[Umbrella] Skip Score plugins when coupled PreScore plugin returns Skip status

[sanposhiho]

What would you like to be added?

It's much similar to #114399.
In #114827, we support Skip in PreScore/Score as well. (Thanks @kidddddddddddddddddddddd)
So, the plugin can return Skip in PreScore when it doesn't do anything in Score in that scheduling cycle.

For example, if the pod doesn't have any preferred inter-pod affinity, the inter-pod affinity plugin PreScore can return Skip, and the scheduler won't run the inter-pod affinity plugin Score.

Let's change our in-tree Score plugins to return Skip.

Here, I just listed all score plugins, not all of them may not need to return Skip in PreScore though. Assignee, please make sure your PreScore/Score plugin really needs to return Skip or not.

Please feel free to assign what you'd like to work on. And please comment in this issue before starting to work on so that we can avoid many people from working on the same thing!

• ImageLocality @tangwz no need.
• InterPodAffinity @utam0k Return Skip in InterPodAffinity#PreScore under specific conditions #117794
• NodeAffinity @sanposhiho feature(NodeAffinity): return Skip in PreScore when nothing to do in Score #117024
• Fit @tangwz no need.
• BalancedAllocation @tangwz no need.
• PodTopologySpread @utam0k Return Skip in PodTopologySpread#PreScore under specific conditions #118608
• SelectorSpread; no need. It'll soon be removed. remove SelectorSpread plugin #108444
• TaintToleration @tangwz no need. feat(tainttoleration): return Skip status in PreScore #118324
• VolumeBinding @kidddddddddddddddddddddd feature(volumebinding): Implement PreScore for VolumeBinding plugin to skip score #115768

Why is this needed?

The scheduler can know which plugins it really needs/doesn't need to run to get the scheduling result.
It'd contribute to the scheduling performance.

/sig scheduling
/assign

[k8s-ci-robot]

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[sanposhiho]

I'm thinking work on InterPodAffinity and NodeAffinity because I worked on the Skip implementation in PreFilter/Filter for them.

[sivchari]

@sanposhiho
Please assign me to ImageLocality, PodTopologySpread and TaintToleration 👍
If there is no one else to work on it, I'll do it.

[AxeZhan]

I'd like to work on VolumeBinding since I worked on it before.

[tangwz]

@sanposhiho I'd like to work on Fit, BalancedAllocation.

[tangwz]

@sanposhiho @alculquicondor For Fit and BalancedAllocation, I think If the plugin's args Resources not set, we can return a error in PreScore Plugin, but Skip does not need to implement.

[alculquicondor]

Today, if args.resources is empty, scores return zero, but it doesn't produce an error. This doesn't make sense, but someone could have made a mistake. If we start returning an error, they would have to change their configuration to keep the scheduler running. I don't think we should be doing that.
In theory, if all nodes return the same score, we could return Skip, but since this is not a valid use case, I think we are adding complexity for no value. So I think we should leave it as is. At most, I would just produce a log line saying that not setting resources would not produce a meaningful score.

[sanposhiho]

@sivchari Do you still plan to work on it? or want anyone to take over them?

[sivchari]

@sanposhiho
Sorry, I'll work on it.

[alculquicondor]

@sivchari was there any progress on the PodTopologySpread?

[sivchari]

@alculquicondor
There is no progress on the PodTopologySpread 🙇

[utam0k]

I talked to @sanposhiho elsewhere and was given a chance to work on PodAffnitiy.

[utam0k]

@sanposhiho May I ask you to assign me to this issue to avoid missing 🙏 ?

[sanposhiho]

/assign @utam0k

[utam0k]

@sanposhiho Is there anything else I can help with that you would like to do? Of course, I can take another issue.

[sanposhiho]

I think you can help some @sivchari has, they all have been pending for quite long time.
How about PodTopologySpread?

[utam0k]

@sanposhiho I can take it. Please assign me 🙏

[sanposhiho]

Can anyone be a volunteer for TaintToleration or ImageLocality?

[tangwz]

@sanposhiho please assign me

[sanposhiho]

/assign @tangwz

FYI, @sivchari I reassigned them to @tangwz. You can still help with the review on them.

[sanposhiho]

The last one is merged, we can close it now finally 🎉
#117024

/close

[k8s-ci-robot]

@sanposhiho: Closing this issue.

In response to this:

The last one is merged, we can close it now finally 🎉
#117024

/close

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.