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docker-mariadb

A Dockerfile that produces a container that will run MariaDB 5.5, a drop-in replacement for MySQL.

Image Creation

This example creates the image with the tag paintedfox/mariadb, but you can change this to use your own username.

$ docker build -t="paintedfox/mariadb" .

Alternately, you can run the following if you have make installed...

$ make

You can also specify a custom docker username like so:

$ make DOCKER_USER=paintedfox

Container Creation / Running

The MariaDB server is configured to store data in /data inside the container. You can map the container's /data volume to a volume on the host so the data becomes independant of the running container.

This example uses /tmp/mariadb to store the MariaDB data, but you can modify this to your needs.

When the container runs, it creates a superuser with a random password. You can set the username and password for the superuser by setting the container's environment variables. This lets you discover the username and password of the superuser from within a linked container or from the output of docker inspect mariadb.

$ mkdir -p /tmp/mariadb
$ docker run -d -name="mariadb" \
             -p 127.0.0.1:3306:3306 \
             -v /tmp/mariadb:/data \
             -e USER="super" \
             -e PASS="$(pwgen -s -1 16)" \
             paintedfox/mariadb

Alternately, you can run the following if you have make installed...

$ make run

You can also specify a custom port to bind to on the host, a custom data directory, and the superuser username and password on the host like so:

$ sudo mkdir -p /srv/docker/mariadb
$ make run PORT=127.0.0.1:3306 \
           DATA_DIR=/srv/docker/mariadb \
           USER=super \
           PASS=$(pwgen -s -1 16)

Connecting to the Database

To connect to the MariaDB server, you will need to make sure you have a client. You can install the mysql-client on your host machine by running the following (Ubuntu 12.04LTS):

$ sudo apt-get install mysql-client

As part of the startup for MariaDB, the container will generate a random password for the superuser. To view the login in run docker logs <container_name> like so:

$ docker logs mariadb
MARIADB_USER=super
MARIADB_PASS=FzNQiroBkTHLX7y4
MARIADB_DATA_DIR=/data
Starting MariaDB...
140103 20:33:49 mysqld_safe Logging to '/data/mysql.log'.
140103 20:33:49 mysqld_safe Starting mysqld daemon with databases from /data

Then you can connect to the MariaDB server from the host with the following command:

$ mysql -u super --password=FzNQiroBkTHLX7y4 --protocol=tcp

Linking with the Database Container

You can link a container to the database container. You may want to do this to keep web application processes that need to connect to the database in a separate container.

To demonstrate this, we can spin up a new container like so:

$ docker run -t -i -link mariadb:db ubuntu bash

This assumes you're already running the database container with the name mariadb. The -link mariadb:db will give the linked container the alias db inside of the new container.

From the new container you can connect to the database by running the following commands:

$ apt-get install -y mysql-client
$ mysql -u "$DB_ENV_USER" --password="$DB_ENV_PASS" -h "$DB_PORT_3306_TCP_ADDR" -P "$DB_PORT_3306_TCP_PORT"

If you ran the mariadb container with the flags -e USER=<user> and -e PASS=<pass>, then the linked container should have these variables available in its environment. Since we aliased the database container with the name db, the environment variables from the database container are copied into the linked container with the prefix DB_ENV_.