Merge pull request #95885 from jiahuif/refactor/controller-manager

refactor: controller manager: InitFunc and base controller interface.

cmd/cloud-controller-manager/nodeipamcontroller.go

@@ -23,7 +23,6 @@ import (
 	"errors"
 	"fmt"
 	"net"
-	"net/http"
 	"strings"
 
 	utilfeature "k8s.io/apiserver/pkg/util/feature"
@@ -31,6 +30,7 @@ import (
 	"k8s.io/cloud-provider/app"
 	cloudcontrollerconfig "k8s.io/cloud-provider/app/config"
 	genericcontrollermanager "k8s.io/controller-manager/app"
+	"k8s.io/controller-manager/controller"
 	"k8s.io/controller-manager/pkg/features"
 	"k8s.io/klog/v2"
 	nodeipamcontrolleroptions "k8s.io/kubernetes/cmd/kube-controller-manager/app/options"
@@ -59,12 +59,12 @@ func (nodeIpamController *nodeIPAMController) StartNodeIpamControllerWrapper(ini
 	}
 	nodeIpamController.nodeIPAMControllerOptions.ApplyTo(&nodeIpamController.nodeIPAMControllerConfiguration)
 
-	return func(ctx genericcontrollermanager.ControllerContext) (http.Handler, bool, error) {
+	return func(ctx genericcontrollermanager.ControllerContext) (controller.Interface, bool, error) {
 		return startNodeIpamController(initContext, completedConfig, nodeIpamController.nodeIPAMControllerConfiguration, ctx, cloud)
 	}
 }
 
-func startNodeIpamController(initContext app.ControllerInitContext, ccmConfig *cloudcontrollerconfig.CompletedConfig, nodeIPAMConfig nodeipamconfig.NodeIPAMControllerConfiguration, ctx genericcontrollermanager.ControllerContext, cloud cloudprovider.Interface) (http.Handler, bool, error) {
+func startNodeIpamController(initContext app.ControllerInitContext, ccmConfig *cloudcontrollerconfig.CompletedConfig, nodeIPAMConfig nodeipamconfig.NodeIPAMControllerConfiguration, ctx genericcontrollermanager.ControllerContext, cloud cloudprovider.Interface) (controller.Interface, bool, error) {
 	var serviceCIDR *net.IPNet
 	var secondaryServiceCIDR *net.IPNet
 

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

@@ -22,17 +22,17 @@ package app
 
 import (
 	"fmt"
-	"net/http"
 	"time"
 
 	"k8s.io/client-go/util/flowcontrol"
+	"k8s.io/controller-manager/controller"
 	"k8s.io/kubernetes/pkg/controller/daemon"
 	"k8s.io/kubernetes/pkg/controller/deployment"
 	"k8s.io/kubernetes/pkg/controller/replicaset"
 	"k8s.io/kubernetes/pkg/controller/statefulset"
 )
 
-func startDaemonSetController(ctx ControllerContext) (http.Handler, bool, error) {
+func startDaemonSetController(ctx ControllerContext) (controller.Interface, bool, error) {
 	dsc, err := daemon.NewDaemonSetsController(
 		ctx.InformerFactory.Apps().V1().DaemonSets(),
 		ctx.InformerFactory.Apps().V1().ControllerRevisions(),
@@ -48,7 +48,7 @@ func startDaemonSetController(ctx ControllerContext) (http.Handler, bool, error)
 	return nil, true, nil
 }
 
-func startStatefulSetController(ctx ControllerContext) (http.Handler, bool, error) {
+func startStatefulSetController(ctx ControllerContext) (controller.Interface, bool, error) {
 	go statefulset.NewStatefulSetController(
 		ctx.InformerFactory.Core().V1().Pods(),
 		ctx.InformerFactory.Apps().V1().StatefulSets(),
@@ -59,7 +59,7 @@ func startStatefulSetController(ctx ControllerContext) (http.Handler, bool, erro
 	return nil, true, nil
 }
 
-func startReplicaSetController(ctx ControllerContext) (http.Handler, bool, error) {
+func startReplicaSetController(ctx ControllerContext) (controller.Interface, bool, error) {
 	go replicaset.NewReplicaSetController(
 		ctx.InformerFactory.Apps().V1().ReplicaSets(),
 		ctx.InformerFactory.Core().V1().Pods(),
@@ -69,7 +69,7 @@ func startReplicaSetController(ctx ControllerContext) (http.Handler, bool, error
 	return nil, true, nil
 }
 
-func startDeploymentController(ctx ControllerContext) (http.Handler, bool, error) {
+func startDeploymentController(ctx ControllerContext) (controller.Interface, bool, error) {
 	dc, err := deployment.NewDeploymentController(
 		ctx.InformerFactory.Apps().V1().Deployments(),
 		ctx.InformerFactory.Apps().V1().ReplicaSets(),

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

@@ -21,11 +21,10 @@ limitations under the License.
 package app
 
 import (
-	"net/http"
-
 	"k8s.io/apimachinery/pkg/runtime/schema"
 	"k8s.io/client-go/dynamic"
 	"k8s.io/client-go/scale"
+	"k8s.io/controller-manager/controller"
 	"k8s.io/kubernetes/pkg/controller/podautoscaler"
 	"k8s.io/kubernetes/pkg/controller/podautoscaler/metrics"
 
@@ -34,7 +33,7 @@ import (
 	"k8s.io/metrics/pkg/client/external_metrics"
 )
 
