KEP-4578: migrate experimental-enable-lease-checkpoint and experimental-enable-lease-checkpoint-persist flag to feature gate.

server/embed/config.go

@@ -1070,11 +1070,11 @@ func (cfg *Config) Validate() error {
 		}
 	}
 
-	if !cfg.ExperimentalEnableLeaseCheckpointPersist && cfg.ExperimentalEnableLeaseCheckpoint {
+	if !cfg.ServerFeatureGate.Enabled(features.EnableLeaseCheckpointPersist) && cfg.ServerFeatureGate.Enabled(features.EnableLeaseCheckpoint) {
 		cfg.logger.Warn("Detected that checkpointing is enabled without persistence. Consider enabling experimental-enable-lease-checkpoint-persist")
 	}
 
-	if cfg.ExperimentalEnableLeaseCheckpointPersist && !cfg.ExperimentalEnableLeaseCheckpoint {
+	if cfg.ServerFeatureGate.Enabled(features.EnableLeaseCheckpointPersist) && !cfg.ServerFeatureGate.Enabled(features.EnableLeaseCheckpoint) {
 		return fmt.Errorf("setting experimental-enable-lease-checkpoint-persist requires experimental-enable-lease-checkpoint")
 	}
 

server/embed/config_test.go

@@ -103,8 +103,10 @@ func TestConfigFileFeatureGates(t *testing.T) {
 		{
 			name: "default",
 			expectedFeatures: map[featuregate.Feature]bool{
-				features.DistributedTracing:      false,
-				features.StopGRPCServiceOnDefrag: false,
+				features.DistributedTracing:           false,
+				features.StopGRPCServiceOnDefrag:      false,
+				features.EnableLeaseCheckpoint:        false,
+				features.EnableLeaseCheckpointPersist: false,
 			},
 		},
 		{
@@ -126,32 +128,40 @@ func TestConfigFileFeatureGates(t *testing.T) {
 			name:                                "can set feature gate to true from experimental flag",
 			experimentalStopGRPCServiceOnDefrag: "true",
 			expectedFeatures: map[featuregate.Feature]bool{
-				features.StopGRPCServiceOnDefrag: true,
-				features.DistributedTracing:      false,
+				features.StopGRPCServiceOnDefrag:      true,
+				features.DistributedTracing:           false,
+				features.EnableLeaseCheckpoint:        false,
+				features.EnableLeaseCheckpointPersist: false,
 			},
 		},
 		{
 			name:                                "can set feature gate to false from experimental flag",
 			experimentalStopGRPCServiceOnDefrag: "false",
 			expectedFeatures: map[featuregate.Feature]bool{
-				features.StopGRPCServiceOnDefrag: false,
-				features.DistributedTracing:      false,
+				features.StopGRPCServiceOnDefrag:      false,
+				features.DistributedTracing:           false,
+				features.EnableLeaseCheckpoint:        false,
+				features.EnableLeaseCheckpointPersist: false,
 			},
 		},
 		{
 			name:                   "can set feature gate to true from feature gate flag",
 			serverFeatureGatesJSON: "StopGRPCServiceOnDefrag=true",
 			expectedFeatures: map[featuregate.Feature]bool{
-				features.StopGRPCServiceOnDefrag: true,
-				features.DistributedTracing:      false,
+				features.StopGRPCServiceOnDefrag:      true,
+				features.DistributedTracing:           false,
+				features.EnableLeaseCheckpoint:        false,
+				features.EnableLeaseCheckpointPersist: false,
 			},
 		},
 		{
 			name:                   "can set feature gate to false from feature gate flag",
 			serverFeatureGatesJSON: "StopGRPCServiceOnDefrag=false",
 			expectedFeatures: map[featuregate.Feature]bool{
-				features.StopGRPCServiceOnDefrag: false,
-				features.DistributedTracing:      false,
+				features.StopGRPCServiceOnDefrag:      false,
+				features.DistributedTracing:           false,
+				features.EnableLeaseCheckpoint:        false,
+				features.EnableLeaseCheckpointPersist: false,
 			},
 		},
 	}
@@ -563,6 +573,12 @@ func TestPeerURLsMapAndTokenFromSRV(t *testing.T) {
 	}
 }
 
