removed double quoting from zpool statements

remove zfs-boot helper service, obsolete in OpenZFS 2.0

.github/workflows/shellcheck.yml

@@ -0,0 +1,11 @@
+name: shellcheck
+
+on: push
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Run shellcheck
+      run: ci/run_shellcheck.sh

README.md

@@ -1,6 +1,8 @@
 # zfs-hetzner-vm
 
-Scripts to install Debian 10 or Ubuntu 18 with ZFS root on Hetzner root servers (virtual and dedicated).<br/>
+[![shellcheck](https://github.com/terem42/zfs-hetzner-vm/actions/workflows/shellcheck.yml/badge.svg)](https://github.com/terem42/zfs-hetzner-vm/actions/workflows/shellcheck.yml)
+
+Scripts to install Debian 11, 10 or Ubuntu 20, 18 with ZFS root on Hetzner root servers (virtual and dedicated).<br/>
 __WARNING:__ all data on the disk will be destroyed.
 
 ## How to use:
@@ -10,23 +12,36 @@ __WARNING:__ all data on the disk will be destroyed.
 * Click "enable rescue and power cycle",  add SSH key to the rescue console, set it OS to linux64, then press mount rescue and power cycle" button.
 * connect via SSH to rescue console, and run the script from this repo.
 
+Debian 11 minimal setup with SSH server
+
+````bash
+wget -qO- https://raw.githubusercontent.com/terem42/zfs-hetzner-vm/master/hetzner-debian11-zfs-setup.sh | bash -
+````
+
+Ubuntu 20 LTS minimal setup with SSH server
+
+````bash
+wget -qO- https://raw.githubusercontent.com/terem42/zfs-hetzner-vm/master/hetzner-ubuntu20-zfs-setup.sh | bash -
+````
+
 Debian 10 minimal setup with SSH server
 
-````
+````bash
-wget -qO- https://raw.githubusercontent.com/andrey42/zfs-hetzner-vm/master/hetzner-debian10-zfs-setup.sh | bash -
+wget -qO- https://raw.githubusercontent.com/terem42/zfs-hetzner-vm/master/hetzner-debian10-zfs-setup.sh | bash -
 ````
 
 Ubuntu 18.04 LTS minimal setup with SSH server
 
-````
+````bash
-wget -qO- https://raw.githubusercontent.com/andrey42/zfs-hetzner-vm/master/hetzner-ubuntu18-zfs-setup.sh | bash -
+wget -qO- https://raw.githubusercontent.com/terem42/zfs-hetzner-vm/master/hetzner-ubuntu18-zfs-setup.sh | bash -
 ````
 
 Answer script questions about desired hostname and ZFS ARC cache size.
 
 To cope with network failures its higly recommended to run the commands above inside screen console, type `man screen` for more info.
 Example of screen utility usage:
-````
+
+````bash
 screen -S zfs
 ````
 To detach from screen console, hit Ctrl-d then a

ci/run_shellcheck.sh

@@ -0,0 +1,25 @@
+#!/bin/bash
+
+set -o pipefail
+set -o errexit
+set -o nounset
+set -o errtrace
+shopt -s inherit_errexit
+
+# Always download the latest version:
+#
+# - it's fast and stable enough not to worry about it;
+# - the workflow is basically single-person, so there's no risk of a new dev encountering an error found
+#   by a new shellcheck version.
+
+mkdir -p /opt/shellcheck
+
+wget -qO- https://github.com/koalaman/shellcheck/releases/download/stable/shellcheck-stable.linux.x86_64.tar.xz \
+  | tar xJv -O shellcheck-stable/shellcheck \
+  > /opt/shellcheck/shellcheck
+
+chmod +x /opt/shellcheck/shellcheck
+
+/opt/shellcheck/shellcheck --version
+
+grep -lZP '^#!/bin/\w+sh' -R | xargs -0 /opt/shellcheck/shellcheck

hetzner-debian10-zfs-setup.sh

@@ -40,7 +40,7 @@ c_deb_security_repo=http://mirror.hetzner.de/debian/security
 
 c_default_zfs_arc_max_mb=250
 c_default_bpool_tweaks="-o ashift=12 -O compression=lz4"
-c_default_rpool_tweaks="-o ashift=12 -O acltype=posixacl -O compression=lz4 -O dnodesize=auto -O relatime=on -O xattr=sa -O normalization=formD"
+c_default_rpool_tweaks="-o ashift=12 -O acltype=posixacl -O compression=zstd-9 -O dnodesize=auto -O relatime=on -O xattr=sa -O normalization=formD"
 c_default_hostname=terem
 c_zfs_mount_dir=/mnt
 c_log_dir=$(dirname "$(mktemp)")/zfs-hetzner-vm
@@ -62,7 +62,9 @@ function print_step_info_header {
 ###############################################################################
 # ${FUNCNAME[1]}"
 
-  [[ "${1:-}" != "" ]] && echo -n " $1" || true
+  if [[ "${1:-}" != "" ]]; then
+    echo -n " $1" 
+  fi
 
   echo "
 ###############################################################################
@@ -106,7 +108,7 @@ This script will prepare the ZFS pools, then install and configure minimal Debia
 The script with minimal changes may be used on any other hosting provider  supporting KVM virtualization and offering Debian-based rescue system.
 In order to stop the procedure, hit Esc twice during dialogs (excluding yes/no ones), or Ctrl+C while any operation is running.
 '
-  dialog --ascii-lines --msgbox "$dialog_message" 30 100
+  dialog --msgbox "$dialog_message" 30 100
 }
 
 function store_os_distro_information {
@@ -135,19 +137,19 @@ function check_prerequisites {
 function initial_load_debian_zed_cache {
   chroot_execute "mkdir /etc/zfs/zfs-list.cache"
   chroot_execute "touch /etc/zfs/zfs-list.cache/rpool"
-  chroot_execute "ln -s /usr/lib/zfs-linux/zed.d/history_event-zfs-list-cacher.sh /etc/zfs/zed.d/"
+  chroot_execute "ln -sf /usr/lib/zfs-linux/zed.d/history_event-zfs-list-cacher.sh /etc/zfs/zed.d/"
 
   chroot_execute "zed -F &"
 
   local success=0
 
-  if [[ ! -e /mnt/etc/zfs/zfs-list.cache/rpool ]] || [[ -e /mnt/etc/zfs/zfs-list.cache/rpool && (( $(ls -l /mnt/etc/zfs/zfs-list.cache/rpool 2> /dev/null | cut -d ' ' -f 5) == 0 )) ]]; then
+  if [[ ! -e /mnt/etc/zfs/zfs-list.cache/rpool ]] || [[ -e /mnt/etc/zfs/zfs-list.cache/rpool && (( $(find /mnt/etc/zfs/zfs-list.cache/rpool -type f -printf '%s' 2> /dev/null) == 0 )) ]]; then
     chroot_execute "zfs set canmount=noauto rpool"
 
     SECONDS=0
 
     while (( SECONDS++ <= 120 )); do
-      if [[ -e /mnt/etc/zfs/zfs-list.cache/rpool ]] && (( "$(ls -l /mnt/etc/zfs/zfs-list.cache/rpool | cut -d ' ' -f 5)" > 0 )); then
+      if [[ -e /mnt/etc/zfs/zfs-list.cache/rpool ]] && (( $(find /mnt/etc/zfs/zfs-list.cache/rpool -type f -printf '%s' 2> /dev/null) > 0 )); then
         success=1
         break
       else
@@ -208,9 +210,9 @@ LOG
   if [[ ${#v_suitable_disks[@]} -eq 0 ]]; then
     local dialog_message='No suitable disks have been found!
 
-If you think this is a bug, please open an issue on https://github.com/andrey42/zfs-hetzner-vm/issues, and attach the file `'"$c_disks_log"'`.
+If you think this is a bug, please open an issue on https://github.com/terem42/zfs-hetzner-vm/issues, and attach the file `'"$c_disks_log"'`.
 '
-    dialog --ascii-lines --msgbox "$dialog_message" 30 100
+    dialog --msgbox "$dialog_message" 30 100
 
     exit 1
   fi
@@ -239,7 +241,7 @@ function select_disks {
 
 Devices with mounted partitions, cdroms, and removable devices are not displayed!
 "
-    mapfile -t v_selected_disks < <(dialog --ascii-lines --separate-output --checklist "$dialog_message" 30 100 $((${#menu_entries_option[@]} / 3)) "${menu_entries_option[@]}" 3>&1 1>&2 2>&3)
+    mapfile -t v_selected_disks < <(dialog --separate-output --checklist "$dialog_message" 30 100 $((${#menu_entries_option[@]} / 3)) "${menu_entries_option[@]}" 3>&1 1>&2 2>&3)
 
     if [[ ${#v_selected_disks[@]} -gt 0 ]]; then
       break
@@ -256,7 +258,7 @@ function ask_swap_size {
   local swap_size_invalid_message=
 
   while [[ ! $v_swap_size =~ ^[0-9]+$ ]]; do
-    v_swap_size=$(dialog --ascii-lines --inputbox "${swap_size_invalid_message}Enter the swap size in GiB (0 for no swap):" 30 100 2 3>&1 1>&2 2>&3)
+    v_swap_size=$(dialog --inputbox "${swap_size_invalid_message}Enter the swap size in GiB (0 for no swap):" 30 100 2 3>&1 1>&2 2>&3)
 
     swap_size_invalid_message="Invalid swap size! "
   done
@@ -271,7 +273,7 @@ function ask_free_tail_space {
   local tail_space_invalid_message=
 
   while [[ ! $v_free_tail_space =~ ^[0-9]+$ ]]; do
-    v_free_tail_space=$(dialog --ascii-lines --inputbox "${tail_space_invalid_message}Enter the space to leave at the end of each disk (0 for none):" 30 100 0 3>&1 1>&2 2>&3)
+    v_free_tail_space=$(dialog --inputbox "${tail_space_invalid_message}Enter the space to leave at the end of each disk (0 for none):" 30 100 0 3>&1 1>&2 2>&3)
 
     tail_space_invalid_message="Invalid size! "
   done
@@ -286,7 +288,7 @@ function ask_zfs_arc_max_size {
   local zfs_arc_max_invalid_message=
 
   while [[ ! $v_zfs_arc_max_mb =~ ^[0-9]+$ ]]; do
-    v_zfs_arc_max_mb=$(dialog --ascii-lines --inputbox "${zfs_arc_max_invalid_message}Enter ZFS ARC cache max size in Mb (minimum 64Mb, enter 0 for ZFS default value, the default will take up to 50% of memory):" 30 100 "$c_default_zfs_arc_max_mb" 3>&1 1>&2 2>&3)
+    v_zfs_arc_max_mb=$(dialog --inputbox "${zfs_arc_max_invalid_message}Enter ZFS ARC cache max size in Mb (minimum 64Mb, enter 0 for ZFS default value, the default will take up to 50% of memory):" 30 100 "$c_default_zfs_arc_max_mb" 3>&1 1>&2 2>&3)
 
     zfs_arc_max_invalid_message="Invalid size! "
   done
@@ -302,14 +304,14 @@ function ask_pool_names {
   local bpool_name_invalid_message=
 
   while [[ ! $v_bpool_name =~ ^[a-z][a-zA-Z_:.-]+$ ]]; do
-    v_bpool_name=$(dialog --ascii-lines --inputbox "${bpool_name_invalid_message}Insert the name for the boot pool" 30 100 bpool 3>&1 1>&2 2>&3)
+    v_bpool_name=$(dialog --inputbox "${bpool_name_invalid_message}Insert the name for the boot pool" 30 100 bpool 3>&1 1>&2 2>&3)
 
     bpool_name_invalid_message="Invalid pool name! "
   done
   local rpool_name_invalid_message=
 
   while [[ ! $v_rpool_name =~ ^[a-z][a-zA-Z_:.-]+$ ]]; do
-    v_rpool_name=$(dialog --ascii-lines --inputbox "${rpool_name_invalid_message}Insert the name for the root pool" 30 100 rpool 3>&1 1>&2 2>&3)
+    v_rpool_name=$(dialog --inputbox "${rpool_name_invalid_message}Insert the name for the root pool" 30 100 rpool 3>&1 1>&2 2>&3)
 
     rpool_name_invalid_message="Invalid pool name! "
   done
@@ -321,8 +323,8 @@ function ask_pool_tweaks {
   # shellcheck disable=SC2119
   print_step_info_header
 
-  v_bpool_tweaks=$(dialog --ascii-lines --inputbox "Insert the tweaks for the boot pool" 30 100 -- "$c_default_bpool_tweaks" 3>&1 1>&2 2>&3)
+  v_bpool_tweaks=$(dialog --inputbox "Insert the tweaks for the boot pool" 30 100 -- "$c_default_bpool_tweaks" 3>&1 1>&2 2>&3)
-  v_rpool_tweaks=$(dialog --ascii-lines --inputbox "Insert the tweaks for the root pool" 30 100 -- "$c_default_rpool_tweaks" 3>&1 1>&2 2>&3)
+  v_rpool_tweaks=$(dialog --inputbox "Insert the tweaks for the root pool" 30 100 -- "$c_default_rpool_tweaks" 3>&1 1>&2 2>&3)
 
   print_variables v_bpool_tweaks v_rpool_tweaks
 }
@@ -337,8 +339,8 @@ function ask_root_password {
   local password_repeat=-
 
   while [[ "$v_root_password" != "$password_repeat" || "$v_root_password" == "" ]]; do
-    v_root_password=$(dialog --ascii-lines --passwordbox "${password_invalid_message}Please enter the root account password (can't be empty):" 30 100 3>&1 1>&2 2>&3)
+    v_root_password=$(dialog --passwordbox "${password_invalid_message}Please enter the root account password (can't be empty):" 30 100 3>&1 1>&2 2>&3)
-    password_repeat=$(dialog --ascii-lines --passwordbox "Please repeat the password:" 30 100 3>&1 1>&2 2>&3)
+    password_repeat=$(dialog --passwordbox "Please repeat the password:" 30 100 3>&1 1>&2 2>&3)
 
     password_invalid_message="Passphrase empty, or not matching! "
   done
@@ -348,7 +350,7 @@ function ask_root_password {
 function ask_encryption {
   print_step_info_header
 
-  if dialog --ascii-lines --yesno 'Do you want to encrypt the root pool?' 30 100; then
+  if dialog --defaultno --yesno 'Do you want to encrypt the root pool?' 30 100; then
     v_encrypt_rpool=1
   fi
   set +x
@@ -356,8 +358,8 @@ function ask_encryption {
     local passphrase_invalid_message=
     local passphrase_repeat=-
     while [[ "$v_passphrase" != "$passphrase_repeat" || ${#v_passphrase} -lt 8 ]]; do
-      v_passphrase=$(dialog --ascii-lines --passwordbox "${passphrase_invalid_message}Please enter the passphrase for the root pool (8 chars min.):" 30 100 3>&1 1>&2 2>&3)
+      v_passphrase=$(dialog --passwordbox "${passphrase_invalid_message}Please enter the passphrase for the root pool (8 chars min.):" 30 100 3>&1 1>&2 2>&3)
-      passphrase_repeat=$(dialog --ascii-lines --passwordbox "Please repeat the passphrase:" 30 100 3>&1 1>&2 2>&3)
+      passphrase_repeat=$(dialog --passwordbox "Please repeat the passphrase:" 30 100 3>&1 1>&2 2>&3)
 
       passphrase_invalid_message="Passphrase too short, or not matching! "
     done
@@ -368,7 +370,7 @@ function ask_encryption {