-func startHPAController(ctx ControllerContext) (http.Handler, bool, error) {
+func startHPAController(ctx ControllerContext) (controller.Interface, bool, error) {
 	if !ctx.AvailableResources[schema.GroupVersionResource{Group: "autoscaling", Version: "v1", Resource: "horizontalpodautoscalers"}] {
 		return nil, false, nil
 	}
@@ -42,7 +41,7 @@ func startHPAController(ctx ControllerContext) (http.Handler, bool, error) {
 	return startHPAControllerWithRESTClient(ctx)
 }
 
-func startHPAControllerWithRESTClient(ctx ControllerContext) (http.Handler, bool, error) {
+func startHPAControllerWithRESTClient(ctx ControllerContext) (controller.Interface, bool, error) {
 	clientConfig := ctx.ClientBuilder.ConfigOrDie("horizontal-pod-autoscaler")
 	hpaClient := ctx.ClientBuilder.ClientOrDie("horizontal-pod-autoscaler")
 
@@ -62,7 +61,7 @@ func startHPAControllerWithRESTClient(ctx ControllerContext) (http.Handler, bool
 	return startHPAControllerWithMetricsClient(ctx, metricsClient)
 }
 
-func startHPAControllerWithMetricsClient(ctx ControllerContext, metricsClient metrics.MetricsClient) (http.Handler, bool, error) {
+func startHPAControllerWithMetricsClient(ctx ControllerContext, metricsClient metrics.MetricsClient) (controller.Interface, bool, error) {
 	hpaClient := ctx.ClientBuilder.ClientOrDie("horizontal-pod-autoscaler")
 	hpaClientConfig := ctx.ClientBuilder.ConfigOrDie("horizontal-pod-autoscaler")
 

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

@@ -22,15 +22,15 @@ package app
 
 import (
 	"fmt"
-	"net/http"
 
 	utilfeature "k8s.io/apiserver/pkg/util/feature"
+	"k8s.io/controller-manager/controller"
 	"k8s.io/kubernetes/pkg/controller/cronjob"
 	"k8s.io/kubernetes/pkg/controller/job"
 	kubefeatures "k8s.io/kubernetes/pkg/features"
 )
 
-func startJobController(ctx ControllerContext) (http.Handler, bool, error) {
+func startJobController(ctx ControllerContext) (controller.Interface, bool, error) {
 	go job.NewController(
 		ctx.InformerFactory.Core().V1().Pods(),
 		ctx.InformerFactory.Batch().V1().Jobs(),
@@ -39,7 +39,7 @@ func startJobController(ctx ControllerContext) (http.Handler, bool, error) {
 	return nil, true, nil
 }
 
-func startCronJobController(ctx ControllerContext) (http.Handler, bool, error) {
+func startCronJobController(ctx ControllerContext) (controller.Interface, bool, error) {
 	if utilfeature.DefaultFeatureGate.Enabled(kubefeatures.CronJobControllerV2) {
 		cj2c, err := cronjob.NewControllerV2(ctx.InformerFactory.Batch().V1().Jobs(),
 			ctx.InformerFactory.Batch().V1().CronJobs(),

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

@@ -19,12 +19,11 @@ package app
 import (
 	"fmt"
 
-	"net/http"
+	"k8s.io/controller-manager/controller"
-
 	"k8s.io/kubernetes/pkg/controller/bootstrap"
 )
 
-func startBootstrapSignerController(ctx ControllerContext) (http.Handler, bool, error) {
+func startBootstrapSignerController(ctx ControllerContext) (controller.Interface, bool, error) {
 	bsc, err := bootstrap.NewSigner(
 		ctx.ClientBuilder.ClientOrDie("bootstrap-signer"),
 		ctx.InformerFactory.Core().V1().Secrets(),
@@ -38,7 +37,7 @@ func startBootstrapSignerController(ctx ControllerContext) (http.Handler, bool,
 	return nil, true, nil
 }
 
-func startTokenCleanerController(ctx ControllerContext) (http.Handler, bool, error) {
+func startTokenCleanerController(ctx ControllerContext) (controller.Interface, bool, error) {
 	tcc, err := bootstrap.NewTokenCleaner(
 		ctx.ClientBuilder.ClientOrDie("token-cleaner"),
 		ctx.InformerFactory.Core().V1().Secrets(),

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

@@ -22,8 +22,8 @@ package app
 
 import (
 	"fmt"
-	"net/http"
 
+	"k8s.io/controller-manager/controller"
 	"k8s.io/klog/v2"
 	"k8s.io/kubernetes/pkg/controller/certificates/approver"
 	"k8s.io/kubernetes/pkg/controller/certificates/cleaner"
@@ -32,7 +32,7 @@ import (
 	csrsigningconfig "k8s.io/kubernetes/pkg/controller/certificates/signer/config"
 )
 
-func startCSRSigningController(ctx ControllerContext) (http.Handler, bool, error) {
+func startCSRSigningController(ctx ControllerContext) (controller.Interface, bool, error) {
 	missingSingleSigningFile := ctx.ComponentConfig.CSRSigningController.ClusterSigningCertFile == "" || ctx.ComponentConfig.CSRSigningController.ClusterSigningKeyFile == ""
 	if missingSingleSigningFile && !anySpecificFilesSet(ctx.ComponentConfig.CSRSigningController) {
 		klog.V(2).Info("skipping CSR signer controller because no csr cert/key was specified")
@@ -147,7 +147,7 @@ func getLegacyUnknownSignerFiles(config csrsigningconfig.CSRSigningControllerCon
 	return config.ClusterSigningCertFile, config.ClusterSigningKeyFile
 }
 
-func startCSRApprovingController(ctx ControllerContext) (http.Handler, bool, error) {
+func startCSRApprovingController(ctx ControllerContext) (controller.Interface, bool, error) {
 	approver := approver.NewCSRApprovingController(
 		ctx.ClientBuilder.ClientOrDie("certificate-controller"),
 		ctx.InformerFactory.Certificates().V1().CertificateSigningRequests(),
@@ -157,7 +157,7 @@ func startCSRApprovingController(ctx ControllerContext) (http.Handler, bool, err
 	return nil, true, nil
 }
 
-func startCSRCleanerController(ctx ControllerContext) (http.Handler, bool, error) {
+func startCSRCleanerController(ctx ControllerContext) (controller.Interface, bool, error) {
 	cleaner := cleaner.NewCSRCleanerController(
 		ctx.ClientBuilder.ClientOrDie("certificate-controller").CertificatesV1().CertificateSigningRequests(),
 		ctx.InformerFactory.Certificates().V1().CertificateSigningRequests(),
@@ -166,7 +166,7 @@ func startCSRCleanerController(ctx ControllerContext) (http.Handler, bool, error
 	return nil, true, nil
 }
 
-func startRootCACertPublisher(ctx ControllerContext) (http.Handler, bool, error) {
+func startRootCACertPublisher(ctx ControllerContext) (controller.Interface, bool, error) {
 	var (
 		rootCA []byte
 		err    error

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

@@ -59,6 +59,7 @@ import (
 	"k8s.io/component-base/version"
 	"k8s.io/component-base/version/verflag"
 	genericcontrollermanager "k8s.io/controller-manager/app"
+	"k8s.io/controller-manager/controller"
 	"k8s.io/controller-manager/pkg/clientbuilder"
 	"k8s.io/controller-manager/pkg/informerfactory"
 	"k8s.io/controller-manager/pkg/leadermigration"
@@ -262,7 +263,7 @@ func Run(c *config.CompletedConfig, stopCh <-chan struct{}) error {
 
 		// Wrap saTokenControllerInitFunc to signal readiness for migration after starting
 		//  the controller.
-		startSATokenController = func(ctx ControllerContext) (http.Handler, bool, error) {
+		startSATokenController = func(ctx ControllerContext) (controller.Interface, bool, error) {
 			defer close(leaderMigrator.MigrationReady)
 			return saTokenControllerInitFunc(ctx)
 		}
@@ -367,10 +368,14 @@ func (c ControllerContext) IsControllerEnabled(name string) bool {
 	return genericcontrollermanager.IsControllerEnabled(name, ControllersDisabledByDefault, c.ComponentConfig.Generic.Controllers)
 }
 
-// InitFunc is used to launch a particular controller.  It may run additional "should I activate checks".
+// InitFunc is used to launch a particular controller. It returns a controller
+// that can optionally implement other interfaces so that the controller manager
+// can support the requested features.
+// The returned controller may be nil, which will be considered an anonymous controller
+// that requests no additional features from the controller manager.
 // Any error returned will cause the controller process to `Fatal`
 // The bool indicates whether the controller was enabled.
-type InitFunc func(ctx ControllerContext) (debuggingHandler http.Handler, enabled bool, err error)
+type InitFunc func(ctx ControllerContext) (controller controller.Interface, enabled bool, err error)
 
 // ControllerInitializersFunc is used to create a collection of initializers
 //  given the loopMode.
@@ -560,7 +565,7 @@ func StartControllers(ctx ControllerContext, startSATokenController InitFunc, co
 		time.Sleep(wait.Jitter(ctx.ComponentConfig.Generic.ControllerStartInterval.Duration, ControllerStartJitter))
 
 		klog.V(1).Infof("Starting %q", controllerName)
-		debugHandler, started, err := initFn(ctx)
+		ctrl, started, err := initFn(ctx)
 		if err != nil {
 			klog.Errorf("Error starting %q", controllerName)
 			return err
@@ -569,10 +574,16 @@ func StartControllers(ctx ControllerContext, startSATokenController InitFunc, co
 			klog.Warningf("Skipping %q", controllerName)
 			continue
 		}
-		if debugHandler != nil && unsecuredMux != nil {
+		if ctrl != nil {
-			basePath := "/debug/controllers/" + controllerName
+			// check if the controller supports and requests a debugHandler
-			unsecuredMux.UnlistedHandle(basePath, http.StripPrefix(basePath, debugHandler))
+			// and it needs the unsecuredMux to mount the handler onto.
-			unsecuredMux.UnlistedHandlePrefix(basePath+"/", http.StripPrefix(basePath, debugHandler))
+			if debuggable, ok := ctrl.(controller.Debuggable); ok && unsecuredMux != nil {
+				if debugHandler := debuggable.DebuggingHandler(); debugHandler != nil {
+					basePath := "/debug/controllers/" + controllerName
+					unsecuredMux.UnlistedHandle(basePath, http.StripPrefix(basePath, debugHandler))
+					unsecuredMux.UnlistedHandlePrefix(basePath+"/", http.StripPrefix(basePath, debugHandler))
+				}
+			}
 		}
 		klog.Infof("Started %q", controllerName)
 	}
@@ -587,7 +598,7 @@ type serviceAccountTokenControllerStarter struct {
 	rootClientBuilder clientbuilder.ControllerClientBuilder
 }
 
-func (c serviceAccountTokenControllerStarter) startServiceAccountTokenController(ctx ControllerContext) (http.Handler, bool, error) {
+func (c serviceAccountTokenControllerStarter) startServiceAccountTokenController(ctx ControllerContext) (controller.Interface, bool, error) {
 	if !ctx.IsControllerEnabled(saTokenControllerName) {
 		klog.Warningf("%q is disabled", saTokenControllerName)
 		return nil, false, nil

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

@@ -24,7 +24,6 @@ import (
 	"errors"
 	"fmt"
 	"net"
-	"net/http"
 	"strings"
 	"time"
 
@@ -41,9 +40,10 @@ import (
 	routecontroller "k8s.io/cloud-provider/controllers/route"
 	servicecontroller "k8s.io/cloud-provider/controllers/service"
 	"k8s.io/component-base/metrics/prometheus/ratelimiter"
+	"k8s.io/controller-manager/controller"
 	csitrans "k8s.io/csi-translation-lib"
 	"k8s.io/kubernetes/cmd/kube-controller-manager/app/options"
-	"k8s.io/kubernetes/pkg/controller"
+	pkgcontroller "k8s.io/kubernetes/pkg/controller"
 	endpointcontroller "k8s.io/kubernetes/pkg/controller/endpoint"
 	"k8s.io/kubernetes/pkg/controller/garbagecollector"
 	namespacecontroller "k8s.io/kubernetes/pkg/controller/namespace"
@@ -77,7 +77,7 @@ const (
 	defaultNodeMaskCIDRIPv6 = 64
 )
 
-func startServiceController(ctx ControllerContext) (http.Handler, bool, error) {
+func startServiceController(ctx ControllerContext) (controller.Interface, bool, error) {
 	serviceController, err := servicecontroller.New(
 		ctx.Cloud,
 		ctx.ClientBuilder.ClientOrDie("service-controller"),
@@ -95,7 +95,7 @@ func startServiceController(ctx ControllerContext) (http.Handler, bool, error) {
 	return nil, true, nil
 }
 
-func startNodeIpamController(ctx ControllerContext) (http.Handler, bool, error) {
+func startNodeIpamController(ctx ControllerContext) (controller.Interface, bool, error) {
 	var serviceCIDR *net.IPNet
 	var secondaryServiceCIDR *net.IPNet
 
@@ -192,7 +192,7 @@ func startNodeIpamController(ctx ControllerContext) (http.Handler, bool, error)
 	return nil, true, nil
 }
 
-func startNodeLifecycleController(ctx ControllerContext) (http.Handler, bool, error) {
+func startNodeLifecycleController(ctx ControllerContext) (controller.Interface, bool, error) {
 	lifecycleController, err := lifecyclecontroller.NewNodeLifecycleController(
 		ctx.InformerFactory.Coordination().V1().Leases(),
 		ctx.InformerFactory.Core().V1().Pods(),
@@ -217,7 +217,7 @@ func startNodeLifecycleController(ctx ControllerContext) (http.Handler, bool, er
 	return nil, true, nil
 }
 
-func startCloudNodeLifecycleController(ctx ControllerContext) (http.Handler, bool, error) {
+func startCloudNodeLifecycleController(ctx ControllerContext) (controller.Interface, bool, error) {
 	cloudNodeLifecycleController, err := cloudnodelifecyclecontroller.NewCloudNodeLifecycleController(
 		ctx.InformerFactory.Core().V1().Nodes(),
 		// cloud node lifecycle controller uses existing cluster role from node-controller
@@ -236,7 +236,7 @@ func startCloudNodeLifecycleController(ctx ControllerContext) (http.Handler, boo
 	return nil, true, nil
 }
 
-func startRouteController(ctx ControllerContext) (http.Handler, bool, error) {
+func startRouteController(ctx ControllerContext) (controller.Interface, bool, error) {
 	if !ctx.ComponentConfig.KubeCloudShared.AllocateNodeCIDRs || !ctx.ComponentConfig.KubeCloudShared.ConfigureCloudRoutes {
 		klog.Infof("Will not configure cloud provider routes for allocate-node-cidrs: %v, configure-cloud-routes: %v.", ctx.ComponentConfig.KubeCloudShared.AllocateNodeCIDRs, ctx.ComponentConfig.KubeCloudShared.ConfigureCloudRoutes)
 		return nil, false, nil
@@ -281,7 +281,7 @@ func startRouteController(ctx ControllerContext) (http.Handler, bool, error) {
 	return nil, true, nil
 }
 
-func startPersistentVolumeBinderController(ctx ControllerContext) (http.Handler, bool, error) {
+func startPersistentVolumeBinderController(ctx ControllerContext) (controller.Interface, bool, error) {
 	plugins, err := ProbeControllerVolumePlugins(ctx.Cloud, ctx.ComponentConfig.PersistentVolumeBinderController.VolumeConfiguration)
 	if err != nil {
 		return nil, true, fmt.Errorf("failed to probe volume plugins when starting persistentvolume controller: %v", err)
@@ -314,7 +314,7 @@ func startPersistentVolumeBinderController(ctx ControllerContext) (http.Handler,
 	return nil, true, nil
 }
 
-func startAttachDetachController(ctx ControllerContext) (http.Handler, bool, error) {
+func startAttachDetachController(ctx ControllerContext) (controller.Interface, bool, error) {
 	if ctx.ComponentConfig.AttachDetachController.ReconcilerSyncLoopPeriod.Duration < time.Second {
 		return nil, true, fmt.Errorf("duration time must be greater than one second as set via command line option reconcile-sync-loop-period")
 	}
@@ -359,7 +359,7 @@ func startAttachDetachController(ctx ControllerContext) (http.Handler, bool, err
 	return nil, true, nil
 }
 
-func startVolumeExpandController(ctx ControllerContext) (http.Handler, bool, error) {
+func startVolumeExpandController(ctx ControllerContext) (controller.Interface, bool, error) {
 	if utilfeature.DefaultFeatureGate.Enabled(features.ExpandPersistentVolumes) {
 		plugins, err := ProbeExpandableVolumePlugins(ctx.ComponentConfig.PersistentVolumeBinderController.VolumeConfiguration)
 		if err != nil {
@@ -392,7 +392,7 @@ func startVolumeExpandController(ctx ControllerContext) (http.Handler, bool, err
 	return nil, false, nil
 }
 
