Kubernetes源码分析——controller mananger

type ControllerContext struct {
	// ClientBuilder will provide a client for this controller to use ClientBuilder controller.ControllerClientBuilder
	// InformerFactory gives access to informers for the controller.
	InformerFactory informers.SharedInformerFactory

	// ComponentConfig provides access to init options for a given controller
	ComponentConfig kubectrlmgrconfig.KubeControllerManagerConfiguration
	// DeferredDiscoveryRESTMapper is a RESTMapper that will defer
	// initialization of the RESTMapper until the first mapping is
	// requested.
	RESTMapper *restmapper.DeferredDiscoveryRESTMapper
	// AvailableResources is a map listing currently available resources
	AvailableResources map[schema.GroupVersionResource]bool
	// Cloud is the cloud provider interface for the controllers to use.
	// It must be initialized and ready to use.
	Cloud cloudprovider.Interface
	// Control for which control loops to be run
	// IncludeCloudLoops is for a kube-controller-manager running all loops
	// ExternalLoops is for a kube-controller-manager running with a cloud-controller-manager
	LoopMode ControllerLoopMode
	// Stop is the stop channel
	Stop <-chan struct{}
	// InformersStarted is closed after all of the controllers have been initialized and are running.  After this point it is safe,
	// for an individual controller to start the shared informers. Before it is closed, they should not.
	InformersStarted chan struct{}
	// ResyncPeriod generates a duration each time it is invoked; this is so that
	// multiple controllers don't get into lock-step and all hammer the apiserver
	// with list requests simultaneously.
	ResyncPeriod func() time.Duration
}

func startDeploymentController(ctx ControllerContext) (http.Handler, bool, error) {
	if !ctx.AvailableResources[schema.GroupVersionResource{Group: "apps", Version: "v1", Resource: "deployments"}] {
		return nil, false, nil
	}
	dc, err := deployment.NewDeploymentController(
		ctx.InformerFactory.Apps().V1().Deployments(),
		ctx.InformerFactory.Apps().V1().ReplicaSets(),
		ctx.InformerFactory.Core().V1().Pods(),
		ctx.ClientBuilder.ClientOrDie("deployment-controller"),
	)
	if err != nil {
		return nil, true, fmt.Errorf("error creating Deployment controller: %v", err)
	}
	go dc.Run(int(ctx.ComponentConfig.DeploymentController.ConcurrentDeploymentSyncs), ctx.Stop)
	return nil, true, nil
}

Run
	CreateControllerContext
	StartControllers
		startDeploymentController
			dc = deployment.NewDeploymentController
				注册Deployment Informer 到InformerFactory
			dc.Run
				启动一个goroutine 运行 Run 方法，Run begins watching and syncing.
	ctx.InformerFactory.Start   //启动所有注册的Informer和监听资源的事件

k8s.io/kubernetes/cmd/kube-controller-manager/app/controllermanager.go
// Run runs the KubeControllerManagerOptions.  This should never exit.
func Run(c *config.CompletedConfig) error {
    //1:拿到对kube-APIserver中资源的操作句柄,创建控制器上下文 
    ctx, err := CreateControllerContext(c, rootClientBuilder, clientBuilder, stop)
    //2:初始化的所有控制器（包括apiserver的客户端，informer的回调函数等等）
    if err := StartControllers(ctx, saTokenControllerInitFunc, NewControllerInitializers(ctx.LoopMode)); err != nil {
        glog.Fatalf("error starting controllers: %v", err)
    }
    //3:启动Informer,并完成Controller最终的启动以及资源监听机制
    ctx.InformerFactory.Start(ctx.Stop)
    close(ctx.InformersStarted)
}


func StartControllers(ctx ControllerContext, startSATokenController InitFunc, controllers map[string]InitFunc) error {
    ···
    for controllerName, initFn := range controllers {
        if !ctx.IsControllerEnabled(controllerName) {
            glog.Warningf("%q is disabled", controllerName)
            continue
        }
        time.Sleep(wait.Jitter(ctx.ComponentConfig.GenericComponent.ControllerStartInterval.Duration, ControllerStartJitter))
        glog.V(1).Infof("Starting %q", controllerName)
        //note : initFn为初始化controller是创建的初始化函数
        started, err := initFn(ctx)
        ···
    }
    return nil
}

func NewControllerInitializers(loopMode ControllerLoopMode) map[string]InitFunc {
	controllers := map[string]InitFunc{}
	controllers["endpoint"] = startEndpointController
	controllers["replicationcontroller"] = startReplicationController
	controllers["daemonset"] = startDaemonSetController
	controllers["job"] = startJobController
	controllers["deployment"] = startDeploymentController
	controllers["replicaset"] = startReplicaSetController
	...
	if loopMode == IncludeCloudLoops {
		controllers["cloud-node-lifecycle"] = startCloudNodeLifecycleController
		..
	}
	...
	return controllers
}