The Best Way To Install Docker on a Raspberry Pi and other IoT devices.

Docker has revolutionized the software development industry. It makes it possible for developers to develop containerized applications that are easier to scale and maintain than other applications.

This gives developers the ability to develop applications that:

• Require less overhead because containers require fewer system resources than traditional or other virtual machine environments.
• Are portable because the applications can be deployed quickly to multiple machines and hardware platforms.
• More consistent irrespective of the hardware they're running on. This is because containerized applications will run the same, regardless of where they're deployed.
• Efficient because it allows applications to be rapidly deployed, updated, and maintained.
  

But now the question is whether Docker can be installed on a Raspberry Pi. In this post, we'll look at this question in more detail.

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What is Docker Engine?

Docker is a software platform for building applications based on containers. These containers are small and lightweight environments that run in isolation but share the operating system kernel. 

One of the main challenges of modern software development is to develop applications that run on the same host but still be isolated from one another so that they don't interfere with each other's processes or maintenance.

Before Docker, a solution to this problem was implementing virtual machines which keep applications on the same hardware separate. The problem, though, with virtual machines is that they take a lot of system resources and each virtual machine requires its own operating system. They are also challenging to maintain and upgrade.

Containers solve this problem by isolating different parts of an application from each other. They're also lighter on resources than virtual machines and start up far quicker. In simple terms, they provide a highly efficient mechanism for combining the different components of an application into one while making it easier to update and maintain.

Because Docker simplifies the creation of containers and container-based apps, it plays a vital role in containerization and microservices.

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Can a Raspberry Pi Run Docker?

So, now the question is whether a Raspberry Pi can run Docker. The simple answer is yes; a Raspberry Pi can run Docker.

This wasn't always the case, though. Before 2016 people mainly used an operating system, Hypriot OS, which was specifically configured for using containers on Raspberry Pi.

Since 2016, though, Docker is officially available on Raspberry Pi. 

Best Way To Install Docker Engine on a Raspberry Pi

The Docker team now provides an official installation script for installing Docker on a Raspberry Pi device. As a result, users can download and execute the script by running the following command in their terminal: 

curl -fsSL https://get.docker.com | sh

This is far easier than previous ways, which relied on a very manual process which often meant building Docker from scratch on a Raspberry Pi. This process could take hours.

Once Docker is installed using the above command, there are still a few manual steps that are needed to get the best experience on the device.

The first is to set Docker to auto-start every time the Raspberry Pi is turned on or rebooted. To do this, the following command is needed:

sudo systemctl enable Docker

The next step is to enable the Docker client. This is because the Docker client can only be used by root or members of the Docker group. It's, therefore, necessary to add the relevant user to the Docker group. To do this, the following command is used: 

sudo usermod -aG docker username

Once Docker is installed and configured, users or able to create their own containers or download starter containers for their projects. The Raspberry Pi is a particularly good choice for building a Docker swarm. 

This means connecting several Raspberry Pis with one another instead of constructing a server structure. Each device then executes its own container, and these containers can be orchestrated with Swarm and Compose.

Another option is to use the Raspberry Pi as an Internet of Things device. And here, the JFrog Connect Container Update tool makes it easy to deploy and manage Docker containers remotely.

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The JFrog Connect Container Tool

The JFrog Connect Container Update tool is a system for deploying and managing over-the-air container updates on remote embedded Linux-based products in any environment and at any scale.

It offers the following features:

• It's simple and intuitive. It works out of the box with Docker images, and it has an easy deployment process that takes only a few seconds.
• It's secure. It's encrypted at rest and in-transit and pulls any data directly from DockerHub, AWS, Azure, or any other repository to the device through HTTPS.
• Automatic update rollback. In the case of a failure or other emergency detected by the device supervisor, the container deployment will automatically roll back to the last working container version.
• Smart deployment. It enables users to deploy a container or many containers to a specific device or group of devices while monitoring the deployment progress and the result.
• Robust. The tool ensures 100% robustness by deploying a tested image that includes the software and packages.
• Automatic order engine. The container update system ensures that each device, whether offline or online, will receive the deployed container updates in the order they were deployed. 
  

One of the main benefits of using over-the-air container updates is that bugs can be fixed, and the stability and performance of devices can be improved, which eliminates costly recalls and in-person maintenance. It also enables the ability to add new features after the release without requiring physical access to the device.

As a result, developers can ensure a faster time-to-market and test new features on selected devices while knowing that the devices will remain stable.

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The Bottom Line

Hopefully, this guide helped illustrate that Docker can be installed on a Raspberry Pi and provided the best way to do so. Once installed, it can be used as an Internet of Things device and, together with the JFrog Connect Container Update tool, be updated and maintained easily and efficiently.