Migrate --experimental-set-member-localaddr to using feature flag

Signed-off-by: Chun-Hung Tseng <henrytseng@google.com>
Co-authored-by: Benjamin Wang <benjamin.wang@broadcom.com>

CHANGELOG/CHANGELOG-3.6.md

@@ -78,7 +78,7 @@ See [code changes](https://github.com/etcd-io/etcd/compare/v3.5.0...v3.6.0).
 - Decreased [`--snapshot-count` default value from 100,000 to 10,000](https://github.com/etcd-io/etcd/pull/15408)
 - Add [`etcd --tls-min-version --tls-max-version`](https://github.com/etcd-io/etcd/pull/15156) to enable support for TLS 1.3.
 - Add [quota to endpoint status response](https://github.com/etcd-io/etcd/pull/17877)
-- Add ['etcd --experimental-set-member-localaddr'](https://github.com/etcd-io/etcd/pull/17661) to enable using the first specified and non-loopback local address from initial-advertise-peer-urls as the local address when communicating with a peer.
+- Add [feature gate `SetMemberLocalAddr`](https://github.com/etcd-io/etcd/pull/19413) to [enable using the first specified and non-loopback local address from initial-advertise-peer-urls as the local address when communicating with a peer]((https://github.com/etcd-io/etcd/pull/17661))
 - Add [Support multiple values for allowed client and peer TLS identities](https://github.com/etcd-io/etcd/pull/18015)
 - Add [`embed.Config.GRPCAdditionalServerOptions`](https://github.com/etcd-io/etcd/pull/14066) to support updating the default internal gRPC configuration for embedded use cases.
 

server/embed/config.go

@@ -285,11 +285,6 @@ type Config struct {
 	PeerTLSInfo   transport.TLSInfo
 	PeerAutoTLS   bool
 
-	// ExperimentalSetMemberLocalAddr enables using the first specified and
-	// non-loopback local address from initial-advertise-peer-urls as the local
-	// address when communicating with a peer.
-	ExperimentalSetMemberLocalAddr bool `json:"experimental-set-member-localaddr"`
-
 	// SelfSignedCertValidity specifies the validity period of the client and peer certificates
 	// that are automatically generated by etcd when you specify ClientAutoTLS and PeerAutoTLS,
 	// the unit is year, and the default is 1
@@ -814,7 +809,6 @@ func (cfg *Config) AddFlags(fs *flag.FlagSet) {
 		"initial-advertise-peer-urls",
 		"List of this member's peer URLs to advertise to the rest of the cluster.",
 	)
-	fs.BoolVar(&cfg.ExperimentalSetMemberLocalAddr, "experimental-set-member-localaddr", false, "Enable to have etcd use the first specified and non-loopback host from initial-advertise-peer-urls as the local address when communicating with a peer.")
 
 	fs.Var(
 		flags.NewUniqueURLsWithExceptions(DefaultAdvertiseClientURLs, ""),
@@ -1475,7 +1469,7 @@ func (cfg *Config) InitialClusterFromName(name string) (ret string) {
 // non-loopback address. Otherwise, it defaults to empty string and the
 // LocalAddr used will be the default for the Golang HTTP client.
 func (cfg *Config) InferLocalAddr() string {
-	if !cfg.ExperimentalSetMemberLocalAddr {
+	if !cfg.ServerFeatureGate.Enabled(features.SetMemberLocalAddr) {
 		return ""
 	}
 

