本篇内容介绍了“Kubernetes PodGC Controller怎么配置”的有关知识，在实际案例的操作过程中，不少人都会遇到这样的困境，接下来就让小编带领大家学习一下如何处理这些情况吧！希望大家仔细阅读，能够学有所成！
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PodGC Controller配置
关于PodGC Controller的相关配置（kube-controller-manager配置），一共只有两个：
| flag | default value | comments | | --controllers stringSlice | * | 这里配置需要enable的controlllers列表，podgc当然也可以在这里设置是都要enable or disable，默认podgc是在enable列表中的。 |
| --terminated-pod-gc-threshold int32 | 12500 | Number of terminated pods that can exist before the terminated pod garbage collector starts deleting terminated pods. If <= 0, the terminated pod garbage collector is disabled. (default 12500) |
PodGC Controller入口
PodGC Controller是在kube-controller-manager Run的时候启动的。CMServer Run时会invoke StartControllers将预先注册的enabled Controllers遍历并逐个启动。
cmd/kube-controller-manager/app/controllermanager.go:180
func Run(s *options.CMServer) error {
...
err := StartControllers(newControllerInitializers(), s, rootClientBuilder, clientBuilder, stop)
...
}在newControllerInitializers注册了所有一些常规Controllers及其对应的start方法，为什么说这些是常规的Controllers呢，因为还有一部分Controllers没在这里进行注册，比如非常重要的service Controller，node Controller等，我把这些称为非常规Controllers。
func newControllerInitializers() map[string]InitFunc {
controllers := map[string]InitFunc{}
controllers["endpoint"] = startEndpointController
...
controllers["podgc"] = startPodGCController
...
return controllers
}因此CMServer最终是invoke startPodGCController来启动PodGC Controller的。
cmd/kube-controller-manager/app/core.go:66
func startPodGCController(ctx ControllerContext) (bool, error) {
go podgc.NewPodGC(
ctx.ClientBuilder.ClientOrDie("pod-garbage-collector"),
ctx.InformerFactory.Core().V1().Pods(),
int(ctx.Options.TerminatedPodGCThreshold),
).Run(ctx.Stop)
return true, nil
}startPodGCController内容很简单，启动一个goruntine协程，创建PodGC并启动执行。
PodGC Controller的创建
我们先来看看PodGCController的定义。
pkg/controller/podgc/gc_controller.go:44
type PodGCController struct {
kubeClient clientset.Interface
podLister corelisters.PodLister
podListerSynced cache.InformerSynced
deletePod func(namespace, name string) error
terminatedPodThreshold int
}kubeClient: 用来跟APIServer通信的client。
PodLister: PodLister helps list Pods.
podListerSynced: 用来判断PodLister是否Has Synced。
deletePod: 调用apiserver删除对应pod的接口。
terminatedPodThreshold: 对应--terminated-pod-gc-threshold的配置，默认为12500。
pkg/controller/podgc/gc_controller.go:54
func NewPodGC(kubeClient clientset.Interface, podInformer coreinformers.PodInformer, terminatedPodThreshold int) *PodGCController {
if kubeClient != nil && kubeClient.Core().RESTClient().GetRateLimiter() != nil {
metrics.RegisterMetricAndTrackRateLimiterUsage("gc_controller", kubeClient.Core().RESTClient().GetRateLimiter())
}
gcc := &PodGCController{
kubeClient: kubeClient,
terminatedPodThreshold: terminatedPodThreshold,
deletePod: func(namespace, name string) error {
glog.Infof("PodGC is force deleting Pod: %v:%v", namespace, name)
return kubeClient.Core().Pods(namespace).Delete(name, metav1.NewDeleteOptions(0))
},
}
gcc.podLister = podInformer.Lister()
gcc.podListerSynced = podInformer.Informer().HasSynced
return gcc
}创建PodGC Controller时其实只是把相关的PodGCController元素进行赋值。注意deletePod方法定义时的参数metav1.NewDeleteOptions(0)，表示立即删除pod，没有grace period。
PodGC Controller的运行
创建完PodGC Controller后，接下来就是执行Run方法启动执行了。
pkg/controller/podgc/gc_controller.go:73
func (gcc *PodGCController) Run(stop <-chan struct{}) {
if !cache.WaitForCacheSync(stop, gcc.podListerSynced) {
utilruntime.HandleError(fmt.Errorf("timed out waiting for caches to sync"))
return
}
go wait.Until(gcc.gc, gcCheckPeriod, stop)
<-stop
}pkg/controller/podgc/gc_controller.go:83
func (gcc *PodGCController) gc() {
pods, err := gcc.podLister.List(labels.Everything())
if err != nil {
glog.Errorf("Error while listing all Pods: %v", err)
return
}
if gcc.terminatedPodThreshold > 0 {
gcc.gcTerminated(pods)
}
gcc.gcOrphaned(pods)
gcc.gcUnscheduledTerminating(pods)
}gcc.gc是最终的pod回收逻辑：
调从PodLister中去除所有的pods（不设置过滤）
如果terminatedPodThreshold大于0，则调用gcc.gcTerminated(pods)回收那些超出Threshold的Pods。
调用gcc.gcOrphaned(pods)回收Orphaned pods。
调用gcc.gcUnscheduledTerminating(pods)回收UnscheduledTerminating pods。
注意：
gcTerminated和gcOrphaned，gcUnscheduledTerminating这三个gc都是串行执行的。
gcTerminated删除超出阈值的pods的删除动作是并行的，通过sync.WaitGroup等待所有对应的pods删除完成后，gcTerminated才会结束返回，才能开始后面的gcOrphaned.
