Cloud SQL doesn't support replication or high-availability or a number of other features yet. For them you need to setup your own cluster or use another manage

Cloud SQL doesn't support replication or high-availability or a number of other features yet. For them you need to setup your own cluster or use another managed PostgreSQL service, such as our Aiven PostgreSQL (https://aiven.io/postgresql https://aiven.io/postgresql) which is available in all GCP regions.