Microsoft open-sources WSL, ships Azure Linux

Microsoft has put the Windows Subsystem for Linux codebase on GitHub and is pairing that move with a new Azure Linux release aimed at cloud-native and AI workloads. The two announcements came as Microsoft used open-source forums ahead of its Build conference to describe changes to the developer and infrastructure layers under its AI business. Microsoft’s WSL documentation says the project is now open source, while the public repository shows active releases and contribution guidance. The Azure side of the push is arriving in stages. In a Microsoft open-source blog post published May 18, the company said Azure Linux 4.0 is headed to public preview on Azure Virtual Machines and that Azure Container Linux is now generally available. Microsoft said the broader rollout would come at Build on June 2. (learn.microsoft.com) ### What exactly changed with WSL? Windows Subsystem for Linux is now described by Microsoft as an open-source project, with source code available for download and build instructions published in Microsoft Learn. The GitHub repository includes contributor guidance, developer documentation and recent release activity, indicating Microsoft is treating WSL as a public development project rather than only a packaged Windows feature. (opensource.microsoft.com) WSL has long let developers run Linux tools and distributions on Windows without a separate dual-boot setup. Microsoft’s documentation continues to describe it as a way to run GNU/Linux command-line tools, utilities and applications directly on Windows. ### What is Microsoft shipping on Azure? Azure Linux 4.0 is the new operating system release Microsoft is positioning for cloud-native and AI workloads. (learn.microsoft.com) In its May 18 post, Microsoft said the version will enter public preview on Azure Virtual Machines and described it, together with Azure Container Linux, as a hardened Linux offering built for cloud-native and AI use cases. (learn.microsoft.com) Azure Container Linux is already generally available, according to Microsoft. The company described it as an immutable, container-optimized operating system and said the Build conference on June 2 would bring a broader rollout. ### How does this fit with Microsoft’s existing Linux stack? (opensource.microsoft.com) Azure Linux is not a new name in Microsoft’s cloud stack, but the company is extending it. Microsoft Learn says the Azure Linux container host for Azure Kubernetes Service is an open-source Linux distribution created by Microsoft and based on CBL-Mariner, with support across AKS and related products. (opensource.microsoft.com) Microsoft’s support documentation also shows a release cadence for Azure Linux major versions of about every three years, with major image updates covering packages, kernels, security and tooling. That gives Azure Linux 4.0 the shape of a platform release rather than a narrow feature update. ### Why are WSL and Azure Linux being discussed together? (learn.microsoft.com) Microsoft linked the announcements itself in its May 18 open-source summit post, saying the updates were meant to strengthen the environment developers and organizations use for cloud-native and AI workloads. The company’s wording tied developer tooling, container infrastructure and operating-system hardening into one message ahead of Build. (learn.microsoft.com) That framing places the emphasis below the application layer. Rather than announcing only new assistants or branded AI features, Microsoft is describing changes to the operating environments where developers build software and where enterprise workloads run. That is an inference from the company’s sequencing of the WSL, Azure Linux 4.0 and Azure Container Linux announcements. (opensource.microsoft.com) ### What comes next? June 2 is the next date Microsoft has attached to the story. In its May 18 post, the company said Azure Container Linux would see a broader rollout at Microsoft Build on that date, and Build materials identify the conference as Microsoft’s flagship developer event for product announcements and technical sessions. (opensource.microsoft.com)