Microsoft has launched a preview of Azure Dedicated Host, a service that lets your Linux and Windows virtual machines live on a single-tenant physical server.

The move will spark a change in licensing terms in October which could have knock on effects for Microsoft customers hosting VMs with other cloud providers.

Many organisations will feel nervous running their VMs just “somewhere out there”, particularly from a security point of view. Having a dedicated host – rather than sharing the physical infrastructure with, well, who knows who exactly – will give them a heightened sense of security, as well as more control over exactly what setup their precious VM is running on.

Customers will be able to choose the underlying hardware, up to a point, including processor, the number of cores, and of course the Azure VMs they want to run. They also get control of maintenance issues, including OS updates.

Options listed as of today  today include a 2.3 GHz Intel Xeon E5-2673 v4 (Broadwell) processor with up to 64 VCPUs and 448GiB or RAM, or an Intel Xeon Platinum 8168 (Skylake) processor with up to 72 VCPUs and 144GiB of RAM.

In concert with the move, Microsoft said it was extending its Azure Hybrid Benefit to dedicated hosts, meaning users can use their existing on-prem “Windows Server and SQL Server licenses with Software Assurance or qualifying subscription licenses” and get a reduced rate on their Azure services. Microsoft is also expanding the Hybrid Benefit, to give “unlimited virtualization for Windows Server and SQL Server with Azure Dedicated Hosts.”

However, Microsoft said it would also be “updating licensing terms for Windows Server, SQL Server, and other Microsoft software products for dedicated cloud services” meaning from October, “new licenses purchased without Software Assurance and mobility rights cannot be used in dedicated hosting environments in Azure and certain other cloud service providers.”

Licensing terms are never simple, so if you think you might be affected, you might want to check out this page.

Likewise, if you’re using Red Hat or Suse Linux, you might want to double check what you’re covered for.

In other Azure-tinged news, Microsoft announced support for large test attachments in Azure pipelines. Microsoft said it had always featured support for test attachments, but that this had been extended to 100MB, meaning crash dumps and videos could now be supported. Some users will need to tweak their configurations to take advantage of the change, and details are here.