A Beowulf cluster is nothing more than a bunch of computers interconnected by Ethernet and running with a Linux or BSD operating system. A key feature is the communication over IP (Internet Protocol) that distributes problems among the boards. The entity of the boards or computers is called a cluster and each board or computer is called a node.

In this chapter, we will first see what is really required for each board to run inside a cluster environment. You will see examples of how to build a cheap and scalable cluster housing and how to modify an ATX power supply in order to use it as a power source. I will then explain the network interconnection of the Beowulf cluster and have a look at its network topology. The chapter concludes with an introduction to the microSD card usage for installation images and additional swap space as well as external network storage.

The following topics will be covered: