How can I use rewrite-target on the root path with Azure Kubernetes Service?

Question

I want to have an API service that I want to reach under /api, and other requests to fall back to a frontend service.

Peculiar is that this worked locally with minikube, but now that I deployed on Azure Kubernetes Service (I used this official MS tutorial to add an ingress controller), I can not get it to work.

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: my-ingress
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /$1
spec:
  rules:
  - http:
      paths:
      - path: /api/(.*)
        pathType: Prefix
        backend:
          service:
            name: api-service
            port:
              number: 9002
      - path: /(.*)
        pathType: Prefix
        backend:
          service:
            name: frontend-service
            port:
              number: 9001

That worked just fine on minikube, but on AKS, this causes a timeout when I try to open the publicly available IP. I have tried the following things:

• Change the frontend path to (/|$)(.*)
  Together with changing the rewrite-target to /$2. kubectl will not even deploy this because the path needs to be absolute.
• Change the frontend path to /
  Now everything returns the frontend index.html, even if the request is for /style.css or favicon.ico etc. (unless it starts with /api).
• Change the frontend path to / and remove the rewrite-target
  Then the frontend works fine, but the api service doesn't "fit" as intended. The api service has a call /get-employee, which I want to call under /api/get-employee, but I can't do that unless the api service itself would already have it under /api/get-employee.

How can I add a "root" or "fallback" service while still using rewrite-target?

Answer 1

I had the same issue when trying Microsofts tutorial. Adding host under the rules section worked for me.

Example:

spec:
  ingressClassName: nginx
  rules:
  - host: {your_app}.northeurope.cloudapp.azure.com
    http:
      paths:
      - path: /test(/|$)(.*)
        pathType: Prefix
        backend:
          service:
            name: mockserver-service
            port:
              number: 1234