let RC manager utilize the GC

pkg/controller/replication/replication_controller.go

@@ -26,6 +26,9 @@ import (
 
 	"github.com/golang/glog"
 	"k8s.io/kubernetes/pkg/api"
+	"k8s.io/kubernetes/pkg/api/errors"
+	"k8s.io/kubernetes/pkg/api/unversioned"
+	"k8s.io/kubernetes/pkg/api/v1"
 	"k8s.io/kubernetes/pkg/client/cache"
 	clientset "k8s.io/kubernetes/pkg/client/clientset_generated/internalclientset"
 	unversionedcore "k8s.io/kubernetes/pkg/client/clientset_generated/internalclientset/typed/core/unversioned"
@@ -36,6 +39,7 @@ import (
 	"k8s.io/kubernetes/pkg/labels"
 	"k8s.io/kubernetes/pkg/runtime"
 	"k8s.io/kubernetes/pkg/util"
+	utilerrors "k8s.io/kubernetes/pkg/util/errors"
 	"k8s.io/kubernetes/pkg/util/metrics"
 	utilruntime "k8s.io/kubernetes/pkg/util/runtime"
 	"k8s.io/kubernetes/pkg/util/wait"
@@ -65,6 +69,10 @@ const (
 	statusUpdateRetries = 1
 )
 
+func getRCKind() unversioned.GroupVersionKind {
+	return v1.SchemeGroupVersion.WithKind("ReplicationController")
+}
+
 // ReplicationManager is responsible for synchronizing ReplicationController objects stored
 // in the system with actual running pods.
 // TODO: this really should be called ReplicationController. The only reason why it's a Manager
@@ -105,20 +113,24 @@ type ReplicationManager struct {
 
 	// Controllers that need to be synced
 	queue *workqueue.Type
+
+	// garbageCollectorEnabled denotes if the garbage collector is enabled. RC
+	// manager behaves differently if GC is enabled.
+	garbageCollectorEnabled bool
 }
 
 // NewReplicationManager creates a replication manager
-func NewReplicationManager(podInformer framework.SharedIndexInformer, kubeClient clientset.Interface, resyncPeriod controller.ResyncPeriodFunc, burstReplicas int, lookupCacheSize int) *ReplicationManager {
+func NewReplicationManager(podInformer framework.SharedIndexInformer, kubeClient clientset.Interface, resyncPeriod controller.ResyncPeriodFunc, burstReplicas int, lookupCacheSize int, garbageCollectorEnabled bool) *ReplicationManager {
 	eventBroadcaster := record.NewBroadcaster()
 	eventBroadcaster.StartLogging(glog.Infof)
 	eventBroadcaster.StartRecordingToSink(&unversionedcore.EventSinkImpl{Interface: kubeClient.Core().Events("")})
-	return newReplicationManagerInternal(
+	return newReplicationManager(
 		eventBroadcaster.NewRecorder(api.EventSource{Component: "replication-controller"}),
-		podInformer, kubeClient, resyncPeriod, burstReplicas, lookupCacheSize)
+		podInformer, kubeClient, resyncPeriod, burstReplicas, lookupCacheSize, garbageCollectorEnabled)
 }
 
-// newReplicationManagerInternal configures a replication manager with the specified event recorder
-func newReplicationManagerInternal(eventRecorder record.EventRecorder, podInformer framework.SharedIndexInformer, kubeClient clientset.Interface, resyncPeriod controller.ResyncPeriodFunc, burstReplicas int, lookupCacheSize int) *ReplicationManager {
+// newReplicationManager configures a replication manager with the specified event recorder
+func newReplicationManager(eventRecorder record.EventRecorder, podInformer framework.SharedIndexInformer, kubeClient clientset.Interface, resyncPeriod controller.ResyncPeriodFunc, burstReplicas int, lookupCacheSize int, garbageCollectorEnabled bool) *ReplicationManager {
 	if kubeClient != nil && kubeClient.Core().GetRESTClient().GetRateLimiter() != nil {
 		metrics.RegisterMetricAndTrackRateLimiterUsage("replication_controller", kubeClient.Core().GetRESTClient().GetRateLimiter())
 	}
@@ -132,6 +144,7 @@ func newReplicationManagerInternal(eventRecorder record.EventRecorder, podInform
 		burstReplicas: burstReplicas,
 		expectations:  controller.NewUIDTrackingControllerExpectations(controller.NewControllerExpectations()),
 		queue:         workqueue.New(),
+		garbageCollectorEnabled: garbageCollectorEnabled,
 	}
 
 	rm.rcStore.Indexer, rm.rcController = framework.NewIndexerInformer(
@@ -147,43 +160,8 @@ func newReplicationManagerInternal(eventRecorder record.EventRecorder, podInform
 		// TODO: Can we have much longer period here?
 		FullControllerResyncPeriod,
 		framework.ResourceEventHandlerFuncs{
-			AddFunc: rm.enqueueController,
-			UpdateFunc: func(old, cur interface{}) {
-				oldRC := old.(*api.ReplicationController)
-				curRC := cur.(*api.ReplicationController)
-
-				// We should invalidate the whole lookup cache if a RC's selector has been updated.
-				//
-				// Imagine that you have two RCs:
-				// * old RC1
-				// * new RC2
-				// You also have a pod that is attached to RC2 (because it doesn't match RC1 selector).
-				// Now imagine that you are changing RC1 selector so that it is now matching that pod,
-				// in such case, we must invalidate the whole cache so that pod could be adopted by RC1
-				//
-				// This makes the lookup cache less helpful, but selector update does not happen often,
-				// so it's not a big problem
-				if !reflect.DeepEqual(oldRC.Spec.Selector, curRC.Spec.Selector) {
-					rm.lookupCache.InvalidateAll()
-				}
-
-				// You might imagine that we only really need to enqueue the
-				// controller when Spec changes, but it is safer to sync any
-				// time this function is triggered. That way a full informer
-				// resync can requeue any controllers that don't yet have pods
-				// but whose last attempts at creating a pod have failed (since
-				// we don't block on creation of pods) instead of those
-				// controllers stalling indefinitely. Enqueueing every time
-				// does result in some spurious syncs (like when Status.Replica
-				// is updated and the watch notification from it retriggers
-				// this function), but in general extra resyncs shouldn't be
-				// that bad as rcs that haven't met expectations yet won't
-				// sync, and all the listing is done using local stores.
-				if oldRC.Status.Replicas != curRC.Status.Replicas {
-					glog.V(4).Infof("Observed updated replica count for rc: %v, %d->%d", curRC.Name, oldRC.Status.Replicas, curRC.Status.Replicas)
-				}
-				rm.enqueueController(cur)
-			},
+			AddFunc:    rm.enqueueController,
+			UpdateFunc: rm.updateRC,
 			// This will enter the sync loop and no-op, because the controller has been deleted from the store.
 			// Note that deleting a controller immediately after scaling it to 0 will not work. The recommended
 			// way of achieving this is by performing a `stop` operation on the controller.
@@ -212,7 +190,8 @@ func newReplicationManagerInternal(eventRecorder record.EventRecorder, podInform
 // NewReplicationManagerFromClientForIntegration creates a new ReplicationManager that runs its own informer.  It disables event recording for use in integration tests.
 func NewReplicationManagerFromClientForIntegration(kubeClient clientset.Interface, resyncPeriod controller.ResyncPeriodFunc, burstReplicas int, lookupCacheSize int) *ReplicationManager {
 	podInformer := informers.CreateSharedPodIndexInformer(kubeClient, resyncPeriod())
-	rm := newReplicationManagerInternal(&record.FakeRecorder{}, podInformer, kubeClient, resyncPeriod, burstReplicas, lookupCacheSize)
+	garbageCollectorEnabled := false
+	rm := newReplicationManager(&record.FakeRecorder{}, podInformer, kubeClient, resyncPeriod, burstReplicas, lookupCacheSize, garbageCollectorEnabled)
 	rm.internalPodInformer = podInformer
 	return rm
 }
@@ -220,7 +199,8 @@ func NewReplicationManagerFromClientForIntegration(kubeClient clientset.Interfac
 // NewReplicationManagerFromClient creates a new ReplicationManager that runs its own informer.
 func NewReplicationManagerFromClient(kubeClient clientset.Interface, resyncPeriod controller.ResyncPeriodFunc, burstReplicas int, lookupCacheSize int) *ReplicationManager {
 	podInformer := informers.CreateSharedPodIndexInformer(kubeClient, resyncPeriod())
-	rm := NewReplicationManager(podInformer, kubeClient, resyncPeriod, burstReplicas, lookupCacheSize)
+	garbageCollectorEnabled := false
+	rm := NewReplicationManager(podInformer, kubeClient, resyncPeriod, burstReplicas, lookupCacheSize, garbageCollectorEnabled)
 	rm.internalPodInformer = podInformer
 
 	return rm
@@ -255,13 +235,14 @@ func (rm *ReplicationManager) Run(workers int, stopCh <-chan struct{}) {
 
 // getPodController returns the controller managing the given pod.
 // TODO: Surface that we are ignoring multiple controllers for a single pod.
+// TODO: use ownerReference.Controller to determine if the rc controls the pod.
 func (rm *ReplicationManager) getPodController(pod *api.Pod) *api.ReplicationController {
 	// look up in the cache, if cached and the cache is valid, just return cached value
 	if obj, cached := rm.lookupCache.GetMatchingObject(pod); cached {
 		controller, ok := obj.(*api.ReplicationController)
 		if !ok {
 			// This should not happen
-			glog.Errorf("lookup cache does not retuen a ReplicationController object")
+			glog.Errorf("lookup cache does not return a ReplicationController object")
 			return nil
 		}
 		if cached && rm.isCacheValid(pod, controller) {
@@ -320,6 +301,44 @@ func isControllerMatch(pod *api.Pod, rc *api.ReplicationController) bool {
 	return true
 }
 
