NixOS offline installer demo (untested since 21.05)

How to build

To build the installer with the <nixpkgs> in your NIX_PATH, just do:

nix-build installer-iso.nix

To build the installer with the <nixpkgs> from the niv sources in nix/sources.json, do:

nix-build

How to test in qemu

qemu-img create -f qcow2 /tmp/qemu-mydisk.img 40G
qemu-system-x86_64 -enable-kvm -boot d -hda /tmp/qemu-mydisk.img -m 2000 -bios $(nix-build '<nixpkgs>' -A pkgs.OVMF.fd --no-out-link)/FV/OVMF.fd -net none -cdrom result/iso/*.iso

Interesting files:

• installer-iso.nix: This file assembles the NixOS configs and emits an installer ISO derivation.
• installer-configuration.nix: This image contains the other image and all the interesting scriptery to automate the offline installation.
• install-configuration.nix: This configuration is used by nixos-generate-config during installation. Customize this to your needs.
  • This must stay one file. During installation, the hardware-configuration.nix is still automatically generated. After installation, you may add the generated hardware-configuration.nix to your imports = [ ... ]; configuration field. Having it in during installation risks the functioning of the installer, because it is hard to predict what dependencies it will contain.