Currently, the ingress clusteroperator does not validate that an ingresscontroller's `.spec.domain` field is configured properly, which can result in the router pods entering a CrashLoopBackOff state immediately upon creation.  

For example, prepending an otherwise valid domain with `*.<domain>` will be accepted by the apiserver, but result in pods that will fail immediately with the following error: 

error: invalid canonical hostname: router-<IC name>.*.<domain>

Rather than allow the ingresscontroller to be created and it's resulting pods fail, the ingress clusteroperator should reject ICs with invalid domains outright.
    

4.18.7
    

Always
    

    1. Create a custom ingresscontroller with an invalid .spec.domain. For example, set .spec.domain to '*.myexampledomain.com' 
    2. The apiserver and ingress CO will accept the incorrectly configured IC, and create router pods
    3. The router pods will immediately fail with an `invalid canonical hostname` message
    

Ingresscontroller can be created with an invalid domain
    

An incorrectly configured ingresscontroller is rejected by the apiserver and/or ingress clusteroperator