Appendix A. Building a Raspberry Pi Kubernetes Cluster
While Kubernetes is often experienced through the virtual world of public cloud computing, where the closest you get to your cluster is a web browser or a terminal, it can be a very rewarding experience to physically build a Kubernetes cluster on bare metal. Likewise, nothing compares to physically pulling the power or network on a node and watching how Kubernetes reacts to heal your application to convince you of its utility.
Building your own cluster might seem like both a challenging and an expensive effort, but fortunately it is neither. The ability to purchase low-cost, system-on-chip computer boards as well as a great deal of work by the community to make Kubernetes easier to install mean that it is possible to build a small Kubernetes cluster in a few hours.
In the following instructions, we focus on building a cluster of Raspberry Pi machines, but with slight adaptations the same instructions could be made to work with a variety of different single-board machines.
The first thing you need to do is assemble the pieces for your cluster. In all of the examples here, we’ll assume a four-node cluster. You could build a cluster of three nodes, or even a cluster of a hundred nodes if you wanted to, but four is a pretty good number.
To start, you’ll need to purchase (or scrounge) the various pieces needed to build the cluster. Here is the shopping list, with some approximate prices as of the time of writing: