[tylerjl]

> [...] am I understanding correctly that nix could be used instead of packer to generate a vm image/template for proxmox(or whatever hypervisor)?

That's correct, although as you mention later, it's limited to NixOS. It's an unfortunate constraint given how tremendously powerful it is, but the limitation makes sense. nixos-generators is literally a nix function that accepts a NixOS configuration and operates on the nix value in order to construct the VM image, so it wouldn't work quite the same without nix at the core.

Because nix "knows" about the total definition of the system, nixos-generators can do wonderful things like construct an AMI image or VMWare image without talking to any hypervisor APIs or cloud APIs at all - it knows how to construct the system from the "ground up" and you just end up with a big disk image file after the appropriate `nix build ...` command, no AWS keys or running Proxmox API required.

It's a tradeoff, to be sure. But if the use case fits - which for us, it does quite well - you can be outrageously productive. Adding an entirely new image format takes as long as typing a new line in `flake.nix`, and I leverage a common NixOS module between all the image types to invoke a quick and easy local qemu VM when I'd like to experiment locally.

It's become hard to imagine what managing a "normal" system would be like with the features I get by baking it all into a NixOS configuration.