gcOrphaned，gcUnscheduledTerminatin，gcUnscheduledTerminatin内部都是串行gc pods的。
回收那些Terminated的pods
func (gcc *PodGCController) gcTerminated(pods []*v1.Pod) {
terminatedPods := []*v1.Pod{}
for _, pod := range pods {
if isPodTerminated(pod) {
terminatedPods = append(terminatedPods, pod)
}
}
terminatedPodCount := len(terminatedPods)
sort.Sort(byCreationTimestamp(terminatedPods))
deleteCount := terminatedPodCount - gcc.terminatedPodThreshold
if deleteCount > terminatedPodCount {
deleteCount = terminatedPodCount
}
if deleteCount > 0 {
glog.Infof("garbage collecting %v pods", deleteCount)
}
var wait sync.WaitGroup
for i := 0; i < deleteCount; i++ {
wait.Add(1)
go func(namespace string, name string) {
defer wait.Done()
if err := gcc.deletePod(namespace, name); err != nil {
// ignore not founds
defer utilruntime.HandleError(err)
}
}(terminatedPods[i].Namespace, terminatedPods[i].Name)
}
wait.Wait()
}遍历所有pods，过滤出所有Terminated Pods（Pod.Status.Phase不为Pending, Running, Unknow的Pods）.
计算terminated pods数与terminatedPodThreshold的(超出)差值deleteCount。
启动deleteCount数量的goruntine协程，并行调用gcc.deletePod（invoke apiserver's api）方法立刻删除对应的pod。
回收那些Binded的Nodes已经不存在的pods
// gcOrphaned deletes pods that are bound to nodes that don't exist.
func (gcc *PodGCController) gcOrphaned(pods []*v1.Pod) {
glog.V(4).Infof("GC'ing orphaned")
// We want to get list of Nodes from the etcd, to make sure that it's as fresh as possible.
nodes, err := gcc.kubeClient.Core().Nodes().List(metav1.ListOptions{})
if err != nil {
return
}
nodeNames := sets.NewString()
for i := range nodes.Items {
nodeNames.Insert(nodes.Items[i].Name)
}
for _, pod := range pods {
if pod.Spec.NodeName == "" {
continue
}
if nodeNames.Has(pod.Spec.NodeName) {
continue
}
glog.V(2).Infof("Found orphaned Pod %v assigned to the Node %v. Deleting.", pod.Name, pod.Spec.NodeName)
if err := gcc.deletePod(pod.Namespace, pod.Name); err != nil {
utilruntime.HandleError(err)
} else {
glog.V(0).Infof("Forced deletion of orphaned Pod %s succeeded", pod.Name)
}
}
}gcOrphaned用来删除那些bind的node已经不存在的pods。
回收Unscheduled并且Terminating的pods
pkg/controller/podgc/gc_controller.go:167
// gcUnscheduledTerminating deletes pods that are terminating and haven't been scheduled to a particular node.
func (gcc *PodGCController) gcUnscheduledTerminating(pods []*v1.Pod) {
glog.V(4).Infof("GC'ing unscheduled pods which are terminating.")
for _, pod := range pods {
if pod.DeletionTimestamp == nil || len(pod.Spec.NodeName) > 0 {
continue
}
glog.V(2).Infof("Found unscheduled terminating Pod %v not assigned to any Node. Deleting.", pod.Name)
if err := gcc.deletePod(pod.Namespace, pod.Name); err != nil {
utilruntime.HandleError(err)
} else {
glog.V(0).Infof("Forced deletion of unscheduled terminating Pod %s succeeded", pod.Name)
}
}
}gcUnscheduledTerminating删除那些terminating并且还没调度到某个node的pods。
“Kubernetes PodGC Controller怎么配置”的内容就介绍到这里了，感谢大家的阅读。如果想了解更多行业相关的知识可以关注创新互联网站，小编将为大家输出更多高质量的实用文章！
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