# Working with the bundle Pgbouncer service
## Overview
As part of its High Availability stack, GitLab Premium includes a bundled version of [Pgbouncer](https://pgbouncer.github.io/) that can be managed through `/etc/gitlab/gitlab.rb`.
In a High Availability setup, Pgbouncer is used to seamlessly migrate database connections between servers in a failover scenario.
Additionally, it can be used in a non-HA setup to pool connections, speeding up response time while reducing resource usage.
It is recommended to run pgbouncer alongside the `gitlab-rails` service, or on its own dedicated node in a cluster.
## Operations
### Running Pgbouncer as part of an HA GitLab installation
See our [HA documentation for PostgreSQL](database.md) for information on running pgbouncer as part of a HA setup
### Running Pgbouncer as part of a non-HA 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 unicorn, 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
### Interacting with pgbouncer
#### Administrative console
As part of omnibus-gitlab, we provide a command `gitlab-ctl pgb-console` to automatically connect to the pgbouncer administrative console. Please see the [pgbouncer documentation](https://pgbouncer.github.io/usage.html#admin-console) for detailed instructions on how to interact with the console.
To start a session, run
```shell
# gitlab-ctl pgb-console
Password for user pgbouncer:
psql (9.6.8, server 1.7.2/bouncer)
Type "help" for help.
pgbouncer=#
```
The password you will be prompted for is the PGBOUNCER_USER_PASSWORD
To get some basic information about the instance, run
```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)
```
## Troubleshooting
In case you are experiencing any issues connecting through pgbouncer, the first place to check is always the logs:
```shell
# 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.