Docker containers are lightweight and portable, making them a great tool for running applications in your homelab. A Raspberry Pi is an ideal low-cost, low-power device for hosting Docker containers. This guide will walk you through setting up Docker on a Raspberry Pi and deploying your first container.

What You’ll Need

  • A Raspberry Pi (recommended: Raspberry Pi 3, 4, or newer).
  • MicroSD card with Raspberry Pi OS Lite installed.
  • A stable internet connection.
  • Basic knowledge of Linux commands.

Step 1: Update and Prepare Your Raspberry Pi

  1. Log into your Raspberry Pi via SSH:
ssh pi@<raspberry_pi_ip_address>
  1. Update and upgrade the system packages:
sudo apt update && sudo apt upgrade -y
  1. Install prerequisite packages:
sudo apt install -y apt-transport-https ca-certificates curl software-properties-common

Step 2: Install Docker on the Raspberry Pi

  1. Download the official Docker installation script:
curl -fsSL https://get.docker.com -o get-docker.sh
  1. Run the installation script:
sudo sh get-docker.sh
  1. Add your user to the docker group (replace pi with your username if different):
sudo usermod -aG docker pi

Log out and back in to apply the changes.

  1. Verify the Docker installation:
docker --version

Step 3: Enable Docker to Start on Boot

  1. Enable the Docker service:
sudo systemctl enable docker
  1. Check that Docker is running:
sudo systemctl status docker

Step 4: Deploy Your First Docker Container

  1. Pull an official Docker image (e.g., Nginx):
docker pull nginx
  1. Run a container using the image:
docker run -d -p 8080:80 --name webserver nginx
  1. Open a web browser and navigate to http://<raspberry_pi_ip_address>:8080. You should see the default Nginx page.

Step 5: Manage Docker Containers

  1. List running containers:
docker ps
  1. Stop a container:
docker stop webserver
  1. Restart a container:
docker start webserver
  1. Remove a container:
docker rm webserver

Step 6: Use Docker Compose (Optional)

Docker Compose is a tool for managing multi-container applications.

  1. Install Docker Compose:
sudo apt install docker-compose
  1. Create a docker-compose.yml file:
    Example:
yaml
version: "3.9"
services:
  app:
    image: nginx
    ports:
      - "8080:80"
  1. Run the application:
docker-compose up -d
  1. Stop the application:
docker-compose down

FAQs

Q: Can I use Docker on older Raspberry Pi models?
A: Yes, but performance may be limited on older models like Raspberry Pi 1 or Zero due to resource constraints.

Q: Do I need a 64-bit OS to run Docker on a Raspberry Pi?
A: While Docker runs on 32-bit systems, using a 64-bit OS is recommended for better compatibility and performance.

Q: How do I update Docker?
A: Use the following commands to update Docker:

sudo apt update && sudo apt upgrade -y

Q: Can I run multiple containers at once?
A: Yes, Docker is designed for running multiple containers simultaneously. Use docker-compose to manage multi-container applications easily.

Q: What happens if my Raspberry Pi reboots?
A: Containers will not start automatically unless you specify the --restart flag when running a container:

docker run -d --restart unless-stopped <image>

Q: How do I clean up unused Docker resources?
A: Use the following command to remove unused images, containers, and volumes:

docker system prune -a

Q: Can I access containers from outside my network?
A:Yes, configure port forwarding on your router to expose the container’s ports to the internet. Be cautious and secure your setup.

Running Docker on a Raspberry Pi is a fantastic way to explore containerized applications in your homelab. From web servers to databases, the possibilities are endless. Happy containerizing!