feat: add EMULATED_VERSION env var and --emulated-version flag params to k8s binaries flags in hack/local-up-cluster.sh

[aaron-prindle]

What type of PR is this?

/kind feature

What this PR does / why we need it:

As part of kubernetes/enhancements#4330, we want to add the --emulated-version flag as an option (not set by default) through our test and dev infrastructure to make it easier for users and test automation to use the flag.

This PR adds a new environment variable EMULATED_VERSION in hack/local-cluster-up.sh and adds the --emulated-version flag to the kubernetes binaries that support it currently:

• kube-apiserver
• kube-controller-manager
• kube-scheduler

From looking at similar PRs that update hack/local-up-cluster.sh similarly I believe no other files need to be touched other than the local-up-cluster.sh script directly:

• https://github.com/kubernetes/kubernetes/pull/125738/files
• https://github.com/kubernetes/kubernetes/pull/125647/files

Which issue(s) this PR fixes:

Fixes #126788

Special notes for your reviewer:

Manually tested via running hack/local-up-cluster.sh w/ and w/o EMULATED_VERSION env var set

Does this PR introduce a user-facing change?

NONE

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

[k8s-ci-robot]

Hi @aaron-prindle. 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.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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[Jefftree]

/ok-to-test

[Jefftree]

nit: Can we use --emulated-version=kube=${EMULATED_VERSION} to be aligned with #125742? It is defaulted to kube but consistency would be nice.

[aaron-prindle]

Ah good catch thanks! I've updated the value for all three flag entries as recommended. Now they are:
--emulated-version=kube=${EMULATED_VERSION}

[aaron-prindle]

I've undone this change as there was some test failures and UX issues in my testing with the "kube=" prefix added to the flag entires. The default value for EMULATED_VERSION is "" so the value passed is kube="". Going to keep the initial syntax as adding logic to prepend a suffix or use single quotes is different than other env vars in the file and also the prepending logic might confuse users. With the initial approach users can set EMULATED_VERSION=1.31 OR EMULATED_VERSION=kube=1.31

[aaron-prindle]

I've updated the script to instead use:

EMULATED_VERSION=${EMULATED_VERSION:+kube=$EMULATED_VERSION}

This way it is consistent with #125742 and has the default values we want

[Jefftree]

perfect, thanks!

[BenTheElder]

aside: in most other scripts we make the "public API" use KUBE_ but we should probably remain self-consistent within this script/tool

[Jefftree]

/sig api-machinery
/lgtm
/assign @BenTheElder
/cc @jpbetz

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: 1cb6d75f4b43f05ca7d36598436f2caf119e06b5

[aaron-prindle]

/retest

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: 7286740c464dc2625a64efa5c43852738f96cef6

[BenTheElder]

cc @liggitt

I'd prefer to get dims's input for local-up-cluster as kinda the main steward at this point, but this looks straight forward enough, I don't think we're trying to enable skew here with older releases that lack these flags.

[BenTheElder]

er cc @dims for FYI later at least

[BenTheElder]

/lgtm
/approve

[BenTheElder]

/retest

the e2e-gce failure was #126800

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: aaron-prindle, BenTheElder

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Needs approval from an approver in each of these files:

• hack/OWNERS [BenTheElder]

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[k8s-ci-robot]

@aaron-prindle: The following test 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-kubernetes-local-e2e	780cfa5	link	false	/test pull-kubernetes-local-e2e

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.

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. I understand the commands that are listed here.

[Jefftree]

/lgtm

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: 39057e4fb2f234c8c91df68c76e136bf1c1d88d4

[aaron-prindle]

/retest

[Jefftree]

@BenTheElder it seems like the job pull-kubernetes-local-e2e has not succeeded recently: https://prow.k8s.io/job-history/gs/kubernetes-jenkins/pr-logs/directory/pull-kubernetes-local-e2e. It's not blocking but is this something that is already tracked?

[fedebongio]

/triage accepted