Add kubelet cgroup driver property

[bmelbourne]

What type of PR is this?
/kind bug

What this PR does / why we need it:
Allow Docker and Kubelet to set the Cgroup Driver to systemd as recommended in the official Kubernetes docs.

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

Which issue(s) this PR fixes:
When attempting to set the Docker container runtime cgroup driver (native.cgroupdriver) to systemd in the Kops YAML manifest.

...
  docker:
    execOpt:
    - native.cgroupdriver=systemd
...

The following Kubelet error is reported during the Kops Kubernetes bootstrapping process.

Sep 07 10:48:58 ip-172-20-62-0 kubelet[8384]: F0907 10:48:58.919376    8384 server.go:274] 
failed to run Kubelet: misconfiguration: kubelet cgroup driver: "cgroupfs" is different from 
docker cgroup driver: "systemd"

Special notes for your reviewer:
Tested using Kops Version 1.19.0-alpha.3 (git-d8b7310c69).

/etc/sysconfig/kubelet

DAEMON_ARGS="--anonymous-auth=false --authentication-token-webhook=true 
--authorization-mode=Webhook --cgroup-driver=systemd --cgroup-root=/ 
--client-ca-file=/srv/kubernetes/ca.crt --cloud-provider=aws --cluster-dns=
100.64.0.10 --cluster-domain=cluster.local --enable-debugging-handlers=true 
--eviction-hard=memory.available<100Mi,nodefs.available<10%,nodefs.inodesFree<5%,imagefs.
available<10%,imagefs.inodesFree<5% --hostname-override=ip-172-20-50-252.
eu-west-2.compute.internal --kubeconfig=/var/lib/kubelet/kubeconfig --network-plugin=cni 
--non-masquerade-cidr=100.64.0.0/10 --pod-infra-container-image=k8s.gcr.io/pause:3.2 
--pod-manifest-path=/etc/kubernetes/manifests --register-schedulable=true 
--register-with-taints=node-role.kubernetes.io/master=:NoSchedule --resolv-conf=
/run/systemd/resolve/resolv.conf --v=2 --volume-plugin-dir=/usr/libexec/kubernetes/
kubelet-plugins/volume/exec/ --cni-bin-dir=/opt/cni/bin/ --cni-conf-dir=/etc/cni/net.d/"
HOME="/root"

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[k8s-ci-robot]

Hi @bmelbourne. 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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[hakman]

Thanks for adding this. Was quite curious to try it myself.
Please run make crds and commit the changes.
/ok-to-test

[hakman]

I think "explicit" is misspelled. Please fix and also squash all commits.

[bmelbourne]

I think "explicit" is misspelled. Please fix and also squash all commits.

I'm following most of the steps outlined here...
https://github.com/kubernetes/community/blob/master/contributors/guide/pull-requests.md#run-local-verifications

But as I'm running on a Windows 10 machine and hence no Docker available, it's leaving me dependent on the outcome of the PR tests for feedback.

...
hack/verify-spelling.sh
/c/Google_Drive/GitHub/kops/hack/verify-shellcheck.sh
Using shellcheck 0.7.1 docker image.
Failed to create shellcheck container with output: 

docker: Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?.
See 'docker run --help'.
Makefile:452: recipe for target 'verify-shellcheck' failed
make: *** [verify-shellcheck] Error 1

Also, I'll squash the commits once all of the tests are passing.

[hakman]

No worries, sometimes it's easier to just wait for automated tests to tell you what's left.
Looks good now. Will wait for the squash and then merge it.

[bmelbourne]

/assign @zetaab

[hakman]

Thanks @bmelbourne .
/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

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

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

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Needs approval from an approver in each of these files:

• OWNERS [hakman]

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[hakman]

/retest

[olemarkus]

It would have been nice with some validation logic here

[hakman]

It would have been nice with some validation logic here

Good idea, can be done in a future PR.