These days, Microsoft puts a lot of effort into making Linux run as smoothly as possible on Azure, according with a talk given earlier this year at the Linux Foundation Open Source Summit.
The talk was given by two Microsoft Azure Linux Platforms Group program managers, Jack Aboutboul and Krum Kashan. 
"Linux is the #1 operating system on Azure today," Aboutoul said. And everything must be supported in the way Microsoft users expect. Thus was born the need for Microsoft's Linux Platforms Group, which provides Linux support to internal customers as well as Azure customers. Today, engineers said, Microsoft knows better than anyone how to make Linux work at hyperscale.
Today, there are hundreds of Azure-based services running on Linux, including Azure Kubernetes Services (AKS), OpenAI, HDInsight, and many other database services.
"A lot of the infrastructure that powers everything runs on Linux," Aboutoul said. "It's different Linux distributions running everywhere." To run these services, Microsoft maintains its own core, Azure Linux, and in 2023 the company released its own Linux distribution, azure linux. But Azure Linux is a small part of all the other Linux distributions running on Azure, and Microsoft has to work with all of them to support them.
In total, there are about 20.000 third-party Software as a Service (SaaS) packages in the Azure marketplace based on some Linux distribution. The company maintains a set of approved Linux distributions, which include the operating Red Hat Enterprise Linux, Debian, Flatcar (Container Linux), Suse, Canonical and Oracle Linux and CentOS (managed by OpenLogic, not Red Hat).
In total, the company has about 1.000 images from these approved partners alone. Many of the distributions have multiple images (Suse has a normal one and another for high-performance computers, for example).
So now we can say that Azure was a cloud platform dedicated to Windows.
The distribution is called “SUSE” with capital letters, not Suse. It is not a vocabulary word but an acronym. Like "AI" is never written with small letters because it is an acronym, otherwise it would be written Ai.
The distribution is called “SUSE” with capital letters, not Suse. It is not a vocabulary word but an acronym. Like "AI" is never written with small letters because it is an acronym, otherwise it would be written Ai.