Sync static pods from Kubelet to the API server

Currently, API server is not aware of the static pods (manifests from
sources other than the API server, e.g. file and http) at all. This is
inconvenient since users cannot check the static pods through kubectl.
It is also sub-optimal because scheduler is unaware of the resource
consumption by these static pods on the node.

This change syncs the information back to the API server by creating a
mirror pod via API server for each static pod.

 - Kubelet creates containers for the static pod, as it would do
   normally.

 - If a mirror pod gets deleted, Kubelet will re-create one. The
   containers are sync'd to the static pods, so they will not be
   affected.

 - If a static pod gets removed from the source (e.g. manifest file
   removed from the directory), the orphaned mirror pod will be deleted.

Note that because events are associated with UID, and the mirror pod has
a different UID than the original static pod, the events will not be
shown for the mirror pod when running `kubectl describe pod
<mirror_pod>`.

pkg/kubelet/types.go

@@ -18,11 +18,13 @@ package kubelet
 
 import (
 	"fmt"
+	"strings"
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
 )
 
 const ConfigSourceAnnotationKey = "kubernetes.io/config.source"
+const ConfigMirrorAnnotationKey = "kubernetes.io/config.mirror"
 
 // PodOperation defines what changes will be made on a pod configuration.
 type PodOperation int
@@ -49,6 +51,9 @@ const (
 	// Updates from all sources
 	AllSource = "*"
 
+	// Used for ConfigMirrorAnnotationKey.
+	MirrorType = "mirror"
+
 	NamespaceDefault = api.NamespaceDefault
 )
 
@@ -67,7 +72,7 @@ type PodUpdate struct {
 	Source string
 }
 
-// GetPodFullName returns a name that uniquely identifies a pod across all config sources.
+// GetPodFullName returns a name that uniquely identifies a pod.
 func GetPodFullName(pod *api.Pod) string {
 	// Use underscore as the delimiter because it is not allowed in pod name
 	// (DNS subdomain format), while allowed in the container name format.
@@ -78,3 +83,12 @@ func GetPodFullName(pod *api.Pod) string {
 func BuildPodFullName(name, namespace string) string {
 	return name + "_" + namespace
 }
+
+// Parse the pod full name.
+func ParsePodFullName(podFullName string) (string, string, error) {
+	parts := strings.Split(podFullName, "_")
+	if len(parts) != 2 {
+		return "", "", fmt.Errorf("failed to parse the pod full name %q", podFullName)
+	}
+	return parts[0], parts[1], nil
+}