kubelet/runtime: add method to return pod network namespace path

pkg/kubelet/container/runtime.go

@@ -97,6 +97,12 @@ type Runtime interface {
 	RemoveImage(image ImageSpec) error
 	// Returns Image statistics.
 	ImageStats() (*ImageStats, error)
+	// Returns the filesystem path of the pod's network namespace; if the
+	// runtime does not handle namespace creation itself, or cannot return
+	// the network namespace path, it should return an error.
+	// TODO: Change ContainerID to a Pod ID since the namespace is shared
+	// by all containers in the pod.
+	GetNetNS(containerID ContainerID) (string, error)
 	// TODO(vmarmol): Unify pod and containerID args.
 	// GetContainerLogs returns logs of a specific container. By
 	// default, it returns a snapshot of the container log. Set 'follow' to true to

pkg/kubelet/container/testing/fake_runtime.go

@@ -338,6 +338,14 @@ func (f *FakeRuntime) PortForward(pod *Pod, port uint16, stream io.ReadWriteClos
 	return f.Err
 }
 
+func (f *FakeRuntime) GetNetNS(containerID ContainerID) (string, error) {
+	f.Lock()
+	defer f.Unlock()
+
+	f.CalledFunctions = append(f.CalledFunctions, "GetNetNS")
+	return "", f.Err
+}
+
 func (f *FakeRuntime) GarbageCollect(gcPolicy ContainerGCPolicy) error {
 	f.Lock()
 	defer f.Unlock()

pkg/kubelet/container/testing/runtime_mock.go

@@ -128,6 +128,11 @@ func (r *Mock) PortForward(pod *Pod, port uint16, stream io.ReadWriteCloser) err
 	return args.Error(0)
 }
 
+func (r *Mock) GetNetNS(containerID ContainerID) (string, error) {
+	args := r.Called(containerID)
+	return "", args.Error(0)
+}
+
 func (r *Mock) GarbageCollect(gcPolicy ContainerGCPolicy) error {
 	args := r.Called(gcPolicy)
 	return args.Error(0)

pkg/kubelet/network/kubenet/kubenet_linux.go

@@ -34,7 +34,6 @@ import (
 	"github.com/golang/glog"
 	"k8s.io/kubernetes/pkg/apis/componentconfig"
 	kubecontainer "k8s.io/kubernetes/pkg/kubelet/container"
-	"k8s.io/kubernetes/pkg/kubelet/dockertools"
 	"k8s.io/kubernetes/pkg/kubelet/network"
 	"k8s.io/kubernetes/pkg/util/bandwidth"
 	utilexec "k8s.io/kubernetes/pkg/util/exec"
@@ -266,11 +265,7 @@ func (plugin *kubenetNetworkPlugin) SetUpPod(namespace string, name string, id k
 		return fmt.Errorf("Kubenet cannot SetUpPod: %v", err)
 	}
 
-	runtime, ok := plugin.host.GetRuntime().(*dockertools.DockerManager)
-	if !ok {
-		return fmt.Errorf("Kubenet execution called on non-docker runtime")
-	}
-	netnsPath, err := runtime.GetNetNS(id)
+	netnsPath, err := plugin.host.GetRuntime().GetNetNS(id)
 	if err != nil {
 		return fmt.Errorf("Kubenet failed to retrieve network namespace path: %v", err)
 	}
@@ -330,11 +325,7 @@ func (plugin *kubenetNetworkPlugin) TearDownPod(namespace string, name string, i
 		return fmt.Errorf("Kubenet needs a PodCIDR to tear down pods")
 	}
 
-	runtime, ok := plugin.host.GetRuntime().(*dockertools.DockerManager)
-	if !ok {
-		return fmt.Errorf("Kubenet execution called on non-docker runtime")
-	}
-	netnsPath, err := runtime.GetNetNS(id)
+	netnsPath, err := plugin.host.GetRuntime().GetNetNS(id)
 	if err != nil {
 		return err
 	}
@@ -373,12 +364,8 @@ func (plugin *kubenetNetworkPlugin) GetPodNetworkStatus(namespace string, name s
 			return &network.PodNetworkStatus{IP: ip}, nil
 		}
 	}
-	// TODO: remove type conversion once kubenet supports multiple runtime
-	runtime, ok := plugin.host.GetRuntime().(*dockertools.DockerManager)
-	if !ok {
-		return nil, fmt.Errorf("Kubenet execution called on non-docker runtime")
-	}
-	netnsPath, err := runtime.GetNetNS(id)
+
+	netnsPath, err := plugin.host.GetRuntime().GetNetNS(id)
 	if err != nil {
 		return nil, fmt.Errorf("Kubenet failed to retrieve network namespace path: %v", err)
 	}

pkg/kubelet/rkt/rkt.go

@@ -1488,6 +1488,11 @@ func podIsActive(pod *rktapi.Pod) bool {
 		pod.State == rktapi.PodState_POD_STATE_RUNNING
 }
 
+// GetNetNS returns the network namespace path for the given container
+func (r *Runtime) GetNetNS(containerID kubecontainer.ContainerID) (string, error) {
+       return "", nil
+}
+
 // GarbageCollect collects the pods/containers.
 // After one GC iteration:
 // - The deleted pods will be removed.