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syncLoopIteration

kubelet源码分析(四)之 syncLoopIteration

以下代码分析基于 kubernetes v1.12.0 版本。
本文主要分析kubelet中syncLoopIteration部分。syncLoopIteration通过几种channel来对不同类型的事件进行监听并做增删改查的处理。

1. syncLoop

syncLoop是处理变更的循环。 它监听来自三种channel(file,apiserver和http)的更改。 对于看到的任何新更改,将针对所需状态和运行状态运行同步。 如果没有看到配置的变化,将在每个同步频率秒同步最后已知的所需状态。
此部分代码位于pkg/kubelet/kubelet.go
// syncLoop is the main loop for processing changes. It watches for changes from
// three channels (file, apiserver, and http) and creates a union of them. For
// any new change seen, will run a sync against desired state and running state. If
// no changes are seen to the configuration, will synchronize the last known desired
// state every sync-frequency seconds. Never returns.
func (kl *Kubelet) syncLoop(updates <-chan kubetypes.PodUpdate, handler SyncHandler) {
glog.Info("Starting kubelet main sync loop.")
// The resyncTicker wakes up kubelet to checks if there are any pod workers
// that need to be sync'd. A one-second period is sufficient because the
// sync interval is defaulted to 10s.
syncTicker := time.NewTicker(time.Second)
defer syncTicker.Stop()
housekeepingTicker := time.NewTicker(housekeepingPeriod)
defer housekeepingTicker.Stop()
plegCh := kl.pleg.Watch()
const (
base = 100 * time.Millisecond
max = 5 * time.Second
factor = 2
)
duration := base
for {
if rs := kl.runtimeState.runtimeErrors(); len(rs) != 0 {
glog.Infof("skipping pod synchronization - %v", rs)
// exponential backoff
time.Sleep(duration)
duration = time.Duration(math.Min(float64(max), factor*float64(duration)))
continue
}
// reset backoff if we have a success
duration = base
kl.syncLoopMonitor.Store(kl.clock.Now())
if !kl.syncLoopIteration(updates, handler, syncTicker.C, housekeepingTicker.C, plegCh) {
break
}
kl.syncLoopMonitor.Store(kl.clock.Now())
}
}
其中调用了syncLoopIteration的函数来执行更具体的监控pod变化的循环。
syncLoopIteration主要通过几种channel来对不同类型的事件进行监听并处理。其中包括:configChplegChsyncChhouseKeepingChlivenessManager.Updates()
syncLoopIteration实际执行了pod的操作,此部分设置了几种不同的channel:
  • configCh:将配置更改的pod分派给事件类型的相应处理程序回调。
  • plegCh:更新runtime缓存,同步pod。
  • syncCh:同步所有等待同步的pod。
  • houseKeepingCh:触发清理pod。
  • livenessManager.Updates():对失败的pod或者liveness检查失败的pod进行sync操作。
syncLoopIteration部分代码位于pkg/kubelet/kubelet.go

