// When a pod is deleted, enqueue the controller that manages the pod and update its expectations.
// obj could be an *api.Pod, or a DeletionFinalStateUnknown marker item.
func (rm *ReplicationManager) 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 rc 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 controller 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 controller recreates a replica", obj, controller.ExpectationsTimeout)
return
}
}
if rc := rm.getPodController(pod); rc != nil {
rcKey, err := controller.KeyFunc(rc)
if err != nil {
glog.Errorf("Couldn't get key for replication controller %#v: %v", rc, err)
return
}
rm.expectations.DeletionObserved(rcKey)
rm.enqueueController(rc)
}
}
func getKey(rc *api.ReplicationController, t *testing.T) string {
if key, err := controller.KeyFunc(rc); err != nil {
t.Errorf("Unexpected error getting key for rc %v: %v", rc.Name, err)
return ""
} else {
return key
}
}
// syncReplicationController will sync the rc 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 (rm *ReplicationManager) syncReplicationController(key string) error {
startTime := time.Now()
defer func() {
glog.V(4).Infof("Finished syncing controller %q (%v)", key, time.Now().Sub(startTime))
}()
obj, exists, err := rm.rcStore.Store.GetByKey(key)
if !exists {
glog.Infof("Replication Controller has been deleted %v", key)
rm.expectations.DeleteExpectations(key)
return nil
}
if err != nil {
glog.Infof("Unable to retrieve rc %v from store: %v", key, err)
rm.queue.Add(key)
return err
}
rc := *obj.(*api.ReplicationController)
if !rm.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 rc %v", rc.Name)
rm.enqueueController(&rc)
return nil
}
// Check the expectations of the rc 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 rc sync is just deferred till the next relist.
rcKey, err := controller.KeyFunc(&rc)
if err != nil {
glog.Errorf("Couldn't get key for replication controller %#v: %v", rc, err)
return err
}
rcNeedsSync := rm.expectations.SatisfiedExpectations(rcKey)
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
}
// TODO: Do this in a single pass, or use an index.
filteredPods := controller.FilterActivePods(podList.Items)
if rcNeedsSync {
rm.manageReplicas(filteredPods, &rc)
}
// Always updates status as pods come up or die.
if err := updateReplicaCount(rm.kubeClient.ReplicationControllers(rc.Namespace), rc, len(filteredPods)); err != nil {
// Multiple things could lead to this update failing. Requeuing the controller ensures
// we retry with some fairness.
glog.V(2).Infof("Failed to update replica count for controller %v, requeuing", rc.Name)
rm.enqueueController(&rc)
}
return nil
}
// manageReplicas checks and updates replicas for the given replication controller.
func (rm *ReplicationManager) manageReplicas(filteredPods []*api.Pod, rc *api.ReplicationController) {
diff := len(filteredPods) - rc.Spec.Replicas
rcKey, err := controller.KeyFunc(rc)
if err != nil {
glog.Errorf("Couldn't get key for replication controller %#v: %v", rc, err)
return
}
if diff < 0 {
diff *= -1
if diff > rm.burstReplicas {
diff = rm.burstReplicas
}
rm.expectations.ExpectCreations(rcKey, diff)
wait := sync.WaitGroup{}
wait.Add(diff)
glog.V(2).Infof("Too few %q/%q replicas, need %d, creating %d", rc.Namespace, rc.Name, rc.Spec.Replicas, diff)
for i := 0; i < diff; i++ {
go func() {
defer wait.Done()
if err := rm.podControl.CreateReplica(rc.Namespace, rc); 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)
util.HandleError(err)
}
}()
}
wait.Wait()
} else if diff > 0 {
if diff > rm.burstReplicas {
diff = rm.burstReplicas
}
rm.expectations.ExpectDeletions(rcKey, diff)
glog.V(2).Infof("Too many %q/%q replicas, need %d, deleting %d", rc.Namespace, rc.Name, rc.Spec.Replicas, diff)
// No need to sort pods if we are about to delete all of them
if rc.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 := rm.podControl.DeletePod(rc.Namespace, filteredPods[ix].Name); 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 controller %q/%q", rc.Namespace, rc.Name)
rm.expectations.DeletionObserved(rcKey)
}
}(i)
}
wait.Wait()
}
}
func TestSyncReplicationControllerDormancy(t *testing.T) {
// Setup a test server so we can lie about the current state of pods
fakeHandler := util.FakeHandler{
StatusCode: 200,
ResponseBody: "",
}
testServer := httptest.NewServer(&fakeHandler)
defer testServer.Close()
client := client.NewOrDie(&client.Config{Host: testServer.URL, Version: testapi.Version()})
fakePodControl := FakePodControl{}
manager := NewReplicationManager(client, BurstReplicas)
manager.podStoreSynced = alwaysReady
manager.podControl = &fakePodControl
controllerSpec := newReplicationController(2)
manager.rcStore.Store.Add(controllerSpec)
newPodList(manager.podStore.Store, 1, api.PodRunning, controllerSpec)
// Creates a replica and sets expectations
controllerSpec.Status.Replicas = 1
manager.syncReplicationController(getKey(controllerSpec, t))
validateSyncReplication(t, &fakePodControl, 1, 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)
// Get the key for the controller
rcKey, err := controller.KeyFunc(controllerSpec)
if err != nil {
t.Errorf("Couldn't get key for object %+v: %v", controllerSpec, 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(rcKey)
controllerSpec.Status.Replicas = 1
fakePodControl.clear()
fakePodControl.err = fmt.Errorf("Fake Error")
manager.syncReplicationController(getKey(controllerSpec, t))
validateSyncReplication(t, &fakePodControl, 0, 0)
// This replica should not need a Lowering of expectations, since the previous create failed
fakePodControl.err = nil
manager.syncReplicationController(getKey(controllerSpec, t))
validateSyncReplication(t, &fakePodControl, 1, 0)
// 1 PUT for the rc status during dormancy window.
