Microsoft shifts Azure Linux to general-purpose availability at Build 2026

Microsoft has released Azure Linux 4.0 into public preview at Build 2026, marking the first time the distribution is available as a general-purpose operating system for any Azure virtual machine. Previously restricted to special-purpose infrastructure roles, the new release allows users to explicitly select the operating system, moving beyond its history as an underlying host for services such as Azure Kubernetes Service.

The architecture of Azure Linux 4.0 represents a significant shift from previous versions. Derived from a Fedora 43 snapshot, the distribution no longer relies on assembling packages package-by-package or maintaining every specification file manually. Instead, it tracks Fedora upstream and applies declarative overlays, where every deviation from the Fedora baseline is documented with a written explanation. This approach ensures that rendered specification files are checked into the repository, providing full visibility into Microsoft’s modifications.

Security and supply chain transparency have been central to the development of this release. The operating system features enhanced security protocols, including SELinux support on every image, kernel hardening with ASLR and stack protection, and cryptographically signed packages. Microsoft also publishes Software Bill of Materials for supply chain transparency, aligning with broader industry efforts to secure the software supply chain through initiatives such as OpenSSF and Alpha-Omega.

The distribution has already seen substantial adoption within Microsoft’s own ecosystem. Databricks has migrated more than 100,000 virtual machines and over a million CPU cores to Azure Linux, while LinkedIn has also moved its infrastructure to the platform. It currently runs behind major services including Azure SQL and Cosmos DB, building on a lineage that began with internal development in September 2019 and the public release of its GitHub repository in November 2020.

This release follows a long trajectory for Microsoft’s engagement with Linux, which began with hosting Linux virtual machines in 2012 and joining the Linux Foundation in 2016. Today, more than two-thirds of customer cores on Azure run Linux. The availability of Azure Linux 4.0 from the Azure marketplace in two clicks signals a logical progression from consuming Linux to shipping a maintained, upstream-first distribution that anyone can run.