fix kubelet ignoring docker daemon in container feature

pkg/kubelet/cm/container_manager_linux.go

@@ -358,6 +358,7 @@ func (cm *containerManagerImpl) setupNode() error {
 			systemContainers = append(systemContainers, cont)
 		} else {
 			cm.periodicTasks = append(cm.periodicTasks, func() {
+				glog.V(10).Infof("Adding docker daemon periodic tasks")
 				if err := ensureDockerInContainer(dockerVersion, qos.DockerOOMScoreAdj, nil); err != nil {
 					glog.Error(err)
 					return
@@ -524,16 +525,18 @@ func (cm *containerManagerImpl) SystemCgroupsLimit() api.ResourceList {
 }
 
 func isProcessRunningInHost(pid int) (bool, error) {
-	// Get init mount namespace. Mount namespace is unique for all containers.
-	initMntNs, err := os.Readlink("/proc/1/ns/mnt")
+	// Get init pid namespace.
+	initPidNs, err := os.Readlink("/proc/1/ns/pid")
 	if err != nil {
-		return false, fmt.Errorf("failed to find mount namespace of init process")
+		return false, fmt.Errorf("failed to find pid namespace of init process")
 	}
-	processMntNs, err := os.Readlink(fmt.Sprintf("/proc/%d/ns/mnt", pid))
+	glog.V(10).Infof("init pid ns is %q", initPidNs)
+	processPidNs, err := os.Readlink(fmt.Sprintf("/proc/%d/ns/pid", pid))
 	if err != nil {
-		return false, fmt.Errorf("failed to find mount namespace of process %q", pid)
+		return false, fmt.Errorf("failed to find pid namespace of process %q", pid)
 	}
-	return initMntNs == processMntNs, nil
+	glog.V(10).Infof("Pid %d pid ns is %q", pid, processPidNs)
+	return initPidNs == processPidNs, nil
 }
 
 func getPidFromPidFile(pidFile string) (int, error) {
@@ -575,7 +578,6 @@ func ensureDockerInContainer(dockerVersion semver.Version, oomScoreAdj int, mana
 	if dockerVersion.GTE(containerdVersion) {
 		dockerProcs = append(dockerProcs, process{containerdProcessName, containerdPidFile})
 	}
-
 	var errs []error
 	for _, proc := range dockerProcs {
 		pids, err := getPidsForProcess(proc.name, proc.file)
@@ -600,25 +602,28 @@ func ensureProcessInContainerWithOOMScore(pid int, oomScoreAdj int, manager *fs.
 		return err
 	} else if !runningInHost {
 		// Process is running inside a container. Don't touch that.
-		glog.V(2).Infof("pid %d is running in the host namespaces", pid)
+		glog.V(2).Infof("pid %d is not running in the host namespaces", pid)
 		return nil
 	}
 
 	var errs []error
+	if manager != nil {
 		cont, err := getContainer(pid)
 		if err != nil {
 			errs = append(errs, fmt.Errorf("failed to find container of PID %d: %v", pid, err))
 		}
 
-	if manager != nil && cont != manager.Cgroups.Name {
+		if cont != manager.Cgroups.Name {
 			err = manager.Apply(pid)
 			if err != nil {
 				errs = append(errs, fmt.Errorf("failed to move PID %d (in %q) to %q: %v", pid, cont, manager.Cgroups.Name, err))
 			}
 		}
+	}
 
 	// Also apply oom-score-adj to processes
 	oomAdjuster := oom.NewOOMAdjuster()
+	glog.V(5).Infof("attempting to apply oom_score_adj of %d to pid %d", oomScoreAdj, pid)
 	if err := oomAdjuster.ApplyOOMScoreAdj(pid, oomScoreAdj); err != nil {
 		glog.V(3).Infof("Failed to apply oom_score_adj %d for pid %d: %v", oomScoreAdj, pid, err)
 		errs = append(errs, fmt.Errorf("failed to apply oom score %d to PID %d: %v", oomScoreAdj, pid, err))