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

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---
type: reference
---
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# Working with the bundled PgBouncer service **(PREMIUM ONLY)**
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As part of its High Availability stack, GitLab Premium includes a bundled version of [PgBouncer](http://www.pgbouncer.org/) that can be managed through `/etc/gitlab/gitlab.rb`. 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.
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In a HA setup, it's recommended to run a PgBouncer node separately for each database node with an internal load balancer (TCP) serving each accordingly.
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## Operations
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### Running PgBouncer as part of an HA GitLab installation
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1. Make sure you collect [`CONSUL_SERVER_NODES`](database.md#consul-information), [`CONSUL_PASSWORD_HASH`](database.md#consul-information), and [`PGBOUNCER_PASSWORD_HASH`](database.md#pgbouncer-information) before executing the next step.
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1. One each node, edit the `/etc/gitlab/gitlab.rb` config file and replace values noted in the `# START user configuration` section as below:
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```ruby
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# Disable all components except PgBouncer and Consul agent
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roles ['pgbouncer_role']
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# Configure PgBouncer
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pgbouncer['admin_users'] = %w(pgbouncer gitlab-consul)
# Configure Consul agent
consul['watchers'] = %w(postgresql)
# START user configuration
# Please set the real values as explained in Required Information section
# Replace CONSUL_PASSWORD_HASH with with a generated md5 value
# Replace PGBOUNCER_PASSWORD_HASH with with a generated md5 value
pgbouncer['users'] = {
'gitlab-consul': {
password: 'CONSUL_PASSWORD_HASH'
},
'pgbouncer': {
password: 'PGBOUNCER_PASSWORD_HASH'
}
}
# Replace placeholders:
#
# Y.Y.Y.Y consul1.gitlab.example.com Z.Z.Z.Z
# with the addresses gathered for CONSUL_SERVER_NODES
consul['configuration'] = {
retry_join: %w(Y.Y.Y.Y consul1.gitlab.example.com Z.Z.Z.Z)
}
#
# END user configuration
```
NOTE: **Note:**
`pgbouncer_role` was introduced with GitLab 10.3.
1. Run `gitlab-ctl reconfigure`
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1. Create a `.pgpass` file so Consul is able to
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reload PgBouncer. Enter the `PGBOUNCER_PASSWORD` twice when asked:
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```shell
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gitlab-ctl write-pgpass --host 127.0.0.1 --database pgbouncer --user pgbouncer --hostuser gitlab-consul
```
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#### PgBouncer Checkpoint
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1. Ensure each node is talking to the current master:
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```shell
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gitlab-ctl pgb-console # You will be prompted for PGBOUNCER_PASSWORD
```
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If there is an error `psql: ERROR: Auth failed` after typing in the
password, ensure you previously generated the MD5 password hashes with the correct
format. The correct format is to concatenate the password and the username:
`PASSWORDUSERNAME`. For example, `Sup3rS3cr3tpgbouncer` would be the text
needed to generate an MD5 password hash for the `pgbouncer` user.
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1. Once the console prompt is available, run the following queries:
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```shell
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show databases ; show clients ;
```
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The output should be similar to the following:
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```plaintext
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name | host | port | database | force_user | pool_size | reserve_pool | pool_mode | max_connections | current_connections
---------------------+-------------+------+---------------------+------------+-----------+--------------+-----------+-----------------+---------------------
gitlabhq_production | MASTER_HOST | 5432 | gitlabhq_production | | 20 | 0 | | 0 | 0
pgbouncer | | 6432 | pgbouncer | pgbouncer | 2 | 0 | statement | 0 | 0
(2 rows)
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type | user | database | state | addr | port | local_addr | local_port | connect_time | request_time | ptr | link | remote_pid | tls
------+-----------+---------------------+---------+----------------+-------+------------+------------+---------------------+---------------------+-----------+------+------------+-----
C | pgbouncer | pgbouncer | active | 127.0.0.1 | 56846 | 127.0.0.1 | 6432 | 2017-08-21 18:09:59 | 2017-08-21 18:10:48 | 0x22b3880 | | 0 |
(2 rows)
```
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#### Configure the internal load balancer
If you're running more than one PgBouncer node as recommended, then at this time you'll need to set up a TCP internal load balancer to serve each correctly. This can be done with any reputable TCP load balancer.
As an example here's how you could do it with [HAProxy](https://www.haproxy.org/):
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```plaintext
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global
log /dev/log local0
log localhost local1 notice
log stdout format raw local0
defaults
log global
default-server inter 10s fall 3 rise 2
balance leastconn
frontend internal-pgbouncer-tcp-in
bind *:6432
mode tcp
option tcplog
default_backend pgbouncer
backend pgbouncer
mode tcp
option tcp-check
server pgbouncer1 <ip>:6432 check
server pgbouncer2 <ip>:6432 check
server pgbouncer3 <ip>:6432 check
```
Refer to your preferred Load Balancer's documentation for further guidance.
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### Running PgBouncer as part of a non-HA GitLab installation
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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`
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```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
```
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1. Run `gitlab-ctl reconfigure`
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**Note:** If the database was already running, it will need to be restarted after reconfigure by running `gitlab-ctl restart postgresql`.
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1. On the node you are running PgBouncer on, make sure the following is set in `/etc/gitlab/gitlab.rb`
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```ruby
pgbouncer['enable'] = true
pgbouncer['databases'] = {
gitlabhq_production: {
host: 'DATABASE_HOST',
user: 'pgbouncer',
password: 'PGBOUNCER_USER_PASSWORD_HASH'
}
}
```
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1. Run `gitlab-ctl reconfigure`
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1. On the node running Puma, make sure the following is set in `/etc/gitlab/gitlab.rb`
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```ruby
gitlab_rails['db_host'] = 'PGBOUNCER_HOST'
gitlab_rails['db_port'] = '6432'
gitlab_rails['db_password'] = 'SQL_USER_PASSWORD'
```
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1. Run `gitlab-ctl reconfigure`
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1. At this point, your instance should connect to the database through PgBouncer. If you are having issues, see the [Troubleshooting](#troubleshooting) section
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## Enable Monitoring
> [Introduced](https://gitlab.com/gitlab-org/omnibus-gitlab/issues/3786) in GitLab 12.0.
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If you enable Monitoring, it must be enabled on **all** PgBouncer servers.
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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.
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### Interacting with PgBouncer
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#### Administrative console
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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://www.pgbouncer.org/usage.html#admin-console) for detailed instructions on how to interact with the console.
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To start a session, run
```shell
# gitlab-ctl pgb-console
Password for user pgbouncer:
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psql (11.7, server 1.7.2/bouncer)
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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
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```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
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In case you are experiencing any issues connecting through PgBouncer, the first place to check is always the logs:
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```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.
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### 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).