According to the blog post on melashri.net, the author argues that abandoning Scientific Linux was a mistake. The post notes that by the end of 2026, more than 2,200 industrial computers and embedded systems around CERN’s accelerator complex are expected to be running Debian 13. While AlmaLinux and RHEL remain the main supported Linux distributions across much of the organization, Debian support is currently limited to accelerator front‑end systems. The author traces the history of Scientific Linux, which Fermilab announced in 2003 and CERN joined soon afterward. Scientific Linux grew out of a practical problem in high‑energy physics: the need for a stable, freely redistributable, enterprise‑grade Linux that could work across institutions without requiring a commercial license for every machine. By turning Red Hat Enterprise Linux source into a community resource, Scientific Linux gave the scientific community an institutionally independent implementation of the Enterprise Linux platform. When Red Hat and CentOS joined forces in 2014, moving to CentOS looked reasonable because CentOS already offered a freely available Enterprise Linux rebuild backed by a larger community. CERN began migrating its next major release from Scientific Linux CERN to CERN CentOS 7, and Scientific Linux 5 and 6 remained supported. In 2019, Fermilab took the argument to its logical conclusion, deciding there would be no Scientific Linux 8 and deploying CentOS 8 instead, working with CERN and other laboratories to improve CentOS for high‑energy physics. The author says this decision removed something hard to see on a spreadsheet: a credible exit. Maintaining Scientific Linux involved visible costs—rebuilding packages, testing updates, maintaining repositories, producing releases, handling security updates, and supporting users. Its benefit was harder to quantify: as long as CentOS behaved as expected, Scientific Linux looked redundant. However, Scientific Linux kept alive the people, processes, infrastructure, and institutional knowledge needed to maintain an independent RHEL‑compatible distribution, giving the community option value. That option became valuable when assumptions changed. In December 2020, Red Hat changed the role of CentOS, discontinuing the traditional downstream rebuild in favor of CentOS Stream, which sits ahead of RHEL. Organizations that had standardized on CentOS for a freely distributable approximation of the current RHEL release found the product they relied on effectively ceased to exist. CERN and Fermilab had to reconsider their Linux strategy, noting that the shorter CentOS Stream lifecycle was incompatible with some scientific use cases. By 2022, they were recommending AlmaLinux as the standard distribution for experiments. In 2023, Red Hat changed how RHEL‑related sources were publicly distributed, making CentOS Stream the sole public repository for that source material. The author writes that this did not make RHEL ‘closed source’ but made the dependency structure of the Enterprise Linux rebuild ecosystem much clearer. The post concludes that Scientific Linux had strategic value that was never properly accounted for: its existence meant CERN, Fermilab, and other institutions were not merely consumers of an ecosystem but could reproduce a critical part of it themselves. Once discarded, that capability is much harder to recreate than to keep alive. The latest chapter, the author adds, makes this history particularly interesting: CERN’s accelerator controls group first tried to remain within the Red Hat ecosystem, preparing Debian as a fallback because they could not afford new surprises, before moving part of the accelerator complex to Debian.
