Use Controller as default/404 backend

[bedis]

This week I had experienced a bit with an old style "service controller" (developed when ingress was not a thing in k8s). This controller exposes a local webserver on port 8081 to return 404s and that HAProxy uses as a default backend. There is one URL which does not return 404, it is "/healthz" which is useful to make Kubernetes test that both HAProxy and the controller are up and running through the liveness/readiness health checks: just run a query on port 80 for localhost.localdomain/healthz.

I think we should use the same trick so we don't have any dependencies any more on a default backend running as a third party pod / deployment / service. Maybe we can make both available for people who still want custom 404s

[oktalz]

we can have both, but this (not depending on k8s service for default backend) is a good idea.