deb pkg location update

ubuntu20: install zfs from bullseye-backports (on recovery)

.github/workflows/shellcheck.yml

@@ -1,24 +1,11 @@
 name: shellcheck
 
-on:
-  push:
-    branches: [master, develop]
-  pull_request:
-    branches: [master]
+on: push
 
 jobs:
-  Shellcheck:
-    name: Shellcheck
+  test:
     runs-on: ubuntu-latest
-
     steps:
-      - name: Code checkout
-        uses: actions/checkout@v2
-
-      - name: Check scripts with Shellcheck
-        uses: essentialkaos/shellcheck-action@v1
-        with:
-          files: hetzner-debian10-zfs-setup.sh hetzner-debian11-zfs-setup.sh hetzner-ubuntu18-zfs-setup.sh hetzner-ubuntu20-zfs-setup.sh 
-          severity: error
-          format: gcc
-          shell: bash
+    - uses: actions/checkout@v2
+    - name: Run shellcheck
+      run: ci/run_shellcheck.sh

README.md

@@ -2,7 +2,7 @@
 
 [![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/>
+Scripts to install Debian 11, 10 or Ubuntu 18 LTS, 20 LTS, 22 LTS with ZFS root on Hetzner root servers (virtual and dedicated).<br/>
 __WARNING:__ all data on the disk will be destroyed.
 
 ## How to use:
@@ -12,28 +12,34 @@ __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 10 minimal setup with SSH server
+
+````bash
+wget -qO- https://raw.githubusercontent.com/terem42/zfs-hetzner-vm/master/hetzner-debian10-zfs-setup.sh | bash -
+````
+
 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 18.04 LTS minimal setup with SSH server
+
+````bash
+wget -qO- https://raw.githubusercontent.com/terem42/zfs-hetzner-vm/master/hetzner-ubuntu18-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
+Ubuntu 22 LTS minimal setup with SSH server
 
 ````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/terem42/zfs-hetzner-vm/master/hetzner-ubuntu18-zfs-setup.sh | bash -
+wget -qO- https://raw.githubusercontent.com/terem42/zfs-hetzner-vm/master/hetzner-ubuntu22-zfs-setup.sh | bash -
 ````
 
 Answer script questions about desired hostname and ZFS ARC cache size.
@@ -49,3 +55,5 @@ To reattach, type `screen -r zfs`
 
 Upon succesfull run, the script will reboot system, and you will be able to login into it, using the same SSH key you have used within rescue console
 
+Please note that the drives you intend to format can not be in use,
+you can execute `mdadm --stop --scan` before running the script to halt default software raid operations.

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

@@ -62,7 +62,9 @@ function print_step_info_header {
 ###############################################################################
 # ${FUNCNAME[1]}"
 
-  [[ "${1:-}" != "" ]] && echo -n " $1" || true
+  if [[ "${1:-}" != "" ]]; then
+    echo -n " $1" 
+  fi
 
   echo "
 ###############################################################################
@@ -141,13 +143,13 @@ function initial_load_debian_zed_cache {
 
   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
+    while (( SECONDS++ <= 300 )); 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
@@ -379,7 +381,7 @@ function ask_hostname {
 
   local hostname_invalid_message=
 
-  while [[ ! $v_hostname =~ ^[a-z][a-zA-Z_:.-]+$ ]]; do
+  while [[ ! $v_hostname =~ ^[a-z][a-zA-Z0-9_:.-]+$ ]]; 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! "
@@ -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
-    zpool export -a 2> /dev/null
-    if [[ $? == 0 ]]; then
+  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;
@@ -493,13 +494,7 @@ 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 {} +
+  echo "y" | zfs
   zfs --version
 
 echo "======= partitioning the disk =========="
@@ -513,7 +508,7 @@ echo "======= partitioning the disk =========="
   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 -n2:0:+2G                   -t2:BF01 "$selected_disk" # Boot pool
     sgdisk -n3:0:"$tail_space_parameter" -t3:BF01 "$selected_disk" # Root pool
   done
 
@@ -540,14 +535,16 @@ echo "======= create zfs pools and datasets =========="
     pools_mirror_option=
   fi
 
