In a significant development for the tech community, Microsoft has unveiled Azure Linux 4.0, a distribution that has transitioned from being an internal tool for Azure to a fully-fledged server operating system. This release allows users to install Azure Linux on their own servers and virtual machines, marking a notable shift in Microsoft’s approach to Linux.
Technical underpinnings: Fedora
At its core, Azure Linux 4.0 is built on Fedora Linux, a choice that reflects Microsoft’s commitment to leveraging established open-source foundations. Lachlan Evenson, a principal program manager on Azure’s open-source team, explained that the decision to use Fedora as the upstream source enables the use of RPMs within the Fedora ecosystem. Microsoft meticulously curates the packages and supply chain to ensure compatibility with Azure’s cloud platform, while also allowing users the flexibility to run it in various environments.
The current beta version of Azure Linux features a hardened Linux kernel 6.18, optimized for performance on Hyper-V and Azure virtual machines. It is designed with security in mind, incorporating SELinux-based security measures and a configuration tailored for cloud and server workloads. Notably, Azure Linux does not include a graphical user interface, catering instead to users who are comfortable navigating through the Bash shell.
Azure Linux positioning
Within the Azure Marketplace, Azure Linux 4.0 is positioned as a “Microsoft-built Linux distribution for Azure,” highlighting its supported lifecycle and integration with Azure’s security features. For users opting to deploy Azure Linux on Azure, formal support and Service Level Agreements (SLAs) are available. However, those choosing to run the distribution on their own hardware will find themselves without official support, as outlined on its GitHub page, which emphasizes community-based assistance for ISO images.
This dual positioning—offering both an ISO for standalone use and a marketplace image for Azure—allows Microsoft to present Azure Linux 4.0 as both a conventional server operating system and a component of its managed infrastructure stack.
Build system and openness
The Azure Linux GitHub repository provides transparency into the distribution’s inner workings, including package specifications, build scripts, and documentation for generating custom images. Microsoft actively encourages community engagement through bug reports and proposals, although it retains control over the base image’s contents, reflecting a vendor-controlled model similar to those employed by other major enterprise Linux providers.
By offering a free, Azure-optimized server operating system that can also be utilized on-premises, Microsoft aims to establish Azure Linux as the go-to Linux solution across hybrid environments. This strategy not only enhances integration between Linux and Azure’s broader infrastructure but also signals a potential future shift away from Windows Server, which has seen declining popularity in favor of Linux within Azure’s ecosystem.
