One of the projects I currently work on at work, and have for the last few years is how to go from a blank stack of servers to a fully configured cluster with my companies software running on it. While some projects were starting and getting going in the open source field when I started this project 5+ years ago, a lot of them kept rewriting their API every minor version rev. That started my down a path that has now become a decently large internal network booting infrastructure, and managing interconnects to our inventory system as well as other systems such as Tenable Nessus. I recently was awarded my first patent! This one is specifically about how my system interacts with the inventory to dynamically assign systems as they come online to clusters.
My part of the code was all written in Java and continues to evolve as a platform, I hope to open source a good amount of it down the road. I started the project by reading the RFCs for DHCP/PXE and then writing code. I have grown to enjoy writing libraries and some project this way of adhering to the standard (more on that some other time). The general platform can handle ProxyDHCP PXE booting, and then uses iPXE to create menus and boot systems. I spent many hours debugging different vendors PXE code and BIOS vs UEFI to get all the systems to work. The platform now supports plugins for many different aspects of server configuration.
I could write page about small details I have learned a long the way; one issue that has been driving me crazy recently, if you want to ProxyDHCP instead of using your main DHCP stacks these days is Secure Boot. iPXE does not have a Secure Boot signed image, I have tried to get Microsoft to sign it but they will not unless you are selling a product using that the sign iPXE. I am not I just wanted it for internal use. That means you may want to use grub2 as your loader, but there is a bug that has been outstanding for over 6 years and makes ProxyDHCP with grub basically impossible, https://savannah.gnu.org/bugs/?55636 which is sad.