pgBouncer is a lightweight connection pooler for PostgreSQL databases.


The following features are supported by the crunchy-pgbouncer container:

  • crunchy-pgbouncer uses auth_query to authenticate users. This requires the pgbouncer username and password in users.txt. Automatically generated from environment variables, see Restrictions.
  • Mount a custom users.txt and pgbouncer.ini configurations for advanced usage.
  • Tune pooling parameters via environment variables.
  • Connect to the administration database in pgBouncer to view statistics of the target databases.


The crunchy-pgbouncer Docker image contains the following packages (versions vary depending on PostgreSQL version):

  • PostgreSQL (15.2, 14.7, 13.10, 12.14 and 11.19)
  • pgBouncer
  • UBI 8 - publicly available
  • UBI 8 - customers only


  • OpenShift: If custom configurations aren’t being mounted, an emptydir volume is required to be mounted at /pgconf.
  • Superusers cannot connect through the connection pooler.
  • User is required to configure the database for auth_query, see pgbouncer.ini file for configuration details.

Environment Variables


Name Default Description
PGBOUNCER_PASSWORD None The password of the pgBouncer role in PostgreSQL. Must be also set on the primary database.
PG_SERVICE None The hostname of the database service.


Name Default Description
DEFAULT_POOL_SIZE 20 How many server connections to allow per user/database pair.
MAX_CLIENT_CONN 100 Maximum number of client connections allowed.
MAX_DB_CONNECTIONS Unlimited Do not allow more than this many connections per-database.
MIN_POOL_SIZE 0 Adds more server connections to pool if below this number.
POOL_MODE Session When a server connection can be reused by other clients. Possible values: session, transaction and statement.
RESERVE_POOL_SIZE 0 How many additional connections to allow per pool. 0 disables.
RESERVE_POOL_TIMEOUT 5 If a client has not been serviced in this many seconds, pgbouncer enables use of additional connections from reserve pool. 0 disables.
QUERY_TIMEOUT 0 Queries running longer than that are canceled.
IGNORE_STARTUP_PARAMETERS extra_float_digits Set to ignore particular parameters in startup packets.
PG_PORT 5432 The port to use when connecting to the database.
CRUNCHY_DEBUG FALSE Set this to true to enable debugging in logs. Note: this mode can reveal secrets in logs.