This is our Dockerized version of MariaDB. It is essentially the same as the offical MariaDB image, except we use Phusion BaseImage as our starting point.
Ubuntu, plus modifications for Docker-friendliness, and solves the PID 1 zombie reaping problem.
Baseimage-docker only contains essential components. Learn more about the rationale.
- Ubuntu 14.04 LTS as base system.
- A correct init process ([learn more](http://blog.phusion.nl/2015/01/20/docker-and-the-pid-1-zombie-reaping-problem/)).
- Fixes APT incompatibilities with Docker.
- syslog-ng.
- The cron daemon.
- An optional SSH server (disabled by default), for those use cases where docker exec is inappropriate.
- Password and challenge-response authentication are disabled by default. Only key authentication is allowed.
- It allows an predefined key by default to make debugging easy. You should replace this ASAP. See instructions.
- [Runit](http://smarden.org/runit/) for service supervision and management.
MariaDB is a community-developed fork of MySQL 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.
Starting a MariaDB instance is simple:
$ docker run --name some-mariadb -e MYSQL_ROOT_PASSWORD=my-secret-pw -d sorentech/rite2: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.
Since MariaDB is intended as a drop-in replacement for MySQL, it can be used with many applications. This image exposes the standard MySQL port (3306), so container linking makes the MySQL instance available to other application containers. Start your application container like this in order to link it to the MySQL container:
$ docker run --name some-app --link some-mariadb:mysql -d application-that-uses-mysql
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"'
... where some-mariadb
is the name of your original mariadb container.
More information about the MySQL command line client can be found in the MySQL documentation
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 MariaDB Server log is available through Docker's container log:
$ docker logs some-mariadb
The MariaDB 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 sorentech/rite2: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.
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 my-secret-pw
.
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 MYSQL_ROOT_PASSWORD
variable.
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.
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 .sh
and .sql
that are found in /docker-entrypoint-initdb.d
. You can easily populate your mariadb services by mounting a SQL dump into that directory and provide custom images with contributed 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:
```console
$ docker run --name some-mariadb -v /my/own/datadir:/var/lib/mysql -e MYSQL_ROOT_PASSWORD=my-secret-pw -d sorentech/rite2: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.
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:
```console
$ chcon -Rt svirt_sandbox_file_t /my/own/datadir
```
## 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.
# User Feedback
## Documentation
Documentation for the official mariadb image is stored in the [`mariadb/` directory](https://github.com/docker-library/docs/tree/master/mariadb) of the [`docker-library/docs` GitHub repo](https://github.com/docker-library/docs).
## Issues
If you have any problems with or questions about this image, please contact us through a [GitHub issue](https://github.com/SorenTech/rite2/issues).