docker-mariadb is a CentOS-based Docker image for MariaDB containers.

Getting the image

This image is published in the Docker Hub. Simply run the below command to get it on your machine:

docker pull dylanlindgren/docker-mariadb

Understanding the image

This image adheres to the principle of having a Docker container for each process.

All data is redirected to the /data/mariadb/data location and when this is mapped to the host using the -v switch then the container is completely disposable.

The startup script (which is the containers default entrypoint) checks /data/mariadb, and if it's empty it initialises it by running the /usr/bin/mysql_install_db command, and then runs /usr/bin/mysqld_safe with an initial SQL file which ensures the database is securely configured for remote access. If the /data/mariadb folder contains data then it just runs /usr/bin/mysqld_safe.

The steps that are performed to secure the database were taken from howtolamp.com. In summary the script:

• Deletes anonymous users
• Deletes full access to the test database
• Deletes full access to databases beginning in test
• Deletes the test database
• Sets the root password as abc123 Note - you should change this!!
• Creates a docker user with full permissions to all databases from all hosts with the password docker Note - you should change this

Creating and running the container

To create and run the container:

docker run --privileged=true -v /data/mariadb:/data/mariadb:rw -p 3306:3306 -d --name mariadb dylanlindgren/docker-mariadb

• -p publishes the container's 3306 port to 3306 on the host
• --name sets the name of the container (useful when starting/stopping).
• -v maps the /data/mariadb folder as read/write (rw).
• -d runs the container as a daemon

To stop the container:

docker stop mariadb

To start the container again:

docker start mariadb

Running as a Systemd service

To run this container as a service on a Systemd based distro (e.g. CentOS 7), create a unit file under /etc/systemd/system called mariadb.service with the below contents

[Unit]
Description=MariaDB Docker container (dylanlindgren/docker-mariadb)
After=docker.service
Requires=docker.service

[Service]
TimeoutStartSec=0
ExecStartPre=-/usr/bin/docker stop mariadb
ExecStartPre=-/usr/bin/docker rm mariadb
ExecStartPre=-/usr/bin/docker pull dylanlindgren/docker-mariadb
ExecStart=/usr/bin/docker run --privileged=true -v /data/mariadb:/data/mariadb:rw -p 3306:3306 --name mariadb dylanlindgren/docker-mariadb
ExecStop=/usr/bin/docker stop mariadb

[Install]
WantedBy=multi-user.target

Then you can start/stop/restart the container with the regular Systemd commands e.g. systemctl start mariadb.service.

To automatically start the container when you restart enable the unit file with the command systemctl enable mariadb.service.