Implement replica set controller.

pkg/controller/replicaset/doc.go

@@ -0,0 +1,19 @@
+/*
+Copyright 2016 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Package replicaset contains logic for watching and synchronizing
+// ReplicaSets.
+package replicaset

pkg/controller/replicaset/replica_set.go

@@ -0,0 +1,463 @@
+/*
+Copyright 2016 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// If you make changes to this file, you should also make the corresponding change in ReplicationController.
+
+package replicaset
+
+import (
+	"reflect"
+	"sort"
+	"sync"
+	"time"
+
+	"github.com/golang/glog"
+	"k8s.io/kubernetes/pkg/api"
+	"k8s.io/kubernetes/pkg/apis/extensions"
+	"k8s.io/kubernetes/pkg/client/cache"
+	"k8s.io/kubernetes/pkg/client/record"
+	client "k8s.io/kubernetes/pkg/client/unversioned"
+	"k8s.io/kubernetes/pkg/controller"
+	"k8s.io/kubernetes/pkg/controller/framework"
+	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/util"
+	"k8s.io/kubernetes/pkg/util/workqueue"
+	"k8s.io/kubernetes/pkg/watch"
+)
+
+const (
+	// We'll attempt to recompute the required replicas of all ReplicaSets
+	// that have fulfilled their expectations at least this often. This recomputation
+	// happens based on contents in local pod storage.
+	FullControllerResyncPeriod = 30 * time.Second
+
+	// Realistic value of the burstReplica field for the replication manager based off
+	// performance requirements for kubernetes 1.0.
+	BurstReplicas = 500
+
+	// We must avoid counting pods until the pod store has synced. If it hasn't synced, to
+	// avoid a hot loop, we'll wait this long between checks.
+	PodStoreSyncedPollPeriod = 100 * time.Millisecond
+
+	// The number of times we retry updating a ReplicaSet's status.
+	statusUpdateRetries = 1
+)
+
+// ReplicaSetController is responsible for synchronizing ReplicaSet objects stored
+// in the system with actual running pods.
+type ReplicaSetController struct {
+	kubeClient client.Interface
+	podControl controller.PodControlInterface
+
+	// A ReplicaSet is temporarily suspended after creating/deleting these many replicas.
+	// It resumes normal action after observing the watch events for them.
+	burstReplicas int
+	// To allow injection of syncReplicaSet for testing.
+	syncHandler func(rsKey string) error
+
+	// A TTLCache of pod creates/deletes each ReplicaSet expects to see
+	expectations controller.ControllerExpectationsInterface
+
+	// A store of ReplicaSets, populated by the rsController
+	rsStore cache.StoreToReplicaSetLister
+	// Watches changes to all ReplicaSets
+	rsController *framework.Controller
+	// A store of pods, populated by the podController
+	podStore cache.StoreToPodLister
+	// Watches changes to all pods
+	podController *framework.Controller
+	// podStoreSynced returns true if the pod store has been synced at least once.
+	// Added as a member to the struct to allow injection for testing.
+	podStoreSynced func() bool
+
+	// Controllers that need to be synced
+	queue *workqueue.Type
+}
+
+// NewReplicaSetController creates a new ReplicaSetController.
+func NewReplicaSetController(kubeClient client.Interface, resyncPeriod controller.ResyncPeriodFunc, burstReplicas int) *ReplicaSetController {
+	eventBroadcaster := record.NewBroadcaster()
+	eventBroadcaster.StartLogging(glog.Infof)
+	eventBroadcaster.StartRecordingToSink(kubeClient.Events(""))
+
+	rsc := &ReplicaSetController{
+		kubeClient: kubeClient,
+		podControl: controller.RealPodControl{
+			KubeClient: kubeClient,
+			Recorder:   eventBroadcaster.NewRecorder(api.EventSource{Component: "replicaset-controller"}),
+		},
+		burstReplicas: burstReplicas,
+		expectations:  controller.NewControllerExpectations(),
+		queue:         workqueue.New(),
+	}
+
+	rsc.rsStore.Store, rsc.rsController = framework.NewInformer(
+		&cache.ListWatch{
+			ListFunc: func(options api.ListOptions) (runtime.Object, error) {
+				return rsc.kubeClient.Extensions().ReplicaSets(api.NamespaceAll).List(options)
+			},
+			WatchFunc: func(options api.ListOptions) (watch.Interface, error) {
+				return rsc.kubeClient.Extensions().ReplicaSets(api.NamespaceAll).Watch(options)
+			},
+		},
+		&extensions.ReplicaSet{},
+		// TODO: Can we have much longer period here?
+		FullControllerResyncPeriod,
+		framework.ResourceEventHandlerFuncs{
+			AddFunc: rsc.enqueueReplicaSet,
+			UpdateFunc: func(old, cur interface{}) {
+				// You might imagine that we only really need to enqueue the
+				// replica set when Spec changes, but it is safer to sync any
+				// time this function is triggered. That way a full informer
+				// resync can requeue any replica set 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
+				// replica sets 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 ReplicaSets that haven't met expectations yet won't
+				// sync, and all the listing is done using local stores.
+				oldRS := old.(*extensions.ReplicaSet)
+				curRS := cur.(*extensions.ReplicaSet)
+				if oldRS.Status.Replicas != curRS.Status.Replicas {
+					glog.V(4).Infof("Observed updated replica count for ReplicaSet: %v, %d->%d", curRS.Name, oldRS.Status.Replicas, curRS.Status.Replicas)
+				}
+				rsc.enqueueReplicaSet(cur)
+			},
+			// This will enter the sync loop and no-op, because the replica set has been deleted from the store.
+			// Note that deleting a replica set immediately after scaling it to 0 will not work. The recommended
+			// way of achieving this is by performing a `stop` operation on the replica set.
+			DeleteFunc: rsc.enqueueReplicaSet,
+		},
+	)
+
+	rsc.podStore.Store, rsc.podController = framework.NewInformer(
+		&cache.ListWatch{
+			ListFunc: func(options api.ListOptions) (runtime.Object, error) {
+				return rsc.kubeClient.Pods(api.NamespaceAll).List(options)
+			},
+			WatchFunc: func(options api.ListOptions) (watch.Interface, error) {
+				return rsc.kubeClient.Pods(api.NamespaceAll).Watch(options)
+			},
+		},
+		&api.Pod{},
+		resyncPeriod(),
+		framework.ResourceEventHandlerFuncs{
+			AddFunc: rsc.addPod,
+			// This invokes the ReplicaSet for every pod change, eg: host assignment. Though this might seem like
+			// overkill the most frequent pod update is status, and the associated ReplicaSet will only list from
+			// local storage, so it should be ok.
+			UpdateFunc: rsc.updatePod,
+			DeleteFunc: rsc.deletePod,
+		},
+	)
+
+	rsc.syncHandler = rsc.syncReplicaSet
+	rsc.podStoreSynced = rsc.podController.HasSynced
+	return rsc
+}
+
+// SetEventRecorder replaces the event recorder used by the ReplicaSetController
+// with the given recorder. Only used for testing.
+func (rsc *ReplicaSetController) SetEventRecorder(recorder record.EventRecorder) {
+	// TODO: Hack. We can't cleanly shutdown the event recorder, so benchmarks
+	// need to pass in a fake.
+	rsc.podControl = controller.RealPodControl{KubeClient: rsc.kubeClient, Recorder: recorder}
+}
+
+// Run begins watching and syncing.
+func (rsc *ReplicaSetController) Run(workers int, stopCh <-chan struct{}) {
+	defer util.HandleCrash()
+	go rsc.rsController.Run(stopCh)
+	go rsc.podController.Run(stopCh)
+	for i := 0; i < workers; i++ {
+		go util.Until(rsc.worker, time.Second, stopCh)
+	}
+	<-stopCh
+	glog.Infof("Shutting down ReplicaSet Controller")
+	rsc.queue.ShutDown()
+}
+
+// getPodReplicaSet returns the replica set managing the given pod.
+// TODO: Surface that we are ignoring multiple replica sets for a single pod.
+func (rsc *ReplicaSetController) getPodReplicaSet(pod *api.Pod) *extensions.ReplicaSet {
+	rss, err := rsc.rsStore.GetPodReplicaSets(pod)
+	if err != nil {
+		glog.V(4).Infof("No ReplicaSets found for pod %v, ReplicaSet controller will avoid syncing", pod.Name)
+		return nil
+	}
+	// In theory, overlapping ReplicaSets is user error. This sorting will not prevent
+	// oscillation of replicas in all cases, eg:
+	// rs1 (older rs): [(k1=v1)], replicas=1 rs2: [(k2=v2)], replicas=2
+	// pod: [(k1:v1), (k2:v2)] will wake both rs1 and rs2, and we will sync rs1.
+	// pod: [(k2:v2)] will wake rs2 which creates a new replica.
+	if len(rss) > 1 {
+		// More than two items in this list indicates user error. If two replicasets
+		// overlap, sort by creation timestamp, subsort by name, then pick
+		// the first.
+		glog.Errorf("user error! more than one ReplicaSet is selecting pods with labels: %+v", pod.Labels)
+		sort.Sort(overlappingReplicaSets(rss))
+	}
+	return &rss[0]
+}
+
+// When a pod is created, enqueue the replica set that manages it and update it's expectations.
+func (rsc *ReplicaSetController) addPod(obj interface{}) {
+	pod := obj.(*api.Pod)
+	if pod.DeletionTimestamp != nil {
+		// on a restart of the controller manager, it's possible a new pod shows up in a state that
+		// is already pending deletion. Prevent the pod from being a creation observation.
+		rsc.deletePod(pod)
+		return
+	}
+	if rs := rsc.getPodReplicaSet(pod); rs != nil {
+		rsKey, err := controller.KeyFunc(rs)
+		if err != nil {
+			glog.Errorf("Couldn't get key for ReplicaSet %#v: %v", rs, err)
+			return
+		}
+		rsc.expectations.CreationObserved(rsKey)
+		rsc.enqueueReplicaSet(rs)
+	}
+}
+
