Universal Blue’s build system (not Blue-Build) is pretty clear, and self documenting. I maintained a personal fork of Bluefin for a while, and it was easy to understand!
Honestly? Immersing myself headfirst into Nix/NixOS, which has been fun and worthwhile.. but I’m not convinced it’s really “better,” at least for my needs.
And the fact that it’s ever so slightly easier to build and deploy a NixOS VM from scratch on a Proxmox VE server than to build and deploy a CoreOS VM using Ignition (also on Proxmox).
But it’s probably worth it for me to switch back, at least for now. It takes maybe 10-15 minutes to build a bootable Bluefin fork native container image with GitHub Actions, but a relatively basic NixOS+ Plasma 6 image took closer to 60 minutes and came out to over 8 GB compressed…
Interesting, I _just_ went from NixOS to Bluefin. I took home-manager with me, though, which gives me just enough Nix without the NixOS headaches (mainly around processes daring to bring "foreign" binaries into the system). My honeymoon period with Nix lasted about six months and was pretty quickly over. I stuck with NixOS for about 18 months only out of laziness of not wanting to set something else up. I really like this new stack, though. Time will tell if it's actually better.