Microsoft has made downloadable ISO files available for the Fedora-derived distribution, Azure Linux 4. This allows users to install and test it outside of Azure for the first time.
The ISO files can be found on the project’s GitHub page. Azure Linux 4 is still in preview, and Microsoft recommends not using it in production environments. Both x86-64 and Arm64 images are offered.
The ISO files are not located in the general GitHub releases section, which mainly contains kernel builds. Instead, users will have to scroll down to the Using Azure Linux section and expand the ISO Installer subsection to find the images.
What is Azure Linux 4 designed for?
Azure Linux 4 is the successor to Azure Linux 3, which itself evolved from Microsoft’s earlier CBL-Mariner distribution. Unlike its predecessors, which were based on VMware Photon OS, Azure Linux 4 derives most of its packages and metadata from Fedora. As part of the change, Microsoft has moved configuration files from .spec to TOML format.
The current build identifies itself as “Four Beta” and runs on kernel 6.18 with systemd 258.4. Although it is derived from Fedora, Azure Linux 4 is not compatible with Fedora packages. Only two repositories are enabled by default:
- azurelinux-base
- azurelinux-microsoft, both hosted at packages.Microsoft.com/azurelinux/.
Available package selection is limited; Common tools such as less and htop are not included in the default installation and are not available for installation.
Azure Linux 4 is intended for use inside Azure virtual machines as part of automated deployment pipelines. The ISO version is primarily for testing and not for normal desktop or bare-metal installation.
The distribution does not come with a graphical desktop environment such as GNOME, and Microsoft has not announced plans to include it. Users who want a container-centric host should instead consider Azure Container Linux, Microsoft’s dedicated distribution for the Azure Kubernetes service. It is available separately on GitHub.
What to Expect from Preview ISO
Azure Linux 4 Preview has modest resource requirements. Its download size is 1 GB, it requires 1.1 GB of disk space, and 359 MB of RAM.
The installation process is straightforward using a simple command-line tool. By default, this sets up an LVM configuration with memory ballooning enabled.
This distribution can run on local Hyper-V virtual machines as well as inside Azure VMs, making it accessible to developers testing workloads before deploying them on Azure infrastructure.
Azure Linux 4 features the dnf package manager, which allows users to easily install additional software from available repositories. The distribution is not intended to be an immutable container host, meaning administrators have the flexibility to customize their installation for specific workloads within the range of available packages.
Microsoft has not released a detailed package roadmap, and the current repository selection reflects the preview state of the release.
How to try Azure Linux 4 locally
To download and try Azure Linux 4 locally, follow these steps:
- Go to the Azure Linux 4 GitHub page and scroll down to the section titled ‘Using Azure Linux’.
- Expand the ‘ISO Installer’ subsection and select the x86-64 or arm64 image depending on your needs.
- Create a virtual machine using Hyper-V, VirtualBox, VMware, or another hypervisor.
- Boot the VM from the ISO file you downloaded and proceed with the command-line installation prompts.
It’s important to note that Azure Linux 4 is still in preview, so it shouldn’t be used in a production environment. Preview status indicates that the distribution may contain bugs, incomplete package selection, or behavior that may change before it becomes generally available.
Microsoft’s published lifecycle documentation states that Azure Linux 4 will use the long-term support kernel and will receive monthly security updates. Some reports mention a two-year update cycle, but this has not been confirmed in the official lifecycle documentation.
Azure Linux 4 reflects Microsoft’s ongoing effort to bring its infrastructure toolchain in-house. The company moved LinkedIn to Azure Linux two years ago, ending its reliance on the now end-of-life CentOS Linux distribution.
Moving to Fedora as an upstream source with Azure Linux 4 reduces another dependency on VMware Photon OS, which was used in previous versions.
The change also supports a broader industry trend away from Broadcom’s VMware, with companies such as Tesco and T-Mobile also reported to be shifting their infrastructure away from VMware.
What users should know before installing
For users interested in trying out Azure Linux 4, the ISO download provides the first chance to test the distribution locally. It is recommended to download and test it only in a virtual machine environment.
Use it to evaluate packaging and configuration changes from older versions of Azure Linux.
Do not use it for production workloads or mission-critical systems. Keep an eye on the GitHub repository for updates as the preview moves toward general availability.
Microsoft has not announced any specific release date for Azure Linux 4. Users planning to migrate from Azure Linux 3 should follow the preview on GitHub and check Microsoft’s official documentation for guidance on when it will be ready for production.
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