Promote WatchList feature to Beta (#128053)

* e2e/apimachinery/watchlist: always run WatchList e2e tests

* kube-controller-manager: enable WatchListClient

* kube-apiserver: promote WatchList feature to beta

cmd/kube-controller-manager/app/options/options.go

@@ -27,6 +27,7 @@ import (
 	apiserveroptions "k8s.io/apiserver/pkg/server/options"
 	utilfeature "k8s.io/apiserver/pkg/util/feature"
 	utilversion "k8s.io/apiserver/pkg/util/version"
+	clientgofeaturegate "k8s.io/client-go/features"
 	clientset "k8s.io/client-go/kubernetes"
 	clientgokubescheme "k8s.io/client-go/kubernetes/scheme"
 	restclient "k8s.io/client-go/rest"
@@ -35,10 +36,12 @@ import (
 	cpnames "k8s.io/cloud-provider/names"
 	cpoptions "k8s.io/cloud-provider/options"
 	cliflag "k8s.io/component-base/cli/flag"
+	"k8s.io/component-base/featuregate"
 	"k8s.io/component-base/logs"
 	logsapi "k8s.io/component-base/logs/api/v1"
 	"k8s.io/component-base/metrics"
 	cmoptions "k8s.io/controller-manager/options"
+	"k8s.io/klog/v2"
 	kubectrlmgrconfigv1alpha1 "k8s.io/kube-controller-manager/config/v1alpha1"
 	kubecontrollerconfig "k8s.io/kubernetes/cmd/kube-controller-manager/app/config"
 	"k8s.io/kubernetes/cmd/kube-controller-manager/names"
@@ -285,6 +288,16 @@ func (s *KubeControllerManagerOptions) Flags(allControllers []string, disabledBy
 	fs := fss.FlagSet("misc")
 	fs.StringVar(&s.Master, "master", s.Master, "The address of the Kubernetes API server (overrides any value in kubeconfig).")
 	fs.StringVar(&s.Generic.ClientConnection.Kubeconfig, "kubeconfig", s.Generic.ClientConnection.Kubeconfig, "Path to kubeconfig file with authorization and master location information (the master location can be overridden by the master flag).")
+
+	if !utilfeature.DefaultFeatureGate.Enabled(featuregate.Feature(clientgofeaturegate.WatchListClient)) {
+		if err := utilfeature.DefaultMutableFeatureGate.OverrideDefault(featuregate.Feature(clientgofeaturegate.WatchListClient), true); err != nil {
+			// it turns out that there are some integration tests that start multiple control plane components which
+			// share global DefaultFeatureGate/DefaultMutableFeatureGate variables.
+			// in those cases, the above call will fail (FG already registered and cannot be overridden), and the error will be logged.
+			klog.Errorf("unable to set %s feature gate, err: %v", clientgofeaturegate.WatchListClient, err)
+		}
+	}
+
 	s.ComponentGlobalsRegistry.AddFlags(fss.FlagSet("generic"))
 
 	return fss

cmd/kube-controller-manager/app/options/options_test.go

@@ -1455,8 +1455,8 @@ func TestWatchListClientFlagChange(t *testing.T) {
 
 func assertWatchListClientFeatureDefaultValue(t *testing.T) {
 	watchListClientDefaultValue := clientgofeaturegate.FeatureGates().Enabled(clientgofeaturegate.WatchListClient)
-	if watchListClientDefaultValue {
-		t.Fatalf("expected %q feature gate to be disabled for KCM", clientgofeaturegate.WatchListClient)
+	if !watchListClientDefaultValue {
+		t.Fatalf("expected %q feature gate to be enabled for KCM", clientgofeaturegate.WatchListClient)
 	}
 }
 
@@ -1467,7 +1467,7 @@ func assertWatchListCommandLineDefaultValue(t *testing.T, fs *pflag.FlagSet) {
 		t.Fatalf("didn't find %q flag", fgFlagName)
 	}
 
-	expectedWatchListClientString := "WatchListClient=true|false (BETA - default=false)"
+	expectedWatchListClientString := "WatchListClient=true|false (BETA - default=true)"
 	if !strings.Contains(fg.Usage, expectedWatchListClientString) {
 		t.Fatalf("%q flag doesn't contain the expected usage for %v feature gate.\nExpected = %v\nUsage = %v", fgFlagName, clientgofeaturegate.WatchListClient, expectedWatchListClientString, fg.Usage)
 	}

pkg/features/versioned_kube_features.go

@@ -335,6 +335,7 @@ var defaultVersionedKubernetesFeatureGates = map[featuregate.Feature]featuregate
 
 	genericfeatures.WatchList: {
 		{Version: version.MustParse("1.27"), Default: false, PreRelease: featuregate.Alpha},
+		{Version: version.MustParse("1.32"), Default: true, PreRelease: featuregate.Beta},
 	},
 
 	genericfeatures.ZeroLimitedNominalConcurrencyShares: {

staging/src/k8s.io/apiserver/pkg/features/kube_features.go

@@ -396,6 +396,7 @@ var defaultVersionedKubernetesFeatureGates = map[featuregate.Feature]featuregate
 
 	WatchList: {
 		{Version: version.MustParse("1.27"), Default: false, PreRelease: featuregate.Alpha},
+		{Version: version.MustParse("1.32"), Default: true, PreRelease: featuregate.Beta},
 	},
 
 	ZeroLimitedNominalConcurrencyShares: {

test/e2e/apimachinery/watchlist.go

@@ -44,11 +44,10 @@ import (
 	"k8s.io/client-go/util/consistencydetector"
 	"k8s.io/component-base/featuregate"
 	featuregatetesting "k8s.io/component-base/featuregate/testing"
-	"k8s.io/kubernetes/test/e2e/feature"
 	"k8s.io/kubernetes/test/e2e/framework"
 )
 
-var _ = SIGDescribe("API Streaming (aka. WatchList)", framework.WithSerial(), feature.WatchList, func() {
+var _ = SIGDescribe("API Streaming (aka. WatchList)", framework.WithSerial(), func() {
 	f := framework.NewDefaultFramework("watchlist")
 	ginkgo.It("should be requested by informers when WatchListClient is enabled", func(ctx context.Context) {
 		featuregatetesting.SetFeatureGateDuringTest(ginkgo.GinkgoTB(), utilfeature.DefaultFeatureGate, featuregate.Feature(clientfeatures.WatchListClient), true)

test/featuregates_linter/test_data/versioned_feature_list.yaml

@@ -1320,6 +1320,10 @@
     lockToDefault: false
     preRelease: Alpha
     version: "1.27"
+  - default: true
+    lockToDefault: false
+    preRelease: Beta
+    version: "1.32"
 - name: WindowsHostNetwork
   versionedSpecs:
   - default: true