Docker 容器，连接彼此的数据库，Nginx 代理和 WordPress

Question

I trying to figure out how docker network and that kind of stuff works. So here is my setup, I have 2 docker containers with WordPress and mysql. And theese two needs to be able to talk to each other thru direct database connections. And I have domain pointed to them also. So I tried to set it up with an docker nginx proxy, but when i'm trying to visit that site thru the domain i'm getting 502 bat gateway.

So my docker ngxinx proxy compose file looks like this, but with different ports:

version: "3.1"
services:
  nginx-proxy:
    image: jwilder/nginx-proxy:alpine
    ports:
      - "80:80"
      - "443:443"
    volumes:
      - ./certs:/etc/nginx/certs
      - /var/run/docker.sock:/tmp/docker.sock:ro
    restart: unless-stopped
networks:
  default:
    external:
      name: nginx-proxy

And both of my WordPress containers look like this:

version: '3.1'

services:

  wordpress:
    image: wordpress
    restart: always
    environment:
      WORDPRESS_DB_HOST: db
      WORDPRESS_DB_USER: exampleuser
      WORDPRESS_DB_PASSWORD: examplepass
      WORDPRESS_DB_NAME: exampledb
      VIRTUAL_HOST: wp1.local
      VIRTUAL_PORT: 3000
    volumes:
      - ./wp:/var/www/html
      - ./uploads.ini:/usr/local/etc/php/conf.d/uploads.ini
    expose:
      - 3000

  db:
    image: mysql:5.7
    restart: always
    environment:
      MYSQL_DATABASE: exampledb
      MYSQL_USER: exampleuser
      MYSQL_PASSWORD: examplepass
      MYSQL_RANDOM_ROOT_PASSWORD: '1'
    volumes:
      - db:/var/lib/mysql
    ports:
      - "8086:3306"

  mailhog:
    image: mailhog/mailhog
    ports:
      - "1025:1025" # smtp server
      - "8025:8025" # web ui

networks:
  default:
    external:
      name: nginx-proxy

volumes:
  db:

And I have added 127.0.0.1 wp1 to /etc/hosts

But when I start the proxy and one of the WP containers I'm getting bad gateway. And I have no clue how to move forward. And maybe this is not even the right way todo it. Becuase the problem i'm trying to solve is that wp2 needs to be able to connect to wp1 database thru custom pdo connection.

I tried to explain as good as I can, but this is a new area for me when it comes to docker networks. Also i'm running docker for windows with wsl2

Answer 1

You should add

networks: 
 - default

to each service definition in docker-compose.

version: '3.1'    

services:

  wordpress:
    image: wordpress
    restart: always
    environment:
      WORDPRESS_DB_HOST: db
      WORDPRESS_DB_USER: exampleuser
      WORDPRESS_DB_PASSWORD: examplepass
      WORDPRESS_DB_NAME: exampledb
      VIRTUAL_HOST: wp1.local
      VIRTUAL_PORT: 3000
    volumes:
      - ./wp:/var/www/html
      - ./uploads.ini:/usr/local/etc/php/conf.d/uploads.ini
    expose:
      - 3000
    networks:
      - default

  db:
    image: mysql:5.7
    restart: always
    environment:
      MYSQL_DATABASE: exampledb
      MYSQL_USER: exampleuser
      MYSQL_PASSWORD: examplepass
      MYSQL_RANDOM_ROOT_PASSWORD: '1'
    volumes:
      - db:/var/lib/mysql
    ports:
      - "8086:3306"
    networks:
      -default

  mailhog:
    image: mailhog/mailhog
    ports:
      - "1025:1025" # smtp server
      - "8025:8025" # web ui
    networks:
      - default

networks:
  default:
    external:
      name: nginx-proxy

volumes:
  db: