Merge pull request kubernetes#36664 from yujuhong/fix_comments

Automatic merge from submit-queue

dockershim: clean up comments

Author: Kubernetes Submit Queue

pkg/kubelet/dockershim/docker_container.go

@@ -79,7 +79,8 @@ func (ds *dockerService) ListContainers(filter *runtimeApi.ContainerFilter) ([]*
 }
 
 // CreateContainer creates a new container in the given PodSandbox
-// Note: docker doesn't use LogPath yet.
+// Docker cannot store the log to an arbitrary location (yet), so we create an
+// symlink at LogPath, linking to the actual path of the log.
 // TODO: check if the default values returned by the runtime API are ok.
 func (ds *dockerService) CreateContainer(podSandboxID string, config *runtimeApi.ContainerConfig, sandboxConfig *runtimeApi.PodSandboxConfig) (string, error) {
 	if config == nil {
@@ -140,7 +141,7 @@ func (ds *dockerService) CreateContainer(podSandboxID string, config *runtimeApi
 		if rOpts != nil {
 			hc.Resources = dockercontainer.Resources{
 				Memory:     rOpts.GetMemoryLimitInBytes(),
-				MemorySwap: -1, // Always disable memory swap.
+				MemorySwap: -1,
 				CPUShares:  rOpts.GetCpuShares(),
 				CPUQuota:   rOpts.GetCpuQuota(),
 				CPUPeriod:  rOpts.GetCpuPeriod(),
@@ -229,10 +230,10 @@ func (ds *dockerService) StartContainer(containerID string) error {
 	}
 	// Create container log symlink.
 	if err := ds.createContainerLogSymlink(containerID); err != nil {
-		// Do not stop the container if fail to create symlink, because:
-		// 1. This is not a critical failure.
-		// 2. We don't have enough information to properly stop container here.
-		// Kubelet will surface this error to user with event.
+		// Do not stop the container if we failed to create symlink because:
+		//   1. This is not a critical failure.
+		//   2. We don't have enough information to properly stop container here.
+		// Kubelet will surface this error to user via an event.
 		return err
 	}
 	return nil
@@ -248,7 +249,7 @@ func (ds *dockerService) StopContainer(containerID string, timeout int64) error
 func (ds *dockerService) RemoveContainer(containerID string) error {
 	// Ideally, log lifecycle should be independent of container lifecycle.
 	// However, docker will remove container log after container is removed,
-	// we can't prevent that now, so we also cleanup the symlink here.
+	// we can't prevent that now, so we also clean up the symlink here.
 	err := ds.removeContainerLogSymlink(containerID)
 	if err != nil {
 		return err
@@ -279,7 +280,7 @@ func getContainerTimestamps(r *dockertypes.ContainerJSON) (time.Time, time.Time,
 	return createdAt, startedAt, finishedAt, nil
 }
 
-// ContainerStatus returns the container status.
+// ContainerStatus inspects the docker container and returns the status.
 func (ds *dockerService) ContainerStatus(containerID string) (*runtimeApi.ContainerStatus, error) {
 	r, err := ds.client.InspectContainer(containerID)
 	if err != nil {
@@ -292,7 +293,7 @@ func (ds *dockerService) ContainerStatus(containerID string) (*runtimeApi.Contai
 		return nil, fmt.Errorf("failed to parse timestamp for container %q: %v", containerID, err)
 	}
 
-	// Convert the image id to pullable id.
+	// Convert the image id to a pullable id.
 	ir, err := ds.client.InspectImageByID(r.Image)
 	if err != nil {
 		return nil, fmt.Errorf("unable to inspect docker image %q while inspecting docker container %q: %v", r.Image, containerID, err)

pkg/kubelet/dockershim/docker_sandbox.go

@@ -368,7 +368,7 @@ func sharesHostNetwork(container *dockertypes.ContainerJSON) bool {
 
 func setSandboxResources(hc *dockercontainer.HostConfig) {
 	hc.Resources = dockercontainer.Resources{
-		MemorySwap: -1, // Always disable memory swap.
+		MemorySwap: -1,
 		CPUShares:  defaultSandboxCPUshares,
 		// Use docker's default cpu quota/period.
 	}