kubelet: Introduce PodInfraContainerChanged().

This functions computes in ahead whether we need to restart the pod
infra container.

pkg/kubelet/dockertools/docker.go

@@ -40,8 +40,9 @@ import (
 )
 
 const (
-	PodInfraContainerName = leaky.PodInfraContainerName
-	DockerPrefix          = "docker://"
+	PodInfraContainerName  = leaky.PodInfraContainerName
+	DockerPrefix           = "docker://"
+	PodInfraContainerImage = "gcr.io/google_containers/pause:0.8.0"
 )
 
 const (

pkg/kubelet/dockertools/manager.go

@@ -452,3 +452,40 @@ func makeCapabilites(capAdd []api.CapabilityType, capDrop []api.CapabilityType)
 	}
 	return addCaps, dropCaps
 }
+
+// PodInfraContainer returns true if the pod infra container has changed.
+func (self *DockerManager) PodInfraContainerChanged(pod *api.Pod, podInfraContainer *kubecontainer.Container) (bool, error) {
+	// Use host networking if specified and allowed.
+	networkMode := ""
+	var ports []api.ContainerPort
+
+	dockerPodInfraContainer, err := self.client.InspectContainer(string(podInfraContainer.ID))
+	if err != nil {
+		return false, err
+	}
+
+	// Check network mode.
+	if dockerPodInfraContainer.HostConfig != nil {
+		networkMode = dockerPodInfraContainer.HostConfig.NetworkMode
+	}
+	if pod.Spec.HostNetwork && networkMode != "host" {
+		return true, nil
+	} else {
+		// Docker only exports ports from the pod infra container.  Let's
+		// collect all of the relevant ports and export them.
+		for _, container := range pod.Spec.Containers {
+			ports = append(ports, container.Ports...)
+		}
+	}
+	container := &api.Container{
+		Name:  PodInfraContainerName,
+		Image: PodInfraContainerImage,
+		Ports: ports,
+	}
+
+	expectedHash := HashContainer(container)
+	if podInfraContainer.Hash != expectedHash {
+		return true, nil
+	}
+	return false, nil
+}

pkg/kubelet/kubelet.go

@@ -854,10 +854,6 @@ func (kl *Kubelet) killContainerByID(ID string) error {
 	return err
 }
 
-const (
-	PodInfraContainerImage = "gcr.io/google_containers/pause:0.8.0"
-)
-
 // Determined whether the specified pod is allowed to use host networking
 func allowHostNetwork(pod *api.Pod) (bool, error) {
 	podSource, err := getPodSource(pod)
@@ -1116,8 +1112,15 @@ func (kl *Kubelet) computePodContainerChanges(pod *api.Pod, runningPod kubeconta
 	podInfraContainer := runningPod.FindContainerByName(dockertools.PodInfraContainerName)
 	if podInfraContainer != nil {
 		glog.V(4).Infof("Found infra pod for %q", podFullName)
-		podInfraContainerID = dockertools.DockerID(podInfraContainer.ID)
-		containersToKeep[podInfraContainerID] = -1
+		changed, err := kl.containerManager.PodInfraContainerChanged(pod, podInfraContainer)
+		if err != nil {
+			return podContainerChangesSpec{}, err
+		}
+		if !changed {
+			glog.V(4).Infof("Infra pod is good, keeps it %q", podFullName)
+			podInfraContainerID = dockertools.DockerID(podInfraContainer.ID)
+			containersToKeep[podInfraContainerID] = -1
+		}
 
 	} else {
 		glog.V(2).Infof("No Infra Container for %q found. All containers will be restarted.", podFullName)
@@ -1163,21 +1166,10 @@ func (kl *Kubelet) computePodContainerChanges(pod *api.Pod, runningPod kubeconta
 						continue
 					}
 					glog.Infof("pod %q container %q is unhealthy (probe result: %v). Container will be killed and re-created.", podFullName, container.Name, result)
-					containersToStart[index] = empty{}
 				} else {
 					glog.Infof("pod %q container %q hash changed (%d vs %d). Pod will be killed and re-created.", podFullName, container.Name, hash, expectedHash)
-					createPodInfraContainer = true
-					delete(containersToKeep, podInfraContainerID)
-					// If we are to restart Infra Container then we move containersToKeep into containersToStart
-					// if RestartPolicy allows restarting failed containers.
-					if pod.Spec.RestartPolicy != api.RestartPolicyNever {
-						for _, v := range containersToKeep {
-							containersToStart[v] = empty{}
-						}
-					}
-					containersToStart[index] = empty{}
-					containersToKeep = make(map[dockertools.DockerID]int)
 				}
+				containersToStart[index] = empty{}
 			} else { // createPodInfraContainer == true and Container exists
 				// If we're creating infra containere everything will be killed anyway
 				// If RestartPolicy is Always or OnFailure we restart containers that were running before we

pkg/kubelet/kubelet_test.go

@@ -455,6 +455,18 @@ func TestSyncPodsDoesNothing(t *testing.T) {
 			ID:    "9876",
 		},
 	}
+	fakeDocker.ContainerMap = map[string]*docker.Container{
+		"1234": {
+			ID:         "1234",
+			HostConfig: &docker.HostConfig{},
+			Config:     &docker.Config{},
+		},
+		"9876": {
+			ID:         "9876",
+			HostConfig: &docker.HostConfig{},
+			Config:     &docker.Config{},
+		},
+	}
 	pods := []api.Pod{
 		{
 			ObjectMeta: api.ObjectMeta{