[HPA e2e] Reduce possible number of scale steps to minimize stabilization test flakiness

[pbeschetnov]

What type of PR is this?

/kind bug
/kind flake

What this PR does / why we need it:

This PR reduces HPA stabilization test flakines.

Which issue(s) this PR fixes:

In this test we scale up from 2 -> 4, and back 4 -> 2 using scaleUp/scaleDown stabilization windows = 3m.

Consider scale up: the resource consumer asks for CPU usage of 4 replicas, sometimes it's not that precise and it appears to consume only 3 replicas usage. So, after the stabilization windows passes, we scale up from 2 to 3. Then we have to wait another 3m to scale up to 4 replicas. The test expects to scale up in one step 2 -> 4 and spend 3m on that. In reality it is 2 -> 3 -> 4 (6m). Finally, the test timeouts because of that.

I propose to eliminate possible intermediate steps and scale always between 2 and 3 replicas. This doesn't sacrifice precision, because it's verified in other HPA tests.

Does this PR introduce a user-facing change?

NONE

[k8s-ci-robot]

Hi @pbeschetnov. 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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[k8s-ci-robot]

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[sanposhiho]

/lgtm
/ok-to-test

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: d19aaccd9abe3c760bc038e073a97cdc593d34c7

[sanposhiho]

/retest

flaky #116061

[pbeschetnov]

/retest

[pbeschetnov]

/assign @mwielgus

[mwielgus]

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: mwielgus, pbeschetnov

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• test/e2e/autoscaling/OWNERS [mwielgus]

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