When pod listing, filter out unschedulable and scheduler unprocessed pods not in the list of allowed schedulers

[damikag]

When pod listing, filter out unschedulable and scheduler unprocessed pods not in the list of allowed schedulers.

What type of PR is this?

/kind feature

What this PR does / why we need it:

This PR introduces new command line flag where a list of schedulers can be specified. If specified, cluster autoscaler will filter out pods not belong to those schedulers at the very beginning of the CA loop.

This feature is useful for customs CA configurations where CA does not intends to help pods targeting some custom schedulers. Specially in large clusters when there are thousands of unschedulbale pods which are not intended for CA, it adds unnecessary extra overheads and could affect CA decision making. This flag can be used as a mitigation for such cases.

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?

The flag should be set to empty for general release. This flag should only be used for specific clusters which have any such needs or as a mitigation tool if applicable.

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

[k8s-ci-robot]

@damikag: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-autoscaling-e2e-vpa-recommender	6b8471c	link	true	/test pull-autoscaling-e2e-vpa-recommender
pull-autoscaling-e2e-vpa-admission-controller	6b8471c	link	true	/test pull-autoscaling-e2e-vpa-admission-controller
pull-autoscaling-e2e-vpa-updater	6b8471c	link	true	/test pull-autoscaling-e2e-vpa-updater
pull-autoscaling-e2e-vpa-actuation	6b8471c	link	true	/test pull-autoscaling-e2e-vpa-actuation
pull-autoscaling-e2e-vpa-full	6b8471c	link	true	/test pull-autoscaling-e2e-vpa-full
pull-cluster-autoscaler-e2e-azure-master	6b8471c	link	false	/test pull-cluster-autoscaler-e2e-azure-master

Full PR test history. Your PR dashboard. Please help us cut down on flakes by linking to an open issue when you hit one in your PR.

Details

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[k8s-triage-robot]

This PR may require API review.

If so, when the changes are ready, complete the pre-review checklist and request an API review.

Status of requested reviews is tracked in the API Review project.

[k8s-triage-robot]

This PR may require API review.

If so, when the changes are ready, complete the pre-review checklist and request an API review.

Status of requested reviews is tracked in the API Review project.

[x13n]

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: damikag, x13n

The full list of commands accepted by this bot can be found here.

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Details

Needs approval from an approver in each of these files:

• cluster-autoscaler/OWNERS [x13n]

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[jackfrancis]

/cherry-pick cluster-autoscaler-release-1.35

[k8s-infra-cherrypick-robot]

@jackfrancis: new pull request created: #9165

Details

In response to this:

/cherry-pick cluster-autoscaler-release-1.35

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-sigs/prow repository.