OOM protected docker processes (-900)

pkg/kubelet/container_manager_linux.go

@@ -39,7 +39,8 @@ type containerManagerImpl struct {
 	dockerContainerName string
 
 	// The manager of the resource-only container Docker should be in.
-	manager fs.Manager
+	manager           fs.Manager
+	dockerOomScoreAdj int
 }
 
 var _ containerManager = &containerManagerImpl{}
@@ -55,6 +56,7 @@ func newContainerManager(dockerDaemonContainer string) (containerManager, error)
 				AllowAllDevices: true,
 			},
 		},
+		dockerOomScoreAdj: -900,
 	}, nil
 }
 
@@ -103,6 +105,11 @@ func (cm *containerManagerImpl) ensureDockerInContainer() error {
 				errs = append(errs, fmt.Errorf("failed to move PID %q (in %q) to %q", pid, cont, cm.dockerContainerName))
 			}
 		}
+
+		// Also apply oom_score_adj to processes
+		if err := util.ApplyOomScoreAdj(pid, cm.dockerOomScoreAdj); err != nil {
+			errs = append(errs, fmt.Errorf("failed to apply oom score %q to PID %q", cm.dockerOomScoreAdj, pid))
+		}
 	}
 
 	return errors.NewAggregate(errs)

pkg/kubelet/dockertools/manager.go

@@ -1293,7 +1293,8 @@ func (dm *DockerManager) createPodInfraContainer(pod *api.Pod) (kubeletTypes.Doc
 	if containerInfo.State.Pid == 0 {
 		return "", fmt.Errorf("failed to get init PID for Docker pod infra container %q", string(id))
 	}
-	return id, util.ApplyOomScoreAdj(containerInfo.State.Pid, podOomScoreAdj)
+	util.ApplyOomScoreAdj(containerInfo.State.Pid, podOomScoreAdj)
+	return id, nil
 }
 
 // TODO(vmarmol): This will soon be made non-public when its only use is internal.

pkg/util/util.go

@@ -214,8 +214,13 @@ func ApplyOomScoreAdj(pid int, value int) error {
 		pidStr = strconv.Itoa(pid)
 	}
 
-	if err := ioutil.WriteFile(path.Join("/proc", pidStr, "oom_score_adj"), []byte(strconv.Itoa(value)), 0700); err != nil {
-		fmt.Errorf("failed to set oom_score_adj to %d: %v", value, err)
+	oom_value, err := ioutil.ReadFile(path.Join("/proc", pidStr, "oom_score_adj"))
+	if err != nil {
+		return fmt.Errorf("failed to read oom_score_adj: %v", err)
+	} else if string(oom_value) != strconv.Itoa(value) {
+		if err := ioutil.WriteFile(path.Join("/proc", pidStr, "oom_score_adj"), []byte(strconv.Itoa(value)), 0700); err != nil {
+			return fmt.Errorf("failed to set oom_score_adj to %d: %v", value, err)
+		}
 	}
 
 	return nil