func (self *podAndContainerCollector) Collect(ch chan<- prometheus.Metric) {
	runningContainers, err := self.containerCache.RunningContainers()
	if err != nil {
		glog.Warning("Failed to get running container information while collecting metrics: %v", err)
		return
	}

	// Get a set of running pods.
	runningPods := make(map[types.UID]struct{})
	for _, cont := range runningContainers {
		_, uid, _, _, err := dockertools.ParseDockerName(cont.Names[0])
		if err != nil {
			continue
		}
		runningPods[uid] = struct{}{}
	}

	ch <- prometheus.MustNewConstMetric(
		runningPodCountDesc,
		prometheus.GaugeValue,
		float64(len(runningPods)))
	ch <- prometheus.MustNewConstMetric(
		runningContainerCountDesc,
		prometheus.GaugeValue,
		float64(len(runningContainers)))
}

// SyncPods synchronizes the configured list of pods (desired state) with the host current state.
func (kl *Kubelet) SyncPods(pods []api.BoundPod) error {
	glog.V(4).Infof("Desired: %#v", pods)
	var err error
	desiredContainers := make(map[podContainer]empty)
	desiredPods := make(map[string]empty)

	dockerContainers, err := dockertools.GetKubeletDockerContainers(kl.dockerClient, false)
	if err != nil {
		glog.Errorf("Error listing containers: %#v", dockerContainers)
		return err
	}

	// Check for any containers that need starting
	for ix := range pods {
		pod := &pods[ix]
		podFullName := GetPodFullName(pod)
		uuid := pod.UID
		desiredPods[uuid] = empty{}

		// Add all containers (including net) to the map.
		desiredContainers[podContainer{podFullName, uuid, networkContainerName}] = empty{}
		for _, cont := range pod.Spec.Containers {
			desiredContainers[podContainer{podFullName, uuid, cont.Name}] = empty{}
		}

		// Run the sync in an async manifest worker.
		kl.podWorkers.Run(podFullName, func() {
			err := kl.syncPod(pod, dockerContainers)
			if err != nil {
				glog.Errorf("Error syncing pod, skipping: %s", err)
			}
		})
	}

	// Kill any containers we don't need.
	for _, container := range dockerContainers {
		// Don't kill containers that are in the desired pods.
		podFullName, uuid, containerName, _ := dockertools.ParseDockerName(container.Names[0])
		if _, found := desiredPods[uuid]; found {
			// syncPod() will handle this one.
			continue
		}
		pc := podContainer{podFullName, uuid, containerName}
		if _, ok := desiredContainers[pc]; !ok {
			glog.V(1).Infof("Killing unwanted container %+v", pc)
			err = kl.killContainer(container)
			if err != nil {
				glog.Errorf("Error killing container %+v: %s", pc, err)
			}
		}
	}

	// Remove any orphaned volumes.
	kl.reconcileVolumes(pods)

	return err
}

// SyncPods synchronizes the configured list of pods (desired state) with the host current state.
func (kl *Kubelet) SyncPods(pods []Pod) error {
	glog.Infof("Desired [%s]: %+v", kl.hostname, pods)
	var err error
	desiredContainers := make(map[podContainer]empty)

	dockerContainers, err := dockertools.GetKubeletDockerContainers(kl.dockerClient)
	if err != nil {
		glog.Errorf("Error listing containers %#v", dockerContainers)
		return err
	}

	// Check for any containers that need starting
	for i := range pods {
		pod := &pods[i]
		podFullName := GetPodFullName(pod)
		uuid := pod.Manifest.UUID

		// Add all containers (including net) to the map.
		desiredContainers[podContainer{podFullName, uuid, networkContainerName}] = empty{}
		for _, cont := range pod.Manifest.Containers {
			desiredContainers[podContainer{podFullName, uuid, cont.Name}] = empty{}
		}

		// Run the sync in an async manifest worker.
		kl.podWorkers.Run(podFullName, func() {
			err := kl.syncPod(pod, dockerContainers)
			if err != nil {
				glog.Errorf("Error syncing pod: %v skipping.", err)
			}
		})
	}

	// Kill any containers we don't need
	existingContainers, err := dockertools.GetKubeletDockerContainers(kl.dockerClient)
	if err != nil {
		glog.Errorf("Error listing containers: %v", err)
		return err
	}
	for _, container := range existingContainers {
		// Don't kill containers that are in the desired pods.
		podFullName, uuid, containerName, _ := dockertools.ParseDockerName(container.Names[0])
		if _, ok := desiredContainers[podContainer{podFullName, uuid, containerName}]; !ok {
			err = kl.killContainer(container)
			if err != nil {
				glog.Errorf("Error killing container: %v", err)
			}
		}
	}

