Migrating my NAS from CoreOS/Flatcar Linux to NixOS

In this article, I want to show how to migrate an existing Linux server to NixOS — in my case the CoreOS/Flatcar Linux installation on my Network Attached Storage (NAS) PC. I will show in detail how the previous CoreOS setup looked like (lots of systemd units starting Docker containers), how I migrated it into an intermediate state (using Docker on NixOS) just to get things going, and finally how I migrated all units from Docker to native NixOS modules step-by-step. If you haven’t heard of NixOS, I recommen