dockershim: call DockerService.Start() during grpc server startup

cmd/kubelet/app/server.go

@@ -998,10 +998,6 @@ func RunDockershim(f *options.KubeletFlags, c *kubeletconfiginternal.KubeletConf
 	if err != nil {
 		return err
 	}
-	if err := ds.Start(); err != nil {
-		return err
-	}
-
 	glog.V(2).Infof("Starting the GRPC server for the docker CRI shim.")
 	server := dockerremote.NewDockerServer(f.RemoteRuntimeEndpoint, ds)
 	if err := server.Start(); err != nil {

pkg/kubelet/dockershim/docker_service.go

@@ -266,6 +266,8 @@ func NewDockerService(config *ClientConfig, podSandboxImage string, streamingCon
 type CRIService interface {
 	runtimeapi.RuntimeServiceServer
 	runtimeapi.ImageServiceServer
+
+	Start() error
 }
 
 // DockerService is an interface that embeds the new RuntimeService and
@@ -273,7 +275,6 @@ type CRIService interface {
 type DockerService interface {
 	CRIService
 
-	Start() error
 	// For serving streaming calls.
 	http.Handler
 

pkg/kubelet/dockershim/remote/docker_server.go

@@ -48,6 +48,12 @@ func NewDockerServer(endpoint string, s dockershim.CRIService) *DockerServer {
 
 // Start starts the dockershim grpc server.
 func (s *DockerServer) Start() error {
+	// Start the internal service.
+	if err := s.service.Start(); err != nil {
+		glog.Errorf("Unable to start docker service")
+		return err
+	}
+
 	glog.V(2).Infof("Start dockershim grpc server")
 	l, err := util.CreateListener(s.endpoint)
 	if err != nil {

pkg/kubelet/kubelet.go

@@ -610,9 +610,6 @@ func NewMainKubelet(kubeCfg *kubeletconfiginternal.KubeletConfiguration,
 			if err != nil {
 				return nil, err
 			}
-			if err := ds.Start(); err != nil {
-				return nil, err
-			}
 			// For now, the CRI shim redirects the streaming requests to the
 			// kubelet, which handles the requests using DockerService..
 			klet.criHandler = ds