Ingress and routing

One entry point, many services

An ingress is a routing rule set: this hostname and path go to that service. Without it, every externally reachable service needs its own cloud load balancer, which is expensive and unwieldy.

The resource does nothing on its own — a controller running in the cluster watches ingress objects and configures a proxy. Which controller you run determines the annotations and features available to you.

Path matching rules are more precise than they look. Prefix and exact matching behave differently, and rewriting is controller-specific rather than part of the standard.