Template failureDomain default value

[evanfreed]

What steps did you take and what happened: I've been referencing the cluster-template.yaml and mixing in some of our own configuration with Kustomize. One issue I've ran into is error retrieving bootstrap data: linked Machine's bootstrap.dataSecretName is nil error message. My understanding is this error can be caused happens because a zone doesn't exist or the instance type might not be available, etc.

My issue was resolved by removing the template's MachineDeployment.spec.template.spec.failureDomain default parameter failureDomain: "${GCP_REGION}-a". I suspect this is due to better defaults or safeguards from https://github.com/kubernetes-sigs/cluster-api-provider-gcp/pull/584 being merged. It seems to me like assuming a zone a exists and has the provided types could be a poor default?

I'm happy to submit a PR if this seems reasonable.

/kind bug

Environment:

• Cluster-api version: 1.24.1
• Minikube/KIND version: 0.14.0