Build a Cluster

EARLIER, WE MENTIONED the possibility of installing Docker containers on the Raspberry Pi. While they’re excellent at getting preconfigured applications running, there’s another aspect of Docker that suits the Pi’s low cost and low energy footprint very well: Swarm mode. In essence, it’s a simple way of setting up cluster computing, which combines multiple physical machines with networking to create a single logical machine. Hook up two Raspberry Pi 3 units as processing nodes, for example, and you’ll have eight ARM cores and 2GB RAM at your disposal. Scale it up, and you’ll outpace the processing power of the original Cray supercomputers with only a small investment.

Normally, this isn’t at all easy, as anyone whose high school computer lab had them set up a Beowulf cluster of tired Pentium 2 machines will attest. Thankfully, the software wizards at Hypriot have developed the Cluster Lab, a super-simple way to set up a Docker Swarm with several Raspberry Pi units. Check out the instructions at http://github. com/hypriot/cluster-lab. In essence, you simply need to flash a specific OS image to each node, tell them they’re part of a swarm, and they’ll find each other, and work together automatically. Now it’s just a question of what to do with your cluster...