mariadb
Estimated reading time: 12 minutesMariaDB is a community-developed fork of MySQL intended to remain free under the GNU GPL.
GitHub repo: https://github.com/docker-library/mariadb
Library reference
This content is imported from the official Docker Library docs, and is provided by the original uploader. You can view the Docker Hub page for this image at https://hub.docker.com/images/mariadb
Supported tags and respective Dockerfile
links
10.4.4-bionic
,10.4-bionic
,rc-bionic
,10.4.4
,10.4
,rc
(10.4/Dockerfile)10.3.14-bionic
,10.3-bionic
,10-bionic
,bionic
,10.3.14
,10.3
,10
,latest
(10.3/Dockerfile)10.2.23-bionic
,10.2-bionic
,10.2.23
,10.2
(10.2/Dockerfile)10.1.38-bionic
,10.1-bionic
,10.1.38
,10.1
(10.1/Dockerfile)10.0.38-xenial
,10.0-xenial
,10.0.38
,10.0
(10.0/Dockerfile)5.5.63-trusty
,5.5-trusty
,5-trusty
,5.5.63
,5.5
,5
(5.5/Dockerfile)
Quick reference
-
Where to get help:
the Docker Community Forums, the Docker Community Slack, or Stack Overflow -
Where to file issues:
https://github.com/docker-library/mariadb/issues -
Maintained by:
the Docker Community -
Supported architectures: (more info)
amd64
,arm64v8
,i386
,ppc64le
-
Published image artifact details:
repo-info repo’srepos/mariadb/
directory (history)
(image metadata, transfer size, etc) -
Image updates:
official-images PRs with labellibrary/mariadb
official-images repo’slibrary/mariadb
file (history) -
Source of this description:
docs repo’smariadb/
directory (history) -
Supported Docker versions:
the latest release (down to 1.6 on a best-effort basis)
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
Start a mariadb
server instance
Starting a MariaDB instance is simple:
$ docker run --name some-mariadb -e MYSQL_ROOT_PASSWORD=my-secret-pw -d mariadb:tag
... where some-mariadb
is the name you want to assign to your container, my-secret-pw
is the password to be set for the MySQL root user and tag
is the tag specifying the MySQL version you want. See the list above for relevant tags.
Connect to MariaDB from the MySQL 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 --network some-network --rm mariadb mysql -hsome-mariadb -uexample-user -p
... where some-mariadb
is the name of your original mariadb
container (connected to the some-network
Docker network).
This image can also be used as a client for non-Docker or remote instances:
$ docker run -it --rm mariadb mysql -hsome.mysql.host -usome-mysql-user -p
More information about the MySQL command line client can be found in the MySQL documentation
... via docker stack deploy
or docker-compose
Example stack.yml
for mariadb
:
# Use root/example as user/password credentials
version: '3.1'
services:
db:
image: mariadb
restart: always
environment:
MYSQL_ROOT_PASSWORD: example
adminer:
image: adminer
restart: always
ports:
- 8080:8080
Run docker stack deploy -c stack.yml mariadb
(or docker-compose -f stack.yml up
), wait for it to initialize completely, and visit http://swarm-ip:8080
, http://localhost:8080
, or http://host-ip:8080
(as appropriate).
Container shell access and viewing MySQL logs
The docker exec
command allows you to run commands inside a Docker container. The following command line will give you a bash shell inside your mariadb
container:
$ docker exec -it some-mariadb bash
The log is available through Docker’s container log:
$ docker logs some-mariadb
Using a custom MySQL configuration file
The startup configuration is specified in the file /etc/mysql/my.cnf
, and that file in turn includes any files found in the /etc/mysql/conf.d
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 MySQL 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.
If /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/my.cnf
and /etc/mysql/conf.d/config-file.cnf
, with settings from the latter taking precedence.
Configuration without a cnf
file
Many configuration options can be passed as flags to mysqld
. This will give you the flexibility to customize the container without needing a cnf
file. For example, if you want to change the default encoding and collation for all tables to use UTF-8 (utf8mb4
) just run the following:
$ docker run --name some-mariadb -e MYSQL_ROOT_PASSWORD=my-secret-pw -d mariadb:tag --character-set-server=utf8mb4 --collation-server=utf8mb4_unicode_ci
If you would like to see a complete list of available options, just run:
$ docker run -it --rm mariadb:tag --verbose --help
Environment Variables
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.
MYSQL_ROOT_PASSWORD
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 my-secret-pw
.
MYSQL_DATABASE
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.
MYSQL_USER
, MYSQL_PASSWORD
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 MYSQL_ROOT_PASSWORD
variable.
MYSQL_ALLOW_EMPTY_PASSWORD
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 superuser access.
MYSQL_RANDOM_ROOT_PASSWORD
This is an optional variable. Set to yes
to generate a random initial password for the root user (using pwgen
). The generated root password will be printed to stdout (GENERATED ROOT PASSWORD: .....
).
Docker Secrets
As an alternative to passing sensitive information via environment variables, _FILE
may be appended to the previously listed environment variables, causing the initialization script to load the values for those variables from files present in the container. In particular, this can be used to load passwords from Docker secrets stored in /run/secrets/<secret_name>
files. For example:
$ docker run --name some-mysql -e MYSQL_ROOT_PASSWORD_FILE=/run/secrets/mysql-root -d mariadb:tag
Currently, this is only supported for MYSQL_ROOT_PASSWORD
, MYSQL_ROOT_HOST
, MYSQL_DATABASE
, MYSQL_USER
, and MYSQL_PASSWORD
.
Initializing a fresh instance
When a container is started for the first time, a new database with the specified name will be created and initialized with the provided configuration variables. Furthermore, it will execute files with extensions .sh
, .sql
and .sql.gz
that are found in /docker-entrypoint-initdb.d
. Files will be executed in alphabetical order. You can easily populate your mariadb
services by mounting a SQL dump into that directory and provide custom images with contributed data. SQL files will be imported by default to the database specified by the MYSQL_DATABASE
variable.
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.
/my/own/datadir
. -
Start your
mariadb
container like this:$ docker run --name some-mariadb -v /my/own/datadir:/var/lib/mysql -e MYSQL_ROOT_PASSWORD=my-secret-pw -d mariadb:tag
The -v /my/own/datadir:/var/lib/mysql
part of the command mounts the /my/own/datadir
directory from the underlying host system as /var/lib/mysql
inside the container, where MySQL by default will write its data files.
No connections until MySQL 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 docker-compose
, which 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 $MYSQL_ROOT_PASSWORD
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.
Creating database dumps
Most of the normal tools will work, although their usage might be a little convoluted in some cases to ensure they have access to the mysqld
server. A simple way to ensure this is to use docker exec
and run the tool from the same container, similar to the following:
$ docker exec some-mariadb sh -c 'exec mysqldump --all-databases -uroot -p"$MYSQL_ROOT_PASSWORD"' > /some/path/on/your/host/all-databases.sql
License
View license information for the software contained in this image.
As with all Docker images, these likely also contain other software which may be under other licenses (such as Bash, etc from the base distribution, along with any direct or indirect dependencies of the primary software being contained).
Some additional license information which was able to be auto-detected might be found in the repo-info
repository’s mariadb/
directory.
As for any pre-built image usage, it is the image user’s responsibility to ensure that any use of this image complies with any relevant licenses for all software contained within.