Public preview: Azure Linux 4.0 for Azure Virtual Machines and VM Scale Sets

Azure Linux 4.0, Microsoft's first-party Linux distribution purpose-built for Azure, is now available in public preview for Azure Virtual Machines and VM Scale Sets. It brings a modernized stack — including Linux kernel 6.18 LTS, dnf5 package manager, glibc 2.42, OpenSSL 3.5, and Python 3.14 — optimized for Azure compute, storage, and networking. It delivers faster VM startup and provisioning with a reduced package footprint and a security-first design.

Key highlights:

• Azure-tuned kernel — Linux 6.18 LTS with improved Hyper-V integration, GPU/AI accelerator support, and new hardware drivers
• Secure by default — Secure Boot, Trusted Launch, SELinux support, kernel hardening, and SBOMs published with target SLSA Level 3
• Minimal footprint — Ships only the packages required for cloud workloads, reducing attack surface from day one
• No additional OS licensing cost — Included with Azure compute; no separate OS licensing fees or support contracts
• Microsoft-owned supply chain — From kernel to CVE response, enabling fast-track Critical/High CVE patches with monthly security updates
• Predictable lifecycle —full support with LTS kernel and annual HWE kernel updates for new hardware platforms
• Container images — Base, and distroless images available on Microsoft Container Registry (MCR)

Learn more:

• Azure Linux 4.0 Build blog post
• Azure Linux on GitHub
• Release notes