2.1. configCh

configCh将配置更改的pod分派给事件类型的相应处理程序回调,该部分主要通过SyncHandler对pod的不同事件进行增删改查等操作。
func (kl *Kubelet) syncLoopIteration(configCh <-chan kubetypes.PodUpdate, handler SyncHandler,
syncCh <-chan time.Time, housekeepingCh <-chan time.Time, plegCh <-chan *pleg.PodLifecycleEvent) bool {
select {
case u, open := <-configCh:
// Update from a config source; dispatch it to the right handler
// callback.
if !open {
glog.Errorf("Update channel is closed. Exiting the sync loop.")
return false
}
switch u.Op {
case kubetypes.ADD:
glog.V(2).Infof("SyncLoop (ADD, %q): %q", u.Source, format.Pods(u.Pods))
// After restarting, kubelet will get all existing pods through
// ADD as if they are new pods. These pods will then go through the
// admission process and *may* be rejected. This can be resolved
// once we have checkpointing.
handler.HandlePodAdditions(u.Pods)
case kubetypes.UPDATE:
glog.V(2).Infof("SyncLoop (UPDATE, %q): %q", u.Source, format.PodsWithDeletionTimestamps(u.Pods))
handler.HandlePodUpdates(u.Pods)
case kubetypes.REMOVE:
glog.V(2).Infof("SyncLoop (REMOVE, %q): %q", u.Source, format.Pods(u.Pods))
handler.HandlePodRemoves(u.Pods)
case kubetypes.RECONCILE:
glog.V(4).Infof("SyncLoop (RECONCILE, %q): %q", u.Source, format.Pods(u.Pods))
handler.HandlePodReconcile(u.Pods)
case kubetypes.DELETE:
glog.V(2).Infof("SyncLoop (DELETE, %q): %q", u.Source, format.Pods(u.Pods))
// DELETE is treated as a UPDATE because of graceful deletion.
handler.HandlePodUpdates(u.Pods)
case kubetypes.RESTORE:
glog.V(2).Infof("SyncLoop (RESTORE, %q): %q", u.Source, format.Pods(u.Pods))
// These are pods restored from the checkpoint. Treat them as new
// pods.
handler.HandlePodAdditions(u.Pods)
case kubetypes.SET:
// TODO: Do we want to support this?
glog.Errorf("Kubelet does not support snapshot update")
}
...
}
可以看出syncLoopIteration根据podUpdate的值来执行不同的pod操作,具体如下:
  • ADD:HandlePodAdditions
  • UPDATE:HandlePodUpdates
  • REMOVE:HandlePodRemoves
  • RECONCILE:HandlePodReconcile
  • DELETE:HandlePodUpdates
  • RESTORE:HandlePodAdditions
  • podsToSync:HandlePodSyncs
其中执行pod的handler操作的是SyncHandler,该类型是一个接口,实现体为kubelet本身,具体见后续分析。

2.2. plegCh

plegCh:更新runtime缓存,同步pod。此处调用了HandlePodSyncs的函数。
case e := <-plegCh:
if isSyncPodWorthy(e) {
// PLEG event for a pod; sync it.
if pod, ok := kl.podManager.GetPodByUID(e.ID); ok {
glog.V(2).Infof("SyncLoop (PLEG): %q, event: %#v", format.Pod(pod), e)
handler.HandlePodSyncs([]*v1.Pod{pod})
} else {
// If the pod no longer exists, ignore the event.
glog.V(4).Infof("SyncLoop (PLEG): ignore irrelevant event: %#v", e)
}
}
if e.Type == pleg.ContainerDied {
if containerID, ok := e.Data.(string); ok {
kl.cleanUpContainersInPod(e.ID, containerID)
}
}

2.3. syncCh

syncCh:同步所有等待同步的pod。此处调用了HandlePodSyncs的函数。
case <-syncCh:
// Sync pods waiting for sync
podsToSync := kl.getPodsToSync()
if len(podsToSync) == 0 {
break
}
glog.V(4).Infof("SyncLoop (SYNC): %d pods; %s", len(podsToSync), format.Pods(podsToSync))
handler.HandlePodSyncs(podsToSync)

2.4. livenessManager.Update

livenessManager.Updates():对失败的pod或者liveness检查失败的pod进行sync操作。此处调用了HandlePodSyncs的函数。
case update := <-kl.livenessManager.Updates():
if update.Result == proberesults.Failure {
// The liveness manager detected a failure; sync the pod.
// We should not use the pod from livenessManager, because it is never updated after
// initialization.
pod, ok := kl.podManager.GetPodByUID(update.PodUID)
if !ok {
// If the pod no longer exists, ignore the update.
glog.V(4).Infof("SyncLoop (container unhealthy): ignore irrelevant update: %#v", update)
break
}
glog.V(1).Infof("SyncLoop (container unhealthy): %q", format.Pod(pod))
handler.HandlePodSyncs([]*v1.Pod{pod})
}

