nginx controller and ingress - how is nginx controller and ingress linked?

Solution 1:

The default deployment of the NGINX Ingress controller is cluster-wide, meaning a single NGINX ingress controller watches/handles Ingress resources created in any/all namespaces. I assume this is actually what you want.

If you want to have different controllers watching different namespaces, then you can deploy multiple instances and control which namespaces each watches via the -watch-namespace command-line arg.