+// When a pod is updated, figure out what replica set/s manage it and wake them
+// up. If the labels of the pod have changed we need to awaken both the old
+// and new replica set. old and cur must be *api.Pod types.
+func (rsc *ReplicaSetController) updatePod(old, cur interface{}) {
+	if api.Semantic.DeepEqual(old, cur) {
+		// A periodic relist will send update events for all known pods.
+		return
+	}
+	// TODO: Write a unittest for this case
+	curPod := cur.(*api.Pod)
+	if curPod.DeletionTimestamp != nil {
+		// when a pod is deleted gracefully it's deletion timestamp is first modified to reflect a grace period,
+		// and after such time has passed, the kubelet actually deletes it from the store. We receive an update
+		// for modification of the deletion timestamp and expect an ReplicaSet to create more replicas asap, not wait
+		// until the kubelet actually deletes the pod. This is different from the Phase of a pod changing, because
+		// a ReplicaSet never initiates a phase change, and so is never asleep waiting for the same.
+		rsc.deletePod(curPod)
+		return
+	}
+	if rs := rsc.getPodReplicaSet(curPod); rs != nil {
+		rsc.enqueueReplicaSet(rs)
+	}
+	oldPod := old.(*api.Pod)
+	// Only need to get the old replica set if the labels changed.
+	if !reflect.DeepEqual(curPod.Labels, oldPod.Labels) {
+		// If the old and new ReplicaSet are the same, the first one that syncs
+		// will set expectations preventing any damage from the second.
+		if oldRS := rsc.getPodReplicaSet(oldPod); oldRS != nil {
+			rsc.enqueueReplicaSet(oldRS)
+		}
+	}
+}
+
+// When a pod is deleted, enqueue the replica set that manages the pod and update its expectations.
+// obj could be an *api.Pod, or a DeletionFinalStateUnknown marker item.
+func (rsc *ReplicaSetController) deletePod(obj interface{}) {
+	pod, ok := obj.(*api.Pod)
+
+	// When a delete is dropped, the relist will notice a pod in the store not
+	// in the list, leading to the insertion of a tombstone object which contains
+	// the deleted key/value. Note that this value might be stale. If the pod
+	// changed labels the new ReplicaSet will not be woken up till the periodic resync.
+	if !ok {
+		tombstone, ok := obj.(cache.DeletedFinalStateUnknown)
+		if !ok {
+			glog.Errorf("Couldn't get object from tombstone %+v, could take up to %v before a replica set recreates a replica", obj, controller.ExpectationsTimeout)
+			return
+		}
+		pod, ok = tombstone.Obj.(*api.Pod)
+		if !ok {
+			glog.Errorf("Tombstone contained object that is not a pod %+v, could take up to %v before replica set recreates a replica", obj, controller.ExpectationsTimeout)
+			return
+		}
+	}
+	if rs := rsc.getPodReplicaSet(pod); rs != nil {
+		rsKey, err := controller.KeyFunc(rs)
+		if err != nil {
+			glog.Errorf("Couldn't get key for ReplicaSet %#v: %v", rs, err)
+			return
+		}
+		rsc.expectations.DeletionObserved(rsKey)
+		rsc.enqueueReplicaSet(rs)
+	}
+}
+
+// obj could be an *extensions.ReplicaSet, or a DeletionFinalStateUnknown marker item.
+func (rsc *ReplicaSetController) enqueueReplicaSet(obj interface{}) {
+	key, err := controller.KeyFunc(obj)
+	if err != nil {
+		glog.Errorf("Couldn't get key for object %+v: %v", obj, err)
+		return
+	}
+
+	// TODO: Handle overlapping replica sets better. Either disallow them at admission time or
+	// deterministically avoid syncing replica sets that fight over pods. Currently, we only
+	// ensure that the same replica set is synced for a given pod. When we periodically relist
+	// all replica sets there will still be some replica instability. One way to handle this is
+	// by querying the store for all replica sets that this replica set overlaps, as well as all
+	// replica sets that overlap this ReplicaSet, and sorting them.
+	rsc.queue.Add(key)
+}
+
+// worker runs a worker thread that just dequeues items, processes them, and marks them done.
+// It enforces that the syncHandler is never invoked concurrently with the same key.
+func (rsc *ReplicaSetController) worker() {
+	for {
+		func() {
+			key, quit := rsc.queue.Get()
+			if quit {
+				return
+			}
+			defer rsc.queue.Done(key)
+			err := rsc.syncHandler(key.(string))
+			if err != nil {
+				glog.Errorf("Error syncing ReplicaSet: %v", err)
+			}
+		}()
+	}
+}
+
+// manageReplicas checks and updates replicas for the given ReplicaSet.
+func (rsc *ReplicaSetController) manageReplicas(filteredPods []*api.Pod, rs *extensions.ReplicaSet) {
+	diff := len(filteredPods) - rs.Spec.Replicas
+	rsKey, err := controller.KeyFunc(rs)
+	if err != nil {
+		glog.Errorf("Couldn't get key for ReplicaSet %#v: %v", rs, err)
+		return
+	}
+	if diff < 0 {
+		diff *= -1
+		if diff > rsc.burstReplicas {
+			diff = rsc.burstReplicas
+		}
+		rsc.expectations.ExpectCreations(rsKey, diff)
+		wait := sync.WaitGroup{}
+		wait.Add(diff)
+		glog.V(2).Infof("Too few %q/%q replicas, need %d, creating %d", rs.Namespace, rs.Name, rs.Spec.Replicas, diff)
+		for i := 0; i < diff; i++ {
+			go func() {
+				defer wait.Done()
+				if err := rsc.podControl.CreatePods(rs.Namespace, rs.Spec.Template, rs); 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 replica set %q/%q", rs.Namespace, rs.Name)
+					rsc.expectations.CreationObserved(rsKey)
+					util.HandleError(err)
+				}
+			}()
+		}
+		wait.Wait()
+	} else if diff > 0 {
+		if diff > rsc.burstReplicas {
+			diff = rsc.burstReplicas
+		}
+		rsc.expectations.ExpectDeletions(rsKey, diff)
+		glog.V(2).Infof("Too many %q/%q replicas, need %d, deleting %d", rs.Namespace, rs.Name, rs.Spec.Replicas, diff)
+		// No need to sort pods if we are about to delete all of them
+		if rs.Spec.Replicas != 0 {
+			// Sort the pods in the order such that not-ready < ready, unscheduled
+			// < scheduled, and pending < running. This ensures that we delete pods
+			// in the earlier stages whenever possible.
+			sort.Sort(controller.ActivePods(filteredPods))
+		}
+
+		wait := sync.WaitGroup{}
+		wait.Add(diff)
+		for i := 0; i < diff; i++ {
+			go func(ix int) {
+				defer wait.Done()
+				if err := rsc.podControl.DeletePod(rs.Namespace, filteredPods[ix].Name, rs); err != nil {
+					// Decrement the expected number of deletes because the informer won't observe this deletion
+					glog.V(2).Infof("Failed deletion, decrementing expectations for replica set %q/%q", rs.Namespace, rs.Name)
+					rsc.expectations.DeletionObserved(rsKey)
+					util.HandleError(err)
+				}
+			}(i)
+		}
+		wait.Wait()
+	}
+}
+
+// syncReplicaSet will sync the ReplicaSet with the given key if it has had its expectations fulfilled,
+// meaning it did not expect to see any more of its pods created or deleted. This function is not meant to be
+// invoked concurrently with the same key.
+func (rsc *ReplicaSetController) syncReplicaSet(key string) error {
+	startTime := time.Now()
+	defer func() {
+		glog.V(4).Infof("Finished syncing replica set %q (%v)", key, time.Now().Sub(startTime))
+	}()
+
+	obj, exists, err := rsc.rsStore.Store.GetByKey(key)
+	if !exists {
+		glog.Infof("ReplicaSet has been deleted %v", key)
+		rsc.expectations.DeleteExpectations(key)
+		return nil
+	}
+	if err != nil {
+		glog.Infof("Unable to retrieve ReplicaSet %v from store: %v", key, err)
+		rsc.queue.Add(key)
+		return err
+	}
+	rs := *obj.(*extensions.ReplicaSet)
+	if !rsc.podStoreSynced() {
+		// Sleep so we give the pod reflector goroutine a chance to run.
+		time.Sleep(PodStoreSyncedPollPeriod)
+		glog.Infof("Waiting for pods controller to sync, requeuing ReplicaSet %v", rs.Name)
+		rsc.enqueueReplicaSet(&rs)
+		return nil
+	}
+
+	// Check the expectations of the ReplicaSet before counting active pods, otherwise a new pod can sneak
+	// in and update the expectations after we've retrieved active pods from the store. If a new pod enters
+	// the store after we've checked the expectation, the ReplicaSet sync is just deferred till the next
+	// relist.
+	rsKey, err := controller.KeyFunc(&rs)
+	if err != nil {
+		glog.Errorf("Couldn't get key for ReplicaSet %#v: %v", rs, err)
+		return err
+	}
+	rsNeedsSync := rsc.expectations.SatisfiedExpectations(rsKey)
+	selector, err := extensions.LabelSelectorAsSelector(rs.Spec.Selector)
+	if err != nil {
+		glog.Errorf("Error converting pod selector to selector: %v", err)
+		return err
+	}
+	podList, err := rsc.podStore.Pods(rs.Namespace).List(selector)
+	if err != nil {
+		glog.Errorf("Error getting pods for ReplicaSet %q: %v", key, err)
+		rsc.queue.Add(key)
+		return err
+	}
+
+	// TODO: Do this in a single pass, or use an index.
+	filteredPods := controller.FilterActivePods(podList.Items)
+	if rsNeedsSync {
+		rsc.manageReplicas(filteredPods, &rs)
+	}
+
+	// Always updates status as pods come up or die.
+	if err := updateReplicaCount(rsc.kubeClient.Extensions().ReplicaSets(rs.Namespace), rs, len(filteredPods)); err != nil {
+		// Multiple things could lead to this update failing. Requeuing the replica set ensures
+		// we retry with some fairness.
+		glog.V(2).Infof("Failed to update replica count for controller %v/%v; requeuing; error: %v", rs.Namespace, rs.Name, err)
+		rsc.enqueueReplicaSet(&rs)
+	}
+	return nil
+}

