如何在两个容器之间正确共享相同的主机卷？

Question

Since volumes_from disappear when Docker Compose change it's compose file version I am a bit lost in how to share a volume between different containers.

See the example below where a PHP application is living in a PHP-FPM container and Nginx is living in a second one.

version: '3.3'

services:
    php:
        build:
            context: ./docker/php7-fpm
            args:
                TIMEZONE: ${TIMEZONE}
        env_file: .env
        volumes:
          - shared-volume:/var/www
    nginx:
        build: ./docker/nginx
        ports:
            - 81:80
        depends_on:
            - php
        volumes:
          - shared-volume:/var/www
volumes:
  shared-volume:
    driver_opts:
      type: none
      device: ~/sources/websocket
      o: bind

In order to make the application works of course somehow Nginx has to access the PHP files and there is where volumes_from help us a lot. Now that option is gone.

When I try the command docker-compose up it ends with the following message:

ERROR: for websocket_php_1 Cannot create container for service php: error while mounting volume with options: type='none' device='~/sources/websocket' o='bind': no such file or directory

How do I properly share the same host volume between the two containers?

Answer 1

Why would you not use a bind mount? This is just source code that each needs to see, correct? I added the :ro (read-only) option which assumes no code generation is happening.

services:
    php:
        build:
            context: ./docker/php7-fpm
            args:
                TIMEZONE: ${TIMEZONE}
        env_file: .env
        volumes:
            # User-relative path
            - ~/sources/websocket:/var/www:ro

    nginx:
        build: ./docker/nginx
        ports:
            - 81:80
        depends_on:
            - php
         volumes:
            # User-relative path
            - ~/sources/websocket:/var/www:ro