 function ask_zfs_experimental {
   print_step_info_header
 
-  if dialog --ascii-lines --yesno 'Do you want to use experimental zfs module build?' 30 100; then
+  if dialog --defaultno --yesno 'Do you want to use experimental zfs module build?' 30 100; then
     v_zfs_experimental=1
   fi
 }
@@ -380,7 +382,7 @@ function ask_hostname {
   local hostname_invalid_message=
 
   while [[ ! $v_hostname =~ ^[a-z][a-zA-Z_:.-]+$ ]]; do
-    v_hostname=$(dialog --ascii-lines --inputbox "${hostname_invalid_message}Set the host name" 30 100 "$c_default_hostname" 3>&1 1>&2 2>&3)
+    v_hostname=$(dialog --inputbox "${hostname_invalid_message}Set the host name" 30 100 "$c_default_hostname" 3>&1 1>&2 2>&3)
 
     hostname_invalid_message="Invalid host name! "
   done
@@ -431,9 +433,8 @@ function unmount_and_export_fs {
   zpools_exported=99
   echo "===========exporting zfs pools============="
   set +e
-  while (( zpools_exported == 99 )) && (( SECONDS++ <= 60 )); do
+  while (( zpools_exported == 99 )) && (( SECONDS++ <= 60 )); do    
-    zpool export -a 2> /dev/null
+    if zpool export -a 2> /dev/null; then
-    if [[ $? == 0 ]]; then
       zpools_exported=1
       echo "all zfs pools were succesfully exported"
       break;
@@ -450,6 +451,7 @@ function unmount_and_export_fs {
 
 #################### MAIN ################################
 export LC_ALL=en_US.UTF-8
+export NCURSES_NO_UTF8_ACS=1
 
 check_prerequisites
 
@@ -491,10 +493,14 @@ done
 
 echo "======= installing zfs on rescue system =========="
   echo "zfs-dkms zfs-dkms/note-incompatible-licenses note true" | debconf-set-selections
-
+  apt-get install --yes software-properties-common
+  apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 8CF63AD3F06FC659
+  add-apt-repository 'deb http://ppa.launchpad.net/jonathonf/zfs/ubuntu focal main'
   apt update
-  apt install --yes -t buster-backports libelf-dev zfs-dkms
+  apt install --yes zfs-dkms zfsutils-linux
-  modprobe zfs
+  add-apt-repository -r 'deb http://ppa.launchpad.net/jonathonf/zfs/ubuntu focal main'
+  apt update
+  find /usr/local/sbin/ -type l -exec rm {} +
   zfs --version
 
 echo "======= partitioning the disk =========="
@@ -506,7 +512,7 @@ echo "======= partitioning the disk =========="
   fi
 
   for selected_disk in "${v_selected_disks[@]}"; do
-    wipefs --all "$selected_disk"
+    wipefs --all --force "$selected_disk"
     sgdisk -a1 -n1:24K:+1000K            -t1:EF02 "$selected_disk"
     sgdisk -n2:0:+512M                   -t2:BF01 "$selected_disk" # Boot pool
     sgdisk -n3:0:"$tail_space_parameter" -t3:BF01 "$selected_disk" # Root pool
@@ -535,12 +541,16 @@ echo "======= create zfs pools and datasets =========="
     pools_mirror_option=
   fi
 
+# shellcheck disable=SC2086
 zpool create \
-  $v_bpool_tweaks -O canmount=off -O devices=off \
+  "$v_bpool_tweaks" -O canmount=off -O devices=off \
+  -o cachefile=/etc/zfs/zpool.cache \
   -O mountpoint=/boot -R $c_zfs_mount_dir -f \
   $v_bpool_name $pools_mirror_option "${bpool_disks_partitions[@]}"
 
+# shellcheck disable=SC2086
 echo -n "$v_passphrase" | zpool create \
+  -o cachefile=/etc/zfs/zpool.cache \
   $v_rpool_tweaks \
   "${encryption_options[@]}" \
   -O mountpoint=/ -R $c_zfs_mount_dir -f \
@@ -552,8 +562,8 @@ zfs create -o canmount=off -o mountpoint=none "$v_bpool_name/BOOT"
 zfs create -o canmount=noauto -o mountpoint=/ "$v_rpool_name/ROOT/debian"
 zfs mount "$v_rpool_name/ROOT/debian"
 
-zfs create -o canmount=noauto -o mountpoint=/boot "$v_bpool_name/BOOT/ubuntu"
+zfs create -o canmount=noauto -o mountpoint=/boot "$v_bpool_name/BOOT/debian"
-zfs mount "$v_bpool_name/BOOT/ubuntu"
+zfs mount "$v_bpool_name/BOOT/debian"
 
 zfs create                                 "$v_rpool_name/home"
 zfs create -o mountpoint=/root             "$v_rpool_name/home/root"
@@ -698,20 +708,17 @@ echo "======= installing aux packages =========="
 chroot_execute "apt install --yes man wget curl software-properties-common nano htop gnupg"
 
 echo "======= installing zfs packages =========="
-if [[ $v_zfs_experimental == "1" ]]; then
-  chroot_execute "wget -O - https://andrey42.github.io/zfs-ubuntu/apt_pub.gpg | apt-key add -"
-  chroot_execute "add-apt-repository 'deb https://andrey42.github.io/zfs-ubuntu/public zfs-debian-experimental main'"
-  chroot_execute "apt update"
-else
-  chroot_execute "apt install --yes zfs-initramfs zfs-dkms"
-fi
 chroot_execute 'echo "zfs-dkms zfs-dkms/note-incompatible-licenses note true" | debconf-set-selections'
 
 if [[ $v_zfs_experimental == "1" ]]; then
-  chroot_execute "apt install --yes zfs-initramfs zfs-dkms zfsutils-linux"
+  chroot_execute "wget -O - https://terem42.github.io/zfs-debian/apt_pub.gpg | apt-key add -"
-else
+  chroot_execute "add-apt-repository 'deb https://terem42.github.io/zfs-debian/public zfs-debian-experimental main'"
+  chroot_execute "apt update"
   chroot_execute "apt install -t zfs-debian-experimental --yes zfs-initramfs zfs-dkms zfsutils-linux"
+else
+  chroot_execute "apt install --yes -t buster-backports zfs-initramfs zfs-dkms zfsutils-linux"
 fi
+
 echo "======= installing OpenSSH and network tooling =========="
 chroot_execute "apt install --yes openssh-server net-tools"
 
@@ -726,25 +733,8 @@ chroot_execute "dpkg-reconfigure openssh-server -f noninteractive"
 echo "======= set root password =========="
 chroot_execute "echo root:$(printf "%q" "$v_root_password") | chpasswd"
 
-echo "======= setting up zfs services =========="
+echo "======= setting up zfs cache =========="
-chroot_execute "cat > /etc/systemd/system/zfs-import-bpool.service <<UNIT
+cp /etc/zfs/zpool.cache /mnt/etc/zfs/zpool.cache
-[Unit]
-DefaultDependencies=no
-Before=zfs-import-scan.service
-Before=zfs-import-cache.service
-
-[Service]
-Type=oneshot
-RemainAfterExit=yes
-ExecStartPre=/bin/sh -c '[ -f /etc/zfs/zpool.cache ] && mv /etc/zfs/zpool.cache /etc/zfs/preboot_zpool.cache || true'
-ExecStart=/sbin/zpool import -N -o cachefile=none $v_bpool_name
-ExecStartPost=/bin/sh -c '[ -f /etc/zfs/preboot_zpool.cache ] && mv /etc/zfs/preboot_zpool.cache /etc/zfs/zpool.cache || true'
-
-[Install]
-WantedBy=zfs-import.target
-UNIT"
-
-chroot_execute "systemctl enable zfs-import-bpool.service"
 
 echo "========setting up zfs module parameters========"
 chroot_execute "echo options zfs zfs_arc_max=$((v_zfs_arc_max_mb * 1024 * 1024)) >> /etc/modprobe.d/zfs.conf"
@@ -787,18 +777,6 @@ if [[ $v_encrypt_rpool == "1" ]]; then
   rm -rf "$c_zfs_mount_dir/etc/dropbear-initramfs/dropbear_dss_host_key"
 fi 
 
-#cd "$c_zfs_mount_dir/root"
-#wget http://ftp.de.debian.org/debian/pool/main/libt/libtommath/libtommath1_1.1.0-3_amd64.deb
-#wget http://ftp.de.debian.org/debian/pool/main/d/dropbear/dropbear-bin_2018.76-5_amd64.deb
-#wget http://ftp.de.debian.org/debian/pool/main/d/dropbear/dropbear-initramfs_2018.76-5_all.deb
-
-#chroot_execute "dpkg -i /root/libtommath1_1.1.0-3_amd64.deb"
-#chroot_execute "dpkg -i /root/dropbear-bin_2018.76-5_amd64.deb"
-#chroot_execute "dpkg -i /root/dropbear-initramfs_2018.76-5_all.deb"
-
-#rm $c_zfs_mount_dir/root/*.deb
-#cd /root
-
 echo "============setup root prompt============"
 cat > "$c_zfs_mount_dir/root/.bashrc" <<CONF
 export PS1='\[\033[01;31m\]\u\[\033[01;33m\]@\[\033[01;32m\]\h \[\033[01;33m\]\w \[\033[01;35m\]\$ \[\033[00m\]'
@@ -810,8 +788,31 @@ CONF
 echo "========running packages upgrade==========="
 chroot_execute "apt upgrade --yes"
 
-#echo "===========add static route to initramfs via hook to add default routes due to  initramfs DHCP bug ========="
+echo "===========add static route to initramfs via hook to add default routes for Hetzner due to Debian/Ubuntu initramfs DHCP bug ========="
-# removed
+mkdir -p "$c_zfs_mount_dir/usr/share/initramfs-tools/scripts/init-premount"
+cat > "$c_zfs_mount_dir/usr/share/initramfs-tools/scripts/init-premount/static-route" <<'CONF'
+#!/bin/sh
+PREREQ=""
+prereqs()
+{
+    echo "$PREREQ"
+}
+
+case $1 in
+prereqs)
+    prereqs
+    exit 0
+    ;;
+esac
+
+. /scripts/functions
+# Begin real processing below this line
+
+configure_networking
+
+ip route add 172.31.1.1/255.255.255.255 dev ens3
+ip route add default via 172.31.1.1 dev ens3
+CONF
 
 echo "======= update initramfs =========="
 chroot_execute "update-initramfs -u -k all"
@@ -827,8 +828,8 @@ else
 fi
 
 echo "======= setting mountpoints =========="
-chroot_execute "zfs set mountpoint=legacy $v_bpool_name/BOOT/ubuntu"
+chroot_execute "zfs set mountpoint=legacy $v_bpool_name/BOOT/debian"
-chroot_execute "echo $v_bpool_name/BOOT/ubuntu /boot zfs nodev,relatime,x-systemd.requires=zfs-import-bpool.service 0 0 > /etc/fstab"
+chroot_execute "echo $v_bpool_name/BOOT/debian /boot zfs nodev,relatime,x-systemd.requires=zfs-mount.service,x-systemd.device-timeout=10 0 0 > /etc/fstab"
 
 chroot_execute "zfs set mountpoint=legacy $v_rpool_name/var/log"
 chroot_execute "echo $v_rpool_name/var/log /var/log zfs nodev,relatime 0 0 >> /etc/fstab"
@@ -840,7 +841,9 @@ chroot_execute "zfs set mountpoint=legacy $v_rpool_name/tmp"
 chroot_execute "echo $v_rpool_name/tmp /tmp zfs nodev,relatime 0 0 >> /etc/fstab"
 
 echo "========= add swap, if defined"
-[[ $v_swap_size -gt 0 ]] && chroot_execute "echo /dev/zvol/$v_rpool_name/swap none swap discard 0 0 >> /etc/fstab" || true
+if [[ $v_swap_size -gt 0 ]]; then
+  chroot_execute "echo /dev/zvol/$v_rpool_name/swap none swap discard 0 0 >> /etc/fstab"
+fi
 chroot_execute "echo RESUME=none > /etc/initramfs-tools/conf.d/resume"
 
 echo "======= unmounting filesystems and zfs pools =========="

hetzner-debian11-zfs-setup.sh

@@ -0,0 +1,859 @@
+#!/bin/bash
+
+: <<'end_header_info'
+(c) Andrey Prokopenko job@terem.fr
+fully automatic script to install Debian 11 with ZFS root on Hetzner VPS
+WARNING: all data on the disk will be destroyed
+How to use: add SSH key to the rescue console, set it OS to linux64, then press "mount rescue and power cycle" button
+Next, connect via SSH to console, and run the script
+Answer script questions about desired hostname, ZFS ARC cache size et cetera
+To cope with network failures its higly recommended to run the script inside screen console
+screen -dmS zfs
+screen -r zfs
+To detach from screen console, hit Ctrl-d then a
+end_header_info
+
+set -o errexit
+set -o pipefail
+set -o nounset
+
+# Variables
+v_bpool_name=
+v_bpool_tweaks=
+v_rpool_name=
+v_rpool_tweaks=
+declare -a v_selected_disks
+v_swap_size=                 # integer
+v_free_tail_space=           # integer
+v_hostname=
+v_kernel_variant=
+v_zfs_arc_max_mb=
+v_root_password=
+v_encrypt_rpool=             # 0=false, 1=true
+v_passphrase=
+v_zfs_experimental=
+v_suitable_disks=()
+
+# Constants
+c_deb_packages_repo=https://mirror.hetzner.com/debian/packages
+c_deb_security_repo=https://mirror.hetzner.com/debian/security
+
+c_default_zfs_arc_max_mb=250
+c_default_bpool_tweaks="-o ashift=12 -O compression=lz4"
+c_default_rpool_tweaks="-o ashift=12 -O acltype=posixacl -O compression=zstd-9 -O dnodesize=auto -O relatime=on -O xattr=sa -O normalization=formD"
+c_default_hostname=terem
+c_zfs_mount_dir=/mnt
+c_log_dir=$(dirname "$(mktemp)")/zfs-hetzner-vm
+c_install_log=$c_log_dir/install.log
+c_lsb_release_log=$c_log_dir/lsb_release.log
+c_disks_log=$c_log_dir/disks.log
+
+function activate_debug {
+  mkdir -p "$c_log_dir"
+
+  exec 5> "$c_install_log"
+  BASH_XTRACEFD="5"
+  set -x
+}
+
+# shellcheck disable=SC2120
+function print_step_info_header {
+  echo -n "
+###############################################################################
+# ${FUNCNAME[1]}"
+
+  if [[ "${1:-}" != "" ]]; then
+    echo -n " $1" 
+  fi
+
+
+  echo "
+###############################################################################
+"
+}
+
+function print_variables {
+  for variable_name in "$@"; do
+    declare -n variable_reference="$variable_name"
+
+    echo -n "$variable_name:"
+
+    case "$(declare -p "$variable_name")" in
+    "declare -a"* )
+      for entry in "${variable_reference[@]}"; do
+        echo -n " \"$entry\""
+      done
+      ;;
+    "declare -A"* )
+      for key in "${!variable_reference[@]}"; do
+        echo -n " $key=\"${variable_reference[$key]}\""
+      done
+      ;;
+    * )
+      echo -n " $variable_reference"
+      ;;
+    esac
+
+    echo
+  done
+
+  echo
+}
+
+function display_intro_banner {
+  # shellcheck disable=SC2119
+  print_step_info_header
+
+  local dialog_message='Hello!
