# 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/host_vars/matrix.<your-domain>/vars.yml`).

It should be something like this:

```yaml
matrix_postgres_enabled: false

# Rewire Synapse to use your external Postgres server
matrix_synapse_database_host: "your-postgres-server-hostname"
matrix_synapse_database_user: "your-postgres-server-username"
matrix_synapse_database_password: "your-postgres-server-password"
matrix_synapse_database_database: "your-postgres-server-database-name"
```

The database (as specified in `matrix_synapse_database_database`) must exist and be accessible with the given credentials.
It must be empty or contain a valid Synapse database. If empty, Synapse would populate it the first time it runs.

**Note**: the external server that you specify in `matrix_synapse_database_host` must be accessible from within the `matrix-synapse` Docker container (and possibly other containers too). This means that it either needs to be a publicly accessible hostname or that it's a hostname on the same Docker network where all containers installed by this playbook run (a network called `matrix` by default). Using a local PostgreSQL instance on the host (running on the same machine, but not in a container) is not possible.

The connection to your external Postgres server **will not be SSL encrypted**, as [we don't support that yet](https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/89).