Defining services in Docker - Mini Project: Build & Apply

Defining Services with Docker Compose

📖 Scenario: You are setting up a simple web application using Docker. You want to define the services your app needs in a docker-compose.yml file.This will help you start all parts of your app with one command.

🎯 Goal: Create a docker-compose.yml file that defines two services: a web server and a database.The web server will use the nginx:latest image, and the database will use the mysql:5.7 image.

📋 What You'll Learn

Create a docker-compose.yml file

Define a service called web using the nginx:latest image

Define a service called db using the mysql:5.7 image

Add environment variables for the db service: MYSQL_ROOT_PASSWORD set to example

Print the final docker-compose.yml content

💡 Why This Matters

🌍 Real World

Docker Compose is used to run multi-container Docker applications easily by defining all services in one file.

💼 Career

Knowing how to define services in Docker Compose is essential for DevOps roles to manage application environments efficiently.

1

Create the base structure of docker-compose.yml

Create a docker-compose.yml file with the version set to "3.8" and an empty services section.

Docker

version: "3.8"
services:
  # Your code here

Need a hint?

Start by writing version: "3.8" at the top, then add services: below it.

2

Define the web service using the nginx:latest image

Add a service called web under services that uses the image nginx:latest.

Docker

version: "3.8"
services:
  web:
    # Your code here

Need a hint?

Indent the web service under services, then add image: nginx:latest under web.

3

Define the db service using the mysql:5.7 image with environment variables

Add a service called db under services that uses the image mysql:5.7 and has an environment variable MYSQL_ROOT_PASSWORD set to example.

Docker

version: "3.8"
services:
  web:
    image: nginx:latest
  db:
    # Your code here

Need a hint?

Indent the db service under services. Add image: mysql:5.7 and then add an environment section with MYSQL_ROOT_PASSWORD: example.

4

Print the complete docker-compose.yml content

Print the entire content of the docker-compose.yml file exactly as defined in previous steps.

Docker

# Your code here to print the docker-compose.yml content

Need a hint?

Use a multi-line string variable to hold the content and print it exactly.