multiple docker compose container - single ip

Question

I have this application.

version: "2"
services:
  web:
   image: kartoffeltoby/typo3:latest
   hostname: localhost
   container_name: web
   ports:
    - 80:80
   link:
    - db:database
   volumes:
    - ./www/:/var/www/
   environment:
    - DOCROOT=/var/www/web
    - PAGESPEED=Off


  db:
   image: mysql:5.6
   hostname: database
   volumes:
    - ./DB/:/var/lib/mysql/
    - ./db/:/var/tmp/db
   environment:
    - MYSQL_ROOT_PASSWORD=passwort

Answer 1

The solution is:

network_mode: service:web

version: "2"
  services:
    typo3:
     image: kartoffeltoby/typo3:latest
     hostname: axdbw.vagrant
     container_name: typo3
     volumes:
      - ./www/:/var/www/
     environment:
      - DOCROOT=/var/www/web
      - PAGESPEED=Off
     networks:
      mynet:
        ipv4_address: 172.16.47.14

    db:
     image: mysql:5.6
     volumes:
      - ./DB/:/var/lib/mysql/
      - ./db/:/var/tmp/db
     environment:
      - MYSQL_ROOT_PASSWORD=passwort
     network_mode: service:web


  networks:
    mynet:
      driver: bridge
      ipam:
        driver: default
        config:
        - subnet: 172.16.47.0/24

Answer 2

There is no reason to use a specific IP. The solution can be as simple as this:

version: "3"
  services:
    typo3:
     image: kartoffeltoby/typo3:latest
     container_name: typo3
     networks:
      - mynet

    db:
     image: mysql:5.6
     network_mode: "service:typo3"
  networks:
    mynet:
      driver: bridge

This will place the db container onto the same IP as the typo3 container. Beware of possible port collisions.

In my use-case, I had to avoid nasty cross origin errors. Hosting the database on the same IP as my frontend container helped get around those issues.