-func startEphemeralVolumeController(ctx ControllerContext) (http.Handler, bool, error) {
+func startEphemeralVolumeController(ctx ControllerContext) (controller.Interface, bool, error) {
 	if utilfeature.DefaultFeatureGate.Enabled(features.GenericEphemeralVolume) {
 		ephemeralController, err := ephemeral.NewController(
 			ctx.ClientBuilder.ClientOrDie("ephemeral-volume-controller"),
@@ -407,7 +407,7 @@ func startEphemeralVolumeController(ctx ControllerContext) (http.Handler, bool,
 	return nil, false, nil
 }
 
-func startEndpointController(ctx ControllerContext) (http.Handler, bool, error) {
+func startEndpointController(ctx ControllerContext) (controller.Interface, bool, error) {
 	go endpointcontroller.NewEndpointController(
 		ctx.InformerFactory.Core().V1().Pods(),
 		ctx.InformerFactory.Core().V1().Services(),
@@ -418,7 +418,7 @@ func startEndpointController(ctx ControllerContext) (http.Handler, bool, error)
 	return nil, true, nil
 }
 
-func startReplicationController(ctx ControllerContext) (http.Handler, bool, error) {
+func startReplicationController(ctx ControllerContext) (controller.Interface, bool, error) {
 	go replicationcontroller.NewReplicationManager(
 		ctx.InformerFactory.Core().V1().Pods(),
 		ctx.InformerFactory.Core().V1().ReplicationControllers(),
@@ -428,7 +428,7 @@ func startReplicationController(ctx ControllerContext) (http.Handler, bool, erro
 	return nil, true, nil
 }
 
-func startPodGCController(ctx ControllerContext) (http.Handler, bool, error) {
+func startPodGCController(ctx ControllerContext) (controller.Interface, bool, error) {
 	go podgc.NewPodGC(
 		ctx.ClientBuilder.ClientOrDie("pod-garbage-collector"),
 		ctx.InformerFactory.Core().V1().Pods(),
@@ -438,7 +438,7 @@ func startPodGCController(ctx ControllerContext) (http.Handler, bool, error) {
 	return nil, true, nil
 }
 
-func startResourceQuotaController(ctx ControllerContext) (http.Handler, bool, error) {
+func startResourceQuotaController(ctx ControllerContext) (controller.Interface, bool, error) {
 	resourceQuotaControllerClient := ctx.ClientBuilder.ClientOrDie("resourcequota-controller")
 	resourceQuotaControllerDiscoveryClient := ctx.ClientBuilder.DiscoveryClientOrDie("resourcequota-controller")
 	discoveryFunc := resourceQuotaControllerDiscoveryClient.ServerPreferredNamespacedResources
@@ -448,7 +448,7 @@ func startResourceQuotaController(ctx ControllerContext) (http.Handler, bool, er
 	resourceQuotaControllerOptions := &resourcequotacontroller.ControllerOptions{
 		QuotaClient:               resourceQuotaControllerClient.CoreV1(),
 		ResourceQuotaInformer:     ctx.InformerFactory.Core().V1().ResourceQuotas(),
-		ResyncPeriod:              controller.StaticResyncPeriodFunc(ctx.ComponentConfig.ResourceQuotaController.ResourceQuotaSyncPeriod.Duration),
+		ResyncPeriod:              pkgcontroller.StaticResyncPeriodFunc(ctx.ComponentConfig.ResourceQuotaController.ResourceQuotaSyncPeriod.Duration),
 		InformerFactory:           ctx.ObjectOrMetadataInformerFactory,
 		ReplenishmentResyncPeriod: ctx.ResyncPeriod,
 		DiscoveryFunc:             discoveryFunc,
@@ -474,7 +474,7 @@ func startResourceQuotaController(ctx ControllerContext) (http.Handler, bool, er
 	return nil, true, nil
 }
 
-func startNamespaceController(ctx ControllerContext) (http.Handler, bool, error) {
+func startNamespaceController(ctx ControllerContext) (controller.Interface, bool, error) {
 	// the namespace cleanup controller is very chatty.  It makes lots of discovery calls and then it makes lots of delete calls
 	// the ratelimiter negatively affects its speed.  Deleting 100 total items in a namespace (that's only a few of each resource
 	// including events), takes ~10 seconds by default.
@@ -485,7 +485,7 @@ func startNamespaceController(ctx ControllerContext) (http.Handler, bool, error)
 	return startModifiedNamespaceController(ctx, namespaceKubeClient, nsKubeconfig)
 }
 
-func startModifiedNamespaceController(ctx ControllerContext, namespaceKubeClient clientset.Interface, nsKubeconfig *restclient.Config) (http.Handler, bool, error) {
+func startModifiedNamespaceController(ctx ControllerContext, namespaceKubeClient clientset.Interface, nsKubeconfig *restclient.Config) (controller.Interface, bool, error) {
 
 	metadataClient, err := metadata.NewForConfig(nsKubeconfig)
 	if err != nil {
@@ -507,7 +507,7 @@ func startModifiedNamespaceController(ctx ControllerContext, namespaceKubeClient
 	return nil, true, nil
 }
 
-func startServiceAccountController(ctx ControllerContext) (http.Handler, bool, error) {
+func startServiceAccountController(ctx ControllerContext) (controller.Interface, bool, error) {
 	sac, err := serviceaccountcontroller.NewServiceAccountsController(
 		ctx.InformerFactory.Core().V1().ServiceAccounts(),
 		ctx.InformerFactory.Core().V1().Namespaces(),
@@ -521,7 +521,7 @@ func startServiceAccountController(ctx ControllerContext) (http.Handler, bool, e
 	return nil, true, nil
 }
 
-func startTTLController(ctx ControllerContext) (http.Handler, bool, error) {
+func startTTLController(ctx ControllerContext) (controller.Interface, bool, error) {
 	go ttlcontroller.NewTTLController(
 		ctx.InformerFactory.Core().V1().Nodes(),
 		ctx.ClientBuilder.ClientOrDie("ttl-controller"),
@@ -529,7 +529,7 @@ func startTTLController(ctx ControllerContext) (http.Handler, bool, error) {
 	return nil, true, nil
 }
 
-func startGarbageCollectorController(ctx ControllerContext) (http.Handler, bool, error) {
+func startGarbageCollectorController(ctx ControllerContext) (controller.Interface, bool, error) {
 	if !ctx.ComponentConfig.GarbageCollectorController.EnableGarbageCollector {
 		return nil, false, nil
 	}
@@ -567,10 +567,10 @@ func startGarbageCollectorController(ctx ControllerContext) (http.Handler, bool,
 	// the garbage collector.
 	go garbageCollector.Sync(discoveryClient, 30*time.Second, ctx.Stop)
 
-	return garbagecollector.NewDebugHandler(garbageCollector), true, nil
+	return garbageCollector, true, nil
 }
 
-func startPVCProtectionController(ctx ControllerContext) (http.Handler, bool, error) {
+func startPVCProtectionController(ctx ControllerContext) (controller.Interface, bool, error) {
 	pvcProtectionController, err := pvcprotection.NewPVCProtectionController(
 		ctx.InformerFactory.Core().V1().PersistentVolumeClaims(),
 		ctx.InformerFactory.Core().V1().Pods(),
@@ -585,7 +585,7 @@ func startPVCProtectionController(ctx ControllerContext) (http.Handler, bool, er
 	return nil, true, nil
 }
 
-func startPVProtectionController(ctx ControllerContext) (http.Handler, bool, error) {
+func startPVProtectionController(ctx ControllerContext) (controller.Interface, bool, error) {
 	go pvprotection.NewPVProtectionController(
 		ctx.InformerFactory.Core().V1().PersistentVolumes(),
 		ctx.ClientBuilder.ClientOrDie("pv-protection-controller"),
@@ -594,7 +594,7 @@ func startPVProtectionController(ctx ControllerContext) (http.Handler, bool, err
 	return nil, true, nil
 }
 
-func startTTLAfterFinishedController(ctx ControllerContext) (http.Handler, bool, error) {
+func startTTLAfterFinishedController(ctx ControllerContext) (controller.Interface, bool, error) {
 	if !utilfeature.DefaultFeatureGate.Enabled(features.TTLAfterFinished) {
 		return nil, false, nil
 	}
@@ -672,7 +672,7 @@ func getNodeCIDRMaskSizes(clusterCIDRs []*net.IPNet, maskSizeIPv4, maskSizeIPv6
 	return nodeMaskCIDRs
 }
 
-func startStorageVersionGCController(ctx ControllerContext) (http.Handler, bool, error) {
+func startStorageVersionGCController(ctx ControllerContext) (controller.Interface, bool, error) {
 	go storageversiongc.NewStorageVersionGC(
 		ctx.ClientBuilder.ClientOrDie("storage-version-garbage-collector"),
 		ctx.InformerFactory.Coordination().V1().Leases(),

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

@@ -17,7 +17,6 @@ limitations under the License.
 package app
 
 import (
-	"net/http"
 	"testing"
 	"time"
 
@@ -28,6 +27,7 @@ import (
 	clientset "k8s.io/client-go/kubernetes"
 	fakeclientset "k8s.io/client-go/kubernetes/fake"
 	restclient "k8s.io/client-go/rest"
+	"k8s.io/controller-manager/controller"
 )
 
 // TestClientBuilder inherits ClientBuilder and can accept a given fake clientset.
@@ -104,7 +104,7 @@ func possibleDiscoveryResource() []*metav1.APIResourceList {
 	}
 }
 
-type controllerInitFunc func(ControllerContext) (http.Handler, bool, error)
+type controllerInitFunc func(ControllerContext) (controller.Interface, bool, error)
 
 func TestController_DiscoveryError(t *testing.T) {
 	controllerInitFuncMap := map[string]controllerInitFunc{

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

@@ -21,13 +21,12 @@ limitations under the License.
 package app
 
 import (
-	"net/http"
+	"k8s.io/controller-manager/controller"
-
 	endpointslicecontroller "k8s.io/kubernetes/pkg/controller/endpointslice"
 	endpointslicemirroringcontroller "k8s.io/kubernetes/pkg/controller/endpointslicemirroring"
 )
 
-func startEndpointSliceController(ctx ControllerContext) (http.Handler, bool, error) {
+func startEndpointSliceController(ctx ControllerContext) (controller.Interface, bool, error) {
 	go endpointslicecontroller.NewController(
 		ctx.InformerFactory.Core().V1().Pods(),
 		ctx.InformerFactory.Core().V1().Services(),
@@ -40,7 +39,7 @@ func startEndpointSliceController(ctx ControllerContext) (http.Handler, bool, er
 	return nil, true, nil
 }
 
-func startEndpointSliceMirroringController(ctx ControllerContext) (http.Handler, bool, error) {
+func startEndpointSliceMirroringController(ctx ControllerContext) (controller.Interface, bool, error) {
 	go endpointslicemirroringcontroller.NewController(
 		ctx.InformerFactory.Core().V1().Endpoints(),
 		ctx.InformerFactory.Discovery().V1().EndpointSlices(),

