Supported tags and respective
What is PostgreSQL?
PostgreSQL, often simply “Postgres”, is an object-relational database management system (ORDBMS) with an emphasis on extensibility and standards-compliance. As a database server, its primary function is to store data, securely and supporting best practices, and retrieve it later, as requested by other software applications, be it those on the same computer or those running on another computer across a network (including the Internet). It can handle workloads ranging from small single-machine applications to large Internet-facing applications with many concurrent users. Recent versions also provide replication of the database itself for security and scalability.
PostgreSQL implements the majority of the SQL:2011 standard, is ACID-compliant and transactional (including most DDL statements) avoiding locking issues using multiversion concurrency control (MVCC), provides immunity to dirty reads and full serializability; handles complex SQL queries using many indexing methods that are not available in other databases; has updateable views and materialized views, triggers, foreign keys; supports functions and stored procedures, and other expandability, and has a large number of extensions written by third parties. In addition to the possibility of working with the major proprietary and open source databases, PostgreSQL supports migration from them, by its extensive standard SQL support and available migration tools. And if proprietary extensions had been used, by its extensibility that can emulate many through some built-in and third-party open source compatibility extensions, such as for Oracle.
How to use this image
start a postgres instance
docker run --name some-postgres -e POSTGRES_PASSWORD=mysecretpassword -d postgres
This image includes
EXPOSE 5432 (the postgres port), so standard container linking will make it automatically available to the linked containers. The default
postgres user and database are created in the entrypoint with
The postgres database is a default database meant for use by users, utilities and third party applications.
connect to it from an application
docker run --name some-app --link some-postgres:postgres -d application-that-uses-postgres
… or via
docker run -it --link some-postgres:postgres --rm postgres sh -c 'exec psql -h "$POSTGRES_PORT_5432_TCP_ADDR" -p "$POSTGRES_PORT_5432_TCP_PORT" -U postgres'
The PostgreSQL image uses several environment variables which are easy to miss. While none of the variables are required, they may significantly aid you in using the image.
This environment variable is recommend for you to use the PostgreSQL image. This environment variable sets the superuser password for PostgreSQL. The default superuser is defined by the
POSTGRES_USER environment variable. In the above example, it is being set to “mysecretpassword”.
This optional environment variable is used in conjunction with
POSTGRES_PASSWORD to set a user and its password. This variable will create the specified user with superuser power and a database with the same name. If it is not specified, then the default user of
postgres will be used.
How to extend this image
If you would like to do additional initialization in an image derived from this one, add a
*.sh script under
/docker-entrypoint-initdb.d (creating the directory if necessary). After the entrypoint calls
initdb to create the default
postgres user and database, it will source any
*.sh script found in that directory to do further initialization before starting the service. If you need to execute SQL commands as part of your initialization, the use of Postgres'' single user mode is highly recommended.
You can also extend the image with a simple
Dockerfile to set the locale. The following example will set the default locale to
FROM postgres:9.4 RUN localedef -i de_DE -c -f UTF-8 -A /usr/share/locale/locale.alias de_DE.UTF-8 ENV LANG de_DE.utf8
Since database initialization only happens on container startup, this allows us to set the language before it is created.
If there is no database when
postgres starts in a container, then
postgres will create the default database for you. While this is the expected behavior of
postgres, this means that it will not accept incoming connections during that time. This may cause issues when using automation tools, such as
fig, that start several containers simultaneously.
Supported Docker versions
This image is officially supported on Docker version 1.7.0.
Support for older versions (down to 1.0) is provided on a best-effort basis.
Documentation for this image is stored in the
postgres/ directory of the
docker-library/docs GitHub repo. Be sure to familiarize yourself with the repository's
README.md file before attempting a pull request.
You can also reach many of the official image maintainers via the
#docker-library IRC channel on Freenode.
You are invited to contribute new features, fixes, or updates, large or small; we are always thrilled to receive pull requests, and do our best to process them as fast as we can.
Before you start to code, we recommend discussing your plans on the mailing list or through a GitHub issue, especially for more ambitious contributions. This gives other contributors a chance to point you in the right direction, give you feedback on your design, and help you find out if someone else is working on the same thing.