You might already have been aware of Raspberry Pi Cluster’s usefulness for learning, experimentation, and making something innovative. If you have never heard about it, then let’s just say it’s one wise investment that can boost your skills and improve your local computer systems’ performance like no other.

But why would you need a Raspberry Pi cluster when you can run the same processes with your typical desktop/laptop/server? This article will provide 12 Raspberry Pi cluster uses cases and explain why you might want to get it for your homelab or for your business.

Why clusters?

The idea of a cluster is not new and has been around for quite some years now. Earlier, universities built clusters for research and development purposes. Nowadays, cluster computing gained popularity as developers, researchers, and data scientists have begun to explore new technologies and doing large “jobs” at home instead of the cloud. With the abundance of low-cost single-board computers, this approach amounts to a form of “Home Super Computer.” Long resource-intensive projects can create frustrating delays in any workflow, from video encoding to 3D renders, to data parsing and mining, to CI/CD pipelines. All of it can bog down even the most intense work machines. It also makes great sense economically to run resource-intensive tasks locally instead of a cloud in certain circumstances.

Cloud-native technologies

Because of the complexities behind it, many people often misunderstand the concept of a cloud computing. A popular misconception is that a cloud is just someone else’s computer. Well, the cloud system is not that simple. It involves numerous computers that form clusters interconnected with a network. If you wish to create your personal cloud system, you need at least three computers. Of course, you can emulate cloud systems by using virtual machines or simply using cloud providers. Though, there is a difference in managing and provisioning a cloud system on a bare-metal cluster. You can’t just run many VMs on one CPU and see the same issues with latency, concurrency, and resource usage as you would on an actual cluster.

Managing bare metal server instead of virtual machines requires more disciplines in provisioning, networking, and orchestration. Those three skills are very helpful in many modern IT jobs.

– Jeff Geerling

Another thing, you have full control over performance, setting, and features on a bare-metal cluster. The principle of learning cluster computing on hardware is why Los Alamos built a cluster of Raspberry Pis.

Why Raspberry Pi?

The answer is simple. By far, Raspberry Pi is the most popular single-board computer and well known for its affordable price. The Raspberry Pi community and software ecosystem are immense. The newest Raspberry Pi model offers gigabit ethernet, USB 3, and two, four, or eight gigabytes of RAM and keeps your electricity bills low. That is also true that you can build a cluster using Dell or HP servers and even old laptops. You can even get better performance and power efficiency per dollar, but imagine the amount of space you need for this. Imagine all these cooling fans working all the time and throwing air into your face. Raspberry Pi cluster gives you simplicity but also compactness, mobility, and extreme ease of scale.

Raspberry Pi cluster use cases

Let me put this succinctly – the Raspberry Pi is a Linux server. If you write code, or “do DevOps” for a day-job, you have a use-case.

– Alex Ellis

1. Learn, experiment, upskill

If your eyes are on the large salaries in the IT Industry and you would like a piece of the pie then a Raspberry Pi cluster is the best way to learn anything related to servers, networking, distributed systems, and security. Use a Raspberry Pi cluster to learn Linux or learn how to handle a MySQL or Postgres database. Learn how to install an Apache server or how to do scripting in BASH, Python, and other scripting languages to make those cluster nodes interoperate. Learn programming, managing resources in Linux. Learn how to make and manage your own cloud service. 

A Raspberry Pi cluster also allows you to learn Docker, Kubernetes, Serverless. Or how to turn all the cluster nodes’ resources into one supercomputer with the help of simultaneous processing software like OpenMPI. Deploy Kubernetes and containers almost instantly to learn how to do the same when you’ll be employed in a large corporation. A Raspberry Pi cluster will keep you learning for years on end as Linux and cloud native are vast and interesting ecosystems.

Everything I know about Kubernetes I learned from a cluster of Raspberry Pis

– Jeff Geerling

2. Make Your Very Own Homelab

You can build a homelab out of a Raspberry Pi cluster. If you are a software developer you can deploy versions of your software with Docker or Kubernetes, host your own private GitHub system, fast-compile different versions of your software at the same time using the resources of several cluster nodes at once. The more nodes the Raspberry Pi cluster has the faster it will perform in a shared-resource environment.

Make a database and webserver to test your website development outcome properly before releasing it to your clients. You can deploy several hosting environments with different configurations to see if your web project can handle older MySQL versions – for example. Or test versions of software to be implemented in your company to see how they will behave. Simulate multiple users with multiple use cases and monitor bugs and traffic to make sure the final product is stable and bullet-proof.

3. Self-Hosted Private Cloud

A Raspberry Pi cluster is the way to go if you want your own internal private cloud. Say you work for a company with hundreds or thousands of employees and you want to implement a cloud solution to be used by those employees for backup, CRM hosting, storing documentation, file sharing, or pushing new versions of modified files in a place where collaboration is crucial and you need to have access to older versions of those files and at the same time not to worry about privacy issues. You don’t need to run a ”bare metal” beast the size of a fridge to do this. A Raspberry Pi cluster is cheaper and fits in the corner of your office. You can use it to host your private cloud, version control system, backup system, and more – all in one.

The benefits of hosting your own private cloud are that you don’t depend on a third party to regulate costs and hold your private data and you can upscale the hardware in a few hours if needed.

4. Host Your Own Web Server

If you plan to serve web pages to the population of your geographic region it makes sense to use a server hosted in that region. It makes even more sense to host your own web server if you plan to reduce costs. A Raspberry Pi cluster can easily be made into a web server. Attach external storage of the desired size and install the LAMP packages. The security of the cluster is at your fingertips. You can use Graphana to visually monitor it, install CPanel for your clients, use QoS to modulate bandwidth and user accounts to grant resources as you wish. The best thing is you can offer both shared and dedicated web hosting options with the same cluster. If you need more resources because your client base has been recently enlarged you can always install new nodes on the Raspberry Pi cluster without any downtime. All being said even Raspberry Pi Foundation hosted their Raspberry Pi 4 launch site on a cluster of Raspberry Pis that served huge amount of traffic.

