{ config, lib, pkgs, modulesPath, desktop, username, ... }: {
  imports = [ ];
  nixpkgs.config.allowUnfree = false;

  boot.initrd.availableKernelModules = [ "ata_piix" "ohci_pci" "ehci_pci" "ahci" "sd_mod" "sr_mod" ];
  boot.initrd.kernelModules = [ ];
  boot.kernelModules = [ ];
  boot.extraModulePackages = [ ];

  fileSystems."/" = {
    device = "/dev/disk/by-label/ROOT";
    fsType = "ext4";
  };

  networking.useDHCP = lib.mkDefault true;
  nixpkgs.hostPlatform = lib.mkDefault "x86_64-linux";
  virtualisation.virtualbox.guest.enable = true;
  time.timeZone = "Asia/Tokyo";
  networking.hostName = "nixos-vm-01";

  boot.loader.grub = {
    enable = true;
    device = "/dev/sda";
    useOSProber = true;
  };

  networking.firewall.allowedTCPPorts = [ 22 ];
}