Kubernetes Ingress Not Working - "ingress class not found" / No Address in CI

An Ingress is only acted on by a controller that owns its class. With no ingressClassName (and no default IngressClass), or a class no installed controller serves, nothing claims the Ingress - it gets no address and routes nowhere.

What this error means

kubectl get ingress shows an empty ADDRESS, and traffic to the host 404s or never connects. kubectl describe ingress shows no controller events, or the controller logs ingress class "x" is not found.

kubectl output

$ kubectl get ingress
NAME   CLASS    HOSTS         ADDRESS   PORTS   AGE
api    <none>   api.example            80      8m
# controller log: ignoring ingress api: no IngressClass / class "nginx" not found

Common causes

No ingressClassName and no default class

Modern controllers ignore Ingresses without a matching class unless one IngressClass is marked default. An Ingress with no class and no default is claimed by nobody.

Class name does not match the controller

A ingressClassName: nginx with no nginx IngressClass installed (or a different controller’s class) means no controller owns it.

How to fix it

List the available classes and the Ingress class

Terminal

kubectl get ingressclass
kubectl get ingress <name> -o jsonpath='{.spec.ingressClassName}'; echo

Set a class the controller serves

Reference an existing IngressClass (or mark one default), then confirm the Ingress gets an address.

ingress.yaml

spec:
  ingressClassName: nginx   # must match an installed IngressClass
# or mark one default:
# kubectl annotate ingressclass nginx ingressclass.kubernetes.io/is-default-class=true

How to prevent it

Always set ingressClassName explicitly to an installed class.
Mark exactly one IngressClass default if you rely on the default behavior.
Verify the Ingress receives an ADDRESS as part of a deploy check.