# 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.