kubeadm: Update the dropin for the kubelet in v1.11

[luxas]

What this PR does / why we need it:
One of the final pieces of kubernetes/kubeadm#851, kubernetes/kubeadm#847 and kubernetes/kubeadm#822

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
(partially)
Fixes kubernetes/kubeadm#822

Special notes for your reviewer: Please check whether this release note makes sense to you.

Release note:

[action required] The structure of the kubelet dropin in the kubeadm deb package has changed significantly.
Instead of hard-coding the parameters for the kubelet in the dropin, a structured configuration file
for the kubelet is used, and is expected to be present in `/var/lib/kubelet/config.yaml`.
For runtime-detected, instance-specific configuration values, a environment file with
dynamically-generated flags at `kubeadm init` or `kubeadm join` run time is used.
Finally, if the user wants to override something specific for the kubelet that can't be done via
the kubeadm Configuration file (which is preferred), they might add flags to the 
`KUBELET_EXTRA_ARGS` environment variable in either `/etc/default/kubelet`
or `/etc/sysconfig/kubelet`, depending on the system you're running on.

@kubernetes/sig-cluster-lifecycle-pr-reviews

[luxas]

/kind feature
/priority critical-urgent
/milestone v1.11
/status approved-for-milestone

[k8s-github-robot]

[MILESTONENOTIFIER] Milestone Pull Request: Up-to-date for process

@luxas @timothysc

Pull Request Labels

• sig/cluster-lifecycle: Pull Request will be escalated to these SIGs if needed.
• priority/critical-urgent: Never automatically move pull request out of a release milestone; continually escalate to contributor and SIG through all available channels.
• kind/feature: New functionality.

Help

• Additional instructions
• Commands for setting labels

[timothysc]

/lgtm
/approve

in the future I think we should de-dupe this
/cc @chuckha

[luxas]

in the future I think we should de-dupe this

I think so too if possible, but there is one small difference I don't know if can be customized easily, /etc/default/kubelet vs /etc/sysconfig/kubelet 🤔

[timothysc]

I think so too if possible, but there is one small difference I don't know if can be customized easily, /etc/default/kubelet vs /etc/sysconfig/kubelet 🤔

build-vars through bazel gen.

[luxas]

Ugh, apparently there is no OWNERS file for build/rpms, although it should equal build/debs OWNERS... @timothysc can you send a PR to fix that please?
Manually overriding in order to get this merged meanwhile

/test pull-kubernetes-e2e-kubeadm-gce
as well

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

Approval requirements bypassed by manually added approval.

This pull-request has been approved by: luxas, timothysc

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:

• build/OWNERS

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

[detiber]

Pardon my ignorance here, but how will this work during upgrades? Once the kubeadm deb is installed the kubelet service will be restarted and pick up this drop in file.

[timothysc]

upgrade will overwrite but drop and env-override on join that the operator will need to address.

upgrades are not seamless which is why @luxas did this PR with it's own action required release note.

[fejta-bot]

/retest
This bot automatically retries jobs that failed/flaked on approved PRs (send feedback to fejta).

Review the full test history for this PR.

Silence the bot with an /lgtm cancel comment for consistent failures.

[k8s-github-robot]

Automatic merge from submit-queue (batch tested with PRs 64009, 64780, 64354, 64727, 63650). If you want to cherry-pick this change to another branch, please follow the instructions here.