My nixos configuration.

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
    ];
  boot.initrd.luks.cryptoModules = [ "aes" "sha256" "xts" ];
  boot.initrd.kernelModules = [
    "dm_snapshot" "kvm-intel" "usbhid"
    "ehci_pci"
    "ohci_pci"
    "xhci_pci" "hid_generic"
  ];
 
  boot.initrd.luks.devices = [{
    name = "crypt";
    device = "/dev/disk/by-uuid/9d6af03a-6f69-4fdc-92b8-c50536f23e3e";
    allowDiscards = true;
  }];

  fileSystems."/" =
    { device = "/dev/mapper/crypt";
      fsType = "btrfs";
      options = ["noatime" "nodiratime" "discard" "ssd" "space_cache"];
    };

  fileSystems."/boot" =
    { device = "/dev/disk/by-uuid/63C1-CCD0";
      fsType = "vfat";
      options = ["noatime" "nodiratime" "discard"];
    };


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

  networking.hostName = "exodus"; # 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/Prague";

  # List packages installed in system profile. To search by name, run:
  # $ nix-env -qaP | grep wget
  environment.systemPackages = with pkgs; [
    wget
    emacs25
    vim
    rsync
    firefox
    chromium
    libvirt
    docker
    git
  ];

  # List services that you want to enable:
  # Enable the OpenSSH daemon.
  services.openssh.enable = true;
  # Enable CUPS to print documents.
  # services.printing.enable = true;

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

  # Enable the KDE Desktop Environment.
  # services.xserver.displayManager.kdm.enable = true;
  # services.xserver.desktopManager.kde4.enable = true;
  services.xserver.desktopManager.kde5.enable = true;
  services.xserver.videoDrivers = [ "modesetting" ];

  # Define a user account. Don't forget to set a password with ‘passwd’.
  # users.extraUsers.guest = {
  #   isNormalUser = true;
  #   uid = 1000;
  # };
  users.extraUsers.aslaikov = {
    isNormalUser = true;
    uid = 1000;
    extraGroups = [ "wheel" "networkmanager" "docker" ];
  };

  # The NixOS release to be compatible with for stateful data such as databases.
  system.stateVersion = "16.09";

  # nixpkg.config.packageOverrides = pkgs: {
  #   freetype_subpixel = pkgs.freetype.override {
  #     useEncumberedCode = true;
  #   };
  # };
  virtualisation.docker.enable = true;
  virtualisation.docker.storageDriver = "btrfs";
}