controller-manager support number of garbage collector workers to be configurable

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

@@ -468,7 +468,7 @@ func StartControllers(s *options.CMServer, kubeClient *client.Client, kubeconfig
 			glog.Errorf("Failed to start the generic garbage collector")
 		} else {
 			// TODO: make this a flag of kube-controller-manager
-			workers := 5
+			workers := int(s.ConcurrentGCSyncs)
 			go garbageCollector.Run(workers, wait.NeverStop)
 		}
 	}

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

@@ -92,6 +92,7 @@ func NewCMServer() *CMServer {
 			LeaderElection:          leaderelection.DefaultLeaderElectionConfiguration(),
 			ControllerStartInterval: unversioned.Duration{Duration: 0 * time.Second},
 			EnableGarbageCollector:  false,
+			ConcurrentGCSyncs:       5,
 		},
 	}
 	return &s
@@ -163,5 +164,6 @@ func (s *CMServer) AddFlags(fs *pflag.FlagSet) {
 	fs.Int32Var(&s.KubeAPIBurst, "kube-api-burst", s.KubeAPIBurst, "Burst to use while talking with kubernetes apiserver")
 	fs.DurationVar(&s.ControllerStartInterval.Duration, "controller-start-interval", s.ControllerStartInterval.Duration, "Interval between starting controller managers.")
 	fs.BoolVar(&s.EnableGarbageCollector, "enable-garbage-collector", s.EnableGarbageCollector, "Enables the generic garbage collector. MUST be synced with the corresponding flag of the kube-apiserver. WARNING: the generic garbage collector is an alpha feature.")
+	fs.Int32Var(&s.ConcurrentGCSyncs, "concurrent-gc-syncs", s.ConcurrentGCSyncs, "The number of garbage collector workers that are allowed to sync concurrently.")
 	leaderelection.BindFlags(&s.LeaderElection, fs)
 }

hack/verify-flags/known-flags.txt

@@ -66,6 +66,7 @@ concurrent-replicaset-syncs
 concurrent-service-syncs
 concurrent-resource-quota-syncs
 concurrent-serviceaccount-token-syncs
+concurrent-gc-syncs
 config-sync-period
 configure-cbr0
 configure-cloud-routes

pkg/apis/componentconfig/types.go

@@ -570,6 +570,9 @@ type KubeControllerManagerConfiguration struct {
 	// corresponding flag of the kube-apiserver. WARNING: the generic garbage
 	// collector is an alpha feature.
 	EnableGarbageCollector bool `json:"enableGarbageCollector"`
+	// concurrentGCSyncs is the number of garbage collector workers that are
+	// allowed to sync concurrently.
+	ConcurrentGCSyncs int32 `json:"concurrentGCSyncs"`
 }
 
 // VolumeConfiguration contains *all* enumerated flags meant to configure all volume