Lock()
-	defer r.Unlock()
-	r.peers[name] = r.load(RegistryPeerKey, name)
-	return nil
-}
-
-// RegisterStandby adds a standby to the registry.
-func (r *Registry) RegisterStandby(name string, peerURL string, machURL string) error {
-	if err := r.register(RegistryStandbyKey, name, peerURL, machURL); err != nil {
-		return err
-	}
-
-	r.Lock()
-	defer r.Unlock()
-	r.standbys[name] = r.load(RegistryStandbyKey, name)
-	return nil
-}
-
-func (r *Registry) register(key, name string, peerURL string, machURL string) error {
+// Register adds a peer to the registry.
+func (r *Registry) Register(name string, peerURL string, machURL string) error {
 	// Write data to store.
 	v := url.Values{}
 	v.Set("raft", peerURL)
 	v.Set("etcd", machURL)
-	_, err := r.store.Create(path.Join(key, name), false, v.Encode(), false, store.Permanent)
 	log.Debugf("Register: %s", name)
-	return err
-}
+	if _, err := r.store.Create(path.Join(RegistryKey, name), false, v.Encode(), false, store.Permanent); err != nil {
+		return err
+	}
 
-// UpdatePeerURL updates peer URL in registry
-func (r *Registry) UpdatePeerURL(name string, peerURL string) error {
 	r.Lock()
 	defer r.Unlock()
-
-	machURL, _ := r.clientURL(RegistryPeerKey, name)
-	// Write data to store.
-	key := path.Join(RegistryPeerKey, name)
-	v := url.Values{}
-	v.Set("raft", peerURL)
-	v.Set("etcd", machURL)
-	_, err := r.store.Update(key, v.Encode(), store.Permanent)
-
-	// Invalidate outdated cache.
-	r.invalidate(name)
-	log.Debugf("Update PeerURL: %s", name)
-	return err
-}
-
-// UnregisterPeer removes a peer from the registry.
-func (r *Registry) UnregisterPeer(name string) error {
-	return r.unregister(RegistryPeerKey, name)
-}
-
-// UnregisterStandby removes a standby from the registry.
-func (r *Registry) UnregisterStandby(name string) error {
-	return r.unregister(RegistryStandbyKey, name)
+	r.peers[name] = r.load(RegistryKey, name)
+	return nil
 }
 
-func (r *Registry) unregister(key, name string) error {
+// Unregister removes a peer from the registry.
+func (r *Registry) Unregister(name string) error {
 	// Remove the key from the store.
-	_, err := r.store.Delete(path.Join(key, name), false, false)
 	log.Debugf("Unregister: %s", name)
+	_, err := r.store.Delete(path.Join(RegistryKey, name), false, false)
 	return err
 }
 
-// PeerCount returns the number of peers in the cluster.
-func (r *Registry) PeerCount() int {
-	return r.count(RegistryPeerKey)
-}
-
-// StandbyCount returns the number of standbys in the cluster.
-func (r *Registry) StandbyCount() int {
-	return r.count(RegistryStandbyKey)
-}
-
-// Returns the number of nodes in the cluster.
-func (r *Registry) count(key string) int {
-	e, err := r.store.Get(key, false, false)
+// Count returns the number of peers in the cluster.
+func (r *Registry) Count() int {
+	e, err := r.store.Get(RegistryKey, false, false)
 	if err != nil {
 		return 0
 	}
 	return len(e.Node.Nodes)
 }
 
-// PeerExists checks if a peer with the given name exists.
-func (r *Registry) PeerExists(name string) bool {
-	return r.exists(RegistryPeerKey, name)
-}
-
-// StandbyExists checks if a standby with the given name exists.
-func (r *Registry) StandbyExists(name string) bool {
-	return r.exists(RegistryStandbyKey, name)
-}
-
-func (r *Registry) exists(key, name string) bool {
-	e, err := r.store.Get(path.Join(key, name), false, false)
+// Exists checks if a peer with the given name exists.
+func (r *Registry) Exists(name string) bool {
+	e, err := r.store.Get(path.Join(RegistryKey, name), false, false)
 	if err != nil {
 		return false
 	}
@@ -180,18 +98,18 @@ func (r *Registry) exists(key, name string) bool {
 func (r *Registry) ClientURL(name string) (string, bool) {
 	r.Lock()
 	defer r.Unlock()
-	return r.clientURL(RegistryPeerKey, name)
+	return r.clientURL(RegistryKey, name)
 }
 
 func (r *Registry) clientURL(key, name string) (string, bool) {
 	if r.peers[name] == nil {
-		if node := r.load(key, name); node != nil {
-			r.peers[name] = node
+		if peer := r.load(key, name); peer != nil {
+			r.peers[name] = peer
 		}
 	}
 
