Installing Docker on the Raspberry Pi?

The Raspberry Pi is a versatile single board computer that enables users to learn, build, and create innovative projects. Installing Docker on the Raspberry Pi allows you to take advantage of containerization technology to simplify deploying and managing applications. This guide will walk through the process of installing Docker on Raspberry Pi OS in a secure way, optimizing the software for performance, and utilizing containers to run services efficiently.

Installing Docker on the Raspberry Pi?

Preparing the Raspberry Pi

Before installing Docker, it is important to prepare the Raspberry Pi. This involves updating the system packages, enabling key capabilities, expanding the file system, and assigning static IP addresses.

Updating Packages

Run system updates to ensure the latest security patches and software versions are installed:

sudo apt update

sudo apt full-upgrade

This hardens the system and lays a solid foundation for adding Docker.

Enabling Additional Capabilities

The Raspberry Pi needs some extra configurations to support containers:

sudo raspi-config

  • Enable the Legacy Camera option
  • Enable the I2C interface
  • Enable the SPI interface
  • Expand the file system under Advanced Options
  • Reboot the system

These settings grant container access to connected peripherals.

Assigning a Static IP

For simplicity, assign the Raspberry Pi a static IP address. Edit /etc/dhcpcd.conf:

interface eth0

static ip_address=192.168.1.100/24

static routers=192.168.1.1

static domain_name_servers=192.168.1.1

Now the system will use a fixed IP address on every boot.

Installing Docker Engine

With the base system prepared, install the Docker Engine container runtime.

Adding the GPG Key

Download and add Docker’s official GPG key to verify binary integrity:

curl -fsSL https://download.docker.com/linux/$(. /etc/os-release; echo “$ID”)/gpg | sudo gpg –dearmor -o /etc/apt/trusted.gpg.d/docker.gpg

This completes the cryptographic verification steps.

Configuring the Repository

Next, configure access to Docker’s container repository:

echo “deb [arch=$(dpkg –print-architecture) signed-by=/etc/apt/trusted.gpg.d/docker.gpg] https://download.docker.com/linux/$(. /etc/os-release; echo “$ID”) $(lsb_release -cs) stable” | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

Now APT can install Docker packages.

Installing the Docker Packages

Update the package index and install the latest version of Docker:

sudo apt update

sudo apt install docker-ce docker-ce-cli containerd.io docker-compose-plugin

Enable Docker on startup:

sudo systemctl enable docker

The Docker Engine is now ready!

Managing the Docker Daemon

With Docker installed, customize the Engine configuration for improved security and adjust the daemon options for performance.

Securing the Docker Daemon Socket

Restrict access to the Docker daemon socket to prevent unauthorized container access:

sudo nano /lib/systemd/system/docker.socket

Modify the socket file permissions:

[Socket]

Runs as root only

User=root

 Only allow socket access to docker group

Group=docker

Reload and restart:

sudo systemctl daemon-reload

sudo systemctl restart docker

Now only the root user and docker group can access Docker Engine.

Configuring the Docker Daemon

Tune the daemon for efficient container execution:

sudo nano /etc/docker/daemon.json

Set helpful daemon directives:

json

{

  “exec-opts”: [“native.cgroupdriver=systemd”],

  “log-driver”: “json-file”,

  “log-opts”: {

    “max-size”: “100m”

  },

  “storage-driver”: “overlay2”

}

This config selects an appropriate cgroup driver, caps log sizes, and enables the overlay file system for containers.

Restart the daemon to apply the settings:

sudo systemctl restart docker

Optimizing Docker on the Raspberry Pi

While Docker functions on the Raspberry Pi, there are opportunities for optimization. Improve container builds, grant access to devices, and enable container auto start.

Setting Build Flags

When building container images, enable flags that optimize for the ARM architecture:

docker build –pull –no-cache -f \

  –build-arg TARGETOS=linux \

  –build-arg TARGETARCH=arm \

  –build-arg TARGETVARIANT=armv7

This speeds compile times significantly through caching and cross-compilation.

Granting Device Access

Containers need access to attached hardware like GPIO, I2C, and camera devices. Add users to hardware groups:

sudo usermod -aG video docker

sudo usermod -aG input docker

sudo usermod -aG gpio docker

Containers will run workloads using hardware smoothly.

Configuring Container Auto Start

Rather than manually run containers, enable auto start on reboot:

  1. Create a systemd service file
  2. Set container parameters like port bindings and volumes
  3. Enable auto start on reboot

This way containers launch reliably whenever the Pi boots up.

