Let’s try to upgrade to Ubuntu Server 20.04 after a backup

Motivation

I want to play around and learn ROS2, however the WSL environment on windows doesn’t seem fit. Also I am not keen on installing the Windows Version of ROS2 yet, as my work environment for ROS will stay Linux / Ubuntu anyway. So let’s upgrade my Homeserver to 20.04 instead to install ROS2 there.

Whatever, take me to the TR:DL already

Backing up the original rootfs

Since I installed the original filesystem in a seperate sub volume, this task is really easy. Just make a snapshot and for good measure, also send it to a second external btrfs drive.

❯ cd /mnt/btrfs
❯ ls
@rootfs
❯ mount /dev/sdd /mnt/temp
❯ btrfs sub snap -r @rootfs @rootfs_ro_18_04
Create a readonly snapshot of '@rootfs' in './@rootfs_ro_18_04'
❯ btrfs send @rootfs_ro_18_04 | btrfs rec /mnt/temp
At subvol @rootfs_ro_18_04
At subvol @rootfs_ro_18_04

Important to note is, this didn’t backup the btrfs subvolumes created by lxd, but They are not overly important to me on this device right now. I have backups of those containers in other places already. I am just hoping the upgrade will finish smoothly anyway.

Upgrade the OS

Getting right to it.

# make sure the system is up to date
apt update && apt dist-upgrade -y
# make sure upgrade manage is installed
apt install update-manager-core
# confirm that lts release upgrade is selected
cat /etc/update-manager/release-upgrades

During the upgrade, the ssh session might disconnect. The upgrade manage will open a second ssh session on port 1022. So, just in case make sure the firewall allows that port, too.

Start the upgrade process

do-release-upgrade

If this appears

❯ do-release-upgrade
Checking for a new Ubuntu release
There is no development version of an LTS available.
To upgrade to the latest non-LTS develoment release
set Prompt=normal in /etc/update-manager/release-upgrades.

the upgrade needs to be forced to check for “development” versions, too. Even after release it seems it’s marked as that.

do-release-upgrade -d

Now just follow the on screen instructions, should be straight forward.

Problems

• I had a binded mount pointing from my storage hdd into the rootfs of an lxc container. This mount didn’t work anymore, because the rootfs location changed from /var/lib/lxd to /var/snap/lxd/common.
• Inside an lxc container, nordvpn was not working anymore. Removed it and reset the ip tables rules. I tried reinstalling, but than it couldn’t connect to their servers. I will try using it on a new 20.04 container some other time.

TL;DR

Maybe there won’t be a TLDR for this post.