Fix container restarts caused by kubelet restarts

There has been a recent regression causing kubelet to assume no containers are
running for the pod if kubelet has not seen the pod before. This would cause
all containers to be restarted after kubelet gets restarted. This change fixes
the bug.

pkg/kubelet/kubelet.go

@@ -1709,30 +1709,28 @@ func (kl *Kubelet) syncPod(pod *api.Pod, mirrorPod *api.Pod, runningPod kubecont
 	var apiPodStatus api.PodStatus
 	var podStatus *kubecontainer.PodStatus
 
+	// Always generate the kubecontainer.PodStatus to know whether there are
+	// running containers associated with the pod.
+	podStatusPtr, apiPodStatusPtr, err := kl.containerRuntime.GetPodStatusAndAPIPodStatus(pod)
+	if err != nil {
+		glog.Errorf("Unable to get status for pod %q: %v", format.Pod(pod), err)
+		return err
+	}
+	apiPodStatus = *apiPodStatusPtr
+	podStatus = podStatusPtr
+
 	if updateType == kubetypes.SyncPodCreate {
 		// This is the first time we are syncing the pod. Record the latency
 		// since kubelet first saw the pod if firstSeenTime is set.
 		if !firstSeenTime.IsZero() {
 			metrics.PodWorkerStartLatency.Observe(metrics.SinceInMicroseconds(firstSeenTime))
 		}
-
+		// kubelet may have just been restarted. Re-use the last known
+		// apiPodStatus.
 		apiPodStatus = pod.Status
 		apiPodStatus.StartTime = &unversioned.Time{Time: start}
 		kl.statusManager.SetPodStatus(pod, apiPodStatus)
-		podStatus = &kubecontainer.PodStatus{
-			ID:        pod.UID,
-			Name:      pod.Name,
-			Namespace: pod.Namespace,
-		}
-		glog.V(3).Infof("Not generating pod status for new pod %q", format.Pod(pod))
-	} else {
-		podStatusPtr, apiPodStatusPtr, err := kl.containerRuntime.GetPodStatusAndAPIPodStatus(pod)
-		if err != nil {
-			glog.Errorf("Unable to get status for pod %q: %v", format.Pod(pod), err)
-			return err
-		}
-		apiPodStatus = *apiPodStatusPtr
-		podStatus = podStatusPtr
+		glog.V(3).Infof("Reusing api pod status for new pod %q", format.Pod(pod))
 	}
 
 	pullSecrets, err := kl.getPullSecretsForPod(pod)