Docker: Set Cgroup driver by default to systemd

[bmelbourne]

What type of PR is this?
/kind feature

What this PR does / why we need it:
This change is required to align with the official Kubernetes recommendation to use systemd as the Docker Cgroup driver for both the container runtime and kubelet to stabilize the allocation of resources to processes.

https://kubernetes.io/docs/setup/production-environment/container-runtimes/#cgroup-drivers

Which issue(s) this PR fixes:
Fixes #5134

Special notes for your reviewer:
Before working on the user documentation, I'm seeking initial feedback on the implementation.

I also believe that we should just document and advise user's of lnykryn/systemd-rhel#266 and ensure responsibility of addressing Linux OS issues, such as dbus, systemd, etc continues to be with the DevOps / Platform Engineers and the cloud providers via prebuilt images, AMIs, etc.

Whilst it's important to ensure the relevant OS packages are installed prior to deploying Kubespray, by trying to mitigate every possible Linux OS issue would result in over-engineering the solution, which may introduce unknown consequences and constraints for our users.

Does this PR introduce a user-facing change?:

Docker: Set cgroup driver by default to systemd

[k8s-ci-robot]

Hi @bmelbourne. 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.

[bmelbourne]

/assign @chadswen

[Miouge1]

@bmelbourne it looks like this PR is mixing some changes around webhooks as well? maybe those things should be split?

[bmelbourne]

@bmelbourne it looks like this PR is mixing some changes around webhooks as well? maybe those things should be split?

@Miouge1
Those are not my changes...they have been included as part of rebase merge somehow.

I've been asked on a regular basis to do this before the PR will be reviewed and this appears to be the consequence??

$ git pull --rebase upstream master

If this is the incorrect approach, just let me know how the rebase should be achieved as I've not been able to find anything in the docs. I found the command from the CI test jobs.

FYI there is a drop-down at the top-left of the Files changed page where you can filter just on my single commit.

Maybe the approach should be as follows to avoid replaying all commits on this branch?

$ git checkout master
$ git fetch upstream
$ git rebase upstream/master
$ git push origin master
$ git checkout set-docker-cgroup-driver-systemd
$ git pull origin master

[bmelbourne]

/reopen

[k8s-ci-robot]

@bmelbourne: Reopened this PR.

In response to this:

/reopen

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.

[Miouge1]

/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

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

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[floryut]

No reason not to merge this, nice 👍
/lgtm