Feature DynamicKubeletConfig is deprecated in 1.22 and will not move to GA

[cristicalin]

Flag --dynamic-config-dir has been deprecated, Feature DynamicKubeletConfig is deprecated in 1.22 and will not move to GA. It is planned to be removed from Kubernetes in the version 1.23. Please use alternative ways to update kubelet configuration.

What type of PR is this?
/kind bug

What this PR does / why we need it:
This PR addressed the deprecation of kubelet dynamic configuration in K8S 1.22 and ensures this feature is not accidentally enabled beyond 1.22 which could cause the kubelet to fail to start or worse break kubernetes upgrades.

Which issue(s) this PR fixes:

Fixes #7937

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

Flag --dynamic-config-dir has been deprecated, Feature DynamicKubeletConfig is deprecated in 1.22 and will not move to GA. It is planned to be removed from Kubernetes in the version 1.23. Please use alternative ways to update kubelet configuration.

[k8s-ci-robot]

Hi @cristicalin. Thanks for your PR.

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[champtar]

Should we fail instead of silently removing the flag ?

[cristicalin]

Currently an upgrade attempt fails in an ugly way, see the related issue. Do we have any sanity checks before proceeding where we can implement this check early on?

I have another check in mind with regard to verifying various version compatibilities where we support multiple versions (i.e. calico, cillium and so on). We could add a sanity check task/role early on in kubespray that would prevent running when incompatibilities are found and issue relevant warnings.

[cristicalin]

I answered my own question, we do have settings validation in roles/kubernetes/preinstall/tasks/0020-verify-settings.yml. The last commit adds a check in this validation task to avoid proceeding with changes if dynamic_kubelet_configuration is set to true and kubernetes is 1.22 or above.

/cc @champtar

[floryut]

/ok-to-test
Why commenting the setting in test and not removing it though ?

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: cristicalin, floryut

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[cristicalin]

Why commenting the setting in test and not removing it though ?

To keep it around for historical reasons? I can remove it if you think it's cleaner that way.

[cristicalin]

I removed the commented lines in the tests files instead of just commenting them.

[oomichi]

/lgtm