Ingress Controllers and Ingress Resources

The Ingress API has been frozen since Kubernetes 1.19. No new features. No further development. The Kubernetes project now recommends Gateway API for new installations, and the previous article in this series covered Gateway API in detail. Yet every CKA exam includes Ingress tasks, and the large majority of production clusters still route external HTTP traffic through Ingress resources. Knowing how to create, modify, and debug Ingress is not optional.

The split that confuses most people: an Ingress resource is a declarative routing table, nothing more. It has no effect until an Ingress controller reads it and configures the actual proxy. That separation between config object and runtime is the source of most Ingress problems. You apply an Ingress, traffic doesn't route, and kubectl reports no error because from Kubernetes' perspective, everything is fine. The controller just hasn't processed it yet, or the routing config doesn't match what the controller expects.