client-go 分析Shutdown方法耗时长原因

k8s v1.19.0

Shutdown等待结束流程

第1步：reflector停止list/watch。

第2步：DeltaFifo队列关闭，元素全部取出，放入用户队列。

第3步：等待业务处理完成。

场景1：Shutdown方法等待EventHandler回调方法完成

klog.InitFlags(nil)
flag.Parse()
defer klog.Flush()
 
cfg, err := clientcmd.BuildConfigFromFlags("", "/root/.kube/config")
if err != nil {
	klog.Fatalf("Error building kubeconfig: %s", err.Error())
}
 
kubeClient, err := kubernetes.NewForConfig(cfg)
if err != nil {
	klog.Fatalf("Error building kubernetes clientset: %s", err.Error())
}
 
informerFactory := informers.NewSharedInformerFactory(kubeClient, 0)
hasSynced := informerFactory.Core().V1().Nodes().Informer().HasSynced
informerFactory.Core().V1().Nodes().Lister()
informerFactory.Core().V1().Nodes().Informer().AddEventHandler(cache.ResourceEventHandlerFuncs{
	AddFunc: func(obj interface{}) {
		klog.Infof("handle node add")
		time.Sleep(time.Minute)
	},
})
 
newStopCh := make(chan struct{})
informerFactory.Start(newStopCh)
 
klog.Infof("begin to wait cache sync")
if ok := cache.WaitForCacheSync(newStopCh, hasSynced); !ok {
	klog.Fatalf("failed to wait for caches to sync")
}
klog.Infof("wait cache sync end")
 
time.Sleep(5 * time.Second)
 
close(newStopCh)
 
klog.Infof("begin to shutdown")
informerFactory.Shutdown()
klog.Infof("shutdown end")

Shutdown方法等待EventHandler中AddFunc处理完成，耗时55s。