+// callback when RC is updated
+func (rm *ReplicationManager) updateRC(old, cur interface{}) {
+	oldRC := old.(*api.ReplicationController)
+	curRC := cur.(*api.ReplicationController)
+
+	// We should invalidate the whole lookup cache if a RC's selector has been updated.
+	//
+	// Imagine that you have two RCs:
+	// * old RC1
+	// * new RC2
+	// You also have a pod that is attached to RC2 (because it doesn't match RC1 selector).
+	// Now imagine that you are changing RC1 selector so that it is now matching that pod,
+	// in such case, we must invalidate the whole cache so that pod could be adopted by RC1
+	//
+	// This makes the lookup cache less helpful, but selector update does not happen often,
+	// so it's not a big problem
+	if !reflect.DeepEqual(oldRC.Spec.Selector, curRC.Spec.Selector) {
+		rm.lookupCache.InvalidateAll()
+	}
+
+	// You might imagine that we only really need to enqueue the
+	// controller when Spec changes, but it is safer to sync any
+	// time this function is triggered. That way a full informer
+	// resync can requeue any controllers that don't yet have pods
+	// but whose last attempts at creating a pod have failed (since
+	// we don't block on creation of pods) instead of those
+	// controllers stalling indefinitely. Enqueueing every time
+	// does result in some spurious syncs (like when Status.Replica
+	// is updated and the watch notification from it retriggers
+	// this function), but in general extra resyncs shouldn't be
+	// that bad as rcs that haven't met expectations yet won't
+	// sync, and all the listing is done using local stores.
+	if oldRC.Status.Replicas != curRC.Status.Replicas {
+		glog.V(4).Infof("Observed updated replica count for rc: %v, %d->%d", curRC.Name, oldRC.Status.Replicas, curRC.Status.Replicas)
+	}
+	rm.enqueueController(cur)
+}
+
 // When a pod is created, enqueue the controller that manages it and update it's expectations.
 func (rm *ReplicationManager) addPod(obj interface{}) {
 	pod := obj.(*api.Pod)
@@ -370,10 +389,8 @@ func (rm *ReplicationManager) updatePod(old, cur interface{}) {
 		return
 	}
 
-	if rc := rm.getPodController(curPod); rc != nil {
-		rm.enqueueController(rc)
-	}
 	// Only need to get the old controller if the labels changed.
+	// Enqueue the oldRC before the curRC to give curRC a chance to adopt the oldPod.
 	if labelChanged {
 		// If the old and new rc are the same, the first one that syncs
 		// will set expectations preventing any damage from the second.
@@ -381,6 +398,10 @@ func (rm *ReplicationManager) updatePod(old, cur interface{}) {
 			rm.enqueueController(oldRC)
 		}
 	}
+
+	if curRC := rm.getPodController(curPod); curRC != nil {
+		rm.enqueueController(curRC)
+	}
 }
 
 // When a pod is deleted, enqueue the controller that manages the pod and update its expectations.
@@ -481,7 +502,21 @@ func (rm *ReplicationManager) manageReplicas(filteredPods []*api.Pod, rc *api.Re
 		for i := 0; i < diff; i++ {
 			go func() {
 				defer wg.Done()
-				if err := rm.podControl.CreatePods(rc.Namespace, rc.Spec.Template, rc); err != nil {
+				var err error
+				if rm.garbageCollectorEnabled {
+					var trueVar = true
+					controllerRef := &api.OwnerReference{
+						APIVersion: getRCKind().GroupVersion().String(),
+						Kind:       getRCKind().Kind,
+						Name:       rc.Name,
+						UID:        rc.UID,
+						Controller: &trueVar,
+					}
+					err = rm.podControl.CreatePodsWithControllerRef(rc.Namespace, rc.Spec.Template, rc, controllerRef)
+				} else {
+					err = rm.podControl.CreatePods(rc.Namespace, rc.Spec.Template, rc)
+				}
+				if err != nil {
 					// Decrement the expected number of creates because the informer won't observe this pod
 					glog.V(2).Infof("Failed creation, decrementing expectations for controller %q/%q", rc.Namespace, rc.Name)
 					rm.expectations.CreationObserved(rcKey)
@@ -580,7 +615,6 @@ func (rm *ReplicationManager) syncReplicationController(key string) error {
 	trace.Step("ReplicationController restored")
 	rcNeedsSync := rm.expectations.SatisfiedExpectations(rcKey)
 	trace.Step("Expectations restored")
-	podList, err := rm.podStore.Pods(rc.Namespace).List(labels.Set(rc.Spec.Selector).AsSelector())
 	if err != nil {
 		glog.Errorf("Error getting pods for rc %q: %v", key, err)
 		rm.queue.Add(key)
@@ -588,9 +622,59 @@ func (rm *ReplicationManager) syncReplicationController(key string) error {
 	}
 	trace.Step("Pods listed")
 
