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title: 'Ubuntu server 20.04 zfs root and OCI'
date: '2020-02-21T13:02:12-06:00'
status: publish
permalink: /ubuntu-server-20-04-zfs-root-and-oci
author: admin
excerpt: ''
type: post
id: 1449
    - Ubuntu
    - ZFS
tag: []
post_format: []

My experiment to:

  • create an Ubuntu 20.04 (not final release as of Feb 20) server in Virtualbox
  • setup server with a ZFS root disk
  • enable serial console
  • Virtualbox export to OCI

As you probably know newer desktop versions of Ubuntu will offer ZFS for root volume during installation. I am not sure if that is true in Ubuntu 20.04 server installs and when I looked at the 19.10 ZFS installation I did not necessarily want to use the ZFS layout they did. My experiment is my custom case and also tested on Ubuntu 16.04 and 18.04.

Note this is an experiment and ZFS layout, boot partition type, LUKS, EFI, multiple boot disks(mirrored) and netplan are all debatable configurations. Mine may not be ideal but it works for my use case.

Also my goal here was to export a bootable/usable OCI (Oracle Cloud Infrastructure) compute instance.

Start by booting a recent desktop live CD. Since I am testing 20.04 (focal) I used that. In the live cd environment open a terminal, sudo and apt install ssh. Start the ssh service and set ubuntu user password.

```bash $ ssh ubuntu@ $ sudo -i

apt-add-repository universe apt update apt install --yes debootstrap gdisk zfs-initramfs

find correct device name for below

DISK=/dev/disk/by-id/ata-VBOX_HARDDISK_VB26c080f2-2bd16227 USER=ubuntu HOST=server POOL=ubuntu

sgdisk --zap-all $DISK sgdisk --zap-all $DISK sgdisk -a1 -n1:24K:+1000K -t1:EF02 $DISK sgdisk -n2:1M:+512M -t2:EF00 $DISK sgdisk -n3:0:+1G -t3:BF01 $DISK sgdisk -n4:0:0 -t4:BF01 $DISK sgdisk --print $DISK

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

zpool create -o ashift=12 \ -O acltype=posixacl -O canmount=off -O compression=lz4 \ -O dnodesize=auto -O normalization=formD -O relatime=on -O xattr=sa \ -O mountpoint=/ -R /mnt rpool ${DISK}-part4

zfs create -o canmount=off -o mountpoint=none rpool/ROOT zfs create -o canmount=off -o mountpoint=none bpool/BOOT

zfs create -o canmount=noauto -o mountpoint=/ rpool/ROOT/ubuntu zfs mount rpool/ROOT/ubuntu

zfs create -o canmount=noauto -o mountpoint=/boot bpool/BOOT/ubuntu zfs mount bpool/BOOT/ubuntu

Note: I skipped creating datasets for home, root, var/lib/ /var/log etc etc

debootstrap focal /mnt zfs set devices=off rpool

cat > /mnt/etc/netplan/01-netcfg.yaml<< EOF network: version: 2 ethernets: enp0s3: dhcp4: true EOF

cat > /mnt/etc/apt/sources.list<< EOF deb focal main universe EOF

mount --rbind /dev /mnt/dev mount --rbind /proc /mnt/proc mount --rbind /sys /mnt/sys chroot /mnt /usr/bin/env DISK=$DISK bash --login

locale-gen --purge en_US.UTF-8 update-locale LANG=en_US.UTF-8 LANGUAGE=en_US dpkg-reconfigure --frontend noninteractive locales echo US/Central > /etc/timezone
dpkg-reconfigure -f noninteractive tzdata


apt install --yes --no-install-recommends linux-image-generic apt install --yes zfs-initramfs apt install --yes grub-pc grub-probe /boot

update-initramfs -u -k all <- this does not work. try below

KERNEL=ls /usr/lib/modules/ | cut -d/ -f1 | sed 's/linux-image-//' update-initramfs -u -k $KERNEL

edit /etc/default/grub



GRUB_TIMEOUT=5 GRUB_CMDLINE_LINUX_DEFAULT= GRUB_CMDLINE_LINUX=root=ZFS=rpool/ROOT/ubuntu console=tty1 console=ttyS0,115200 GRUB_TERMINAL=serial console GRUB_SERIAL_COMMAND=serial --unit=0 --speed=115200

update-grub grub-install $DISK

cat > /etc/systemd/system/zfs-import-bpool.service<< EOF [Unit] DefaultDependencies=no Before=zfs-import-scan.service Before=zfs-import-cache.service

[Service] Type=oneshot RemainAfterExit=yes ExecStart=/sbin/zpool import -N -o cachefile=none bpool

[Install] EOF

systemctl enable zfs-import-bpool.service

zfs set mountpoint=legacy bpool/BOOT/ubuntu echo bpool/BOOT/ubuntu /boot zfs \ nodev,relatime,x-systemd.requires=zfs-import-bpool.service 0 0 >> /etc/fstab zfs snapshot bpool/BOOT/ubuntu@install zfs snapshot rpool/ROOT/ubuntu@install

systemctl enable serial-getty@ttyS0 apt install ssh systemctl enable ssh


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

** reboot

** detach live cd

NOTE: grub had a prompt on reboot but no options. try below

```bash KERNEL=ls /usr/lib/modules/ | cut -d/ -f1 | sed 's/linux-image-//' update-initramfs -u -k $KERNEL update-grub ````