Ensure that init containers are preserved during pruning

pkg/kubelet/dockertools/manager.go

@@ -2095,7 +2095,7 @@ func (dm *DockerManager) tryContainerStart(container *api.Container, pod *api.Po
 // of outstanding init containers still present. This reduces load on the container garbage collector
 // by only preserving the most recent terminated init container.
 func (dm *DockerManager) pruneInitContainersBeforeStart(pod *api.Pod, podStatus *kubecontainer.PodStatus, initContainersToKeep map[kubecontainer.DockerID]int) {
-	// only the last execution of an init container should be preserved, and only preserve it if it is in the
+	// only the last execution of each init container should be preserved, and only preserve it if it is in the
 	// list of init containers to keep.
 	initContainerNames := sets.NewString()
 	for _, container := range pod.Spec.InitContainers {
@@ -2104,11 +2104,11 @@ func (dm *DockerManager) pruneInitContainersBeforeStart(pod *api.Pod, podStatus
 	for name := range initContainerNames {
 		count := 0
 		for _, status := range podStatus.ContainerStatuses {
-			if !initContainerNames.Has(status.Name) || status.State != kubecontainer.ContainerStateExited {
+			if status.Name != name || !initContainerNames.Has(status.Name) || status.State != kubecontainer.ContainerStateExited {
 				continue
 			}
 			count++
-			// keep the first init container we see
+			// keep the first init container for this name
 			if count == 1 {
 				continue
 			}
@@ -2125,7 +2125,7 @@ func (dm *DockerManager) pruneInitContainersBeforeStart(pod *api.Pod, podStatus
 					count--
 					continue
 				}
-				utilruntime.HandleError(fmt.Errorf("failed to remove pod init container %q: %v; Skipping pod %q", name, err, format.Pod(pod)))
+				utilruntime.HandleError(fmt.Errorf("failed to remove pod init container %q: %v; Skipping pod %q", status.Name, err, format.Pod(pod)))
 				// TODO: report serious errors
 				continue
 			}

pkg/kubelet/dockertools/manager_test.go

@@ -1892,3 +1892,37 @@ func TestGetPodStatusNoSuchContainer(t *testing.T) {
 		"create", "start", "inspect_container",
 	})
 }
+
+func TestPruneInitContainers(t *testing.T) {
+	dm, fake := newTestDockerManager()
+	pod := &api.Pod{
+		Spec: api.PodSpec{
+			InitContainers: []api.Container{
+				{Name: "init1"},
+				{Name: "init2"},
+			},
+		},
+	}
+	status := &kubecontainer.PodStatus{
+		ContainerStatuses: []*kubecontainer.ContainerStatus{
+			{Name: "init2", ID: kubecontainer.ContainerID{ID: "init2-new-1"}, State: kubecontainer.ContainerStateExited},
+			{Name: "init1", ID: kubecontainer.ContainerID{ID: "init1-new-1"}, State: kubecontainer.ContainerStateExited},
+			{Name: "init1", ID: kubecontainer.ContainerID{ID: "init1-new-2"}, State: kubecontainer.ContainerStateExited},
+			{Name: "init1", ID: kubecontainer.ContainerID{ID: "init1-old-1"}, State: kubecontainer.ContainerStateExited},
+			{Name: "init2", ID: kubecontainer.ContainerID{ID: "init2-old-1"}, State: kubecontainer.ContainerStateExited},
+		},
+	}
+	fake.ExitedContainerList = []dockertypes.Container{
+		{ID: "init1-new-1"},
+		{ID: "init1-new-2"},
+		{ID: "init1-old-1"},
+		{ID: "init2-new-1"},
+		{ID: "init2-old-1"},
+	}
+	keep := map[kubecontainer.DockerID]int{}
+	dm.pruneInitContainersBeforeStart(pod, status, keep)
+	sort.Sort(sort.StringSlice(fake.Removed))
+	if !reflect.DeepEqual([]string{"init1-new-2", "init1-old-1", "init2-old-1"}, fake.Removed) {
+		t.Fatal(fake.Removed)
+	}
+}