Ubuntu 1804 ZFS root install hack

Ubuntu1804onZFS.sh

#!/bin/bash

# Starting from the work detailed on
# https://github.com/zfsonlinux/zfs/wiki/Ubuntu-18.04-Root-on-ZFS

ROOTPASSWD='ch4ng3m3P13453'

if [ -z "$HOSTNAME" ]
then
  echo env HOSTNAME must be set >&2
  exit 1
fi

SD=/dev/sda
POOL="$HOSTNAME"
BPOOL=$POOL-boot

# search for raw disk link for ZFS pool
for DISK in $( find /dev/disk/by-id -type l )
do
  if [ "$( stat -L --format='%t:%T' $DISK )" == "$( stat --format='%t:%T' $SD )" ]
  then
    break
  fi
  unset DISK
done

apt update

apt install -y zfsutils debootstrap

sgdisk --zap-all $DISK
sgdisk     -n2:1M:+512M   -t2:EF00 $DISK
sgdisk     -n3:0:+512M    -t3:BF01 $DISK
sgdisk     -n4:0:0        -t4:BF01 $DISK

# links do not appear immediately
udevadm settle --exit-if-exists=$DISK-part4
until [ "$( stat -L --printf=%F $DISK-part4 )" == "block special file" ]
do
  sleep 0.25
done

zpool create -o ashift=12 \
      -O acltype=posixacl -O canmount=off -O compression=lz4 \
      -O dnodesize=auto -O normalization=formD -O relatime=on -O xattr=sa \
      -O mountpoint=/ -R /mnt \
      $POOL $DISK-part4
      # links do not appear immediately

udevadm settle --exit-if-exists=$DISK-part3
until [ "$( stat -L --printf=%F $DISK-part3 )" == "block special file" ]
do
  sleep 0.25
done

zpool create -o ashift=12 -d \
      -o feature@async_destroy=enabled \
      -o feature@bookmarks=enabled \
      -o feature@embedded_data=enabled \
      -o feature@empty_bpobj=enabled \
      -o feature@enabled_txg=enabled \
      -o feature@extensible_dataset=enabled \
      -o feature@filesystem_limits=enabled \
      -o feature@hole_birth=enabled \
      -o feature@large_blocks=enabled \
      -o feature@lz4_compress=enabled \
      -o feature@spacemap_histogram=enabled \
      -o feature@userobj_accounting=enabled \
      -O acltype=posixacl -O canmount=off -O compression=lz4 -O devices=off \
      -O normalization=formD -O relatime=on -O xattr=sa \
      -O mountpoint=/ -R /mnt \
      $BPOOL $DISK-part3

zfs create -o canmount=off -o mountpoint=none $POOL/ROOT
zfs create -o canmount=off -o mountpoint=none $BPOOL/BOOT

zfs create -o mountpoint=/ $POOL/ROOT/ubuntu

zfs create -o mountpoint=/boot $BPOOL/BOOT/ubuntu
zfs mount $BPOOL/BOOT/ubuntu
zpool set bootfs=$BPOOL/BOOT/ubuntu $BPOOL
mkdir --mode=755 /mnt/boot/efi

zfs create                                 $POOL/home
zfs create -o mountpoint=/root             $POOL/home/root
zfs create -o canmount=off                 $POOL/var
zfs create -o canmount=off                 $POOL/var/lib
zfs create                                 $POOL/var/log
zfs create                                 $POOL/var/spool

zfs create -o com.sun:auto-snapshot=false  $POOL/var/cache
zfs create -o com.sun:auto-snapshot=false  $POOL/var/tmp
chmod 1777 /mnt/var/tmp
zfs create -o com.sun:auto-snapshot=false  $POOL/tmp
chmod 1777 /mnt/tmp

zpool get bootfs $BPOOL
echo ========
df -h
echo ========

for etcdir in /mnt/etc /mnt/etc/netplan /mnt/etc/apt
do
  [ -d $etcdir ] || mkdir --mode=775 $etcdir
done

echo "$HOSTNAME" > /mnt/etc/hostname
cat > /etc/hosts << END_ETC_HOSTS
127.0.0.1 "$HOSTNAME"
::1 "$HOSTNAME"
END_ETC_HOSTS

