update SidecarContainers to stable in v1.33

[pacoxu]

ref to kubernetes/enhancements#753

• Promote SidecarContainers feature to GA kubernetes#129731 was merged to promote the feature gate.

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[pacoxu]

/cc @SergeyKanzhelev

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[pacoxu]

/cc @gjkim42

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[sftim]

Thanks, but we also need to reword https://kubernetes.io/docs/concepts/workloads/pods/sidecar-containers/#pod-sidecar-containers because the feature gate will no longer control behavior.

You should change this page or ask another contributor to help with the revision.

---

@pacoxu if you can rally someone from SIG Node who is keen to help, https://kubernetes.io/docs/tutorials/configuration/pod-sidecar-containers/ is not yet quite at the quality level we'd like for beta. That fact doesn't block graduation but if we can improve that tutorial and polish it more, even better.

[kundan2707]

Preview

[pacoxu]

I find that #46525 did some rephrase based on @matthyx 's #43471 beta update doc PR. https://kubernetes.io/docs/concepts/workloads/pods/pod-lifecycle/#termination-with-sidecars(and some context above this )

@matthyx @SergeyKanzhelev for GA, do we want to publish a blog?

@pacoxu if you can rally someone from SIG Node who is keen to help, https://kubernetes.io/docs/tutorials/configuration/pod-sidecar-containers/ is not yet quite at the quality level we'd like for beta. That fact doesn't block graduation but if we can improve that tutorial and polish it more, even better.

I could help on improve that part based on merged KEP and merged PRs.
/hold
@sftim Do you have a clear optimization direction, such as wanting the description to be clearer, adding more technical details, providing additional examples, or including use cases? I may proposal some later for review.

[matthyx]

@matthyx @SergeyKanzhelev for GA, do we want to publish a blog?

yes and a celebration in London !

[sftim]

To improve https://kubernetes.io/docs/tutorials/configuration/pod-sidecar-containers/:

• make it a tutorial about using sidecar containers, not a tutorial about switching to the initContainers-that-stay-running paradigm

• actually demonstrate a sidecar; for example, have a main app container that displays a trending fruit (we use fruit in examples such as https://kubernetes.io/docs/tasks/job/parallel-processing-expansion/) on a webpage. Accompany that with a sidecar that picks a random fruit to be the trending one.

• actually demonstrate a sidecar that starts before a later init container and also before an app container
  (maybe the init container writes a page that reads "We don't have any trending fruit yet"

• maybe also demonstrate a sidecar container that reads from a (mounted) log file and writes entries to its stdout

[sftim]

On the tutorial, I also recommend illustrating general good practice; for example, have a Pod template with a selector on kubernetes.io/os rather than assume that the cluster is all Linux.