Microsoft has officially unveiled Azure Linux 4.0, the latest version of its open-source Linux distribution designed for cloud infrastructure, enterprise workloads, and modern data centers. Formerly known as CBL-Mariner, Azure Linux has powered Microsoft’s internal cloud services for years, but version 4.0 marks its biggest evolution yet by becoming a general-purpose server operating system that organizations can deploy both inside and outside Azure.
The release introduces updated core components, expanded hardware support, a predictable long-term lifecycle, and improved compatibility for enterprise environments, reinforcing Microsoft’s growing investment in the Linux ecosystem.
A New Chapter for Azure Linux
Azure Linux began as Microsoft’s internal operating system for Azure services, containers, and cloud infrastructure. Over time, it evolved into the foundation for many Azure-hosted workloads.
With Azure Linux 4.0, Microsoft is positioning the distribution as a broader enterprise Linux platform rather than one limited to Azure infrastructure. The operating system is now available through Azure virtual machine images, container images, and downloadable ISO files for testing and deployment in a wider range of environments.
Built for Enterprise and Cloud Workloads
Unlike desktop-focused Linux distributions, Azure Linux is optimized for infrastructure, virtualization, containers, and cloud-native applications.
Typical deployment scenarios include:
- Cloud virtual machines
- Kubernetes clusters
- Container hosts
- AI infrastructure
- Edge computing
- Enterprise servers
Microsoft has designed the distribution to provide a consistent operating system foundation across Azure services while remaining suitable for on-premises deployments.
Updated Core Components
Azure Linux 4.0 modernizes much of the operating system’s software stack.
Highlights include:
- Linux Kernel 7.0
- glibc 2.42
- OpenSSL 3.5
- Python 3.13
- OpenSSH 10
- dnf5 as the default package manager
These updates improve hardware compatibility, application support, security, and overall system performance while providing developers with a more current software platform.
Security Remains a Primary Focus
Security continues to be one of Azure Linux’s defining characteristics.
Version 4.0 includes: