This entry doesn't reveal any hidden secrets just the simple steps to start using MySQL on Docker.
* Install docker

* Install docker-compose

* mkdir firstdb

* cd firstdb

* vi docker-compose.yml

mysql:
image: mysql:latest
environment:
MYSQL_DATABASE: sample
MYSQL_USER: mysql
MYSQL_PASSWORD: mysql
MYSQL_ROOT_PASSWORD: supersecret

* docker-compose up
* docker-compose ps

Name Command State Ports
-----------------------------------------------------------------
firstdb_mysql_1 /entrypoint.sh mysqld Up 3306/tcp

* Use a one-shot Docker instance to display environment variables. Notice
the variables that start with MYSQL? Your programs can use these variables
to make the database connection.

docker run --link=firstdb_mysql_1:mysql ubuntu env
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
HOSTNAME=abfc8d50633b
MYSQL_PORT=tcp://172.17.0.23:3306
MYSQL_PORT_3306_TCP=tcp://172.17.0.23:3306
MYSQL_PORT_3306_TCP_ADDR=172.17.0.23
MYSQL_PORT_3306_TCP_PORT=3306
MYSQL_PORT_3306_TCP_PROTO=tcp
MYSQL_NAME=/nostalgic_rosalind/mysqldb
MYSQL_ENV_MYSQL_PASSWORD=mysql
MYSQL_ENV_MYSQL_ROOT_PASSWORD=supersecret
MYSQL_ENV_MYSQL_USER=mysql
MYSQL_ENV_MYSQL_DATABASE=sample
MYSQL_ENV_MYSQL_MAJOR=5.6
MYSQL_ENV_MYSQL_VERSION=5.6.24
HOME=/root

* Use a one-shot Docker instance for a MySQL command-line interface. Once this
is running, you'll be able to use command like 'show databases'.

docker run -it \
--link=firstcompose_mysqldb_1:mysql \
--rm \
mysql/mysql-server:latest \
sh -c 'exec mysql -h"$MYSQL_PORT_3306_TCP_ADDR" -P"$MYSQL_PORT_3306_TCP_PORT" -uroot -p"$MYSQL_ENV_MYSQL_ROOT_PASSWORD"'

That's all it takes to start.