debian-mirror-gitlab/doc/administration/postgresql/pgbouncer.md

---
stage: Enablement
group: Database
info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
type: reference
---

# Working with the bundled PgBouncer service **(PREMIUM SELF)**

[PgBouncer](http://www.pgbouncer.org/) is used to seamlessly migrate database
connections between servers in a failover scenario. Additionally, it can be used
in a non-fault-tolerant setup to pool connections, speeding up response time
while reducing resource usage.

GitLab Premium includes a bundled version of PgBouncer that can be managed
through `/etc/gitlab/gitlab.rb`.

## PgBouncer as part of a fault-tolerant GitLab installation

This content has been moved to a [new location](replication_and_failover.md#configuring-the-pgbouncer-node).

## PgBouncer as part of a non-fault-tolerant GitLab installation

1. Generate PGBOUNCER_USER_PASSWORD_HASH with the command `gitlab-ctl pg-password-md5 pgbouncer`

1. Generate SQL_USER_PASSWORD_HASH with the command `gitlab-ctl pg-password-md5 gitlab`. We'll also need to enter the plaintext SQL_USER_PASSWORD later

1. On your database node, ensure the following is set in your `/etc/gitlab/gitlab.rb`

   ```ruby
   postgresql['pgbouncer_user_password'] = 'PGBOUNCER_USER_PASSWORD_HASH'
   postgresql['sql_user_password'] = 'SQL_USER_PASSWORD_HASH'
   postgresql['listen_address'] = 'XX.XX.XX.Y' # Where XX.XX.XX.Y is the ip address on the node postgresql should listen on
   postgresql['md5_auth_cidr_addresses'] = %w(AA.AA.AA.B/32) # Where AA.AA.AA.B is the IP address of the pgbouncer node
   ```

1. Run `gitlab-ctl reconfigure`

   NOTE:
   If the database was already running, it will need to be restarted after reconfigure by running `gitlab-ctl restart postgresql`.

1. On the node you are running PgBouncer on, make sure the following is set in `/etc/gitlab/gitlab.rb`

   ```ruby
   pgbouncer['enable'] = true
   pgbouncer['databases'] = {
     gitlabhq_production: {
       host: 'DATABASE_HOST',
       user: 'pgbouncer',
       password: 'PGBOUNCER_USER_PASSWORD_HASH'
     }
   }
   ```

1. Run `gitlab-ctl reconfigure`

1. On the node running Puma, make sure the following is set in `/etc/gitlab/gitlab.rb`

   ```ruby
   gitlab_rails['db_host'] = 'PGBOUNCER_HOST'
   gitlab_rails['db_port'] = '6432'
   gitlab_rails['db_password'] = 'SQL_USER_PASSWORD'
   ```

1. Run `gitlab-ctl reconfigure`

1. At this point, your instance should connect to the database through PgBouncer. If you are having issues, see the [Troubleshooting](#troubleshooting) section

## Backups

Do not backup or restore GitLab through a PgBouncer connection: this will cause a GitLab outage.

[Read more about this and how to reconfigure backups](../../raketasks/backup_restore.md#backup-and-restore-for-installations-using-pgbouncer).

## Enable Monitoring

> [Introduced](https://gitlab.com/gitlab-org/omnibus-gitlab/-/issues/3786) in GitLab 12.0.

If you enable Monitoring, it must be enabled on **all** PgBouncer servers.

1. Create/edit `/etc/gitlab/gitlab.rb` and add the following configuration:

   ```ruby
   # Enable service discovery for Prometheus
   consul['enable'] = true
   consul['monitoring_service_discovery'] =  true

   # Replace placeholders
   # Y.Y.Y.Y consul1.gitlab.example.com Z.Z.Z.Z
   # with the addresses of the Consul server nodes
   consul['configuration'] = {
      retry_join: %w(Y.Y.Y.Y consul1.gitlab.example.com Z.Z.Z.Z),
   }

   # Set the network addresses that the exporters will listen on
   node_exporter['listen_address'] = '0.0.0.0:9100'
   pgbouncer_exporter['listen_address'] = '0.0.0.0:9188'
   ```

1. Run `sudo gitlab-ctl reconfigure` to compile the configuration.

## Administrative console

As part of Omnibus GitLab, a command is provided to automatically connect to the
PgBouncer administrative console. See the
[PgBouncer documentation](https://www.pgbouncer.org/usage.html#admin-console)
for detailed instructions on how to interact with the console.