server/embed/config_test.go

@@ -149,7 +149,7 @@ func TestConfigFileFeatureGates(t *testing.T) {
 		},
 		{
 			name:                                "ok to set different multiple experimental flags and feature gate flags",
-			serverFeatureGatesJSON:              "StopGRPCServiceOnDefrag=true,TxnModeWriteWithSharedBuffer=true,LeaseCheckpoint=true",
+			serverFeatureGatesJSON:              "StopGRPCServiceOnDefrag=true,TxnModeWriteWithSharedBuffer=true,LeaseCheckpoint=true,SetMemberLocalAddr=true",
 			experimentalCompactHashCheckEnabled: "true",
 			experimentalInitialCorruptCheck:     "true",
 			expectedFeatures: map[featuregate.Feature]bool{
@@ -158,6 +158,7 @@ func TestConfigFileFeatureGates(t *testing.T) {
 				features.InitialCorruptCheck:          true,
 				features.TxnModeWriteWithSharedBuffer: true,
 				features.LeaseCheckpoint:              true,
+				features.SetMemberLocalAddr:           true,
 			},
 		},
 		{
@@ -440,117 +441,117 @@ func TestInferLocalAddr(t *testing.T) {
 	tests := []struct {
 		name               string
 		advertisePeerURLs  []string
-		setMemberLocalAddr bool
+		serverFeatureGates string
 		expectedLocalAddr  string
 	}{
 		{
 			"defaults, ExperimentalSetMemberLocalAddr=false ",
 			[]string{DefaultInitialAdvertisePeerURLs},
-			false,
+			"SetMemberLocalAddr=false",
 			"",
 		},
 		{
 			"IPv4 address, ExperimentalSetMemberLocalAddr=false ",
 			[]string{"https://192.168.100.110:2380"},
-			false,
+			"SetMemberLocalAddr=false",
 			"",
 		},
 		{
 			"defaults, ExperimentalSetMemberLocalAddr=true",
 			[]string{DefaultInitialAdvertisePeerURLs},
-			true,
+			"SetMemberLocalAddr=true",
 			"",
 		},
 		{
 			"IPv4 unspecified address, ExperimentalSetMemberLocalAddr=true",
 			[]string{"https://0.0.0.0:2380"},
-			true,
+			"SetMemberLocalAddr=true",
 			"",
 		},
 		{
 			"IPv6 unspecified address, ExperimentalSetMemberLocalAddr=true",
 			[]string{"https://[::]:2380"},
-			true,
+			"SetMemberLocalAddr=true",
 			"",
 		},
 		{
 			"IPv4 loopback address, ExperimentalSetMemberLocalAddr=true",
 			[]string{"https://127.0.0.1:2380"},
-			true,
+			"SetMemberLocalAddr=true",
 			"",
 		},
 		{
 			"IPv6 loopback address, ExperimentalSetMemberLocalAddr=true",
 			[]string{"https://[::1]:2380"},
-			true,
+			"SetMemberLocalAddr=true",
 			"",
 		},
 		{
 			"IPv4 address, ExperimentalSetMemberLocalAddr=true",
 			[]string{"https://192.168.100.110:2380"},
-			true,
+			"SetMemberLocalAddr=true",
 			"192.168.100.110",
 		},
 		{
 			"Hostname only, ExperimentalSetMemberLocalAddr=true",
 			[]string{"https://123-host-3.corp.internal:2380"},
-			true,
+			"SetMemberLocalAddr=true",
 			"",
 		},
 		{
