title: Adding firewall rule for GKE nodes
body: <p>So I'm trying to achieve the following: 
  - Via Terraform deploy Rancher 2 on GCE
  - Create K8s Cluster
  - Add firewall rules so the nodes are able to talk back to the Racher Master Vm.</p>
  
  <p>I was able to add a firewall rule with the External IPs of the Nodes to access the rancher master, but instead of adding the IPs I should be able to use a tag. Google Kubernetes Engine create a compute Engine Instance Group</p>
  
  <pre><code> gke-c-wlvrt-default-0-5c42eb4e-grp
  </code></pre>
  
  <p>When I add in the firewall rules:</p>
  
  <pre><code>Target Tag: rancher-master
  Source Tag: gke-c-wlvrt-default-0-5c42eb4e-grp
  </code></pre>
  
  <p>nothing works.</p>
  
  <p>when I change it to: </p>
  
  <pre><code>Target Tag: rancher-master
  Source IP: 35.xx.xx.xx, 35.xx.xx.xx.xx, 35.xx.x.xxx.x
  </code></pre>
  
  <p>it works. </p>
  
  <p>So to I get the tags for the Kubernetes Nodes working on the firewall rule ? </p>