-	// TODO: Do this in a single pass, or use an index.
-	filteredPods := controller.FilterActivePods(podList.Items)
-	if rcNeedsSync {
+	// TODO: Do the List and Filter in a single pass, or use an index.
+	var filteredPods []*api.Pod
+	if rm.garbageCollectorEnabled {
+		// list all pods to include the pods that don't match the rc's selector
+		// anymore but has the stale controller ref.
+		podList, err := rm.podStore.Pods(rc.Namespace).List(labels.Everything())
+		if err != nil {
+			glog.Errorf("Error getting pods for rc %q: %v", key, err)
+			rm.queue.Add(key)
+			return err
+		}
+		cm := controller.NewPodControllerRefManager(rm.podControl, rc.ObjectMeta, labels.Set(rc.Spec.Selector).AsSelector(), getRCKind())
+		matchesAndControlled, matchesNeedsController, controlledDoesNotMatch := cm.Classify(podList.Items)
+		for _, pod := range matchesNeedsController {
+			err := cm.AdoptPod(pod)
+			// continue to next pod if adoption fails.
+			if err != nil {
+				// If the pod no longer exists, don't even log the error.
+				if !errors.IsNotFound(err) {
+					utilruntime.HandleError(err)
+				}
+			} else {
+				matchesAndControlled = append(matchesAndControlled, pod)
+			}
+		}
+		filteredPods = matchesAndControlled
+		// remove the controllerRef for the pods that no longer have matching labels
+		var errlist []error
+		for _, pod := range controlledDoesNotMatch {
+			err := cm.ReleasePod(pod)
+			if err != nil {
+				errlist = append(errlist, cm.ReleasePod(pod))
+			}
+		}
+		if len(errlist) != 0 {
+			aggregate := utilerrors.NewAggregate(errlist)
+			// push the RC into work queue again. We need to try to free the
+			// pods again otherwise they will stuck with the stale
+			// controllerRef.
+			rm.queue.Add(key)
+			return aggregate
+		}
+	} else {
+		podList, err := rm.podStore.Pods(rc.Namespace).List(labels.Set(rc.Spec.Selector).AsSelector())
+		if err != nil {
+			glog.Errorf("Error getting pods for rc %q: %v", key, err)
+			rm.queue.Add(key)
+			return err
+		}
+		filteredPods = controller.FilterActivePods(podList.Items)
+	}
+
+	if rcNeedsSync && rc.DeletionTimestamp == nil {
 		rm.manageReplicas(filteredPods, &rc)
 	}
 	trace.Step("manageReplicas done")

pkg/controller/replication/replication_controller_test.go

@@ -95,34 +95,45 @@ func newReplicationController(replicas int) *api.ReplicationController {
 	return rc
 }
 
+// create a pod with the given phase for the given rc (same selectors and namespace).
+func newPod(name string, rc *api.ReplicationController, status api.PodPhase) *api.Pod {
+	return &api.Pod{
+		ObjectMeta: api.ObjectMeta{
+			Name:      name,
+			Labels:    rc.Spec.Selector,
+			Namespace: rc.Namespace,
+		},
+		Status: api.PodStatus{Phase: status},
+	}
+}
+
 // create count pods with the given phase for the given rc (same selectors and namespace), and add them to the store.
 func newPodList(store cache.Store, count int, status api.PodPhase, rc *api.ReplicationController, name string) *api.PodList {
 	pods := []api.Pod{}
+	var trueVar = true
+	controllerReference := api.OwnerReference{UID: rc.UID, APIVersion: "v1", Kind: "ReplicationController", Name: rc.Name, Controller: &trueVar}
 	for i := 0; i < count; i++ {
-		newPod := api.Pod{
-			ObjectMeta: api.ObjectMeta{
-				Name:      fmt.Sprintf("%s%d", name, i),
-				Labels:    rc.Spec.Selector,
-				Namespace: rc.Namespace,
-			},
-			Status: api.PodStatus{Phase: status},
-		}
+		pod := newPod(fmt.Sprintf("%s%d", name, i), rc, status)
+		pod.OwnerReferences = []api.OwnerReference{controllerReference}
 		if store != nil {
-			store.Add(&newPod)
+			store.Add(pod)
 		}
-		pods = append(pods, newPod)
+		pods = append(pods, *pod)
 	}
 	return &api.PodList{
 		Items: pods,
 	}
 }
 