pkg/controller/replicaset/replica_set_test.go

@@ -0,0 +1,908 @@
+/*
+Copyright 2016 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// If you make changes to this file, you should also make the corresponding change in ReplicationController.
+
+package replicaset
+
+import (
+	"fmt"
+	"math/rand"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	"k8s.io/kubernetes/pkg/api"
+	"k8s.io/kubernetes/pkg/api/testapi"
+	"k8s.io/kubernetes/pkg/api/unversioned"
+	"k8s.io/kubernetes/pkg/apis/extensions"
+	"k8s.io/kubernetes/pkg/client/cache"
+	client "k8s.io/kubernetes/pkg/client/unversioned"
+	"k8s.io/kubernetes/pkg/client/unversioned/testclient"
+	"k8s.io/kubernetes/pkg/controller"
+	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/securitycontext"
+	"k8s.io/kubernetes/pkg/util"
+	"k8s.io/kubernetes/pkg/util/sets"
+	utiltesting "k8s.io/kubernetes/pkg/util/testing"
+	"k8s.io/kubernetes/pkg/watch"
+)
+
+var alwaysReady = func() bool { return true }
+
+func getKey(rs *extensions.ReplicaSet, t *testing.T) string {
+	if key, err := controller.KeyFunc(rs); err != nil {
+		t.Errorf("Unexpected error getting key for ReplicaSet %v: %v", rs.Name, err)
+		return ""
+	} else {
+		return key
+	}
+}
+
+func newReplicaSet(replicas int, selectorMap map[string]string) *extensions.ReplicaSet {
+	rs := &extensions.ReplicaSet{
+		TypeMeta: unversioned.TypeMeta{APIVersion: testapi.Default.GroupVersion().String()},
+		ObjectMeta: api.ObjectMeta{
+			UID:             util.NewUUID(),
+			Name:            "foobar",
+			Namespace:       api.NamespaceDefault,
+			ResourceVersion: "18",
+		},
+		Spec: extensions.ReplicaSetSpec{
+			Replicas: replicas,
+			Selector: &extensions.LabelSelector{MatchLabels: selectorMap},
+			Template: &api.PodTemplateSpec{
+				ObjectMeta: api.ObjectMeta{
+					Labels: map[string]string{
+						"name": "foo",
+						"type": "production",
+					},
+				},
+				Spec: api.PodSpec{
+					Containers: []api.Container{
+						{
+							Image: "foo/bar",
+							TerminationMessagePath: api.TerminationMessagePathDefault,
+							ImagePullPolicy:        api.PullIfNotPresent,
+							SecurityContext:        securitycontext.ValidSecurityContextWithContainerDefaults(),
+						},
+					},
+					RestartPolicy: api.RestartPolicyAlways,
+					DNSPolicy:     api.DNSDefault,
+					NodeSelector: map[string]string{
+						"baz": "blah",
+					},
+				},
+			},
+		},
+	}
+	return rs
+}
+
+// create count pods with the given phase for the given ReplicaSet (same selectors and namespace), and add them to the store.
+func newPodList(store cache.Store, count int, status api.PodPhase, labelMap map[string]string, rs *extensions.ReplicaSet) *api.PodList {
+	pods := []api.Pod{}
+	for i := 0; i < count; i++ {
+		newPod := api.Pod{
+			ObjectMeta: api.ObjectMeta{
+				Name:      fmt.Sprintf("pod%d", i),
+				Labels:    labelMap,
+				Namespace: rs.Namespace,
+			},
+			Status: api.PodStatus{Phase: status},
+		}
+		if store != nil {
+			store.Add(&newPod)
+		}
+		pods = append(pods, newPod)
+	}
+	return &api.PodList{
+		Items: pods,
+	}
+}
+
+func validateSyncReplicaSet(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))
+	}
+	if len(fakePodControl.DeletePodName) != expectedDeletes {
+		t.Errorf("Unexpected number of deletes.  Expected %d, saw %d\n", expectedDeletes, len(fakePodControl.DeletePodName))
+	}
+}
+
+func replicaSetResourceName() string {
+	return "replicasets"
+}
+
+type serverResponse struct {
+	statusCode int
+	obj        interface{}
+}
+
+func TestSyncReplicaSetDoesNothing(t *testing.T) {
+	client := client.NewOrDie(&client.Config{Host: "", ContentConfig: client.ContentConfig{GroupVersion: testapi.Default.GroupVersion()}})
+	fakePodControl := controller.FakePodControl{}
+	manager := NewReplicaSetController(client, controller.NoResyncPeriodFunc, BurstReplicas)
+	manager.podStoreSynced = alwaysReady
+
+	// 2 running pods, a controller with 2 replicas, sync is a no-op
+	labelMap := map[string]string{"foo": "bar"}
+	rsSpec := newReplicaSet(2, labelMap)
+	manager.rsStore.Store.Add(rsSpec)
+	newPodList(manager.podStore.Store, 2, api.PodRunning, labelMap, rsSpec)
+
+	manager.podControl = &fakePodControl
+	manager.syncReplicaSet(getKey(rsSpec, t))
+	validateSyncReplicaSet(t, &fakePodControl, 0, 0)
+}
+
+func TestSyncReplicaSetDeletes(t *testing.T) {
+	client := client.NewOrDie(&client.Config{Host: "", ContentConfig: client.ContentConfig{GroupVersion: testapi.Default.GroupVersion()}})
+	fakePodControl := controller.FakePodControl{}
+	manager := NewReplicaSetController(client, controller.NoResyncPeriodFunc, BurstReplicas)
+	manager.podStoreSynced = alwaysReady
+	manager.podControl = &fakePodControl
+
+	// 2 running pods and a controller with 1 replica, one pod delete expected
+	labelMap := map[string]string{"foo": "bar"}
+	rsSpec := newReplicaSet(1, labelMap)
+	manager.rsStore.Store.Add(rsSpec)
+	newPodList(manager.podStore.Store, 2, api.PodRunning, labelMap, rsSpec)
+
+	manager.syncReplicaSet(getKey(rsSpec, t))
+	validateSyncReplicaSet(t, &fakePodControl, 0, 1)
+}
+
+func TestDeleteFinalStateUnknown(t *testing.T) {
+	client := client.NewOrDie(&client.Config{Host: "", ContentConfig: client.ContentConfig{GroupVersion: testapi.Default.GroupVersion()}})
+	fakePodControl := controller.FakePodControl{}
+	manager := NewReplicaSetController(client, controller.NoResyncPeriodFunc, BurstReplicas)
+	manager.podStoreSynced = alwaysReady
+	manager.podControl = &fakePodControl
+
+	received := make(chan string)
+	manager.syncHandler = func(key string) error {
+		received <- key
+		return nil
+	}
+
+	// The DeletedFinalStateUnknown object should cause the ReplicaSet manager to insert
+	// the controller matching the selectors of the deleted pod into the work queue.
+	labelMap := map[string]string{"foo": "bar"}
+	rsSpec := newReplicaSet(1, labelMap)
+	manager.rsStore.Store.Add(rsSpec)
+	pods := newPodList(nil, 1, api.PodRunning, labelMap, rsSpec)
+	manager.deletePod(cache.DeletedFinalStateUnknown{Key: "foo", Obj: &pods.Items[0]})
+
+	go manager.worker()
+
+	expected := getKey(rsSpec, t)
+	select {
+	case key := <-received:
+		if key != expected {
+			t.Errorf("Unexpected sync all for ReplicaSet %v, expected %v", key, expected)
+		}
+	case <-time.After(util.ForeverTestTimeout):
+		t.Errorf("Processing DeleteFinalStateUnknown took longer than expected")
+	}
+}
+
+func TestSyncReplicaSetCreates(t *testing.T) {
+	client := client.NewOrDie(&client.Config{Host: "", ContentConfig: client.ContentConfig{GroupVersion: testapi.Default.GroupVersion()}})
+	manager := NewReplicaSetController(client, controller.NoResyncPeriodFunc, BurstReplicas)
+	manager.podStoreSynced = alwaysReady
+
