Azure Linux 4.0 is Microsoft's first general-purpose Linux
Microsoft ships Azure Linux 4.0 as a general-purpose cloud OS based on Fedora, deployable on any Azure VM and coming to WSL.
Azure Linux 4.0 entered public preview at Build 2026, marking the first time Microsoft's in-house Linux runs on any Azure virtual machine rather than just as infrastructure for AKS nodes. The distribution evolved from CBL-Mariner (renamed Azure Linux in March 2024) and now derives from Fedora 43 with declarative overlays documenting each deviation. Technical upgrades include Kernel 6.18 LTS, dnf5 package manager replacing Microsoft's tdnf, glibc 2.42, systemd 258, OpenSSL 3.5 with post-quantum cryptography, Python 3.14, and RPM 6.0. FIPS 140-3 certification is in progress. Azure Linux 4.0 ships across VMs, containers, AKS, and WSL with no additional OS licensing. Databricks migrated 100,000+ VMs and LinkedIn moved infrastructure to Azure Linux. Security features include SELinux support, kernel hardening, and published SBOMs.
What HN community is saying
Most commenters questioned whether calling this "general-purpose" is accurate, noting it lacks desktop environment, GUI, and broad hardware certification outside Azure. One commenter clarified that certification is coming and that distribution maintainers need flexibility over update cadence. The thread split between those viewing this as a straightforward Fedora fork for Azure (making it less noteworthy) and those seeing it as a meaningful cloud-native distro. No substantive concerns about embrace-extend-extinguish emerged; commenters noted GPL licensing and Microsoft's documented changes make lock-in harder than with proprietary layers.