cat > /mnt/etc/netplan/01-netcfg.yaml << END_NETCFG
network:
  version: 2
  ethernets:
    $( ip addr|grep UP|grep -v lo:|tr -d :|cut -d' ' -f2|head -1 ):
      dhcp4: true
      dhcp6: true
END_NETCFG

cat >> /mnt/etc/apt/sources.list < /etc/apt/sources.list

LANG=C TZ='US/Central' debootstrap bionic /mnt
zfs set devices=off $POOL

for mp in dev proc sys
do
  [ -d /mnt/$mp ] || mkdir --mode=775 /mnt/$mp
done

mount --rbind /dev  /mnt/dev
mount --rbind /proc /mnt/proc
mount --rbind /sys  /mnt/sys

chroot /mnt /bin/bash -x << END_CHROOTSCRIPT
export ZPOOL_VDEV_NAME_PATH=YES
ln -s /proc/self/mounts /etc/mtab
apt update

locale-gen --purge en_US.UTF-8 && \
echo -e 'LANG="en_US.UTF-8"\nLANGUAGE="en_US:en"\n' > /etc/default/locale

ln -fs /usr/share/zoneinfo/America/Chicago /etc/localtime
dpkg-reconfigure -f noninteractive tzdata

apt install --yes dosfstools

mkdosfs -F 32 -s 1 -n EFI $DISK-part2
[ -d /boot/efi ] && rm -rf /boot/efi/* || mkdir /boot/efi
echo PARTUUID=$(blkid -s PARTUUID -o value \
      $DISK-part2) \
      /boot/efi vfat nofail,x-systemd.device-timeout=1 0 1 >> /etc/fstab
[ -d /boot/efi ] || mkdir --mode 755 /boot/efi
mount /boot/efi

echo ========
df -h
echo ========

apt install --yes --no-install-recommends linux-image-generic
apt install --yes zfsutils

apt install --yes grub-efi-amd64-signed shim-signed

echo root:"$ROOTPASSWD" | chpasswd

update-initramfs -u -k all
echo 'GRUB_CMDLINE_LINUX="root=ZFS=$POOL/ROOT/ubuntu"' >> /etc/default/grub

update-grub && echo update-grub #OK

grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=ubuntu --recheck --no-floppy --no-rs-codes &&
  echo grub-install #OK

find /boot/grub

for try in {1..10}
do
  umount /boot/efi && break
  echo waiting $try
  sleep 0.5
done

END_CHROOTSCRIPT

# disable logrotate compression on compressed zfs log fs
find /mnt/etc/logrotate.d/* -prune| ( while read file;
do
    if grep -Eq "(^|[^#y])compress" "$file" ;
    then
        sed -i -r "s/(^|[^#y])(compress)/\1#\2/" "$file"
    fi
done )

zfs unmount $BPOOL/BOOT/ubuntu
zfs set mountpoint=legacy $BPOOL/BOOT/ubuntu
sync;sleep 0.25;sync;sleep 0.25;sync;sleep 0.25

echo $BPOOL/BOOT/ubuntu /boot zfs \
      nodev,relatime,x-systemd.requires=zfs-import-bpool.service 0 0 >> /mnt/etc/fstab
zfs set mountpoint=legacy $POOL/var/log
echo $POOL/var/log /var/log zfs nodev,relatime 0 0 >> /mnt/etc/fstab
zfs set mountpoint=legacy $POOL/var/spool
echo $POOL/var/spool /var/spool zfs nodev,relatime 0 0 >> /mnt/etc/fstab
zfs set mountpoint=legacy $POOL/var/tmp
echo $POOL/var/tmp /var/tmp zfs nodev,relatime 0 0 >> /mnt/etc/fstab
zfs set mountpoint=legacy $POOL/tmp
echo $POOL/tmp /tmp zfs nodev,relatime 0 0 >> /mnt/etc/fstab

mount | grep -v zfs | tac | awk '/\/mnt/ {print $3}' | xargs -i{} umount -lf {}

zfs snapshot $BPOOL/BOOT/ubuntu@preboot
zfs snapshot $POOL/ROOT/ubuntu@install

sync;sleep 0.25;sync;sleep 0.25;sync;sleep 0.25
zpool export -a