kubelet: Rename RunContainerOptionsGenerator to RuntimeHelper.

Also add GetClusterDNS() to the interface to let rkt get the
DNS servers, DNS names.

pkg/kubelet/container/helpers.go

@@ -36,10 +36,11 @@ type HandlerRunner interface {
 	Run(containerID ContainerID, pod *api.Pod, container *api.Container, handler *api.Handler) error
 }
 
-// RunContainerOptionsGenerator generates the options that necessary for
-// container runtime to run a container.
-type RunContainerOptionsGenerator interface {
+// RuntimeHelper wraps kubelet to make container runtime
+// able to get necessary informations like the RunContainerOptions, DNS settings.
+type RuntimeHelper interface {
 	GenerateRunContainerOptions(pod *api.Pod, container *api.Container) (*RunContainerOptions, error)
+	GetClusterDNS(pod *api.Pod) (dnsServers []string, dnsSearches []string, err error)
 }
 
 // ShouldContainerBeRestarted checks whether a container needs to be restarted.

pkg/kubelet/dockertools/fake_manager.go

@@ -40,13 +40,13 @@ func NewFakeDockerManager(
 	containerLogsDir string,
 	osInterface kubecontainer.OSInterface,
 	networkPlugin network.NetworkPlugin,
-	generator kubecontainer.RunContainerOptionsGenerator,
+	runtimeHelper kubecontainer.RuntimeHelper,
 	httpClient kubetypes.HttpGetter, imageBackOff *util.Backoff) *DockerManager {
 
 	fakeOOMAdjuster := oom.NewFakeOOMAdjuster()
 	fakeProcFs := procfs.NewFakeProcFS()
 	dm := NewDockerManager(client, recorder, livenessManager, containerRefManager, machineInfo, podInfraContainerImage, qps,
-		burst, containerLogsDir, osInterface, networkPlugin, generator, httpClient, &NativeExecHandler{},
+		burst, containerLogsDir, osInterface, networkPlugin, runtimeHelper, httpClient, &NativeExecHandler{},
 		fakeOOMAdjuster, fakeProcFs, false, imageBackOff, true)
 	dm.dockerPuller = &FakeDockerPuller{}
 	return dm

pkg/kubelet/dockertools/manager.go

@@ -129,8 +129,8 @@ type DockerManager struct {
 	// Health check results.
 	livenessManager proberesults.Manager
 
-	// Generator of runtime container options.
-	generator kubecontainer.RunContainerOptionsGenerator
+	// RuntimeHelper that wraps kubelet to generate runtime container options.
+	runtimeHelper kubecontainer.RuntimeHelper
 
 	// Runner of lifecycle events.
 	runner kubecontainer.HandlerRunner
@@ -163,7 +163,7 @@ func NewDockerManager(
 	containerLogsDir string,
 	osInterface kubecontainer.OSInterface,
 	networkPlugin network.NetworkPlugin,
-	generator kubecontainer.RunContainerOptionsGenerator,
+	runtimeHelper kubecontainer.RuntimeHelper,
 	httpClient kubetypes.HttpGetter,
 	execHandler ExecHandler,
 	oomAdjuster *oom.OOMAdjuster,
@@ -217,7 +217,7 @@ func NewDockerManager(
 		containerLogsDir:       containerLogsDir,
 		networkPlugin:          networkPlugin,
 		livenessManager:        livenessManager,
-		generator:              generator,
+		runtimeHelper:          runtimeHelper,
 		execHandler:            execHandler,
 		oomAdjuster:            oomAdjuster,
 		procFs:                 procFs,
@@ -1533,7 +1533,7 @@ func (dm *DockerManager) runContainerInPod(pod *api.Pod, container *api.Containe
 		glog.Errorf("Can't make a ref to pod %v, container %v: '%v'", pod.Name, container.Name, err)
 	}
 
