Allow settting vCenter cluster per Machine Pool

[lukaspj]

Inspiration for incoming ticket.

We experienced our infrastructure team changing the name of the vCenter cluster, which means we can't provision new machines because the "resource pool" path was wrong, so we got this error:

We need a change that would allow us to override this field per-MachinePool so we are able to patch our MachineSets to create Machines again.

NB: I haven't tested this change, it's only for facilitating discussion

[openshift-ci]

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[openshift-ci]

Hi @lukaspj. Thanks for your PR.

I'm waiting for a openshift 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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[2uasimojo]

• Is it a common/frequent thing to rename the vcenter cluster?
• Assuming the OCP cluster uses a single failure domain (hive does not yet support multiple), is it possible for worker machines to be deployed across different vcenter clusters for the same OCP cluster?

Assuming the answer to both is "no", I think it makes sense in this case to update the Cluster in the ClusterDeployment configuration to match what was done to the vCenter. (This requires working around our webhook, which is not something we want you to do without your support agent's guidance.)

[lukaspj]

It’s an exceptional change that is not expected to happen again but evidently, we can’t be sure.

we generally only have one vCenter cluster per vSphere server, the failure domains are handled transparently by our compute team at a vm level

Edit: so yes, no to both questions