[feature request] In-place update specified container without marking pod not ready

[ABNER-1]

What would you like to be added:

Enable users to control whether a pod should be marked as unready during in-place updating some containers.

Why is this needed:

In Kruise, we have introduced the InPlaceUpdateReady readiness gate, which is set to not ready before initiating an in-place update for a container.

When utilizing Kruise to perform in-place updates on less critical containers, there is a limitation: even if you configure the CloneSet lifecycle, you cannot prevent the pod from being marked as not ready during the update process.

[jairuigou]

Hi, Is there any progress on this? I think we might need to determine in CalculateSpec whether to skip marking the Pod as NotReady based on the container names involved in this in-place update. These container names can be configured under lifecycle, for example:

lifecycle:
  inPlaceUpdate:
    markPodNotReady: true
    finalizersHandler:
    - example.io/unready-blocker
    ignoreContainersForReady:
    - container1
    - container2

[ABNER-1]

Hello，@jairuigou.
We have discussed it in the Bi-weekly Community Meeting and have reached some conclusions:

• We need to draft a proposal to thoroughly discuss several implementation methods: adding an identifier in the environment, including an additional field in the update strategy, and specifying within the lifecycle.
• It is necessary to review the two readiness gates to see if they can be merged from a scenario perspective to avoid increasing complexity.