Whitelisting Google App Engine in google VM instance

[sujesh thekkepatt]

I have a nodejs app running on google app engine flexible instance.  Also, have another service running on VM instance. Both are in same projects. I want the VM instance service exposed only to the APP engine service. How do i whitelist/ create the necessary firewall rule ? I have tried whitelisting for specific service account but not works. ANy help would be appreciated

[George (Cloud Platform Support)]

Hello Sujesh, 

If you want your VM instances to use internal IP addresses instead of external IP addresses, you can use Private services access in a Virtual Private Cloud (VPC) network. You can read more about VPCs on the "Virtual Private Cloud (VPC) network overview" page.