Docker Compose is a tool that allows you to define and manage multi-container Docker applications. It uses a YAML file to configure the services, networks, and volumes for your application, making it easier to manage complex setups. This is particularly useful on a Raspberry Pi, where you might want to run multiple lightweight services without the overhead of a full virtual machine for each one.

Prerequisites

Before we begin, ensure that you have Docker installed on your Raspberry Pi. You can follow these steps to install Docker:

curl -sSL https://get.docker.com | sh
sudo usermod -aG docker pi

Log out and log back in to apply the changes.

Installing Docker Compose

Docker Compose is not included by default with Docker. You can install it using the following commands:

sudo apt-get update
sudo apt-get install -y libffi-dev libssl-dev
sudo apt-get install -y python3 python3-pip
sudo pip3 install docker-compose

Creating a Docker Compose File

Let's create a simple Docker Compose file to run a multi-container application. For this example, we'll run a simple web application with an Nginx front-end and a Redis back-end.

1. Create a directory for your project:

mkdir myapp
cd myapp

2. Create a docker-compose.yml file:

version: '3'

services:
  web:
    image: nginx:alpine
    ports:
      - "80:80"
    volumes:
      - ./html:/usr/share/nginx/html
  redis:
    image: redis:alpine
    ports:
      - "6379:6379"

3. Create a simple HTML file to serve:

mkdir html
echo "<h1>Hello, Raspberry Pi!</h1>" > html/index.html

Running Docker Compose

To start your multi-container application, use the following command:

docker-compose up

This will pull the necessary images and start the containers as defined in your docker-compose.yml file.

Managing Docker Compose

• Stopping the application:

  docker-compose down

• Viewing logs:

  docker-compose logs

• Running in detached mode:

  docker-compose up -d

Conclusion

Docker Compose is a powerful tool that simplifies the management of multi-container applications on your Raspberry Pi. By defining your services in a single YAML file, you can easily start, stop, and manage your application stack.