Amend keps/sig-apps/sidecarcontainers.md to reflect kubernetes/kubernetes#52345

[ghost]

This issue proposes an amendment to the existing sidecarcontainers KEP:
https://github.com/kubernetes/enhancements/blob/master/keps/sig-apps/sidecarcontainers.md

The issue kubernetes/kubernetes#52345 and associated PR were closed in favor of the sidecarcontainers KEP.

Reading through the sidecarcontainers KEP, it is unclear that the concerns outlined in kubernetes/kubernetes#52345 will be addressed, specifically that configuration will allow the initContainer(or pod or sidecar-initContainer) to be restarted when a specific container errors.

I propose that kubernetes/kubernetes#52345 be listed in either the goals or non-goals section of the sidecarcontainers KEP. In the case it is included in goals, further elaboration could be provided in other appropriate sections. In the case it is included in non-goals, a new KEP can be proposed.

[ghost]

/sig apps
/sig node

[ghost]

An idea to address kubernetes/kubernetes#52345 would be to allow a new type of initContainer associated with a single container (CIC). This approach would solve the life-cycle problem, ensuring that only the CIC is run prior to restarting the container. The current pod initContainer(s) continues to run only when the pod restarts and the new CIC runs prior to a specific container.

[ghost]

#753

[Joseph-Irving]

Hi, this was discussed a few times during the creation of the sidecars KEP and it never seemed to fit in with the problems we were trying to solve nor the solution we were suggesting, it makes a lot more sense, to me at least, to solve this in a separate KEP.

[ghost]

I agree that a separate KEP makes sense. I will close this issue and open a new one to propose the new KEP.

[mtritschler]

@majgis could you post a link to that new KEP or a PR? Thanks

[ghost]

@mtritschler Thank you for the reminder. I'll make sure that is created this weekend and post the link here.

[ghost]

#871