Users running Linux on Microsoft Azure have now outpaced the number of users running Windows Server on Azure. The revelation comes from a Microsoft Linux kernel developer named Sasha Levin. Levin made the comment in a request that Microsoft be allowed to join a Linux security list. The use of Linux on Azure has grown exponentially over the last few years. Three and a half years ago Azure CTO Mark Russinovich said that one in four Azure instances was Linux.
In 2017 Microsoft said that 40% of Azure VMs were Linux-based. Last year, ZDNet was told by Scott Guthrie, Microsoft executive VP of the cloud and enterprise group, that about half Azure VMs were Linux. The increasing usage is no surprise; Linux is what most enterprise computing is done on. Linux is rising as Windows Server is declining; IDC's most recent Worldwide Operating Systems and Subsystems Market Share report in 2017 showed that Linux held 68% of the market and its share has grown since then.
Guthrie also stated that "Native Azure services are often running on Linux." One example given by Guthrie was Azure's Software Defined Network, which is based on Linux. There are currently eight Linux distros available on Azure, not counting Microsoft's own Azure Sphere using a custom Linux kernel.
Microsoft recently warned Azure users to patch Linux VMs to thwart the Exim Worm Security Threat. Azure users running Linux Exim email servers were vulnerable thanks to a critical security vulnerability in the Exim mail transport agent. About 3.5 million Linux servers were vulnerable to the Linux worm attack. Gamers were recently able to get Canonical to continue support for 32-bit Ubuntu Linux after the company announced that it would end support for 32-bit applications.