+This script will prepare the ZFS pools, then install and configure minimal Debian 11 with ZFS root on Hetzner hosting VPS instance
+The script with minimal changes may be used on any other hosting provider  supporting KVM virtualization and offering Debian-based rescue system.
+In order to stop the procedure, hit Esc twice during dialogs (excluding yes/no ones), or Ctrl+C while any operation is running.
+'
+  dialog --msgbox "$dialog_message" 30 100
+}
+
+function store_os_distro_information {
+  # shellcheck disable=SC2119
+  print_step_info_header
+
+  lsb_release --all > "$c_lsb_release_log"
+}
+
+function check_prerequisites {
+  # shellcheck disable=SC2119
+  print_step_info_header
+  if [[ $(id -u) -ne 0 ]]; then
+    echo 'This script must be run with administrative privileges!'
+    exit 1
+  fi
+  if [[ ! -r /root/.ssh/authorized_keys ]]; then
+    echo "SSH pubkey file is absent, please add it to the rescue system setting, then reboot into rescue system and run the script"
+    exit 1
+  fi
+  if ! dpkg-query --showformat="\${Status}" -W dialog 2> /dev/null | grep -q "install ok installed"; then
+    apt install --yes dialog
+  fi
+}
+
+function initial_load_debian_zed_cache {
+  chroot_execute "mkdir /etc/zfs/zfs-list.cache"
+  chroot_execute "touch /etc/zfs/zfs-list.cache/rpool"
+  chroot_execute "ln -sf /usr/lib/zfs-linux/zed.d/history_event-zfs-list-cacher.sh /etc/zfs/zed.d/"
+
+  chroot_execute "zed -F &"
+
+  local success=0
+
+  if [[ ! -e /mnt/etc/zfs/zfs-list.cache/rpool ]] || [[ -e /mnt/etc/zfs/zfs-list.cache/rpool && (( $(find /mnt/etc/zfs/zfs-list.cache/rpool -type f -printf '%s' 2> /dev/null) == 0 )) ]]; then  
+    chroot_execute "zfs set canmount=noauto rpool"
+
+    SECONDS=0
+
+    while (( SECONDS++ <= 120 )); do
+      if [[ -e /mnt/etc/zfs/zfs-list.cache/rpool ]] && (( $(find /mnt/etc/zfs/zfs-list.cache/rpool -type f -printf '%s' 2> /dev/null) > 0 )); then
+        success=1
+        break
+      else
+        sleep 1
+      fi
+    done
+  else
+    success=1
+  fi
+
+  if (( success != 1 )); then
+    echo "Fatal zed daemon error: the ZFS cache hasn't been updated by ZED!"
+    exit 1
+  fi
+
+  chroot_execute "pkill zed"
+
+  sed -Ei 's|/mnt/?|/|g' /mnt/etc/zfs/zfs-list.cache/rpool
+}
+
+function find_suitable_disks {
+  # shellcheck disable=SC2119
+  print_step_info_header
+
+  udevadm trigger
+
+  # shellcheck disable=SC2012
+  ls -l /dev/disk/by-id | tail -n +2 | perl -lane 'print "@F[8..10]"' > "$c_disks_log"
+
+  local candidate_disk_ids
+  local mounted_devices
+
+  candidate_disk_ids=$(find /dev/disk/by-id -regextype awk -regex '.+/(ata|nvme|scsi)-.+' -not -regex '.+-part[0-9]+$' | sort)
+  mounted_devices="$(df | awk 'BEGIN {getline} {print $1}' | xargs -n 1 lsblk -no pkname 2> /dev/null | sort -u || true)"
+
+  while read -r disk_id || [[ -n "$disk_id" ]]; do
+    local device_info
+
+    device_info="$(udevadm info --query=property "$(readlink -f "$disk_id")")"
+    block_device_basename="$(basename "$(readlink -f "$disk_id")")"
+
+    if ! grep -q '^ID_TYPE=cd$' <<< "$device_info"; then
+      if ! grep -q "^$block_device_basename\$" <<< "$mounted_devices"; then
+        v_suitable_disks+=("$disk_id")
+      fi
+    fi
+
+    cat >> "$c_disks_log" << LOG
+
+## DEVICE: $disk_id ################################
+
+$(udevadm info --query=property "$(readlink -f "$disk_id")")
+
+LOG
+
+  done < <(echo -n "$candidate_disk_ids")
+
+  if [[ ${#v_suitable_disks[@]} -eq 0 ]]; then
+    local dialog_message='No suitable disks have been found!
+
+If you think this is a bug, please open an issue on https://github.com/terem42/zfs-hetzner-vm/issues, and attach the file `'"$c_disks_log"'`.
+'
+    dialog --msgbox "$dialog_message" 30 100
+
+    exit 1
+  fi
+
+  print_variables v_suitable_disks
+}
+
+function select_disks {
+  # shellcheck disable=SC2119
+  print_step_info_header
+
+  while true; do
+    local menu_entries_option=()
+
+    if [[ ${#v_suitable_disks[@]} -eq 1 ]]; then
+      local disk_selection_status=ON
+    else
+      local disk_selection_status=OFF
+    fi
+
+    for disk_id in "${v_suitable_disks[@]}"; do
+      menu_entries_option+=("$disk_id" "($block_device_basename)" "$disk_selection_status")
+    done
+
+    local dialog_message="Select the ZFS devices (multiple selections will be in mirror).
+
+Devices with mounted partitions, cdroms, and removable devices are not displayed!
+"
+    mapfile -t v_selected_disks < <(dialog --separate-output --checklist "$dialog_message" 30 100 $((${#menu_entries_option[@]} / 3)) "${menu_entries_option[@]}" 3>&1 1>&2 2>&3)
+
+    if [[ ${#v_selected_disks[@]} -gt 0 ]]; then
+      break
+    fi
+  done
+
+  print_variables v_selected_disks
+}
+
+function ask_swap_size {
+  # shellcheck disable=SC2119
+  print_step_info_header
+
+  local swap_size_invalid_message=
+
+  while [[ ! $v_swap_size =~ ^[0-9]+$ ]]; do
+    v_swap_size=$(dialog --inputbox "${swap_size_invalid_message}Enter the swap size in GiB (0 for no swap):" 30 100 2 3>&1 1>&2 2>&3)
+
+    swap_size_invalid_message="Invalid swap size! "
+  done
+
+  print_variables v_swap_size
+}
+
+function ask_free_tail_space {
+  # shellcheck disable=SC2119
+  print_step_info_header
+
+  local tail_space_invalid_message=
+
+  while [[ ! $v_free_tail_space =~ ^[0-9]+$ ]]; do
+    v_free_tail_space=$(dialog --inputbox "${tail_space_invalid_message}Enter the space to leave at the end of each disk (0 for none):" 30 100 0 3>&1 1>&2 2>&3)
+
+    tail_space_invalid_message="Invalid size! "
+  done
+
+  print_variables v_free_tail_space
+}
+
+function ask_zfs_arc_max_size {
+  # shellcheck disable=SC2119
+  print_step_info_header
+
+  local zfs_arc_max_invalid_message=
+
+  while [[ ! $v_zfs_arc_max_mb =~ ^[0-9]+$ ]]; do
+    v_zfs_arc_max_mb=$(dialog --inputbox "${zfs_arc_max_invalid_message}Enter ZFS ARC cache max size in Mb (minimum 64Mb, enter 0 for ZFS default value, the default will take up to 50% of memory):" 30 100 "$c_default_zfs_arc_max_mb" 3>&1 1>&2 2>&3)
+
+    zfs_arc_max_invalid_message="Invalid size! "
+  done
+
+  print_variables v_zfs_arc_max_mb
+}
+
+
+function ask_pool_names {
+  # shellcheck disable=SC2119
+  print_step_info_header
+
+  local bpool_name_invalid_message=
+
+  while [[ ! $v_bpool_name =~ ^[a-z][a-zA-Z_:.-]+$ ]]; do
+    v_bpool_name=$(dialog --inputbox "${bpool_name_invalid_message}Insert the name for the boot pool" 30 100 bpool 3>&1 1>&2 2>&3)
+
+    bpool_name_invalid_message="Invalid pool name! "
+  done
+  local rpool_name_invalid_message=
+
+  while [[ ! $v_rpool_name =~ ^[a-z][a-zA-Z_:.-]+$ ]]; do
+    v_rpool_name=$(dialog --inputbox "${rpool_name_invalid_message}Insert the name for the root pool" 30 100 rpool 3>&1 1>&2 2>&3)
+
+    rpool_name_invalid_message="Invalid pool name! "
+  done
+
+  print_variables v_bpool_name v_rpool_name
+}
+
+function ask_pool_tweaks {
+  # shellcheck disable=SC2119
+  print_step_info_header
+
+  v_bpool_tweaks=$(dialog --inputbox "Insert the tweaks for the boot pool" 30 100 -- "$c_default_bpool_tweaks" 3>&1 1>&2 2>&3)
+  v_rpool_tweaks=$(dialog --inputbox "Insert the tweaks for the root pool" 30 100 -- "$c_default_rpool_tweaks" 3>&1 1>&2 2>&3)
+
+  print_variables v_bpool_tweaks v_rpool_tweaks
+}
+
+
+function ask_root_password {
+  # shellcheck disable=SC2119
+  print_step_info_header
+
+  set +x
+  local password_invalid_message=
+  local password_repeat=-
+
+  while [[ "$v_root_password" != "$password_repeat" || "$v_root_password" == "" ]]; do
+    v_root_password=$(dialog --passwordbox "${password_invalid_message}Please enter the root account password (can't be empty):" 30 100 3>&1 1>&2 2>&3)
+    password_repeat=$(dialog --passwordbox "Please repeat the password:" 30 100 3>&1 1>&2 2>&3)
+
+    password_invalid_message="Passphrase empty, or not matching! "
+  done
+  set -x
+}
+
+function ask_encryption {
+  print_step_info_header
+
+  if dialog --defaultno --yesno 'Do you want to encrypt the root pool?' 30 100; then
+    v_encrypt_rpool=1
+  fi
+  set +x
+  if [[ $v_encrypt_rpool == "1" ]]; then
+    local passphrase_invalid_message=
+    local passphrase_repeat=-
+    while [[ "$v_passphrase" != "$passphrase_repeat" || ${#v_passphrase} -lt 8 ]]; do
+      v_passphrase=$(dialog --passwordbox "${passphrase_invalid_message}Please enter the passphrase for the root pool (8 chars min.):" 30 100 3>&1 1>&2 2>&3)
+      passphrase_repeat=$(dialog --passwordbox "Please repeat the passphrase:" 30 100 3>&1 1>&2 2>&3)
+
+      passphrase_invalid_message="Passphrase too short, or not matching! "
+    done
+  fi
+  set -x
+}
+
+function ask_zfs_experimental {
+  print_step_info_header
+
+  if dialog --defaultno --yesno 'Do you want to use experimental zfs module build?' 30 100; then
+    v_zfs_experimental=1
+  fi
+}
+
+function ask_hostname {
+  # shellcheck disable=SC2119
+  print_step_info_header
+
+  local hostname_invalid_message=
+
+  while [[ ! $v_hostname =~ ^[a-z][a-zA-Z_:.-]+$ ]]; do
+    v_hostname=$(dialog --inputbox "${hostname_invalid_message}Set the host name" 30 100 "$c_default_hostname" 3>&1 1>&2 2>&3)
+
+    hostname_invalid_message="Invalid host name! "
+  done
+
+  print_variables v_hostname
+}
+
+function determine_kernel_variant {
+  if dmidecode | grep -q vServer; then
+    v_kernel_variant="-cloud"
+  fi
+}
+
+function chroot_execute {
+  chroot $c_zfs_mount_dir bash -c "$1"
+}
+
+function unmount_and_export_fs {
+  # shellcheck disable=SC2119
+  print_step_info_header
+
+  for virtual_fs_dir in dev sys proc; do
+    umount --recursive --force --lazy "$c_zfs_mount_dir/$virtual_fs_dir"
+  done
+
+  local max_unmount_wait=5
+  echo -n "Waiting for virtual filesystems to unmount "
+
+  SECONDS=0
+
+  for virtual_fs_dir in dev sys proc; do
+    while mountpoint -q "$c_zfs_mount_dir/$virtual_fs_dir" && [[ $SECONDS -lt $max_unmount_wait ]]; do
+      sleep 0.5
+      echo -n .