+	// A controller with 2 replicas and no pods in the store, 2 creates expected
+	labelMap := map[string]string{"foo": "bar"}
+	rs := newReplicaSet(2, labelMap)
+	manager.rsStore.Store.Add(rs)
+
+	fakePodControl := controller.FakePodControl{}
+	manager.podControl = &fakePodControl
+	manager.syncReplicaSet(getKey(rs, t))
+	validateSyncReplicaSet(t, &fakePodControl, 2, 0)
+}
+
+func TestStatusUpdatesWithoutReplicasChange(t *testing.T) {
+	// Setup a fake server to listen for requests, and run the ReplicaSet controller in steady state
+	fakeHandler := utiltesting.FakeHandler{
+		StatusCode:   200,
+		ResponseBody: "",
+	}
+	testServer := httptest.NewServer(&fakeHandler)
+	defer testServer.Close()
+	client := client.NewOrDie(&client.Config{Host: testServer.URL, ContentConfig: client.ContentConfig{GroupVersion: testapi.Default.GroupVersion()}})
+	manager := NewReplicaSetController(client, controller.NoResyncPeriodFunc, BurstReplicas)
+	manager.podStoreSynced = alwaysReady
+
+	// Steady state for the ReplicaSet, no Status.Replicas updates expected
+	activePods := 5
+	labelMap := map[string]string{"foo": "bar"}
+	rs := newReplicaSet(activePods, labelMap)
+	manager.rsStore.Store.Add(rs)
+	rs.Status = extensions.ReplicaSetStatus{Replicas: activePods}
+	newPodList(manager.podStore.Store, activePods, api.PodRunning, labelMap, rs)
+
+	fakePodControl := controller.FakePodControl{}
+	manager.podControl = &fakePodControl
+	manager.syncReplicaSet(getKey(rs, t))
+
+	validateSyncReplicaSet(t, &fakePodControl, 0, 0)
+	if fakeHandler.RequestReceived != nil {
+		t.Errorf("Unexpected update when pods and ReplicaSets are in a steady state")
+	}
+
+	// This response body is just so we don't err out decoding the http response, all
+	// we care about is the request body sent below.
+	response := runtime.EncodeOrDie(testapi.Extensions.Codec(), &extensions.ReplicaSet{})
+	fakeHandler.ResponseBody = response
+
+	rs.Generation = rs.Generation + 1
+	manager.syncReplicaSet(getKey(rs, t))
+
+	rs.Status.ObservedGeneration = rs.Generation
+	updatedRc := runtime.EncodeOrDie(testapi.Extensions.Codec(), rs)
+	fakeHandler.ValidateRequest(t, testapi.Extensions.ResourcePath(replicaSetResourceName(), rs.Namespace, rs.Name)+"/status", "PUT", &updatedRc)
+}
+
+func TestControllerUpdateReplicas(t *testing.T) {
+	// This is a happy server just to record the PUT request we expect for status.Replicas
+	fakeHandler := utiltesting.FakeHandler{
+		StatusCode:   200,
+		ResponseBody: "",
+	}
+	testServer := httptest.NewServer(&fakeHandler)
+	defer testServer.Close()
+
+	client := client.NewOrDie(&client.Config{Host: testServer.URL, ContentConfig: client.ContentConfig{GroupVersion: testapi.Default.GroupVersion()}})
+	manager := NewReplicaSetController(client, controller.NoResyncPeriodFunc, BurstReplicas)
+	manager.podStoreSynced = alwaysReady
+
+	// Insufficient number of pods in the system, and Status.Replicas is wrong;
+	// Status.Replica should update to match number of pods in system, 1 new pod should be created.
+	labelMap := map[string]string{"foo": "bar"}
+	rs := newReplicaSet(5, labelMap)
+	manager.rsStore.Store.Add(rs)
+	rs.Status = extensions.ReplicaSetStatus{Replicas: 2, ObservedGeneration: 0}
+	rs.Generation = 1
+	newPodList(manager.podStore.Store, 4, api.PodRunning, labelMap, rs)
+
+	// This response body is just so we don't err out decoding the http response
+	response := runtime.EncodeOrDie(testapi.Extensions.Codec(), &extensions.ReplicaSet{})
+	fakeHandler.ResponseBody = response
+
+	fakePodControl := controller.FakePodControl{}
+	manager.podControl = &fakePodControl
+
+	manager.syncReplicaSet(getKey(rs, t))
+
+	// 1. Status.Replicas should go up from 2->4 even though we created 5-4=1 pod.
+	// 2. Every update to the status should include the Generation of the spec.
+	rs.Status = extensions.ReplicaSetStatus{Replicas: 4, ObservedGeneration: 1}
+
+	decRc := runtime.EncodeOrDie(testapi.Extensions.Codec(), rs)
+	fakeHandler.ValidateRequest(t, testapi.Extensions.ResourcePath(replicaSetResourceName(), rs.Namespace, rs.Name)+"/status", "PUT", &decRc)
+	validateSyncReplicaSet(t, &fakePodControl, 1, 0)
+}
+
+func TestSyncReplicaSetDormancy(t *testing.T) {
+	// Setup a test server so we can lie about the current state of pods
+	fakeHandler := utiltesting.FakeHandler{
+		StatusCode:   200,
+		ResponseBody: "",
+	}
+	testServer := httptest.NewServer(&fakeHandler)
+	defer testServer.Close()
+	client := client.NewOrDie(&client.Config{Host: testServer.URL, ContentConfig: client.ContentConfig{GroupVersion: testapi.Default.GroupVersion()}})
+
+	fakePodControl := controller.FakePodControl{}
+	manager := NewReplicaSetController(client, controller.NoResyncPeriodFunc, BurstReplicas)
+	manager.podStoreSynced = alwaysReady
+	manager.podControl = &fakePodControl
+
+	labelMap := map[string]string{"foo": "bar"}
+	rsSpec := newReplicaSet(2, labelMap)
+	manager.rsStore.Store.Add(rsSpec)
+	newPodList(manager.podStore.Store, 1, api.PodRunning, labelMap, rsSpec)
+
+	// Creates a replica and sets expectations
+	rsSpec.Status.Replicas = 1
+	manager.syncReplicaSet(getKey(rsSpec, t))
+	validateSyncReplicaSet(t, &fakePodControl, 1, 0)
+
+	// Expectations prevents replicas but not an update on status
+	rsSpec.Status.Replicas = 0
+	fakePodControl.Clear()
+	manager.syncReplicaSet(getKey(rsSpec, t))
+	validateSyncReplicaSet(t, &fakePodControl, 0, 0)
+
+	// Get the key for the controller
+	rsKey, err := controller.KeyFunc(rsSpec)
+	if err != nil {
+		t.Errorf("Couldn't get key for object %+v: %v", rsSpec, err)
+	}
+
+	// Lowering expectations should lead to a sync that creates a replica, however the
+	// fakePodControl error will prevent this, leaving expectations at 0, 0
+	manager.expectations.CreationObserved(rsKey)
+	rsSpec.Status.Replicas = 1
+	fakePodControl.Clear()
+	fakePodControl.Err = fmt.Errorf("Fake Error")
+
+	manager.syncReplicaSet(getKey(rsSpec, t))
+	validateSyncReplicaSet(t, &fakePodControl, 0, 0)
+
+	// This replica should not need a Lowering of expectations, since the previous create failed
+	fakePodControl.Err = nil
+	manager.syncReplicaSet(getKey(rsSpec, t))
+	validateSyncReplicaSet(t, &fakePodControl, 1, 0)
+
+	// 1 PUT for the ReplicaSet status during dormancy window.
+	// Note that the pod creates go through pod control so they're not recorded.
+	fakeHandler.ValidateRequestCount(t, 1)
+}
+
+func TestPodControllerLookup(t *testing.T) {
+	manager := NewReplicaSetController(client.NewOrDie(&client.Config{Host: "", ContentConfig: client.ContentConfig{GroupVersion: testapi.Default.GroupVersion()}}), controller.NoResyncPeriodFunc, BurstReplicas)
+	manager.podStoreSynced = alwaysReady
+	testCases := []struct {
+		inRSs     []*extensions.ReplicaSet