+# shellcheck disable=SC2086
 zpool create \
   $v_bpool_tweaks -O canmount=off -O devices=off \
-  -o cachefile=/etc/zfs/zpool.cache \
+  -o cachefile=/etc/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 \
+  -o cachefile=/etc/zpool.cache \
   $v_rpool_tweaks \
   "${encryption_options[@]}" \
   -O mountpoint=/ -R $c_zfs_mount_dir -f \
@@ -628,6 +625,7 @@ Address=${ip6addr_prefix}:1/64
 Gateway=fe80::1
 CONF
 chroot_execute "systemctl enable systemd-networkd.service"
+chroot_execute "systemctl enable systemd-resolved.service"
 
 
 cp /etc/resolv.conf $c_zfs_mount_dir/etc/resolv.conf
@@ -715,6 +713,12 @@ if [[ $v_zfs_experimental == "1" ]]; then
 else
   chroot_execute "apt install --yes -t buster-backports zfs-initramfs zfs-dkms zfsutils-linux"
 fi
+chroot_execute 'cat << DKMS > /etc/dkms/zfs.conf
+# override for /usr/src/zfs-*/dkms.conf:
+# always rebuild initrd when zfs module has been changed
+# (either by a ZFS update or a new kernel version)
+REMAKE_INITRD="yes"
+DKMS'
 
 echo "======= installing OpenSSH and network tooling =========="
 chroot_execute "apt install --yes openssh-server net-tools"
@@ -731,7 +735,7 @@ 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
+cp /etc/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"
@@ -807,10 +811,22 @@ esac
 
 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
+ip route add 172.31.1.1/255.255.255.255 dev eth0
+ip route add default via 172.31.1.1 dev eth0
 CONF
 
+cat > "$c_zfs_mount_dir/etc/network/interfaces" <<'CONF'
+auto lo
+iface lo inet loopback
+iface lo inet6 loopback
+
+auto eth0
+iface eth0 inet dhcp
+iface eth0 inet6 dhcp
+CONF
+
+chmod 755 "$c_zfs_mount_dir/etc/network/interfaces"
+
 echo "======= update initramfs =========="
 chroot_execute "update-initramfs -u -k all"
 
@@ -838,7 +854,9 @@ 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

@@ -35,8 +35,8 @@ 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_deb_packages_repo=http://deb.debian.org/debian
+c_deb_security_repo=http://deb.debian.org/debian-security
 
 c_default_zfs_arc_max_mb=250
 c_default_bpool_tweaks="-o ashift=12 -O compression=lz4"
@@ -62,7 +62,10 @@ function print_step_info_header {
 ###############################################################################
 # ${FUNCNAME[1]}"
 
-  [[ "${1:-}" != "" ]] && echo -n " $1" || true
+  if [[ "${1:-}" != "" ]]; then
+    echo -n " $1" 
+  fi
+
 
   echo "
 ###############################################################################
@@ -141,13 +144,13 @@ function initial_load_debian_zed_cache {
 
   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
@@ -379,7 +382,7 @@ function ask_hostname {
 
   local hostname_invalid_message=
 
-  while [[ ! $v_hostname =~ ^[a-z][a-zA-Z_:.-]+$ ]]; do
+  while [[ ! $v_hostname =~ ^[a-z][a-zA-Z0-9_:.-]+$ ]]; 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! "
@@ -431,9 +434,8 @@ function unmount_and_export_fs {
   zpools_exported=99
   echo "===========exporting zfs pools============="
   set +e
-  while (( zpools_exported == 99 )) && (( SECONDS++ <= 60 )); do
-    zpool export -a 2> /dev/null
-    if [[ $? == 0 ]]; then
+  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;
@@ -493,13 +495,7 @@ 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 {} +
+  echo "y" | zfs
   zfs --version
 
 echo "======= partitioning the disk =========="
@@ -513,7 +509,7 @@ echo "======= partitioning the disk =========="
   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 -n2:0:+2G                   -t2:BF01 "$selected_disk" # Boot pool
     sgdisk -n3:0:"$tail_space_parameter" -t3:BF01 "$selected_disk" # Root pool
   done
 
