anchor.diff:        mkdir -m 755 -p $targetRoot/var
         mount --bind $targetRoot/ephemeral0/var $targetRoot/var
   
  +      mkdir -p /unionfs-chroot/ro-nix
  +      mount --rbind $targetRoot/nix /unionfs-chroot/ro-nix
  +
  +      mkdir -p /unionfs-chroot/rw-nix
         mkdir -m 755 -p $targetRoot/ephemeral0/nix
  -      mount -t aufs -o dirs=$targetRoot/ephemeral0/nix=rw:$targetRoot/nix=rr none $targetRoot/nix
  +      mount --rbind $targetRoot/ephemeral0/nix /unionfs-chroot/rw-nix
  +      unionfs -o allow_other,cow,nonempty,chroot=/unionfs-chroot /rw-nix=RW:/ro-nix=RO $targetRoot/nix
       '';
  +
  +    boot.initrd.supportedFilesystems = [ "unionfs-fuse" ];
       */
   
     # Since Nova allows VNC access to instances, it's nice to start to
  
positive.code:   # Put /tmp and /var on /ephemeral0, which has a lot more space.
    # Unfortunately we can't do this with the `fileSystems' option
    # because it has no support for creating the source of a bind
    # mount.  Also, "move" /nix to /ephemeral0 by layering an AUFS
    # on top of it so we have a lot more space for Nix operations.
    /*
    boot.initrd.postMountCommands =
      ''
  
negative.code: 
    boot.kernelParams = [ "console=ttyS0" ];
  
    boot.loader.grub.version = 2;
    boot.loader.grub.device = "/dev/vda";
    boot.loader.grub.timeout = 0;
  