It is possible to install Ubuntu 14.04 to a native ZFS root pool. This procedure has been documented elsewhere, and this post is basically a rehash of the post at https://github.com/zfsonlinux/pkg-zfs/wiki/HOWTO-install-Ubuntu-14.04-or-Later-to-a-Native-ZFS-Root-Filesystem more as a reminder to myself of how to do this again. You may find it useful as well.

install ubuntu-14.04

apt-get install software-properties-common
apt-add-repository --yes ppa:zfs-native/stable
apt-get update
apt-get install ubuntu-zfs
apt-get install zfs-initramfs
modprobe zfs
dmesg | egrep "SPL|ZFS"

echo '# Create by-id links in /dev for zfs vdev. Needed by grub' > /etc/udev/rules.d/90-zfs-vdev.rules
echo 'KERNEL=="sd*[0-9]", IMPORT{parent}=="ID_*", ENV{ID_FS_TYPE}=="zfs_member", SYMLINK+="$env{ID_BUS}-$env{ID_SERIAL}-part%n"' >> /etc/udev/rules.d/90-zfs-vdev.rules

parted /dev/disk/by-id/scsi-35000c5005627e703
(parted) set 9 bios on

parted /dev/disk/by-id/scsi-35000c5005627d36f
(parted) set 9 bios on

zpool create -f -o ashift=12 rpool scsi-35000c5005627e703-part1 scsi-35000c5005627d36f-part1
zpool export rpool
zpool import -d /dev/disk/by-id rpool
udevadm trigger

zfs create rpool/ROOT
zfs create rpool/ROOT/ubuntu-1
mkdir /mnt/tmp
mount --bind / /mnt/tmp
rsync -avP /mnt/tmp/. /rpool/ROOT/ubuntu-1/.
umount /mnt/tmp

cat /dev/null > /rpool/ROOT/ubuntu-1/etc/fstab

vi /rpool/ROOT/ubuntu-1/etc/default/grub
comment out:
  #GRUB_HIDDEN_TIMEOUT=0
append:
  GRUB_CMDLINE_LINUX="boot=zfs rpool=rpool bootfs=rpool/ROOT/ubuntu-1"

for d in proc sys dev;do mount --bind /$d /rpool/ROOT/ubuntu-1/$d;done
chroot /rpool/ROOT/ubuntu-1/
update-grub
exit
for d in proc sys dev;do umount /rpool/ROOT/ubuntu-1/$d;done

for d in /dev/sd[a-b];do grub-install --boot-directory=/rpool/ROOT/ubuntu-1/boot $d;done

init 6