-func validateSyncReplication(t *testing.T, fakePodControl *controller.FakePodControl, expectedCreates, expectedDeletes int) {
-	if len(fakePodControl.Templates) != expectedCreates {
-		t.Errorf("Unexpected number of creates.  Expected %d, saw %d\n", expectedCreates, len(fakePodControl.Templates))
+func validateSyncReplication(t *testing.T, fakePodControl *controller.FakePodControl, expectedCreates, expectedDeletes, expectedPatches int) {
+	if e, a := expectedCreates, len(fakePodControl.Templates); e != a {
+		t.Errorf("Unexpected number of creates.  Expected %d, saw %d\n", e, a)
 	}
-	if len(fakePodControl.DeletePodName) != expectedDeletes {
-		t.Errorf("Unexpected number of deletes.  Expected %d, saw %d\n", expectedDeletes, len(fakePodControl.DeletePodName))
+	if e, a := expectedDeletes, len(fakePodControl.DeletePodName); e != a {
+		t.Errorf("Unexpected number of deletes.  Expected %d, saw %d\n", e, a)
+	}
+	if e, a := expectedPatches, len(fakePodControl.Patches); e != a {
+		t.Errorf("Unexpected number of patches.  Expected %d, saw %d\n", e, a)
 	}
 }
 
@@ -148,7 +159,7 @@ func TestSyncReplicationControllerDoesNothing(t *testing.T) {
 
 	manager.podControl = &fakePodControl
 	manager.syncReplicationController(getKey(controllerSpec, t))
-	validateSyncReplication(t, &fakePodControl, 0, 0)
+	validateSyncReplication(t, &fakePodControl, 0, 0, 0)
 }
 
 func TestSyncReplicationControllerDeletes(t *testing.T) {
@@ -164,7 +175,7 @@ func TestSyncReplicationControllerDeletes(t *testing.T) {
 	newPodList(manager.podStore.Indexer, 2, api.PodRunning, controllerSpec, "pod")
 
 	manager.syncReplicationController(getKey(controllerSpec, t))
-	validateSyncReplication(t, &fakePodControl, 0, 1)
+	validateSyncReplication(t, &fakePodControl, 0, 1, 0)
 }
 
 func TestDeleteFinalStateUnknown(t *testing.T) {
@@ -212,7 +223,7 @@ func TestSyncReplicationControllerCreates(t *testing.T) {
 	fakePodControl := controller.FakePodControl{}
 	manager.podControl = &fakePodControl
 	manager.syncReplicationController(getKey(rc, t))
-	validateSyncReplication(t, &fakePodControl, 2, 0)
+	validateSyncReplication(t, &fakePodControl, 2, 0, 0)
 }
 
 func TestStatusUpdatesWithoutReplicasChange(t *testing.T) {
@@ -238,7 +249,7 @@ func TestStatusUpdatesWithoutReplicasChange(t *testing.T) {
 	manager.podControl = &fakePodControl
 	manager.syncReplicationController(getKey(rc, t))
 
-	validateSyncReplication(t, &fakePodControl, 0, 0)
+	validateSyncReplication(t, &fakePodControl, 0, 0, 0)
 	if fakeHandler.RequestReceived != nil {
 		t.Errorf("Unexpected update when pods and rcs are in a steady state")
 	}
@@ -297,7 +308,7 @@ func TestControllerUpdateReplicas(t *testing.T) {
 
 	decRc := runtime.EncodeOrDie(testapi.Default.Codec(), rc)
 	fakeHandler.ValidateRequest(t, testapi.Default.ResourcePath(replicationControllerResourceName(), rc.Namespace, rc.Name)+"/status", "PUT", &decRc)
-	validateSyncReplication(t, &fakePodControl, 1, 0)
+	validateSyncReplication(t, &fakePodControl, 1, 0, 0)
 }
 
 func TestSyncReplicationControllerDormancy(t *testing.T) {
@@ -321,13 +332,13 @@ func TestSyncReplicationControllerDormancy(t *testing.T) {
 	// Creates a replica and sets expectations
 	controllerSpec.Status.Replicas = 1
 	manager.syncReplicationController(getKey(controllerSpec, t))
-	validateSyncReplication(t, &fakePodControl, 1, 0)
+	validateSyncReplication(t, &fakePodControl, 1, 0, 0)
 
 	// Expectations prevents replicas but not an update on status
 	controllerSpec.Status.Replicas = 0
 	fakePodControl.Clear()
 	manager.syncReplicationController(getKey(controllerSpec, t))
-	validateSyncReplication(t, &fakePodControl, 0, 0)
+	validateSyncReplication(t, &fakePodControl, 0, 0, 0)
 
 	// Get the key for the controller
 	rcKey, err := controller.KeyFunc(controllerSpec)
@@ -336,19 +347,20 @@ func TestSyncReplicationControllerDormancy(t *testing.T) {
 	}
 