Deploying Applications as Containers

With Docker optimized, use containerization to encapsulate applications and simplify deployment.

Structuring a Dockerfile

Create a Dockerfile to describe container build steps:

dockerfile

FROM debian:stable-slim

RUN apt-get update && apt-get install -y \

    nginx

EXPOSE 80

CMD [“nginx”, “-g”, “daemon off;”]

This installs Nginx, copies a web file, opens the port, and sets the start command.

Building the Docker Image

Construct the container image based on Dockerfile instructions:

docker build -t webserver .

The image is now ready for distribution and execution.

Running the Web Server Container

Start the Nginx container and expose it on the Docker host network:

docker run -d -p 80:80 webserver

The web application is reachably on port 80.

Key Takeaways

Installing and configuring Docker on Raspberry Pi grants access to the container ecosystem. Key highlights:

  • Prepare the operating system through configurations and static IP assignment
  • Install Docker Engine packages from official repositories
  • Secure the Docker daemon socket to prevent unauthorized access
  • Optimize Docker for ARM architecture through build flags
  • Structure container environments with Dockerfiles
  • Simplify application deployment into containers
  • Automate container start on system boot

Docker enables portable and agile software delivery onto the Raspberry Pi platform.

Conclusion

Containerization with Docker allows Raspberry Pi users and developers to isolate applications, manage dependencies, and quickly build & ship projects. By installing the Docker Engine, optimizing for performance, and using containers for deployment, the Raspberry Pi can serve as a hub for learning, experimentation, and innovation. Docker simplifies running complex stacks reliably and efficiently on Raspberry Pi.

Frequently Asked Questions

  1. How do I check the Docker version on Raspberry Pi?
    Run docker -v to print the currently installed Docker version.

  2. What Docker base image should I use for Raspberry Pi containers?
    Start with a Debian or Ubuntu ARM base image like arm32v7/debian tailored to the architecture.

  3. Do I need to update Docker frequently?
    Yes, update Docker regularly by running sudo apt update && sudo apt upgrade to get the latest patches and features.

  4. How can I monitor Docker resource usage on my Pi?
    Use a tool like docker stats to view real time container resource utilization statistics.

  5. What is the best SD card for running Docker on Raspberry Pi?
    Use a class 10 microSD card from a quality brand like SanDisk Ultra with at least 16GB capacity.

  6. How do I check if the Docker service started properly?
    Check status via sudo systemctl status docker – it reports runtime errors if Docker failed.

  7. What user should run Docker containers?
    For security, restrict container processes to a non-root docker user rather than root.

  8. How do I remove unused Docker images and containers?
    Use docker system prune and docker volume prune to clean up old images, containers, volumes, and networks.

  9. What is the difference between Docker Engine and Docker Compose?
    Docker Engine is the base container runtime. Docker Compose simplifies launching multi-service app stacks via configuration.

  10. How do I enable the I2C interface through Docker?
    Add the –device=/dev/i2c-1 flag when launching containers that need I2C access.

  11. Can Docker containers access the Raspberry Pi GPU?
    Yes, use the –device=/dev/vchiq option to pass through the Video Core IV GPU.

  12. How do I configure auto restart for containers that exit?
    Use the Docker –restart unless-stopped option to automatically restart exited containers.

  13. What interface does Docker use to expose ports?
    Docker publishes ports onto the default docker0 bridge interface or the host networking stack.

  14. How do I mount external storage onto my Docker containers?
    Use the -v /local/path:/container/path argument when launching containers.

  15. Is Docker compatible with Raspberry Pi OS Lite?
    Yes, Docker and containers work on the Lite OS image but lack GUI tools for management.

  16. Can I control Docker remotely through SSH?
    Yes, SSH into the Pi and run docker and docker-compose commands to manage containers remotely.

  17. How do I remove old Docker containers to free up disk space?
    Remove exited containers with docker container prune and dangling images using docker image prune.

  18. Which is better for containers – Docker Compose or Kubernetes?
    For a single Pi, use Docker Compose. For cluster management across multiple Pis, Kubernetes is better suited.

  19. What interface does Docker use to expose ports?
    Docker publishes ports onto the default docker0 bridge interface or the host networking stack.

  20. Should I install Docker on the Raspberry Pi OS or in a Docker image?
    Installing Docker directly on top of the host Raspberry Pi OS allows tighter integration and the ability to leverage hardware capabilities like GPIO. Using a Docker image can simplify configuration but may limit access to devices.

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