Add tutorial about running Pods with sidecar containers

[SergeyKanzhelev]

/sig node

more questions about sidecars warranted me to write this down.

It was discussed at Sidecar WG meeting: https://docs.google.com/document/d/1E1guvFJ5KBQIGcjCrQqFywU9_cBQHRtHvjuqcVbCXvU/edit#bookmark=id.u4zmu7j9vn31

This is the first step in this tutorial. It may require more work in the following areas:

1. I am out of my depth on what would be the best practices writing tools and mutating web hooks that will preserve unknown fields: Add tutorial about running Pods with sidecar containers #46825 (comment) Extended documentation or even a link to other page that may explain this would go a long way. (Document the best practices when implementing mutating webhook #47465)
2. Explain how to implement sidecar containers without the built-in feature. I am not sure how deep we want to go there to cover edge cases. Perhaps just cover the very basic scenario.
3. Fully working example of a sidecar container that handles termination properly would go a long way explaining concepts.

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[sftim]

It's great that we want to help people learn about running sidecars.

How about adding a tutorial page, eg https://k8s.io/docs/tutorials/pod-sidecar-containers/?

[SergeyKanzhelev]

It's great that we want to help people learn about running sidecars.

How about adding a tutorial page, eg https://k8s.io/docs/tutorials/pod-sidecar-containers/?

Updated.

[SergeyKanzhelev]

Any advice what does this may mean:

Error: error building site: assemble: "/opt/build/repo/content/en/docs/tutorials/configuration/pod-sidecar-containers.md:1:1": got positional parameter 'or'. Cannot mix named and positional parameters

[sftim]

Any advice what does this may mean:

Error: error building site: assemble: "/opt/build/repo/content/en/docs/tutorials/configuration/pod-sidecar-containers.md:1:1": got positional parameter 'or'. Cannot mix named and positional parameters

See inline feedback (the feature-state suggestion)

[sftim]

Questions in my mind:

• After following all the steps in the tutorial, how many Pods are still running (did we explain how to clean up?)
• After following all the steps in the tutorial, how many Pods that have a sidecar container have started and become healthy?
• After following all the steps in the tutorial, how many other Pods started (eg to help make a point about failure handling)?

If we're not helping the reader to run any Pods that have sidecars, the tutorial needs expanding until that changes.

[sftim]

/retitle Add tutorial about running Pods with sidecar containers

Feedback was stale

[sftim]

My key feedback is (still) the “questions in my mind” from #46825 (review)

[T-Lakshmi]

/label tide/merge-method-squash

@SergeyKanzhelev,
can you please squash the commits.

[sftim]

/remove-label tide/merge-method-squash

[sftim]

Some more feedback. Please address the existing feedback as well.

[SergeyKanzhelev]

@sftim I think I addressed most of comments. I really want this first step out. See https://kubernetes.slack.com/archives/C0EG7JC6T/p1723141448471749

I added a few follow up steps on top that can be done. @afro-coder I think it will be easiest if we can merge this PR and if you want to contribute, can do as a follow up.

[matthyx]

great write, 100% correct regarding technicalities, thanks Sergey!
/lgtm

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: 86cedfc8871cdd6350c9c87996c2a12dba9b34f1

[tengqm]

/approve
Let's kick this in and iterate over it.

[k8s-ci-robot]

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