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Define Docker Volumes in Docker Compose

The mysql image README on dockerhub describes how to persist database content in a docker volume.

For this purpose, we will create a docker volume to store the contents of the container directory /var/lib/mysql.

First, we will define our volume globally in the docker-compose file

volumes:
  db-volume:

Next, we will mount that volume into the the my-db container

  mydb:
    volumes:
    - db-volume:/var/lib/mysql

See the following file

• examples/session2/servers-with-volume.yml

Start the service

Start the server components

docker-compose \
  -f examples/session2/servers-with-volume.yml \
  up -d

Note that a volume is created in addition to the network and the containers

Creating network "session2_mynet" with the default driver
Creating volume "session2_db-volume" with default driver
Creating mydb ... done
Creating rubyserver ... done

Verify that the server initialization is complete

docker-compose \
  -f examples/session2/servers-with-volume.yml \
  logs -f

View the contents of the database from the webserver. Note that the list is empty.

• http://localhost:4567/listing

Now run the loader to load the simpsons.csv

docker-compose \
  -f examples/session2/servers-with-volume.yml \
  -f examples/session2/loader.yml \
  run data-load simpsons.csv

View the contents of the database from the webserver. Note that 5 users exist.

• http://localhost:4567/listing

Bring down the stack

docker-compose \
  -f examples/session2/servers-with-volume.yml \
  down

Note that the containers and the network are deleted.

Stopping rubyserver ... done
Stopping mydb       ... done
Removing rubyserver ... done
Removing mydb       ... done
Removing network session2_mynet

Note that the volume still exists

docker volume ls | grep 'db-volume'

Note that the volume name is prefixed with “session2”. That prefix is known as the project name. By default, the name of the folder containing the docker-compose file is used as a project name.

local     session2_db-volume

Recreate the stack

docker-compose \
  -f examples/session2/servers-with-volume.yml \
  up -d

View the contents of the database from the webserver. Note that 5 users exist.

• http://localhost:4567/listing

Clean up resources

Stop the stack

docker-compose \
  -f examples/session2/servers-with-volume.yml \
  down

Delete the volume as well

docker volume rm session2_db-volume

In the next section, we will experiment with different project settings using this docker-compose file.

project.configurations