Build container providing MariaDB as a service
Tags for MariaDB 5.5 and 10.1 are available.
What is MariaDB?
MariaDB is a community-developed fork of the MySQL relational database management
system intended to remain free under the GNU GPL. Being a fork of a leading open
source software system, it is notable for being led by the original developers of
MySQL, who forked it due to concerns over its acquisition by Oracle. Contributors
are required to share their copyright with the MariaDB Foundation.
The intent is also to maintain high compatibility with MySQL, ensuring a "drop-in"
replacement capability with library binary equivalency and exact matching with
MySQL APIs and commands. It includes the XtraDB storage engine for replacing
InnoDB, as well as a new storage engine, Aria, that intends to be both a
transactional and non-transactional engine perhaps even included in future
versions of MySQL.
How to use this image
mariadb server instance
$ docker run --name some-mariadb -e MYSQL_ROOT_PASSWORD=my-secret-pw -d danielsreichenbach/mariadb:tag
some-mariadb is the name you want to assign to your container,
my-secret-pw is the password to be set for the MariaDB root user and
the tag specifying the MariaDB version you want. See the tag list on Docker Hub
for available tags.
Connect to MariaDB from an application in another Docker container
Since MariaDB is intended as a drop-in replacement for MariaDB, it can be used
with many applications. This image exposes the standard MySQL port (3306), so
container linking makes the MariaDB instance available to other application
containers. Start your application container like this in order to link it to
the MariaDB container:
$ docker run --name some-app --link some-mariadb:mysql -d application-that-uses-mysql
Connect to MariaDB from the MariaDB command line client
The following command starts another MariaDB container instance and runs the
mysql command line client against your original MariaDB container, allowing you
to execute SQL statements against your database instance:
$ docker run -it --link some-mariadb:mysql --rm mariadb sh -c 'exec mysql -h"$MYSQL_PORT_3306_TCP_ADDR" -P"$MYSQL_PORT_3306_TCP_PORT" -uroot -p"$MYSQL_ENV_MYSQL_ROOT_PASSWORD"'
some-mariadb is the name of your original MariaDB container.
More information about the MySQL command line client can be found in the
Container shell access and viewing logs
docker exec command allows you to run commands inside a Docker container.
The following command line will give you a sh shell inside your MariaDB
$ docker exec -it some-mariadb sh
The MariaDB Server log is available through Docker's container log:
$ docker logs some-mariadb
Using a custom MariaDB configuration file
The MariaDB startup configuration is specified in the file
and that file in turn includes any files found in the
directory that end with
.cnf. Settings in files in this directory will augment
and/or override settings in
/etc/mysql/my.cnf. If you want to use a customized
MariaDB configuration, you can create your alternative configuration file in a
directory on the host machine and then mount that directory location as
/etc/mysql/conf.d inside the MariaDB container.
/my/custom/config-file.cnf is the path and name of your custom configuration
file, you can start your MariaDB container like this (note that only the directory
path of the custom config file is used in this command):
$ docker run --name some-mariadb -v /my/custom:/etc/mysql/conf.d -e MYSQL_ROOT_PASSWORD=my-secret-pw -d mariadb:tag
This will start a new container
some-mariadb where the MariaDB instance uses
the combined startup settings from
/etc/mysql/conf.d/config-file.cnf, with settings from the latter taking
Note that users on host systems with SELinux enabled may see issues with this.
The current workaround is to assign the relevant SELinux policy type to your new
config file so that the container will be allowed to mount it:
$ chcon -Rt svirt_sandbox_file_t /my/custom
When you start the
mariadb image, you can adjust the configuration of the MariaDB
instance by passing one or more environment variables on the docker run command line.
Do note that none of the variables below will have any effect if you start the container
with a data directory that already contains a database: any pre-existing database will
always be left untouched on container startup.
This variable is mandatory and specifies the password that will be set for the
MariaDB root superuser account. In the above example, it was set to
This variable is optional and allows you to specify the name of a database to be
created on image startup. If a user/password was supplied (see below) then that
user will be granted superuser access (corresponding to
GRANT ALL) to this database.
These variables are optional, used in conjunction to create a new user and to set
that user's password. This user will be granted superuser permissions (see above)
for the database specified by the
MYSQL_DATABASE variable. Both variables are
required for a user to be created.
Do note that there is no need to use this mechanism to create the root superuser,
that user gets created by default with the password specified by the
This is an optional variable. Set to yes to allow the container to be started
with a blank password for the root user. NOTE: Setting this variable to yes is
not recommended unless you really know what you are doing, since this will leave
your MariaDB instance completely unprotected, allowing anyone to gain complete
Initializing a fresh instance
When a container is started for the first time, a new database
mysql will be
initialized with the provided configuration variables. Furthermore, it will
execute files with extensions
.sql that are found in
/docker-entrypoint-initdb.d. You can easily populate your
by mounting a SQL dump into that directory and provide
custom images with contributed data.
Caveats Where to Store Data
Important note: There are several ways to store data used by applications that
run in Docker containers. We encourage users of the
mariadb images to
familiarize themselves with the options available, including:
- Let Docker manage the storage of your database data by writing the database
files to disk on the host system using its own internal volume management.
This is the default and is easy and fairly transparent to the user. The
downside is that the files may be hard to locate for tools and applications
that run directly on the host system, i.e. outside containers.
- Create a data directory on the host system (outside the container) and mount
this to a directory visible from inside the container. This places the database
files in a known location on the host system, and makes it easy for tools and
applications on the host system to access the files. The downside is that the
user needs to make sure that the directory exists, and that e.g. directory
permissions and other security mechanisms on the host system are set up correctly.
The Docker documentation is a good starting point for understanding the different
storage options and variations, and there are multiple blogs and forum postings
that discuss and give advice in this area. We will simply show the basic procedure
here for the latter option above:
- Create a data directory on a suitable volume on your host system, e.g.
mariadbcontainer like this:
$ docker run --name some-mariadb -v /my/own/datadir:/var/lib/mysql -e MYSQL_ROOT_PASSWORD=my-secret-pw -d mariadb:tag
-v /my/own/datadir:/var/lib/mysql part of the command mounts the
directory from the underlying host system as
/var/lib/mysql inside the container,
where MariaDB by default will write its data files.
Note that users on host systems with SELinux enabled may see issues with this.
The current workaround is to assign the relevant SELinux policy type to the new
data directory so that the container will be allowed to access it:
$ chcon -Rt svirt_sandbox_file_t /my/own/datadir
No connections until MariaDB init completes
If there is no database initialized when the container starts, then a default
database will be created. While this is the expected behavior, this means that it
will not accept incoming connections until such initialization completes. This
may cause issues when using automation tools, such as
start several containers simultaneously.
Usage against an existing database
If you start your
mariadb container instance with a data directory that already
contains a database (specifically, a
mysql subdirectory), the
variable should be omitted from the run command line; it will in any case be
ignored, and the pre-existing database will not be changed in any way.
Supported Docker versions
This image is officially supported on Docker version 1.9.0.
Support for older versions (down to 1.6) is provided on a best-effort basis.
Please see the Docker installation documentation for
details on how to upgrade your Docker daemon.
The container can be used to compose services in Drone, as shown in the
services: mysql: image: danielsreichenbach/mariadb:10.1 environment: - MYSQL_DATABASE=test - MYSQL_ALLOW_EMPTY_PASSWORD=yes
This would connect a running MariaDB instance to your container, providing
password-less access, and an empty