Kubelet should garbage collect dead pods

The sync loop should check for terminated pods that are no longer
running and clear them. The status loop should never write status
if the pod UID changes. Mirror pods should be deleted immediately
rather than gracefully.

pkg/kubelet/kubelet.go

@@ -1367,6 +1367,32 @@ func (kl *Kubelet) cleanupOrphanedVolumes(pods []*api.Pod, runningPods []*kubeco
 	return nil
 }
 
+// Delete any pods that are no longer running and are marked for deletion.
+func (kl *Kubelet) cleanupTerminatedPods(pods []*api.Pod, runningPods []*kubecontainer.Pod) error {
+	var terminating []*api.Pod
+	for _, pod := range pods {
+		if pod.DeletionTimestamp != nil {
+			found := false
+			for _, runningPod := range runningPods {
+				if runningPod.ID == pod.UID {
+					found = true
+					break
+				}
+			}
+			if found {
+				podFullName := kubecontainer.GetPodFullName(pod)
+				glog.V(5).Infof("Keeping terminated pod %q and uid %q, still running", podFullName, pod.UID)
+				continue
+			}
+			terminating = append(terminating, pod)
+		}
+	}
+	if !kl.statusManager.TerminatePods(terminating) {
+		return errors.New("not all pods were successfully terminated")
+	}
+	return nil
+}
+
 // pastActiveDeadline returns true if the pod has been active for more than
 // ActiveDeadlineSeconds.
 func (kl *Kubelet) pastActiveDeadline(pod *api.Pod) bool {
@@ -1529,6 +1555,10 @@ func (kl *Kubelet) cleanupPods(allPods []*api.Pod, admittedPods []*api.Pod) erro
 	// Remove any orphaned mirror pods.
 	kl.podManager.DeleteOrphanedMirrorPods()
 
+	if err := kl.cleanupTerminatedPods(allPods, runningPods); err != nil {
+		glog.Errorf("Failed to cleanup terminated pods: %v", err)
+	}
+
 	return err
 }