5. NAS and File Sharing in a Company or at home

There are several ways you can use a Raspberry Pi cluster to make shares for your colleagues or employees. Samba is a great tool and it can connect your LAN PCs regardless of what operating system they use. You can also host a NAS on the Raspberry Pi cluster and store large files like presentation videos, software kits, accounting PDFs, or backups. Each person in the company or in a family can have its own space on the cluster and you can assign different share sizes to your users. The cluster will also let your PCs communicate with one another internally. Bandwidth usage can be set and monitored so as not to clog the data transfers of other users. This means that hundreds of people can use the same Raspberry Pi cluster, all at the same time; to store and share files from within the office or – with the help of a VPN – from the comfort of their home.

6. Handle Heavy Loads

Some work environments require powerful computing resources to be available. If you are a programmer you know that the larger your project, the more time it takes to compile. You can make your very own compile farm and assign all the Raspberry Pi cluster nodes to work at the same time on the same task. Or you can give three nodes a task, and four other nodes a different task. Juggle with resources as you please. A Raspberry Pi cluster can handle heavy loads. ARM CPUs are known to perform well at such tasks and the more nodes you add to your Raspberry Pi cluster, the more multicore resources you have. And since a Raspberry Pi module is cheap enough and small in size, you can add as many as you like. You can use Docker or Kubernetes to handle specific tasks or parallel processing software to do the same. Why clog your laptop CPU for hours when you can do the same in a fraction of that time by using a Raspberry Pi cluster?

7. Fast multimedia conversion station

Most photographers, video editors, and 3D artists spend thousands of dollars on multimedia-capable PCs. The reasoning is that you can do the work and render it on the same device. But you can start much cheaper by using a regular laptop for work and a Raspberry Pi cluster for processing. Transfer your huge, raw image files on the cluster and let it batch convert them, resize them, apply filters and – generally – do the work for you. The same goes for converting huge video files much faster than an expensive PC could ever do. Render 3D files by using several CPUs and RAM modules at once. Or do all three at the same time while watching TV series on your old laptop. When the task is finished you can get notified by e-mail or sound or light and transfer the output back to your laptop. The more cluster nodes you use, the more resources you have at your disposal and the faster the process ends.

8. Build Your Own Supercomputer

Having access to parallel computing resources costs a lot. If you are doing research and use statistics a lot, you must know R is not only open-source but also highly customizable through plugins. R does statistical computations faster, on larger databases and free of charge, unlike Strata or SPSS. But R – like any other statistical software – tends to be resource-intensive. The more entries in your database, the more time it takes for the statistical software to output a result. That is why using a cluster for such tasks is recommended – it gives you access to several CPUs and gigs of RAM to do the work faster. The thing is access to supercomputers is hard to get, it’s charged by the hour and number of resources you need and sometimes you have to wait in line. With a Raspberry Pi cluster you can spend that money on hosting your very own supercomputer. Cheap, scalable, low on power consumption and noise. You can do your R computations on it, locally and for free, and you don’t have to wait in line to do so.

9. Minecraft and other games server

If you are a gamer and have already spent most of your cash on a decent gaming PC chances are you won’t afford an online server to host your own private world there. With a Raspberry Pi cluster you don’t need to spend a lot of money and you can host all your game servers on it. Give your friends a world in Minecraft. Battle monsters together in Lineage or hunt each other down in Rust. If the game has a server component, a Raspberry Pi cluster can run it smoothly.

10. CI/CD pipeline

If you use Ansible a lot and need a version-control system to debug your code you can use a Raspberry Pi cluster to easily set up such an environment. It can handle push and pull requests in companies of hundreds of users and this way you can keep your code in a closed environment and not somewhere online where it could escape into the wild. If you need to access the server from an IP that is not in your whitelist you can use your firm’s VPN to get access to that code from your home computer. Install GitLab and grant access rights to your developers. It doesn’t matter if you develop with Ansible or PHP or just edit large numbers of documents that need a version control system; the Raspberry Pi cluster can handle all of these and all at once.

11. Use a Raspberry Pi cluster for home automation

In the past years more and more households became automated as microcontrollers and automation hardware became cheaper. It costs a few hundred dollars to make your entire home automated. From lights to self-moving blinds to wifi plugs. Your garage door opens and closes by itself, your doorbell has a video feed, your baby monitor plays soothing music if a certain decibel level is reached by your kid’s screams. And all this can be in turn handled by a Raspberry Pi cluster. All those electronic appliances and doors need to have a central brain that watches and handles them. A Raspberry Pi cluster can be turned into an all-purpose automation center. It can send WiFi commands to your wall plug to activate your coffee machine then close it after three minutes when the coffee downstairs is done and poured into your cup. It can send you an e-mail after that or tune into your favorite radio station. Open the TV to your local news channel, turn on the oven, open the blinds as stair sensors “feel” you heading towards the bathroom. It can adjust lights, water temperature, shower pressure, and play music at the same time. A cluster can open the entrance door for you, unlock your car, reheat your driver’s seat, even read the news for you out loud. Logs, reports, appliance statistics – it can generate them all and inform you periodically about them.

12. All of the above

Because yes – a Raspberry Pi cluster can host and do all of the above on the same machine. Convert your movies while hosting a game server and a cloud at the same time. Learn Linux on the same cluster that holds your NAS and you can do so without affecting the other operations of the Raspberry Pi cluster. Experiment on the same multiple-node machine that holds your backups without the fear of losing them while doing so. Work faster and store data in a safe way.