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

@@ -21,18 +21,17 @@ limitations under the License.
 package app
 
 import (
-	"net/http"
-
 	"k8s.io/klog/v2"
 
 	utilfeature "k8s.io/apiserver/pkg/util/feature"
 	"k8s.io/client-go/dynamic"
 	"k8s.io/client-go/scale"
+	"k8s.io/controller-manager/controller"
 	"k8s.io/kubernetes/pkg/controller/disruption"
 	kubefeatures "k8s.io/kubernetes/pkg/features"
 )
 
-func startDisruptionController(ctx ControllerContext) (http.Handler, bool, error) {
+func startDisruptionController(ctx ControllerContext) (controller.Interface, bool, error) {
 	if !utilfeature.DefaultFeatureGate.Enabled(kubefeatures.PodDisruptionBudget) {
 		klog.InfoS("Refusing to start disruption because the PodDisruptionBudget feature is disabled")
 		return nil, false, nil

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

@@ -17,13 +17,12 @@ limitations under the License.
 package app
 
 import (
-	"net/http"
-
 	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/controller-manager/controller"
 	"k8s.io/kubernetes/pkg/controller/clusterroleaggregation"
 )
 
-func startClusterRoleAggregrationController(ctx ControllerContext) (http.Handler, bool, error) {
+func startClusterRoleAggregrationController(ctx ControllerContext) (controller.Interface, bool, error) {
 	if !ctx.AvailableResources[schema.GroupVersionResource{Group: "rbac.authorization.k8s.io", Version: "v1", Resource: "clusterroles"}] {
 		return nil, false, nil
 	}

pkg/controller/garbagecollector/dump.go

@@ -281,3 +281,7 @@ func (h *debugHTTPHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 	w.Write(data)
 	w.WriteHeader(http.StatusOK)
 }
+
+func (gc *GarbageCollector) DebuggingHandler() http.Handler {
+	return NewDebugHandler(gc)
+}

pkg/controller/garbagecollector/garbagecollector.go

@@ -43,6 +43,7 @@ import (
 	"k8s.io/client-go/tools/cache"
 	"k8s.io/client-go/tools/record"
 	"k8s.io/client-go/util/workqueue"
+	"k8s.io/controller-manager/controller"
 	"k8s.io/controller-manager/pkg/informerfactory"
 	"k8s.io/kubernetes/pkg/controller/apis/config/scheme"
 
@@ -78,6 +79,9 @@ type GarbageCollector struct {
 	workerLock sync.RWMutex
 }
 
+var _ controller.Interface = (*GarbageCollector)(nil)
+var _ controller.Debuggable = (*GarbageCollector)(nil)
+
 // NewGarbageCollector creates a new GarbageCollector.
 func NewGarbageCollector(
 	kubeClient clientset.Interface,
@@ -726,3 +730,7 @@ func GetDeletableResources(discoveryClient discovery.ServerResourcesInterface) m
 
 	return deletableGroupVersionResources
 }
+
+func (gc *GarbageCollector) Name() string {
+	return "garbagecollector"
+}

staging/src/k8s.io/cloud-provider/app/controllermanager.go

@@ -21,7 +21,6 @@ import (
 	"flag"
 	"fmt"
 	"math/rand"
-	"net/http"
 	"os"
 	"time"
 
@@ -50,6 +49,7 @@ import (
 	"k8s.io/component-base/version"
 	"k8s.io/component-base/version/verflag"
 	genericcontrollermanager "k8s.io/controller-manager/app"
+	"k8s.io/controller-manager/controller"
 	"k8s.io/controller-manager/pkg/clientbuilder"
 	"k8s.io/controller-manager/pkg/informerfactory"
 	"k8s.io/controller-manager/pkg/leadermigration"
@@ -302,10 +302,14 @@ func startControllers(cloud cloudprovider.Interface, ctx genericcontrollermanage
 // InitCloudFunc is used to initialize cloud
 type InitCloudFunc func(config *cloudcontrollerconfig.CompletedConfig) cloudprovider.Interface
 
-// InitFunc is used to launch a particular controller.  It may run additional "should I activate checks".
+// InitFunc is used to launch a particular controller. It returns a controller
+// that can optionally implement other interfaces so that the controller manager
+// can support the requested features.
+// The returned controller may be nil, which will be considered an anonymous controller
+// that requests no additional features from the controller manager.
 // Any error returned will cause the controller process to `Fatal`
 // The bool indicates whether the controller was enabled.
-type InitFunc func(ctx genericcontrollermanager.ControllerContext) (debuggingHandler http.Handler, enabled bool, err error)
+type InitFunc func(ctx genericcontrollermanager.ControllerContext) (controller controller.Interface, enabled bool, err error)
 
 // InitFuncConstructor is used to construct InitFunc
 type InitFuncConstructor func(initcontext ControllerInitContext, completedConfig *cloudcontrollerconfig.CompletedConfig, cloud cloudprovider.Interface) InitFunc
@@ -340,28 +344,28 @@ type ControllerInitContext struct {
 
 // StartCloudNodeControllerWrapper is used to take cloud cofig as input and start cloud node controller
 func StartCloudNodeControllerWrapper(initContext ControllerInitContext, completedConfig *cloudcontrollerconfig.CompletedConfig, cloud cloudprovider.Interface) InitFunc {
-	return func(ctx genericcontrollermanager.ControllerContext) (http.Handler, bool, error) {
+	return func(ctx genericcontrollermanager.ControllerContext) (controller.Interface, bool, error) {
 		return startCloudNodeController(initContext, completedConfig, cloud, ctx.Stop)
 	}
 }
 
