pgbouncer is a popular, small connection pooler for Postgresql. This is yet another docker image with pgbouncer, based on alpine.
You can configure it by Environment variables:
$ docker run -d \ --name=pgbouncer \ -e DB_HOST=postgresql.example.com \ -e DB_USER=admin \ -e DB_PASSWORD=mypassword \ brainsam/pgbouncer:latest
Or You can mount config file into docker container:
$ docker run -d \ --name pgbouncer \ -v pgbouncer-config-file:/etc/pgbouncer/pgbouncer.ini \ brainsam/pgbouncer:latest
$ docker pull brainsam/pgbouncer:latest
All configuration parameters of pgbouncer are available both by --env (use the same keys in upper case) and by mounting pgbouncer.ini into container.
docker logs <your-pgbouncer-container-name>