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Docker Containers for Your Raspberry Pi

Compact PCs need compact apps

Martin Wimpress

Harrison Broadbent (opens new window) / Unsplash (opens new window)

Founded in 2008 with the aim of advancing computer education for all, Raspberry Pi (opens new window) is a cost-effective, compact computer a little larger than a credit card that can be plugged into any monitor and can process a variety of coding languages.

Marketed at anyone from experienced coders to children, Raspberry Pi has been used for a variety of clever projects, including creating Twitter bots (opens new window), automating homes (opens new window), and learning how to code (opens new window).

Pretty cool, right? Our team here at Slim.AI applauds the many uses of Raspberry Pis and has even toyed with them in our own home server setups. However, this compact hardware is not without drawbacks. The limited hardware specs mean that disk space and memory come at a premium, and they are best for running a single application at a time. Docker containers can mitigate these obstacles by providing a convenient place from which to store and launch entire applications, but setting up a containerized app on a Raspberry Pi present its own challenges

# What is Docker and How Can I Use it with Raspberry Pi?

A Docker Container (opens new window) is a standard unit of software that bundles up all elements of a piece of code, to ensure application transferability from one processor to another. This allows developers to isolate their application and run it within any environment.

With Raspberry Pi known for its simple configuration, many developers use them to conduct experiments. The same applies to Docker. With users able to package multiple different software types into one container, Docker containers are handy for allowing users to get creative with their code without having to worry about server configuration, library versioning, and other sys-admin–type tasks. Best of all, because everything in the container is self-contained (opens new window), the application is relatively isolated from the rest of the hardware’s operating system.

Additionally, if you need to scale beyond a single machine, containers allow you to scale your experiments effortlessly. You can deploy numerous Docker containers across numerous Pis using a wide variety of tools, and even coordinate complex application ecosystems. .

# Challenges of Deploying Docker with Raspberry Pi

Currently, the record for web servers running in single containers attached to a single Raspberry Pi stands at 2334 (opens new window). Think you can beat this record? In 2015, Docker was so interested to see who could challenge this record that they offered to pay for anyone who could beat it to attend DockerCon Europe! (Even though it’s 2021, and well past the days of that initial competition, if you find a way to beat it, don’t forget to visit our contact page and let us in on the good news!)

Although this is truly a vast amount of servers within one small piece of technology, it is important to be aware of the amount of memory and resources that a single container takes up. For this reason, it is imperative that users set quotas (opens new window) to limit the amount of resources that a single container can use. You can set such quotes using command-line flags (opens new window) that will effectively budget the amount of resources that each application can pull from the total available.

# Raspberry Pi OS Architecture Challenges

In 2020, Raspberry Pi updated their operating system (opens new window) to use a faster 64-bit version of the ARM architecture. This replaced their previous system, Raspbian.

Although Docker works on all editions of Raspberry Pi, you will want to ensure that you select the right variant for the images you plan to run. While the 32-bit edition will run on any board, the 64-bit edition offers maximum benefits to users of Raspberry Pi 3 and 4.

The new OS also comes in a desktop version, which allows full graphic features, and a lite version, which does not require a graphical interface to work. Ultimately, the lite feature is a benefit as it can reduce the space required to store memory.

# Docker Image Challenges

Docker images take up more space as you add layers to the image. However, there are some best practices (opens new window) that users can implement to ensure that their images do not get too bulky.

First, users can implement codes that clean up each layer of the image as they go. This must be done before each deployment of the code, before the layer gets finalized, or else the data itself isn’t removed. Through cleaning at each layer, the user can ensure that excess data is removed as they build their application file.

Additionally, it is important to minimize the number of layers altogether. By using multi-stage layers, users can debug each stage of their image without adding to the overall file size.

# Docker Security Challenges

Docker security is also a tremendous challenge that Raspberry Pi users face. Because users download OpenSource software to their containers, it is critical that users be cognizant of which libraries they are using in order to avoid users with malicious intent. Users should make sure that they use trusted, secure images and identify the source of all code that they download to their own equipment.

Along with being cautious of what you deliberately download to your Docker containers, it is important to be aware of what malware you are leaving yourself open to. For this reason, it is critical that users secure their container registries. When you use a Docker Trusted Registry (opens new window), you install everything behind your own firewall in order to prevent security breaches.

# Connect with fellow container enthusiasts in the Slim.AI Community

With millions of developers out there trying to solve the same problems that you are, it is critical that you join a community of like-minded developers to collaborate on answers to the industry’s most challenging questions. Join us in the Slim.AI community (opens new window) to learn about containers and contribute your ideas.

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