Don't flood the status manager with updates from multi-container pods

pkg/kubelet/dockertools/manager.go

@@ -25,6 +25,7 @@ import (
 	"os"
 	"os/exec"
 	"path"
+	"sort"
 	"strconv"
 	"strings"
 	"sync"
@@ -470,7 +471,9 @@ func (dm *DockerManager) GetPodStatus(pod *api.Pod) (*api.PodStatus, error) {
 		}
 		podStatus.ContainerStatuses = append(podStatus.ContainerStatuses, *status)
 	}
-
+	// TODO: Move this to a custom equals method on the pod status. A container manager
+	// shouldn't have to guarantee order.
+	sort.Sort(kubeletTypes.SortedContainerStatuses(podStatus.ContainerStatuses))
 	return &podStatus, nil
 }
 

pkg/kubelet/dockertools/manager_test.go

@@ -1992,3 +1992,61 @@ func TestSyncPodWithTerminationLog(t *testing.T) {
 		t.Errorf("Unexpected container path: %s", parts[1])
 	}
 }
+
+func TestGetPodStatusSortedContainers(t *testing.T) {
+	dm, fakeDocker := newTestDockerManager()
+	dockerInspect := map[string]*docker.Container{}
+	dockerList := []docker.APIContainers{}
+	specContainerList := []api.Container{}
+	expectedOrder := []string{}
+
+	numContainers := 10
+	podName := "foo"
+	podNs := "test"
+	podUID := "uid1"
+	fakeConfig := &docker.Config{
+		Image: "some:latest",
+	}
+
+	for i := 0; i < numContainers; i++ {
+		id := fmt.Sprintf("%v", i)
+		containerName := fmt.Sprintf("%vcontainer", id)
+		expectedOrder = append(expectedOrder, containerName)
+		dockerInspect[id] = &docker.Container{
+			ID:     id,
+			Name:   containerName,
+			Config: fakeConfig,
+			Image:  fmt.Sprintf("%vimageid", id),
+		}
+		dockerList = append(dockerList, docker.APIContainers{
+			ID:    id,
+			Names: []string{fmt.Sprintf("/k8s_%v_%v_%v_%v_42", containerName, podName, podNs, podUID)},
+		})
+		specContainerList = append(specContainerList, api.Container{Name: containerName})
+	}
+
+	fakeDocker.ContainerMap = dockerInspect
+	fakeDocker.ContainerList = dockerList
+	fakeDocker.ClearCalls()
+	pod := &api.Pod{
+		ObjectMeta: api.ObjectMeta{
+			UID:       types.UID(podUID),
+			Name:      podName,
+			Namespace: podNs,
+		},
+		Spec: api.PodSpec{
+			Containers: specContainerList,
+		},
+	}
+	for i := 0; i < 5; i++ {
+		status, err := dm.GetPodStatus(pod)
+		if err != nil {
+			t.Fatalf("unexpected error %v", err)
+		}
+		for i, c := range status.ContainerStatuses {
+			if expectedOrder[i] != c.Name {
+				t.Fatalf("Container status not sorted, expected %v at index %d, but found %v", expectedOrder[i], i, c.Name)
+			}
+		}
+	}
+}

pkg/kubelet/types/types.go

@@ -19,8 +19,12 @@ package types
 import (
 	"net/http"
 	"time"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
 )
 
+// TODO: Reconcile custom types in kubelet/types and this subpackage
+
 // DockerID is an ID of docker container. It is a type to make it clear when we're working with docker container Ids
 type DockerID string
 
@@ -56,3 +60,13 @@ func (t *Timestamp) Get() time.Time {
 func (t *Timestamp) GetString() string {
 	return t.time.Format(time.RFC3339Nano)
 }
+
+// A type to help sort container statuses based on container names.
+type SortedContainerStatuses []api.ContainerStatus
+
+func (s SortedContainerStatuses) Len() int      { return len(s) }
+func (s SortedContainerStatuses) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
+
+func (s SortedContainerStatuses) Less(i, j int) bool {
+	return s[i].Name < s[j].Name
+}