feat: add support for server-side apply

[sathieu]

Fixes: #2267
Requires: argoproj/gitops-engine#363

Checklist:

• Either (a) I've created an enhancement proposal and discussed it with the community, (b) this is a bug fix, or (c) this does not need to be in the release notes.
• The title of the PR states what changed and the related issues number (used for the release note).
• I've included "Closes [ISSUE #]" or "Fixes [ISSUE #]" in the description to automatically close the associated issue.
• I've updated both the CLI and UI to expose my feature, or I plan to submit a second PR with them.
• Does this PR require documentation updates?
• I've updated documentation as required by this PR.
• Optional. My organization is added to USERS.md.
• I have signed off all my commits as required by DCO
• I have written unit and/or e2e tests for my change. PRs without these are unlikely to be merged.
• My build is green (troubleshooting builds).

[jannfis]

Thanks a lot for this effort, @sathieu.

We have discussed this in yesterday's contributors meeting and came to the conclusion that we may need some more design thoughts around integrating SSA into Argo CD. Many people are waiting for Server Side Apply feature for various use-cases, and therefore we should look at all the known requirements before we pull it into Argo CD. Worst case at a quick shot would be that we may end up in a situation having to introduce breaking changes for going forward.

Would you be willing to collaborate with us in this design, and then adapt the PRs to reflect the design decisions?

[sathieu]

@jannfis I would happily collaborate for the design, and I'll try to find some time to update the PR 🚀.

[hikhvar]

Any updates on the design? Can one participate or give feedback on the design somewhere?

[leoluz]

Any updates on the design? Can one participate or give feedback on the design somewhere?

@hikhvar
I'm planning to work writing the design proposal soon. Once that is done, I'm going to share the document here and in the #argo-contributors channel (CNCF slack) so people in the community can follow up/comment. You are more than welcome to participate and provide feedback if you want.

[leoluz]

@hikhvar The design proposal is available here

@sathieu This PR and the gitops-engine one are already implementing good part of the proposal. Do you want/have time to continue to work on this feature?

[sathieu]

@leoluz Thanks for the info. I won't have the time to work on this soon. The priority is now lower (we have workarounds).

[bradj]

Hey, @sathieu !

We're running into issues that are solved by serverside-apply. Wondering what your workarounds are?

[sathieu]

@bradj My workaround for prometheus CRD being too big when applied with argocd is here: https://gitlab.com/kubitus-project/kubitus-installer/-/commit/9edaf429bb7181d2b79a81fe14ce154fbdcdc93c.

[asafhm]

Would really love to see this PR gets merged, regardless of the workaround :)

[sathieu]

@asafhm Actually, argoproj/gitops-engine#363 was merged and is in gitops-engine 0.7 which is in argocd 2.4.2. So the annotation probably works already.

[Jacobious52]

@sathieu I gave this a try using the ServerSideApply=true annotation with 2.4.3 and sync fails with

PatchOptions.meta.k8s.io "" is invalid: fieldManager: Required value: is required for apply patch

[leoluz]

Closing this PR as SSA is being implemented as part of #9711