+    done
+  done
+
+  echo
+
+  for virtual_fs_dir in dev sys proc; do
+    if mountpoint -q "$c_zfs_mount_dir/$virtual_fs_dir"; then
+      echo "Re-issuing umount for $c_zfs_mount_dir/$virtual_fs_dir"
+      umount --recursive --force --lazy "$c_zfs_mount_dir/$virtual_fs_dir"
+    fi
+  done
+
+  SECONDS=0
+  zpools_exported=99
+  echo "===========exporting zfs pools============="
+  set +e
+  while (( zpools_exported == 99 )) && (( SECONDS++ <= 60 )); do    
+    if zpool export -a 2> /dev/null; then
+      zpools_exported=1
+      echo "all zfs pools were succesfully exported"
+      break;
+    else
+      sleep 1
+     fi
+  done
+  set -e
+  if (( zpools_exported != 1 )); then
+    echo "failed to export zfs pools"
+    exit 1
+  fi
+}
+
+#################### MAIN ################################
+export LC_ALL=en_US.UTF-8
+export NCURSES_NO_UTF8_ACS=1
+
+check_prerequisites
+
+activate_debug
+
+display_intro_banner
+
+find_suitable_disks
+
+select_disks
+
+ask_swap_size
+
+ask_free_tail_space
+
+ask_pool_names
+
+ask_pool_tweaks
+
+ask_encryption
+
+ask_zfs_arc_max_size
+
+ask_zfs_experimental
+
+ask_root_password
+
+ask_hostname
+
+determine_kernel_variant
+
+clear
+
+echo "===========remove unused kernels in rescue system========="
+for kver in $(find /lib/modules/* -maxdepth 0 -type d | grep -v "$(uname -r)" | cut -s -d "/" -f 4); do
+  apt purge --yes "linux-headers-$kver"
+  apt purge --yes "linux-image-$kver"
+done
+
+echo "======= installing zfs on rescue system =========="
+  echo "zfs-dkms zfs-dkms/note-incompatible-licenses note true" | debconf-set-selections
+  apt-get install --yes software-properties-common
+  apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 8CF63AD3F06FC659
+  add-apt-repository 'deb http://ppa.launchpad.net/jonathonf/zfs/ubuntu focal main'
+  apt update
+  apt install --yes zfs-dkms zfsutils-linux
+  add-apt-repository -r 'deb http://ppa.launchpad.net/jonathonf/zfs/ubuntu focal main'
+  apt update
+  find /usr/local/sbin/ -type l -exec rm {} +
+  zfs --version
+
+echo "======= partitioning the disk =========="
+
+  if [[ $v_free_tail_space -eq 0 ]]; then
+    tail_space_parameter=0
+  else
+    tail_space_parameter="-${v_free_tail_space}G"
+  fi
+
+  for selected_disk in "${v_selected_disks[@]}"; do
+    wipefs --all --force "$selected_disk"
+    sgdisk -a1 -n1:24K:+1000K            -t1:EF02 "$selected_disk"
+    sgdisk -n2:0:+512M                   -t2:BF01 "$selected_disk" # Boot pool
+    sgdisk -n3:0:"$tail_space_parameter" -t3:BF01 "$selected_disk" # Root pool
+  done
+
+  udevadm settle
+
+echo "======= create zfs pools and datasets =========="
+
+  encryption_options=()
+  rpool_disks_partitions=()
+  bpool_disks_partitions=()
+
+  if [[ $v_encrypt_rpool == "1" ]]; then
+    encryption_options=(-O "encryption=aes-256-gcm" -O "keylocation=prompt" -O "keyformat=passphrase")
+  fi
+
+  for selected_disk in "${v_selected_disks[@]}"; do
+    rpool_disks_partitions+=("${selected_disk}-part3")
+    bpool_disks_partitions+=("${selected_disk}-part2")
+  done
+
+  if [[ ${#v_selected_disks[@]} -gt 1 ]]; then
+    pools_mirror_option=mirror
+  else
+    pools_mirror_option=
+  fi
+
+# shellcheck disable=SC2086
+zpool create \
+  $v_bpool_tweaks -O canmount=off -O devices=off \
+  -o cachefile=/etc/zfs/zpool.cache \
+  -O mountpoint=/boot -R $c_zfs_mount_dir -f \
+  $v_bpool_name $pools_mirror_option "${bpool_disks_partitions[@]}"
+
+# shellcheck disable=SC2086
+echo -n "$v_passphrase" | zpool create \
+  $v_rpool_tweaks \
+  -o cachefile=/etc/zfs/zpool.cache \
+  "${encryption_options[@]}" \
+  -O mountpoint=/ -R $c_zfs_mount_dir -f \
+  $v_rpool_name $pools_mirror_option "${rpool_disks_partitions[@]}"
+
+zfs create -o canmount=off -o mountpoint=none "$v_rpool_name/ROOT"
+zfs create -o canmount=off -o mountpoint=none "$v_bpool_name/BOOT"
+
+zfs create -o canmount=noauto -o mountpoint=/ "$v_rpool_name/ROOT/debian"
+zfs mount "$v_rpool_name/ROOT/debian"
+
+zfs create -o canmount=noauto -o mountpoint=/boot "$v_bpool_name/BOOT/debian"
+zfs mount "$v_bpool_name/BOOT/debian"
+
+zfs create                                 "$v_rpool_name/home"
+zfs create -o mountpoint=/root             "$v_rpool_name/home/root"
+zfs create -o canmount=off                 "$v_rpool_name/var"
+zfs create -o canmount=off                 "$v_rpool_name/var/lib"
+zfs create                                 "$v_rpool_name/var/log"
+zfs create                                 "$v_rpool_name/var/spool"
+
+zfs create -o com.sun:auto-snapshot=false  "$v_rpool_name/var/cache"
+zfs create -o com.sun:auto-snapshot=false  "$v_rpool_name/var/tmp"
+chmod 1777 "$c_zfs_mount_dir/var/tmp"
+
+zfs create                                 "$v_rpool_name/srv"
+
+zfs create -o canmount=off                 "$v_rpool_name/usr"
+zfs create                                 "$v_rpool_name/usr/local"
+
+zfs create                                 "$v_rpool_name/var/mail"
+
+zfs create -o com.sun:auto-snapshot=false -o canmount=on -o mountpoint=/tmp "$v_rpool_name/tmp"
+chmod 1777 "$c_zfs_mount_dir/tmp"
+
+if [[ $v_swap_size -gt 0 ]]; then
+  zfs create \
+    -V "${v_swap_size}G" -b "$(getconf PAGESIZE)" \
+    -o compression=zle -o logbias=throughput -o sync=always -o primarycache=metadata -o secondarycache=none -o com.sun:auto-snapshot=false \
+    "$v_rpool_name/swap"
+
+  udevadm settle
+
+  mkswap -f "/dev/zvol/$v_rpool_name/swap"
+fi
+
+echo "======= setting up initial system packages =========="
+debootstrap --arch=amd64 bullseye "$c_zfs_mount_dir" "$c_deb_packages_repo"
+
+zfs set devices=off "$v_rpool_name"
+
+echo "======= setting up the network =========="
+
+echo "$v_hostname" > $c_zfs_mount_dir/etc/hostname
+
+cat > "$c_zfs_mount_dir/etc/hosts" <<CONF
+127.0.1.1 ${v_hostname}
+127.0.0.1 localhost
+
+# The following lines are desirable for IPv6 capable hosts
+::1 ip6-localhost ip6-loopback
+fe00::0 ip6-localnet
+ff00::0 ip6-mcastprefix
+ff02::1 ip6-allnodes
+ff02::2 ip6-allrouters
+ff02::3 ip6-allhosts
+CONF
+
+ip6addr_prefix=$(ip -6 a s | grep -E "inet6.+global" | sed -nE 's/.+inet6\s(([0-9a-z]{1,4}:){4,4}).+/\1/p')
+
+cat <<CONF > /mnt/etc/systemd/network/10-eth0.network
+[Match]
+Name=eth0
+
+[Network]
+DHCP=ipv4
+Address=${ip6addr_prefix}:1/64
+Gateway=fe80::1
+CONF
+chroot_execute "systemctl enable systemd-networkd.service"
+
+
+cp /etc/resolv.conf $c_zfs_mount_dir/etc/resolv.conf
+
+echo "======= preparing the jail for chroot =========="
+for virtual_fs_dir in proc sys dev; do
+  mount --rbind "/$virtual_fs_dir" "$c_zfs_mount_dir/$virtual_fs_dir"
+done
+
+echo "======= setting apt repos =========="
+cat > "$c_zfs_mount_dir/etc/apt/sources.list" <<CONF
+deb $c_deb_packages_repo bullseye main contrib non-free
+deb $c_deb_packages_repo bullseye-updates main contrib non-free
+deb $c_deb_security_repo bullseye-security main contrib non-free
+deb $c_deb_packages_repo bullseye-backports main contrib non-free
+CONF
+
+chroot_execute "apt update"
+
+echo "======= setting locale, console and language =========="
+chroot_execute "apt install --yes -qq locales debconf-i18n apt-utils"
+sed -i 's/# en_US.UTF-8/en_US.UTF-8/' "$c_zfs_mount_dir/etc/locale.gen"
+sed -i 's/# fr_FR.UTF-8/fr_FR.UTF-8/' "$c_zfs_mount_dir/etc/locale.gen"
+sed -i 's/# fr_FR.UTF-8/fr_FR.UTF-8/' "$c_zfs_mount_dir/etc/locale.gen"
+sed -i 's/# de_AT.UTF-8/de_AT.UTF-8/' "$c_zfs_mount_dir/etc/locale.gen"
+sed -i 's/# de_DE.UTF-8/de_DE.UTF-8/' "$c_zfs_mount_dir/etc/locale.gen"
+
+chroot_execute 'cat <<CONF | debconf-set-selections
+locales locales/default_environment_locale      select  en_US.UTF-8
+keyboard-configuration  keyboard-configuration/store_defaults_in_debconf_db     boolean true
+keyboard-configuration  keyboard-configuration/variant  select  German
+keyboard-configuration  keyboard-configuration/unsupported_layout       boolean true
+keyboard-configuration  keyboard-configuration/modelcode        string  pc105
+keyboard-configuration  keyboard-configuration/unsupported_config_layout        boolean true
+keyboard-configuration  keyboard-configuration/layout   select  German
+keyboard-configuration  keyboard-configuration/layoutcode       string  de
+keyboard-configuration  keyboard-configuration/optionscode      string
+keyboard-configuration  keyboard-configuration/toggle   select  No toggling
+keyboard-configuration  keyboard-configuration/xkb-keymap       select  de
+keyboard-configuration  keyboard-configuration/switch   select  No temporary switch
+keyboard-configuration  keyboard-configuration/unsupported_config_options       boolean true
+keyboard-configuration  keyboard-configuration/ctrl_alt_bksp    boolean false
+keyboard-configuration  keyboard-configuration/variantcode      string
+keyboard-configuration  keyboard-configuration/model    select  Generic 105-key PC (intl.)
+keyboard-configuration  keyboard-configuration/altgr    select  The default for the keyboard layout
+keyboard-configuration  keyboard-configuration/compose  select  No compose key
+keyboard-configuration  keyboard-configuration/unsupported_options      boolean true
+console-setup   console-setup/fontsize-fb47     select  8x16
+console-setup   console-setup/store_defaults_in_debconf_db      boolean true
+console-setup   console-setup/codeset47 select  # Latin1 and Latin5 - western Europe and Turkic languages
+console-setup   console-setup/fontface47        select  Fixed
+console-setup   console-setup/fontsize  string  8x16
+console-setup   console-setup/charmap47 select  UTF-8
+console-setup   console-setup/fontsize-text47   select  8x16
+console-setup   console-setup/codesetcode       string  Lat15
+tzdata tzdata/Areas select Europe
+tzdata tzdata/Zones/Europe select Vienna
+grub-pc grub-pc/install_devices_empty   boolean true
+CONF'
+
+chroot_execute "dpkg-reconfigure locales -f noninteractive"
+echo -e "LC_ALL=en_US.UTF-8\nLANG=en_US.UTF-8\n" >> "$c_zfs_mount_dir/etc/environment"
+chroot_execute "apt install -qq --yes keyboard-configuration console-setup"
+chroot_execute "dpkg-reconfigure keyboard-configuration -f noninteractive"
+chroot_execute "dpkg-reconfigure console-setup -f noninteractive"
+chroot_execute "setupcon"
+
+chroot_execute "rm -f /etc/localtime /etc/timezone"
+chroot_execute "dpkg-reconfigure tzdata -f noninteractive "
+
+echo "======= installing latest kernel============="
+chroot_execute "apt install --yes linux-image${v_kernel_variant}-amd64 linux-headers${v_kernel_variant}-amd64"
+
+echo "======= installing aux packages =========="
+chroot_execute "apt install --yes man wget curl software-properties-common nano htop gnupg"
+
+echo "======= installing zfs packages =========="
+chroot_execute 'echo "zfs-dkms zfs-dkms/note-incompatible-licenses note true" | debconf-set-selections'
+
+if [[ $v_zfs_experimental == "1" ]]; then
+  chroot_execute "wget -O - https://terem42.github.io/zfs-debian/apt_pub.gpg | apt-key add -"
+  chroot_execute "add-apt-repository 'deb https://terem42.github.io/zfs-debian/public zfs-debian-experimental main'"
+  chroot_execute "apt update"
+  chroot_execute "apt install -t zfs-debian-experimental --yes zfs-initramfs zfs-dkms zfsutils-linux"
+else
+  chroot_execute "apt install --yes zfs-initramfs zfs-dkms zfsutils-linux"
+fi
+
+echo "======= installing OpenSSH and network tooling =========="
+chroot_execute "apt install --yes openssh-server net-tools"
+
+echo "======= setup OpenSSH  =========="
+mkdir -p "$c_zfs_mount_dir/root/.ssh/"
+cp /root/.ssh/authorized_keys "$c_zfs_mount_dir/root/.ssh/authorized_keys"
+sed -i 's/#PasswordAuthentication yes/PasswordAuthentication no/g' "$c_zfs_mount_dir/etc/ssh/sshd_config"
+sed -i 's/#PubkeyAuthentication yes/PubkeyAuthentication yes/g' "$c_zfs_mount_dir/etc/ssh/sshd_config"
+chroot_execute "rm /etc/ssh/ssh_host_*"
+chroot_execute "dpkg-reconfigure openssh-server -f noninteractive"
+
+echo "======= set root password =========="
+chroot_execute "echo root:$(printf "%q" "$v_root_password") | chpasswd"
+
+echo "======= setting up zfs cache =========="
+
+cp /etc/zfs/zpool.cache /mnt/etc/zfs/zpool.cache
+
+echo "========setting up zfs module parameters========"
+chroot_execute "echo options zfs zfs_arc_max=$((v_zfs_arc_max_mb * 1024 * 1024)) >> /etc/modprobe.d/zfs.conf"
+
+echo "======= setting up grub =========="
+chroot_execute "echo 'grub-pc grub-pc/install_devices_empty   boolean true' | debconf-set-selections"
+chroot_execute "DEBIAN_FRONTEND=noninteractive apt install --yes grub-legacy"
+chroot_execute "DEBIAN_FRONTEND=noninteractive apt install --yes grub-pc"
+chroot_execute "grub-install --recheck ${v_selected_disks[0]}"
+
+chroot_execute "sed -i 's/#GRUB_TERMINAL=console/GRUB_TERMINAL=console/g' /etc/default/grub"
+chroot_execute "sed -i 's|GRUB_CMDLINE_LINUX_DEFAULT=.*|GRUB_CMDLINE_LINUX_DEFAULT=\"net.ifnames=0\"|' /etc/default/grub"
+chroot_execute "sed -i 's|GRUB_CMDLINE_LINUX=\"\"|GRUB_CMDLINE_LINUX=\"root=ZFS=rpool/ROOT/debian\"|g' /etc/default/grub"
+
+chroot_execute "sed -i 's/quiet//g' /etc/default/grub"
+chroot_execute "sed -i 's/splash//g' /etc/default/grub"
+chroot_execute "echo 'GRUB_DISABLE_OS_PROBER=true'   >> /etc/default/grub"