-	if node := r.peers[name]; node != nil {
-		return node.url, true
+	if peer := r.peers[name]; peer != nil {
+		return peer.url, true
 	}
 
 	return "", false
@@ -213,69 +131,50 @@ func (r *Registry) PeerHost(name string) (string, bool) {
 func (r *Registry) PeerURL(name string) (string, bool) {
 	r.Lock()
 	defer r.Unlock()
-	return r.peerURL(RegistryPeerKey, name)
+	return r.peerURL(RegistryKey, name)
 }
 
 func (r *Registry) peerURL(key, name string) (string, bool) {
 	if r.peers[name] == nil {
-		if node := r.load(key, name); node != nil {
-			r.peers[name] = node
+		if peer := r.load(key, name); peer != nil {
+			r.peers[name] = peer
 		}
 	}
 
-	if node := r.peers[name]; node != nil {
-		return node.peerURL, true
+	if peer := r.peers[name]; peer != nil {
+		return peer.peerURL, true
 	}
 
 	return "", false
 }
 
-// Retrieves the client URL for a given standby by name.
-func (r *Registry) StandbyClientURL(name string) (string, bool) {
-	r.Lock()
-	defer r.Unlock()
-	return r.standbyClientURL(RegistryStandbyKey, name)
-}
-
-func (r *Registry) standbyClientURL(key, name string) (string, bool) {
-	if r.standbys[name] == nil {
-		if node := r.load(key, name); node != nil {
-			r.standbys[name] = node
-		}
-	}
-	if node := r.standbys[name]; node != nil {
-		return node.url, true
+// UpdatePeerURL updates peer URL in registry
+func (r *Registry) UpdatePeerURL(name string, peerURL string) error {
+	machURL, _ := r.clientURL(RegistryKey, name)
+	// Write data to store.
+	v := url.Values{}
+	v.Set("raft", peerURL)
+	v.Set("etcd", machURL)
+	log.Debugf("Update PeerURL: %s", name)
+	if _, err := r.store.Update(path.Join(RegistryKey, name), v.Encode(), store.Permanent); err != nil {
+		return err
 	}
-	return "", false
-}
 
-// Retrieves the peer URL for a given standby by name.
-func (r *Registry) StandbyPeerURL(name string) (string, bool) {
 	r.Lock()
 	defer r.Unlock()
-	return r.standbyPeerURL(RegistryStandbyKey, name)
-}
-
-func (r *Registry) standbyPeerURL(key, name string) (string, bool) {
-	if r.standbys[name] == nil {
-		if node := r.load(key, name); node != nil {
-			r.standbys[name] = node
-		}
-	}
-	if node := r.standbys[name]; node != nil {
-		return node.peerURL, true
-	}
-	return "", false
+	// Invalidate outdated cache.
+	r.invalidate(name)
+	return nil
 }
 
 // Retrieves the Client URLs for all nodes.
 func (r *Registry) ClientURLs(leaderName, selfName string) []string {
-	return r.urls(RegistryPeerKey, leaderName, selfName, r.clientURL)
+	return r.urls(RegistryKey, leaderName, selfName, r.clientURL)
 }
 
 // Retrieves the Peer URLs for all nodes.
 func (r *Registry) PeerURLs(leaderName, selfName string) []string {
-	return r.urls(RegistryPeerKey, leaderName, selfName, r.peerURL)
+	return r.urls(RegistryKey, leaderName, selfName, r.peerURL)
 }
 
 // Retrieves the URLs for all nodes using url function.
@@ -313,7 +212,6 @@ func (r *Registry) Invalidate(name string) {
 
 func (r *Registry) invalidate(name string) {
 	delete(r.peers, name)
-	delete(r.standbys, name)
 }
 
 // Loads the given node by name from the store into the cache.

server/remove_command.go

@@ -2,7 +2,6 @@ package server
 
 import (
 	"encoding/binary"
-	"encoding/json"
 	"os"
 
 	"github.com/coreos/etcd/log"
@@ -10,107 +9,51 @@ import (
 )
 
 func init() {
-	raft.RegisterCommand(&RemoveCommandV1{})
-	raft.RegisterCommand(&RemoveCommandV2{})
+	raft.RegisterCommand(&RemoveCommand{})
 }
 
-// The RemoveCommandV1 removes a server from the cluster.
-type RemoveCommandV1 struct {
+// The RemoveCommand removes a server from the cluster.
+type RemoveCommand struct {
 	Name string `json:"name"`
 }
 
 // The name of the remove command in the log
-func (c *RemoveCommandV1) CommandName() string {
+func (c *RemoveCommand) CommandName() string {
 	return "etcd:remove"
 }
 
 // Remove a server from the cluster
-func (c *RemoveCommandV1) Apply(context raft.Context) (interface{}, error) {
-	ps, _ := context.Server().Context().(*PeerServer)
-
-	// If this is a standby then remove it and exit.
-	if ps.registry.StandbyExists(c.Name) {
-		return []byte{0}, ps.registry.UnregisterStandby(c.Name)
-	}
-
-	// Remove node from the shared registry.
-	err := ps.registry.UnregisterPeer(c.Name)
-
-	// Delete from stats
-	delete(ps.followersStats.Followers, c.Name)
-
+func (c *RemoveCommand) Apply(context raft.Context) (interface{}, error) {
+	index, err := applyRemove(c, context)
 	if err != nil {
-		log.Debugf("Error while unregistering: %s (%v)", c.Name, err)
-		return []byte{0}, err
-	}
-
-	// Remove peer in raft
-	err = context.Server().RemovePeer(c.Name)
-	if err != nil {
-		log.Debugf("Unable to remove peer: %s (%v)", c.Name, err)
-		return []byte{0}, err
-	}
-
-	if c.Name == context.Server().Name() {
-		// the removed node is this node
-
-		// if the node is not replaying the previous logs
-		// and the node has sent out a join request in this
-		// start. It is sure that this node received a new remove
-		// command and need to be removed
-		if context.CommitIndex() > ps.joinIndex && ps.joinIndex != 0 {
-			log.Debugf("server [%s] is removed", context.Server().Name())
-			os.Exit(0)
-		} else {
-			// else ignore remove
-			log.Debugf("ignore previous remove command.")
-		}
+		return nil, err
 	}
 
 	b := make([]byte, 8)
-	binary.PutUvarint(b, context.CommitIndex())
-
-	return b, err
-}
-
-// RemoveCommandV2 represents a command to remove a machine from the server.
-type RemoveCommandV2 struct {
-	Name string `json:"name"`
-}
-
-// CommandName returns the name of the command.
-func (c *RemoveCommandV2) CommandName() string {
-	return "etcd:v2:remove"
+	binary.PutUvarint(b, index)
+	return b, nil
 }
 
-// Apply removes the given machine from the cluster.
-func (c *RemoveCommandV2) Apply(context raft.Context) (interface{}, error) {
+// applyRemove removes the given machine from the cluster.
+func applyRemove(c *RemoveCommand, context raft.Context) (uint64, error) {
 	ps, _ := context.Server().Context().(*PeerServer)
-	ret, _ := json.Marshal(removeMessageV2{CommitIndex: context.CommitIndex()})
-
-	// If this is a standby then remove it and exit.
-	if ps.registry.StandbyExists(c.Name) {
-		if err := ps.registry.UnregisterStandby(c.Name); err != nil {
-			return nil, err
-		}
-		return ret, nil
-	}
+	commitIndex := context.CommitIndex()
 
 	// Remove node from the shared registry.
-	err := ps.registry.UnregisterPeer(c.Name)
+	err := ps.registry.Unregister(c.Name)
 
 	// Delete from stats
 	delete(ps.followersStats.Followers, c.Name)
 
 	if err != nil {
 		log.Debugf("Error while unregistering: %s (%v)", c.Name, err)
-		return nil, err
+		return 0, err
 	}
 
