8 Ingress

Ingress is all about accessing multiple web applications through a single LoadBalancer Service.

Ingress fixes this by exposing multiple Services through a single cloud load-balancer.

It creates a LoadBalancer Service, on port 80 or 443, and uses host-based and path-based routing to send traffic to the correct backend Service.

The object spec defines rules that govern traffic routing, and the controller implements the rules.

Once you have an Ingress controller, you deploy Ingress objects with rules that govern how traffic hitting the Ingress is routed.

On the topic of routing, Ingress operates at layer 7 of the OSI model, also known as the “application layer”. This means it has awareness of HTTP headers, and can inspect them and forward traffic based on hostnames and paths.

Ingress exposes multiple ClusterIP Services through a single cloud load-balancer.

The way Kubernetes knows which Ingress controller to use when you deploy an Ingress object is via Ingress classes. You create Ingress classes, and then tag Ingress objects with a particular class.