-	opts, err := dm.generator.GenerateRunContainerOptions(pod, container)
+	opts, err := dm.runtimeHelper.GenerateRunContainerOptions(pod, container)
 	if err != nil {
 		return kubecontainer.ContainerID{}, fmt.Errorf("GenerateRunContainerOptions: %v", err)
 	}

pkg/kubelet/dockertools/manager_test.go

@@ -58,13 +58,15 @@ func (f *fakeHTTP) Get(url string) (*http.Response, error) {
 	return nil, f.err
 }
 
-type fakeOptionGenerator struct{}
+// fakeRuntimeHelper implementes kubecontainer.RuntimeHelper inter
+// faces for testing purposes.
+type fakeRuntimeHelper struct{}
 
-var _ kubecontainer.RunContainerOptionsGenerator = &fakeOptionGenerator{}
+var _ kubecontainer.RuntimeHelper = &fakeRuntimeHelper{}
 
 var testPodContainerDir string
 
-func (*fakeOptionGenerator) GenerateRunContainerOptions(pod *api.Pod, container *api.Container) (*kubecontainer.RunContainerOptions, error) {
+func (f *fakeRuntimeHelper) GenerateRunContainerOptions(pod *api.Pod, container *api.Container) (*kubecontainer.RunContainerOptions, error) {
 	var opts kubecontainer.RunContainerOptions
 	var err error
 	if len(container.TerminationMessagePath) != 0 {
@@ -77,12 +79,15 @@ func (*fakeOptionGenerator) GenerateRunContainerOptions(pod *api.Pod, container
 	return &opts, nil
 }
 
+func (f *fakeRuntimeHelper) GetClusterDNS(pod *api.Pod) ([]string, []string, error) {
+	return nil, nil, fmt.Errorf("not implemented")
+}
+
 func newTestDockerManagerWithHTTPClient(fakeHTTPClient *fakeHTTP) (*DockerManager, *FakeDockerClient) {
 	fakeDocker := NewFakeDockerClient()
 	fakeRecorder := &record.FakeRecorder{}
 	containerRefManager := kubecontainer.NewRefManager()
 	networkPlugin, _ := network.InitNetworkPlugin([]network.NetworkPlugin{}, "", network.NewFakeHost(nil))
-	optionGenerator := &fakeOptionGenerator{}
 	dockerManager := NewFakeDockerManager(
 		fakeDocker,
 		fakeRecorder,
@@ -93,7 +98,7 @@ func newTestDockerManagerWithHTTPClient(fakeHTTPClient *fakeHTTP) (*DockerManage
 		0, 0, "",
 		kubecontainer.FakeOS{},
 		networkPlugin,
-		optionGenerator,
+		&fakeRuntimeHelper{},
 		fakeHTTPClient,
 		util.NewBackOff(time.Second, 300*time.Second))
 

pkg/kubelet/kubelet.go

@@ -1288,7 +1288,7 @@ func (kl *Kubelet) GenerateRunContainerOptions(pod *api.Pod, container *api.Cont
 		}
 	}
 
-	opts.DNS, opts.DNSSearch, err = kl.getClusterDNS(pod)
+	opts.DNS, opts.DNSSearch, err = kl.GetClusterDNS(pod)
 	if err != nil {
 		return nil, err
 	}
@@ -1457,9 +1457,9 @@ func (kl *Kubelet) podFieldSelectorRuntimeValue(fs *api.ObjectFieldSelector, pod
 	return fieldpath.ExtractFieldPathAsString(pod, internalFieldPath)
 }
 
-// getClusterDNS returns a list of the DNS servers and a list of the DNS search
+// GetClusterDNS returns a list of the DNS servers and a list of the DNS search
 // domains of the cluster.
-func (kl *Kubelet) getClusterDNS(pod *api.Pod) ([]string, []string, error) {
+func (kl *Kubelet) GetClusterDNS(pod *api.Pod) ([]string, []string, error) {
 	var hostDNS, hostSearch []string
 	// Get host DNS settings
 	if kl.resolverConfig != "" {