Microsoft Azure Hybrid Use Benefit (HUB) is a current offering from Microsoft that helps you take advantage of what you already own on-premises and allows you to spin up Windows virtual machines in Azure at a reduced rate.
The Azure Hybrid Use Benefit allows you to run Windows Server VMs in Azure while only get billed for the base compute rate. To take a brief step back… when you create a Windows virtual machine in Azure either from the Azure portal or programmatically via PowerShell, part of the hourly cost for the VM is for the compute ( V-cores, RAM, Hard Drive space, etc.) as well as for the Windows Licensing itself. So by taking advantage of the Hybrid Use Benefit, Microsoft allows you to use the Windows server licensing you already own with Software Assurance and use those towards covering cost of licensing for the Windows virtual machines in Azure.
You'll only be paying for the base compute of your virtual machine which effectively allows you to pay the same costs of spinning up a Linux virtual machine in Azure. Savings will vary depending on the series of VM you create but as shown in the graphic below you can realize savings as much as 41%.
Each Windows Server Standard or Datacenter with SA license will permit you to run either:
Windows Server Standard with SA can only be used on a single server – meaning, you may use the Windows server license on-premises or in Azure, but not both at the same time.
Windows Server Datacenter with SA allows you to continue using the unlimited virtualization benefits on each licensed host on-premises but you can also take advantage and run a Windows virtual machine in Azure as well off the same license.
You will need to create a VHD that contains your base Windows Serer build and load it into Azure. There are some pre-requisites and other steps to follow which you can find more details on here.
Run Windows 10 on Azure.
Recently, Microsoft added the benefit for Enterprise Agreement customers with qualifying licenses to now use the Windows 10 Enterprise Preview [HUB] image within the Azure Marketplace to stand up and use a full instance of
Windows 10 Enterprise running on a virtual machine in Azure.
You can find the Microsoft Azure HUB Windows 10 Preview terms below:
Only Enterprise customers with Windows 10 Enterprise E3/E5 per user or Windows VDA per user (User Subscription Licenses or Add-on User Subscription Licenses) (“Qualifying Licenses”) are eligible to use Microsoft Azure Hybrid Use Benefit for Windows 10 (“Azure HUB for Windows 10”). Under this preview, users to whom a customer has assigned a Qualifying License may deploy and use Windows 10 images provided in the Azure virtual machine gallery (images designated as Azure HUB for Windows 10 images) on Microsoft Azure. Each such user may use up to four instances of the Windows 10 software subject to (i) the terms of the Windows Desktop Operating System Product Entry in then-current Microsoft Volume Licensing Product Terms and these preview terms, and (ii) the requirement that each user is managed through Azure Active Directory. Ongoing use of the Windows 10 software under Azure HUB for Windows 10 is permitted under the same terms until the end of the fourth full calendar month following the declaration of next Current Branch for Business following the Windows 10 Anniversary Update (1607). In the event of any conflict between the terms of the Windows Desktop Operating System Product Entry and these preview terms, these preview terms prevail.