Setting Up a LAMP Stack with Docker Compose

Docker Compose is a tool that allows to declare which Docker containers should run, and which relationships should exist between them. It follows the infrastructure as code approach, just like most automation software and Docker itself.

The docker-compose.yml File

When using Docker Compose, the Docker infrastructure must be described in a YAML file called docker-compose.yml.

Let's see an example:

version: "3"

services:
  web:
    image: "apache:${PHP_VERSION}"
    restart: 'always'
    depends_on:
      - mariadb
    restart: 'always'
    ports:
      - '8080:80'
    links:
      - mariadb
  mariadb:
    image: "mariadb-${MARIADB_VERSION}"
    restart: 'always'
    volumes: 
      - ${MARIADB_DATA_DIR-./data/mysql}:/var/lib/mysql
    environment:
      MYSQL_ROOT_PASSWORD: ${MYSQL_ROOT_PASSWORD}
      MYSQL_DATABASE: ${MYSQL_DATABASE}
      MYSQL_USER: ${MYSQL_USER}
      MYSQL_PASSWORD: ${MYSQL_PASSWORD}

In the first line we declare that we are using the version 3 of the Docker compose language.

Then we have the list of services, namely the web and the mariadb services.

For web, we map the 8080 container port to the 80 host system port. This is very useful for a development environment, because it allows us to connect our browser to the containerized web server. Also in the links property we declare that this container must be able to connect mariadb. We also have a depends_on property to declare that mariadb needs to start before web. This is because we cannot do anything with our application until MariaDB is ready to accept connections. restart: always declares that the container must restart if it crashes.

Docker Compose Commands

Docker Compose Resources

• Overview of Docker Compose in the Docker documentation
• Compose file in the Docker documentation
• Docker Compose on GitHub

Content initially contributed by Vettabase Ltd.