 	// Remove peer in raft
 	if err := context.Server().RemovePeer(c.Name); err != nil {
 		log.Debugf("Unable to remove peer: %s (%v)", c.Name, err)
-		return nil, err
+		return 0, err
 	}
 
 	if c.Name == context.Server().Name() {
@@ -128,9 +71,5 @@ func (c *RemoveCommandV2) Apply(context raft.Context) (interface{}, error) {
 			log.Debugf("ignore previous remove command.")
 		}
 	}
-	return ret, nil
-}
-
-type removeMessageV2 struct {
-	CommitIndex uint64 `json:"commitIndex"`
+	return commitIndex, nil
 }

server/server.go

@@ -176,17 +176,6 @@ func (s *Server) handleFunc(r *mux.Router, path string, f func(http.ResponseWrit
 		// Log request.
 		log.Debugf("[recv] %s %s %s [%s]", req.Method, s.URL(), req.URL.Path, req.RemoteAddr)
 
-		// Forward request along if the server is a standby.
-		if s.peerServer.Mode() == StandbyMode {
-			if s.peerServer.standbyClientURL == "" {
-				w.Header().Set("Content-Type", "application/json")
-				etcdErr.NewError(402, "", 0).Write(w)
-				return
-			}
-			uhttp.Redirect(s.peerServer.standbyClientURL, w, req)
-			return
-		}
-
 		// Execute handler function and return error if necessary.
 		if err := f(w, req); err != nil {
 			if etcdErr, ok := err.(*etcdErr.Error); ok {
@@ -231,9 +220,6 @@ func (s *Server) Dispatch(c raft.Command, w http.ResponseWriter, req *http.Reque
 			return etcdErr.NewError(300, "Empty result from raft", s.Store().Index())
 		}
 
-		w.Header().Set("X-Leader-Client-URL", s.url)
-		w.Header().Set("X-Leader-Peer-URL", ps.Config.URL)
-
 		// response for raft related commands[join/remove]
 		if b, ok := result.([]byte); ok {
 			w.WriteHeader(http.StatusOK)
@@ -276,8 +262,7 @@ func (s *Server) Dispatch(c raft.Command, w http.ResponseWriter, req *http.Reque
 
 	var url string
 	switch c.(type) {
-	case *JoinCommandV1, *RemoveCommandV1,
-		*JoinCommandV2, *RemoveCommandV2,
+	case *JoinCommand, *RemoveCommand,
 		*SetClusterConfigCommand:
 		url, _ = ps.registry.PeerURL(leader)
 	default:

server/v2/get_handler.go

@@ -132,11 +132,5 @@ func writeHeaders(w http.ResponseWriter, s Server) {
 	w.Header().Add("X-Etcd-Index", fmt.Sprint(s.Store().Index()))
 	w.Header().Add("X-Raft-Index", fmt.Sprint(s.CommitIndex()))
 	w.Header().Add("X-Raft-Term", fmt.Sprint(s.Term()))
-	if url, ok := s.ClientURL(s.Leader()); ok {
-		w.Header().Set("X-Leader-Client-URL", url)
-	}
-	if url, ok := s.PeerURL(s.Leader()); ok {
-		w.Header().Set("X-Leader-Peer-URL", url)
-	}
 	w.WriteHeader(http.StatusOK)
 }

tests/functional/remove_node_test.go

@@ -25,7 +25,7 @@ func TestRemoveNode(t *testing.T) {
 
 	c.SyncCluster()
 
-	rmReq, _ := http.NewRequest("DELETE", "http://127.0.0.1:7001/v2/admin/machines/node3", nil)
+	rmReq, _ := http.NewRequest("DELETE", "http://127.0.0.1:7001/remove/node3", nil)
 
 	client := &http.Client{}
 	for i := 0; i < 2; i++ {

tests/functional/proxy_test.go → tests/functional/standby_test.go

@@ -15,6 +15,8 @@ import (
 
 // Create a full cluster and then add extra an extra standby node.
 func TestStandby(t *testing.T) {
+	t.Skip("functionality unimplemented")
+
 	clusterSize := 10 // DefaultActiveSize + 1
 	_, etcds, err := CreateCluster(clusterSize, &os.ProcAttr{Files: []*os.File{nil, os.Stdout, os.Stderr}}, false)
 	assert.NoError(t, err)
@@ -85,6 +87,8 @@ func TestStandby(t *testing.T) {
 
 // Create a full cluster, disconnect a peer, wait for autodemotion, wait for autopromotion.
 func TestStandbyAutoPromote(t *testing.T) {
+	t.Skip("functionality unimplemented")
+
 	clusterSize := 10 // DefaultActiveSize + 1
 	_, etcds, err := CreateCluster(clusterSize, &os.ProcAttr{Files: []*os.File{nil, os.Stdout, os.Stderr}}, false)
 	if err != nil {