No obvious failure if `identityRef` is omitted from `OpenStackMachineTemplate`

[stephenfin]

/kind bug

What steps did you take and what happened:

Create an OpenStackMachineTemplate that omits the spec.template.spec.identityRef field. The machine fails to be created and we see the following error from the controller:

E1127 16:20:23.342436       1 controller.go:324] "Reconciler error" err="auth option failed for cloud : Missing input for argument [auth_url]" controller="openstackmachine" controllerGroup="infrastructure.cluster.x-k8s.io" controllerKind="OpenStackMachine" OpenStackMachine="***/***" namespace="***" name="***" reconcileID=***

What did you expect to happen:

Ideally we could attempt to retrieve credentials from the cluster. In any case, if no identity ref is provided we should provide a clear failure rather than silently ignoring the issue and failing later.

Anything else you would like to add:

None.

Environment:

• Cluster API Provider OpenStack version (Or git rev-parse HEAD if manually built): v0.7.0
• Cluster-API version:
• OpenStack version: Wallaby
• Minikube/KIND version: N/A
• Kubernetes version (use kubectl version): v1.28.2
• OS (e.g. from /etc/os-release): N/A

[stephenfin]

/cc @mdbooth

[jichenjc]

Ideally we could attempt to retrieve credentials from the cluster. In any case, if no identity ref is provided we should provide a clear failure rather than silently ignoring the issue and failing later.

+1 , or should we do in webhook?

[stephenfin]

From a quick read through, we have the cluster object available earlier in the code path so it should be easy to fix this. I can take a look into this.

/assign @stephenfin