option to enable global access for internal passthrough load balancers

[hrbasic]

/kind feature

What this PR does / why we need it:
When Cluster API (CAPI) is deployed in a different region or outside of the Google Cloud Platform (GCP), reconciliation fails because CAPI cannot reach the control plane API. Enabling the global access option on the internal passthrough load balancer would resolve this issue.

Which issue(s) this PR fixes
Fixes #1468

Release note:

Option for enabling global access for internal passthrough load balancer.

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[richardcase]

/ok-to-test

[richardcase]

Thanks for this @hrbasic 🙇

The pointer isn't needed on the bool field if you don't want to distinguish between "not set" and "false".

Apart from that, looks good to me.

[richardcase]

Suggested change

	AllowGlobalAccess *bool `json:"allowGlobalAccess,omitempty"`
	AllowGlobalAccess bool `json:"allowGlobalAccess,omitempty"`

[damdo]

The use of Booleans in new Kubernetes (and CAPI) APIs is strongly discouraged.
Reference in the Kubernetes API conventions: https://github.com/kubernetes/community/blob/master/contributors/devel/sig-architecture/api-conventions.md#primitive-types

Think twice about bool fields. Many ideas start as boolean but eventually trend towards a small set of mutually exclusive options. Plan for future expansions by describing the policy options explicitly as a string type alias (e.g. TerminationMessagePolicy).

The suggested replacement is to use an Enum Type. So for example in this case you could define something like:
internalAccess, which can take two values: Regional | Global

[richardcase]

Thats a good point @damdo. And KAL will pick that up when we add it.

I don't feel overly opinionated on the use of a bool here, but an enum will be more future-proof for sure.

[hrbasic]

Thank you for your review and comments. I've updated the code to use an enum instead of a bool, as you suggested. Please let me know if there's anything else you'd like me to address.

[damdo]

Thanks for the change to Enum, I left some nits on the consts naming but mostly LGTM

[richardcase]

/approve

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[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: hrbasic, richardcase

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[damdo]

/lgtm