add ability to install debian 12 in UEFI mode (#76)

check, whether the machine is booted in EFI mode, then setup an EFI
partition and install efi grub instead of legacy grub.
This is required, since new hetzner machines don't have the ability
to boot in legacy mode anymore.

Co-authored-by: Micha Goetz <mg@altasigma.com>
Co-authored-by: Nemo <9478806+terem42@users.noreply.github.com>

hetzner-debian12-zfs-setup.sh

@@ -49,6 +49,7 @@ 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=$c_log_dir/disks.log
+c_efimode_enabled="$(if [[ -d /sys/firmware/efi/efivars ]]; then echo 1; else echo 0; fi)"
 
 function activate_debug {
   mkdir -p "$c_log_dir"
@@ -522,7 +523,11 @@ echo "======= partitioning the disk =========="
 
   for selected_disk in "${v_selected_disks[@]}"; do
     wipefs --all --force "$selected_disk"
-    sgdisk -a1 -n1:24K:+1000K            -t1:EF02 "$selected_disk"
+    if (( c_efimode_enabled == 1 )); then
+      sgdisk -a1 -n1:24K:+1G            -t1:EF00 "$selected_disk" # EFI partition
+    else
+      sgdisk -a1 -n1:24K:+1000K            -t1:EF02 "$selected_disk"
+    fi
     sgdisk -n2:0:+2G                   -t2:BF01 "$selected_disk" # Boot pool
     sgdisk -n3:0:"$tail_space_parameter" -t3:BF01 "$selected_disk" # Root pool
   done
@@ -553,8 +558,22 @@ echo "======= create zfs pools and datasets =========="
 
 # shellcheck disable=SC2086
 zpool create \
-  $v_bpool_tweaks -O canmount=off -O devices=off \
   -o cachefile=/etc/zpool.cache \
+  -o ashift=12 -d \
+  -o feature@async_destroy=enabled \
+  -o feature@bookmarks=enabled \
+  -o feature@embedded_data=enabled \
+  -o feature@empty_bpobj=enabled \
+  -o feature@enabled_txg=enabled \
+  -o feature@extensible_dataset=enabled \
+  -o feature@filesystem_limits=enabled \
+  -o feature@hole_birth=enabled \
+  -o feature@large_blocks=enabled \
+  -o feature@lz4_compress=enabled \
+  -o feature@spacemap_histogram=enabled \
+  -o feature@zpool_checkpoint=enabled \
+  -O acltype=posixacl -O canmount=off -O compression=lz4 \
+  -O devices=off -O normalization=formD -O relatime=on -O xattr=sa \
   -O mountpoint=/boot -R $c_zfs_mount_dir -f \
   $v_bpool_name $pools_mirror_option "${bpool_disks_partitions[@]}"
 
@@ -606,6 +625,16 @@ if [[ $v_swap_size -gt 0 ]]; then
   mkswap -f "/dev/zvol/$v_rpool_name/swap"
 fi
 
+if (( c_efimode_enabled == 1 )); then
+echo "======= create filesystem on EFI partition(s) =========="
+
+  for selected_disk in "${v_selected_disks[@]}"; do
+    mkfs.fat -F32 "${selected_disk}-part1"
+  done
+  mkdir -p "$c_zfs_mount_dir/boot/efi"
+  mount "${v_selected_disks[0]}-part1" "$c_zfs_mount_dir/boot/efi"
+fi
+
 echo "======= setting up initial system packages =========="
 debootstrap --arch=amd64 bookworm "$c_zfs_mount_dir" "$c_deb_packages_repo"
 
@@ -694,7 +723,6 @@ 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"
@@ -752,12 +780,22 @@ 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 "apt install --yes grub-legacy"
-chroot_execute "apt install --yes grub-pc"
-for disk in ${v_selected_disks[@]}; do
-  chroot_execute "grub-install --recheck $disk"
-done
+if (( c_efimode_enabled == 1 )); then
+  chroot_execute "apt install --yes grub-efi-amd64"
+else
+  chroot_execute "echo 'grub-pc grub-pc/install_devices_empty   boolean true' | debconf-set-selections"
+  chroot_execute "apt install --yes grub-legacy"
+  chroot_execute "apt install --yes grub-pc"
+fi
+
+if (( c_efimode_enabled == 1 )); then
+  #chroot_execute grub-probe /boot
+  chroot_execute grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=debian --recheck
+else
+  for disk in ${v_selected_disks[@]}; do
+    chroot_execute "grub-install --recheck $disk"
+  done
+fi
 
 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"
@@ -855,6 +893,10 @@ else
 fi
 
 echo "======= setting mountpoints =========="
+if (( c_efimode_enabled == 1 )); then
+  umount "$c_zfs_mount_dir/boot/efi"
+fi
+
 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"