Re-initialise GRUB for non-bootable UEFI zfs 16.04 installation

Largely cribbed from the ZFS installation instructions at https://github.com/zfsonlinux/zfs/wiki/Ubuntu-16.04-Root-on-ZFS, here are the steps I used to get my system working again.

boot-repair did not work.

Step 1: Prepare The Install Environment

1.1 Boot the Ubuntu Live CD, select Try Ubuntu Without Installing, and open a terminal (press Ctrl-Alt-T).

1.2 Optional: Install the OpenSSH server in the Live CD environment: If you have a second system, using SSH to access the target system can be convenient.

$ sudo apt-get --yes install openssh-server

Set a password on the “ubuntu” (Live CD user) account:

$ passwd

Hint: You can find your IP address with ip addr show scope global. Then, from your main machine, connect with ssh ubuntu@IP.

1.3 Become root:

# sudo -i

1.4 Install ZFS in the Live CD environment:

# apt-add-repository universe
# apt update

(ignore errors about moving an old database out of the way)

# apt install --yes debootstrap gdisk zfs-initramfs

Step 2: Discover available ZFS pools

2.1 Check if ZFS pools are already imported

# zpool list
# zfs list 

2.2 If it says "no datasets available" then skip to Step 3. If either of those commands brings up a list of pools, we need to export the zfs pool so we can mount it in a different directory so we can chroot to it

# zpool export rpool

Step 3: Chroot into ZFS pool

3.1 Import pool to non-default location. The -N flag (don’t automatically mount) is necessary because otherwise the rpool root, and the rpool/root/UBUNTU pool, will both try to mount on /mnt

# zpool import -N -R /mnt rpool

3.2 Mount the root system

# zfs mount rpool/ROOT/ubuntu

3.3 Mount the remaining file systems

# zfs mount -a

3.4 Bind the virtual filesystems from the LiveCD environment to the new system and chroot into it:

# mount --rbind /dev  /mnt/dev
# mount --rbind /proc /mnt/proc
# mount --rbind /sys  /mnt/sys
# chroot /mnt /bin/bash --login

Note: This is using --rbind, not —bind.

Step 4: Re-initialise EFI partitions on all root pool components

4.1 Check the wildcard gets the correct root pool partitions:

# for i in /dev/disk/by-id/*ata*part3; do echo $i; done

4.2 Add an entry for /boot/efi for each disk to /etc/fstab for failover purposes in future:

# for i in /dev/disk/by-id/*ata*part3; \
      do mkdosfs -F 32 -n EFI ${i}; \
      echo PARTUUID=$(blkid -s PARTUUID -o value \
      ${i}) /boot/efi vfat defaults 0 1 >> /etc/fstab; done

4.3 Mount the first disk

# mount /dev/disk/by-id/scsi-SATA_disk1-part3 /boot/efi

4.4 Install grub

# grub-install --target=x86_64-efi --efi-directory=/boot/efi \
      --bootloader-id=ubuntu --recheck —no-floppy

4.5 Unmount the first partition

# umount /boot/efi

4.6 Mount the second disk

# mount /dev/disk/by-id/scsi-SATA_disk2-part3 /boot/efi

4.7 Install grub

# grub-install --target=x86_64-efi --efi-directory=/boot/efi \
      --bootloader-id=ubuntu-2 --recheck —no-floppy

4.8 Repeat steps 4.5 to 4.7 for each additional disk 4.9 For added insurance, do an MBR installation to each disk too

# grub-install /dev/disk/by-id/scsi-SATA_disk1
# grub-install /dev/disk/by-id/scsi-SATA_disk2

Step 5: Reboot

5.1 Quit from the chroot

# exit

5.2 Reboot

# reboot

The easiest and best way of re-initializing grub is a utility called boot repair. Follow these steps:

1. Boot from live Ubuntu disk and select "try without installing"

2. Open a terminal and run these commands:

   sudo -i
   add-apt-repository ppa:yannubuntu/boot-repair
   apt update
   apt install boot-repair
   boot-repair

3. Chose recommended repair

4. You will eventually be presented with code to paste in the terminal. This will happen twice. Open new terminal window to do this.
5. After the program finishes restart, removing installation disk.

Boot-repair will completely re-initialize your grub and works well with UEFI.