I expose my nginx service through traefik ingress controller. Unfortunately, it results with 503 error.

$ kubectl create deployment nginx --image=nginx
$ kubectl expose deployment nginx --port=80

My traefik ingress configuration following this documentation.

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: example
  annotations:
    kubernetes.io/ingress.class: traefik
spec:
  rules:
  - host: example.com
    http:
      paths:
      - path: /
        backend:
          serviceName: nginx
          servicePort: http