	// Remove any orphaned volumes.
	kl.reconcileVolumes(pods)

	return err
}

// Get all containers that are evictable. Evictable containers are: not running
// and created more than MinAge ago.
func (cgc *realContainerGC) evictableContainers() (containersByEvictUnit, []containerGCInfo, error) {
	containers, err := dockertools.GetKubeletDockerContainers(cgc.dockerClient, true)
	if err != nil {
		return containersByEvictUnit{}, []containerGCInfo{}, err
	}

	unidentifiedContainers := make([]containerGCInfo, 0)
	evictUnits := make(containersByEvictUnit)
	newestGCTime := time.Now().Add(-cgc.policy.MinAge)
	for _, container := range containers {
		// Prune out running containers.
		data, err := cgc.dockerClient.InspectContainer(container.ID)
		if err != nil {
			// Container may have been removed already, skip.
			continue
		} else if data.State.Running {
			continue
		} else if newestGCTime.Before(data.Created) {
			continue
		}

		containerInfo := containerGCInfo{
			id:         container.ID,
			name:       container.Names[0],
			createTime: data.Created,
		}

		containerName, _, err := dockertools.ParseDockerName(container.Names[0])

		if err != nil {
			unidentifiedContainers = append(unidentifiedContainers, containerInfo)
		} else {
			key := evictUnit{
				uid:  containerName.PodUID,
				name: containerName.ContainerName,
			}
			containerInfo.podNameWithNamespace = containerName.PodFullName
			containerInfo.containerName = containerName.ContainerName
			evictUnits[key] = append(evictUnits[key], containerInfo)
		}
	}

	// Sort the containers by age.
	for uid := range evictUnits {
		sort.Sort(byCreated(evictUnits[uid]))
	}

	return evictUnits, unidentifiedContainers, nil
}

func (kl *Kubelet) killContainerByID(ID, name string) error {
	glog.Infof("Killing: %s", ID)
	err := kl.dockerClient.StopContainer(ID, 10)
	if len(name) == 0 {
		return err
	}
	podFullName, uuid, containerName, _ := dockertools.ParseDockerName(name)
	kl.LogEvent(&api.Event{
		Event: "STOP",
		Manifest: &api.ContainerManifest{
			//TODO: This should be reported using either the apiserver schema or the kubelet schema
			ID:   podFullName,
			UUID: uuid,
		},
		Container: &api.Container{
			Name: containerName,
		},
	})

	return err
}

// TODO: Also enforce a maximum total number of containers.
func (kl *Kubelet) GarbageCollectContainers() error {
	if kl.maxContainerCount == 0 {
		return nil
	}
	containers, err := dockertools.GetKubeletDockerContainers(kl.dockerClient, true)
	if err != nil {
		return err
	}
	uuidToIDMap := map[string][]string{}
	for _, container := range containers {
		_, uuid, name, _ := dockertools.ParseDockerName(container.ID)
		uuidName := uuid + "." + name
		uuidToIDMap[uuidName] = append(uuidToIDMap[uuidName], container.ID)
	}
	for _, list := range uuidToIDMap {
		if len(list) <= kl.maxContainerCount {
			continue
		}
		if err := kl.purgeOldest(list); err != nil {
			return err
		}
	}
	return nil
}

//.........这里部分代码省略.........
					containersToKeep[containerID] = empty{}
					continue
				}
				if healthy == health.Healthy {
					containersToKeep[containerID] = empty{}
					continue
				}
				glog.V(1).Infof("pod %q container %q is unhealthy. Container will be killed and re-created.", podFullName, container.Name, healthy)
			} else {
				glog.V(1).Infof("pod %q container %q hash changed (%d vs %d). Container will be killed and re-created.", podFullName, container.Name, hash, expectedHash)
			}
			if err := kl.killContainer(dockerContainer); err != nil {
				glog.V(1).Infof("Failed to kill container %q: %v", dockerContainer.ID, err)
				continue
			}
			killedContainers[containerID] = empty{}

			// Also kill associated network container
			if netContainer, found, _ := dockerContainers.FindPodContainer(podFullName, uuid, networkContainerName); found {
				if err := kl.killContainer(netContainer); err != nil {
					glog.V(1).Infof("Failed to kill network container %q: %v", netContainer.ID, err)
					continue
				}
			}
		}

