Make sure there are no duplicates in etcd member list (#4025)

pkg/cli/server/server.go

@@ -223,6 +223,7 @@ func run(app *cli.Context, cfg *cmds.Server, leaderControllers server.CustomCont
 	if err != nil {
 		return err
 	}
+	serverConfig.ControlConfig.ServerNodeName = nodeName
 	serverConfig.ControlConfig.SANs = append(serverConfig.ControlConfig.SANs, "127.0.0.1", "localhost", nodeName)
 	for _, ip := range nodeIPs {
 		serverConfig.ControlConfig.SANs = append(serverConfig.ControlConfig.SANs, ip.String())

pkg/daemons/config/types.go

@@ -168,6 +168,7 @@ type Control struct {
 	EtcdS3Region             string
 	EtcdS3Folder             string
 	EtcdS3Insecure           bool
+	ServerNodeName           string
 
 	BindAddress string
 	SANs        []string

pkg/etcd/etcd.go

@@ -329,6 +329,16 @@ func (e *ETCD) join(ctx context.Context, clientAccessInfo *clientaccess.Info) er
 	}
 
 	for _, member := range members.Members {
+		lastHyphen := strings.LastIndex(member.Name, "-")
+		memberNodeName := member.Name[:lastHyphen]
+		if memberNodeName == e.config.ServerNodeName {
+			// make sure to remove the name file if a duplicate node name is used
+			nameFile := nameFile(e.config)
+			if err := os.Remove(nameFile); err != nil {
+				return err
+			}
+			return errors.New("Failed to join etcd cluster due to duplicate node names, please use unique node name for the server")
+		}
 		for _, peer := range member.PeerURLs {
 			u, err := url.Parse(peer)
 			if err != nil {
@@ -414,11 +424,7 @@ func (e *ETCD) setName(force bool) error {
 	fileName := nameFile(e.config)
 	data, err := ioutil.ReadFile(fileName)
 	if os.IsNotExist(err) || force {
-		h, err := os.Hostname()
-		if err != nil {
-			return err
-		}
-		e.name = strings.SplitN(h, ".", 2)[0] + "-" + uuid.New().String()[:8]
+		e.name = e.config.ServerNodeName + "-" + uuid.New().String()[:8]
 		if err := os.MkdirAll(filepath.Dir(fileName), 0700); err != nil {
 			return err
 		}