nixpkgs/nixos/doc/manual/installation/building-images-via-nixos-rebuild-build-image.chapter.md

Building Images with nixos-rebuild build-image

Nixpkgs contains a variety of modules to build custom images for different virtualization platforms and cloud providers, such as e.g. amazon-image.nix and proxmox-lxc.nix.

While those can be imported individually, system.build.images provides an attribute set mapping variant names to image derivations. Available variants are defined - end extendable - in image.modules, an attribute set mapping variant names to a list of NixOS modules.

All of those images can be built via both, their system.build.image attribute, and the CLI nixos-rebuild build-image. To build i.e. an Amazon image from your existing NixOS configuration:

$ nixos-rebuild build-image --image-variant amazon
$ ls result
nixos-image-amazon-25.05pre-git-x86_64-linux.vhd  nix-support

To get a list of all variants available, run nixos-rebuild build-image without arguments.