I followed the load balancer tutorial: https://cloud.google.com/container-engine/docs/tutorials/http-balancer which is working fine when I use the Nginx image, when I try and use my own application image though the backend switches to unhealthy.

My application redirects on / (returns a 302) but I added a livenessProbe in the pod definition:

    livenessProbe:
      httpGet:
        path: /ping
        port: 4001
        httpHeaders:
          - name: X-health-check
            value: kubernetes-healthcheck
          - name: X-Forwarded-Proto
            value: https
          - name: Host
            value: foo.bar.com

My ingress looks like:

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: foo
spec:
  backend:
    serviceName: foo
    servicePort: 80
  rules:
  - host: foo.bar.com

Service configuration is:

kind: Service
apiVersion: v1
metadata:
  name: foo
spec:
  type: NodePort
  selector:
    app: foo
  ports:
    - port: 80 
      targetPort: 4001

Backends health in ingress describe ing looks like:

backends:       {"k8s-be-32180--5117658971cfc555":"UNHEALTHY"}

and the rules on the ingress look like:

Rules:
  Host  Path    Backends
  ----  ----    --------
  * *   foo:80 (10.0.0.7:4001,10.0.1.6:4001)

Any pointers greatly received, I've been trying to work this out for hours with no luck.

Update

I have added the readinessProbe to my deployment but something still appears to hit / and the ingress is still unhealthy. My probe looks like:

    readinessProbe:
      httpGet:
        path: /ping
        port: 4001
        httpHeaders:
          - name: X-health-check
            value: kubernetes-healthcheck
          - name: X-Forwarded-Proto
            value: https
          - name: Host
            value: foo.com

I changed my service to:

kind: Service
apiVersion: v1
metadata:
  name: foo
spec:
  type: NodePort
  selector:
    app: foo
  ports:
    - port: 4001
      targetPort: 4001

Update2

After I removed the custom headers from the readinessProbe it started working! Many thanks.