// Note that the pod creates go through pod control so they're not recorded.
fakeHandler.ValidateRequestCount(t, 1)
}
// 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)
if rc := rm.getPodController(pod); rc != nil {
rcKey, err := controller.KeyFunc(rc)
if err != nil {
glog.Errorf("Couldn't get key for replication controller %#v: %v", rc, err)
return
}
rm.expectations.CreationObserved(rcKey)
rm.enqueueController(rc)
}
}
// obj could be an *api.ReplicationController, or a DeletionFinalStateUnknown marker item.
func (rm *ReplicationManager) enqueueController(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 controllers better. Either disallow them at admission time or
// deterministically avoid syncing controllers that fight over pods. Currently, we only
// ensure that the same controller is synced for a given pod. When we periodically relist
// all controllers there will still be some replica instability. One way to handle this is
// by querying the store for all controllers that this rc overlaps, as well as all
// controllers that overlap this rc, and sorting them.
rm.queue.Add(key)
}
func TestDeleteControllerAndExpectations(t *testing.T) {
client := client.NewOrDie(&client.Config{Host: "", Version: testapi.Version()})
manager := NewReplicationManager(client, 10)
manager.podStoreSynced = alwaysReady
rc := newReplicationController(1)
manager.rcStore.Store.Add(rc)
fakePodControl := FakePodControl{}
manager.podControl = &fakePodControl
// This should set expectations for the rc
manager.syncReplicationController(getKey(rc, t))
validateSyncReplication(t, &fakePodControl, 1, 0)
fakePodControl.clear()
// Get the RC key
rcKey, err := controller.KeyFunc(rc)
if err != nil {
t.Errorf("Couldn't get key for object %+v: %v", rc, 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(rcKey)
if !exists || err != nil {
t.Errorf("No expectations found for rc")
}
manager.rcStore.Delete(rc)
manager.syncReplicationController(getKey(rc, t))
if _, exists, err = manager.expectations.GetExpectations(rcKey); exists {
t.Errorf("Found expectaions, expected none since the rc has been deleted.")
}
// This should have no effect, since we've deleted the rc.
podExp.Seen(1, 0)
manager.podStore.Store.Replace(make([]interface{}, 0))
manager.syncReplicationController(getKey(rc, t))
validateSyncReplication(t, &fakePodControl, 0, 0)
}
func doTestControllerBurstReplicas(t *testing.T, burstReplicas, numReplicas int) {
client := client.NewOrDie(&client.Config{Host: "", Version: testapi.Version()})
fakePodControl := FakePodControl{}
manager := NewReplicationManager(client, burstReplicas)
manager.podStoreSynced = alwaysReady
manager.podControl = &fakePodControl
controllerSpec := newReplicationController(numReplicas)
manager.rcStore.Store.Add(controllerSpec)
expectedPods := 0
pods := newPodList(nil, numReplicas, api.PodPending, controllerSpec)
rcKey, err := controller.KeyFunc(controllerSpec)
if err != nil {
t.Errorf("Couldn't get key for object %+v: %v", controllerSpec, err)
}
// Size up the controller, then size it down, and confirm the expected create/delete pattern
for _, replicas := range []int{numReplicas, 0} {
controllerSpec.Spec.Replicas = replicas
manager.rcStore.Store.Add(controllerSpec)
for i := 0; i < numReplicas; i += burstReplicas {
manager.syncReplicationController(getKey(controllerSpec, t))
// The store accrues active pods. It's also used by the rc 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 rc manager above,
// which then puts the rc to sleep till all of them have been observed.
expectedPods = replicas - activePods
if expectedPods > burstReplicas {
expectedPods = burstReplicas
}
// This validates the rc manager sync actually created pods
validateSyncReplication(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(rcKey)
if !exists || err != nil {
t.Fatalf("Did not find expectations for rc.")
}
if add, _ := podExp.GetExpectations(); add != 1 {
t.Fatalf("Expectations are wrong %v", podExp)
}
} else {
expectedPods = (replicas - activePods) * -1
if expectedPods > burstReplicas {
expectedPods = burstReplicas
}
validateSyncReplication(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(rcKey)
if !exists || err != nil {
t.Fatalf("Did not find expectations for rc.")
}
if _, del := podExp.GetExpectations(); del != 1 {
t.Fatalf("Expectations are wrong %v", podExp)
}
}
// 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)
// Create/Delete the last pod
// The last add pod will decrease the expectation of the rc to 0,
// which will cause it to create/delete the remaining replicas upto 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 != controllerSpec.Spec.Replicas {
t.Fatalf("Unexpected number of active pods, expected %d, got %d", controllerSpec.Spec.Replicas, activePods)
}
// Replenish the pod list, since we cut it down sizing up
pods = newPodList(nil, replicas, api.PodRunning, controllerSpec)
}
}
