disable aufs module

[lizhuqi]

What type of PR is this?

/kind bug

What this PR does / why we need it:

This PR is to disable AUFS module which is no longer used by docker.

AUFSUmountHung kernel error slows down the node and caused timeout for other processes.

We've confirmed that docker is using overlay2 and containerd is using overlay so it is safe to disable AUFS.

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?

None

disable aufs module for gce clusters

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

[k8s-ci-robot]

@lizhuqi: This issue is currently awaiting triage.

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[k8s-ci-robot]

Hi @lizhuqi. Thanks for your PR.

I'm waiting for a kubernetes member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[cheftako]

/ok-to-test

[cheftako]

/test pull-kubernetes-e2e-gce-100-performance

[lizhuqi]

See some error in containerd log:
msg="skip loading plugin "io.containerd.snapshotter.v1.aufs"..." error="aufs is not supported (modprobe aufs failed: exit status 1 "modprobe: FATAL: Module aufs not found in directory /lib/modules/5.4.129+\n"): skip plugin" type=io.containerd.snapshotter.v1
time="2021-07-22T00:20:42.322087568Z"

Need to check why performance test tries to load io.containerd.snapshotter.v1.aufs

containrd snapshotter should use overlay instead of aufs.

[lizhuqi]

The test was testing AUFS Snapshotter for containerd. I think we can enable the aufs module in the test.

[lizhuqi]

Confirmed that overlayfs is the default snapshotter for containerd
The snapshotter can be configured via containerd config - /etc/containerd/config.toml
https://github.com/containerd/containerd/blob/main/docs/cri/config.md

[lizhuqi]

just compared the log with a successful run. This error also shows in the successful run. So failed to load io.containerd.snapshotter.v1 is okay. I think maybe I shall check the module is available or not before I tried to disable it. Will add a check and try again.

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: cheftako, lizhuqi

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• cluster/gce/gci/OWNERS [cheftako]

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[cheftako]

/priority important-soon

[cheftako]

aufs seems to be a common cause of flaky tests.
It has been linked to extended timeout periods for the kubelet during testing.

[cheftako]

/cc @liggitt @jpbetz

[saschagrunert]

Do we need to cherry-pick this PR into release-1.22?

[cheftako]

Do we need to cherry-pick this PR into release-1.22?

Yes. #103926