 // StartCloudNodeLifecycleControllerWrapper is used to take cloud cofig as input and start cloud node lifecycle controller
 func StartCloudNodeLifecycleControllerWrapper(initContext ControllerInitContext, completedConfig *cloudcontrollerconfig.CompletedConfig, cloud cloudprovider.Interface) InitFunc {
-	return func(ctx genericcontrollermanager.ControllerContext) (http.Handler, bool, error) {
+	return func(ctx genericcontrollermanager.ControllerContext) (controller.Interface, bool, error) {
 		return startCloudNodeLifecycleController(initContext, completedConfig, cloud, ctx.Stop)
 	}
 }
 
 // StartServiceControllerWrapper is used to take cloud cofig as input and start service controller
 func StartServiceControllerWrapper(initContext ControllerInitContext, completedConfig *cloudcontrollerconfig.CompletedConfig, cloud cloudprovider.Interface) InitFunc {
-	return func(ctx genericcontrollermanager.ControllerContext) (http.Handler, bool, error) {
+	return func(ctx genericcontrollermanager.ControllerContext) (controller.Interface, bool, error) {
 		return startServiceController(initContext, completedConfig, cloud, ctx.Stop)
 	}
 }
 
 // StartRouteControllerWrapper is used to take cloud cofig as input and start route controller
 func StartRouteControllerWrapper(initContext ControllerInitContext, completedConfig *cloudcontrollerconfig.CompletedConfig, cloud cloudprovider.Interface) InitFunc {
-	return func(ctx genericcontrollermanager.ControllerContext) (http.Handler, bool, error) {
+	return func(ctx genericcontrollermanager.ControllerContext) (controller.Interface, bool, error) {
 		return startRouteController(initContext, completedConfig, cloud, ctx.Stop)
 	}
 }

staging/src/k8s.io/cloud-provider/app/core.go

@@ -23,7 +23,6 @@ package app
 import (
 	"fmt"
 	"net"
-	"net/http"
 	"strings"
 
 	cloudprovider "k8s.io/cloud-provider"
@@ -32,6 +31,7 @@ import (
 	cloudnodelifecyclecontroller "k8s.io/cloud-provider/controllers/nodelifecycle"
 	routecontroller "k8s.io/cloud-provider/controllers/route"
 	servicecontroller "k8s.io/cloud-provider/controllers/service"
+	"k8s.io/controller-manager/controller"
 	"k8s.io/controller-manager/pkg/features"
 	"k8s.io/klog/v2"
 	netutils "k8s.io/utils/net"
@@ -39,7 +39,7 @@ import (
 	utilfeature "k8s.io/apiserver/pkg/util/feature"
 )
 
-func startCloudNodeController(initContext ControllerInitContext, ctx *config.CompletedConfig, cloud cloudprovider.Interface, stopCh <-chan struct{}) (http.Handler, bool, error) {
+func startCloudNodeController(initContext ControllerInitContext, ctx *config.CompletedConfig, cloud cloudprovider.Interface, stopCh <-chan struct{}) (controller.Interface, bool, error) {
 	// Start the CloudNodeController
 	nodeController, err := cloudnodecontroller.NewCloudNodeController(
 		ctx.SharedInformers.Core().V1().Nodes(),
@@ -58,7 +58,7 @@ func startCloudNodeController(initContext ControllerInitContext, ctx *config.Com
 	return nil, true, nil
 }
 
-func startCloudNodeLifecycleController(initContext ControllerInitContext, ctx *config.CompletedConfig, cloud cloudprovider.Interface, stopCh <-chan struct{}) (http.Handler, bool, error) {
+func startCloudNodeLifecycleController(initContext ControllerInitContext, ctx *config.CompletedConfig, cloud cloudprovider.Interface, stopCh <-chan struct{}) (controller.Interface, bool, error) {
 	// Start the cloudNodeLifecycleController
 	cloudNodeLifecycleController, err := cloudnodelifecyclecontroller.NewCloudNodeLifecycleController(
 		ctx.SharedInformers.Core().V1().Nodes(),
@@ -77,7 +77,7 @@ func startCloudNodeLifecycleController(initContext ControllerInitContext, ctx *c
 	return nil, true, nil
 }
 
-func startServiceController(initContext ControllerInitContext, ctx *config.CompletedConfig, cloud cloudprovider.Interface, stopCh <-chan struct{}) (http.Handler, bool, error) {
+func startServiceController(initContext ControllerInitContext, ctx *config.CompletedConfig, cloud cloudprovider.Interface, stopCh <-chan struct{}) (controller.Interface, bool, error) {
 	// Start the service controller
 	serviceController, err := servicecontroller.New(
 		cloud,
@@ -98,7 +98,7 @@ func startServiceController(initContext ControllerInitContext, ctx *config.Compl
 	return nil, true, nil
 }
 
-func startRouteController(initContext ControllerInitContext, ctx *config.CompletedConfig, cloud cloudprovider.Interface, stopCh <-chan struct{}) (http.Handler, bool, error) {
+func startRouteController(initContext ControllerInitContext, ctx *config.CompletedConfig, cloud cloudprovider.Interface, stopCh <-chan struct{}) (controller.Interface, bool, error) {
 	if !ctx.ComponentConfig.KubeCloudShared.ConfigureCloudRoutes {
 		klog.Infof("Will not configure cloud provider routes, --configure-cloud-routes: %v", ctx.ComponentConfig.KubeCloudShared.ConfigureCloudRoutes)
 		return nil, false, nil

vendor/modules.txt

@@ -1969,6 +1969,7 @@ k8s.io/controller-manager/app
 k8s.io/controller-manager/config
 k8s.io/controller-manager/config/v1alpha1
 k8s.io/controller-manager/config/v1beta1
+k8s.io/controller-manager/controller
 k8s.io/controller-manager/options
 k8s.io/controller-manager/pkg/clientbuilder
 k8s.io/controller-manager/pkg/features