		// Check RestartPolicy for container
		recentContainers, err := dockertools.GetRecentDockerContainersWithNameAndUUID(kl.dockerClient, podFullName, uuid, container.Name)
		if err != nil {
			glog.Errorf("Error listing recent containers with name and uuid:%s--%s--%s", podFullName, uuid, container.Name)
			// TODO(dawnchen): error handling here?
		}

		if len(recentContainers) > 0 && pod.Spec.RestartPolicy.Always == nil {
			if pod.Spec.RestartPolicy.Never != nil {
				glog.V(3).Infof("Already ran container with name %s--%s--%s, do nothing",
					podFullName, uuid, container.Name)
				continue
			}
			if pod.Spec.RestartPolicy.OnFailure != nil {
				// Check the exit code of last run
				if recentContainers[0].State.ExitCode == 0 {
					glog.V(3).Infof("Already successfully ran container with name %s--%s--%s, do nothing",
						podFullName, uuid, container.Name)
					continue
				}
			}
		}

		glog.V(3).Infof("Container with name %s--%s--%s doesn't exist, creating %#v", podFullName, uuid, container.Name, container)
		ref, err := containerRef(pod, &container)
		if err != nil {
			glog.Errorf("Couldn't make a ref to pod %v, container %v: '%v'", pod.Name, container.Name, err)
		}
		if !api.IsPullNever(container.ImagePullPolicy) {
			present, err := kl.dockerPuller.IsImagePresent(container.Image)
			latest := dockertools.RequireLatestImage(container.Image)
			if err != nil {
				if ref != nil {
					record.Eventf(ref, "failed", "failed", "Failed to inspect image %q", container.Image)
				}
				glog.Errorf("Failed to inspect image %q: %v; skipping pod %q container %q", container.Image, err, podFullName, container.Name)
				continue
			}
			if api.IsPullAlways(container.ImagePullPolicy) ||
				(api.IsPullIfNotPresent(container.ImagePullPolicy) && (!present || latest)) {
				if err := kl.pullImage(container.Image, ref); err != nil {
					continue
				}
			}
		}
		// TODO(dawnchen): Check RestartPolicy.DelaySeconds before restart a container
		containerID, err := kl.runContainer(pod, &container, podVolumes, "container:"+string(netID))
		if err != nil {
			// TODO(bburns) : Perhaps blacklist a container after N failures?
			glog.Errorf("Error running pod %q container %q: %v", podFullName, container.Name, err)
			continue
		}
		containersToKeep[containerID] = empty{}
	}

	// Kill any containers in this pod which were not identified above (guards against duplicates).
	for id, container := range dockerContainers {
		curPodFullName, curUUID, _, _ := dockertools.ParseDockerName(container.Names[0])
		if curPodFullName == podFullName && curUUID == uuid {
			// Don't kill containers we want to keep or those we already killed.
			_, keep := containersToKeep[id]
			_, killed := killedContainers[id]
			if !keep && !killed {
				glog.V(1).Infof("Killing unwanted container in pod %q: %+v", curUUID, container)
				err = kl.killContainer(container)
				if err != nil {
					glog.Errorf("Error killing container: %v", err)
				}
			}
		}
	}

	return nil
}

//.........这里部分代码省略.........
		return err
	}

	podState := api.PodState{Manifest: api.ContainerManifest{UUID: uuid}}
	info, err := kl.GetPodInfo(podFullName, uuid)
	if err != nil {
		glog.Errorf("Unable to get pod with name %s and uuid %s info, health checks may be invalid.",
			podFullName, uuid)
	}
	netInfo, found := info[networkContainerName]
	if found && netInfo.NetworkSettings != nil {
		podState.PodIP = netInfo.NetworkSettings.IPAddress
	}

	for _, container := range pod.Manifest.Containers {
		expectedHash := dockertools.HashContainer(&container)
		if dockerContainer, found, hash := dockerContainers.FindPodContainer(podFullName, uuid, container.Name); found {
			containerID := dockertools.DockerID(dockerContainer.ID)
			glog.V(1).Infof("pod %s container %s exists as %v", podFullName, container.Name, containerID)

			// look for changes in the container.
			if hash == 0 || hash == expectedHash {
				// TODO: This should probably be separated out into a separate goroutine.
				healthy, err := kl.healthy(podFullName, podState, container, dockerContainer)
				if err != nil {
					glog.V(1).Infof("health check errored: %v", err)
					containersToKeep[containerID] = empty{}
					continue
				}
				if healthy == health.Healthy {
					containersToKeep[containerID] = empty{}
					continue
				}
				glog.V(1).Infof("pod %s container %s is unhealthy.", podFullName, container.Name, healthy)
			} else {
				glog.V(1).Infof("container hash changed %d vs %d.", hash, expectedHash)
			}
			if err := kl.killContainer(dockerContainer); err != nil {
				glog.V(1).Infof("Failed to kill container %s: %v", dockerContainer.ID, err)
				continue
			}
			killedContainers[containerID] = empty{}
		}