2.5. housekeepingCh

houseKeepingCh:触发清理pod。此处调用了HandlePodCleanups的函数。
case <-housekeepingCh:
if !kl.sourcesReady.AllReady() {
// If the sources aren't ready or volume manager has not yet synced the states,
// skip housekeeping, as we may accidentally delete pods from unready sources.
glog.V(4).Infof("SyncLoop (housekeeping, skipped): sources aren't ready yet.")
} else {
glog.V(4).Infof("SyncLoop (housekeeping)")
if err := handler.HandlePodCleanups(); err != nil {
glog.Errorf("Failed cleaning pods: %v", err)
}
}
SyncHandler是一个定义Pod的不同Handler的接口,具体是实现者是kubelet,该接口的方法主要在syncLoopIteration中调用,接口定义如下:
// SyncHandler is an interface implemented by Kubelet, for testability
type SyncHandler interface {
HandlePodAdditions(pods []*v1.Pod)
HandlePodUpdates(pods []*v1.Pod)
HandlePodRemoves(pods []*v1.Pod)
HandlePodReconcile(pods []*v1.Pod)
HandlePodSyncs(pods []*v1.Pod)
HandlePodCleanups() error
}
SyncHandler部分代码位于pkg/kubelet/kubelet.go
HandlePodAdditions先根据pod创建时间对pod进行排序,然后遍历pod列表,来执行pod的相关操作。
// HandlePodAdditions is the callback in SyncHandler for pods being added from
// a config source.
func (kl *Kubelet) HandlePodAdditions(pods []*v1.Pod) {
start := kl.clock.Now()
sort.Sort(sliceutils.PodsByCreationTime(pods))
for _, pod := range pods {
...
}
}
将pod添加到pod manager中。
for _, pod := range pods {
// Responsible for checking limits in resolv.conf
if kl.dnsConfigurer != nil && kl.dnsConfigurer.ResolverConfig != "" {
kl.dnsConfigurer.CheckLimitsForResolvConf()
}
existingPods := kl.podManager.GetPods()
// Always add the pod to the pod manager. Kubelet relies on the pod
// manager as the source of truth for the desired state. If a pod does
// not exist in the pod manager, it means that it has been deleted in
// the apiserver and no action (other than cleanup) is required.
kl.podManager.AddPod(pod)
...
}
如果是mirror pod,则对mirror pod进行处理。
if kubepod.IsMirrorPod(pod) {
kl.handleMirrorPod(pod, start)
continue
}
如果当前pod的状态不是Terminated状态,则判断是否接受该pod,如果不接受则将pod状态改为Failed
if !kl.podIsTerminated(pod) {
// Only go through the admission process if the pod is not
// terminated.
// We failed pods that we rejected, so activePods include all admitted
// pods that are alive.
activePods := kl.filterOutTerminatedPods(existingPods)
// Check if we can admit the pod; if not, reject it.
if ok, reason, message := kl.canAdmitPod(activePods, pod); !ok {
kl.rejectPod(pod, reason, message)
continue
}
}
执行dispatchWork函数,该函数是syncHandler中调用到的核心函数,该函数在pod worker中启动一个异步循环,来分派pod的相关操作。该函数的具体操作待后续分析。
mirrorPod, _ := kl.podManager.GetMirrorPodByPod(pod)
kl.dispatchWork(pod, kubetypes.SyncPodCreate, mirrorPod, start)
最后加pod添加到probe manager中。
kl.probeManager.AddPod(pod)
HandlePodUpdates同样遍历pod列表,执行相应的操作。
// HandlePodUpdates is the callback in the SyncHandler interface for pods
// being updated from a config source.
func (kl *Kubelet) HandlePodUpdates(pods []*v1.Pod) {
start := kl.clock.Now()
for _, pod := range pods {
...
}
}
将pod更新到pod manager中。
for _, pod := range pods {
// Responsible for checking limits in resolv.conf
if kl.dnsConfigurer != nil && kl.dnsConfigurer.ResolverConfig != "" {
kl.dnsConfigurer.CheckLimitsForResolvConf()
}
kl.podManager.UpdatePod(pod)
...
}
如果是mirror pod,则对mirror pod进行处理。
