Fix "Kubelet doesn't kill old pods when BoundPods is empty" issue

pkg/kubelet/config/etcd.go

@@ -59,7 +59,16 @@ func NewSourceEtcd(key string, client tools.EtcdClient, updates chan<- interface
 }
 
 func (s *sourceEtcd) run() {
-	watching := s.helper.Watch(s.key, 0)
+	boundPods := api.BoundPods{}
+	err := s.helper.ExtractToList(s.key, &boundPods)
+	if err != nil {
+		glog.Errorf("etcd failed to retrieve the value for the key %q. Error: %v", s.key, err)
+		return
+	}
+	// Push update. Maybe an empty PodList to allow EtcdSource to be marked as seen
+	s.updates <- kubelet.PodUpdate{boundPods.Items, kubelet.SET, kubelet.EtcdSource}
+	index, _ := s.helper.ResourceVersioner.ResourceVersion(&boundPods)
+	watching := s.helper.Watch(s.key, index)
 	for {
 		select {
 		case event, ok := <-watching.ResultChan():
@@ -87,6 +96,9 @@ func (s *sourceEtcd) run() {
 // It returns a list of containers, or an error if one occurs.
 func eventToPods(ev watch.Event) ([]api.BoundPod, error) {
 	pods := []api.BoundPod{}
+	if ev.Object == nil {
+		return pods, nil
+	}
 	boundPods, ok := ev.Object.(*api.BoundPods)
 	if !ok {
 		return pods, errors.New("unable to parse response as BoundPods")

pkg/kubelet/config/etcd_test.go

@@ -33,7 +33,7 @@ func TestEventToPods(t *testing.T) {
 		{
 			input: watch.Event{Object: nil},
 			pods:  []api.BoundPod{},
-			fail:  true,
+			fail:  false,
 		},
 		{
 			input: watch.Event{Object: &api.BoundPods{}},

pkg/kubelet/config/file.go

@@ -64,6 +64,8 @@ func (s *sourceFile) extractFromPath() error {
 		if !os.IsNotExist(err) {
 			return err
 		}
+		// Emit an update with an empty PodList to allow FileSource to be marked as seen
+		s.updates <- kubelet.PodUpdate{[]api.BoundPod{}, kubelet.SET, kubelet.FileSource}
 		return fmt.Errorf("path does not exist, ignoring")
 	}
 

pkg/kubelet/config/file_test.go

@@ -92,8 +92,14 @@ func TestUpdateOnNonExistentFile(t *testing.T) {
 	NewSourceFile("random_non_existent_path", time.Millisecond, ch)
 	select {
 	case got := <-ch:
-		t.Errorf("Expected no update, Got %#v", got)
+		update := got.(kubelet.PodUpdate)
+		expected := CreatePodUpdate(kubelet.SET, kubelet.FileSource)
+		if !api.Semantic.DeepEqual(expected, update) {
+			t.Fatalf("Expected %#v, Got %#v", expected, update)
+		}
+
 	case <-time.After(2 * time.Millisecond):
+		t.Errorf("Expected update, timeout instead")
 	}
 }
 

pkg/kubelet/config/http.go

@@ -69,6 +69,8 @@ func (s *sourceURL) extractFromURL() error {
 		return fmt.Errorf("%v: %v", s.url, resp.Status)
 	}
 	if len(data) == 0 {
+		// Emit an update with an empty PodList to allow HTTPSource to be marked as seen
+		s.updates <- kubelet.PodUpdate{[]api.BoundPod{}, kubelet.SET, kubelet.HTTPSource}
 		return fmt.Errorf("zero-length data received from %v", s.url)
 	}
 	// Short circuit if the manifest has not changed since the last time it was read.

pkg/kubelet/kubelet.go

@@ -1118,9 +1118,6 @@ func (kl *Kubelet) syncLoop(updates <-chan PodUpdate, handler SyncHandler) {
 			}
 		case <-time.After(kl.resyncInterval):
 			glog.V(4).Infof("Periodic sync")
-			if kl.pods == nil {
-				continue
-			}
 		}
 
 		err := handler.SyncPods(kl.pods)