Merge pull request #2761 from yichengq/344

etcdmain: advertise-client-urls must be set if listen-client-urls is set

etcdmain/config.go

@@ -61,6 +61,7 @@ var (
 
 	ErrConflictBootstrapFlags = fmt.Errorf("multiple discovery or bootstrap flags are set" +
 		"Choose one of \"initial-cluster\", \"discovery\" or \"discovery-srv\"")
+	errUnsetAdvertiseClientURLsFlag = fmt.Errorf("-advertise-client-urls is required when -listen-client-urls is set explicitly")
 )
 
 type config struct {
@@ -264,6 +265,9 @@ func (cfg *config) Parse(arguments []string) error {
 	if err != nil {
 		return err
 	}
+	if flags.IsSet(cfg.FlagSet, "listen-client-urls") && !flags.IsSet(cfg.FlagSet, "advertise-client-urls") {
+		return errUnsetAdvertiseClientURLsFlag
+	}
 
 	if 5*cfg.TickMs > cfg.ElectionMs {
 		return fmt.Errorf("-election-timeout[%vms] should be at least as 5 times as -heartbeat-interval[%vms]", cfg.ElectionMs, cfg.TickMs)

etcdmain/config_test.go

@@ -29,6 +29,8 @@ func TestConfigParsingMemberFlags(t *testing.T) {
 		"-snapshot-count=10",
 		"-listen-peer-urls=http://localhost:8000,https://localhost:8001",
 		"-listen-client-urls=http://localhost:7000,https://localhost:7001",
+		// it should be set if -listen-client-urls is set
+		"-advertise-client-urls=http://localhost:7000,https://localhost:7001",
 	}
 	wcfg := &config{
 		dir:          "testdir",

etcdmain/etcd.go

@@ -60,7 +60,12 @@ func Main() {
 	cfg := NewConfig()
 	err := cfg.Parse(os.Args[1:])
 	if err != nil {
-		log.Fatalf("error verifying flags, %v. See 'etcd -help'.", err)
+		log.Printf("error verifying flags, %v. See 'etcd -help'.", err)
+		switch err {
+		case errUnsetAdvertiseClientURLsFlag:
+			log.Printf("When listening on specific address(es), this etcd process must advertise accessible url(s) to each connected client.")
+		}
+		os.Exit(1)
 	}
 	setupLogging(cfg)
 

etcdmain/help.go

@@ -56,7 +56,8 @@ clustering flags:
 	--initial-cluster-token 'etcd-cluster'
 		initial cluster token for the etcd cluster during bootstrap.
 	--advertise-client-urls 'http://localhost:2379,http://localhost:4001'
-		list of this member's client URLs to advertise to the rest of the cluster.
+		list of this member's client URLs to advertise to the public.
+		The client URLs advertised should be accessible to machines that talk to etcd cluster. etcd client libraries parse these URLs to connect to the cluster.
 	--discovery ''
 		discovery URL used to bootstrap the cluster.
 	--discovery-fallback 'proxy'