Abstract
This post is the first one of a series where I explain how to build a Linux cluster. The cluster has 6 RapsberryPi 4 Model B 2GB nodes. They are powered over ethernet by a switch.
Background
Back at university, I decided to learn about distributed systems1 by building my own Linux cluster. Then, I started collecting the main pieces:
- Five fans
- One 19" rack
- One ATX power supply
- One switch with at least 8 ports
- Six MicroSD cards of 16GB each
- Six RapsberryPi 4 Model B with 2GB of RAM
I 3D printed the cluster, which is the Raspberry Pi Server Mark III case.
However, despite having all pieces, I never assembled it. The reason was that I wasn’t comforatble powering the whole thing using an ATX power supply. It just didn’t feel secure.
Eventualy, I abanoned the project.
Nowadays
In October 2026, I jumped back to the cluster. With some savings, I acquired six power over ethernet hats for the nodes together with a new switch that supported this technology.
The result is a clean and secure setup, with just 6 ethernet cables and a single power cable comming out of the switch.
Specs
The cluster has six nodes with the following hardware:
| Component | Specification |
|---|---|
| Nodes | 6 Raspberry Pi 4 Model B boards |
| Memory | 2 GB per node, 12 GB total |
| Storage | 16 GB microSD per node, 96 GB total |
| Power | 6 Power over Ethernet (PoE) HATs and one PoE switch |
| Network | 6 Ethernet cables connecting the nodes to the switch |
| Enclosure | 3D-printed Raspberry Pi Server Mark III case |
Next steps
The next episode will explain how to setup previous infrastructure as code using popular tools such as Ansible.
A distributed system is a collection of independent computers (called nodes) that communicate and coordinate over a network to look and act like a single, unified program to the end user ↩︎