How To Use Docker Compose: Multi-Container Applications

Managing multi-container applications manually with Docker commands can quickly become complex and error-prone. Docker Compose simplifies this process using a single configuration file to define and run multiple containers effortlessly. In this guide, you’ll learn how to use docker compose through a real-world example.

What is Docker Compose?

Docker Compose is a tool for defining and managing multi-container Docker applications. It uses a docker-compose.yml file to configure your services, networks, and volumes — allowing you to spin everything up with just one command:

docker-compose up

Example: Python App + Redis

Let’s say you have a Python app that uses Redis to store data. Instead of starting Python and Redis separately, you can manage both in one docker-compose.yml file.

Project Structure

MultiContainerApp/
├── app.py
├── requirements.txt
└── docker-compose.yml

app.py

import redis

r = redis.Redis(host='redis', port=6379)
r.set('message', 'Hello from Docker Compose!')
print(r.get('message').decode())

requirements.txt

redis

docker-compose.yml

services:
  web:
    image: python:3.11-slim
    working_dir: /app
    volumes:
      - .:/app
    command: sh -c "pip install -r requirements.txt && python app.py"
    depends_on:
      - redis

  redis:
    image: redis:7

How to Run

1. Open terminal in the project directory

2. Run

docker-compose up

You should see output like:

web_1    | Hello from Docker Compose!

Why To Use?

This is a must-have tool for modern development with microservices or multi-tier apps. Whether you’re integrating APIs, databases, or caches, Compose lets you manage everything with clarity and control.

You can read more useful articles like Multi-Stage Builds In Docker: Save Image Size And Improve Security.

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