NixOS on ZFS: not mounting on reboot

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 GRUB 2 boot loader.
  boot.loader.grub.enable = true;
  boot.loader.grub.version = 2;
  # boot.loader.grub.efiSupport = true;
  # boot.loader.grub.efiInstallAsRemovable = true;
  # boot.loader.efi.efiSysMountPoint = "/boot/efi";
  # Define on which hard drive you want to install Grub.
  boot.loader.grub.devices = ["/dev/vda" "/dev/vdb"]; # or "nodev" for efi only
  boot.supportedFilesystems = ["zfs"];
  boot.zfs.enableUnstable = true;
 
  # Load additional hardware stuff
    hardware = {
        # Hardware settings
        cpu.intel.updateMicrocode = true;
        enableAllFirmware = true;
  };
  networking.hostName = "nixos"; # Define your hostname.
  networking.hostId = "8425e349";
# networking.wireless.enable = true;  # Enables wireless support via wpa_supplicant.
 
  services.dbus.enable = true;
  nixpkgs.config.allowUnfree = true;
  # Select internationalisation properties.
   i18n = {
     consoleFont = "Lat2-Terminus16";
     consoleKeyMap = "us";
     defaultLocale = "en_US.UTF-8";
   };
 
  # Set your time zone.
   time.timeZone = "Americas/Denver";
 
  # Enable the X11 windowing system.
    services.xserver = {
        enable = true;
        #videoDrivers = [ "intel" ];
        layout = "us";
        #xkbOptions = "eurosign:e";
        #synaptics = {
        #    enable = true;
        #};
 
        # Enable the KDE Desktop Environment.
        displayManager.sddm = {
            enable = true;
        #    autoLogin = {
        #        enable = true;
        #        user = "${mySecrets.user}";
        #    };
        };
        desktopManager.plasma5.enable = true;
    };
 
 
    # Use KDE5 unstable
    nixpkgs.config.packageOverrides = super: let self = super.pkgs; in {
        plasma5_stable = self.plasma5_latest;
        kdeApps_stable = self.kdeApps_latest;
  };
 
  # List packages installed in system profile. To search, run:
  # $ nix search wget
   environment.systemPackages = with pkgs; [
        wget
    vim
    curl
    firefox
    vlc
    partition-manager
    wirelesstools
    ark
    dolphin
    kdeFrameworks.kdesu
    kate
    okular
    oxygen
    oxygen-icons5
    oxygenfonts
    plasma-desktop
    plasma-nm
    plasma-workspace
    spectacle
    kdeApplications.kdialog
    manpages
    mkpasswd
    nox
    qt5Full
    smplayer
    spice
    sudo
   
   ];
 
   security.sudo = {
    enable = true;
    wheelNeedsPassword = true;
   };
 
  # Some programs need SUID wrappers, can be configured further or are
  # started in user sessions.
  # 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;
   networking.networkmanager.enable=true;
 
  # Enable CUPS to print documents.
  # services.printing.enable = true;
 
  # Enable sound.
  # sound.enable = true;
  # hardware.pulseaudio.enable = true;
 
  # Enable touchpad support.
  # services.xserver.libinput.enable = true;
 
  # Define a user account. Don't forget to set a password with ‘passwd’.
  # users.users.guest = {
  #   isNormalUser = true;
  #   uid = 1000;
  # };
    users.extraUsers.ikidd = {
      isNormalUser = true;
      extraGroups = ["wheel" "networkmanager"];
    };
 
  # 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 = "18.09"; # 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/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/md127";
      fsType = "ext4";
    };
 
  swapDevices = [ ];
 
  nix.maxJobs = lib.mkDefault 2;
}

Someinfo

[root@nixos:~]# zfs list
NAME               USED  AVAIL  REFER  MOUNTPOINT
rpool             4.80G  18.3G    96K  /rpool
rpool/home          96K  18.3G    96K  legacy
rpool/root        4.80G  18.3G    96K  none
rpool/root/nixos  4.80G  18.3G  4.80G  legacy
 
[root@nixos:~]# zpool status
  pool: rpool
 state: ONLINE
  scan: none requested
config:
 
        NAME        STATE     READ WRITE CKSUM
        rpool       ONLINE       0     0     0
          mirror-0  ONLINE       0     0     0
            vda2    ONLINE       0     0     0
            vdb2    ONLINE       0     0     0
 
errors: No known data errors
 
[root@nixos:~]# cat /mnt/etc/hostid | od -A none -t x4
 8425e349
 
[root@nixos:~]# cat /etc/hostid | od -A none -t x4
 8425e349