Add sentinel bootstrap file check modes in CRD

[BarthV]

https://github.com/kubernetes-sigs/cluster-api-provider-kubevirt/issues/233

[coveralls]

Pull Request Test Coverage Report for Build 4816820717

• 13 of 24 (54.17%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.02%) to 52.519%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
api/v1alpha1/zz_generated.deepcopy.go	0	11	0.0%
<!--	Total:	13	24	54.17%	-->

Totals
Change from base Build 4542574610:	0.02%
Covered Lines:	959
Relevant Lines:	1826

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💛 - Coveralls

[agradouski]

should we include this in kubevirtmachine spec explicitly as part of this PR, given that default value is "ssh" anyway:

virtualMachineBootstrapCheck:
         checkStrategy: ssh

I know we made it backward compatible, and this is not required in the template, asking more wrt potentially confusing existing users.

one advantage of making it explicit is perhaps giving users heads up about changes (current and future) in that part of logic.

@davidvossel @pjaton wdyt?

[agradouski]

/lgtm

[pjaton]

should we include this in kubevirtmachine spec explicitly as part of this PR, given that default value is "ssh" anyway:

virtualMachineBootstrapCheck:
         checkStrategy: ssh

I know we made it backward compatible, and this is not required in the template, asking more wrt potentially confusing existing users.

one advantage of making it explicit is perhaps giving users heads up about changes (current and future) in that part of logic.

@davidvossel @pjaton wdyt?

In this case, I feel that the expected behavior by most users is really about "please use the default mechanism"; so, using unset to mean default feels more intuitive to me than making this required. I do see your point about future change, though, I simply see that there would be more impact if this is made required.

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: agradouski, BarthV, pjaton

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