Lazily initialize signal handling for hyperkube apiserver and kubelet

[S-Chan]

What type of PR is this?

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/kind api-change
/kind bug
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/kind failing-test
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/kind bug

What this PR does / why we need it:
https://github.com/kubernetes/kubernetes/pull/63859/files#diff-dfaeb837c577bcd60dd9105c43427a35R52 initializes signal handling for all hyperkube commands. The function returns a stopCh that can be used by subcommands (e.g. apiserver, kubelet). However, not all subcommands make use of the stopCh. These subcommands (kube proxy, controller manager, etc) then require sending SIGTERM/SIGINT twice before exiting. Instead, we can initialize signal handling when the subcommand is actually run.

Which issue(s) this PR fixes:

Fixes #72029

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

Signal handling is initialized within hyperkube commands that require it (apiserver, kubelet)

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[k8s-ci-robot]

Hi @S-Chan. 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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[S-Chan]

Signed the CLA

[S-Chan]

/assign @mikedanese

[mattjmcnaughton]

/lgtm
/ok-to-test

Just for discussion - thoughts on if there would be a good way to unit test this? I feel like a full e2e test is overkill, but it would be interesting to think about how much lift it would be to write a unit test.

But also, I'm not sure how much that often happens for Kubernetes cmd.

[S-Chan]

Thanks @mattjmcnaughton for the review!

I feel like it's hard to avoid writing an integration test (maybe overkill) or testing implementation details for this fix. Definitely open to suggestions though.

[mattjmcnaughton]

On Thu, Apr 18, 2019 at 12:18:24PM -0700, Stephen Chan wrote: Thanks @mattjmcnaughton for the review! I feel like it's hard to avoid writing an integration test (maybe overkill) or testing implementation details for this fix. Definitely open to suggestions though. -- You are receiving this because you were mentioned. Reply to this email directly or view it on GitHub: #76659 (comment)

Yeah, tbh I'm not positive what is the best practice here - I defer to other members of the community :)

[roycaihw]

/lgtm

I'm not sure about test convention for cmd

[mikedanese]

Just call kubeapiserver.NewAPIServerCommand(server.SetupSignalHandler) here and don't modify the other files? You'll get your laziness without mucking with the signatures of the other app packages.

[S-Chan]

Do you mean kubeapiserver.NewAPIServerCommand(server.SetupSignalHandler())? This can't be done as all command functions are called during commandFor.

[sttts]

Why don't we move the SetupSignalHandler call into the commands themselves? Having this indirectional looks complex and it's not even used if I have not missed anything.

[S-Chan]

@sttts thanks for the suggestion, I've moved SetupSignalHandler into kubelet and apiserver.

[S-Chan]

/retest

[S-Chan]

/test pull-kubernetes-local-e2e

[mikedanese]

/approve

Needs a rebase, otherwise looks good.

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: mikedanese, S-Chan

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[S-Chan]

/test pull-kubernetes-local-e2e

[mikedanese]

/lgtm

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/retest
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[k8s-ci-robot]

@S-Chan: The following test failed, say /retest to rerun them all:

Test name	Commit	Details	Rerun command
pull-kubernetes-local-e2e	7cbe2d6	link	/test pull-kubernetes-local-e2e

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