+		pod       *api.Pod
+		outRSName string
+	}{
+		// pods without labels don't match any ReplicaSets
+		{
+			inRSs: []*extensions.ReplicaSet{
+				{ObjectMeta: api.ObjectMeta{Name: "basic"}}},
+			pod:       &api.Pod{ObjectMeta: api.ObjectMeta{Name: "foo1", Namespace: api.NamespaceAll}},
+			outRSName: "",
+		},
+		// Matching labels, not namespace
+		{
+			inRSs: []*extensions.ReplicaSet{
+				{
+					ObjectMeta: api.ObjectMeta{Name: "foo"},
+					Spec: extensions.ReplicaSetSpec{
+						Selector: &extensions.LabelSelector{MatchLabels: map[string]string{"foo": "bar"}},
+					},
+				},
+			},
+			pod: &api.Pod{
+				ObjectMeta: api.ObjectMeta{
+					Name: "foo2", Namespace: "ns", Labels: map[string]string{"foo": "bar"}}},
+			outRSName: "",
+		},
+		// Matching ns and labels returns the key to the ReplicaSet, not the ReplicaSet name
+		{
+			inRSs: []*extensions.ReplicaSet{
+				{
+					ObjectMeta: api.ObjectMeta{Name: "bar", Namespace: "ns"},
+					Spec: extensions.ReplicaSetSpec{
+						Selector: &extensions.LabelSelector{MatchLabels: map[string]string{"foo": "bar"}},
+					},
+				},
+			},
+			pod: &api.Pod{
+				ObjectMeta: api.ObjectMeta{
+					Name: "foo3", Namespace: "ns", Labels: map[string]string{"foo": "bar"}}},
+			outRSName: "bar",
+		},
+	}
+	for _, c := range testCases {
+		for _, r := range c.inRSs {
+			manager.rsStore.Add(r)
+		}
+		if rs := manager.getPodReplicaSet(c.pod); rs != nil {
+			if c.outRSName != rs.Name {
+				t.Errorf("Got replica set %+v expected %+v", rs.Name, c.outRSName)
+			}
+		} else if c.outRSName != "" {
+			t.Errorf("Expected a replica set %v pod %v, found none", c.outRSName, c.pod.Name)
+		}
+	}
+}
+
+type FakeWatcher struct {
+	w *watch.FakeWatcher
+	*testclient.Fake
+}
+
+func TestWatchControllers(t *testing.T) {
+	fakeWatch := watch.NewFake()
+	client := &testclient.Fake{}
+	client.AddWatchReactor("*", testclient.DefaultWatchReactor(fakeWatch, nil))
+	manager := NewReplicaSetController(client, controller.NoResyncPeriodFunc, BurstReplicas)
+	manager.podStoreSynced = alwaysReady
+
+	var testRSSpec extensions.ReplicaSet
+	received := make(chan string)
+
+	// The update sent through the fakeWatcher should make its way into the workqueue,
+	// and eventually into the syncHandler. The handler validates the received controller
+	// and closes the received channel to indicate that the test can finish.
+	manager.syncHandler = func(key string) error {
+
+		obj, exists, err := manager.rsStore.Store.GetByKey(key)
+		if !exists || err != nil {
+			t.Errorf("Expected to find replica set under key %v", key)
+		}
+		rsSpec := *obj.(*extensions.ReplicaSet)
+		if !api.Semantic.DeepDerivative(rsSpec, testRSSpec) {
+			t.Errorf("Expected %#v, but got %#v", testRSSpec, rsSpec)
+		}
+		close(received)
+		return nil
+	}
+	// Start only the ReplicaSet watcher and the workqueue, send a watch event,
+	// and make sure it hits the sync method.
+	stopCh := make(chan struct{})
+	defer close(stopCh)
+	go manager.rsController.Run(stopCh)
+	go util.Until(manager.worker, 10*time.Millisecond, stopCh)
+
+	testRSSpec.Name = "foo"
+	fakeWatch.Add(&testRSSpec)
+
+	select {
+	case <-received:
+	case <-time.After(util.ForeverTestTimeout):
+		t.Errorf("Expected 1 call but got 0")
+	}
+}
+
+func TestWatchPods(t *testing.T) {
+	fakeWatch := watch.NewFake()
+	client := &testclient.Fake{}
+	client.AddWatchReactor("*", testclient.DefaultWatchReactor(fakeWatch, nil))
+	manager := NewReplicaSetController(client, controller.NoResyncPeriodFunc, BurstReplicas)
+	manager.podStoreSynced = alwaysReady
+
+	// Put one ReplicaSet and one pod into the controller's stores
+	labelMap := map[string]string{"foo": "bar"}
+	testRSSpec := newReplicaSet(1, labelMap)
+	manager.rsStore.Store.Add(testRSSpec)
+	received := make(chan string)
+	// The pod update sent through the fakeWatcher should figure out the managing ReplicaSet and
+	// send it into the syncHandler.
+	manager.syncHandler = func(key string) error {
+
+		obj, exists, err := manager.rsStore.Store.GetByKey(key)
+		if !exists || err != nil {
+			t.Errorf("Expected to find replica set under key %v", key)
+		}
+		rsSpec := obj.(*extensions.ReplicaSet)
+		if !api.Semantic.DeepDerivative(rsSpec, testRSSpec) {
+			t.Errorf("\nExpected %#v,\nbut got %#v", testRSSpec, rsSpec)
+		}
+		close(received)
+		return nil
+	}
+	// Start only the pod watcher and the workqueue, send a watch event,
+	// and make sure it hits the sync method for the right ReplicaSet.
+	stopCh := make(chan struct{})
+	defer close(stopCh)
+	go manager.podController.Run(stopCh)
+	go util.Until(manager.worker, 10*time.Millisecond, stopCh)
+
+	pods := newPodList(nil, 1, api.PodRunning, labelMap, testRSSpec)
+	testPod := pods.Items[0]
+	testPod.Status.Phase = api.PodFailed
+	fakeWatch.Add(&testPod)
+
+	select {
+	case <-received:
+	case <-time.After(util.ForeverTestTimeout):
+		t.Errorf("Expected 1 call but got 0")
+	}
+}
+
+func TestUpdatePods(t *testing.T) {
+	manager := NewReplicaSetController(testclient.NewSimpleFake(), controller.NoResyncPeriodFunc, BurstReplicas)
+	manager.podStoreSynced = alwaysReady
+
+	received := make(chan string)
+
+	manager.syncHandler = func(key string) error {
+		obj, exists, err := manager.rsStore.Store.GetByKey(key)
+		if !exists || err != nil {
+			t.Errorf("Expected to find replica set under key %v", key)
+		}
+		received <- obj.(*extensions.ReplicaSet).Name
+		return nil
+	}
+
+	stopCh := make(chan struct{})
+	defer close(stopCh)
+	go util.Until(manager.worker, 10*time.Millisecond, stopCh)
+
+	// Put 2 ReplicaSets and one pod into the controller's stores
+	labelMap1 := map[string]string{"foo": "bar"}
+	testRSSpec1 := newReplicaSet(1, labelMap1)
+	manager.rsStore.Store.Add(testRSSpec1)
+	testRSSpec2 := *testRSSpec1
+	labelMap2 := map[string]string{"bar": "foo"}
+	testRSSpec2.Spec.Selector = &extensions.LabelSelector{MatchLabels: labelMap2}
+	testRSSpec2.Name = "barfoo"
+	manager.rsStore.Store.Add(&testRSSpec2)
+
+	// Put one pod in the podStore
+	pod1 := newPodList(manager.podStore.Store, 1, api.PodRunning, labelMap1, testRSSpec1).Items[0]
+	pod2 := pod1
+	pod2.Labels = labelMap2
+
+	// Send an update of the same pod with modified labels, and confirm we get a sync request for
+	// both controllers
+	manager.updatePod(&pod1, &pod2)
+
+	expected := sets.NewString(testRSSpec1.Name, testRSSpec2.Name)
+	for _, name := range expected.List() {
+		t.Logf("Expecting update for %+v", name)
+		select {
+		case got := <-received:
+			if !expected.Has(got) {
+				t.Errorf("Expected keys %#v got %v", expected, got)
+			}
+		case <-time.After(util.ForeverTestTimeout):
+			t.Errorf("Expected update notifications for replica sets within 100ms each")