+
+for ((i = 1; i < ${#v_selected_disks[@]}; i++)); do
+  dd if="${v_selected_disks[0]}-part1" of="${v_selected_disks[i]}-part1"
+done
+
+if [[ $v_encrypt_rpool == "1" ]]; then
+  echo "=========set up dropbear=============="
+
+  chroot_execute "apt install --yes dropbear-initramfs"
+
+  cp /root/.ssh/authorized_keys "$c_zfs_mount_dir/etc/dropbear-initramfs/authorized_keys"
+
+  cp "$c_zfs_mount_dir/etc/ssh/ssh_host_rsa_key" "$c_zfs_mount_dir/etc/ssh/ssh_host_rsa_key_temp"
+  chroot_execute "ssh-keygen -p -i -m pem -N '' -f /etc/ssh/ssh_host_rsa_key_temp"
+  chroot_execute "/usr/lib/dropbear/dropbearconvert openssh dropbear /etc/ssh/ssh_host_rsa_key_temp /etc/dropbear-initramfs/dropbear_rsa_host_key"
+  rm -rf "$c_zfs_mount_dir/etc/ssh/ssh_host_rsa_key_temp"
+
+  cp "$c_zfs_mount_dir/etc/ssh/ssh_host_ecdsa_key" "$c_zfs_mount_dir/etc/ssh/ssh_host_ecdsa_key_temp"
+  chroot_execute "ssh-keygen -p -i -m pem -N '' -f /etc/ssh/ssh_host_ecdsa_key_temp"
+  chroot_execute "/usr/lib/dropbear/dropbearconvert openssh dropbear /etc/ssh/ssh_host_ecdsa_key_temp /etc/dropbear-initramfs/dropbear_ecdsa_host_key"
+  chroot_execute "rm -rf /etc/ssh/ssh_host_ecdsa_key_temp"
+  rm -rf "$c_zfs_mount_dir/etc/ssh/ssh_host_ecdsa_key_temp"
+
+  rm -rf "$c_zfs_mount_dir/etc/dropbear-initramfs/dropbear_dss_host_key"
+fi
+
+echo "============setup root prompt============"
+cat > "$c_zfs_mount_dir/root/.bashrc" <<CONF
+export PS1='\[\033[01;31m\]\u\[\033[01;33m\]@\[\033[01;32m\]\h \[\033[01;33m\]\w \[\033[01;35m\]\$ \[\033[00m\]'
+umask 022
+export LS_OPTIONS='--color=auto -h'
+eval "\$(dircolors)"
+CONF
+
+echo "========running packages upgrade==========="
+chroot_execute "apt upgrade --yes"
+
+echo "===========add static route to initramfs via hook to add default routes for Hetzner due to Debian/Ubuntu initramfs DHCP bug ========="
+mkdir -p "$c_zfs_mount_dir/usr/share/initramfs-tools/scripts/init-premount"
+cat > "$c_zfs_mount_dir/usr/share/initramfs-tools/scripts/init-premount/static-route" <<'CONF'
+#!/bin/sh
+PREREQ=""
+prereqs()
+{
+    echo "$PREREQ"
+}
+
+case $1 in
+prereqs)
+    prereqs
+    exit 0
+    ;;
+esac
+
+. /scripts/functions
+# Begin real processing below this line
+
+configure_networking
+
+ip route add 172.31.1.1/255.255.255.255 dev ens3
+ip route add default via 172.31.1.1 dev ens3
+CONF
+
+chmod 755 "$c_zfs_mount_dir/usr/share/initramfs-tools/scripts/init-premount/static-route"
+
+echo "======= update initramfs =========="
+chroot_execute "update-initramfs -u -k all"
+
+echo "======= update grub =========="
+chroot_execute "update-grub"
+
+echo "======= setting up zed =========="
+if [[ $v_zfs_experimental == "1" ]]; then
+  chroot_execute "zfs set canmount=noauto rpool"
+else
+  initial_load_debian_zed_cache
+fi
+
+echo "======= setting mountpoints =========="
+chroot_execute "zfs set mountpoint=legacy $v_bpool_name/BOOT/debian"
+chroot_execute "echo $v_bpool_name/BOOT/debian /boot zfs nodev,relatime,x-systemd.requires=zfs-mount.service,x-systemd.device-timeout=10 0 0 > /etc/fstab"
+
+chroot_execute "zfs set mountpoint=legacy $v_rpool_name/var/log"
+chroot_execute "echo $v_rpool_name/var/log /var/log zfs nodev,relatime 0 0 >> /etc/fstab"
+chroot_execute "zfs set mountpoint=legacy $v_rpool_name/var/spool"
+chroot_execute "echo $v_rpool_name/var/spool /var/spool zfs nodev,relatime 0 0 >> /etc/fstab"
+chroot_execute "zfs set mountpoint=legacy $v_rpool_name/var/tmp"
+chroot_execute "echo $v_rpool_name/var/tmp /var/tmp zfs nodev,relatime 0 0 >> /etc/fstab"
+chroot_execute "zfs set mountpoint=legacy $v_rpool_name/tmp"
+chroot_execute "echo $v_rpool_name/tmp /tmp zfs nodev,relatime 0 0 >> /etc/fstab"
+
+echo "========= add swap, if defined"
+if [[ $v_swap_size -gt 0 ]]; then
+  chroot_execute "echo /dev/zvol/$v_rpool_name/swap none swap discard 0 0 >> /etc/fstab"
+fi
+
+chroot_execute "echo RESUME=none > /etc/initramfs-tools/conf.d/resume"
+
+echo "======= unmounting filesystems and zfs pools =========="
+unmount_and_export_fs
+
+echo "======== setup complete, rebooting ==============="
+reboot

hetzner-ubuntu18-zfs-setup.sh

@@ -40,7 +40,7 @@ c_deb_security_repo=http://mirror.hetzner.de/ubuntu/security
 
 c_default_zfs_arc_max_mb=250
 c_default_bpool_tweaks="-o ashift=12 -O compression=lz4"
-c_default_rpool_tweaks="-o ashift=12 -O acltype=posixacl -O compression=lz4 -O dnodesize=auto -O relatime=on -O xattr=sa -O normalization=formD"
+c_default_rpool_tweaks="-o ashift=12 -O acltype=posixacl -O compression=zstd-9 -O dnodesize=auto -O relatime=on -O xattr=sa -O normalization=formD"
 c_default_hostname=terem
 c_zfs_mount_dir=/mnt
 c_log_dir=$(dirname "$(mktemp)")/zfs-hetzner-vm
@@ -62,7 +62,9 @@ function print_step_info_header {
 ###############################################################################
 # ${FUNCNAME[1]}"
 
-  [[ "${1:-}" != "" ]] && echo -n " $1" || true
+  if [[ "${1:-}" != "" ]]; then
+    echo -n " $1" 
+  fi
 
   echo "
 ###############################################################################
@@ -106,7 +108,7 @@ This script will prepare the ZFS pools, then install and configure minimal Ubunt
 The script with minimal changes may be used on any other hosting provider  supporting KVM virtualization and offering Debian-based rescue system.
 In order to stop the procedure, hit Esc twice during dialogs (excluding yes/no ones), or Ctrl+C while any operation is running.
 '
-  dialog --ascii-lines --msgbox "$dialog_message" 30 100
+  dialog --msgbox "$dialog_message" 30 100
 }
 
 function store_os_distro_information {
@@ -173,9 +175,9 @@ LOG
   if [[ ${#v_suitable_disks[@]} -eq 0 ]]; then
     local dialog_message='No suitable disks have been found!
 
-If you think this is a bug, please open an issue on https://github.com/andrey42/zfs-hetzner-vm/issues, and attach the file `'"$c_disks_log"'`.
+If you think this is a bug, please open an issue on https://github.com/terem42/zfs-hetzner-vm/issues, and attach the file `'"$c_disks_log"'`.
 '
-    dialog --ascii-lines --msgbox "$dialog_message" 30 100
+    dialog --msgbox "$dialog_message" 30 100
 
     exit 1
   fi
@@ -204,7 +206,7 @@ function select_disks {
 
 Devices with mounted partitions, cdroms, and removable devices are not displayed!
 "
-    mapfile -t v_selected_disks < <(dialog --ascii-lines --separate-output --checklist "$dialog_message" 30 100 $((${#menu_entries_option[@]} / 3)) "${menu_entries_option[@]}" 3>&1 1>&2 2>&3)
+    mapfile -t v_selected_disks < <(dialog --separate-output --checklist "$dialog_message" 30 100 $((${#menu_entries_option[@]} / 3)) "${menu_entries_option[@]}" 3>&1 1>&2 2>&3)
 
     if [[ ${#v_selected_disks[@]} -gt 0 ]]; then
       break
@@ -221,7 +223,7 @@ function ask_swap_size {
   local swap_size_invalid_message=
 
   while [[ ! $v_swap_size =~ ^[0-9]+$ ]]; do
-    v_swap_size=$(dialog --ascii-lines --inputbox "${swap_size_invalid_message}Enter the swap size in GiB (0 for no swap):" 30 100 2 3>&1 1>&2 2>&3)
+    v_swap_size=$(dialog --inputbox "${swap_size_invalid_message}Enter the swap size in GiB (0 for no swap):" 30 100 2 3>&1 1>&2 2>&3)
 
     swap_size_invalid_message="Invalid swap size! "
   done
@@ -236,7 +238,7 @@ function ask_free_tail_space {
   local tail_space_invalid_message=
 
   while [[ ! $v_free_tail_space =~ ^[0-9]+$ ]]; do
-    v_free_tail_space=$(dialog --ascii-lines --inputbox "${tail_space_invalid_message}Enter the space to leave at the end of each disk (0 for none):" 30 100 0 3>&1 1>&2 2>&3)
+    v_free_tail_space=$(dialog --inputbox "${tail_space_invalid_message}Enter the space to leave at the end of each disk (0 for none):" 30 100 0 3>&1 1>&2 2>&3)
 
     tail_space_invalid_message="Invalid size! "
   done
@@ -251,7 +253,7 @@ function ask_zfs_arc_max_size {
   local zfs_arc_max_invalid_message=
 
   while [[ ! $v_zfs_arc_max_mb =~ ^[0-9]+$ ]]; do
-    v_zfs_arc_max_mb=$(dialog --ascii-lines --inputbox "${zfs_arc_max_invalid_message}Enter ZFS ARC cache max size in Mb (minimum 64Mb, enter 0 for ZFS default value, the default will take up to 50% of memory):" 30 100 "$c_default_zfs_arc_max_mb" 3>&1 1>&2 2>&3)
+    v_zfs_arc_max_mb=$(dialog --inputbox "${zfs_arc_max_invalid_message}Enter ZFS ARC cache max size in Mb (minimum 64Mb, enter 0 for ZFS default value, the default will take up to 50% of memory):" 30 100 "$c_default_zfs_arc_max_mb" 3>&1 1>&2 2>&3)
 
     zfs_arc_max_invalid_message="Invalid size! "
   done
@@ -267,14 +269,14 @@ function ask_pool_names {
   local bpool_name_invalid_message=
 
   while [[ ! $v_bpool_name =~ ^[a-z][a-zA-Z_:.-]+$ ]]; do
-    v_bpool_name=$(dialog --ascii-lines --inputbox "${bpool_name_invalid_message}Insert the name for the boot pool" 30 100 bpool 3>&1 1>&2 2>&3)
+    v_bpool_name=$(dialog --inputbox "${bpool_name_invalid_message}Insert the name for the boot pool" 30 100 bpool 3>&1 1>&2 2>&3)
 
     bpool_name_invalid_message="Invalid pool name! "
   done
   local rpool_name_invalid_message=
 
   while [[ ! $v_rpool_name =~ ^[a-z][a-zA-Z_:.-]+$ ]]; do
-    v_rpool_name=$(dialog --ascii-lines --inputbox "${rpool_name_invalid_message}Insert the name for the root pool" 30 100 rpool 3>&1 1>&2 2>&3)
+    v_rpool_name=$(dialog --inputbox "${rpool_name_invalid_message}Insert the name for the root pool" 30 100 rpool 3>&1 1>&2 2>&3)
 
     rpool_name_invalid_message="Invalid pool name! "
   done
@@ -286,8 +288,8 @@ function ask_pool_tweaks {
   # shellcheck disable=SC2119
   print_step_info_header
 
-  v_bpool_tweaks=$(dialog --ascii-lines --inputbox "Insert the tweaks for the boot pool" 30 100 -- "$c_default_bpool_tweaks" 3>&1 1>&2 2>&3)
+  v_bpool_tweaks=$(dialog --inputbox "Insert the tweaks for the boot pool" 30 100 -- "$c_default_bpool_tweaks" 3>&1 1>&2 2>&3)
-  v_rpool_tweaks=$(dialog --ascii-lines --inputbox "Insert the tweaks for the root pool" 30 100 -- "$c_default_rpool_tweaks" 3>&1 1>&2 2>&3)
+  v_rpool_tweaks=$(dialog --inputbox "Insert the tweaks for the root pool" 30 100 -- "$c_default_rpool_tweaks" 3>&1 1>&2 2>&3)
 
   print_variables v_bpool_tweaks v_rpool_tweaks
 }
@@ -302,8 +304,8 @@ function ask_root_password {
   local password_repeat=-
 
   while [[ "$v_root_password" != "$password_repeat" || "$v_root_password" == "" ]]; do
-    v_root_password=$(dialog --ascii-lines --passwordbox "${password_invalid_message}Please enter the root account password (can't be empty):" 30 100 3>&1 1>&2 2>&3)
+    v_root_password=$(dialog --passwordbox "${password_invalid_message}Please enter the root account password (can't be empty):" 30 100 3>&1 1>&2 2>&3)
-    password_repeat=$(dialog --ascii-lines --passwordbox "Please repeat the password:" 30 100 3>&1 1>&2 2>&3)
+    password_repeat=$(dialog --passwordbox "Please repeat the password:" 30 100 3>&1 1>&2 2>&3)
 
     password_invalid_message="Passphrase empty, or not matching! "
   done
@@ -313,7 +315,7 @@ function ask_root_password {
 function ask_encryption {
   print_step_info_header
 
-  if dialog --ascii-lines --yesno 'Do you want to encrypt the root pool?' 30 100; then
+  if dialog --defaultno --yesno 'Do you want to encrypt the root pool?' 30 100; then
     v_encrypt_rpool=1
   fi
   set +x
@@ -321,8 +323,8 @@ function ask_encryption {
     local passphrase_invalid_message=
     local passphrase_repeat=-
     while [[ "$v_passphrase" != "$passphrase_repeat" || ${#v_passphrase} -lt 8 ]]; do
-      v_passphrase=$(dialog --ascii-lines --passwordbox "${passphrase_invalid_message}Please enter the passphrase for the root pool (8 chars min.):" 30 100 3>&1 1>&2 2>&3)
+      v_passphrase=$(dialog --passwordbox "${passphrase_invalid_message}Please enter the passphrase for the root pool (8 chars min.):" 30 100 3>&1 1>&2 2>&3)
-      passphrase_repeat=$(dialog --ascii-lines --passwordbox "Please repeat the passphrase:" 30 100 3>&1 1>&2 2>&3)
+      passphrase_repeat=$(dialog --passwordbox "Please repeat the passphrase:" 30 100 3>&1 1>&2 2>&3)
 
       passphrase_invalid_message="Passphrase too short, or not matching! "
     done
@@ -333,7 +335,7 @@ function ask_encryption {
 function ask_zfs_experimental {
   print_step_info_header
 
-  if dialog --ascii-lines --yesno 'Do you want to use experimental zfs module build?' 30 100; then
+  if dialog --defaultno --yesno 'Do you want to use experimental zfs module build?' 30 100; then
     v_zfs_experimental=1
   fi
 }
@@ -345,7 +347,7 @@ function ask_hostname {
   local hostname_invalid_message=
 
   while [[ ! $v_hostname =~ ^[a-z][a-zA-Z_:.-]+$ ]]; do
-    v_hostname=$(dialog --ascii-lines --inputbox "${hostname_invalid_message}Set the host name" 30 100 "$c_default_hostname" 3>&1 1>&2 2>&3)
+    v_hostname=$(dialog --inputbox "${hostname_invalid_message}Set the host name" 30 100 "$c_default_hostname" 3>&1 1>&2 2>&3)
 
     hostname_invalid_message="Invalid host name! "
   done
@@ -399,8 +401,8 @@ function unmount_and_export_fs {
   echo "===========exporting zfs pools============="
   set +e
   while (( zpools_exported == 99 )) && (( SECONDS++ <= 60 )); do
-    zpool export -a 2> /dev/null
+    
-    if [[ $? == 0 ]]; then
+    if zpool export -a 2> /dev/null; then
       zpools_exported=1
       echo "all zfs pools were succesfully exported"
       break;
@@ -417,6 +419,7 @@ function unmount_and_export_fs {
 
 #################### MAIN ################################
 export LC_ALL=en_US.UTF-8
+export NCURSES_NO_UTF8_ACS=1
 
 check_prerequisites
 
@@ -458,10 +461,14 @@ done
 
 echo "======= installing zfs on rescue system =========="
   echo "zfs-dkms zfs-dkms/note-incompatible-licenses note true" | debconf-set-selections
-
+  apt-get install --yes software-properties-common
+  apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 8CF63AD3F06FC659
+  add-apt-repository 'deb http://ppa.launchpad.net/jonathonf/zfs/ubuntu focal main'
   apt update
-  apt install --yes -t buster-backports libelf-dev zfs-dkms
+  apt install --yes zfs-dkms zfsutils-linux
-  modprobe zfs
+  add-apt-repository -r 'deb http://ppa.launchpad.net/jonathonf/zfs/ubuntu focal main'
+  apt update
+  find /usr/local/sbin/ -type l -exec rm {} +
   zfs --version
 
 echo "======= partitioning the disk =========="
@@ -473,7 +480,7 @@ echo "======= partitioning the disk =========="
   fi
 
   for selected_disk in "${v_selected_disks[@]}"; do
-    wipefs --all "$selected_disk"
+    wipefs --all --force "$selected_disk"
     sgdisk -a1 -n1:24K:+1000K            -t1:EF02 "$selected_disk"
     sgdisk -n2:0:+512M                   -t2:BF01 "$selected_disk" # Boot pool
     sgdisk -n3:0:"$tail_space_parameter" -t3:BF01 "$selected_disk" # Root pool
@@ -502,13 +509,17 @@ echo "======= create zfs pools and datasets =========="
     pools_mirror_option=
   fi
 
+# shellcheck disable=SC2086
 zpool create \
   $v_bpool_tweaks -O canmount=off -O devices=off \
+  -o cachefile=/etc/zfs/zpool.cache \
   -O mountpoint=/boot -R $c_zfs_mount_dir -f \
   $v_bpool_name $pools_mirror_option "${bpool_disks_partitions[@]}"
 
+# shellcheck disable=SC2086
 echo -n "$v_passphrase" | zpool create \
   $v_rpool_tweaks \
+  -o cachefile=/etc/zfs/zpool.cache \
   "${encryption_options[@]}" \
   -O mountpoint=/ -R $c_zfs_mount_dir -f \
   $v_rpool_name $pools_mirror_option "${rpool_disks_partitions[@]}"
@@ -618,7 +629,7 @@ CONF
 chroot_execute "apt update"
 
 echo "======= setting locale, console and language =========="
-chroot_execute "apt install --yes -qq locales debconf-i18n apt-utils"
+chroot_execute "apt install --yes -qq locales debconf-i18n apt-utils keyboard-configuration console-setup"
 sed -i 's/# en_US.UTF-8/en_US.UTF-8/' "$c_zfs_mount_dir/etc/locale.gen"
 sed -i 's/# fr_FR.UTF-8/fr_FR.UTF-8/' "$c_zfs_mount_dir/etc/locale.gen"
 sed -i 's/# fr_FR.UTF-8/fr_FR.UTF-8/' "$c_zfs_mount_dir/etc/locale.gen"
@@ -660,7 +671,6 @@ CONF'
 
 chroot_execute "dpkg-reconfigure locales -f noninteractive"
 echo -e "LC_ALL=en_US.UTF-8\nLANG=en_US.UTF-8\n" >> "$c_zfs_mount_dir/etc/environment"
-chroot_execute "apt install -qq --yes keyboard-configuration console-setup"
 chroot_execute "dpkg-reconfigure keyboard-configuration -f noninteractive"
 chroot_execute "dpkg-reconfigure console-setup -f noninteractive"
 chroot_execute "setupcon"
@@ -675,26 +685,23 @@ if [[ $v_kernel_variant == "-virtual" ]]; then
   chroot_execute "DEBIAN_FRONTEND=noninteractive apt install --yes linux-image-extra-virtual-hwe-18.04"
 fi
 
-
 echo "======= installing aux packages =========="
 chroot_execute "apt install --yes man wget curl software-properties-common nano htop gnupg"
 chroot_execute "systemctl disable thermald"
 
 echo "======= installing zfs packages =========="
-if [[ $v_zfs_experimental == "1" ]]; then
-  chroot_execute "wget -O - https://andrey42.github.io/zfs-ubuntu/apt_pub.gpg | apt-key add -"
-  chroot_execute "add-apt-repository 'deb https://andrey42.github.io/zfs-ubuntu/public zfs-debian-experimental main'"
-  chroot_execute "apt update"
-else
-  chroot_execute "add-apt-repository --yes ppa:jonathonf/zfs"
-fi
 chroot_execute 'echo "zfs-dkms zfs-dkms/note-incompatible-licenses note true" | debconf-set-selections'
 
 if [[ $v_zfs_experimental == "1" ]]; then
+  chroot_execute "wget -O - https://terem42.github.io/zfs-debian/apt_pub.gpg | apt-key add -"
+  chroot_execute "add-apt-repository 'deb https://terem42.github.io/zfs-debian/public zfs-debian-experimental main'"
+  chroot_execute "apt update"
   chroot_execute "apt install -t zfs-debian-experimental --yes zfs-initramfs zfs-dkms zfsutils-linux"
 else
+  chroot_execute "add-apt-repository --yes ppa:jonathonf/zfs"
   chroot_execute "apt install --yes zfs-initramfs zfs-dkms zfsutils-linux"
 fi
+
 echo "======= installing OpenSSH and network tooling =========="
 chroot_execute "apt install --yes openssh-server net-tools"
 
@@ -709,25 +716,8 @@ chroot_execute "dpkg-reconfigure openssh-server -f noninteractive"
 echo "======= set root password =========="
 chroot_execute "echo root:$(printf "%q" "$v_root_password") | chpasswd"
 
-echo "======= setting up zfs services =========="
+echo "======= setting up zfs cache =========="
-chroot_execute "cat > /etc/systemd/system/zfs-import-bpool.service <<UNIT
+cp /etc/zfs/zpool.cache /mnt/etc/zfs/zpool.cache
-[Unit]
-DefaultDependencies=no
-Before=zfs-import-scan.service
-Before=zfs-import-cache.service
-
-[Service]
-Type=oneshot
-RemainAfterExit=yes
-ExecStartPre=/bin/sh -c '[ -f /etc/zfs/zpool.cache ] && mv /etc/zfs/zpool.cache /etc/zfs/preboot_zpool.cache || true'
-ExecStart=/sbin/zpool import -N -o cachefile=none $v_bpool_name
-ExecStartPost=/bin/sh -c '[ -f /etc/zfs/preboot_zpool.cache ] && mv /etc/zfs/preboot_zpool.cache /etc/zfs/zpool.cache || true'
-
-[Install]
-WantedBy=zfs-import.target
-UNIT"
-
-chroot_execute "systemctl enable zfs-import-bpool.service"
 
 echo "========setting up zfs module parameters========"
 chroot_execute "echo options zfs zfs_arc_max=$((v_zfs_arc_max_mb * 1024 * 1024)) >> /etc/modprobe.d/zfs.conf"
@@ -832,7 +822,7 @@ chroot_execute "zfs set canmount=noauto rpool"
 
 echo "======= setting mountpoints =========="
 chroot_execute "zfs set mountpoint=legacy $v_bpool_name/BOOT/ubuntu"
-chroot_execute "echo $v_bpool_name/BOOT/ubuntu /boot zfs nodev,relatime,x-systemd.requires=zfs-import-bpool.service 0 0 > /etc/fstab"
+chroot_execute "echo $v_bpool_name/BOOT/ubuntu /boot zfs nodev,relatime,x-systemd.requires=zfs-mount.service,x-systemd.device-timeout=10 0 0 > /etc/fstab"
 
 chroot_execute "zfs set mountpoint=legacy $v_rpool_name/var/log"
 chroot_execute "echo $v_rpool_name/var/log /var/log zfs nodev,relatime 0 0 >> /etc/fstab"
@@ -844,7 +834,10 @@ chroot_execute "zfs set mountpoint=legacy $v_rpool_name/tmp"
 chroot_execute "echo $v_rpool_name/tmp /tmp zfs nodev,relatime 0 0 >> /etc/fstab"
 
 echo "========= add swap, if defined"
-[[ $v_swap_size -gt 0 ]] && chroot_execute "echo /dev/zvol/$v_rpool_name/swap none swap discard 0 0 >> /etc/fstab" || true
+if [[ $v_swap_size -gt 0 ]]; then
+  chroot_execute "echo /dev/zvol/$v_rpool_name/swap none swap discard 0 0 >> /etc/fstab"
+fi
+
 chroot_execute "echo RESUME=none > /etc/initramfs-tools/conf.d/resume"
 
 echo "======= unmounting filesystems and zfs pools =========="

hetzner-ubuntu20-zfs-setup.sh

@@ -0,0 +1,848 @@
+#!/bin/bash
+
+: <<'end_header_info'
+(c) Andrey Prokopenko job@terem.fr
+fully automatic script to install Ubuntu 20 LTS with ZFS root on Hetzner VPS
+WARNING: all data on the disk will be destroyed
+How to use: add SSH key to the rescue console, set it OS to linux64, then press "mount rescue and power cycle" button
+Next, connect via SSH to console, and run the script
+Answer script questions about desired hostname and ZFS ARC cache size
+To cope with network failures its higly recommended to run the script inside screen console
+screen -dmS zfs
+screen -r zfs
+To detach from screen console, hit Ctrl-d then a
+end_header_info
+
+set -o errexit
+set -o pipefail
+set -o nounset
+
+# Variables
+v_bpool_name=
+v_bpool_tweaks=
+v_rpool_name=
+v_rpool_tweaks=
+declare -a v_selected_disks
+v_swap_size=                 # integer
+v_free_tail_space=           # integer
+v_hostname=
+v_kernel_variant=
+v_zfs_arc_max_mb=
+v_root_password=
+v_encrypt_rpool=             # 0=false, 1=true
+v_passphrase=
+v_zfs_experimental=
+v_suitable_disks=()
+
+# Constants
+c_deb_packages_repo=http://mirror.hetzner.de/ubuntu/packages
+c_deb_security_repo=http://mirror.hetzner.de/ubuntu/security
+
+c_default_zfs_arc_max_mb=250
+c_default_bpool_tweaks="-o ashift=12 -O compression=lz4"
+c_default_rpool_tweaks="-o ashift=12 -O acltype=posixacl -O compression=zstd-9 -O dnodesize=auto -O relatime=on -O xattr=sa -O normalization=formD"
+c_default_hostname=terem
+c_zfs_mount_dir=/mnt
+c_log_dir=$(dirname "$(mktemp)")/zfs-hetzner-vm
+c_install_log=$c_log_dir/install.log
+c_lsb_release_log=$c_log_dir/lsb_release.log
+c_disks_log=$c_log_dir/disks.log
+
+function activate_debug {
+  mkdir -p "$c_log_dir"
+
+  exec 5> "$c_install_log"
+  BASH_XTRACEFD="5"
+  set -x
+}
+
+# shellcheck disable=SC2120
+function print_step_info_header {
+  echo -n "
+###############################################################################
+# ${FUNCNAME[1]}"
+
+  if [[ "${1:-}" != "" ]]; then
+    echo -n " $1" 
+  fi
+
+  echo "
+###############################################################################
+"
+}
+
+function print_variables {
+  for variable_name in "$@"; do
+    declare -n variable_reference="$variable_name"
+
+    echo -n "$variable_name:"
+
+    case "$(declare -p "$variable_name")" in
+    "declare -a"* )
+      for entry in "${variable_reference[@]}"; do
+        echo -n " \"$entry\""
+      done
+      ;;
+    "declare -A"* )
+      for key in "${!variable_reference[@]}"; do
+        echo -n " $key=\"${variable_reference[$key]}\""
+      done
+      ;;
+    * )
+      echo -n " $variable_reference"
+      ;;
+    esac
+
+    echo
+  done
+
+  echo
+}
+
+function display_intro_banner {
+  # shellcheck disable=SC2119
+  print_step_info_header
+
+  local dialog_message='Hello!
+This script will prepare the ZFS pools, then install and configure minimal Ubuntu 20 LTS with ZFS root on Hetzner hosting VPS instance
+The script with minimal changes may be used on any other hosting provider  supporting KVM virtualization and offering Debian-based rescue system.
+In order to stop the procedure, hit Esc twice during dialogs (excluding yes/no ones), or Ctrl+C while any operation is running.
+'
+  dialog --msgbox "$dialog_message" 30 100
+}
+
+function store_os_distro_information {
+  # shellcheck disable=SC2119
+  print_step_info_header
+
+  lsb_release --all > "$c_lsb_release_log"
+}
+
+function check_prerequisites {
+  # shellcheck disable=SC2119
+  print_step_info_header
+  if [[ $(id -u) -ne 0 ]]; then
+    echo 'This script must be run with administrative privileges!'
+    exit 1
+  fi
+  if [[ ! -r /root/.ssh/authorized_keys ]]; then
+    echo "SSH pubkey file is absent, please add it to the rescue system setting, then reboot into rescue system and run the script"
+    exit 1
+  fi
+  if ! dpkg-query --showformat="\${Status}" -W dialog 2> /dev/null | grep -q "install ok installed"; then
+    apt install --yes dialog
+  fi
+}
+
+
+function find_suitable_disks {
+  # shellcheck disable=SC2119
+  print_step_info_header
+
+  udevadm trigger
+
+  # shellcheck disable=SC2012
+  ls -l /dev/disk/by-id | tail -n +2 | perl -lane 'print "@F[8..10]"' > "$c_disks_log"
+
+  local candidate_disk_ids
+  local mounted_devices
+
+  candidate_disk_ids=$(find /dev/disk/by-id -regextype awk -regex '.+/(ata|nvme|scsi)-.+' -not -regex '.+-part[0-9]+$' | sort)
+  mounted_devices="$(df | awk 'BEGIN {getline} {print $1}' | xargs -n 1 lsblk -no pkname 2> /dev/null | sort -u || true)"
+
+  while read -r disk_id || [[ -n "$disk_id" ]]; do
+    local device_info
+
+    device_info="$(udevadm info --query=property "$(readlink -f "$disk_id")")"
+    block_device_basename="$(basename "$(readlink -f "$disk_id")")"
+
+    if ! grep -q '^ID_TYPE=cd$' <<< "$device_info"; then
+      if ! grep -q "^$block_device_basename\$" <<< "$mounted_devices"; then
+        v_suitable_disks+=("$disk_id")
+      fi
+    fi
+
+    cat >> "$c_disks_log" << LOG
+
+## DEVICE: $disk_id ################################
+
+$(udevadm info --query=property "$(readlink -f "$disk_id")")
+
+LOG
+
+  done < <(echo -n "$candidate_disk_ids")
+
+  if [[ ${#v_suitable_disks[@]} -eq 0 ]]; then
+    local dialog_message='No suitable disks have been found!
+
+If you think this is a bug, please open an issue on https://github.com/terem42/zfs-hetzner-vm/issues, and attach the file `'"$c_disks_log"'`.
+'
+    dialog --msgbox "$dialog_message" 30 100
+
+    exit 1
+  fi
+
+  print_variables v_suitable_disks
+}
+
+function select_disks {
+  # shellcheck disable=SC2119
+  print_step_info_header
+
+  while true; do
+    local menu_entries_option=()
+
+    if [[ ${#v_suitable_disks[@]} -eq 1 ]]; then
+      local disk_selection_status=ON
+    else
+      local disk_selection_status=OFF
+    fi
+
+    for disk_id in "${v_suitable_disks[@]}"; do
+      menu_entries_option+=("$disk_id" "($block_device_basename)" "$disk_selection_status")
+    done
+
+    local dialog_message="Select the ZFS devices (multiple selections will be in mirror).
