Merge pull request #35348 from Random-Liu/kuberuntime-container-logs

Automatic merge from submit-queue

CRI: Add kuberuntime container logs

Based on https://github.com/kubernetes/kubernetes/pull/34858.

The first 2 commits are from #34858. And the last 2 commits are new.

This PR added kuberuntime container logs support and add unit test for it.

I've tested all the functions manually, and I'll send another PR to write a node e2e test for container log.

**_Notice: current implementation doesn't support log rotation**_, which means that:
- It will not retrieve logs in rotated log file.
- If log rotation happens when following the log:
  - If the rotation is using create mode, we'll still follow the old file.
  - If the rotation is using copytruncate, we'll be reading at the original position and get nothing.

To solve these issues, kubelet needs to rotate the log itself, or at least kubelet should be able to control the the behavior of log rotator. These are doable but out of the scope of 1.5 and will be addressed in future release.

@yujuhong @feiskyer @yifan-gu 
/cc @kubernetes/sig-node

pkg/kubelet/kuberuntime/helpers.go

@@ -207,6 +207,11 @@ func buildContainerLogsPath(containerName string, restartCount int) string {
 	return fmt.Sprintf("%s_%d.log", containerName, restartCount)
 }
 
+// buildFullContainerLogsPath builds absolute log path for container.
+func buildFullContainerLogsPath(podUID types.UID, containerName string, restartCount int) string {
+	return filepath.Join(buildPodLogsDirectory(podUID), buildContainerLogsPath(containerName, restartCount))
+}
+
 // buildPodLogsDirectory builds absolute log directory path for a pod sandbox.
 func buildPodLogsDirectory(podUID types.UID) string {
 	return filepath.Join(podLogsRootDirectory, string(podUID))