Building a Render Farm with a Bitscope Blade Quatro - Plan of action

20 Dec 2016

The Bitscope Blade is from the same people who make the Bitscope Oscilloscope & Analyzer tools. It's a host board that allows you to host one to four raspberry Pi and provides power and connectivity. You can stack a series of blades into a chassis and power these from a shared supply.

Here's Bruce from Bitscope describing it in more detail.

BitScope Blade Power & Mounting Solutions for Raspberry Pi

Render farm Overview

Element14 invited me to take a look at these blades so I started by reading the above page. One of the suggestions was for a render farm for the open source 3D modelling and animation package blender. This seemed like a great way to prove out the system in a real-world scenario.

My farm will consist of 4 Pi with one acting as a controller node. That will connect to the USB external disk and have a secondary network connection (possibly wifi) so I can copy the files to be rendered and download any packages needed.

The are four key elements in a render farm:

Power
Network
Shared Storage
Configuration management

Power

The BitScope Blade provides the power to the Pi via the 40way sockets. The blade has a beefy switch mode power supply in the form of an LM2576HVLM2576HV and a few discrete components which can provide 3A for the Pi and any accessories. The supply can take anything from 9v to 48v as an input. There are some big capacitors to handle any rush of current when starting up. I hope to power the external disk from the same supply but I do have the option of powering that independently if required. I'll likely use a spare 1U ATX power supply to provide power to the blade and router as I can grab 12V of that for both of them.

Network

The network will be connected up with Cat 5e cables and an old 10/100 router.

Shared Storage

The control node will connect to a USB disk which will be shared over the network.

Configuration management

For four nodes the configuration of the nodes is straightforward and can be done manually, for a larger system you'd need to consider how configuration and monitoring can be automated. Some script files will likely be used to help with that.