The King in Alice's Adventures in Wonderland said it best, "Begin at the beginning …." The general goal of HPC is either to run applications faster or to run problems that can't or won't run on a single server. To do this, you need to run parallel applications across separate nodes. Although you could use a single node and then create two VMs, it's important to understand how applications run across physically different servers and how you administer a system of disparate physical hardware.

With this goal in mind, you can make some reasonable assumptions about the HPC system. If you are interested in parallel computing using multiple nodes, you need at least two separate systems (nodes), each with its own operating system (OS). To keep things running smoothly, the OS on both nodes should be identical. (Strictly speaking, it doesn't have to be this way, but otherwise, it is very difficult to run and maintain.) If you install a package on node 1, then it needs to be installed on node 2 as well. This lessens a source of possible problems when you have to debug the system.

The second thing your cluster needs is a network to connect the nodes so they can communicate to share data, the state of the solution to the problem, and possibly even the instructions that need to be executed. The network can theoretically be anything that allows communication between nodes, but the easiest solution is Ethernet. In this article, I am initially going to consider a single network, but later I will consider more than one.

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