Kubernetes ingress path rules longest match first not working

Question

I have a deployment that has a single ingress definition that uses paths to direct requests for two services/pods on the backend

• one pod is for api
• one pod is for ui

The web address should only go to api if the URL contains /api/<anything>, otherwise everything else should go to ui.

My ingress setup looks like this

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: myapp
  namespace: "myapp"
  labels:
    app.kubernetes.io/name: myapp
spec:
  ingressClassName: nginx
  rules:
    - host: myapp.dev
      http:
        paths:
          - path: /api/
            pathType: Prefix
            backend:
              service:
                name: myapp-api
                port:
                  name: http
          - path: /
            pathType: Prefix
            backend:
              service:
                name: mayapp-ui
                port:
                  name: http

If I test with https://myapp.dev/api/endpoint, the requests are sent round robin to both backend pods (I can see the requests in the logs in the ui pod).

I was under the impression that as /api/endpoint was in the path, it should always match on the longest rule and only ever send to the api pod?

Have I misunderstood how path matching works?

Many thanks

Answer 1

Your paths are not unique.

You should add the rewrite-target under annotations:

metadata:
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: "/$1"
  namespace: default

and edit the paths names to map your cases:

 paths:
  - path: /(.*)
    pathType: Prefix
    backend:
      service:
        name: mayapp-ui
        port:
          name: http
  - path: /(api(?:/|$).*)
    pathType: Prefix
    backend:
      service:
        name: myapp-api
        port:
          name: http