if kubepod.IsMirrorPod(pod) {
kl.handleMirrorPod(pod, start)
continue
}
执行dispatchWork函数。
// TODO: Evaluate if we need to validate and reject updates.
mirrorPod, _ := kl.podManager.GetMirrorPodByPod(pod)
kl.dispatchWork(pod, kubetypes.SyncPodUpdate, mirrorPod, start)
HandlePodRemoves遍历pod列表。
// HandlePodRemoves is the callback in the SyncHandler interface for pods
// being removed from a config source.
func (kl *Kubelet) HandlePodRemoves(pods []*v1.Pod) {
start := kl.clock.Now()
for _, pod := range pods {
...
}
}
从pod manager中删除pod。
for _, pod := range pods {
kl.podManager.DeletePod(pod)
...
}
如果是mirror pod,则对mirror pod进行处理。
if kubepod.IsMirrorPod(pod) {
kl.handleMirrorPod(pod, start)
continue
}
调用kubelet的deletePod函数来删除pod。
// Deletion is allowed to fail because the periodic cleanup routine
// will trigger deletion again.
if err := kl.deletePod(pod); err != nil {
glog.V(2).Infof("Failed to delete pod %q, err: %v", format.Pod(pod), err)
}
deletePod 函数将需要删除的pod加入podKillingCh的channel中,有podKiller监听这个channel去执行删除任务,实现如下:
// deletePod deletes the pod from the internal state of the kubelet by:
// 1. stopping the associated pod worker asynchronously
// 2. signaling to kill the pod by sending on the podKillingCh channel
//
// deletePod returns an error if not all sources are ready or the pod is not
// found in the runtime cache.
func (kl *Kubelet) deletePod(pod *v1.Pod) error {
if pod == nil {
return fmt.Errorf("deletePod does not allow nil pod")
}
if !kl.sourcesReady.AllReady() {
// If the sources aren't ready, skip deletion, as we may accidentally delete pods
// for sources that haven't reported yet.
return fmt.Errorf("skipping delete because sources aren't ready yet")
}
kl.podWorkers.ForgetWorker(pod.UID)
// Runtime cache may not have been updated to with the pod, but it's okay
// because the periodic cleanup routine will attempt to delete again later.
runningPods, err := kl.runtimeCache.GetPods()
if err != nil {
return fmt.Errorf("error listing containers: %v", err)
}
runningPod := kubecontainer.Pods(runningPods).FindPod("", pod.UID)
if runningPod.IsEmpty() {
return fmt.Errorf("pod not found")
}
podPair := kubecontainer.PodPair{APIPod: pod, RunningPod: &runningPod}
kl.podKillingCh <- &podPair
// TODO: delete the mirror pod here?
// We leave the volume/directory cleanup to the periodic cleanup routine.
return nil
}
从probe manager中移除pod。
kl.probeManager.RemovePod(pod)
遍历pod列表。
// HandlePodReconcile is the callback in the SyncHandler interface for pods
// that should be reconciled.
func (kl *Kubelet) HandlePodReconcile(pods []*v1.Pod) {
start := kl.clock.Now()
for _, pod := range pods {
...
}
}
将pod更新到pod manager中。
for _, pod := range pods {
// Update the pod in pod manager, status manager will do periodically reconcile according
// to the pod manager.
kl.podManager.UpdatePod(pod)
...
}
必要时调整pod的Ready状态,执行dispatchWork函数。
// Reconcile Pod "Ready" condition if necessary. Trigger sync pod for reconciliation.
if status.NeedToReconcilePodReadiness(pod) {
mirrorPod, _ := kl.podManager.GetMirrorPodByPod(pod)
kl.dispatchWork(pod, kubetypes.SyncPodSync, mirrorPod, start)
}
如果pod被设定为需要被驱逐的,则删除pod中的容器。
// After an evicted pod is synced, all dead containers in the pod can be removed.
