Raspberry Pi Cluster – Part 1: The Hardware

For  a long time I had wanted my own Raspberry Pi cluster and I finally managed to get started. There will be five nodes, which will give me 20 cores to play with. The overall plan is to manage the nodes with Ansible and run a Kubernetes cluster on them.

Let’s start with putting these boards together. I quickly settled for using spacer bolts. There are special ones for Raspberry Pi available, but I just got some cheap ones from AliExpress, as shown below. They have two disadvantages, though. Firstly, their diameter is a little bit too big for the wholes in the PCB (printed circuit board). So I used a wood drill size 3 to extend the wholes by just a fraction of a millimeter. You can somewhat see the white left-overs from the drilling at the lower left whole in the picture below.

The second problem is that my spacer bolts are pretty short. So in order to avoid short circuiting things, I put insulation tape on top of the USB ports.

With these two small modifications I went ahead and assembled the Raspberry Pis into a nice stack.

As power supply I chose a 5-port 50 watts USB model from Aukey, which I got a while ago from Amazon when they were on special offer. Aukey does such promotions quite frequently, so if you can wait a bit, you will be able to safe a few bucks.

And this is what things look like connected (excluding network of course).

That’s it for today. Stay tuned for the next part in this series.

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