Microsoft Finally Lets Azure Linux 4 Run Anywhere
Here's something that should matter to anyone running hybrid infrastructure: Microsoft has published downloadable ISO files for Azure Linux 4 on the project's GitHub page. For the first time, you can spin this Fedora-derived server distro up in a local VM — Hyper-V included — without touching the Azure Marketplace.
It's still preview. Still not production-ready. But the fact that Microsoft is making it installable outside its own cloud tells you something about where they're heading. The distro's no longer a walled garden.
The ISOs live in an unexpected spot on the GitHub repo. Don't look under Releases — that section only has kernel builds. Scroll down to "Using Azure Linux," expand the "ISO Installer" subsection, and you'll find both x86-64 and Arm64 images. That's a minor UX quirk, but one that'll probably bite someone before long.
The download itself is a modest 1 GB. Installation takes about 1.1 GB of disk and 359 MB of RAM. Tiny by modern standards, which tells you this is purpose-built for VMs and containers, not your average workstation.
What's Actually in the Box
Azure Linux 4 reports itself as "Four Beta" and runs kernel 6.18 with systemd 258.4. It derives most of its package sources and packaging metadata from Fedora, but don't mistake it for a rebadged Fedora Server. The two default repositories — azurelinux-base and azurelinux-microsoft, both hosted on packages.microsoft.com/azurelinux/ — contain a surprisingly sparse selection. We were genuinely surprised to find the less command missing from a base install, and htop wasn't even available to pull in.
You do get dnf, which is the right call. This isn't some immutable container host — Microsoft has Azure Container Linux for that, a separate project aimed at AKS workloads. Azure Linux 4 is a full-featured server OS, just one that's still early in its lifecycle. No GNOME. No desktop environment of any kind. The installer is a basic command-line tool that sets up LVM by default with memory ballooning enabled.
This is a distro designed to be provisioned automatically by deployment pipelines. The ISO exists for testing. That's it. If you're looking to replace Windows Server or run this as a general-purpose workstation OS, look elsewhere.
From CBL-Mariner to Fedora: Why the Upstream Shift Matters
Azure Linux 4 is the successor to Microsoft's older CBL-Mariner distro, which we covered back in 2022. It went through a transformation in 2024 when it became Azure Linux 3, and now version 4 has fully committed to Fedora as its upstream. The configuration story has shifted too — TOML files now handle what used to be .spec files inherited from VMware Photon OS.
This upstream migration is strategically significant. Two years ago, Microsoft moved LinkedIn onto Azure Linux specifically to eliminate its dependency on CentOS Linux after that distribution went end-of-life, replacing it with the rather different CentOS Stream. Now, by moving to Fedora as its base, Microsoft is cutting another external dependency — this time on the aging VMware Photon OS.
The timing isn't coincidental. Other VMware customers are also moving away from Broadcom following the acquisition, including international supermarket chain Tesco and telco giant T-Mobile. Microsoft's distro strategy is clearly part of a broader pattern: bring critical infrastructure in-house, reduce vendor lock-in from the outside, and control your own patching cadence.
What This Means for Hybrid Cloud Operators
If you're running workloads that span Azure and on-premises datacenters, the ability to test Azure Linux 4 locally is genuinely useful. You can validate application compatibility, check tooling integration, and stress-test deployment pipelines without burning Azure credits or waiting on marketplace image propagation.
The two-repository model means the package surface area is intentionally narrow right now. That's both a strength and a limitation. It keeps the attack surface small and the update footprint tight — good for security-conscious ops teams. But it also means you'll be waiting on Microsoft to ship packages you might take for granted in other distros.
The published lifecycle says LTS kernels with monthly security updates. There are reports of a two-year update cycle, but that figure doesn't appear in any official documentation yet. Take it with a grain of salt until Microsoft formalizes it.
The bottom line: Azure Linux 4 is moving from "Azure-only experiment" to "installable anywhere for testing." Production readiness is still a ways off, but the direction is clear. Microsoft wants this distro to be a real option for hybrid cloud operators who need consistency between their Azure and on-premises environments.
The Bigger Picture: Microsoft's Linux Strategy in Context
This ISO release doesn't happen in a vacuum. Microsoft has been steadily building out its Linux credentials for over a decade, and Azure Linux 4 represents the latest evolution of that effort. The company now runs its own cloud infrastructure on Linux-derived operating systems, manages some of the world's largest Linux deployments through Azure, and contributes actively to the kernel and broader open-source ecosystem.
The move away from VMware Photon OS is particularly telling. Photon was always a bit of an outlier — a distro built from scratch for virtualization workloads, with its own package management and configuration approach. By adopting Fedora's proven packaging infrastructure, Microsoft gains access to a massive existing ecosystem of packages, tools, and documentation. Engineers who already know Fedora can pick up Azure Linux with minimal friction.
There's also an implicit message here about Microsoft's relationship with Red Hat and the broader Linux ecosystem. Fedora is community-driven, with Red Hat serving as the primary corporate sponsor. By building Azure Linux on top of Fedora rather than RHEL, Microsoft maintains more independence in its release cadence and feature decisions. It's a pragmatic choice that acknowledges Fedora's role as the innovation frontier for enterprise Linux.
Whether Azure Linux 4 ever becomes a serious alternative to RHEL or SUSE in enterprise environments remains to be seen. But the foundation is being laid, and the ability to test it locally is an important step toward that goal.