Microsoft is preparing an expansion of the Windows Azure virtual machine hosting technology that will let customers run either Windows or Linux virtual machines, as well as applications like SQL Server and SharePoint, according to Mary-Jo Foley at ZDNet.

Azure already has a "VM role" service in beta, letting customers deploy a Windows Server 2008 R2 image. This is similar to the type of VM hosting offered by Amazon's Elastic Compute Cloud, but much more limited—Azure hides much of the complexity of the operating system layer so developers can just focus on building applications.

Foley and her sources say Azure's current VM role is not persistent, meaning data is frequently lost. But a Community Technology Preview set to launch in spring of 2012 will fix this problem and add several other capabilities, including Linux hosting, according to Microsoft partners who spoke with Foley.

"What does this mean? Customers who want to run Windows or Linux 'durably' (i.e., without losing state) in VMs on Microsoft’s Azure platform-as-a-service platform will be able to do so," Foley wrote yesterday. "The new persistent VM support also will allow customers to run SQL Server or SharePoint Server in VMs, as well. And it will enable customers to more easily move existing apps to the Azure platform."

The Register noted last June that Microsoft was already testing Linux on Azure in its internal labs. Although Microsoft has often been at odds with the Linux community, it's a logical next step for the company, given that it has already worked on supporting Linux distributions on its Hyper-V virtualization software.