@@ -540,15 +536,17 @@ 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 cachefile=/etc/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 \
   $v_rpool_tweaks \
-  -o cachefile=/etc/zfs/zpool.cache \
+  -o cachefile=/etc/zpool.cache \
   "${encryption_options[@]}" \
   -O mountpoint=/ -R $c_zfs_mount_dir -f \
   $v_rpool_name $pools_mirror_option "${rpool_disks_partitions[@]}"
@@ -628,6 +626,7 @@ Address=${ip6addr_prefix}:1/64
 Gateway=fe80::1
 CONF
 chroot_execute "systemctl enable systemd-networkd.service"
+chroot_execute "systemctl enable systemd-resolved.service"
 
 
 cp /etc/resolv.conf $c_zfs_mount_dir/etc/resolv.conf
@@ -713,8 +712,14 @@ if [[ $v_zfs_experimental == "1" ]]; then
   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"
+  chroot_execute "apt install -t bullseye-backports --yes zfs-initramfs zfs-dkms zfsutils-linux"
 fi
+chroot_execute 'cat << DKMS > /etc/dkms/zfs.conf
+# override for /usr/src/zfs-*/dkms.conf:
+# always rebuild initrd when zfs module has been changed
+# (either by a ZFS update or a new kernel version)
+REMAKE_INITRD="yes"
+DKMS'
 
 echo "======= installing OpenSSH and network tooling =========="
 chroot_execute "apt install --yes openssh-server net-tools"
@@ -732,7 +737,7 @@ 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
+cp /etc/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"
@@ -809,12 +814,14 @@ esac
 
 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
+ip route add 172.31.1.1/255.255.255.255 dev eth0
+ip route add default via 172.31.1.1 dev eth0
 CONF
 
 chmod 755 "$c_zfs_mount_dir/usr/share/initramfs-tools/scripts/init-premount/static-route"
 
+chmod 755 "$c_zfs_mount_dir/etc/network/interfaces"
+
 echo "======= update initramfs =========="
 chroot_execute "update-initramfs -u -k all"
 
@@ -842,7 +849,10 @@ 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-ubuntu18-zfs-setup.sh

@@ -62,7 +62,9 @@ function print_step_info_header {
 ###############################################################################
 # ${FUNCNAME[1]}"
 
-  [[ "${1:-}" != "" ]] && echo -n " $1" || true
+  if [[ "${1:-}" != "" ]]; then
+    echo -n " $1" 
+  fi
 
   echo "
 ###############################################################################
@@ -344,7 +346,7 @@ function ask_hostname {
 
   local hostname_invalid_message=
 
-  while [[ ! $v_hostname =~ ^[a-z][a-zA-Z_:.-]+$ ]]; do
+  while [[ ! $v_hostname =~ ^[a-z][a-zA-Z0-9_:.-]+$ ]]; 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! "
@@ -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;
@@ -460,13 +462,7 @@ 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 {} +
+  echo "y" | zfs
   zfs --version
 
 echo "======= partitioning the disk =========="
@@ -480,7 +476,7 @@ echo "======= partitioning the disk =========="
   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 -n2:0:+2G                   -t2:BF01 "$selected_disk" # Boot pool
     sgdisk -n3:0:"$tail_space_parameter" -t3:BF01 "$selected_disk" # Root pool
   done
 
@@ -507,15 +503,17 @@ 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 cachefile=/etc/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 \
   $v_rpool_tweaks \
-  -o cachefile=/etc/zfs/zpool.cache \
+  -o cachefile=/etc/zpool.cache \
   "${encryption_options[@]}" \
   -O mountpoint=/ -R $c_zfs_mount_dir -f \
   $v_rpool_name $pools_mirror_option "${rpool_disks_partitions[@]}"
@@ -596,6 +594,7 @@ Gateway=fe80::1
 CONF
 
 chroot_execute "systemctl enable systemd-networkd.service"
+chroot_execute "systemctl enable systemd-resolved.service"
 
 
 mkdir -p "$c_zfs_mount_dir/etc/cloud/cloud.cfg.d/"
@@ -697,6 +696,12 @@ else
   chroot_execute "add-apt-repository --yes ppa:jonathonf/zfs"
   chroot_execute "apt install --yes zfs-initramfs zfs-dkms zfsutils-linux"
 fi
+chroot_execute 'cat << DKMS > /etc/dkms/zfs.conf
+# override for /usr/src/zfs-*/dkms.conf:
+# always rebuild initrd when zfs module has been changed
+# (either by a ZFS update or a new kernel version)
+REMAKE_INITRD="yes"
+DKMS'
 
 echo "======= installing OpenSSH and network tooling =========="
 chroot_execute "apt install --yes openssh-server net-tools"
@@ -713,7 +718,7 @@ 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
+cp /etc/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"
@@ -830,7 +835,10 @@ 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

