Phenomenon

After creating an address, it is found that no address is assigned:

kubectl describe expressions kubia Default HTTP backend not found when viewing expressions

reason

The ingresses component cannot exist alone. It depends on the ingresses controller component. In the process of creating the ingresses controller, you need to configure a default backend.

See [k8s] ingress service and ingress controller

Default backend function:
the principle of ingresses is similar to nginx. For URL forwarding, you need to customize rules. A portal without rules sends all traffic to a default backend. The default backend is usually a configuration option for the progress controller.

If neither the host nor the path in the ingress object matches the HTTP request, the traffic will be routed to the default backend.