configuration.nix

{ config, pkgs, lib, ... }:

{

  networking.hostName = "wiloma";
  networking.domain = "wiloma.tech";

  i18n.defaultLocale = "fr_FR.UTF-8";
  i18n.supportedLocales = ["fr_FR.UTF-8/UTF-8"];
  time.timeZone = "Europe/Paris";

  services.openssh.enable = true;
  services.openssh.permitRootLogin = "yes";
  services.timesyncd.enable = lib.mkDefault true;

  #security.polkit.enable = false;
  
  environment.systemPackages = with pkgs; [
      
  ];

  users.mutableUsers = false;

  system.stateVersion = "20.03";
}

images.nix

let
  pkgs = import <nixpkgs> { };
  lib = pkgs.lib;
  toEval = modules:
    import <nixpkgs/nixos/lib/eval-config.nix> {
      system = pkgs.system;
      modules = [ ./configuration.nix ] ++ modules;
    };
  modules = {
    standalone = [{
      config = {
        fileSystems."/" = {
          device = "/dev/disk/by-label/nixos";
          fsType = "ext4";
          autoResize = true;
        };        

        boot = {
          loader = {
            systemd-boot.enable = true;
            efi.canTouchEfiVariables = true;
          };
        };
      };
    }];
  };
  evals = {
    standalone = let
      eval = toEval modules.standalone;
      name =
        "nixos-${eval.config.system.nixos.label}-${pkgs.stdenv.hostPlatform.system}";
    in import <nixpkgs/nixos/lib/make-disk-image.nix> {
      inherit lib name pkgs;
      config = eval.config;
      contents = [ ];
      partitionTableType = "efi";
      diskSize = 5000;
      format = "raw";
      postVM = ''
        extension=''${diskImage##*.}
        friendlyName=$out/${name}.$extension
        mv "$diskImage" "$friendlyName"
        diskImage=$friendlyName

        mkdir -p $out/nix-support

        ${pkgs.jq}/bin/jq -n \
          --arg label ${lib.escapeShellArg eval.config.system.nixos.label} \
          --arg system ${lib.escapeShellArg pkgs.stdenv.hostPlatform.system} \
          --arg logical_bytes "$(${pkgs.qemu}/bin/qemu-img info --output json "$diskImage" | ${pkgs.jq}/bin/jq '."virtual-size"')" \
          --arg file "$diskImage" \
          '$ARGS.named' \
          > $out/nix-support/image-info.json
      '';
    };
  };
  scripts = {
    standalone = pkgs.writeScript "run" ''
      #!${pkgs.stdenv.shell}

      file=$(cat ${evals.standalone}/nix-support/image-info.json | jq -r .file)
      cp $file ./nixos.qcow2
      chmod u+w nixos.qcow2

      #trap "rm -f nixos.qcow2" EXIT
      #${pkgs.qemu}/bin/qemu-system-x86_64 -nographic --cpu host --enable-kvm -hda nixos.qcow2
    '';
  };
in lib.mapAttrs (name: v:
  v // {
    run = scripts.${name};
    eval = evals.${name};
    modules = modules.${name};
  }) scripts

Makefile

.PHONY: run
run:
	$(shell nix-build images.nix --no-out-link)

.PHONY: build
build:
	nix-build images.nix --no-out-link