 	// Lowering expectations should lead to a sync that creates a replica, however the
-	// fakePodControl error will prevent this, leaving expectations at 0, 0
+	// fakePodControl error will prevent this, leaving expectations at 0, 0.
 	manager.expectations.CreationObserved(rcKey)
 	controllerSpec.Status.Replicas = 1
 	fakePodControl.Clear()
 	fakePodControl.Err = fmt.Errorf("Fake Error")
 
 	manager.syncReplicationController(getKey(controllerSpec, t))
-	validateSyncReplication(t, &fakePodControl, 0, 0)
+	validateSyncReplication(t, &fakePodControl, 1, 0, 0)
 
 	// This replica should not need a Lowering of expectations, since the previous create failed
+	fakePodControl.Clear()
 	fakePodControl.Err = nil
 	manager.syncReplicationController(getKey(controllerSpec, t))
-	validateSyncReplication(t, &fakePodControl, 1, 0)
+	validateSyncReplication(t, &fakePodControl, 1, 0, 0)
 
 	// 1 PUT for the rc status during dormancy window.
 	// Note that the pod creates go through pod control so they're not recorded.
@@ -697,7 +709,7 @@ func doTestControllerBurstReplicas(t *testing.T, burstReplicas, numReplicas int)
 					expectedPods = burstReplicas
 				}
 				// This validates the rc manager sync actually created pods
-				validateSyncReplication(t, &fakePodControl, expectedPods, 0)
+				validateSyncReplication(t, &fakePodControl, expectedPods, 0, 0)
 
 				// This simulates the watch events for all but 1 of the expected pods.
 				// None of these should wake the controller because it has expectations==BurstReplicas.
@@ -718,7 +730,7 @@ func doTestControllerBurstReplicas(t *testing.T, burstReplicas, numReplicas int)
 				if expectedPods > burstReplicas {
 					expectedPods = burstReplicas
 				}
-				validateSyncReplication(t, &fakePodControl, 0, expectedPods)
+				validateSyncReplication(t, &fakePodControl, 0, expectedPods, 0)
 
 				// To accurately simulate a watch we must delete the exact pods
 				// the rc is waiting for.
@@ -753,7 +765,7 @@ func doTestControllerBurstReplicas(t *testing.T, burstReplicas, numReplicas int)
 			// Check that the rc didn't take any action for all the above pods
 			fakePodControl.Clear()
 			manager.syncReplicationController(getKey(controllerSpec, t))
-			validateSyncReplication(t, &fakePodControl, 0, 0)
+			validateSyncReplication(t, &fakePodControl, 0, 0, 0)
 
 			// Create/Delete the last pod
 			// The last add pod will decrease the expectation of the rc to 0,
@@ -831,7 +843,7 @@ func TestRCSyncExpectations(t *testing.T) {
 		},
 	})
 	manager.syncReplicationController(getKey(controllerSpec, t))
-	validateSyncReplication(t, &fakePodControl, 0, 0)
+	validateSyncReplication(t, &fakePodControl, 0, 0, 0)
 }
 
 func TestDeleteControllerAndExpectations(t *testing.T) {
@@ -847,7 +859,7 @@ func TestDeleteControllerAndExpectations(t *testing.T) {
 
 	// This should set expectations for the rc
 	manager.syncReplicationController(getKey(rc, t))
-	validateSyncReplication(t, &fakePodControl, 1, 0)
+	validateSyncReplication(t, &fakePodControl, 1, 0, 0)
 	fakePodControl.Clear()
 
 	// Get the RC key
@@ -873,7 +885,7 @@ func TestDeleteControllerAndExpectations(t *testing.T) {
 	podExp.Add(-1, 0)
 	manager.podStore.Indexer.Replace(make([]interface{}, 0), "0")
 	manager.syncReplicationController(getKey(rc, t))
-	validateSyncReplication(t, &fakePodControl, 0, 0)
+	validateSyncReplication(t, &fakePodControl, 0, 0, 0)
 }
 
 func TestRCManagerNotReady(t *testing.T) {
@@ -891,7 +903,7 @@ func TestRCManagerNotReady(t *testing.T) {
 
 	rcKey := getKey(controllerSpec, t)
 	manager.syncReplicationController(rcKey)
-	validateSyncReplication(t, &fakePodControl, 0, 0)
+	validateSyncReplication(t, &fakePodControl, 0, 0, 0)
 	queueRC, _ := manager.queue.Get()
 	if queueRC != rcKey {
 		t.Fatalf("Expected to find key %v in queue, found %v", rcKey, queueRC)
@@ -899,7 +911,7 @@ func TestRCManagerNotReady(t *testing.T) {
 
 	manager.podStoreSynced = alwaysReady
 	manager.syncReplicationController(rcKey)
-	validateSyncReplication(t, &fakePodControl, 1, 0)
+	validateSyncReplication(t, &fakePodControl, 1, 0, 0)
 }
 
 // shuffle returns a new shuffled list of container controllers.
@@ -1116,3 +1128,193 @@ func BenchmarkGetPodControllerSingleNS(b *testing.B) {
 		}
 	}
 }
+
+// setupManagerWithGCEnabled creates a RC manager with a fakePodControl and with garbageCollectorEnabled set to true
+func setupManagerWithGCEnabled() (manager *ReplicationManager, fakePodControl *controller.FakePodControl) {
+	c := clientset.NewForConfigOrDie(&restclient.Config{Host: "", ContentConfig: restclient.ContentConfig{GroupVersion: testapi.Default.GroupVersion()}})
+	fakePodControl = &controller.FakePodControl{}
+	manager = NewReplicationManagerFromClient(c, controller.NoResyncPeriodFunc, BurstReplicas, 0)
+	manager.garbageCollectorEnabled = true
+	manager.podStoreSynced = alwaysReady
+	manager.podControl = fakePodControl
+	return manager, fakePodControl
+}
+
+func TestDoNotPatchPodWithOtherControlRef(t *testing.T) {
+	manager, fakePodControl := setupManagerWithGCEnabled()
+	rc := newReplicationController(2)
+	manager.rcStore.Indexer.Add(rc)
+	var trueVar = true
+	otherControllerReference := api.OwnerReference{UID: util.NewUUID(), APIVersion: "v1", Kind: "ReplicationController", Name: "AnotherRC", Controller: &trueVar}
+	// add to podStore a matching Pod controlled by another controller. Expect no patch.
+	pod := newPod("pod", rc, api.PodRunning)
+	pod.OwnerReferences = []api.OwnerReference{otherControllerReference}
+	manager.podStore.Indexer.Add(pod)
+	err := manager.syncReplicationController(getKey(rc, t))
+	if err != nil {
+		t.Fatal(err)
+	}
+	// because the matching pod already has a controller, so 2 pods should be created.
+	validateSyncReplication(t, fakePodControl, 2, 0, 0)
+}
+
+func TestPatchPodWithOtherOwnerRef(t *testing.T) {
+	manager, fakePodControl := setupManagerWithGCEnabled()
+	rc := newReplicationController(2)
+	manager.rcStore.Indexer.Add(rc)
+	// add to podStore one more matching pod that doesn't have a controller
+	// ref, but has an owner ref pointing to other object. Expect a patch to
+	// take control of it.
+	unrelatedOwnerReference := api.OwnerReference{UID: util.NewUUID(), APIVersion: "batch/v1", Kind: "Job", Name: "Job"}
+	pod := newPod("pod", rc, api.PodRunning)
+	pod.OwnerReferences = []api.OwnerReference{unrelatedOwnerReference}
+	manager.podStore.Indexer.Add(pod)
+
+	err := manager.syncReplicationController(getKey(rc, t))
+	if err != nil {
+		t.Fatal(err)
+	}
+	// 1 patch to take control of pod, and 1 create of new pod.
+	validateSyncReplication(t, fakePodControl, 1, 0, 1)
+}
+
+func TestPatchPodWithCorrectOwnerRef(t *testing.T) {
+	manager, fakePodControl := setupManagerWithGCEnabled()
+	rc := newReplicationController(2)
+	manager.rcStore.Indexer.Add(rc)
+	// add to podStore a matching pod that has an ownerRef pointing to the rc,
+	// but ownerRef.Controller is false. Expect a patch to take control it.
+	rcOwnerReference := api.OwnerReference{UID: rc.UID, APIVersion: "v1", Kind: "ReplicationController", Name: rc.Name}
+	pod := newPod("pod", rc, api.PodRunning)
+	pod.OwnerReferences = []api.OwnerReference{rcOwnerReference}
+	manager.podStore.Indexer.Add(pod)
+
+	err := manager.syncReplicationController(getKey(rc, t))
+	if err != nil {
+		t.Fatal(err)
+	}
+	// 1 patch to take control of pod, and 1 create of new pod.
+	validateSyncReplication(t, fakePodControl, 1, 0, 1)
+}
+
+func TestPatchPodFails(t *testing.T) {
+	manager, fakePodControl := setupManagerWithGCEnabled()
+	rc := newReplicationController(2)
+	manager.rcStore.Indexer.Add(rc)
+	// add to podStore two matching pods. Expect two patches to take control
+	// them.
+	manager.podStore.Indexer.Add(newPod("pod1", rc, api.PodRunning))
+	manager.podStore.Indexer.Add(newPod("pod2", rc, api.PodRunning))
+	// let both patches fail. The rc manager will assume it fails to take
+	// control of the pods and create new ones.
+	fakePodControl.Err = fmt.Errorf("Fake Error")
+	err := manager.syncReplicationController(getKey(rc, t))
+	if err != nil {
+		t.Fatal(err)
+	}
+	// 2 patches to take control of pod1 and pod2 (both fail), 2 creates.
