feat(nodepool): support timezone for disruption budgets

[flavono123]

Fixes #1446, partially

Description

add the field disruption.budgets[].timeZone for NodePoolSpec.
if not set, use UTC as default.
validate if not schedule is set, timeZone also cannot be.

referenced one in CronJobSpec and already tried PR #1447

How was this change tested?

make verify && go test ./pkg/apis/v1/

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

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[flavono123]

are we have to emit a new event for a wrong timezone?:

If the time zone name becomes invalid during the lifetime of a CronJob or due to a change in host configuration, the controller will stop creating new new Jobs and will create a system event with the reason UnknownTimeZone

https://kubernetes.io/docs/reference/kubernetes-api/workload-resources/cron-job-v1/#CronJobSpec

[coveralls]

Pull Request Test Coverage Report for Build 15434332727

Details

• 12 of 16 (75.0%) changed or added relevant lines in 2 files are covered.
• 15 unchanged lines in 3 files lost coverage.
• Overall coverage decreased (-0.09%) to 81.958%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pkg/apis/v1/zz_generated.deepcopy.go	1	5	20.0%

Files with Coverage Reduction	New Missed Lines	%
pkg/controllers/disruption/consolidation.go	4	85.55%
pkg/controllers/provisioning/scheduling/topologydomaingroup.go	4	86.21%
pkg/controllers/provisioning/scheduling/preferences.go	7	88.76%

Totals
Change from base Build 15430250801:	-0.09%
Covered Lines:	10262
Relevant Lines:	12521

---

💛 - Coveralls

[flavono123]

@njtran could you mind to review this?

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[jonathan-innis]

@flavono123 Would you mind coming to one of our Working Group meetings and we can discuss this one more? I think there are some tricky things with handling timezones that we have generally avoided but open to talk more about your use-case.

[flavono123]

@jonathan-innis thanks for inviting me. i'd like to, but two things are hurdles for me:

• I'm afraid to understand the conversation in real time, honestly, I'm not good at English, both speaking and listening, so it would be good if there is support for translation.
• Time is dawning for me, another time zone problem.

so let me explain my use-case in "text", in advance:

    - duration: 21h
      nodes: "0"
      schedule: 0 21 * * sun-thu

I use budgets like the one above to allow disruptions from 3am to 6am, Monday to Friday in KST(actually, leveraging does not allow from 6am to 3am tomorrow to avoid working time). I think it is more confusing when the duration is over the date and with weekdays for my case.

In short, this is just a literal time zone issue to make it easier to figure out the time span of budgets.

[engedaam]

/assign @elmiko

[elmiko]

putting this in my queue for the week, my intention is to review the various places where a time value is used and enumerate them in a doc. then we can review the doc to see if we should update all the time uses to include a user-specified timezone.

[elmiko]

i poked around the karpenter code this week and i think we can confirm the the nodepool.spec.disruption.budgets.schedule is the only place where we currently accept a date-like format, or cron format.

if we wanted to support timezones for disruption budgets, i think we would want to add a nodepool.spec.disruption.budgets.timeZone field, similar to how core kubernetes allows a timezone field in cronjob specs.

[jonathan-innis]

@elmiko It looks like the PR now supports your suggestion about using a separate timeZone field in the budgets section -- is this PR ready for another round of review?

[elmiko]

this is looking good to me

[nandorKollar]

nit: reutn -> return :)