Merge pull request #12560 from yujuhong/sync_pods

kubelet: refactor SyncPods for better readability

pkg/kubelet/kubelet.go

@@ -89,7 +89,6 @@ var (
 
 // SyncHandler is an interface implemented by Kubelet, for testability
 type SyncHandler interface {
-
 	// Syncs current state to match the specified pods. SyncPodType specified what
 	// type of sync is occurring per pod. StartTime specifies the time at which
 	// syncing began (for use in monitoring).
@@ -1422,42 +1421,56 @@ func (kl *Kubelet) SyncPods(allPods []*api.Pod, podSyncTypes map[types.UID]SyncP
 		metrics.SyncPodsLatency.Observe(metrics.SinceInMicroseconds(start))
 	}()
 
-	// Remove obsolete entries in podStatus where the pod is no longer considered bound to this node.
+	kl.removeOrphanedPodStatuses(allPods)
+	// Handles pod admission.
+	pods := kl.admitPods(allPods, podSyncTypes)
+	glog.V(4).Infof("Desired pods: %s", kubeletUtil.FormatPodNames(pods))
+	// Send updates to pod workers.
+	kl.dispatchWork(pods, podSyncTypes, mirrorPods, start)
+	// Clean up unwanted/orphaned resources.
+	if err := kl.cleanupPods(allPods, pods); err != nil {
+		return err
+	}
+	return nil
+}
+
+// removeOrphanedPodStatuses removes obsolete entries in podStatus where
+// the pod is no longer considered bound to this node.
+// TODO(yujuhong): consider using pod UID as they key in the status manager
+// to avoid returning the wrong status.
+func (kl *Kubelet) removeOrphanedPodStatuses(pods []*api.Pod) {
 	podFullNames := make(map[string]bool)
-	for _, pod := range allPods {
+	for _, pod := range pods {
 		podFullNames[kubecontainer.GetPodFullName(pod)] = true
 	}
 	kl.statusManager.RemoveOrphanedStatuses(podFullNames)
+}
 
-	// Handles pod admission.
-	pods := kl.admitPods(allPods, podSyncTypes)
-
-	glog.V(4).Infof("Desired pods: %s", kubeletUtil.FormatPodNames(pods))
-	var err error
-	desiredPods := make(map[types.UID]empty)
-
-	runningPods, err := kl.runtimeCache.GetPods()
-	if err != nil {
-		glog.Errorf("Error listing containers: %#v", err)
-		return err
-	}
-
+// dispatchWork dispatches pod updates to workers.
+func (kl *Kubelet) dispatchWork(pods []*api.Pod, podSyncTypes map[types.UID]SyncPodType,
+	mirrorPods map[string]*api.Pod, start time.Time) {
 	// Check for any containers that need starting
 	for _, pod := range pods {
 		podFullName := kubecontainer.GetPodFullName(pod)
-		uid := pod.UID
-		desiredPods[uid] = empty{}
-
 		// Run the sync in an async manifest worker.
 		kl.podWorkers.UpdatePod(pod, mirrorPods[podFullName], func() {
 			metrics.PodWorkerLatency.WithLabelValues(podSyncTypes[pod.UID].String()).Observe(metrics.SinceInMicroseconds(start))
 		})
-
 		// Note the number of containers for new pods.
 		if val, ok := podSyncTypes[pod.UID]; ok && (val == SyncPodCreate) {
 			metrics.ContainersPerPodCount.Observe(float64(len(pod.Spec.Containers)))
 		}
 	}
+}
+
+// cleanupPods performs a series of cleanup work, including terminating pod
+// workers, killing unwanted pods, and removing orphaned volumes/pod
+// directories.
+func (kl *Kubelet) cleanupPods(allPods []*api.Pod, admittedPods []*api.Pod) error {
+	desiredPods := make(map[types.UID]empty)
+	for _, pod := range admittedPods {
+		desiredPods[pod.UID] = empty{}
+	}
 	// Stop the workers for no-longer existing pods.
 	kl.podWorkers.ForgetNonExistingPodWorkers(desiredPods)
 
@@ -1468,6 +1481,12 @@ func (kl *Kubelet) SyncPods(allPods []*api.Pod, podSyncTypes map[types.UID]SyncP
 		return nil
 	}
 
+	runningPods, err := kl.runtimeCache.GetPods()
+	if err != nil {
+		glog.Errorf("Error listing containers: %#v", err)
+		return err
+	}
+
 	// Kill containers associated with unwanted pods.
 	err = kl.killUnwantedPods(desiredPods, runningPods)
 	if err != nil {