How do set up a default page vs the

Default backend 404

message? I have several hostnames that resolve various subdomains but want to handle the case where a user enters the wrong domain.

You would configure it in your ingress settings

I was going to say the same thing. Also depending on your choice of ingress provider (Traefik, Istio's Envoy, etc.) I like traefik and have been using that in a purely docker world as it can do almost everything I was able to do with F5 application delivery controllers).