Windows News and info 15th Anniversary 2009-2024
Other Operating Systems => Linux, gOS, Harmony OS, Moblin, Ubuntu, OpenSuse => Topic started by: javajolt on June 29, 2026, 04:03:15 AM
-
Now ships its own free distro that’s nothing like Ubuntu or Fedora
(http://iili.io/CR6gKYP.jpg)
Azure Linux 4.0 is Microsoft's own Linux distribution, built for cloud servers and containers on Azure.
Twenty-five years ago, Microsoft’s CEO, Steve Ballmer, called “Linux a cancer that attaches itself in an intellectual property sense to everything it touches.” At Build 2026 in June, the same company shipped its own Linux distribution to the public. Well, at least the product is not a joke!
Azure Linux 4.0 is a real, open-source Linux distribution maintained entirely by Microsoft. It is derived from Fedora, runs on Azure virtual machines, and has already been powering Microsoft’s own infrastructure for years without most people knowing its existence.
What Build 2026 changed is that it is now a free product for anyone to download and use. However, it’s completely different from the other popular Linux Distros like Ubuntu or Mint.
(http://iili.io/CR6PCSp.png)
What is a Linux distribution, and where Azure Linux 4.0 fits
Linux itself is just the kernel, the core layer that manages hardware, memory, and processes.
A distribution, or distro, takes that kernel and packages it with everything else an operating system needs, including a package manager to install software, system tools, default configurations, a support structure, and a graphical user interface that helps regular folk use the OS.
Ubuntu, Fedora, Debian, Red Hat Enterprise Linux, and Arch Linux are all distributions built on the same Linux kernel, each with different goals and audiences.
(http://iili.io/CR6sIGs.png)
Azure Linux 4.0 is Microsoft’s entry into this list. It is built from Fedora 43 as its upstream base, meaning it uses the same RPM package format, package lineage, and ecosystem as Fedora and Red Hat. The difference is that Microsoft curates the package set, maintains the security patches, and tunes it specifically for running cloud workloads on Azure.
(http://iili.io/CR6LKiu.png)
How Azure Linux started and what changed with version 4.0
Azure Linux started in 2019 under the name CBL-Mariner, short for Common Base Linux Mariner, as an internal Microsoft project to build a lightweight, secure OS for Azure’s own infrastructure. By 2022, it was already powering production workloads at scale, including AKS (Azure Kubernetes Service), Azure SQL, and Azure Cosmos DB.
LinkedIn migrated its entire infrastructure to Azure Linux 3 (http://www.linkedin.com/blog/engineering/architecture/navigating-the-transition-adopting-azure-linux-as-linkedins-operatingsystem), and Databricks moved more than 100,000 VMs and over a million CPU cores to it with zero customer-facing incidents. Microsoft renamed it Azure Linux in March 2024.
(http://iili.io/CR6tuxS.png)
Versions 1 through 3 were assembled package by package by Microsoft engineers writing their own spec files. Version 4.0 (http://learn.microsoft.com/en-us/azure/azure-linux/whats-new-azure-linux-4) changes the foundation. Instead of maintaining every component from scratch, Microsoft now builds Azure Linux as a set of declarative overlays on top of a Fedora 43 snapshot, with every deviation from the upstream documented in the public GitHub repository. Anyone can inspect what Microsoft changed and why.
(http://iili.io/CR6pqhl.png)
The previous version also used tdnf, a stripped-down package manager Microsoft built itself. Version 4.0 switches to dnf5, the same package manager Fedora and Red Hat use, which is faster, uses less memory, and makes the distribution behave more predictably for anyone already familiar with Red Hat.
Officially announced at the Open Source Summit North America on May 18 (http://opensource.microsoft.com/blog/2026/05/18/from-open-source-to-agentic-systems-microsoft-at-open-source-summit-north-america-2026/), 2026, and launched into public preview at Build 2026 on June 2 (http://techcommunity.microsoft.com/blog/linuxandopensourceblog/announcing-azure-linux-4-0-purpose-built-for-azure-now-in-public-preview/4524267), Azure Linux 4.0 is now available on Azure VMs and VM Scale Sets, with AKS support and a WSL distribution coming shortly after.
How Azure Linux 4.0 differs from Ubuntu, Fedora, and RHEL
The most important thing to understand about Azure Linux 4.0 is what it is not. It is not a general-purpose distribution like Ubuntu or Fedora that you install on a laptop, set up a desktop, and use as your daily driver. There is no graphical interface. There is no audio stack. There is no desktop environment. The base image does not even ship with a pager like less (http://en.wikipedia.org/wiki/Less_(Unix)). It installs only what cloud and server workloads need, nothing more.
(http://iili.io/CRPJCAu.jpg)
Ubuntu
Azure Linux 4.0 is entirely text-based, with no graphical setup wizard as you would find on Fedora or Ubuntu. Creating a user account is optional during setup and easy to miss, which would leave you unable to log in.