+func SetFeatureGateDuringTest(cfg Config, fgname string, value bool) {
+	if err := cfg.ServerFeatureGate.(featuregate.MutableFeatureGate).Set(fmt.Sprintf("%s=%v", fgname, true)); err != nil {
+		panic(err)
+	}
+}
+
 func TestLeaseCheckpointValidate(t *testing.T) {
 	tcs := []struct {
 		name        string
@@ -575,6 +591,14 @@ func TestLeaseCheckpointValidate(t *testing.T) {
 				return *NewConfig()
 			},
 		},
+		{
+			name: "Enabling checkpoint leases with feature gate should pass",
+			configFunc: func() Config {
+				cfg := *NewConfig()
+				SetFeatureGateDuringTest(cfg, "EnableLeaseCheckpoint", true)
+				return cfg
+			},
+		},
 		{
 			name: "Enabling checkpoint leases should pass",
 			configFunc: func() Config {
@@ -592,6 +616,15 @@ func TestLeaseCheckpointValidate(t *testing.T) {
 				return cfg
 			},
 		},
+		{
+			name: "Enabling checkpoint leases and persist with feature gate should pass",
+			configFunc: func() Config {
+				cfg := *NewConfig()
+				SetFeatureGateDuringTest(cfg, "EnableLeaseCheckpoint", true)
+				SetFeatureGateDuringTest(cfg, "EnableLeaseCheckpointPersist", true)
+				return cfg
+			},
+		},
 		{
 			name: "Enabling checkpoint leases persist without checkpointing itself should fail",
 			configFunc: func() Config {

server/embed/etcd.go

@@ -213,7 +213,6 @@ func StartEtcd(inCfg *Config) (e *Etcd, err error) {
 		EnableGRPCGateway:                        cfg.EnableGRPCGateway,
 		ExperimentalEnableDistributedTracing:     cfg.ExperimentalEnableDistributedTracing,
 		UnsafeNoFsync:                            cfg.UnsafeNoFsync,
-		EnableLeaseCheckpoint:                    cfg.ExperimentalEnableLeaseCheckpoint,
 		LeaseCheckpointPersist:                   cfg.ExperimentalEnableLeaseCheckpointPersist,
 		CompactionBatchLimit:                     cfg.ExperimentalCompactionBatchLimit,
 		CompactionSleepInterval:                  cfg.ExperimentalCompactionSleepInterval,

server/etcdmain/help.go

@@ -281,7 +281,7 @@ Experimental feature:
     Enable leader to periodically check followers compaction hashes.
   --experimental-compact-hash-check-time '1m'
     Duration of time between leader checks followers compaction hashes.
-  --experimental-enable-lease-checkpoint 'false'
+  --experimental-enable-lease-checkpoint 'false'.It's deprecated, and will be decommissioned in v3.7. Use '--feature-gates=EnableLeaseCheckpoint=true' instead.
     ExperimentalEnableLeaseCheckpoint enables primary lessor to persist lease remainingTTL to prevent indefinite auto-renewal of long lived leases.
   --experimental-compaction-batch-limit 1000
     ExperimentalCompactionBatchLimit sets the maximum revisions deleted in each compaction batch.
@@ -305,7 +305,7 @@ Experimental feature:
     Sets the sleep interval between each compaction batch.
   --experimental-downgrade-check-time
     Duration of time between two downgrade status checks.
-  --experimental-enable-lease-checkpoint-persist 'false'
+  --experimental-enable-lease-checkpoint-persist 'false'.It's deprecated, and will be decommissioned in v3.7. Use '--feature-gates=EnableLeaseCheckpointPersist=true' instead.
     Enable persisting remainingTTL to prevent indefinite auto-renewal of long lived leases. Always enabled in v3.6. Should be used to ensure smooth upgrade from v3.5 clusters with this feature enabled. Requires experimental-enable-lease-checkpoint to be enabled.
   --experimental-memory-mlock
     Enable to enforce etcd pages (in particular bbolt) to stay in RAM.

