Add e2e test for HPA behavior: decreased downscale stabilization

[pbetkier]

What type of PR is this?

e2e test (what's the proper kind for this?)

What this PR does / why we need it:

Currently there are no e2e tests for HPA behavior. They are requested by #102369. More PRs will follow for other cases.

Which issue(s) this PR fixes:

Special notes for your reviewer:

Does this PR introduce a user-facing change?

NONE

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

[k8s-ci-robot]

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[k8s-ci-robot]

Hi @pbetkier. Thanks for your PR.

I'm waiting for a kubernetes member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[pbetkier]

cc @josephburnett

[pbetkier]

cc @krzysied @jbartosik

[oomichi]

What is different from the existing tests of https://github.com/kubernetes/kubernetes/blob/b917653296b6fcac2220afb3ef4f8ed50a2025a2/test/e2e/autoscaling/horizontal_pod_autoscaling.go ?

/cc @oomichi

[pbetkier]

The tests in horizontal_pod_autoscaling.go have looser expectations. They work on default settings (basic scenarios) and verify that an expected state is eventually reached. They often verify decision stability (~20min runs per test by desgin). They also verify support for all types of targets (Deployment, ReplicaSet, ReplicationController).

The behavior tests are meant to verify exactly how the state was reached, exercising various configuration options of the behavior spec. This test here is about downscale stabilization period (note the downScaleStabilization passed to HPA creation function), but 2-3 more are coming.

The test setups for horizontal_pod_autoscaling.go, horizontal_pod_autoscaling_behavior.go and custom_metrics_stackdriver_autoscaling.go should eventually converge to reduce duplication. I plan to do it after I finish all the behavior tests and know the exact needs for the new, common setup.

[pbetkier]

Rebased to contain #108104 and addressed comments from @jbartosik.

[jbartosik]

/lgtm
/approve

[jbartosik]

/ok-to-test

[jbartosik]

/remove-lgtm

let's wait for tests

[jbartosik]

/lgtm cancel

[pbetkier]

/retest

[pbetkier]

/retest

[pbetkier]

I'm going to rebase. I've seen other PRs also fail on these conformance tests before. Note that my changes don't touch code used in conformance.

[pbetkier]

/retest

[pbetkier]

@jbartosik finally the tests passed.

[jbartosik]

/lgtm
/approve

[pbetkier]

@oomichi could you have a look?

[pbetkier]

@MaciekPytel could you have a look as a sig-autoscaling approver?

[pbetkier]

@fejta could you approve as a sig-testing approver?

[MaciekPytel]

/approve

[fejta]

Can we please create an OWNERS file in https://github.com/kubernetes/kubernetes/tree/13c3f091a7d6e0dec6e329c9d511875aae337661/test/e2e/framework/autoscaling that allows the autoscaling team to approve autoscaling test framework PRs?

/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: fejta, jbartosik, MaciekPytel, pbetkier

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

The pull request process is described here

Needs approval from an approver in each of these files:

• test/e2e/autoscaling/OWNERS [MaciekPytel,fejta]
• test/e2e/framework/OWNERS [fejta]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[pbetkier]

Can we please create an OWNERS file in https://github.com/kubernetes/kubernetes/tree/13c3f091a7d6e0dec6e329c9d511875aae337661/test/e2e/framework/autoscaling that allows the autoscaling team to approve autoscaling test framework PRs?

Yes! I had this idea today as well. Will do.

[pbetkier]

/kind feature