Before we begin, there are some common things you should be reminded of.
Make backups For anything that isn't trivial to reproduce, you should make backups. Back up the image you use on the Raspberry Pi, and back up every package you install that doesn't come out of a default repository. When building software for science, we have to build most of it by hand, even if it's available pre-built.
Benchmark everything How is your cluster running? If a user says things are slow, how can you check? Is upgrading that library worth it? Will code run faster or slower, or the same? Benchmark everything and keep records.