+
+Devices with mounted partitions, cdroms, and removable devices are not displayed!
+"
+    mapfile -t v_selected_disks < <(dialog --separate-output --checklist "$dialog_message" 30 100 $((${#menu_entries_option[@]} / 3)) "${menu_entries_option[@]}" 3>&1 1>&2 2>&3)
+
+    if [[ ${#v_selected_disks[@]} -gt 0 ]]; then
+      break
+    fi
+  done
+
+  print_variables v_selected_disks
+}
+
+function ask_swap_size {
+  # shellcheck disable=SC2119
+  print_step_info_header
+
+  local swap_size_invalid_message=
+
+  while [[ ! $v_swap_size =~ ^[0-9]+$ ]]; do
+    v_swap_size=$(dialog --inputbox "${swap_size_invalid_message}Enter the swap size in GiB (0 for no swap):" 30 100 2 3>&1 1>&2 2>&3)
+
+    swap_size_invalid_message="Invalid swap size! "
+  done
+
+  print_variables v_swap_size
+}
+
+function ask_free_tail_space {
+  # shellcheck disable=SC2119
+  print_step_info_header
+
+  local tail_space_invalid_message=
+
+  while [[ ! $v_free_tail_space =~ ^[0-9]+$ ]]; do
+    v_free_tail_space=$(dialog --inputbox "${tail_space_invalid_message}Enter the space to leave at the end of each disk (0 for none):" 30 100 0 3>&1 1>&2 2>&3)
+
+    tail_space_invalid_message="Invalid size! "
+  done
+
+  print_variables v_free_tail_space
+}
+
+function ask_zfs_arc_max_size {
+  # shellcheck disable=SC2119
+  print_step_info_header
+
+  local zfs_arc_max_invalid_message=
+
+  while [[ ! $v_zfs_arc_max_mb =~ ^[0-9]+$ ]]; do
+    v_zfs_arc_max_mb=$(dialog --inputbox "${zfs_arc_max_invalid_message}Enter ZFS ARC cache max size in Mb (minimum 64Mb, enter 0 for ZFS default value, the default will take up to 50% of memory):" 30 100 "$c_default_zfs_arc_max_mb" 3>&1 1>&2 2>&3)
+
+    zfs_arc_max_invalid_message="Invalid size! "
+  done
+
+  print_variables v_zfs_arc_max_mb
+}
+
+
+function ask_pool_names {
+  # shellcheck disable=SC2119
+  print_step_info_header
+
+  local bpool_name_invalid_message=
+
+  while [[ ! $v_bpool_name =~ ^[a-z][a-zA-Z_:.-]+$ ]]; do
+    v_bpool_name=$(dialog --inputbox "${bpool_name_invalid_message}Insert the name for the boot pool" 30 100 bpool 3>&1 1>&2 2>&3)
+
+    bpool_name_invalid_message="Invalid pool name! "
+  done
+  local rpool_name_invalid_message=
+
+  while [[ ! $v_rpool_name =~ ^[a-z][a-zA-Z_:.-]+$ ]]; do
+    v_rpool_name=$(dialog --inputbox "${rpool_name_invalid_message}Insert the name for the root pool" 30 100 rpool 3>&1 1>&2 2>&3)
+
+    rpool_name_invalid_message="Invalid pool name! "
+  done
+
+  print_variables v_bpool_name v_rpool_name
+}
+
+function ask_pool_tweaks {
+  # shellcheck disable=SC2119
+  print_step_info_header
+
+  v_bpool_tweaks=$(dialog --inputbox "Insert the tweaks for the boot pool" 30 100 -- "$c_default_bpool_tweaks" 3>&1 1>&2 2>&3)
+  v_rpool_tweaks=$(dialog --inputbox "Insert the tweaks for the root pool" 30 100 -- "$c_default_rpool_tweaks" 3>&1 1>&2 2>&3)
+
+  print_variables v_bpool_tweaks v_rpool_tweaks
+}
+
+
+function ask_root_password {
+  # shellcheck disable=SC2119
+  print_step_info_header
+
+  set +x
+  local password_invalid_message=
+  local password_repeat=-
+
+  while [[ "$v_root_password" != "$password_repeat" || "$v_root_password" == "" ]]; do
+    v_root_password=$(dialog --passwordbox "${password_invalid_message}Please enter the root account password (can't be empty):" 30 100 3>&1 1>&2 2>&3)
+    password_repeat=$(dialog --passwordbox "Please repeat the password:" 30 100 3>&1 1>&2 2>&3)
+
+    password_invalid_message="Passphrase empty, or not matching! "
+  done
+  set -x
+}
+
+function ask_encryption {
+  print_step_info_header
+
+  if dialog --defaultno --yesno 'Do you want to encrypt the root pool?' 30 100; then
+    v_encrypt_rpool=1
+  fi
+  set +x
+  if [[ $v_encrypt_rpool == "1" ]]; then
+    local passphrase_invalid_message=
+    local passphrase_repeat=-
+    while [[ "$v_passphrase" != "$passphrase_repeat" || ${#v_passphrase} -lt 8 ]]; do
+      v_passphrase=$(dialog --passwordbox "${passphrase_invalid_message}Please enter the passphrase for the root pool (8 chars min.):" 30 100 3>&1 1>&2 2>&3)
+      passphrase_repeat=$(dialog --passwordbox "Please repeat the passphrase:" 30 100 3>&1 1>&2 2>&3)
+
+      passphrase_invalid_message="Passphrase too short, or not matching! "
+    done
+  fi
+  set -x
+}
+
+function ask_zfs_experimental {
+  print_step_info_header
+
+  if dialog --defaultno --yesno 'Do you want to use experimental zfs module build?' 30 100; then
+    v_zfs_experimental=1
+  fi
+}
+
+function ask_hostname {
+  # shellcheck disable=SC2119
+  print_step_info_header
+
+  local hostname_invalid_message=
+
+  while [[ ! $v_hostname =~ ^[a-z][a-zA-Z_:.-]+$ ]]; do
+    v_hostname=$(dialog --inputbox "${hostname_invalid_message}Set the host name" 30 100 "$c_default_hostname" 3>&1 1>&2 2>&3)
+
+    hostname_invalid_message="Invalid host name! "
+  done
+
+  print_variables v_hostname
+}
+
+function determine_kernel_variant {
+  if dmidecode | grep -q vServer; then
+    v_kernel_variant="-virtual"
+  else
+    v_kernel_variant="-generic"
+  fi
+}
+
+function chroot_execute {
+  chroot $c_zfs_mount_dir bash -c "$1"
+}
+
+function unmount_and_export_fs {
+  # shellcheck disable=SC2119
+  print_step_info_header
+
+  for virtual_fs_dir in dev sys proc; do
+    umount --recursive --force --lazy "$c_zfs_mount_dir/$virtual_fs_dir"
+  done
+
+  local max_unmount_wait=5
+  echo -n "Waiting for virtual filesystems to unmount "
+
+  SECONDS=0
+
+  for virtual_fs_dir in dev sys proc; do
+    while mountpoint -q "$c_zfs_mount_dir/$virtual_fs_dir" && [[ $SECONDS -lt $max_unmount_wait ]]; do
+      sleep 0.5
+      echo -n .
+    done
+  done
+
+  echo
+
+  for virtual_fs_dir in dev sys proc; do
+    if mountpoint -q "$c_zfs_mount_dir/$virtual_fs_dir"; then
+      echo "Re-issuing umount for $c_zfs_mount_dir/$virtual_fs_dir"
+      umount --recursive --force --lazy "$c_zfs_mount_dir/$virtual_fs_dir"
+    fi
+  done
+
+  SECONDS=0
+  zpools_exported=99
+  echo "===========exporting zfs pools============="
+  set +e
+  while (( zpools_exported == 99 )) && (( SECONDS++ <= 60 )); do
+    
+    if zpool export -a 2> /dev/null; then
+      zpools_exported=1
+      echo "all zfs pools were succesfully exported"
+      break;
+    else
+      sleep 1
+     fi
+  done
+  set -e
+  if (( zpools_exported != 1 )); then
+    echo "failed to export zfs pools"
+    exit 1
+  fi
+}
+
+#################### MAIN ################################
+export LC_ALL=en_US.UTF-8
+export NCURSES_NO_UTF8_ACS=1
+
+check_prerequisites
+
+display_intro_banner
+
+activate_debug
+
+find_suitable_disks
+
+select_disks
+
+ask_swap_size
+
+ask_free_tail_space
+
+ask_pool_names
+
+ask_pool_tweaks
+
+ask_encryption
+
+ask_zfs_arc_max_size
+
+ask_zfs_experimental
+
+ask_root_password
+
+ask_hostname
+
+determine_kernel_variant
+
+clear
+
+echo "===========remove unused kernels in rescue system========="
+for kver in $(find /lib/modules/* -maxdepth 0 -type d | grep -v "$(uname -r)" | cut -s -d "/" -f 4); do
+  apt purge --yes "linux-headers-$kver"
+  apt purge --yes "linux-image-$kver"
+done
+
+echo "======= installing zfs on rescue system =========="
+  echo "zfs-dkms zfs-dkms/note-incompatible-licenses note true" | debconf-set-selections
+  apt-get install --yes software-properties-common
+  apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 8CF63AD3F06FC659
+  add-apt-repository 'deb http://ppa.launchpad.net/jonathonf/zfs/ubuntu focal main'
+  apt update
+  apt install --yes zfs-dkms zfsutils-linux
+  add-apt-repository -r 'deb http://ppa.launchpad.net/jonathonf/zfs/ubuntu focal main'
+  apt update
+  find /usr/local/sbin/ -type l -exec rm {} +
+  zfs --version
+
+echo "======= partitioning the disk =========="
+
+  if [[ $v_free_tail_space -eq 0 ]]; then
+    tail_space_parameter=0
+  else
+    tail_space_parameter="-${v_free_tail_space}G"
+  fi
+
+  for selected_disk in "${v_selected_disks[@]}"; do
+    wipefs --all --force "$selected_disk"
+    sgdisk -a1 -n1:24K:+1000K            -t1:EF02 "$selected_disk"
+    sgdisk -n2:0:+512M                   -t2:BF01 "$selected_disk" # Boot pool
+    sgdisk -n3:0:"$tail_space_parameter" -t3:BF01 "$selected_disk" # Root pool
+  done
+
+  udevadm settle
+
+echo "======= create zfs pools and datasets =========="
+
+  encryption_options=()
+  rpool_disks_partitions=()
+  bpool_disks_partitions=()
+
+  if [[ $v_encrypt_rpool == "1" ]]; then
+    encryption_options=(-O "encryption=aes-256-gcm" -O "keylocation=prompt" -O "keyformat=passphrase")
+  fi
+
+  for selected_disk in "${v_selected_disks[@]}"; do
+    rpool_disks_partitions+=("${selected_disk}-part3")
+    bpool_disks_partitions+=("${selected_disk}-part2")
+  done
+
+  if [[ ${#v_selected_disks[@]} -gt 1 ]]; then
+    pools_mirror_option=mirror
+  else
+    pools_mirror_option=
+  fi
+
+# shellcheck disable=SC2086
+zpool create \
+  $v_bpool_tweaks -O canmount=off -O devices=off \
+  -o cachefile=/etc/zfs/zpool.cache \
+  -O mountpoint=/boot -R $c_zfs_mount_dir -f \
+  $v_bpool_name $pools_mirror_option "${bpool_disks_partitions[@]}"
+
+# shellcheck disable=SC2086
+echo -n "$v_passphrase" | zpool create \
+  $v_rpool_tweaks \
+  -o cachefile=/etc/zfs/zpool.cache \
+  "${encryption_options[@]}" \
+  -O mountpoint=/ -R $c_zfs_mount_dir -f \
+  $v_rpool_name $pools_mirror_option "${rpool_disks_partitions[@]}"
+
+zfs create -o canmount=off -o mountpoint=none "$v_rpool_name/ROOT"
+zfs create -o canmount=off -o mountpoint=none "$v_bpool_name/BOOT"
+
+zfs create -o canmount=noauto -o mountpoint=/ "$v_rpool_name/ROOT/ubuntu"
+zfs mount "$v_rpool_name/ROOT/ubuntu"
+
+zfs create -o canmount=noauto -o mountpoint=/boot "$v_bpool_name/BOOT/ubuntu"
+zfs mount "$v_bpool_name/BOOT/ubuntu"
+
+zfs create                                 "$v_rpool_name/home"
+zfs create -o mountpoint=/root             "$v_rpool_name/home/root"
+zfs create -o canmount=off                 "$v_rpool_name/var"
+zfs create -o canmount=off                 "$v_rpool_name/var/lib"
+zfs create                                 "$v_rpool_name/var/log"
+zfs create                                 "$v_rpool_name/var/spool"
+
+zfs create -o com.sun:auto-snapshot=false  "$v_rpool_name/var/cache"
+zfs create -o com.sun:auto-snapshot=false  "$v_rpool_name/var/tmp"
+chmod 1777 "$c_zfs_mount_dir/var/tmp"
+
+zfs create                                 "$v_rpool_name/srv"
+
+zfs create -o canmount=off                 "$v_rpool_name/usr"
+zfs create                                 "$v_rpool_name/usr/local"
+
+zfs create                                 "$v_rpool_name/var/mail"
+
+zfs create -o com.sun:auto-snapshot=false -o canmount=on -o mountpoint=/tmp "$v_rpool_name/tmp"
+chmod 1777 "$c_zfs_mount_dir/tmp"
+
+if [[ $v_swap_size -gt 0 ]]; then
+  zfs create \
+    -V "${v_swap_size}G" -b "$(getconf PAGESIZE)" \
+    -o compression=zle -o logbias=throughput -o sync=always -o primarycache=metadata -o secondarycache=none -o com.sun:auto-snapshot=false \
+    "$v_rpool_name/swap"
+
+  udevadm settle
+
+  mkswap -f "/dev/zvol/$v_rpool_name/swap"
+fi
+
+echo "======= setting up initial system packages =========="
+debootstrap --arch=amd64 focal "$c_zfs_mount_dir" "$c_deb_packages_repo"
+
+zfs set devices=off "$v_rpool_name"
+
+echo "======= setting up the network =========="
+
+echo "$v_hostname" > $c_zfs_mount_dir/etc/hostname
+
+cat > "$c_zfs_mount_dir/etc/hosts" <<CONF
+127.0.1.1 ${v_hostname}
+127.0.0.1 localhost
+
+# The following lines are desirable for IPv6 capable hosts
+::1 ip6-localhost ip6-loopback
+fe00::0 ip6-localnet
+ff00::0 ip6-mcastprefix
+ff02::1 ip6-allnodes
+ff02::2 ip6-allrouters
+ff02::3 ip6-allhosts
+CONF
+
+ip6addr_prefix=$(ip -6 a s | grep -E "inet6.+global" | sed -nE 's/.+inet6\s(([0-9a-z]{1,4}:){4,4}).+/\1/p')
+
+cat <<CONF > /mnt/etc/systemd/network/10-eth0.network
+[Match]
+Name=eth0
+
+[Network]
+DHCP=ipv4
+Address=${ip6addr_prefix}:1/64
+Gateway=fe80::1
+CONF
+
+chroot_execute "systemctl enable systemd-networkd.service"
+
+
+mkdir -p "$c_zfs_mount_dir/etc/cloud/cloud.cfg.d/"
+cat > "$c_zfs_mount_dir/etc/cloud/cloud.cfg.d/99-disable-network-config.cfg" <<CONF
+network:
+  config: disabled
+CONF
+
+rm -rf $c_zfs_mount_dir/etc/network/interfaces.d/50-cloud-init.cfg
+
+cp /etc/resolv.conf $c_zfs_mount_dir/etc/resolv.conf
+
+echo "======= preparing the jail for chroot =========="
+for virtual_fs_dir in proc sys dev; do
+  mount --rbind "/$virtual_fs_dir" "$c_zfs_mount_dir/$virtual_fs_dir"
+done
+
+echo "======= setting apt repos =========="
+cat > "$c_zfs_mount_dir/etc/apt/sources.list" <<CONF
+deb [arch=i386,amd64] $c_deb_packages_repo focal main restricted
+deb [arch=i386,amd64] $c_deb_packages_repo focal-updates main restricted
+deb [arch=i386,amd64] $c_deb_packages_repo focal-backports main restricted
+deb [arch=i386,amd64] $c_deb_packages_repo focal universe
+deb [arch=i386,amd64] $c_deb_security_repo focal-security main restricted
+CONF
+
+chroot_execute "apt update"
+
+echo "======= setting locale, console and language =========="
+chroot_execute "apt install --yes -qq locales debconf-i18n apt-utils keyboard-configuration console-setup"
+sed -i 's/# en_US.UTF-8/en_US.UTF-8/' "$c_zfs_mount_dir/etc/locale.gen"
+sed -i 's/# fr_FR.UTF-8/fr_FR.UTF-8/' "$c_zfs_mount_dir/etc/locale.gen"
+sed -i 's/# fr_FR.UTF-8/fr_FR.UTF-8/' "$c_zfs_mount_dir/etc/locale.gen"
+sed -i 's/# de_AT.UTF-8/de_AT.UTF-8/' "$c_zfs_mount_dir/etc/locale.gen"
+sed -i 's/# de_DE.UTF-8/de_DE.UTF-8/' "$c_zfs_mount_dir/etc/locale.gen"
+
+chroot_execute 'cat <<CONF | debconf-set-selections
+locales locales/default_environment_locale      select  en_US.UTF-8
+keyboard-configuration  keyboard-configuration/store_defaults_in_debconf_db     boolean true
+keyboard-configuration  keyboard-configuration/variant  select  German
+keyboard-configuration  keyboard-configuration/unsupported_layout       boolean true
+keyboard-configuration  keyboard-configuration/modelcode        string  pc105
+keyboard-configuration  keyboard-configuration/unsupported_config_layout        boolean true
+keyboard-configuration  keyboard-configuration/layout   select  German
+keyboard-configuration  keyboard-configuration/layoutcode       string  de
+keyboard-configuration  keyboard-configuration/optionscode      string
+keyboard-configuration  keyboard-configuration/toggle   select  No toggling
+keyboard-configuration  keyboard-configuration/xkb-keymap       select  de
+keyboard-configuration  keyboard-configuration/switch   select  No temporary switch
+keyboard-configuration  keyboard-configuration/unsupported_config_options       boolean true
+keyboard-configuration  keyboard-configuration/ctrl_alt_bksp    boolean false
+keyboard-configuration  keyboard-configuration/variantcode      string
+keyboard-configuration  keyboard-configuration/model    select  Generic 105-key PC (intl.)
