https://hub.docker.com/_/mariadb?tab=description

 

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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-networkDocker 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 

... via  or 

Example stack.yml for mariadb:

# Use root/example as user/password credentialsversion: '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 () 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  and provide  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 . 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 . 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:

1. Create a data directory on a suitable volume on your host system, e.g. /my/own/datadir.

2. 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  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 .

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.

 

===============

 

Creating a Container

An image is not a running process; it is just the software needed to be launched. To run it, we must create a container first. The command needed to create a container can usually be found in the image documentation. For example, to create a container for the official MariaDB image:

docker run --name mariadbtest -e MYSQL_ROOT_PASSWORD=mypass -d mariadb/server:10.3

mariadbtest is the name we want to assign the container. If we don't specify a name, an id will be automatically generated.

10.1 and 10.2 are also valid target versions:

docker run --name mariadbtest -e MYSQL_ROOT_PASSWORD=mypass -d mariadb/server:10.1

docker run --name mariadbtest -e MYSQL_ROOT_PASSWORD=mypass -d mariadb/server:10.2

Optionally, after the image name, we can specify some . For example:

docker run --name mariadbtest -e MYSQL_ROOT_PASSWORD=mypass -d mariadb/server:10.3 --log-bin --binlog-format=MIXED

Docker will respond with the container's id. But, just to be sure that the container has been created and is running, we can get a list of running containers in this way:

docker ps

We should get an output similar to this one:

CONTAINER ID        IMAGE                      COMMAND                CREATED             STATUS              PORTS               NAMES819b786a8b48        mariadb/server             "/docker-entrypoint.   4 minutes ago       Up 4 minutes        3306/tcp            mariadbtest

Running and Stopping the Container

Docker allows us to restart a container with a single command:

docker restart mariadbtest

The container can also be stopped like this:

docker stop mariadbtest

The container will not be destroyed by this command. The data will still live inside the container, even if MariaDB is not running. To restart the container and see our data, we can issue:

docker start mariadbtest

With docker stop, the container will be gracefully terminated: a SIGTERM signal will be sent to the mysqld process, and Docker will wait for the process to shutdown before returning the control to the shell. However, it is also possible to set a timeout, after which the process will be immediately killed with a SIGKILL. Or it is possible to immediately kill the process, with no timeout.

docker stop --time=30 mariadbtestdocker kill mariadbtest

In case we want to destroy a container, perhaps because the image does not suit our needs, we can stop it and then run:

docker rm mariadbtest

Note that the command above does not destroy the data volume that Docker has created for /var/lib/mysql. If you want to destroy the volume as well, use:

docker rm -v mariadbtest

Pausing Containers

A container can also be frozen with the pause command. Docker will freeze the process using croups. MariaDB will not know that it is being frozen and, when we unpause it, MariaDB will resume its work as expected.

Both pause and unpause accept one or more container names. So, if we are running a cluster, we can freeze and resume all nodes simultaneously:

docker pause node1 node2 node3docker unpause node1 node2 node3

Pausing a container is very useful when we need to temporarily free our system's resources. If the container is not crucial at this moment (for example, it is performing some batch work), we can free it to allow other programs to run faster.

Troubleshooting a Container

If the container doesn't start, or is not working properly, we can investigate with the following command:

docker logs mariadbtest

This command shows what the daemon sent to the stdout since the last attempt of starting - the text that we typically see when we invoke mysqld from the command line.

On some systems, including recent Ubuntu releases, commands such as docker stop mariadbtest and docker restart mariadbtest may fail with a permissions error. This can be caused by the AppArmor package, and even sudowon't allow you to execute the command. You can totally remove AppArmor using the following commands:

sudo apt-get purge --auto-remove apparmorsudo service docker restartdocker system prune --all --volumes

Restarting the system will then allow Docker to operate normally. More information is available in the Docker forums: 

Accessing the Container

To access the container via Bash, we can run this command:

docker exec -it mariadbtest bash

Now we can use normal Linux commands like cd, ls, etc. We will have root privileges. We can even install our favorite file editor, for example:

apt-get updateapt-get install vim

In some images, no repository is configured by default, so we may need to add them.

Note that if we run  or the  command to stop the container, the container will be deactivated, and we will automatically exit to our system.

Connecting to MariaDB from Outside the Container

If we try to connect to the MariaDB server on localhost, the client will bypass networking and attempt to connect to the server using a socket file in the local filesystem. However, this doesn't work when MariaDB is running inside a container because the server's filesystem is isolated from the host. The client can't access the socket file which is inside the container, so it fails to connect.

Therefore connections to the MariaDB server must be made using TCP, even when the client is running on the same machine as the server container.

Most MariaDB images, including the official one, have external TCP connections disabled using the bind-address option in their #my.cnf# file. The docker image used in this guide is based on Ubuntu, so the file is located at /etc/mysql/my.cnf.

To use MariaDB we will need to edit the configuration file to change the appropriate option, and then restart the container.

Inside the container, edit the file my.cnf and check for the line that begins bind-address. Put a hash at the start of the line to comment it out:

#bind-address            = 127.0.0.1

Save the file.

While still inside the container, send the shutdown command to MariaDB. This will shut down the server and also exit back out to the host:

mysqladmin -u root -p shutdown

Start the container again. This time the MariaDB server will have networking enabled:

docker start mariadbtest

Find the IP address that has been assigned to the container:

docker inspect -f '{
  {range .NetworkSettings.Networks}}{
  {.IPAddress}}{
  {end}}' mariadbtest

You can now connect to the MariaDB server using a TCP connection to that IP address.

Forcing a TCP Connection

After enabling network connections in MariaDB as described above, we will be able to connect to the server from outside the container.

On the host, run the client and set the server address ("-h") to the container's IP address that you found in the previous step:

mysql -h 172.17.0.2 -u root -p

This simple form of the connection should work in most situations. Depending on your configuration, it may also be necessary to specify the port for the server or to force TCP mode:

mysql -h 172.17.0.2 -P 3306 --protocol=TCP -u root -p

Port Configuration for Clustered Containers and Replication

Multiple MariaDB servers running in separate Docker containers can connect to each other using TCP. This is useful for forming a Galera cluster or for replication.

When running a cluster or a replication setup via Docker, we will want the containers to use different ports. The fastest way to achieve this is mapping the containers ports to different port on our system. We can do this when creating the containers (docker run command), by using the -p option, several times if necessary. For example, for Galera nodes we will use a mapping similar to this one:

-p 4306:3306 -p 5567:5567 -p 5444:5444 -p 5568:5568

Installing MariaDB on Another Image

It is possible to download a Linux distribution image, and to install MariaDB on it. This is not much harder than installing MariaDB on a regular operating system (which is easy), but it is still the hardest option. Normally we will try existing images first. However, it is possible that no image is available for the exact version we want, or we want a custom installation, or perhaps we want to use a distribution for which no images are available. In these cases, we will install MariaDB in an operating system image.

Daemonizing the Operating System

First, we need the system image to run as a daemon. If we skip this step, MariaDB and all databases will be lost when the container stops.

To demonize an image, we need to give it a command that never ends. In the following example, we will create a Debian Jessie daemon that constantly pings the 8.8.8.8 special address:

docker run --name debian -p 3306:3306 -d debian /bin/sh -c "while true; do ping 8.8.8.8; done"

Installing MariaDB

At this point, we can enter the shell and issue commands. First we will need to update the repositories, or no packages will be available. We can also update the packages, in case some of them are newer than the image. Then, we will need to install a text editor; we will need it to edit configuration files. For example:

docker exec -ti debian bashapt-get -y updateapt-get -y upgradeapt-get -y install vim

Now we are ready to  in the way we prefer.