I believe parent was commenting about ability to run a CloudSQL instance with an internal IP in the same&#x2F;different subnet as rest of the Compute Engine instance.  I&#x27;m drawing that conclusion because I&#x27;ve had the <i>exact</i> same use case and I ended up using SSL certs used by Cloud SQL instances to secure communication between my apps running on compute engine and CloudSQL.<p>With RDS one can create a postgres&#x2F;mysql instance that shares the same internal subnet thus negating need to open it up to external IPs, something I had to do after much deliberation because whitelist individual instance IP is just too much pain.<p>[edit: I looked at the link, and created a test instance to make sure I wasn&#x27;t missing on a config setting, still unable to use private network to communicate with Cloud SQL AFAIK]