Comment 3 for bug 1732082

MAAS and openstack endpoints are validated during cloud addition via Ping.

We could add validation to add-credential trying to connect to a desired cloud. At the moment, all validation of credential on the provider side is done via trying to list available, known instances. This logic will need to change to support validating functionality.

Another option is to add this validation to a FinalizeCredential() call that all providers that support authenticated requests provide. This method is called almost (if not always) everytime a credential is constructed.