+		}
+	}
+}
+
+func TestControllerUpdateRequeue(t *testing.T) {
+	// This server should force a requeue of the controller because it fails to update status.Replicas.
+	fakeHandler := utiltesting.FakeHandler{
+		StatusCode:   500,
+		ResponseBody: "",
+	}
+	testServer := httptest.NewServer(&fakeHandler)
+	defer testServer.Close()
+
+	client := client.NewOrDie(&client.Config{Host: testServer.URL, ContentConfig: client.ContentConfig{GroupVersion: testapi.Default.GroupVersion()}})
+	manager := NewReplicaSetController(client, controller.NoResyncPeriodFunc, BurstReplicas)
+	manager.podStoreSynced = alwaysReady
+
+	labelMap := map[string]string{"foo": "bar"}
+	rs := newReplicaSet(1, labelMap)
+	manager.rsStore.Store.Add(rs)
+	rs.Status = extensions.ReplicaSetStatus{Replicas: 2}
+	newPodList(manager.podStore.Store, 1, api.PodRunning, labelMap, rs)
+
+	fakePodControl := controller.FakePodControl{}
+	manager.podControl = &fakePodControl
+
+	manager.syncReplicaSet(getKey(rs, t))
+
+	ch := make(chan interface{})
+	go func() {
+		item, _ := manager.queue.Get()
+		ch <- item
+	}()
+	select {
+	case key := <-ch:
+		expectedKey := getKey(rs, t)
+		if key != expectedKey {
+			t.Errorf("Expected requeue of replica set with key %s got %s", expectedKey, key)
+		}
+	case <-time.After(util.ForeverTestTimeout):
+		manager.queue.ShutDown()
+		t.Errorf("Expected to find a ReplicaSet in the queue, found none.")
+	}
+	// 1 Update and 1 GET, both of which fail
+	fakeHandler.ValidateRequestCount(t, 2)
+}
+
+func TestControllerUpdateStatusWithFailure(t *testing.T) {
+	rs := newReplicaSet(1, map[string]string{"foo": "bar"})
+	fakeClient := &testclient.FakeExperimental{Fake: &testclient.Fake{}}
+	fakeClient.AddReactor("get", "replicasets", func(action testclient.Action) (bool, runtime.Object, error) { return true, rs, nil })
+	fakeClient.AddReactor("*", "*", func(action testclient.Action) (bool, runtime.Object, error) {
+		return true, &extensions.ReplicaSet{}, fmt.Errorf("Fake error")
+	})
+	fakeRSClient := &testclient.FakeReplicaSets{fakeClient, "default"}
+	numReplicas := 10
+	updateReplicaCount(fakeRSClient, *rs, numReplicas)
+	updates, gets := 0, 0
+	for _, a := range fakeClient.Actions() {
+		if a.GetResource() != "replicasets" {
+			t.Errorf("Unexpected action %+v", a)
+			continue
+		}
+
+		switch action := a.(type) {
+		case testclient.GetAction:
+			gets++
+			// Make sure the get is for the right ReplicaSet even though the update failed.
+			if action.GetName() != rs.Name {
+				t.Errorf("Expected get for ReplicaSet %v, got %+v instead", rs.Name, action.GetName())
+			}
+		case testclient.UpdateAction:
+			updates++
+			// Confirm that the update has the right status.Replicas even though the Get
+			// returned a ReplicaSet with replicas=1.
+			if c, ok := action.GetObject().(*extensions.ReplicaSet); !ok {
+				t.Errorf("Expected a ReplicaSet as the argument to update, got %T", c)
+			} else if c.Status.Replicas != numReplicas {
+				t.Errorf("Expected update for ReplicaSet to contain replicas %v, got %v instead",
+					numReplicas, c.Status.Replicas)
+			}
+		default:
+			t.Errorf("Unexpected action %+v", a)
+			break
+		}
+	}
+	if gets != 1 || updates != 2 {
+		t.Errorf("Expected 1 get and 2 updates, got %d gets %d updates", gets, updates)
+	}
+}
+
+func doTestControllerBurstReplicas(t *testing.T, burstReplicas, numReplicas int) {
+	client := client.NewOrDie(&client.Config{Host: "", ContentConfig: client.ContentConfig{GroupVersion: testapi.Default.GroupVersion()}})
+	fakePodControl := controller.FakePodControl{}
+	manager := NewReplicaSetController(client, controller.NoResyncPeriodFunc, burstReplicas)
+	manager.podStoreSynced = alwaysReady
+	manager.podControl = &fakePodControl
+
+	labelMap := map[string]string{"foo": "bar"}
+	rsSpec := newReplicaSet(numReplicas, labelMap)
+	manager.rsStore.Store.Add(rsSpec)
+
+	expectedPods := 0
+	pods := newPodList(nil, numReplicas, api.PodPending, labelMap, rsSpec)
+
+	rsKey, err := controller.KeyFunc(rsSpec)
+	if err != nil {
+		t.Errorf("Couldn't get key for object %+v: %v", rsSpec, err)
+	}
+
+	// Size up the controller, then size it down, and confirm the expected create/delete pattern
+	for _, replicas := range []int{numReplicas, 0} {
+
+		rsSpec.Spec.Replicas = replicas
+		manager.rsStore.Store.Add(rsSpec)
+
+		for i := 0; i < numReplicas; i += burstReplicas {
+			manager.syncReplicaSet(getKey(rsSpec, t))
+
+			// The store accrues active pods. It's also used by the ReplicaSet to determine how many
+			// replicas to create.
+			activePods := len(manager.podStore.Store.List())
+			if replicas != 0 {
+				// This is the number of pods currently "in flight". They were created by the
+				// ReplicaSet controller above, which then puts the ReplicaSet to sleep till
+				// all of them have been observed.
+				expectedPods = replicas - activePods
+				if expectedPods > burstReplicas {
+					expectedPods = burstReplicas
+				}
+				// This validates the ReplicaSet manager sync actually created pods
+				validateSyncReplicaSet(t, &fakePodControl, expectedPods, 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.
+				for i := 0; i < expectedPods-1; i++ {
+					manager.podStore.Store.Add(&pods.Items[i])
+					manager.addPod(&pods.Items[i])
+				}
+
+				podExp, exists, err := manager.expectations.GetExpectations(rsKey)
+				if !exists || err != nil {
+					t.Fatalf("Did not find expectations for ReplicaSet.")
+				}
+				if add, _ := podExp.GetExpectations(); add != 1 {
+					t.Fatalf("Expectations are wrong %v", podExp)
+				}
+			} else {
+				expectedPods = (replicas - activePods) * -1
+				if expectedPods > burstReplicas {
+					expectedPods = burstReplicas
+				}
+				validateSyncReplicaSet(t, &fakePodControl, 0, expectedPods)
+				for i := 0; i < expectedPods-1; i++ {
+					manager.podStore.Store.Delete(&pods.Items[i])
+					manager.deletePod(&pods.Items[i])
+				}
+				podExp, exists, err := manager.expectations.GetExpectations(rsKey)
+				if !exists || err != nil {
+					t.Fatalf("Did not find expectations for ReplicaSet.")
+				}
+				if _, del := podExp.GetExpectations(); del != 1 {
+					t.Fatalf("Expectations are wrong %v", podExp)
+				}
+			}
+
+			// Check that the ReplicaSet didn't take any action for all the above pods
+			fakePodControl.Clear()
+			manager.syncReplicaSet(getKey(rsSpec, t))
+			validateSyncReplicaSet(t, &fakePodControl, 0, 0)
+
+			// Create/Delete the last pod
+			// The last add pod will decrease the expectation of the ReplicaSet to 0,
+			// which will cause it to create/delete the remaining replicas up to burstReplicas.
+			if replicas != 0 {
+				manager.podStore.Store.Add(&pods.Items[expectedPods-1])
