Lab 9
Add a Database

Goals

Use Docker Compose to add a database to our project.

Create docker-compose.yml

Running PHP on an Apache server is great, but most web applications also need a database. Often, this database runs on a system separate from the web server. Docker Compose is a tool that makes it easy to configure several Docker containers at once and create a network between them. For this project, we’re going to use a Docker image that runs MySQL.

All configuration for Docker Compose is driven by a file called docker-compose.yml. Compose looks for this file in the current directory. Let’s add it to our website project (as a file in the my-docker-website directory).

docker-compose.yml

version: '3'

services:

  web:
    image: php:7.1-apache
    depends_on:
      - db
    volumes:
      - ./:/var/www/html
    ports:
      - "80:80"

  db:
    image: mysql:5.6
    environment:
      - MYSQL_ROOT_PASSWORD=password
      - MYSQL_DATABASE=SCHOOL
      - MYSQL_USER=my_user
      - MYSQL_PASSWORD=password
    volumes:
      - ./docker-entrypoint-initdb.d:/docker-entrypoint-initdb.d
    ports:
      - "3306:3306"

Let’s break that down. If you’re curious, you can also follow along in the docker-compose.yml docs.

• We’re using version 3 of the docker-compose.yml file format.
• We have 2 “services” or “containers”. One for the web server, and one for the database.
• You’ll recognize most of the configuration options for our web server. They’re the same ones we passed on the command line in a previous lab.
• We’re setting several environment variables to configure our database. These are documented on the MySQL Docker Hub page.
• We’re mounting ./docker-entrypoint-initdb.d from our host into /docker-entrypoint-initdb.d in our MySQL container. This is also documented on the MySQL Docker Hub page.
• We’re forwarding port 3306 so we can connect to the database on localhost.

We’re going to want some data in our database. Download this SCHOOL.sql file to my-docker-website/docker-entrypoint-initdb.d/SCHOOL.sql so that it can be used to initialize our database.

At this point, you could run docker-compose up, but nothing interesting would happen because our web server doesn’t interact with our database yet. In the next lab, we’ll add some new functionality to our web server.