page_title: PostgreSQL service How-To
page_description: Running and installing a PostgreSQL service
page_keywords: docker, example, package installation, postgresql

# PostgreSQL Service

> **Note**: 
> 
> - This example assumes you have Docker running in daemon mode. For
>   more information please see [*Check your Docker
>   install*](../hello_world/#running-examples).
> - **If you don't like sudo** then see [*Giving non-root
>   access*](/installation/binaries/#dockergroup)

## Installing PostgreSQL on Docker

Assuming there is no Docker image that suits your needs in [the index](
http://index.docker.io), you can create one yourself.

Start by creating a new Dockerfile:

> **Note**: 
> This PostgreSQL setup is for development only purposes. Refer to the
> PostgreSQL documentation to fine-tune these settings so that it is
> suitably secure.

    #
    # example Dockerfile for http://docs.docker.io/examples/postgresql_service/
    #

    FROM ubuntu
    MAINTAINER SvenDowideit@docker.com

    # Add the PostgreSQL PGP key to verify their Debian packages.
    # It should be the same key as https://www.postgresql.org/media/keys/ACCC4CF8.asc 
    RUN apt-key adv --keyserver keyserver.ubuntu.com --recv-keys B97B0AFCAA1A47F044F244A07FCC7D46ACCC4CF8

    # Add PostgreSQL's repository. It contains the most recent stable release
    #     of PostgreSQL, ``9.3``.
    RUN echo "deb http://apt.postgresql.org/pub/repos/apt/ precise-pgdg main" > /etc/apt/sources.list.d/pgdg.list

    # Update the Ubuntu and PostgreSQL repository indexes
    RUN apt-get update

    # Install ``python-software-properties``, ``software-properties-common`` and PostgreSQL 9.3
    #  There are some warnings (in red) that show up during the build. You can hide
    #  them by prefixing each apt-get statement with DEBIAN_FRONTEND=noninteractive
    RUN apt-get -y -q install python-software-properties software-properties-common
    RUN apt-get -y -q install postgresql-9.3 postgresql-client-9.3 postgresql-contrib-9.3

    # Note: The official Debian and Ubuntu images automatically ``apt-get clean``
    # after each ``apt-get`` 

    # Run the rest of the commands as the ``postgres`` user created by the ``postgres-9.3`` package when it was ``apt-get installed``
    USER postgres

    # Create a PostgreSQL role named ``docker`` with ``docker`` as the password and
    # then create a database `docker` owned by the ``docker`` role.
    # Note: here we use ``&&\`` to run commands one after the other - the ``\``
    #       allows the RUN command to span multiple lines.
    RUN    /etc/init.d/postgresql start &&\
        psql --command "CREATE USER docker WITH SUPERUSER PASSWORD 'docker';" &&\
        createdb -O docker docker

    # Adjust PostgreSQL configuration so that remote connections to the
    # database are possible. 
    RUN echo "host all  all    0.0.0.0/0  md5" >> /etc/postgresql/9.3/main/pg_hba.conf

    # And add ``listen_addresses`` to ``/etc/postgresql/9.3/main/postgresql.conf``
    RUN echo "listen_addresses='*'" >> /etc/postgresql/9.3/main/postgresql.conf

    # Expose the PostgreSQL port
    EXPOSE 5432

    # Add VOLUMEs to allow backup of config, logs and databases
    VOLUME  ["/etc/postgresql", "/var/log/postgresql", "/var/lib/postgresql"]

    # Set the default command to run when starting the container
    CMD ["/usr/lib/postgresql/9.3/bin/postgres", "-D", "/var/lib/postgresql/9.3/main", "-c", "config_file=/etc/postgresql/9.3/main/postgresql.conf"]

Build an image from the Dockerfile assign it a name.

    $ sudo docker build -t eg_postgresql .

And run the PostgreSQL server container (in the foreground):

    $ sudo docker run --rm -P --name pg_test eg_postgresql

There are 2 ways to connect to the PostgreSQL server. We can use [*Link
Containers*](/use/working_with_links_names/#working-with-links-names),
or we can access it from our host (or the network).

> **Note**: 
> The `-rm` removes the container and its image when
> the container exists successfully.

### Using container linking

Containers can be linked to another container's ports directly using
`-link remote_name:local_alias` in the client's
`docker run`. This will set a number of environment
variables that can then be used to connect:

    $ sudo docker run --rm -t -i --link pg_test:pg eg_postgresql bash

    postgres@7ef98b1b7243:/$ psql -h $PG_PORT_5432_TCP_ADDR -p $PG_PORT_5432_TCP_PORT -d docker -U docker --password

### Connecting from your host system

Assuming you have the postgresql-client installed, you can use the
host-mapped port to test as well. You need to use `docker ps`
to find out what local host port the container is mapped to
first:

    $ docker ps
    CONTAINER ID        IMAGE                  COMMAND                CREATED             STATUS              PORTS                                      NAMES
    5e24362f27f6        eg_postgresql:latest   /usr/lib/postgresql/   About an hour ago   Up About an hour    0.0.0.0:49153->5432/tcp                    pg_test
    $ psql -h localhost -p 49153 -d docker -U docker --password

### Testing the database

Once you have authenticated and have a `docker =#`
prompt, you can create a table and populate it.

    psql (9.3.1)
    Type "help" for help.

    $ docker=# CREATE TABLE cities (
    docker(#     name            varchar(80),
    docker(#     location        point
    docker(# );
    CREATE TABLE
    $ docker=# INSERT INTO cities VALUES ('San Francisco', '(-194.0, 53.0)');
    INSERT 0 1
    $ docker=# select * from cities;
         name      | location
    ---------------+-----------
     San Francisco | (-194,53)
    (1 row)

### Using the container volumes

You can use the defined volumes to inspect the PostgreSQL log files and
to backup your configuration and data:

    $ docker run --rm --volumes-from pg_test -t -i busybox sh

    / # ls
    bin      etc      lib      linuxrc  mnt      proc     run      sys      usr
    dev      home     lib64    media    opt      root     sbin     tmp      var
    / # ls /etc/postgresql/9.3/main/
    environment      pg_hba.conf      postgresql.conf
    pg_ctl.conf      pg_ident.conf    start.conf
    /tmp # ls /var/log
    ldconfig    postgresql
