kubeadm: add support for patches in v1beta3; deprecate --experimental-patches

[neolit123]

What this PR does / why we need it:

The feature of "patches" in kubeadm has been in Alpha for a few
releases. It has not received major bug reports from users.
Deprecate the --experimental-patches flag and add --patches.

Both flags are allowed to be mixed with --config.

Add {Init|Join}Configuration.Patches, which is a structure that
contains patch related options. Currently it only has the "Directory"
field which is the same option as the existing --experimental-patches
flag.

The flags --[experimental-]patches value override this value
if both a flag and config is passed during "init" or "join".

Which issue(s) this PR fixes:

xref kubernetes/kubeadm#2046
xref kubernetes/kubeadm#1796

Special notes for your reviewer:

Does this PR introduce a user-facing change?

ACTION REQUIRED: the flag --experimental-patches is now deprecated and will be removed in a future release. You can migrate to using the new flag --patches. Add a new field {Init|Join}Configuration.patches.directory that can be used for the same purpose. For "init" and "join" it is now recommended that you migrate to configure patches via {Init|Join}Configuration.patches.directory. For the time being, these flags can be mixed with --config, but that might change in the future. On a command line, the last *patches flag takes precedence over previous flags and the value in config. "kubeadm upgrade" --patches will continue to be the only available option, since "upgrade" does not support a configuration file yet.

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

- [KEP]: https://github.com/kubernetes/enhancements/tree/master/keps/sig-cluster-lifecycle/kubeadm/1739-customization-with-patches
- [KEP]: https://github.com/kubernetes/enhancements/tree/master/keps/sig-cluster-lifecycle/kubeadm/970-kubeadm-config

[neolit123]

/kind feature
/priority important-soon
/triage accepted

/cc @fabriziopandini

[neolit123]

/hold for review

[pacoxu]

Does ExperimentalPatches override Patches here?
https://github.com/kubernetes/kubernetes/pull/103063/files#diff-40e2eaae5e3828005feeb02733c99a5f90e56a43e249388ee94a893c2141cf42R104

I cannot leave a message inline(github 500😓).

[neolit123]

Does ExperimentalPatches override Patches here?
https://github.com/kubernetes/kubernetes/pull/103063/files#diff-40e2eaae5e3828005feeb02733c99a5f90e56a43e249388ee94a893c2141cf42R104

I cannot leave a message inline(github 500).

no, basically the order of adding flags does not matter in the code. it matters on the command line.
if both --foo=x --bar=y are passed, and both flags write to the same Go variable, the value of the last flag on the command line --bar will be used. this is mentioned in the release note.

[pacoxu]

/lgtm

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: neolit123, pacoxu

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[neolit123]

/cc @SataQiu @pacoxu

i think @fabriziopandini might be on PTO until next week. the 8th of July is code freeze and we should get this merged before then. do you have any more comments here?

[pacoxu]

According to kubernetes/kubeadm#2046,

• add --patches
• mark --experimental-patches as deprecated
• disallow mixture of --patches and --config
• add Init|JoinConfiguration.patches.directory to v1beta3

disallow mixture of --patches and --config is not implemented in this PR. However, it can be fixed standalone if needed.
/lgtm

[neolit123]

Indeed, disallowing the mixture is missing. I was debating whether it should be done or not in 1.22. It is a bit strange if we disallow it right away. Users might first want to migrate to --patches instead of config. But maybe they can just migrate to config and disallowing the mixture is fine.

…

On Jun 30, 2021 11:41, "Paco Xu" ***@***.***> wrote: According to kubernetes/kubeadm#2046 <kubernetes/kubeadm#2046>, - add --patches - mark --experimental-patches as deprecated - disallow mixture of --patches and --config - add Init|JoinConfiguration.patches.directory to v1beta3 disallow mixture of --patches and --config is not implemented in this PR. However, it can be fixed standalone if needed. /lgtm — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#103063 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AACRATDFJUWNXIMH4CNRB7TTVLKEJANCNFSM47CGSKMQ> .

[pacoxu]

We may disallow it in 1.23 for compatibility.

LGTM then.

[pacoxu]

/hold cancel
/retest

[pacoxu]

/retest