CERN is preparing one of the most interesting Debian 13 deployments of 2026. More than 2,200 industrial computers and embedded systems used across its accelerator control infrastructure are expected to run Debian 13 “Trixie” by the end of the year, affecting machines connected to around 17,000 devices across facilities spanning roughly 43 square kilometres.
The key points about CERN’s move to Debian 13 in 20 seconds
- More than 2,200 industrial and embedded systems are expected to migrate to Debian 13 by the end of 2026.
- The control infrastructure communicates with approximately 17,000 devices.
- CERN has a long history with the Red Hat ecosystem through Scientific Linux and CentOS.
- Staying on that path could have required hardware redesigns estimated at around CHF 5.4 million.
- Debian offered a way to address much of the problem in software rather than replacing working hardware.
These are not CERN’s office PCs, nor is this a conventional server migration. The affected computers form part of the computing layer located close to accelerator equipment, where software interfaces with specialised electronics and devices used throughout the accelerator complex.
The decision was detailed by CERN engineers Federico Vaga and Nikos Tsipinakis during MiniDebConf Winterthur 2026. The Debian Project has also confirmed the plan to have the 2,200-plus industrial computers and embedded systems running Debian 13 before the end of the year.
The migration is particularly notable because of CERN’s long relationship with Linux distributions from the Red Hat family.
From Scientific Linux and CentOS to Debian
Linux has been part of CERN’s computing infrastructure for decades.
Its accelerator control systems previously went through several generations of Scientific Linux, the Red Hat Enterprise Linux (RHEL)-based distribution originally developed by Fermilab and CERN.
CentOS followed, including systems associated with the RHEL 7 and RHEL 8 generations.
The change in direction of CentOS, with the traditional CentOS Linux model being replaced by CentOS Stream, forced CERN’s accelerator controls team to reconsider how dependent it wanted to remain on that ecosystem.
The original response was not to abandon it immediately.
CERN considered validating CentOS Stream 9, moving to Stream 10 as soon as practical and potentially adopting later versions in the future.
At the same time, however, engineers began working on something that would prove important: reducing the control infrastructure’s dependence on any single Linux distribution.
The idea was to make CERN’s integration layer sufficiently distribution-agnostic that another operating system could serve as a fallback.
That alternative was Debian.
What began as a contingency plan became considerably more attractive once engineers analysed what remaining on the previous path could mean for CERN’s specialised hardware.
A software problem that could have forced hardware replacements
One of the most revealing parts of the project comes from a risk analysis carried out in the second quarter of 2023.
According to figures presented by CERN engineers, remaining on the Red Hat Enterprise Linux path could have resulted in costs of approximately CHF 5.4 million.
The issue went far beyond software licensing or the engineering time required to install another operating system.
Compatibility with specialised accelerator hardware could have required the redesign of around 11 hardware boards, additional electronics and software engineers and technicians, as well as rack reorganisation and rewiring.
A large number of systems could also have been affected during commissioning.
Even assuming bug-free replacement hardware, CERN’s analysis put the optimistic probability of success at only around 20%.
There was another resource that could not simply be purchased: time.
The infrastructure needed to be ready by the fourth quarter of 2026.
CERN therefore chose a conceptually simpler route: addressing a software-originated problem through software, rather than redesigning substantial amounts of working hardware merely to remain compatible with a particular operating-system family.
Debian consequently moved from being the backup option to the operating system selected for this part of CERN’s infrastructure.
Updating Linux when Linux helps control an accelerator
The migration also illustrates why choosing a Linux distribution for industrial infrastructure can have consequences lasting many years.
An ordinary server can usually be rebooted during a maintenance window. In virtualised environments, workloads can sometimes be moved elsewhere while the underlying system is serviced.
Computers involved in controlling CERN’s accelerators operate under very different constraints.
Accelerator operations follow carefully planned schedules containing physics runs, technical stops, commissioning periods and long shutdowns. Operating-system upgrades therefore need to fit around the accelerator rather than the other way around.
CERN’s engineers highlighted the problem with a memorable example: the organisation wants to avoid finding itself having to “hotpatch a live particle accelerator.”
The choice of Debian 13 is consequently connected not only to compatibility but also to lifecycle planning and the need for a stable software platform throughout the expected operational period.
The timing is particularly relevant because CERN has entered Long Shutdown 3 (LS3).
The Large Hadron Collider completed its Run 3 physics programme in June 2026, while CERN’s injector complex moved towards the shutdown at the end of August. The extended maintenance period will include major work required for the future High-Luminosity LHC (HL-LHC).
CERN’s current schedule places the start of HL-LHC operation in June 2030.
Debian has to work with highly specialised hardware
Installing Debian 13 does not automatically solve every engineering challenge.
CERN has developed specialised electronics for its accelerator infrastructure over many years. Many of the 2,200 affected computers are not conventional servers sitting inside a data centre. They are industrial and embedded systems located close to equipment and communicating directly with accelerator electronics.
The migration therefore also involves work on device drivers, the way front-end computers boot and the infrastructure used to distribute operating-system components.
One of the broader objectives is to remove assumptions that tie specialised hardware too closely to one Linux distribution.
That work could ultimately prove more important than the choice between Debian, CentOS Stream or another distribution.
An infrastructure with fewer distribution-specific dependencies gives engineers more freedom when selecting future operating systems. It also reduces the possibility that an external change in a Linux distribution forces an organisation to replace hardware that remains technically capable of doing its job.
The deployment also demonstrates how deeply Linux is embedded inside CERN.
The laboratory’s accelerator complex currently includes nine accelerators and two decelerators, together with an extensive chain of machines that prepare and transport particles before they reach facilities such as the Large Hadron Collider. Accelerator operations are managed around the clock from the CERN Control Centre.
Behind the spectacular images of detectors and particle collisions sits a substantial computing infrastructure that receives far less public attention.
Debian 13 is now set to occupy a particularly interesting position within it.
This will not simply be another large Linux installation involving thousands of machines. Debian will be running on computers interacting with thousands of devices across one of the world’s most sophisticated scientific infrastructures.
There is also a useful engineering lesson behind CERN’s decision: making software less dependent on a specific distribution can prevent perfectly functional hardware from having to be redesigned or replaced when the software ecosystem changes.
Frequently Asked Questions
How many CERN systems will run Debian 13?
The target is for more than 2,200 industrial computers and embedded systems associated with CERN’s accelerator controls to be running Debian 13 by the end of 2026.
Is CERN completely abandoning Red Hat for Debian?
No. The migration described here specifically concerns the computing infrastructure used for accelerator controls. It does not mean that every CERN server, workstation or computing environment is moving to Debian.
Why did CERN choose Debian 13?
The reasons presented by CERN engineers include hardware compatibility, lifecycle planning and reducing dependence on a specific Linux distribution. Continuing along the previous path could have required extensive hardware modifications and additional engineering resources.
Will Debian 13 directly control the LHC?
The migration concerns CERN’s broader accelerator control infrastructure, consisting of thousands of industrial computers and embedded systems connected to around 17,000 devices. CERN operates many accelerators in addition to the LHC, so describing all 2,200 systems simply as “computers controlling the LHC” would be inaccurate.