title: GKE Ingress opening port
body: <p>i created a google cloud kubernetes Cluster with some api containers. They are exposed now using a load balancer. 
  But now i need to migrate to a ingress loadbalancer.
  So i exposed them via nodeport and set up the ingress load balancer.</p>
  
  <p>But now i have the problem, i need to add a firewall rule to open the NodePorts. Otherwise my Ingress healthcheck failes.
  Did i do something wrong? Or is it the only possibility to add the firewall rule?
  If yes, is there any possibility to just allow traffic from the ingress/healthcheck? 
  Otherwise i can contact my services through the IP of the nodes.</p>
  
  <p>Thanks</p>