I love ZFS but it definitely doesn’t fit every situation. One situation it doesn’t fit is Surface Go. Not only device is low on RAM but it’s also low on disk space. And ZFS really hates when it doesn’t have enough disk space.
Now, one can install Ubuntu perfectly well without any shenanigans. Just follow a guide on how to boot install USB and you’re golden. But I like my installations to be a bit special. :)
After booting into Ubuntu desktop installation one needs a root prompt. All further commands are going to need root credentials anyhow.
sudo -i
The very first step should be setting up a few variables - disk, pool, host name, and user name. This way we can use them going forward and avoid accidental mistakes. Just make sure to replace these values with ones appropriate for your system.
DISK=/dev/disk/by-id/^^ata_disk^^
HOST=^^desktop^^
USER=^^user^^
Disk setup is really minimal .
blkdiscard $DISK
sgdisk --zap-all $DISK
sgdisk -n1:1M:+63M -t1:EF00 -c1:EFI $DISK
sgdisk -n2:0:+448M -t2:8300 -c2:Boot $DISK
sgdisk -n3:0:0 -t3:8309 -c3:Ubuntu $DISK
sgdisk --print $DISK
I usually encrypt just the root partition as having boot partition unencrypted does offer advantages and having standard kernels exposed is not much of a security issue.
cryptsetup luksFormat -q --cipher aes-xts-plain64 --key-size 512 \
--pbkdf pbkdf2 --hash sha256 $DISK-part3
Since crypt device name is displayed on every startup, for Surface Go I like to use host name here.
cryptsetup luksOpen $DISK-part3 $HOST
Now we can prepare all needed partitions.
yes | mkfs.ext4 /dev/mapper/$HOST
mkdir /mnt/install
mount /dev/mapper/$HOST /mnt/install/
yes | mkfs.ext4 $DISK-part2
mkdir /mnt/install/boot
mount $DISK-part2 /mnt/install/boot/
mkfs.msdos -F 32 -n EFI $DISK-part1
mkdir /mnt/install/boot/efi
mount $DISK-part1 /mnt/install/boot/efi
To start the fun we need debootstrap package.
apt install --yes debootstrap
And then we can get basic OS on the disk. This will take a while.
debootstrap focal /mnt/install/
Our newly copied system is lacking a few files and we should make sure they exist before proceeding.
echo $HOST > /mnt/install/etc/hostname
sed "s/ubuntu/$HOST/" /etc/hosts > /mnt/install/etc/hosts
sed '/cdrom/d' /etc/apt/sources.list > /mnt/install/etc/apt/sources.list
cp /etc/netplan/*.yaml /mnt/install/etc/netplan/
If you are installing via WiFi, you might as well copy your wireless credentials:
mkdir -p /mnt/install/etc/NetworkManager/system-connections/
cp /etc/NetworkManager/system-connections/* /mnt/install/etc/NetworkManager/system-connections/
Finally we’re ready to “chroot” into our new system.
mount --rbind /dev /mnt/install/dev
mount --rbind /proc /mnt/install/proc
mount --rbind /sys /mnt/install/sys
chroot /mnt/install \
/usr/bin/env DISK=$DISK HOST=$HOST USER=$USER \
bash --login
Let’s not forget to setup locale and time zone.
locale-gen --purge "en_US.UTF-8"
update-locale LANG=en_US.UTF-8 LANGUAGE=en_US
dpkg-reconfigure --frontend noninteractive locales
dpkg-reconfigure tzdata
Now we’re ready to onboard the latest Linux image.
apt update
apt install --yes --no-install-recommends linux-image-generic linux-headers-generic
Followed by boot environment packages.
apt install --yes initramfs-tools cryptsetup keyutils grub-efi-amd64-signed shim-signed tasksel
Since we’re dealing with encrypted data, we should auto mount it via crypttab. If there are multiple encrypted drives or partitions, keyscript really comes in handy to open them all with the same password. As it doesn’t have negative consequences, I just add it even for a single disk setup.
echo "$HOST UUID=$(blkid -s UUID -o value $DISK-part3) none \
luks,discard,initramfs,keyscript=decrypt_keyctl" >> /etc/crypttab
cat /etc/crypttab
To mount boot and EFI partition, we need to do some fstab setup too:
echo "UUID=$(blkid -s UUID -o value /dev/mapper/$HOST) \
/ ext4 noatime,nofail,x-systemd.device-timeout=5s 0 1" >> /etc/fstab
echo "PARTUUID=$(blkid -s PARTUUID -o value $DISK-part2) \
/boot ext4 noatime,nofail,x-systemd.device-timeout=5s 0 1" >> /etc/fstab
echo "PARTUUID=$(blkid -s PARTUUID -o value $DISK-part1) \
/boot/efi vfat noatime,nofail,x-systemd.device-timeout=5s 0 1" >> /etc/fstab
cat /etc/fstab
Now we get grub started and update our boot environment.
KERNEL=`ls /usr/lib/modules/ | cut -d/ -f1 | sed 's/linux-image-//'`
update-initramfs -u -k $KERNEL
Grub update is what makes EFI tick.
update-grub
grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=Ubuntu \
--recheck --no-floppy
Finally we install out GUI environment. I personally like ubuntu-desktop-minimal but you can opt for ubuntu-desktop. In any case, it’ll take a considerable amount of time.
tasksel install ubuntu-desktop-minimal
Short package upgrade will not hurt.
apt dist-upgrade --yes
The only remaining task before restart is to create the user, assign a few extra groups to it, and make sure its home has correct owner.
sudo adduser --disabled-password --gecos '' $USER
usermod -a -G adm,cdrom,dip,lpadmin,plugdev,sudo $USER
passwd $USER
As install is ready, we can exit our chroot environment.
exit
And unmount our disk:
umount /mnt/install/boot/efi
umount /mnt/install/boot
mount | tac | awk '/\/mnt/ {print $3}' | xargs -i{} umount -lf {}
After the reboot you should be able to enjoy your installation.
reboot
PS: If you are doing install on normal desktop, check similar ZFS-based installation guide.