+	validateSyncReplication(t, fakePodControl, 2, 0, 2)
+}
+
+func TestPatchExtraPodsThenDelete(t *testing.T) {
+	manager, fakePodControl := setupManagerWithGCEnabled()
+	rc := newReplicationController(2)
+	manager.rcStore.Indexer.Add(rc)
+	// add to podStore three matching pods. Expect three patches to take control
+	// them, and later delete one of them.
+	manager.podStore.Indexer.Add(newPod("pod1", rc, api.PodRunning))
+	manager.podStore.Indexer.Add(newPod("pod2", rc, api.PodRunning))
+	manager.podStore.Indexer.Add(newPod("pod3", rc, api.PodRunning))
+	err := manager.syncReplicationController(getKey(rc, t))
+	if err != nil {
+		t.Fatal(err)
+	}
+	// 3 patches to take control of the pods, and 1 deletion because there is an extra pod.
+	validateSyncReplication(t, fakePodControl, 0, 1, 3)
+}
+
+func TestUpdateLabelsRemoveControllerRef(t *testing.T) {
+	manager, fakePodControl := setupManagerWithGCEnabled()
+	rc := newReplicationController(2)
+	manager.rcStore.Indexer.Add(rc)
+	// put one pod in the podStore
+	pod := newPod("pod", rc, api.PodRunning)
+	var trueVar = true
+	rcOwnerReference := api.OwnerReference{UID: rc.UID, APIVersion: "v1", Kind: "ReplicationController", Name: rc.Name, Controller: &trueVar}
+	pod.OwnerReferences = []api.OwnerReference{rcOwnerReference}
+	updatedPod := *pod
+	// reset the labels
+	updatedPod.Labels = make(map[string]string)
+	// add the updatedPod to the store. This is consistent with the behavior of
+	// the Informer: Informer updates the store before call the handler
+	// (updatePod() in this case).
+	manager.podStore.Indexer.Add(&updatedPod)
+	// send a update of the same pod with modified labels
+	manager.updatePod(pod, &updatedPod)
+	// verifies that rc is added to the queue
+	rcKey := getKey(rc, t)
+	queueRC, _ := manager.queue.Get()
+	if queueRC != rcKey {
+		t.Fatalf("Expected to find key %v in queue, found %v", rcKey, queueRC)
+	}
+	manager.queue.Done(queueRC)
+	err := manager.syncReplicationController(rcKey)
+	if err != nil {
+		t.Fatal(err)
+	}
+	// expect 1 patch to be sent to remove the controllerRef for the pod.
+	// expect 2 creates because the rc.Spec.Replicas=2 and there exists no
+	// matching pod.
+	validateSyncReplication(t, fakePodControl, 2, 0, 1)
+	fakePodControl.Clear()
+}
+
+func TestUpdateSelectorControllerRef(t *testing.T) {
+	manager, fakePodControl := setupManagerWithGCEnabled()
+	rc := newReplicationController(2)
+	// put 2 pods in the podStore
+	newPodList(manager.podStore.Indexer, 2, api.PodRunning, rc, "pod")
+	// update the RC so that its selector no longer matches the pods
+	updatedRC := *rc
+	updatedRC.Spec.Selector = map[string]string{"foo": "baz"}
+	// put the updatedRC into the store. This is consistent with the behavior of
+	// the Informer: Informer updates the store before call the handler
+	// (updateRC() in this case).
+	manager.rcStore.Indexer.Add(&updatedRC)
+	manager.updateRC(rc, &updatedRC)
+	// verifies that the rc is added to the queue
+	rcKey := getKey(rc, t)
+	queueRC, _ := manager.queue.Get()
+	if queueRC != rcKey {
+		t.Fatalf("Expected to find key %v in queue, found %v", rcKey, queueRC)
+	}
+	manager.queue.Done(queueRC)
+	err := manager.syncReplicationController(rcKey)
+	if err != nil {
+		t.Fatal(err)
+	}
+	// expect 2 patches to be sent to remove the controllerRef for the pods.
+	// expect 2 creates because the rc.Spec.Replicas=2 and there exists no
+	// matching pod.
+	validateSyncReplication(t, fakePodControl, 2, 0, 2)
+	fakePodControl.Clear()
+}
+
+// RC manager shouldn't adopt or create more pods if the rc is about to be
+// deleted.
+func TestDoNotAdoptOrCreateIfBeingDeleted(t *testing.T) {
+	manager, fakePodControl := setupManagerWithGCEnabled()
+	rc := newReplicationController(2)
+	now := unversioned.Now()
+	rc.DeletionTimestamp = &now
+	manager.rcStore.Indexer.Add(rc)
+	pod1 := newPod("pod1", rc, api.PodRunning)
+	manager.podStore.Indexer.Add(pod1)
+
+	// no patch, no create
+	err := manager.syncReplicationController(getKey(rc, t))
+	if err != nil {
+		t.Fatal(err)
+	}
+	validateSyncReplication(t, fakePodControl, 0, 0, 0)
+}