+				manager.addPod(&pods.Items[expectedPods-1])
+			} else {
+				manager.podStore.Store.Delete(&pods.Items[expectedPods-1])
+				manager.deletePod(&pods.Items[expectedPods-1])
+			}
+			pods.Items = pods.Items[expectedPods:]
+		}
+
+		// Confirm that we've created the right number of replicas
+		activePods := len(manager.podStore.Store.List())
+		if activePods != rsSpec.Spec.Replicas {
+			t.Fatalf("Unexpected number of active pods, expected %d, got %d", rsSpec.Spec.Replicas, activePods)
+		}
+		// Replenish the pod list, since we cut it down sizing up
+		pods = newPodList(nil, replicas, api.PodRunning, labelMap, rsSpec)
+	}
+}
+
+func TestControllerBurstReplicas(t *testing.T) {
+	doTestControllerBurstReplicas(t, 5, 30)
+	doTestControllerBurstReplicas(t, 5, 12)
+	doTestControllerBurstReplicas(t, 3, 2)
+}
+
+type FakeRSExpectations struct {
+	*controller.ControllerExpectations
+	satisfied    bool
+	expSatisfied func()
+}
+
+func (fe FakeRSExpectations) SatisfiedExpectations(controllerKey string) bool {
+	fe.expSatisfied()
+	return fe.satisfied
+}
+
+// TestRSSyncExpectations tests that a pod cannot sneak in between counting active pods
+// and checking expectations.
+func TestRSSyncExpectations(t *testing.T) {
+	client := client.NewOrDie(&client.Config{Host: "", ContentConfig: client.ContentConfig{GroupVersion: testapi.Default.GroupVersion()}})
+	fakePodControl := controller.FakePodControl{}
+	manager := NewReplicaSetController(client, controller.NoResyncPeriodFunc, 2)
+	manager.podStoreSynced = alwaysReady
+	manager.podControl = &fakePodControl
+
+	labelMap := map[string]string{"foo": "bar"}
+	rsSpec := newReplicaSet(2, labelMap)
+	manager.rsStore.Store.Add(rsSpec)
+	pods := newPodList(nil, 2, api.PodPending, labelMap, rsSpec)
+	manager.podStore.Store.Add(&pods.Items[0])
+	postExpectationsPod := pods.Items[1]
+
+	manager.expectations = FakeRSExpectations{
+		controller.NewControllerExpectations(), true, func() {
+			// If we check active pods before checking expectataions, the
+			// ReplicaSet will create a new replica because it doesn't see
+			// this pod, but has fulfilled its expectations.
+			manager.podStore.Store.Add(&postExpectationsPod)
+		},
+	}
+	manager.syncReplicaSet(getKey(rsSpec, t))
+	validateSyncReplicaSet(t, &fakePodControl, 0, 0)
+}
+
+func TestDeleteControllerAndExpectations(t *testing.T) {
+	client := client.NewOrDie(&client.Config{Host: "", ContentConfig: client.ContentConfig{GroupVersion: testapi.Default.GroupVersion()}})
+	manager := NewReplicaSetController(client, controller.NoResyncPeriodFunc, 10)
+	manager.podStoreSynced = alwaysReady
+
+	rs := newReplicaSet(1, map[string]string{"foo": "bar"})
+	manager.rsStore.Store.Add(rs)
+
+	fakePodControl := controller.FakePodControl{}
+	manager.podControl = &fakePodControl
+
+	// This should set expectations for the ReplicaSet
+	manager.syncReplicaSet(getKey(rs, t))
+	validateSyncReplicaSet(t, &fakePodControl, 1, 0)
+	fakePodControl.Clear()
+
+	// Get the ReplicaSet key
+	rsKey, err := controller.KeyFunc(rs)
+	if err != nil {
+		t.Errorf("Couldn't get key for object %+v: %v", rs, err)
+	}
+
+	// This is to simulate a concurrent addPod, that has a handle on the expectations
+	// as the controller deletes it.
+	podExp, exists, err := manager.expectations.GetExpectations(rsKey)
+	if !exists || err != nil {
+		t.Errorf("No expectations found for ReplicaSet")
+	}
+	manager.rsStore.Delete(rs)
+	manager.syncReplicaSet(getKey(rs, t))
+
+	if _, exists, err = manager.expectations.GetExpectations(rsKey); exists {
+		t.Errorf("Found expectaions, expected none since the ReplicaSet has been deleted.")
+	}
+
+	// This should have no effect, since we've deleted the ReplicaSet.
+	podExp.Seen(1, 0)
+	manager.podStore.Store.Replace(make([]interface{}, 0), "0")
+	manager.syncReplicaSet(getKey(rs, t))
+	validateSyncReplicaSet(t, &fakePodControl, 0, 0)
+}
+
+func TestRSManagerNotReady(t *testing.T) {
+	client := client.NewOrDie(&client.Config{Host: "", ContentConfig: client.ContentConfig{GroupVersion: testapi.Default.GroupVersion()}})
+	fakePodControl := controller.FakePodControl{}
+	manager := NewReplicaSetController(client, controller.NoResyncPeriodFunc, 2)
+	manager.podControl = &fakePodControl
+	manager.podStoreSynced = func() bool { return false }
+
+	// Simulates the ReplicaSet reflector running before the pod reflector. We don't
+	// want to end up creating replicas in this case until the pod reflector
+	// has synced, so the ReplicaSet controller should just requeue the ReplicaSet.
+	rsSpec := newReplicaSet(1, map[string]string{"foo": "bar"})
+	manager.rsStore.Store.Add(rsSpec)
+
+	rsKey := getKey(rsSpec, t)
+	manager.syncReplicaSet(rsKey)
+	validateSyncReplicaSet(t, &fakePodControl, 0, 0)
+	queueRS, _ := manager.queue.Get()
+	if queueRS != rsKey {
+		t.Fatalf("Expected to find key %v in queue, found %v", rsKey, queueRS)
+	}
+
+	manager.podStoreSynced = alwaysReady
+	manager.syncReplicaSet(rsKey)
+	validateSyncReplicaSet(t, &fakePodControl, 1, 0)
+}
+
+// shuffle returns a new shuffled list of container controllers.
+func shuffle(controllers []*extensions.ReplicaSet) []*extensions.ReplicaSet {
+	numControllers := len(controllers)
+	randIndexes := rand.Perm(numControllers)
+	shuffled := make([]*extensions.ReplicaSet, numControllers)
+	for i := 0; i < numControllers; i++ {
+		shuffled[i] = controllers[randIndexes[i]]
+	}
+	return shuffled
+}
+
+func TestOverlappingRSs(t *testing.T) {
+	client := client.NewOrDie(&client.Config{Host: "", ContentConfig: client.ContentConfig{GroupVersion: testapi.Default.GroupVersion()}})
+	labelMap := map[string]string{"foo": "bar"}
+
+	for i := 0; i < 5; i++ {
+		manager := NewReplicaSetController(client, controller.NoResyncPeriodFunc, 10)
+		manager.podStoreSynced = alwaysReady
+
+		// Create 10 ReplicaSets, shuffled them randomly and insert them into the ReplicaSet controller's store
+		var controllers []*extensions.ReplicaSet
+		for j := 1; j < 10; j++ {
+			rsSpec := newReplicaSet(1, labelMap)
+			rsSpec.CreationTimestamp = unversioned.Date(2014, time.December, j, 0, 0, 0, 0, time.Local)
+			rsSpec.Name = string(util.NewUUID())
+			controllers = append(controllers, rsSpec)
+		}
+		shuffledControllers := shuffle(controllers)
+		for j := range shuffledControllers {
+			manager.rsStore.Store.Add(shuffledControllers[j])
+		}
+		// Add a pod and make sure only the oldest ReplicaSet is synced
+		pods := newPodList(nil, 1, api.PodPending, labelMap, controllers[0])
+		rsKey := getKey(controllers[0], t)
+
+		manager.addPod(&pods.Items[0])
+		queueRS, _ := manager.queue.Get()
+		if queueRS != rsKey {
+			t.Fatalf("Expected to find key %v in queue, found %v", rsKey, queueRS)
+		}
+	}
+}

