Files
kubernetes/cmd
Kubernetes Submit Queue b38f1b901f Merge pull request #59898 from Random-Liu/add-log-rotation
Automatic merge from submit-queue (batch tested with PRs 60214, 58762, 59898, 59897, 60204). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Add CRI container log rotation support

Fixes https://github.com/kubernetes/kubernetes/issues/58823.

This PR:
1) Added `pkg/kubelet/logs/container_log_manager.go` which manages and rotates container logs.
2) Added a feature gate `CRIContainerLogRotation` to enable the alpha feature. And 2 kubelet flags `--container-log-max-size` and `--container-log-max-files` to configure the rotation behavior.
3) Added unit test and node e2e test for container log rotation.

Note that:
1) Container log manager only starts when the container runtime is `remote` (not docker), because we can't implement `ReopenContainerLog` for docker.
2) Rotated logs are compressed with `gzip`.
2) The latest rotated log is not compressed. Because fluentd may still be reading the file right after rotation.
3) `kubectl logs` still doesn't support log rotation. This is not a regression anyway, it doesn't support log rotation for docker log today. We'll probably fix this in the future. (Issue: https://github.com/kubernetes/kubernetes/issues/59902)

An example of container log directory with `--container-log-max-files=3`:
```console
$ ls -al /var/log/pods/57146449-11ec-11e8-90e1-42010af00002
total 592
drwxr-xr-x 2 root root   4096 Feb 15 01:07 .
drwxr-xr-x 3 root root  12288 Feb 15 01:06 ..
-rw-r----- 1 root root 176870 Feb 15 01:07 log-container_0.log
-rw-r--r-- 1 root root  40239 Feb 15 01:07 log-container_0.log.20180215-010737.gz
-rw-r----- 1 root root 365996 Feb 15 01:07 log-container_0.log.20180215-010747
```

/assign @mtaufen for the config change.
/assign @dashpole @crassirostris for the log change.
/assign @feiskyer for CRI related change.
/cc @yujuhong @feiskyer @abhi @mikebrow @mrunalp @runcom 
/cc @kubernetes/sig-node-pr-reviews @kubernetes/sig-instrumentation-pr-reviews 

**Release note**:

```release-note
[Alpha] Kubelet now supports container log rotation for container runtime which implements CRI(container runtime interface).
The feature can be enabled with feature gate `CRIContainerLogRotation`.
The flags `--container-log-max-size` and `--container-log-max-files` can be used to configure the rotation behavior.
```
2018-02-22 22:02:37 -08:00
..
2018-02-15 12:01:00 -08:00