@@ -62,7 +62,9 @@ function print_step_info_header {
 ###############################################################################
 # ${FUNCNAME[1]}"
 
-  [[ "${1:-}" != "" ]] && echo -n " $1" || true
+  if [[ "${1:-}" != "" ]]; then
+    echo -n " $1" 
+  fi
 
   echo "
 ###############################################################################
@@ -344,7 +346,7 @@ function ask_hostname {
 
   local hostname_invalid_message=
 
-  while [[ ! $v_hostname =~ ^[a-z][a-zA-Z_:.-]+$ ]]; do
+  while [[ ! $v_hostname =~ ^[a-z][a-zA-Z0-9_:.-]+$ ]]; 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! "
@@ -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;
@@ -460,13 +462,7 @@ 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 {} +
+  echo "y" | zfs
   zfs --version
 
 echo "======= partitioning the disk =========="
@@ -480,7 +476,7 @@ echo "======= partitioning the disk =========="
   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 -n2:0:+2G                   -t2:BF01 "$selected_disk" # Boot pool
     sgdisk -n3:0:"$tail_space_parameter" -t3:BF01 "$selected_disk" # Root pool
   done
 
@@ -507,15 +503,17 @@ 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 cachefile=/etc/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 \
   $v_rpool_tweaks \
-  -o cachefile=/etc/zfs/zpool.cache \
+  -o cachefile=/etc/zpool.cache \
   "${encryption_options[@]}" \
   -O mountpoint=/ -R $c_zfs_mount_dir -f \
   $v_rpool_name $pools_mirror_option "${rpool_disks_partitions[@]}"
@@ -596,6 +594,7 @@ Gateway=fe80::1
 CONF
 
 chroot_execute "systemctl enable systemd-networkd.service"
+chroot_execute "systemctl enable systemd-resolved.service"
 
 
 mkdir -p "$c_zfs_mount_dir/etc/cloud/cloud.cfg.d/"
@@ -675,10 +674,10 @@ 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"
+chroot_execute "DEBIAN_FRONTEND=noninteractive apt install --yes linux-headers${v_kernel_variant} linux-image${v_kernel_variant}"
 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"
+  chroot_execute "DEBIAN_FRONTEND=noninteractive apt install --yes linux-image-extra-virtual"
 fi
 
 
@@ -698,6 +697,12 @@ else
   chroot_execute "add-apt-repository --yes ppa:jonathonf/zfs"
   chroot_execute "apt install --yes zfs-initramfs zfs-dkms zfsutils-linux"
 fi
+chroot_execute 'cat << DKMS > /etc/dkms/zfs.conf
+# override for /usr/src/zfs-*/dkms.conf:
+# always rebuild initrd when zfs module has been changed
+# (either by a ZFS update or a new kernel version)
+REMAKE_INITRD="yes"
+DKMS'
 
 echo "======= installing OpenSSH and network tooling =========="
 chroot_execute "apt install --yes openssh-server net-tools"
@@ -714,7 +719,7 @@ 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
+cp /etc/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"
@@ -756,13 +761,13 @@ if [[ $v_encrypt_rpool == "1" ]]; then
   rm -rf "$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
+  wget http://ftp.de.debian.org/debian/pool/main/libt/libtommath/libtommath1_1.2.0-6_amd64.deb
+  wget http://ftp.de.debian.org/debian/pool/main/d/dropbear/dropbear-bin_2020.81-3_amd64.deb
+  wget http://ftp.de.debian.org/debian/pool/main/d/dropbear/dropbear-initramfs_2020.81-3_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"
+  chroot_execute "dpkg -i /root/libtommath1_1.2.0-6_amd64.deb"
+  chroot_execute "dpkg -i /root/dropbear-bin_2020.81-3_amd64.deb"
+  chroot_execute "dpkg -i /root/dropbear-initramfs_2020.81-3_all.deb"
 
   rm $c_zfs_mount_dir/root/*.deb
   cd /root
@@ -831,7 +836,10 @@ 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-ubuntu22-zfs-setup.sh