Once running, it drops you directly to a console with Bash as the default shell. There is no desktop waiting on the other side. To try something similar yourself, download the ISO from the Azure Linux GitHub repository (http://github.com/microsoft/azurelinux), spin up a VirtualBox or Hyper-V virtual machine, and point it at the ISO. Do not expect a Fedora-style GUI installer or any desktop components.
The minimal design is the point. A smaller package footprint means a smaller attack surface and fewer vulnerabilities to patch each month. For server and container workloads, you want an OS that is invisible, predictable, and fast.
Ubuntu Server, Fedora Server, and Red Hat Enterprise Linux are also stripped-down compared to their desktop variants, but they still carry significantly more than Azure Linux does by default. And critically, those distributions are supported and designed to run anywhere, including on-premises, on other clouds, on physical hardware. Azure Linux 4.0 is explicitly a cloud-only distribution. Running it outside Azure is technically possible, but entirely unsupported by Microsoft.
(http://iili.io/CRPCP5l.jpg)
What is inside Azure Linux 4.0
If you’re curious about the technical stack, here is what ships with the current public preview:
The kernel is Linux 6.18 LTS, tuned specifically for Azure with optimized Hyper-V integration and GPU and AI accelerator support. The package manager is dnf5, a complete rewrite of the older DNF in C++ rather than Python, which makes it noticeably faster on dependency resolution.
The base C library is glibc 2.42, and the init system is systemd 258. Python 3.14 is included with its new JIT compiler. OpenSSL 3.5 ships with post-quantum cryptography support, covering the CRYSTALS-Kyber and CRYSTALS-Dilithium algorithms that NIST standardized, which is a meaningful differentiator for enterprise customers with regulatory requirements.
FIPS 140-3 certification is still in progress and will not be available until general availability. For government, financial services, and healthcare workloads where FIPS compliance is a hard requirement, Azure Linux 4.0 is not yet a drop-in replacement for certified RHEL builds, though Microsoft expects to close that gap before general availability later in 2026.
(http://iili.io/CRPI4NR.jpg)
Azure Container Linux, the companion product
Azure Container Linux is Microsoft’s second Linux product from Build 2026, and it is easy to confuse with Azure Linux 4.0 since they share the same kernel and security update schedule.
The main difference is that Azure Container Linux is immutable. The OS ships as a read-only image, so you cannot install packages, change settings, or make any changes on a running system. When an update arrives, Windows swaps the entire image out for a new one, with an automatic rollback if something breaks. It has been running quietly underneath Azure’s Kubernetes service (AKS) since 2023, and version 4.0 makes it available as a standalone product for the first time.
(http://iili.io/CRPAx6P.jpg)
Why Microsoft built its own Linux distribution
Linux is now the most popular operating system on Azure. More Linux instances run on Microsoft’s own cloud than Windows Server instances. And the Linux running there, Ubuntu, RHEL, SUSE, and Debian, is maintained by other companies. Every time a customer runs Red Hat on Azure, Red Hat collects the support subscription revenue. Microsoft provides the infrastructure but splits the OS revenue.
If Microsoft can get customers to standardize on its own distribution with Azure Linux, it controls the entire stack and the supply chain end to end. Every package is cryptographically signed, and Software Bill of Materials (SBOM) documents are published for every release. For enterprise teams in regulated industries, the ability to hold a single vendor accountable for the entire OS layer is a serious selling point.
(http://iili.io/CRPRrgt.png)
Source: GitHub
It is the same reason Amazon built Amazon Linux, and Google built Container-Optimized OS. Azure Linux is Microsoft joining a list that every major cloud provider is already on.
Also, Microsoft is explicitly marketing Azure Linux as the distribution you can run in WSL during development and then deploy to Azure in production, eliminating the environment mismatch problem where code that works locally breaks in the cloud. It gets more compelling once WSL Containers (http://www.windowslatest.com/2026/06/28/microsoft-denies-wsl-3-exists-reveals-windows-11s-wsl-containers-ship-next-week/) ships, because developers would be able to build, run, and test Linux containers locally using WSL and deploy to Azure Linux in production, all without leaving Windows.
(http://iili.io/CRP7jDJ.jpg)
Should you care about Azure Linux if you are not a cloud developer
Probably not yet, and that is fine. Azure Linux 4.0 is in public preview, carries a strict not-for-production warning, and is explicitly designed for cloud server and container workloads on Azure. If you run Ubuntu on your PC, deploy apps on RHEL, or use Fedora as a daily driver, nothing about Azure Linux displaces any of that.
What it does show is that Microsoft is now an active maintainer of a real distribution that runs production workloads for LinkedIn and Databricks, and it is now offering that distribution as a first-class option to anyone.
source (http://www.windowslatest.com/2026/06/29/microsoft-called-linux-a-cancer-now-ships-its-own-free-distro-thats-nothing-like-ubuntu-or-fedora/)