build.sh

#!/usr/bin/env bash

set -e
set -u
PS4=" $ "
set -x

env -i \
	PATH="$PATH" \
	NIX_PATH=nixpkgs="$HOME"/tmp/nixpkgs/nixpkgs:nixos-config="$PWD"/configuration.nix \
	nixos-rebuild build-vm

./result/bin/run-nixos-vm

configuration.nix

# Edit this configuration file to define what should be installed on
# your system.  Help is available in the configuration.nix(5) man page
# and in the NixOS manual (accessible by running ‘nixos-help’).

{ config, pkgs, ... }:

{
  imports =
    [ # Include the results of the hardware scan.
      ./hardware-configuration.nix
    ];

  # Use the systemd-boot EFI boot loader.
  boot.loader.systemd-boot.enable = true;
  boot.loader.efi.canTouchEfiVariables = true;

  # networking.hostName = "nixos"; # Define your hostname.
  # networking.wireless.enable = true;  # Enables wireless support via wpa_supplicant.

  # Select internationalisation properties.
  # i18n = {
  #   consoleFont = "Lat2-Terminus16";
  #   consoleKeyMap = "us";
  #   defaultLocale = "en_US.UTF-8";
  # };

  # Set your time zone.
  # time.timeZone = "Europe/Amsterdam";

  # List packages installed in system profile. To search, run:
  # $ nix search wget
  # environment.systemPackages = with pkgs; [
  #   wget vim
  # ];

  # Some programs need SUID wrappers, can be configured further or are
  # started in user sessions.
  # programs.bash.enableCompletion = true;
  # programs.mtr.enable = true;
  # programs.gnupg.agent = { enable = true; enableSSHSupport = true; };

  # List services that you want to enable:

  # Enable the OpenSSH daemon.
  # services.openssh.enable = true;

  # Open ports in the firewall.
  # networking.firewall.allowedTCPPorts = [ ... ];
  # networking.firewall.allowedUDPPorts = [ ... ];
  # Or disable the firewall altogether.
  # networking.firewall.enable = false;

  # Enable CUPS to print documents.
  # services.printing.enable = true;

  # Enable sound.
  # sound.enable = true;
  # hardware.pulseaudio.enable = true;

  # Enable the X11 windowing system.
  services.xserver.enable = true;
  # services.xserver.layout = "us";
  # services.xserver.xkbOptions = "eurosign:e";

  # Enable touchpad support.
  # services.xserver.libinput.enable = true;

  # Enable the KDE Desktop Environment.
  # services.xserver.displayManager.sddm.enable = true;
  # services.xserver.desktopManager.plasma5.enable = true;
  services.xserver.displayManager.lightdm.enable = true;
  services.xserver.displayManager.lightdm.greeters.gtk.enable = false;
  services.xserver.displayManager.lightdm.greeters.web.enable = true;

  # Define a user account. Don't forget to set a password with ‘passwd’.
  # users.extraUsers.guest = {
  #   isNormalUser = true;
  #   uid = 1000;
  # };

  users.users.root.initialHashedPassword = "";
  users.users.alice =
  { isNormalUser = true;
    home = "/home/alice";
    description = "Alice Foobar";
    extraGroups = [ "wheel" "networkmanager" ];
  };

  services.mingetty.autologinUser = "root";

  # This value determines the NixOS release with which your system is to be
  # compatible, in order to avoid breaking some software such as database
  # servers. You should change this only after NixOS release notes say you
  # should.
  system.stateVersion = "18.03"; # Did you read the comment?

}

hardware-configuration.nix

# Do not modify this file!  It was generated by ‘nixos-generate-config’
# and may be overwritten by future invocations.  Please make changes
# to /etc/nixos/configuration.nix instead.
{ config, lib, pkgs, ... }:

{
  imports =
    [ <nixpkgs/nixos/modules/installer/scan/not-detected.nix>
    ];

  boot.initrd.availableKernelModules = [ "ata_generic" "ehci_pci" "ahci" "isci" "xhci_pci" "firewire_ohci" "usbhid" "usb_storage" "sd_mod" ];
  boot.kernelModules = [ "kvm-intel" ];
  boot.extraModulePackages = [ ];

  swapDevices = [ ];

  nix.maxJobs = lib.mkDefault 12;
  powerManagement.cpuFreqGovernor = lib.mkDefault "powersave";
}