Docker-compose multi-container example with default network

Remarks#

By default Compose sets up a single network for your app. Each container for a service joins the default network and is both reachable by other containers on that network, and discoverable by them at a hostname identical to the container name.

Links allow you to define extra aliases by which a service is reachable from another service. They are not required to enable services to communicate – by default, any service can reach any other service at that service’s name.

https://docs.docker.com/compose/networking/

How to create a basic LAMP environment with default networking

docker-compose.yml

version: '2'
services:
  php:
     image: phpmyadmin/phpmyadmin
     links:
       - mysql:db
     depends_on:
       - mysql

  mysql:
    image: k0st/alpine-mariadb
    volumes:
      - ./data/mysql:/var/lib/mysql
    environment:
      - MYSQL_DATABASE=mydb
      - MYSQL_USER=myuser
      - MYSQL_PASSWORD=mypass 

  nginx:
    image: nginx:stable-alpine
    ports:
      - "81:80"
    volumes:
      - ./nginx/log:/var/log/nginx
      - ./nginx/nginx.conf:/etc/nginx/nginx.conf:ro
    depends_on:
      - php

nginx/nginx.conf

worker_processes  1;
events {
  worker_connections  1024;
}
http {
  sendfile  off;
  server {
    listen 80;
 
    location / {
      proxy_pass  https://php;
      proxy_set_header Host $host;
      proxy_redirect     off;
    }
  }
}

Note the nginx config is simplified but above should work for testing — basically all it’s doing is proxying the php app. Maps to port 81 to avoid conflicts on the host - adjust as needed.

Regarding linking, you can see that if you run: docker-compose exec mysql ping -c2 nginx to ping from the mysql container to the nginx container, you will succeed even though there are no links specified between these containers. Docker Compose will maintain those links in the default network for you.