The correct docker-compose setup for Wordpress and Nginx

Most of the docker-compose example configurations available online for Wordpress and Nginx are not the correct approach in my opinion. This is because they suggest to mount the whole /var/www/html folder as a volume.

For example binding a local html folder:

services:
  nginx:
    ...
    volumes:
      - ./html:/var/www/html
  wordpress:
    ...
    volumes:
      - ./html:/var/www/html

The big problem with this approach is that it becomes very hard to upgrade Wordpress. When wordpress’ image version is changed, the files in the volume are not overwritten, meaning that no actual upgrade was done. We’d need to delete the files in the volume (except for the wp-content folder) and then run docker-compose up again.

The only folder we actually need to mount is wp-content to be able install and update themes and plugins. It’s a good idea to disable Wordpress automatic updates, which can be done with an environment variable. We also need a way for nginx to be able to access worpress’ files again. Named volumes come to the rescue:

services:
  nginx:
    ...
    volumes:
      - www-data:/var/www/html
      - ./html:/var/www/html/wp-content
  wordpress:
    ...
    environment:
      - WORDPRESS_CONFIG_EXTRA=
          define('AUTOMATIC_UPDATER_DISABLED', true);
    volumes:
      - www-data:/var/www/html
      - ./html:/var/www/html/wp-content
volumes:
  www-data: