I run Debian 10 Buster on all of my Proxmox VMs. This
week, Debian 11 Bullseye was released, so it’s time to upgrade. You can check with
cat /etc/os-release what OS version
you’re running at the moment. For further details on the upgrade process, check out the
official Debian upgrade guide.
I strongly recommend executing all of these steps in a
tmux session. The SSH
connection might get interrupted during the upgrade and with
tmux you can easily reconnect to the terminal.
Furthermore, I also strongly recommend making a backup of your system before attempting the upgrade.
First, upgrade all packages to the lastest version available in Buster:
sudo apt update sudo apt full-upgrade
Now the repository has to be changed from Buster to Bullseye. In the repository configuration file
bullseye. The security suite is now named
bullseye-security instead of
has to be renamed as well. I also noticed that all the sources were defined with HTTP connections, so let’s convert
those to HTTPS while we’re at it. It’s a good idea to either keep a backup of the old
/etc/apt/sources.list file or
comment out the existing lines instead of modifying them. That way you can revert in case anything goes wrong.
deb http://deb.debian.org/debian/ buster main deb http://deb.debian.org/debian/ buster-updates main deb http://security.debian.org/debian-security buster/updates main
deb https://deb.debian.org/debian/ bullseye main deb https://deb.debian.org/debian/ bullseye-updates main deb https://deb.debian.org/debian-security bullseye-security main contrib
ls -l /etc/apt/sources.list.d/ whether there are any custom source configuration files that need to change
bullseye. If so, change them as well.
Now it’s time to perform the upgrade and remove unused dependencies:
sudo apt clean sudo apt update sudo apt full-upgrade sudo apt autoremove
Finally, reboot the machine with
sudo shutdown -r now. You’ll be running Debian 11 Bullseye.