Yep! GKE just runs atop GCE. No work required on your side. That reminds me though: you have to be communicating over the internal IP addresses, not the extern

Yep! GKE just runs atop GCE. No work required on your side. That reminds me though: you have to be communicating over the internal IP addresses, not the external ones (I hope the Services stuff does the right thing automatically). Firewall rules and such are different for internal versus external IPs (people often want a simple "deny all external traffic"), so that's sadly still a performance cliff.