cluster

I've long been a fan of Pi clusters. It may be an irrational hobby, building tiny underpowered SBC clusters I can fit in my backpack, but it is a fun hobby.

And a couple years ago, the 'cluster on a board' concept reached its pinnacle with the Turing Pi 2, which I tested using four Raspberry Pi Compute Module 4's.

Because Pi availability was nonexistent for a few years, many hardware companies started building their own substitutes—and Turing Pi was no exception. They started designing a new SoM (System on Module) compatible with their Turing Pi 2 board (which uses an Nvidia Jetson-compatible pinout), and the result is the RK1:

A few months ago someone told me about a new Raspberry Pi Compute Module 4 cluster board, the DeskPi Super6c.

You may have heard of another Pi CM4 cluster board, the Turing Pi 2, but that board is not yet shipping. It had a very successful Kickstarter campaign, but production has been delayed due to parts shortages.

tl;dr: This website is currently being hosted off-grid, on a cluster of Raspberry Pis, via 4G LTE—or at some points through the same tunnel via WiFi if signal strength gets too low. Here's the GitHub repo for the project.

Note: The website was down for a few hours this morning, as shortly after this post I started getting a 40-50 Mbps flood of POST requests (over 6 million in a 30 minute time frame)... and yeah, no way the little Pi cluster could handle that. Thanks, Internet. It's back up through Cloudflare now, and I'll post more on this 'fun' experience later.

A couple weeks ago, after months of preparation, I took my 4-node Turing Pi 2 cluster (see my earlier review) to my cousin's farm, and ran this website (JeffGeerling.com) on it, live on the Internet—completely disconnected from grid power or hard-wired Internet.

Last year I spent a bit of time building a Kubernetes cluster with the original Turing Pi. It was fun, and interesting, but ultimately the performance of the Compute Module 3+ it was designed around led me to running my homelab off some newer Pi 4 model B computers, which are at least twice as fast for almost everything I run on them.

So this year, I was excited when the folks at Turing Pi sent me a Turing Pi 2 to test drive. And the board arrived just in time for Patrick Kennedy from ServeTheHome to challenge me to a cluster build-off at Supercomputing '21! Check out his ARM cluster build here.

After I posted my Raspberry Pi Blade server video last week, lots of commenters asked what you'd do with a Pi cluster. Many asked out of curiosity, while others seemed to shudder at the very idea of a Pi cluster, because obviously a cheap PC would perform better... right?

Before we go any further, I'd say probably 90 percent of my readers shouldn't build a Pi cluster.

But some of you should. Why?

Well, the first thing I have to clear up is what a Pi cluster isn't.

Note: This blog post corresponds to my YouTube video of the same name: Why would you build a Raspberry Pi Cluster?. Go watch the video on YouTube if you'd rather watch the video instead of reading this post!

A few months ago, in the 'before times', I noticed this post on Hacker News mentioning the Turing Pi, a 'Plug & Play Raspberry Pi Cluster' that sits on your desk.

It caught my attention because I've been running my own old-fashioned 'Raspberry Pi Dramble' cluster since 2015.

So today, I'm wrapping up my Raspberry Pi Cluster series with my thoughts about the Turing Pi that I used to build a 7-node Kubernetes cluster.

Video version of this post

This blog post has a companion video embedded below:

At this point, I've showed you how you can use the Turing Pi as a Kubernetes cluster to run different things. I barely scratched the surface of what's possible with Kubernetes, but I'm planning on doing another series exploring Kubernetes itself later this year. Subscribe to my YouTube channel if you want to see it!

In this post, I'm going to talk about the Turing Pi's performance. I'll compare it to a more traditional Raspberry Pi cluster, my Pi Dramble, and talk about important considerations for your cluster, like what kind of storage you should use, or whether you should run a 32-bit or 64-bit Pi operating system.

As with all the other work I've done on this cluster, I've been documenting it all in my open source Turing Pi Cluster project on GitHub.

Video version of this post

This blog post has a companion video embedded below:

This is the third video in a series discussing cluster computing with the Raspberry Pi, and I'm posting the video + transcript to my blog so you can follow along even if you don't enjoy sitting through a video :)

This post is based on one of the videos in my series on Raspberry Pi Clustering, and I'm posting the video + transcript to my blog so you can follow along even if you don't enjoy sitting through a video :)

In the first episode, I talked about how and why I build Raspberry Pi clusters.

I mentioned my Raspberry Pi Dramble cluster, and how it's evolved over the past five years.

I will be posting a few videos discussing cluster computing with the Raspberry Pi in the next few weeks, and I'm going to post the video + transcript to my blog so you can follow along even if you don't enjoy sitting through a video :)

This is a Raspberry Pi Compute Module.

And this is a stack of 7 Raspberry Pi Compute Modules.