@@ -0,0 +1,853 @@
+#!/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 [[ ! $v_hostname =~ ^[a-z][a-zA-Z0-9_:.-]+$ ]]; 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 =========="
+  apt-get install --yes software-properties-common
+  gpg --keyid-format long --keyserver hkp://keyserver.ubuntu.com --recv-keys 0x871920D1991BC93C
+  gpg --export 871920D1991BC93C > /usr/share/keyrings/ubuntu-archive-keyring.gpg
+  apt --only-upgrade -t bullseye-backports install debootstrap
+  echo "zfs-dkms zfs-dkms/note-incompatible-licenses note true" | debconf-set-selections
+  echo "y" | zfs
+  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 "$selected_disk"
+    sgdisk -n2:0:+2G                   -t2:BF01 "$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/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 \
+  $v_rpool_tweaks \
+  -o cachefile=/etc/zpool.cache \
+  "${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/$v_rpool_name/swap"
+fi
+
+echo "======= setting up initial system packages =========="
+debootstrap --arch=amd64 jammy "$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=${ip6addr_prefix}:1/64
+Gateway=fe80::1
+CONF
+
+chroot_execute "systemctl enable systemd-networkd.service"
+chroot_execute "systemctl enable systemd-resolved.service"
+
+
+mkdir -p "$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 jammy main restricted
+deb [arch=i386,amd64] $c_deb_packages_repo jammy-updates main restricted
+deb [arch=i386,amd64] $c_deb_packages_repo jammy-backports main restricted
+deb [arch=i386,amd64] $c_deb_packages_repo jammy universe
+deb [arch=i386,amd64] $c_deb_security_repo jammy-security main restricted
+CONF
+
+chroot_execute "apt update"
+
+echo "======= setting locale, console and language =========="
+chroot_execute "apt --yes --fix-broken install"
+chroot_execute "apt install --yes -qq locales debconf-i18n apt-utils keyboard-configuration console-setup"
+sed -i 's/# en_US.UTF-8/en_US.UTF-8/' "$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} linux-image${v_kernel_variant}"
+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"
+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 [[ $v_zfs_experimental == "1" ]]; then
+  chroot_execute "wget -O - https://terem42.github.io/zfs-debian/apt_pub.gpg | apt-key add -"
+  chroot_execute "add-apt-repository 'deb https://terem42.github.io/zfs-debian/public zfs-debian-experimental main'"
+  chroot_execute "apt update"
+  chroot_execute "apt install -t zfs-debian-experimental --yes zfs-initramfs zfs-dkms zfsutils-linux"
+else
+  chroot_execute "add-apt-repository --yes ppa:jonathonf/zfs"
+  chroot_execute "apt install --yes zfs-initramfs zfs-dkms zfsutils-linux"
+fi
+chroot_execute 'cat << DKMS > /etc/dkms/zfs.conf
+# override for /usr/src/zfs-*/dkms.conf:
+# always rebuild initrd when zfs module has been changed
+# (either by a ZFS update or a new kernel version)
+REMAKE_INITRD="yes"
+DKMS'
+
+echo "======= installing OpenSSH and network tooling =========="
+chroot_execute "apt install --yes openssh-server net-tools"
+
+echo "======= setup OpenSSH  =========="
+mkdir -p "$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" "$v_root_password") | chpasswd"
+
+echo "======= setting up zfs cache =========="
+cp /etc/zpool.cache /mnt/etc/zfs/zpool.cache
+
+echo "========setting up zfs module parameters========"
+chroot_execute "echo options zfs zfs_arc_max=$((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_1.2.0-6_amd64.deb
+  wget http://ftp.de.debian.org/debian/pool/main/d/dropbear/dropbear-bin_2020.81-3_amd64.deb
+  wget http://ftp.de.debian.org/debian/pool/main/d/dropbear/dropbear-initramfs_2020.81-3_all.deb
+
+  chroot_execute "dpkg -i /root/libtommath1_1.2.0-6_amd64.deb"
+  chroot_execute "dpkg -i /root/dropbear-bin_2020.81-3_amd64.deb"
+  chroot_execute "dpkg -i /root/dropbear-initramfs_2020.81-3_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