Microsoft Releases Its Own Linux Distribution Finally

After two years of internal use and running in public preview since October 2022, Microsoft has finally officially released its Azure Linux distribution to the public a few days ago.

Microsoft’s bespoke open source distribution “allows us to have a very clear, very assertive Azure focus and tune the components of the distribution to what we need to support container hosts,” said Jim Perrin, principal program manager for Azure Linux at Microsoft . And try to keep dependencies, extra packages, whatnot to a minimum”.

According to the introduction , Azure Linux is an open source container host operating system for Azure Kubernetes Service (AKS), optimized for Azure, and designed to make it easier for developers to use Microsoft tools to deploy and manage container workloads. 

Azure Linux Container Host provides reliability and consistency from cloud to edge across AKS, AKS-HCI and Arc products. 

You can deploy an Azure Linux node pool in a new cluster, add an Azure Linux node pool to an existing Ubuntu cluster, or migrate your Ubuntu nodes to Azure Linux nodes.

The Azure Linux distribution is derived from the CBL-Mariner project, where CBL stands for Common Base Linux. Microsoft started the CBL-Mariner project because it needed an in-house Linux distribution and a consistent platform for the myriad workloads engineers were running on Azure, Perrin said.

He explained in the Build Q&A session that Azure Linux is “a commercially supported product of CBL Mariner Linux.” But it also has limited commercial support, as the operating system’s current primary purpose is to run as a container host for Azure Kubernetes Service (AKS). It’s optimized for Microsoft’s Windows Hyper-V hypervisor and runs inside a virtual machine, with support for both x86 and Arm.

Microsoft emphasized that Azure Linux is “very focused on Azure” and intentionally includes “the fundamentals of running a Kubernetes cluster.” That said, other product teams may build on it for other purposes, the .NET team being an example.

 Some container workloads use Azure Linux, but Microsoft’s official support is limited to the host.

Azure Linux is a Linux distribution developed by Microsoft itself, and the company has not chosen to fork open source distributions such as Fedora or CentOS. In this regard  , Perrin said that there is a certain reason for the influence of the famous saying that former Microsoft CEO Steve Ballmer once said-“Linux is a cancer”.

“Azure Linux is its own distribution. We didn’t fork Fedora or anything like that. We borrowed code from them, and it’s an RPM-based distribution. The reason we chose not to fork a different distribution… Microsoft has some kind of history with Linux… I think Ballmer’s quote is from 2001 but a lot of the sentiment is still there even today. We didn’t choose to start with an existing distro and fork it as needed Part of it is, we don’t want to be seen as embracing and extending again. We want to build from the ground up, which can be customized to suit our needs…we’re grabbing one of our itch and offering a solution to the community.”

Perrin also believes that its Azure Linux is comparable to Amazon Linux, but overall the two are quite different. 

Amazon Linux is designed for customers to install on their virtual machines, Azure Linux is not currently. 

Also, Amazon Linux 2023 is somewhat related to Fedora; although the AWS documentation states that “the GA release of AL2023 is not directly compared to any specific Fedora release, it “includes components from Fedora 34, 35, and 36.”