【kubernetes/k8s源码分析】kube-controller-manager之endpoint controller源码分析

1 EndpointController 结构体

• client: 调用 apiserver 接口
• queue: 处理的队列

// EndpointController manages selector-based service endpoints.type EndpointController struct {       client clientset.Interface              serviceLister corelisters.ServiceLister       servicesSynced cache.InformerSynced              podLister corelisters.PodLister       podsSynced cache.InformerSynced              endpointsLister corelisters.EndpointsLister       endpointsSynced cache.InformerSynced       queue workqueue.RateLimitingInterface       workerLoopPeriod time.Duration}

 

2 结构体初始化

   初始化 EndpointController 结构体，将 service 以及 pod 进行 serviceInformer podInformer 赋值

// NewEndpointController returns a new *EndpointController.func NewEndpointController(podInformer coreinformers.PodInformer, serviceInformer coreinformers.ServiceInformer,       endpointsInformer coreinformers.EndpointsInformer, client clientset.Interface) *EndpointController {       if client != nil && client.Core().RESTClient().GetRateLimiter() != nil {              metrics.RegisterMetricAndTrackRateLimiterUsage("endpoint_controller", client.Core().RESTClient().GetRateLimiter())       }       e := &EndpointController{              client:           client,              queue:            workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "endpoint"),              workerLoopPeriod: time.Second,       }       serviceInformer.Informer().AddEventHandler(cache.ResourceEventHandlerFuncs{              AddFunc: e.enqueueService,              UpdateFunc: func(old, cur interface{}) {                     e.enqueueService(cur)              },              DeleteFunc: e.enqueueService,       })       e.serviceLister = serviceInformer.Lister()       e.servicesSynced = serviceInformer.Informer().HasSynced       podInformer.Informer().AddEventHandler(cache.ResourceEventHandlerFuncs{              AddFunc:    e.addPod,              UpdateFunc: e.updatePod,              DeleteFunc: e.deletePod,       })       e.podLister = podInformer.Lister()       e.podsSynced = podInformer.Informer().HasSynced       e.endpointsLister = endpointsInformer.Lister()       e.endpointsSynced = endpointsInformer.Informer().HasSynced       return e}

3 endpoint controller 启动

    goroutine 创建一个 endpointController 结构体并调用其 Run 方法

func startEndpointController(ctx ControllerContext) (bool, error) {       go endpointcontroller.NewEndpointController(              ctx.InformerFactory.Core().V1().Pods(),              ctx.InformerFactory.Core().V1().Services(),              ctx.InformerFactory.Core().V1().Endpoints(),              ctx.ClientBuilder.ClientOrDie("endpoint-controller"),       ).Run(int(ctx.Options.ConcurrentEndpointSyncs), ctx.Stop)       return true, nil}

    3.1 Run 函数中 WaitForCacheSync 等待同步 pod service endpoint cache，然后启动几个 goroutine 工作处理

func (e *EndpointController) Run(workers int, stopCh <-chan struct{}) {       defer utilruntime.HandleCrash()       defer e.queue.ShutDown()       if !controller.WaitForCacheSync("endpoint", stopCh, e.podsSynced, e.servicesSynced, e.endpointsSynced) {              return       }       for i := 0; i < workers; i++ {              go wait.Until(e.worker, e.workerLoopPeriod, stopCh)       }       go func() {              defer utilruntime.HandleCrash()              e.checkLeftoverEndpoints()       }()       <-stopCh}

    3.1.1 Worker循环处理，从队列中取出 key，调用 syncService 函数处理，第四章节讲解 syncService 函数

func (e *EndpointController) worker() {       for e.processNextWorkItem() {       }}func (e *EndpointController) processNextWorkItem() bool {       eKey, quit := e.queue.Get()       if quit {              return false       }       defer e.queue.Done(eKey)       err := e.syncService(eKey.(string))       e.handleErr(err, eKey)       return true}

4 syncService 函数

func (e *EndpointController) syncService(key string) error

    4.1 把 key 根据 / 拆分为 namespace 和 name，根据其获得 service

namespace, name, err := cache.SplitMetaNamespaceKey(key)if err != nil {       return err}service, err := e.serviceLister.Services(namespace).Get(name)if err != nil {       // Delete the corresponding endpoint, as the service has been deleted.       // TODO: Please note that this will delete an endpoint when a       // service is deleted. However, if we're down at the time when       // the service is deleted, we will miss that deletion, so this       // doesn't completely solve the problem. See #6877.       err = e.client.Core().Endpoints(namespace).Delete(name, nil)       if err != nil && !errors.IsNotFound(err) {              return err       }       return nil}

    4.2 获得相关的 pods

pods, err := e.podLister.Pods(service.Namespace).List(labels.Set(service.Spec.Selector).AsSelectorPreValidated())if err != nil {       // Since we're getting stuff from a local cache, it is       // basically impossible to get this error.       return err}

    4,3 根据 namespace 和 name 查询所有 endpoints

// See if there's actually an update here.currentEndpoints, err := e.endpointsLister.Endpoints(service.Namespace).Get(service.Name)if err != nil {       if errors.IsNotFound(err) {              currentEndpoints = &v1.Endpoints{                     ObjectMeta: metav1.ObjectMeta{                            Name:   service.Name,                            Labels: service.Labels,                     },              }       } else {              return err       }}

    4.4 如果先前没有就调用 Create 接口创建，有的话就更新

createEndpoints := len(currentEndpoints.ResourceVersion) == 0if createEndpoints {       // No previous endpoints, create them       _, err = e.client.Core().Endpoints(service.Namespace).Create(newEndpoints)} else {       // Pre-existing       _, err = e.client.Core().Endpoints(service.Namespace).Update(newEndpoints)}if err != nil {       if createEndpoints && errors.IsForbidden(err) {              // A request is forbidden primarily for two reasons:              // 1. namespace is terminating, endpoint creation is not allowed by default.              // 2. policy is misconfigured, in which case no service would function anywhere.              // Given the frequency of 1, we log at a lower level.              glog.V(5).Infof("Forbidden from creating endpoints: %v", err)       }       return err}

2 WaitForCacheSync 函数

    2.1 WaitForCacheSync 函数等待