+keyboard-configuration  keyboard-configuration/altgr    select  The default for the keyboard layout
+keyboard-configuration  keyboard-configuration/compose  select  No compose key
+keyboard-configuration  keyboard-configuration/unsupported_options      boolean true
+console-setup   console-setup/fontsize-fb47     select  8x16
+console-setup   console-setup/store_defaults_in_debconf_db      boolean true
+console-setup   console-setup/codeset47 select  # Latin1 and Latin5 - western Europe and Turkic languages
+console-setup   console-setup/fontface47        select  Fixed
+console-setup   console-setup/fontsize  string  8x16
+console-setup   console-setup/charmap47 select  UTF-8
+console-setup   console-setup/fontsize-text47   select  8x16
+console-setup   console-setup/codesetcode       string  Lat15
+tzdata tzdata/Areas select Europe
+tzdata tzdata/Zones/Europe select Vienna
+grub-pc grub-pc/install_devices_empty   boolean true
+CONF'
+
+chroot_execute "dpkg-reconfigure locales -f noninteractive"
+echo -e "LC_ALL=en_US.UTF-8\nLANG=en_US.UTF-8\n" >> "$c_zfs_mount_dir/etc/environment"
+chroot_execute "dpkg-reconfigure keyboard-configuration -f noninteractive"
+chroot_execute "dpkg-reconfigure console-setup -f noninteractive"
+chroot_execute "setupcon"
+
+chroot_execute "rm -f /etc/localtime /etc/timezone"
+chroot_execute "dpkg-reconfigure tzdata -f noninteractive "
+
+echo "======= installing latest kernel============="
+chroot_execute "DEBIAN_FRONTEND=noninteractive apt install --yes linux-headers${v_kernel_variant}-hwe-18.04 linux-image${v_kernel_variant}-hwe-18.04"
+if [[ $v_kernel_variant == "-virtual" ]]; then
+  # linux-image-extra is only available for virtual hosts
+  chroot_execute "DEBIAN_FRONTEND=noninteractive apt install --yes linux-image-extra-virtual-hwe-20.04"
+fi
+
+
+echo "======= installing aux packages =========="
+chroot_execute "apt install --yes man-db wget curl software-properties-common nano htop gnupg"
+chroot_execute "systemctl disable thermald"
+
+echo "======= installing zfs packages =========="
+chroot_execute 'echo "zfs-dkms zfs-dkms/note-incompatible-licenses note true" | debconf-set-selections'
+
+if [[ $v_zfs_experimental == "1" ]]; then
+  chroot_execute "wget -O - https://terem42.github.io/zfs-debian/apt_pub.gpg | apt-key add -"
+  chroot_execute "add-apt-repository 'deb https://terem42.github.io/zfs-debian/public zfs-debian-experimental main'"
+  chroot_execute "apt update"
+  chroot_execute "apt install -t zfs-debian-experimental --yes zfs-initramfs zfs-dkms zfsutils-linux"
+else
+  chroot_execute "add-apt-repository --yes ppa:jonathonf/zfs"
+  chroot_execute "apt install --yes zfs-initramfs zfs-dkms zfsutils-linux"
+fi
+
+echo "======= installing OpenSSH and network tooling =========="
+chroot_execute "apt install --yes openssh-server net-tools"
+
+echo "======= setup OpenSSH  =========="
+mkdir -p "$c_zfs_mount_dir/root/.ssh/"
+cp /root/.ssh/authorized_keys "$c_zfs_mount_dir/root/.ssh/authorized_keys"
+sed -i 's/#PasswordAuthentication yes/PasswordAuthentication no/g' "$c_zfs_mount_dir/etc/ssh/sshd_config"
+sed -i 's/#PubkeyAuthentication yes/PubkeyAuthentication yes/g' "$c_zfs_mount_dir/etc/ssh/sshd_config"
+chroot_execute "rm /etc/ssh/ssh_host_*"
+chroot_execute "dpkg-reconfigure openssh-server -f noninteractive"
+
+echo "======= set root password =========="
+chroot_execute "echo root:$(printf "%q" "$v_root_password") | chpasswd"
+
+echo "======= setting up zfs cache =========="
+cp /etc/zfs/zpool.cache /mnt/etc/zfs/zpool.cache
+
+echo "========setting up zfs module parameters========"
+chroot_execute "echo options zfs zfs_arc_max=$((v_zfs_arc_max_mb * 1024 * 1024)) >> /etc/modprobe.d/zfs.conf"
+
+echo "======= setting up grub =========="
+chroot_execute "echo 'grub-pc grub-pc/install_devices_empty   boolean true' | debconf-set-selections"
+chroot_execute "DEBIAN_FRONTEND=noninteractive apt install --yes grub-pc"
+chroot_execute "grub-install ${v_selected_disks[0]}"
+
+chroot_execute "sed -i 's/#GRUB_TERMINAL=console/GRUB_TERMINAL=console/g' /etc/default/grub"
+chroot_execute "sed -i 's|GRUB_CMDLINE_LINUX_DEFAULT=.*|GRUB_CMDLINE_LINUX_DEFAULT=\"net.ifnames=0\"|' /etc/default/grub"
+chroot_execute "sed -i 's|GRUB_CMDLINE_LINUX=\"\"|GRUB_CMDLINE_LINUX=\"root=ZFS=rpool/ROOT/ubuntu\"|g' /etc/default/grub"
+
+chroot_execute "sed -i 's/quiet//g' /etc/default/grub"
+chroot_execute "sed -i 's/splash//g' /etc/default/grub"
+chroot_execute "echo 'GRUB_DISABLE_OS_PROBER=true'   >> /etc/default/grub"
+
+for ((i = 1; i < ${#v_selected_disks[@]}; i++)); do
+  dd if="${v_selected_disks[0]}-part1" of="${v_selected_disks[i]}-part1"
+done
+
+if [[ $v_encrypt_rpool == "1" ]]; then
+  echo "=========set up dropbear=============="
+  chroot_execute "apt install --yes dropbear-initramfs"
+
+  cp /root/.ssh/authorized_keys "$c_zfs_mount_dir/etc/dropbear-initramfs/authorized_keys"
+
+  cp "$c_zfs_mount_dir/etc/ssh/ssh_host_rsa_key" "$c_zfs_mount_dir/etc/ssh/ssh_host_rsa_key_temp"
+  chroot_execute "ssh-keygen -p -i -m pem -N '' -f /etc/ssh/ssh_host_rsa_key_temp"
+  chroot_execute "/usr/lib/dropbear/dropbearconvert openssh dropbear /etc/ssh/ssh_host_rsa_key_temp /etc/dropbear-initramfs/dropbear_rsa_host_key"
+  rm -rf "$c_zfs_mount_dir/etc/ssh/ssh_host_rsa_key_temp"
+
+  cp "$c_zfs_mount_dir/etc/ssh/ssh_host_ecdsa_key" "$c_zfs_mount_dir/etc/ssh/ssh_host_ecdsa_key_temp"
+  chroot_execute "ssh-keygen -p -i -m pem -N '' -f /etc/ssh/ssh_host_ecdsa_key_temp"
+  chroot_execute "/usr/lib/dropbear/dropbearconvert openssh dropbear /etc/ssh/ssh_host_ecdsa_key_temp /etc/dropbear-initramfs/dropbear_ecdsa_host_key"
+  chroot_execute "rm -rf /etc/ssh/ssh_host_ecdsa_key_temp"
+  rm -rf "$c_zfs_mount_dir/etc/ssh/ssh_host_ecdsa_key_temp"
+
+  rm -rf "$c_zfs_mount_dir/etc/dropbear-initramfs/dropbear_dss_host_key"
+
+  cd "$c_zfs_mount_dir/root"
+  wget http://ftp.de.debian.org/debian/pool/main/libt/libtommath/libtommath1_1.1.0-3_amd64.deb
+  wget http://ftp.de.debian.org/debian/pool/main/d/dropbear/dropbear-bin_2018.76-5_amd64.deb
+  wget http://ftp.de.debian.org/debian/pool/main/d/dropbear/dropbear-initramfs_2018.76-5_all.deb
+
+  chroot_execute "dpkg -i /root/libtommath1_1.1.0-3_amd64.deb"
+  chroot_execute "dpkg -i /root/dropbear-bin_2018.76-5_amd64.deb"
+  chroot_execute "dpkg -i /root/dropbear-initramfs_2018.76-5_all.deb"
+
+  rm $c_zfs_mount_dir/root/*.deb
+  cd /root
+fi
+
+echo "============setup root prompt============"
+cat > "$c_zfs_mount_dir/root/.bashrc" <<CONF
+export PS1='\[\033[01;31m\]\u\[\033[01;33m\]@\[\033[01;32m\]\h \[\033[01;33m\]\w \[\033[01;35m\]\$ \[\033[00m\]'
+umask 022
+export LS_OPTIONS='--color=auto -h'
+eval "\$(dircolors)"
+CONF
+
+echo "========running packages upgrade==========="
+chroot_execute "apt upgrade --yes"
+
+echo "===========add static route to initramfs via hook to add default routes due to Ubuntu initramfs DHCP bug ========="
+mkdir -p "$c_zfs_mount_dir/usr/share/initramfs-tools/scripts/init-premount"
+cat > "$c_zfs_mount_dir/usr/share/initramfs-tools/scripts/init-premount/static-route" <<'CONF'
+#!/bin/sh
+PREREQ=""
+prereqs()
+{
+    echo "$PREREQ"
+}
+
+case $1 in
+prereqs)
+    prereqs
+    exit 0
+    ;;
+esac
+
+. /scripts/functions
+# Begin real processing below this line
+
+configure_networking
+
+ip route add 172.31.1.1/255.255.255.255 dev ens3
+ip route add default via 172.31.1.1 dev ens3
+CONF
+
+chmod 755 "$c_zfs_mount_dir/usr/share/initramfs-tools/scripts/init-premount/static-route"
+
+echo "======= update initramfs =========="
+chroot_execute "update-initramfs -u -k all"
+
+echo "======= update grub =========="
+chroot_execute "update-grub"
+
+echo "======= setting up zed =========="
+
+chroot_execute "zfs set canmount=noauto rpool"
+
+echo "======= setting mountpoints =========="
+chroot_execute "zfs set mountpoint=legacy $v_bpool_name/BOOT/ubuntu"
+chroot_execute "echo $v_bpool_name/BOOT/ubuntu /boot zfs nodev,relatime,x-systemd.requires=zfs-mount.service,x-systemd.device-timeout=10 0 0 > /etc/fstab"
+
+chroot_execute "zfs set mountpoint=legacy $v_rpool_name/var/log"
+chroot_execute "echo $v_rpool_name/var/log /var/log zfs nodev,relatime 0 0 >> /etc/fstab"
+chroot_execute "zfs set mountpoint=legacy $v_rpool_name/var/spool"
+chroot_execute "echo $v_rpool_name/var/spool /var/spool zfs nodev,relatime 0 0 >> /etc/fstab"
+chroot_execute "zfs set mountpoint=legacy $v_rpool_name/var/tmp"
+chroot_execute "echo $v_rpool_name/var/tmp /var/tmp zfs nodev,relatime 0 0 >> /etc/fstab"
+chroot_execute "zfs set mountpoint=legacy $v_rpool_name/tmp"
+chroot_execute "echo $v_rpool_name/tmp /tmp zfs nodev,relatime 0 0 >> /etc/fstab"
+
+echo "========= add swap, if defined"
+if [[ $v_swap_size -gt 0 ]]; then
+  chroot_execute "echo /dev/zvol/$v_rpool_name/swap none swap discard 0 0 >> /etc/fstab"
+fi
+
+chroot_execute "echo RESUME=none > /etc/initramfs-tools/conf.d/resume"
+
+echo "======= unmounting filesystems and zfs pools =========="
+unmount_and_export_fs
+
+echo "======== setup complete, rebooting ==============="
+reboot