Integrating ContainerManager into Kubelet

cmd/kubelet/app/server.go

@@ -102,6 +102,7 @@ type KubeletServer struct {
 	ResourceContainer              string
 	CgroupRoot                     string
 	ContainerRuntime               string
+	DockerDaemonContainer          string
 
 	// Flags intended for testing
 
@@ -158,6 +159,7 @@ func NewKubeletServer() *KubeletServer {
 		ResourceContainer:           "/kubelet",
 		CgroupRoot:                  "",
 		ContainerRuntime:            "docker",
+		DockerDaemonContainer:       "/docker-daemon",
 	}
 }
 
@@ -212,6 +214,7 @@ func (s *KubeletServer) AddFlags(fs *pflag.FlagSet) {
 	fs.StringVar(&s.ResourceContainer, "resource-container", s.ResourceContainer, "Absolute name of the resource-only container to create and run the Kubelet in (Default: /kubelet).")
 	fs.StringVar(&s.CgroupRoot, "cgroup_root", s.CgroupRoot, "Optional root cgroup to use for pods. This is handled by the container runtime on a best effort basis. Default: '', which means use the container runtime default.")
 	fs.StringVar(&s.ContainerRuntime, "container_runtime", s.ContainerRuntime, "The container runtime to use. Possible values: 'docker', 'rkt'. Default: 'docker'.")
+	fs.StringVar(&s.DockerDaemonContainer, "docker-daemon-container", s.DockerDaemonContainer, "Optional resource-only container in which to place the Docker Daemon. Empty for no container (Default: /docker-daemon).")
 
 	// Flags intended for testing, not recommended used in production environments.
 	fs.BoolVar(&s.ReallyCrashForTesting, "really-crash-for-testing", s.ReallyCrashForTesting, "If true, when panics occur crash. Intended for testing.")
@@ -321,6 +324,7 @@ func (s *KubeletServer) Run(_ []string) error {
 		CgroupRoot:                s.CgroupRoot,
 		ContainerRuntime:          s.ContainerRuntime,
 		Mounter:                   mounter,
+		DockerDaemonContainer:     s.DockerDaemonContainer,
 	}
 
 	RunKubelet(&kcfg, nil)
@@ -432,6 +436,7 @@ func SimpleKubelet(client *client.Client,
 		CgroupRoot:                "",
 		ContainerRuntime:          "docker",
 		Mounter:                   mount.New(),
+		DockerDaemonContainer:     "/docker-daemon",
 	}
 	return &kcfg
 }
@@ -562,6 +567,7 @@ type KubeletConfig struct {
 	CgroupRoot                     string
 	ContainerRuntime               string
 	Mounter                        mount.Interface
+	DockerDaemonContainer          string
 }
 
 func createAndInitKubelet(kc *KubeletConfig) (k KubeletBootstrap, pc *config.PodConfig, err error) {
@@ -609,7 +615,8 @@ func createAndInitKubelet(kc *KubeletConfig) (k KubeletBootstrap, pc *config.Pod
 		kc.OSInterface,
 		kc.CgroupRoot,
 		kc.ContainerRuntime,
-		kc.Mounter)
+		kc.Mounter,
+		kc.DockerDaemonContainer)
 
 	if err != nil {
 		return nil, nil, err

pkg/kubelet/kubelet.go

@@ -136,7 +136,8 @@ func NewMainKubelet(
 	osInterface kubecontainer.OSInterface,
 	cgroupRoot string,
 	containerRuntime string,
-	mounter mount.Interface) (*Kubelet, error) {
+	mounter mount.Interface,
+	dockerDaemonContainer string) (*Kubelet, error) {
 	if rootDirectory == "" {
 		return nil, fmt.Errorf("invalid root directory %q", rootDirectory)
 	}
@@ -276,10 +277,19 @@ func NewMainKubelet(
 			return nil, err
 		}
 		klet.containerRuntime = rktRuntime
+
+		// No Docker daemon to put in a container.
+		dockerDaemonContainer = ""
 	default:
 		return nil, fmt.Errorf("unsupported container runtime %q specified", containerRuntime)
 	}
 
+	containerManager, err := newContainerManager(dockerDaemonContainer)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create the Container Manager: %v", err)
+	}
+	klet.containerManager = containerManager
+
 	// Wait for the runtime to be up with a timeout.
 	if err := waitUntilRuntimeIsUp(klet.containerRuntime, maxWaitForContainerRuntime); err != nil {
 		return nil, fmt.Errorf("timed out waiting for %q to come up: %v", containerRuntime, err)
@@ -434,6 +444,9 @@ type Kubelet struct {
 
 	// Mounter to use for volumes.
 	mounter mount.Interface
+
+	// Manager of non-Runtime containers.
+	containerManager containerManager
 }
 
 // getRootDir returns the full path to the directory under which kubelet can
@@ -624,10 +637,16 @@ func (kl *Kubelet) Run(updates <-chan PodUpdate) {
 
 	err := kl.imageManager.Start()
 	if err != nil {
-		kl.recorder.Eventf(kl.nodeRef, "imageManagerFailed", "Failed to start ImageManager %v", err)
+		kl.recorder.Eventf(kl.nodeRef, "kubeletSetupFailed", "Failed to start ImageManager %v", err)
 		glog.Errorf("Failed to start ImageManager, images may not be garbage collected: %v", err)
 	}
 
+	err = kl.containerManager.Start()
+	if err != nil {
+		kl.recorder.Eventf(kl.nodeRef, "kubeletSetupFailed", "Failed to start ContainerManager %v", err)
+		glog.Errorf("Failed to start ContainerManager, system may not be properly isolated: %v", err)
+	}
+
 	go util.Until(kl.updateRuntimeUp, 5*time.Second, util.NeverStop)
 	go kl.syncNodeStatus()
 	// Run the system oom watcher forever.