## Enable FDW support for the Geo Tracking Database (improves performance)
##
geo_secondary['db_fdw'] = true
```
For external PostgreSQL instances, see [additional instructions](external_database.md).
If you bring a former **primary** node back online to serve as a **secondary** node, then you also need to remove `roles ['geo_primary_role']` or `geo_primary_role['enable'] = true`.
1. Reconfigure GitLab for the changes to take effect:
```sh
gitlab-ctl reconfigure
```
1. Restart PostgreSQL for the IP change to take effect and reconfigure again:
```sh
gitlab-ctl restart postgresql
gitlab-ctl reconfigure
```
This last reconfigure will provision the FDW configuration and enable it.
### Step 3. Initiate the replication process
Below we provide a script that connects the database on the **secondary** node to
the database on the **primary** node, replicates the database, and creates the
needed files for streaming replication.
The directories used are the defaults that are set up in Omnibus. If you have
Make sure to run this on the **secondary** server as it removes all PostgreSQL's
data before running `pg_basebackup`.
1. SSH into your GitLab **secondary** server and login as root:
```sh
sudo -i
```
1. Choose a database-friendly name to use for your **secondary** node to
use as the replication slot name. For example, if your domain is
`secondary.geo.example.com`, you may use `secondary_example` as the slot
name as shown in the commands below.
1. Execute the command below to start a backup/restore and begin the replication
CAUTION: **Warning:** Each Geo **secondary** node must have its own unique replication slot name.
Using the same slot name between two secondaries will break PostgreSQL replication.
```sh
gitlab-ctl replicate-geo-database \
--slot-name=<secondary_node_name> \
--host=<primary_node_ip>
```
When prompted, enter the _plaintext_ password you set up for the `gitlab_replicator`
user in the first step.
This command also takes a number of additional options. You can use `--help`
to list them all, but here are a couple of tips:
- If PostgreSQL is listening on a non-standard port, add `--port=` as well.
- If your database is too large to be transferred in 30 minutes, you will need
to increase the timeout, e.g., `--backup-timeout=3600` if you expect the
initial replication to take under an hour.
- Pass `--sslmode=disable` to skip PostgreSQL TLS authentication altogether
(e.g., you know the network path is secure, or you are using a site-to-site
VPN). This is **not** safe over the public Internet!
- You can read more details about each `sslmode` in the
[PostgreSQL documentation][pg-docs-ssl];
the instructions above are carefully written to ensure protection against
both passive eavesdroppers and active "man-in-the-middle" attackers.
- Change the `--slot-name` to the name of the replication slot
to be used on the **primary** database. The script will attempt to create the
replication slot automatically if it does not exist.
- If you're repurposing an old server into a Geo **secondary** node, you'll need to
add `--force` to the command line.
- When not in a production machine you can disable backup step if you
really sure this is what you want by adding `--skip-backup`
The replication process is now complete.
## PGBouncer support (optional)
[PGBouncer](http://pgbouncer.github.io/) may be used with GitLab Geo to pool
PostgreSQL connections. We recommend using PGBouncer if you use GitLab in a
high-availability configuration with a cluster of nodes supporting a Geo
**primary** node and another cluster of nodes supporting a Geo **secondary** node. For more
information, see the [Omnibus HA](https://docs.gitlab.com/ee/administration/high_availability/database.html#configure-using-omnibus-for-high-availability)
documentation.
For a Geo **secondary** node to work properly with PGBouncer in front of the database,
it will need a separate read-only user to make [PostgreSQL FDW queries][FDW]
work:
1. On the **primary** Geo database, enter the PostgreSQL on the console as an
admin user. If you are using an Omnibus-managed database, log onto the **primary**
node that is running the PostgreSQL database (the default Omnibus database name is gitlabhq_production):
```sh
sudo \
-u gitlab-psql /opt/gitlab/embedded/bin/psql \
-h /var/opt/gitlab/postgresql gitlabhq_production
```
1. Then create the read-only user:
```sql
-- NOTE: Use the password defined earlier
CREATE USER gitlab_geo_fdw WITH password 'mypassword';
GRANT CONNECT ON DATABASE gitlabhq_production to gitlab_geo_fdw;
GRANT USAGE ON SCHEMA public TO gitlab_geo_fdw;
GRANT SELECT ON ALL TABLES IN SCHEMA public TO gitlab_geo_fdw;
GRANT SELECT ON ALL SEQUENCES IN SCHEMA public TO gitlab_geo_fdw;
-- Tables created by "gitlab" should be made read-only for "gitlab_geo_fdw"
-- automatically.
ALTER DEFAULT PRIVILEGES FOR USER gitlab IN SCHEMA public GRANT SELECT ON TABLES TO gitlab_geo_fdw;
ALTER DEFAULT PRIVILEGES FOR USER gitlab IN SCHEMA public GRANT SELECT ON SEQUENCES TO gitlab_geo_fdw;
```
1. On the **secondary** nodes, change `/etc/gitlab/gitlab.rb`:
