instruction: Create a Dockerfile for configuration
output: ```dockerfile
  from those files when
  initializing the system database for the first time. Afterward, the
  passwords are stored in the MySQL system database itself.Sets environment variables MYSQL_USER and MYSQL_DATABASE. A new
  database called wordpress is created when the container starts, and the
  wordpress user has full permissions for this database only. This
  user cannot create or drop databases or change the MySQL
  configuration.
  
  $ docker service create \
   --name mysql \
   --replicas 1 \
   --network mysql_private \
   --mount type=volume,source=mydata,destination=/var/lib/mysql \
   --secret source=mysql_root_password,target=mysql_root_password \
   --secret source=mysql_password,target=mysql_password \
   -e MYSQL_ROOT_PASSWORD_FILE="/run/secrets/mysql_root_password" \
   -e MYSQL_PASSWORD_FILE="/run/secrets/mysql_password" \
   -e MYSQL_USER="wordpress" \
   -e MYSQL_DATABASE="wordpress" \
   mysql:latest
  Verify that the mysql container is running using the docker service ls command.
  
  $ docker service ls
  
  ID NAME MODE REPLICAS IMAGE
  wvnh0siktqr3 mysql replicated 1/1 mysql:latest
  Now that MySQL is set up, create a WordPress service that connects to the
  MySQL service. The WordPress service has the following characteristics:Because the scale is set to 1, only a single WordPress task runs.
  Load-balancing WordPress is left as an exercise to the reader, because of
  limitations with storing WordPress session data on the container
  filesystem.Exposes WordPress on port 30000 of the host machine, so that you can access
  it
  ```