# Using an external PostgreSQL server (optional) By default, this playbook would set up a PostgreSQL database server on your machine, running in a Docker container. If that's alright, you can skip this. If you'd like to use an external PostgreSQL server that you manage, you can edit your configuration file (`inventory/matrix./vars.yml`). It should be something like this: ```yaml matrix_postgres_use_external: true matrix_postgres_connection_hostname: "your-postgres-server-hostname" matrix_postgres_connection_username: "your-postgres-server-username" matrix_postgres_connection_password: "your-postgres-server-password" matrix_postgres_db_name: "your-postgres-server-database-name" ``` The database (as specified in `matrix_postgres_db_name`) must exist and be accessible with the given credentials. It must be empty or contain a valid Matrix Synapse database. If empty, Matrix Synapse would populate it the first time it runs.