 			"Hostname and IPv4 address, ExperimentalSetMemberLocalAddr=true",
 			[]string{"https://123-host-3.corp.internal:2380", "https://192.168.100.110:2380"},
-			true,
+			"SetMemberLocalAddr=true",
 			"192.168.100.110",
 		},
 		{
 			"IPv4 address and Hostname, ExperimentalSetMemberLocalAddr=true",
 			[]string{"https://192.168.100.110:2380", "https://123-host-3.corp.internal:2380"},
-			true,
+			"SetMemberLocalAddr=true",
 			"192.168.100.110",
 		},
 		{
 			"IPv4 and IPv6 addresses, ExperimentalSetMemberLocalAddr=true",
 			[]string{"https://192.168.100.110:2380", "https://[2001:db8:85a3::8a2e:370:7334]:2380"},
-			true,
+			"SetMemberLocalAddr=true",
 			"192.168.100.110",
 		},
 		{
 			"IPv6 and IPv4 addresses, ExperimentalSetMemberLocalAddr=true",
 			// IPv4 addresses will always sort before IPv6 ones anyway
 			[]string{"https://[2001:db8:85a3::8a2e:370:7334]:2380", "https://192.168.100.110:2380"},
-			true,
+			"SetMemberLocalAddr=true",
 			"192.168.100.110",
 		},
 		{
 			"Hostname, IPv4 and IPv6 addresses, ExperimentalSetMemberLocalAddr=true",
 			[]string{"https://123-host-3.corp.internal:2380", "https://192.168.100.110:2380", "https://[2001:db8:85a3::8a2e:370:7334]:2380"},
-			true,
+			"SetMemberLocalAddr=true",
 			"192.168.100.110",
 		},
 		{
 			"Hostname, IPv6 and IPv4 addresses, ExperimentalSetMemberLocalAddr=true",
 			// IPv4 addresses will always sort before IPv6 ones anyway
 			[]string{"https://123-host-3.corp.internal:2380", "https://[2001:db8:85a3::8a2e:370:7334]:2380", "https://192.168.100.110:2380"},
-			true,
+			"SetMemberLocalAddr=true",
 			"192.168.100.110",
 		},
 		{
 			"IPv6 address, ExperimentalSetMemberLocalAddr=true",
 			[]string{"https://[2001:db8:85a3::8a2e:370:7334]:2380"},
-			true,
+			"SetMemberLocalAddr=true",
 			"2001:db8:85a3::8a2e:370:7334",
 		},
 		{
 			"Hostname and IPv6 address, ExperimentalSetMemberLocalAddr=true",
 			[]string{"https://123-host-3.corp.internal:2380", "https://[2001:db8:85a3::8a2e:370:7334]:2380"},
-			true,
+			"SetMemberLocalAddr=true",
 			"2001:db8:85a3::8a2e:370:7334",
 		},
 		{
 			"IPv6 address and Hostname, ExperimentalSetMemberLocalAddr=true",
 			[]string{"https://[2001:db8:85a3::8a2e:370:7334]:2380", "https://123-host-3.corp.internal:2380"},
-			true,
+			"SetMemberLocalAddr=true",
 			"2001:db8:85a3::8a2e:370:7334",
 		},
 	}
@@ -559,7 +560,7 @@ func TestInferLocalAddr(t *testing.T) {
 		t.Run(tt.name, func(t *testing.T) {
 			cfg := NewConfig()
 			cfg.AdvertisePeerUrls = types.MustNewURLs(tt.advertisePeerURLs)
-			cfg.ExperimentalSetMemberLocalAddr = tt.setMemberLocalAddr
+			cfg.ServerFeatureGate.(featuregate.MutableFeatureGate).Set(tt.serverFeatureGates)
 
