crio: use system default for storage driver by default

[hafe]

After host reboot kubelet and crio goes into a loop and no container is started.

storage_driver in crio.conf overrides system defaults in etc/containers/storage.conf

/etc/containers/storage.conf is installed by package containers-common dependency
installed from cri-o (centos7) and contains "overlay".

Hosts already configured with overlay2 should be reconfigured and the
/var/lib/containers content removed.

What type of PR is this?

Uncomment only one /kind <> line, hit enter to put that in a new line, and remove leading whitespaces from that line:

/kind api-change
/kind bug
/kind cleanup
/kind design
/kind documentation
/kind failing-test
/kind feature
/kind flake

What this PR does / why we need it:

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

[k8s-ci-robot]

Hi @hafe. Thanks for your PR.

I'm waiting for a kubernetes-sigs 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.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

I understand the commands that are listed here.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[floryut]

/ok-to-test

[floryut]

Ok scratch my comment, I guess the point here is not to force the driver but use the default one from the global conf

[hafe]

I agree it is confusing but as you said here was that Kubespray created a conflicting config that seemed work but created chaos!

I also remember that overlay2 should be used. Somewhere (crio?) I read that nowadays they even are the same in the kernel...

[floryut]

Don't know if @spaced can take a look ?
But looks good to me.

[Miouge1]

/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: hafe, Miouge1

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [Miouge1]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[EppO]

overlay2 should be the default, not overlay. overlay2 is available on all distros kubespray supports AFAIK, and is more efficient than overlay according to docker:

Note: If you use OverlayFS, use the overlay2 driver rather than the overlay driver, because it is more efficient in terms of inode utilization. To use the new driver, you need version 4.0 or higher of the Linux kernel, or RHEL or CentOS using version 3.10.0-514 and above.

that means kubespray should manage the content of etc/containers/storage.conf I guess.

[hafe]

Openshift uses overlay and I think I have seen comments that they are the same nowadays

[hafe]

But this patch is about not creating a conflicting configuration

[hafe]

Checking with the crio community

[hafe]

Community answer is that there's no overlay2 in podman/crio, just overlay. They renamed overlay2 to overlay

[hafe]

cri-o/cri-o#4175

[haircommander]

LGTM, overlay==overlay2 in crio world, but there are some strange things that happen when /etc/containers/storage.conf and /etc/crio/crio.conf are out of sync. Defaulting to overlay all the time mitigates this (while the crio team looks at why overlay2 confuses it).

[floryut]

/lgtm