pkg/controller/replicaset/replica_set_utils.go

@@ -0,0 +1,72 @@
+/*
+Copyright 2016 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// If you make changes to this file, you should also make the corresponding change in ReplicationController.
+
+package replicaset
+
+import (
+	"github.com/golang/glog"
+	"k8s.io/kubernetes/pkg/apis/extensions"
+	client "k8s.io/kubernetes/pkg/client/unversioned"
+)
+
+// updateReplicaCount attempts to update the Status.Replicas of the given ReplicaSet, with a single GET/PUT retry.
+func updateReplicaCount(rsClient client.ReplicaSetInterface, rs extensions.ReplicaSet, numReplicas int) (updateErr error) {
+	// This is the steady state. It happens when the ReplicaSet doesn't have any expectations, since
+	// we do a periodic relist every 30s. If the generations differ but the replicas are
+	// the same, a caller might've resized to the same replica count.
+	if rs.Status.Replicas == numReplicas &&
+		rs.Generation == rs.Status.ObservedGeneration {
+		return nil
+	}
+	// Save the generation number we acted on, otherwise we might wrongfully indicate
+	// that we've seen a spec update when we retry.
+	// TODO: This can clobber an update if we allow multiple agents to write to the
+	// same status.
+	generation := rs.Generation
+
+	var getErr error
+	for i, rs := 0, &rs; ; i++ {
+		glog.V(4).Infof("Updating replica count for ReplicaSet: %v, %d->%d (need %d), sequence No: %v->%v",
+			rs.Name, rs.Status.Replicas, numReplicas, rs.Spec.Replicas, rs.Status.ObservedGeneration, generation)
+
+		rs.Status = extensions.ReplicaSetStatus{Replicas: numReplicas, ObservedGeneration: generation}
+		_, updateErr = rsClient.UpdateStatus(rs)
+		if updateErr == nil || i >= statusUpdateRetries {
+			return updateErr
+		}
+		// Update the ReplicaSet with the latest resource version for the next poll
+		if rs, getErr = rsClient.Get(rs.Name); getErr != nil {
+			// If the GET fails we can't trust status.Replicas anymore. This error
+			// is bound to be more interesting than the update failure.
+			return getErr
+		}
+	}
+}
+
+// overlappingReplicaSets sorts a list of ReplicaSets by creation timestamp, using their names as a tie breaker.
+type overlappingReplicaSets []extensions.ReplicaSet
+
+func (o overlappingReplicaSets) Len() int      { return len(o) }
+func (o overlappingReplicaSets) Swap(i, j int) { o[i], o[j] = o[j], o[i] }
+
+func (o overlappingReplicaSets) Less(i, j int) bool {
+	if o[i].CreationTimestamp.Equal(o[j].CreationTimestamp) {
+		return o[i].Name < o[j].Name
+	}
+	return o[i].CreationTimestamp.Before(o[j].CreationTimestamp)
+}

pkg/controller/replication/replication_controller.go

@@ -14,6 +14,8 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+// If you make changes to this file, you should also make the corresponding change in ReplicaSet.
+
 package replication
 
 import (

pkg/controller/replication/replication_controller_test.go

@@ -14,6 +14,8 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+// If you make changes to this file, you should also make the corresponding change in ReplicaSet.
+
 package replication
 
 import (

pkg/controller/replication/replication_controller_utils.go

@@ -14,6 +14,8 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+// If you make changes to this file, you should also make the corresponding change in ReplicaSet.
+
 package replication
 
 import (