if eviction.PodIsEvicted(pod.Status) {
if podStatus, err := kl.podCache.Get(pod.UID); err == nil {
kl.containerDeletor.deleteContainersInPod("", podStatus, true)
}
}
HandlePodSyncssyncHandler接口回调函数,调用dispatchWork,通过pod worker来执行任务。
// HandlePodSyncs is the callback in the syncHandler interface for pods
// that should be dispatched to pod workers for sync.
func (kl *Kubelet) HandlePodSyncs(pods []*v1.Pod) {
start := kl.clock.Now()
for _, pod := range pods {
mirrorPod, _ := kl.podManager.GetMirrorPodByPod(pod)
kl.dispatchWork(pod, kubetypes.SyncPodSync, mirrorPod, start)
}
}
HandlePodCleanups主要用来执行pod的清理任务,其中包括terminating的pod,orphaned的pod等。
首先查看pod使用到的cgroup。
// HandlePodCleanups performs a series of cleanup work, including terminating
// pod workers, killing unwanted pods, and removing orphaned volumes/pod
// directories.
// NOTE: This function is executed by the main sync loop, so it
// should not contain any blocking calls.
func (kl *Kubelet) HandlePodCleanups() error {
// The kubelet lacks checkpointing, so we need to introspect the set of pods
// in the cgroup tree prior to inspecting the set of pods in our pod manager.
// this ensures our view of the cgroup tree does not mistakenly observe pods
// that are added after the fact...
var (
cgroupPods map[types.UID]cm.CgroupName
err error
)
if kl.cgroupsPerQOS {
pcm := kl.containerManager.NewPodContainerManager()
cgroupPods, err = pcm.GetAllPodsFromCgroups()
if err != nil {
return fmt.Errorf("failed to get list of pods that still exist on cgroup mounts: %v", err)
}
}
...
}
列出所有pod包括mirror pod。
allPods, mirrorPods := kl.podManager.GetPodsAndMirrorPods()
// Pod phase progresses monotonically. Once a pod has reached a final state,
// it should never leave regardless of the restart policy. The statuses
// of such pods should not be changed, and there is no need to sync them.
// TODO: the logic here does not handle two cases:
// 1. If the containers were removed immediately after they died, kubelet
// may fail to generate correct statuses, let alone filtering correctly.
// 2. If kubelet restarted before writing the terminated status for a pod
// to the apiserver, it could still restart the terminated pod (even
// though the pod was not considered terminated by the apiserver).
// These two conditions could be alleviated by checkpointing kubelet.
activePods := kl.filterOutTerminatedPods(allPods)
desiredPods := make(map[types.UID]empty)
for _, pod := range activePods {
desiredPods[pod.UID] = empty{}
}
pod worker停止不再存在的pod的任务,并从probe manager中清除pod。
// Stop the workers for no-longer existing pods.
// TODO: is here the best place to forget pod workers?
kl.podWorkers.ForgetNonExistingPodWorkers(desiredPods)
kl.probeManager.CleanupPods(activePods)
将需要杀死的pod加入到podKillingCh的channel中,podKiller的任务会监听该channel并获取需要杀死的pod列表来执行杀死pod的操作。
runningPods, err := kl.runtimeCache.GetPods()
if err != nil {
glog.Errorf("Error listing containers: %#v", err)
return err
}
for _, pod := range runningPods {
if _, found := desiredPods[pod.ID]; !found {
kl.podKillingCh <- &kubecontainer.PodPair{APIPod: nil, RunningPod: pod}
}
}
当pod不再被绑定到该节点,移除podStatus,其中removeOrphanedPodStatuses最后调用的函数是statusManagerRemoveOrphanedStatuses方法。
