Ingress gives 502 error

Question

If I run through the http load balancer example it works fine in my google container engine project. When I run "kubectl describe ing" the backend is "HEALTHY". If I then change the svc out to one that points to my app as shown here:

apiVersion: v1
kind: Service
metadata:
  name: app
  labels:
    name: app
spec:
  ports:
  - port: 8000
    name: http
    targetPort: 8000
  selector:
    name: app
  type: NodePort

The app I'm running is django behind gunicorn and works just find if I make that a load balancer instead of a NodePort.

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: main-ingress
spec:
  backend:
    serviceName: app
    servicePort: 8000

Now when I run "kubectl describe ing" the backend is listed as "UNHEALTHY" and all requests to the ingress IP give a 502.

1. Is the 502 a symptom of the bad health check?
2. What do I have to do to make the health check pass? I'm pretty sure the container running my app is actually healthy. I never set up a health check so I'm assuming I have to configure something that is not configured, but my googling hasn't gotten me anywhere.

Answer 1

After a lot of digging I found the answer: According to the requirements here: https://github.com/kubernetes/kubernetes/tree/master/cluster/addons/cluster-loadbalancing/glbc#prerequisites the application must return a 200 status code at '/'. Because my application was returning a 302 (redirect to login), the health check was failing. When the health check fails, the ingress resource returns 502.