kubernetes源码分析controller-manager启动

kube controller manager 代码分析

1.目录: cmd/kube-controller-manager

2.main函数定义在cmd/kube-controller-manager/controller-manager.go

func main() {
	rand.Seed(time.Now().UnixNano())

	command := app.NewControllerManagerCommand()

	// TODO: once we switch everything over to Cobra commands, we can go back to calling
	// utilflag.InitFlags() (by removing its pflag.Parse() call). For now, we have to set the
	// normalize func and add the go flag set by hand.
	// utilflag.InitFlags()
	logs.InitLogs()
	defer logs.FlushLogs()

	if err := command.Execute(); err != nil {
		os.Exit(1)
	}
}

步骤: rand 生成随机数 --> 初始化command --> init log --> execute

3. NewControllerManagerCommand 定义在app目录下

   cmd/kube-controller-manager/app/controllermanager.go

   源码定义:

   func NewControllerManagerCommand() *cobra.Command {
   	s, err := options.NewKubeControllerManagerOptions()
   	if err != nil {
   		klog.Fatalf("unable to initialize command options: %v", err)
   	}
   
   	cmd := &cobra.Command{
   		Use: "kube-controller-manager",
   		Long: `The Kubernetes controller manager is a daemon that embeds
   the core control loops shipped with Kubernetes. In applications of robotics and
   automation, a control loop is a non-terminating loop that regulates the state of
   the system. In Kubernetes, a controller is a control loop that watches the shared
   state of the cluster through the apiserver and makes changes attempting to move the
   current state towards the desired state. Examples of controllers that ship with
   Kubernetes today are the replication controller, endpoints controller, namespace
   controller, and serviceaccounts controller.`,
   		PersistentPreRunE: func(*cobra.Command, []string) error {
   			// silence client-go warnings.
   			// kube-controller-manager generically watches APIs (including deprecated ones),
   			// and CI ensures it works properly against matching kube-apiserver versions.
   			restclient.SetDefaultWarningHandler(restclient.NoWarnings{})
   			return nil
   		},
   		Run: func(cmd *cobra.Command, args []string) {
   			verflag.PrintAndExitIfRequested()
   			cliflag.PrintFlags(cmd.Flags())
   
   			c, err := s.Config(KnownControllers(), ControllersDisabledByDefault.List())
   			if err != nil {
   				fmt.Fprintf(os.Stderr, "%v\n", err)
   				os.Exit(1)
   			}
   
   			if err := Run(c.Complete(), wait.NeverStop); err != nil {
   				fmt.Fprintf(os.Stderr, "%v\n", err)
   				os.Exit(1)
   			}
   		},
   		Args: func(cmd *cobra.Command, args []string) error {
   			for _, arg := range args {
   				if len(arg) > 0 {
   					return fmt.Errorf("%q does not take any arguments, got %q", cmd.CommandPath(), args)
   				}
   			}
   			return nil
   		},
   	}
   
   	fs := cmd.Flags()
   	namedFlagSets := s.Flags(KnownControllers(), ControllersDisabledByDefault.List())
   	verflag.AddFlags(namedFlagSets.FlagSet("global"))
   	globalflag.AddGlobalFlags(namedFlagSets.FlagSet("global"), cmd.Name())
   	registerLegacyGlobalFlags(namedFlagSets)
   	for _, f := range namedFlagSets.FlagSets {
   		fs.AddFlagSet(f)
   	}
   	usageFmt := "Usage:\n  %s\n"
   	cols, _, _ := term.TerminalSize(cmd.OutOrStdout())
   	cmd.SetUsageFunc(func(cmd *cobra.Command) error {
   		fmt.Fprintf(cmd.OutOrStderr(), usageFmt, cmd.UseLine())
   		cliflag.PrintSections(cmd.OutOrStderr(), namedFlagSets, cols)
   		return nil
   	})
   	cmd.SetHelpFunc(func(cmd *cobra.Command, args []string) {
   		fmt.Fprintf(cmd.OutOrStdout(), "%s\n\n"+usageFmt, cmd.Long, cmd.UseLine())
   		cliflag.PrintSections(cmd.OutOrStdout(), namedFlagSets, cols)
   	})
   
   	return cmd
   }
   

   1).NewControllerManagerCommand 返回 cobra.Command对象

   2).

   cmd := &cobra.Command{
   		Use: "kube-controller-manager",
   		...
   		}
   

   定义command信息

   3). 定义options

   s, err := options.NewKubeControllerManagerOptions()
   

   4.NewKubeControllerManagerOptions定义在cmd/kube-controller-manager/app/options/options.go

   
   // KubeControllerManagerOptions is the main context object for the kube-controller manager.
   type KubeControllerManagerOptions struct {
   	Generic           *cmoptions.GenericControllerManagerConfigurationOptions
   	KubeCloudShared   *cpoptions.KubeCloudSharedOptions
   	ServiceController *cpoptions.ServiceControllerOptions
   
   	AttachDetachController           *AttachDetachControllerOptions
   	CSRSigningController             *CSRSigningControllerOptions
   	DaemonSetController              *DaemonSetControllerOptions
   	DeploymentController             *DeploymentControllerOptions
   	StatefulSetController            *StatefulSetControllerOptions
   	DeprecatedFlags                  *DeprecatedControllerOptions
   	EndpointController               *EndpointControllerOptions
   	EndpointSliceController          *EndpointSliceControllerOptions
   	EndpointSliceMirroringController *EndpointSliceMirroringControllerOptions
   	GarbageCollectorController       *GarbageCollectorControllerOptions
   	HPAController                    *HPAControllerOptions
   	JobController                    *JobControllerOptions
   	CronJobController                *CronJobControllerOptions
   	NamespaceController              *NamespaceControllerOptions
   	NodeIPAMController               *NodeIPAMControllerO