Sythos

Posted on Sep 7 AI-assisted

CERN Is Moving 2,200 Accelerator Systems to Debian 13 — No USB Stick Required

#linux #debian #opensource #devops

This is one of those Linux stories that deserves attention even beyond the usual distro wars.

By the end of 2026, CERN plans to move more than 2,200 industrial computers and embedded systems to Debian 13 “Trixie”. These machines are connected to roughly 17,000 devices spread across an area of about 43 square kilometres.

So no, this is not a researcher replacing the operating system on a laptop between two coffee breaks. Linux is moving directly into one of the most complex scientific infrastructures on the planet.

The backstory matters

For many years, CERN lived in the Red Hat ecosystem: first with Scientific Linux, developed in part by CERN and Fermilab, and later with CentOS.

Then CentOS Linux changed direction. Red Hat discontinued the traditional model and moved the project towards CentOS Stream.

That was a perfectly legitimate business decision, of course. But when an organisation chooses CentOS specifically for its stability, predictability and long life cycles, a few eyebrows may go up.

Probably in Geneva too.

The CERN problem was very practical. Continuing down the expected migration path could have required changing not only software, but also a significant amount of specialised hardware.

A 2023 risk assessment considered a scenario involving:

roughly CHF 5.4 million in costs;
redesigning 11 electronic boards;
rack modifications;
extensive rewiring;
many hours of work from technicians and engineers;
and an estimated success probability of around 20%.

At some point, someone probably remembered an old and rather useful feature of software:

You can change it.

Hardware invoices are usually less flexible.

Change the software, not the accelerator

Instead of modifying a mountain of perfectly functional hardware to fit a new operating system, CERN chose the opposite direction.

The goal was to make its software less dependent on one specific Linux distribution and select a platform that fitted the existing infrastructure more naturally.

The choice fell on Debian 13 “Trixie”.

Naturally, this does not mean inserting a USB stick into 2,200 machines, clicking “Install Debian”, and going out for coffee.

The migration includes:

software distribution systems;
boot procedures;
drivers for specialised hardware;
and, most importantly, the gradual removal of distribution-specific dependencies.

There is another small detail: these systems control particle accelerators.

That means updates and migrations have to be coordinated with maintenance windows and the operational calendar of the accelerators.

The classic Friday afternoon deploy followed by “What could possibly go wrong?” is probably considered a crime against humanity here.

Debian at CERN does not mean “Red Hat is gone”

There is an important clarification behind some of the headlines: CERN is not abandoning Red Hat or its wider ecosystem completely.

The move to Debian focuses on industrial and embedded systems used for accelerator control.

Other parts of the infrastructure, including datacentres and systems used by the experiments, will continue to use platforms such as RHEL and AlmaLinux.

Still, the decision is significant.

Debian is a community distribution that has spent three decades prioritising stability, compatibility and predictability instead of reinventing itself commercially every few years.

Now it is going to run thousands of systems belonging to one of the most advanced scientific infrastructures in the world.

There is also a nice bit of irony here. After all the changes around CentOS, one of the world’s most important scientific organisations ended up choosing a distribution famous for a very simple philosophy:

It will be released when it is ready.

When you are controlling a particle accelerator, that may not be a bad philosophy at all.

Sources and further reading

Image note

The banner image was generated with AI for illustrative purposes. I’m hopeless at the artistic stuff, so I let the machine handle the drawing. It is not an official CERN photograph or communication.

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