After using Azure Linux internally for two years and running it in public preview since October 2022, Microsoft finally made its Azure Linux distribution available this week.
Azure Linux is an open source container host operating system for Azure Kubernetes Service (AKS) that is optimized for Azure and aims to make it easier for you to use Microsoft tools to deploy and manage container workloads. This is basically: Azure Linux is designed to be deployed in the cloud and to run multiple containers.
The Azure Linux distribution comes from the IT Giant's CBL-Mariner project, CBL stands for Common Base Linux. Microsoft started CBL-Mariner because it needed an internal Linux distribution and a consistent platform for the many workloads engineers were running on Azure, according to Jim Perrin, principal program manager for Microsoft Azure Linux.
The open source distribution customized by Microsoft”it allows us to have a very defined, very questionable Azure focus and tune the components of the distribution to be exactly what we need to support a container host and try to keep dependencies, extraneous packages, stuff like that to a minimum“, Perrin said during a Q&A session at Build 2023, where Redmond announced the general availability of Azure Linux.
The "very questionable" part of this means that Azure Linux's primary role is as a container host for AKS. It's optimized for Microsoft's Hyper-V Windows hypervisor and runs in a virtual machine (VM), supporting both x86 and ARM, he said.
Optimized for Azure, but with some scope. That said, it has some general applicability.
"Azure Linux container host provides reliability and consistency from cloud to edge through AKS, AKS-HCI and Arc products“, Microsoft wrote on a support page. “You can deploy Azure Linux node pools in a new cluster, add Azure Linux node pools to your existing Ubuntu clusters, or migrate your Ubuntu nodes to Azure Linux nodes."
Lightness of deployment is a key point, Perrin said. The small footprint includes a 400MB core image and 300 packages, which Microsoft said works well for both performance and security.
Security was a focus, Perrin said in a blog post, noting that all updates to the OS are run through Azure validation testing and the test suite is constantly updated.
"Also, since there are far fewer packages on the container host, the volume of required security patches is lower, and these issues are patched promptly", he wrote. "We closely monitor and fully curate the software supply chain, which allows for greater quality assurance and end-to-end resiliency. "
These were all good reasons for Microsoft to develop its own Linux distribution rather than adapting one from Fedora, CentOS, or other commercially available choices. The company borrowed code from some of them but Redmond stopped short of forking distributions.
"Azure Linux is its own separate distribution"He said.
About that little comment… History also played a role in Microsoft's decision to go relatively on its own, Perrin said, recalling a 2001 quote from then-CEO Steve Ballmer:
Linux is a cancer.
"Microsoft has something of a history with Linux“Perrin said during the Q&A. Those quotes and that animosity are old enough to drink now… but a lot of the sentiment still lingers today, so part of the reason we didn't choose to start with a distribution and fork it for our needs is that we didn't want to be seen as if we were doing the hug and extension thing again. We didn't want to awaken any of that.
"We thought, build it from scratch. We can adapt it to our needs. We're making changes as we need to, and frankly, that's kind of what the Linux ecosystem is. We're scratching an itch we had and offering it to the community."
A number of tech players have signed up as Microsoft partners for Azure Linux, including Tenable, DataDog, HashiCorp, and Dynatrace.
Palo Alto Networks is supporting Azure Linux as an AKS container host through its Prisma Cloud, said Derek Rogerson, senior product marketing manager at the network security vendor, noting that the smaller image size means a larger one.
"The result for customers is a reduced attack surface and a beneficial elimination of time consuming patching and maintenance that are no longer required due to the removal of unnecessary packagesRogerson wrote in a blog post.
Kubernetes Applications for Sale in Marketplace Also at Build, Microsoft announced that Kubernetes applications, a collection of third-party open source offerings for the AKS platform, are generally available in the Azure Marketplace.
Kubernetes applications, which went into public preview in October 2022, enable one-click deployments, CI/CD automation, automated lifecycle management, and support. There are also flexible consumption options.
Available apps are verified and certified by Microsoft and scanned for vulnerabilities, a necessary step at a time when the number of supply chain attacks continues to increase.
This all comes about a week after Azure Container Storage, a fully managed service for creating and managing block storage volumes for containers, went into public preview. The software-engineered storage service will allow enterprises to run production workloads on AKS, according to Microsoft. ®
Microsoft's entry into the Linux world with Azure Linux raises a number of intriguing questions. Will Microsoft be able to undermine the dominance of established companies like RedHat in the Linux sector? This step marks a significant turning point for Microsoft, known for its Windows operating system. However, it remains to be seen whether its custom Linux distribution will have the impact and reception the company is hoping for. Also, how much will this move the boat in the cloud vendor landscape?