		// Check RestartPolicy for container
		recentContainers, err := dockertools.GetRecentDockerContainersWithNameAndUUID(kl.dockerClient, podFullName, uuid, container.Name)
		if err != nil {
			glog.Errorf("Error listing recent containers with name and uuid:%s--%s--%s", podFullName, uuid, container.Name)
			// TODO(dawnchen): error handling here?
		}

		if len(recentContainers) > 0 && pod.Manifest.RestartPolicy.Always == nil {
			if pod.Manifest.RestartPolicy.Never != nil {
				glog.Infof("Already ran container with name %s--%s--%s, do nothing",
					podFullName, uuid, container.Name)
				continue
			}
			if pod.Manifest.RestartPolicy.OnFailure != nil {
				// Check the exit code of last run
				if recentContainers[0].State.ExitCode == 0 {
					glog.Infof("Already successfully ran container with name %s--%s--%s, do nothing",
						podFullName, uuid, container.Name)
					continue
				}
			}
		}

		glog.Infof("Container with name %s--%s--%s doesn't exist, creating %#v", podFullName, uuid, container.Name, container)
		if err := kl.dockerPuller.Pull(container.Image); err != nil {
			glog.Errorf("Failed to pull image %s: %v skipping pod %s container %s.", container.Image, err, podFullName, container.Name)
			continue
		}
		// TODO(dawnchen): Check RestartPolicy.DelaySeconds before restart a container
		containerID, err := kl.runContainer(pod, &container, podVolumes, "container:"+string(netID))
		if err != nil {
			// TODO(bburns) : Perhaps blacklist a container after N failures?
			glog.Errorf("Error running pod %s container %s: %v", podFullName, container.Name, err)
			continue
		}
		containersToKeep[containerID] = empty{}
	}

	// Kill any containers in this pod which were not identified above (guards against duplicates).
	for id, container := range dockerContainers {
		curPodFullName, curUUID, _, _ := dockertools.ParseDockerName(container.Names[0])
		if curPodFullName == podFullName && curUUID == uuid {
			// Don't kill containers we want to keep or those we already killed.
			_, keep := containersToKeep[id]
			_, killed := killedContainers[id]
			if !keep && !killed {
				err = kl.killContainer(container)
				if err != nil {
					glog.Errorf("Error killing container: %v", err)
				}
			}
		}
	}

	return nil
}

// SyncPods synchronizes the configured list of pods (desired state) with the host current state.
func (kl *Kubelet) SyncPods(pods []api.BoundPod) error {
	glog.V(4).Infof("Desired: %#v", pods)
	var err error
	desiredContainers := make(map[podContainer]empty)
	desiredPods := make(map[types.UID]empty)

	dockerContainers, err := dockertools.GetKubeletDockerContainers(kl.dockerClient, false)
	if err != nil {
		glog.Errorf("Error listing containers: %#v", dockerContainers)
		return err
	}

	// Check for any containers that need starting
	for ix := range pods {
		pod := &pods[ix]
		podFullName := GetPodFullName(pod)
		uid := pod.UID
		desiredPods[uid] = empty{}

		// Add all containers (including net) to the map.
		desiredContainers[podContainer{podFullName, uid, networkContainerName}] = empty{}
		for _, cont := range pod.Spec.Containers {
			desiredContainers[podContainer{podFullName, uid, cont.Name}] = empty{}
		}

		// Run the sync in an async manifest worker.
		kl.podWorkers.Run(podFullName, func() {
			if err := kl.syncPod(pod, dockerContainers); err != nil {
				glog.Errorf("Error syncing pod, skipping: %v", err)
				record.Eventf(pod, "failedSync", "Error syncing pod, skipping: %v", err)
			}
		})
	}
	// Kill any containers we don't need.
	for _, container := range dockerContainers {
		// Don't kill containers that are in the desired pods.
		podFullName, uid, containerName, _ := dockertools.ParseDockerName(container.Names[0])
		if _, found := desiredPods[uid]; found {
			// syncPod() will handle this one.
			continue
		}
		_, _, podAnnotations := ParsePodFullName(podFullName)
		if source := podAnnotations[ConfigSourceAnnotationKey]; !kl.sourceReady(source) {
			// If the source for this container is not ready, skip deletion, so that we don't accidentally
			// delete containers for sources that haven't reported yet.
			glog.V(4).Infof("Skipping delete of container (%q), source (%s) aren't ready yet.", podFullName, source)
			continue
		}
		pc := podContainer{podFullName, uid, containerName}
		if _, ok := desiredContainers[pc]; !ok {
			glog.V(1).Infof("Killing unwanted container %+v", pc)
			err = kl.killContainer(container)
			if err != nil {
				glog.Errorf("Error killing container %+v: %v", pc, err)
			}
		}
	}

	// Remove any orphaned pods.
	err = kl.cleanupOrphanedPods(pods)
	if err != nil {
		return err
	}

	// Remove any orphaned volumes.
	err = kl.cleanupOrphanedVolumes(pods)
	if err != nil {
		return err
	}

	return err
}