Failed to install NixOS 17.03 in ZFS. It stopped stage 1 because NixOS can not find zpool.

configuration.nix

{ config, pkgs, ... }:

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

  # Use the GRUB 2 boot loader.
  boot.loader.grub.enable = true;
  boot.loader.grub.version = 2;
  boot.loader.grub.device = "/dev/vda";
  boot.supportedFilesystems = [ "zfs" ];
  boot.loader.grub.zfsSupport = true;
  boot.zfs.forceImportRoot = false;
  boot.zfs.forceImportAll = false;
  boot.kernelParams = [
    "zfs_force=1"
  ];

  networking.hostId = "8425e349"; 
  networking.hostName = "nixos.tokyo"; # Define your hostname.

  # Select internationalisation properties.
  i18n = {
    consoleFont = "Lat2-Terminus16";
    consoleKeyMap = "jp106";
    defaultLocale = "en_US.UTF-8";
  };

  # Set your time zone.
  time.timeZone = "Asia/Tokyo";

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

  # 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;

  users.extraUsers.hyphon81 = {
    isNormalUser = true;
    extraGroups = [ "wheel" ];
    createHome = true;
    uid = 1000;
  };

  # The NixOS release to be compatible with for stateful data such as databases.
  system.stateVersion = "17.03";

}

hardware-configuration.nix

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

{
  imports =
    [ <nixpkgs/nixos/modules/profiles/qemu-guest.nix>
    ];

  boot.initrd.availableKernelModules = [ "ata_piix" "uhci_hcd" "virtio_pci" "sr_mod" "virtio_blk" ];
  boot.kernelModules = [ ];
  boot.extraModulePackages = [ ];

  fileSystems."/" =
    { device = "rpool/root/nixos";
      fsType = "zfs";
    };

  fileSystems."/home" =
    { device = "rpool/home";
      fsType = "zfs";
    };

  fileSystems."/boot" =
    { device = "/dev/disk/by-uuid/7153a80d-f996-4aa7-a87d-0935e0cab3c3";
      fsType = "ext4";
    };

  swapDevices =
    [ { device = "/dev/disk/by-uuid/dec80265-67ee-4884-8cdc-08f33c53d51e"; }
    ];

  nix.maxJobs = lib.mkDefault 3;
}

zpool history

[root@nixos:~]# zpool history
History for 'rpool':
2017-04-13.16:23:19 zpool create -o ashift=12 -o altroot=/mnt rpool /dev/vda3
2017-04-13.16:23:35 zfs create -o mountpoint=none rpool/root
2017-04-13.16:23:35 zfs create -o mountpoint=legacy rpool/root/nixos
2017-04-13.16:23:36 zfs create -o mountpoint=legacy rpool/home
2017-04-13.16:23:41 zfs set compression=lz4 rpool/home
2017-04-14.05:39:56 zpool import -R /mnt rpool
2017-04-14.05:53:23 zpool import -R /mnt rpool
2017-04-14.06:03:20 zpool import -R /mnt rpool
2017-04-14.06:34:26 zpool import -R /mnt rpool