We are running several services in a Kubernetes cluster on GKE (Google Kubernetes Engine) and are having trouble configuring routing with Ingress.

Let's say that we have auth-service and user-service and would like to access them by the following urls: http://www.example.com/auth and http://www.example.com/user. All requests to these urls should be redirected to the correct services and routed internally (http://www.example.com/user/people -> http://user-service/people).

These is our configuration for the auth service:

apiVersion: apps/v1beta1
kind: Deployment
metadata:
  name: api-auth
spec:
  replicas: 1
  template:
    metadata:
      labels:
        app: api-auth
        tier: backend
        track: stable
    spec:
      containers:
        - name: api-auth
          image: "<our-image>"
          ports:
            - name: http
              containerPort: 9000
          livenessProbe:
            httpGet:
              path: /health
              port: 9000
            initialDelaySeconds: 180
            timeoutSeconds: 5
          readinessProbe:
            httpGet:
              path: /health
              port: 9000
            initialDelaySeconds: 180
            timeoutSeconds: 5
---
kind: Service
apiVersion: v1
metadata:
  name: auth-service
  labels:
    app: api-auth
spec:
  type: NodePort
  selector:
    app: api-auth
    tier: backend
  ports:
  - port: 80
    targetPort: 9000

Internally, the service is running on Tomcat on port 9000, this part is working fine.

The problem is with our Ingress configuration:

kind: Ingress
apiVersion: extensions/v1beta1
metadata:
  name: auth-ingress
  annotations:
    kubernetes.io/ingress.global-static-ip-name: <our-static-api>
    kubernetes.io/ingress.class: "gce"
  labels:
    app: api-auth
spec:
  rules:
  - http:
      paths:
      - path: /auth
        backend:
          serviceName: auth-service
          servicePort: 80
      - path: /auth/*
        backend:
          serviceName: auth-service
          servicePort: 80
      - path: /user
        backend:
          serviceName: user-service
          servicePort: 80
      - path: /user/*
        backend:
          serviceName: user-service
          servicePort: 80

Whenever I access our static api (let's call it example.com for now) in the following way: http://www.example.com/auth, I am getting 502 - Bad gateway. Running kubectl describe ingress says, that our services's health is unknown.

I am running our of ideas what might be causing this strange behavior. Could someone point me to the right direction?