server/etcdserver/server.go

@@ -63,6 +63,7 @@ import (
 	"go.etcd.io/etcd/server/v3/etcdserver/errors"
 	"go.etcd.io/etcd/server/v3/etcdserver/txn"
 	serverversion "go.etcd.io/etcd/server/v3/etcdserver/version"
+	"go.etcd.io/etcd/server/v3/features"
 	"go.etcd.io/etcd/server/v3/lease"
 	"go.etcd.io/etcd/server/v3/lease/leasehttp"
 	serverstorage "go.etcd.io/etcd/server/v3/storage"
@@ -350,7 +351,7 @@ func NewServer(cfg config.ServerConfig) (srv *EtcdServer, err error) {
 	srv.lessor = lease.NewLessor(srv.Logger(), srv.be, srv.cluster, lease.LessorConfig{
 		MinLeaseTTL:                int64(math.Ceil(minTTL.Seconds())),
 		CheckpointInterval:         cfg.LeaseCheckpointInterval,
-		CheckpointPersist:          cfg.LeaseCheckpointPersist,
+		CheckpointPersist:          cfg.ServerFeatureGate.Enabled(features.EnableLeaseCheckpointPersist),
 		ExpiredLeasesRetryInterval: srv.Cfg.ReqTimeout(),
 	})
 
@@ -395,7 +396,7 @@ func NewServer(cfg config.ServerConfig) (srv *EtcdServer, err error) {
 	}
 	srv.uberApply = srv.NewUberApplier()
 
-	if srv.Cfg.EnableLeaseCheckpoint {
+	if srv.FeatureEnabled(features.EnableLeaseCheckpoint) {
 		// setting checkpointer enables lease checkpoint feature.
 		srv.lessor.SetCheckpointer(func(ctx context.Context, cp *pb.LeaseCheckpointRequest) error {
 			if !srv.ensureLeadership() {

server/features/etcd_features.go

@@ -45,18 +45,35 @@ const (
 	// alpha: v3.6
 	// main PR: https://github.com/etcd-io/etcd/pull/18279
 	StopGRPCServiceOnDefrag featuregate.Feature = "StopGRPCServiceOnDefrag"
+
+	// EnableLeaseCheckpoint enables leader to send regular checkpoints to other members to prevent reset of remaining TTL on leader change.
+	// owner: @
+	// alpha: v3.6
+	EnableLeaseCheckpoint featuregate.Feature = "EnableLeaseCheckpoint"
+	// EnableLeaseCheckpointPersist enables persisting remainingTTL to prevent indefinite auto-renewal of long lived leases. Always enabled in v3.6. Should be used to ensure smooth upgrade from v3.5 clusters with this feature enabled.
+	// Requires EnableLeaseCheckpoint featuragate to be enabled.
+	// Deprecated in v3.6.
+	// TODO: Delete in v3.7
+	// owner: @serathius
+	// alpha: v3.6
+	// main PR: https://github.com/etcd-io/etcd/pull/13508
+	EnableLeaseCheckpointPersist featuregate.Feature = "EnableLeaseCheckpointPersist"
 )
 
 var (
 	DefaultEtcdServerFeatureGates = map[featuregate.Feature]featuregate.FeatureSpec{
-		DistributedTracing:      {Default: false, PreRelease: featuregate.Alpha},
-		StopGRPCServiceOnDefrag: {Default: false, PreRelease: featuregate.Alpha},
+		DistributedTracing:           {Default: false, PreRelease: featuregate.Alpha},
+		StopGRPCServiceOnDefrag:      {Default: false, PreRelease: featuregate.Alpha},
+		EnableLeaseCheckpoint:        {Default: false, PreRelease: featuregate.Alpha},
+		EnableLeaseCheckpointPersist: {Default: false, PreRelease: featuregate.Alpha},
 	}
 	// ExperimentalFlagToFeatureMap is the map from the cmd line flags of experimental features
 	// to their corresponding feature gates.
 	// Deprecated: only add existing experimental features here. DO NOT use for new features.
 	ExperimentalFlagToFeatureMap = map[string]featuregate.Feature{
-		"experimental-stop-grpc-service-on-defrag": StopGRPCServiceOnDefrag,
+		"experimental-stop-grpc-service-on-defrag":     StopGRPCServiceOnDefrag,
+		"experimental-enable-lease-checkpoint":         EnableLeaseCheckpoint,
+		"experimental-enable-lease-checkpoint-persist": EnableLeaseCheckpointPersist,
 	}
 )