 			require.NoError(t, cfg.Validate())
 			require.Equal(t, tt.expectedLocalAddr, cfg.InferLocalAddr())
@@ -567,6 +568,29 @@ func TestInferLocalAddr(t *testing.T) {
 	}
 }
 
+func TestSetMemberLocalAddrValidate(t *testing.T) {
+	tcs := []struct {
+		name               string
+		serverFeatureGates string
+	}{
+		{
+			name: "Default config should pass",
+		},
+		{
+			name:               "Enabling SetMemberLocalAddr should pass",
+			serverFeatureGates: "SetMemberLocalAddr=true",
+		},
+	}
+	for _, tc := range tcs {
+		t.Run(tc.name, func(t *testing.T) {
+			cfg := *NewConfig()
+			cfg.ServerFeatureGate.(featuregate.MutableFeatureGate).Set(tc.serverFeatureGates)
+			err := cfg.Validate()
+			require.NoError(t, err)
+		})
+	}
+}
+
 func (s *securityConfig) equals(t *transport.TLSInfo) bool {
 	return s.CertFile == t.CertFile &&
 		s.CertAuth == t.ClientCertAuth &&

server/embed/etcd.go

@@ -348,7 +348,6 @@ func print(lg *zap.Logger, ec Config, sc config.ServerConfig, memberInitialized
 		zap.Strings("advertise-client-urls", ec.getAdvertiseClientURLs()),
 		zap.Strings("listen-client-urls", ec.getListenClientURLs()),
 		zap.Strings("listen-metrics-urls", ec.getMetricsURLs()),
-		zap.Bool("experimental-set-member-localaddr", ec.ExperimentalSetMemberLocalAddr),
 		zap.String("experimental-local-address", sc.ExperimentalLocalAddress),
 		zap.Strings("cors", cors),
 		zap.Strings("host-whitelist", hss),

server/etcdmain/help.go

@@ -113,8 +113,6 @@ Member:
 Clustering:
   --initial-advertise-peer-urls 'http://localhost:2380'
     List of this member's peer URLs to advertise to the rest of the cluster.
-  --experimental-set-member-localaddr 'false'
-    Enable using the first specified and non-loopback local address from initial-advertise-peer-urls as the local address when communicating with a peer.
   --initial-cluster 'default=http://localhost:2380'
     Initial cluster configuration for bootstrapping.
   --initial-cluster-state 'new'

server/features/etcd_features.go

@@ -73,6 +73,12 @@ const (
 	// main PR: https://github.com/etcd-io/etcd/pull/13508
 	// Deprecated: Enabled by default in v3.6, to be removed in v3.7.
 	LeaseCheckpointPersist featuregate.Feature = "LeaseCheckpointPersist"
+	// SetMemberLocalAddr enables using the first specified and non-loopback local address from initial-advertise-peer-urls as the local address when communicating with a peer.
+	// Requires SetMemberLocalAddr featuragate to be enabled.
+	// owner: @flawedmatrix
+	// alpha: v3.6
+	// main PR: https://github.com/etcd-io/etcd/pull/17661
+	SetMemberLocalAddr featuregate.Feature = "SetMemberLocalAddr"
 )
 
 var (
@@ -84,6 +90,7 @@ var (
 		TxnModeWriteWithSharedBuffer: {Default: true, PreRelease: featuregate.Beta},
 		LeaseCheckpoint:              {Default: false, PreRelease: featuregate.Alpha},
 		LeaseCheckpointPersist:       {Default: false, PreRelease: featuregate.Alpha},
+		SetMemberLocalAddr:           {Default: false, PreRelease: featuregate.Alpha},
 	}
 	// ExperimentalFlagToFeatureMap is the map from the cmd line flags of experimental features
 	// to their corresponding feature gates.

tests/e2e/etcd_config_test.go

@@ -427,7 +427,7 @@ func TestEtcdPeerLocalAddr(t *testing.T) {
 		os.RemoveAll(tempDir)
 	}()
 
-	// node 0 (127.0.0.1) does not set `--experimental-set-member-localaddr`,
+	// node 0 (127.0.0.1) does not set `--feature-gates=SetMemberLocalAddr=true`,
 	// while nodes 1 and nodes 2 do.
 	//
 	// node 0's peer certificate is signed for 127.0.0.1, but it uses the host
@@ -437,7 +437,7 @@ func TestEtcdPeerLocalAddr(t *testing.T) {
 	// Both node 1 and node 2's peer certificates are signed for the host IP,
 	// and they also communicate with peers using the host IP (explicitly set
 	// with --initial-advertise-peer-urls and
-	// --experimental-set-member-localaddr), so node 0 has no issue connecting
+	// --feature-gates=SetMemberLocalAddr=true), so node 0 has no issue connecting
 	// to them.
 	//
 	// Refer to https://github.com/etcd-io/etcd/issues/17068.
@@ -472,7 +472,7 @@ func TestEtcdPeerLocalAddr(t *testing.T) {
 				"--peer-key-file", keyFiles[1],
 				"--peer-trusted-ca-file", caFile,
 				"--peer-client-cert-auth",
-				"--experimental-set-member-localaddr",
+				"--feature-gates=SetMemberLocalAddr=true",
 			}
 		}