To start a session run the following and provide the password for the `pgbouncer`
user:

```shell
sudo gitlab-ctl pgb-console
```

To get some basic information about the instance:

```shell
pgbouncer=# show databases; show clients; show servers;
        name         |   host    | port |      database       | force_user | pool_size | reserve_pool | pool_mode | max_connections | current_connections
---------------------+-----------+------+---------------------+------------+-----------+--------------+-----------+-----------------+---------------------
 gitlabhq_production | 127.0.0.1 | 5432 | gitlabhq_production |            |       100 |            5 |           |               0 |                   1
 pgbouncer           |           | 6432 | pgbouncer           | pgbouncer  |         2 |            0 | statement |               0 |                   0
(2 rows)

 type |   user    |      database       | state  |   addr    | port  | local_addr | local_port |    connect_time     |    request_time     |    ptr    | link
| remote_pid | tls
------+-----------+---------------------+--------+-----------+-------+------------+------------+---------------------+---------------------+-----------+------
+------------+-----
 C    | gitlab    | gitlabhq_production | active | 127.0.0.1 | 44590 | 127.0.0.1  |       6432 | 2018-04-24 22:13:10 | 2018-04-24 22:17:10 | 0x12444c0 |
|          0 |
 C    | gitlab    | gitlabhq_production | active | 127.0.0.1 | 44592 | 127.0.0.1  |       6432 | 2018-04-24 22:13:10 | 2018-04-24 22:17:10 | 0x12447c0 |
|          0 |
 C    | gitlab    | gitlabhq_production | active | 127.0.0.1 | 44594 | 127.0.0.1  |       6432 | 2018-04-24 22:13:10 | 2018-04-24 22:17:10 | 0x1244940 |
|          0 |
 C    | gitlab    | gitlabhq_production | active | 127.0.0.1 | 44706 | 127.0.0.1  |       6432 | 2018-04-24 22:14:22 | 2018-04-24 22:16:31 | 0x1244ac0 |
|          0 |
 C    | gitlab    | gitlabhq_production | active | 127.0.0.1 | 44708 | 127.0.0.1  |       6432 | 2018-04-24 22:14:22 | 2018-04-24 22:15:15 | 0x1244c40 |
|          0 |
 C    | gitlab    | gitlabhq_production | active | 127.0.0.1 | 44794 | 127.0.0.1  |       6432 | 2018-04-24 22:15:15 | 2018-04-24 22:15:15 | 0x1244dc0 |
|          0 |
 C    | gitlab    | gitlabhq_production | active | 127.0.0.1 | 44798 | 127.0.0.1  |       6432 | 2018-04-24 22:15:15 | 2018-04-24 22:16:31 | 0x1244f40 |
|          0 |
 C    | pgbouncer | pgbouncer           | active | 127.0.0.1 | 44660 | 127.0.0.1  |       6432 | 2018-04-24 22:13:51 | 2018-04-24 22:17:12 | 0x1244640 |
|          0 |
(8 rows)

 type |  user  |      database       | state |   addr    | port | local_addr | local_port |    connect_time     |    request_time     |    ptr    | link | rem
ote_pid | tls
------+--------+---------------------+-------+-----------+------+------------+------------+---------------------+---------------------+-----------+------+----
--------+-----
 S    | gitlab | gitlabhq_production | idle  | 127.0.0.1 | 5432 | 127.0.0.1  |      35646 | 2018-04-24 22:15:15 | 2018-04-24 22:17:10 | 0x124dca0 |      |
  19980 |
(1 row)
```

## Procedure for bypassing PgBouncer

Some database changes have to be done directly, and not through PgBouncer.

Read more about the affected tasks: [database restores](../../raketasks/backup_restore.md#backup-and-restore-for-installations-using-pgbouncer)
and [GitLab upgrades](https://docs.gitlab.com/omnibus/update/README.html#use-postgresql-ha).

1. To find the primary node, run the following on a database node:

   ```shell
   sudo gitlab-ctl repmgr cluster show
   ```

1. Edit `/etc/gitlab/gitlab.rb` on the application node you're performing the task on, and update
   `gitlab_rails['db_host']` and `gitlab_rails['db_port']` with the database
   primary's host and port.

1. Run reconfigure:

   ```shell
   sudo gitlab-ctl reconfigure
   ```

Once you've performed the tasks or procedure, switch back to using PgBouncer:

1. Change back `/etc/gitlab/gitlab.rb` to point to PgBouncer.
1. Run reconfigure:

   ```shell
   sudo gitlab-ctl reconfigure
   ```

## Troubleshooting

In case you are experiencing any issues connecting through PgBouncer, the first
place to check is always the logs:

```shell
sudo gitlab-ctl tail pgbouncer
```

Additionally, you can check the output from `show databases` in the
[administrative console](#administrative-console). In the output, you would expect
to see values in the `host` field for the `gitlabhq_production` database.
Additionally, `current_connections` should be greater than 1.

### Message: `LOG:  invalid CIDR mask in address`

See the suggested fix [in Geo documentation](../geo/replication/troubleshooting.md#message-log--invalid-cidr-mask-in-address).

### Message: `LOG:  invalid IP mask "md5": Name or service not known`

See the suggested fix [in Geo documentation](../geo/replication/troubleshooting.md#message-log--invalid-ip-mask-md5-name-or-service-not-known).