Docker Exercise: docker-compose

The following create drupal service with persistent named datas: (docker-compose.yml)

version: "2"

services:
  drupal:
    image: drupal
    ports:
      - "8080:80"
    volumes:
      - drupal-modules:/var/www/html/modules
      - drupal-profiles:/var/www/html/profiles
      - drupal-sites:/var/www/html/sites
      - drupal-themes:/var/www/html/themes
  postgres:
    image: postgres
    environment:
      - POSTGRES_PASSWORD=1234

volumes:
  drupal-modules:
  drupal-profiles:
  drupal-sites:
  drupal-themes:

The options can be found in the official docker page from hub.docker.com. cd into the directory that contains the above docker-compose.yml and run docker-compose up.

When we are done, we use docker-compose down -v to remove everything.

Note that the service name is implicitly also the hostname of the service. For instance, when we try to connect to postgres database inside the network from one of the container (for example, our drupal service), the hostname is can be put as postgres.

Another example of docker-compose:

version: "2"

services:
  proxy:
    build:
      context: .
      dockerfile: nginx.Dockerfile
    image: nginx-custom
    ports:
      - "80:80"
  web:
    image: httpd
    volumes:
      - ./html:/usr/local/apache2/htdocs/

If image is not found, it will run the build command and tag it with the image name. There are at least two ways to customize what to build.

1. use COPY in Dockerfile
2. use volumes in docker-compose.yml.