The Coolest Retro Raspberry Pi Cluster Around

What would you do with your own computing cluster? Running a local storage server or a self-hosted website are some very popular choices, but other people would prefer to use the compute power for experimentation. You could, for instance, run offline large language models or a Kubernetes cluster to support your personal projects.

However, the costs associated with building a private computing cluster keep most people from building one at home. As Spencer of the Spencer's Desk YouTube channel recently demonstrated, though, a cluster doesn’t have to be especially expensive. He built a four-node cluster using Raspberry Pi Compute Modules and a mini-ITX motherboard designed for cluster computing. It may not be as powerful as a traditional cluster, but it allows you to experiment with the same basic techniques on a budget.

The nodes consist of four Raspberry Pi Compute Module 4 (CM4) units, three equipped with 8 GB of RAM and one with 4 GB, all using onboard eMMC storage. These modules are mounted onto a Turing Pi 2 motherboard, a purpose-built mini-ITX platform that can host up to four compute nodes via SO-DIMM slots. The board also includes an onboard gigabit switch and a Baseboard Management Controller (BMC), allowing remote monitoring and independent power control of each node — features typically reserved for enterprise hardware.

To adapt the CM4 modules to the motherboard, Spencer used custom adapter boards, along with passive aluminum heatsinks and carefully applied thermal paste for efficient cooling. Power is supplied through an external 12V brick using a specialized Nano PSU adapter, avoiding the need for a bulky desktop power supply.

Rather than placing the cluster in an off-the-shelf case, Spencer designed a fully custom enclosure inspired by retro PC aesthetics. The case was 3D printed in modular sections using techniques that eliminate the need for support structures and improve surface finish. A textured print bed gave the exterior panels a premium look, while faux-wood accents — created using wood-infused filament and “fuzzy skin” slicer settings — add a distinctive vintage flair.

The cooling system consists of a quiet 92mm fan that pulls air through a dust filter and channels it through a narrow duct that directs airflow precisely over the heatsinks. Testing with smoke confirmed efficient airflow, and even under full load, the system maintained temperatures below 50°C.

A custom acrylic side panel adds another layer of polish, featuring etched scientific illustrations representing the four fundamental forces — each corresponding to one node. These nodes are named after physicists like Yukawa, Faraday, Fermi, and Newton to keep with the theme.

Spencer initially deployed a lightweight Kubernetes distribution (K3s) but later removed it after finding it unsuitable for pooling resources across nodes. Instead, the cluster now runs a mix of practical services directly on bare metal or via Docker. These include a Pi-hole DNS server, a Tailscale network for remote access, a lightweight web development environment, and a small Minecraft server.

One node runs a local large language model using Ollama, demonstrating that even modest hardware can handle AI workloads — albeit slowly. Meanwhile, the cluster contributes idle compute power to distributed science projects through BOINC, assisting in the search for pulsars.

Check out the video below to learn how you can build your own Raspberry Pi-powered computing cluster.