kl.removeOrphanedPodStatuses(allPods, mirrorPods)
移除所有的orphaned volume。
// Remove any orphaned volumes.
// Note that we pass all pods (including terminated pods) to the function,
// so that we don't remove volumes associated with terminated but not yet
// deleted pods.
err = kl.cleanupOrphanedPodDirs(allPods, runningPods)
if err != nil {
// We want all cleanup tasks to be run even if one of them failed. So
// we just log an error here and continue other cleanup tasks.
// This also applies to the other clean up tasks.
glog.Errorf("Failed cleaning up orphaned pod directories: %v", err)
}
移除mirror pod。
// Remove any orphaned mirror pods.
kl.podManager.DeleteOrphanedMirrorPods()
删除不再运行的pod的cgroup。
// Remove any cgroups in the hierarchy for pods that are no longer running.
if kl.cgroupsPerQOS {
kl.cleanupOrphanedPodCgroups(cgroupPods, activePods)
}
执行垃圾回收(GC)操作。
kl.backOff.GC()
dispatchWork通过pod worker启动一个异步的循环。
完整代码如下:
// dispatchWork starts the asynchronous sync of the pod in a pod worker.
// If the pod is terminated, dispatchWork
func (kl *Kubelet) dispatchWork(pod *v1.Pod, syncType kubetypes.SyncPodType, mirrorPod *v1.Pod, start time.Time) {
if kl.podIsTerminated(pod) {
if pod.DeletionTimestamp != nil {
// If the pod is in a terminated state, there is no pod worker to
// handle the work item. Check if the DeletionTimestamp has been
// set, and force a status update to trigger a pod deletion request
// to the apiserver.
kl.statusManager.TerminatePod(pod)
}
return
}
// Run the sync in an async worker.
kl.podWorkers.UpdatePod(&UpdatePodOptions{
Pod: pod,
MirrorPod: mirrorPod,
UpdateType: syncType,
OnCompleteFunc: func(err error) {
if err != nil {
metrics.PodWorkerLatency.WithLabelValues(syncType.String()).Observe(metrics.SinceInMicroseconds(start))
}
},
})
// Note the number of containers for new pods.
if syncType == kubetypes.SyncPodCreate {
metrics.ContainersPerPodCount.Observe(float64(len(pod.Spec.Containers)))
}
}
以下分段进行分析:
如果pod的状态是处于Terminated状态,则执行statusManagerTerminatePod操作。
// dispatchWork starts the asynchronous sync of the pod in a pod worker.
// If the pod is terminated, dispatchWork
func (kl *Kubelet) dispatchWork(pod *v1.Pod, syncType kubetypes.SyncPodType, mirrorPod *v1.Pod, start time.Time) {
if kl.podIsTerminated(pod) {
if pod.DeletionTimestamp != nil {
// If the pod is in a terminated state, there is no pod worker to
// handle the work item. Check if the DeletionTimestamp has been
// set, and force a status update to trigger a pod deletion request
// to the apiserver.
kl.statusManager.TerminatePod(pod)
}
return
}
...
}
执行pod worker的UpdatePod函数,该函数是pod worker的核心函数,来执行pod相关操作。具体逻辑待下文分析。
// Run the sync in an async worker.
kl.podWorkers.UpdatePod(&UpdatePodOptions{
Pod: pod,
MirrorPod: mirrorPod,
UpdateType: syncType,
OnCompleteFunc: func(err error) {
if err != nil {
metrics.PodWorkerLatency.WithLabelValues(syncType.String()).Observe(metrics.SinceInMicroseconds(start))
}
},
})
当创建类型是SyncPodCreate(即创建pod的时候),统计新pod中容器的数目。
// Note the number of containers for new pods.
if syncType == kubetypes.SyncPodCreate {
metrics.ContainersPerPodCount.Observe(float64(len(pod.Spec.Containers)))
}
PodWorkers是一个接口类型:
// PodWorkers is an abstract interface for testability.
type PodWorkers interface {
UpdatePod(options *UpdatePodOptions)
ForgetNonExistingPodWorkers(desiredPods map[types.UID]empty)
ForgetWorker(uid types.UID)
}
其中UpdatePod是一个核心方法,通过podUpdates的channel来传递需要处理的pod信息,对于新创建的pod每个pod都会由一个goroutine来执行managePodLoop
此部分代码位于pkg/kubelet/pod_workers.go
// Apply the new setting to the specified pod.
// If the options provide an OnCompleteFunc, the function is invoked if the update is accepted.
// Update requests are ignored if a kill pod request is pending.
func (p *podWorkers) UpdatePod(options *UpdatePodOptions) {
pod := options.Pod
uid := pod.UID
var podUpdates chan UpdatePodOptions
var exists bool
p.podLock.Lock()
defer p.podLock.Unlock()
if podUpdates, exists = p.podUpdates[uid]; !exists {
// We need to have a buffer here, because checkForUpdates() method that
// puts an update into channel is called from the same goroutine where
// the channel is consumed. However, it is guaranteed that in such case
// the channel is empty, so buffer of size 1 is enough.
podUpdates = make(chan UpdatePodOptions, 1)
p.podUpdates[uid] = podUpdates
// Creating a new pod worker either means this is a new pod, or that the
// kubelet just restarted. In either case the kubelet is willing to believe
// the status of the pod for the first pod worker sync. See corresponding
// comment in syncPod.
go func() {
defer runtime.HandleCrash()
p.managePodLoop(podUpdates)
}()
}
if !p.isWorking[pod.UID] {
p.isWorking[pod.UID] = true
podUpdates <- *options
} else {
// if a request to kill a pod is pending, we do not let anything overwrite that request.
update, found := p.lastUndeliveredWorkUpdate[pod.UID]
if !found || update.UpdateType != kubetypes.SyncPodKill {
p.lastUndeliveredWorkUpdate[pod.UID] = *options
}
}
}
managePodLoop通过读取podUpdateschannel的信息,执行syncPodFn函数,而syncPodFn函数在newPodWorkers的时候赋值了,即kubelet.syncPodkubelet.syncPod具体代码逻辑待后续文章单独分析。
// newPodWorkers传入syncPod函数
klet.podWorkers = newPodWorkers(klet.syncPod, kubeDeps.Recorder, klet.workQueue, klet.resyncInterval, backOffPeriod, klet.podCache)
newPodWorkers函数参考:
func newPodWorkers(syncPodFn syncPodFnType, recorder record.EventRecorder, workQueue queue.WorkQueue,
resyncInterval, backOffPeriod time.Duration, podCache kubecontainer.Cache) *podWorkers {
return &podWorkers{
podUpdates: map[types.UID]chan UpdatePodOptions{},
isWorking: map[types.UID]bool{},
lastUndeliveredWorkUpdate: map[types.UID]UpdatePodOptions{},
syncPodFn: syncPodFn, // 构造传入klet.syncPod函数
recorder: recorder,
workQueue: workQueue,
resyncInterval: resyncInterval,
backOffPeriod: backOffPeriod,
podCache: podCache,
}
}
managePodLoop函数参考:
此部分代码位于pkg/kubelet/pod_workers.go
func (p *podWorkers) managePodLoop(podUpdates <-chan UpdatePodOptions) {
var lastSyncTime time.Time
for update := range podUpdates {
err := func() error {
podUID := update.Pod.UID
// This is a blocking call that would return only if the cache
// has an entry for the pod that is newer than minRuntimeCache
// Time. This ensures the worker doesn't start syncing until
// after the cache is at least newer than the finished time of
// the previous sync.
status, err := p.podCache.GetNewerThan(podUID, lastSyncTime)
if err != nil {