From Debian 10 to Debian 11

Debian 11 (bullseye) has been available for use on the stable channel for several months now. This release contains a total of 59,551 packages of which more than 11,294 are new, and this despite a significant reduction of more than 9,519 packages that were marked as obsolete and were removed. 42,821 packages have been updated and 5,434 remain unchanged. That is, a large number of improvements and bug fixes that will improve our server.

Today we are going to see how to upgrade our system from Debian 10 to Debian 11 in a few steps.

Current system backup

The first and foremost thing is to have a backup of the system. The update should not break anything, but just in case. We are going to make a backup with Duplicati.

Updating current packages

Update existing Debian 10 packages to the latest version using the following commands:

$ sudo apt-get update -y
$ sudo apt-get upgrade -y
$ sudo apt-get dist-upgrade -y
$ sudo apt-get autoremove -y
$ sudo apt-get clean -y
$ sudo reboot

Modifying the repositories

Modify the list of system repositories with the command sudo nano /etc/apt/sources.list replacing those that contain the word buster with the following:

deb http://deb.debian.org/debian/ bullseye main contrib non-free
deb-src http://deb.debian.org/debian/ bullseye main contrib non-free

deb http://security.debian.org/debian-security bullseye-security main contrib non-free
deb-src http://security.debian.org/debian-security bullseye-security main contrib non-free

deb http://deb.debian.org/debian/ bullseye-updates main
deb-src http://deb.debian.org/debian/ bullseye-updates main

(Optional) Update Docker key

If we have Docker installed, it is recommended to update the GPG key with the following commands:

$ sudo curl -fsSL https://download.docker.com/linux/debian/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg
$ sudo echo "deb [arch=amd64 signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/debian $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

If it asks to overwrite, confirm.

Upgrading to Debian 11

At last, run the following commands to upgrade your system to Debian 11.

$ sudo apt-get update -y
$ sudo apt-get full-upgrade -y
$ sudo reboot

During installation, keep the local settings in case you ask us to make changes (this is usually the default option).

Updating and cleaning packages

Finally, update all installed packages and perform a cleanup of obsolete packages with the following commands:

$ apt-get update -y
$ apt-get upgrade -y
$ apt-get dist-upgrade -y
$ apt-get autoremove -y
$ apt-get clean -y
$ sudo reboot

Repeat this list of commands again until the result of each one indicates that no more packages have to be installed, updated and/or deleted.

Conclusion

You can check the version of Debian installed on the system with the command lsb_release -a.

Distributor ID: Debian
Description:    Debian GNU/Linux 11 (bullseye)
Release:        11
Codename:       bullseye

Following the list of commands in this tutorial, our server will be updated to Debian 11 and we will have stable support for 5 years. Remember to keep the packages updated to avoid different failures and to have a healthy system.

References

• Thanks to José Antonio Simancas (JASimancas)
• Cybercity - How to upgrade Debian 10 to Debian 11 Bullseye using the CLI
• Docker Docs - Install Docker Engine on Debian