Licensing Windows Server on GCP


Licenses that are eligible for License Mobility[1] and covered with active Software Assurance (SA), can be deployed to third party shared datacenter environments like GCP shared tenancy.

Google, as an authorized ‘License Mobility through Software Assurance’ Partner,[2] can enable License Mobility on eligible Microsoft Server products on GCP.

The list of eligible server products for License Mobility are defined in the Microsoft Product Terms, including but not limited to: Microsoft SQL Server, Microsoft Exchange, Microsoft Skype for Business, Microsoft SharePoint, Microsoft System Center, RDS CAL, BizTalk Server and eligible Dynamics products. (In this document these products will be collectively referred to as Microsoft Application Servers).

Sole-tenant nodes are physical Compute Engine servers that are dedicated for hosting VM instances for your specific project. Normally, VM instances run on physical hosts that may be shared by many customers. With sole-tenant nodes, the host is dedicated to your business.[3]

GCP sole-tenant is a dedicated server that is physically isolated for use by a single customer. All hardware resources and storage will remain fully dedicated to your use for the term of your subscription.

Each sole-tenant node is associated with one physical server, and is the only node running on that server. You can manually select the location to launch your instances to a specific dedicated host. Node affinity determine which nodes your VM instances use as a host system. You can configure additional affinity labels so that your instances run only on the node groups that you want or share nodes only with instances of the same affinity type. Affinity labels keep sensitive data together on specific node groups and separate from your other node groups and other VM instances running on Compute Engine. It provides you with visibility and control to meet regulatory and compliance requirements.

In this case, the outsourcing documentation within the Microsoft Product Terms will apply[4] and licenses that are not eligible for License Mobility or that do not have active Software Assurance, can be deployed to GCP sole-tenant nodes.

Windows Server

There are two available options to deploy Windows Server on GCP: virtual machine instances and sole-tenant nodes.

Virtual Machine instances: Windows Server per-core licenses are included in the cost of the Windows Server instances purchased on-demand. Whether you bring your existing Windows Server images to run on VM instances or use the pre-built images available in GCP, the license is included in the cost, and Windows Server CALs are not required.

Sole-tenant nodes: GCP provides the option to bring your own licensing (BYOL) for Windows Server with your own images to GCP sole-tenant and remain compliant for Microsoft licensing.

A sole-tenant from GCP is a dedicated single-tenant host that is fully dedicated for your use. GCP will not support two customers to share the same set of resources, such as hardware or storage for the term of your subscription. In this case, the outsourcing wording within the Microsoft Product Terms applies.[5]

Windows Server does not have ‘License Mobility’ rights to enable bring your own licenses to a multi-tenant environment, so we only recommend deployment on our sole-tenant offering. Windows Server licenses can only be assigned to physically dedicated sole-tenant hosts.

License Re-Assignment

Each sole-tenant node is associated with one physical server dedicated to hosting your VM instances. You can control VM placement to launch your instances to a dedicated host, and instance affinity will allow specific node affinities between your nodes and VM instances. This will enable you to control VM instance placement to satisfy the restriction of license re-assignment once every 90 days.[6]

The license re-assignment rule will apply to your licensing of Windows Server unless there is a permanent hardware failure. In this scenario when there is permanent failure of hardware[7] components, the sole-tenant node that is hosting the VM instances will use live migration8 to move the VM instances to replacement host hardware automatically. If there is complete hardware failure, the VM will crash and restart automatically and a host-error is logged.

License Reporting

Windows Server is licensed by the physical cores on each host. GCP provides visibility into the number of physical processors and physical cores, and number of Windows VMs running on the host machine to keep track of how your Windows Server VMs use the resources of the dedicated host.

If you elect to bring your own licensing for Windows Server, then this would also require Windows Server CALs. Your organization may already be licensed for Windows Server CALs through Core CAL, Enterprise CAL, or Office 365 license packages such as Microsoft 365 E3, and Microsoft 365 E5.

You may also require additional licenses for Windows Server Rights Management Services (RMS) CALs, or Remote Desktop Services (RDS) CALs.

Remote Desktop Services (RDS) CALs will be required should a licensed user, or licensed devices, directly or indirectly access RDS functionality, including Remote Desktop Session Host (RDSH), or as a Connection Broker.

If you require more than two connections to Remote Desktop for administration, you may require additional licenses for Remote Desktop Services (RDS) CALs. Please work with your preferred Licensing Solution Provider (LSP) to purchase additional RDS CALs as required.

You can use any number of VMs instantiated as Windows Server (without Hyper-V) Containers on the Licensed Server. Each Hyper-V isolation instance used to host one or more Windows Server Container is considered one VM for licensing purposes.

You are responsible for all reporting and compliance obligations under your volume licensing agreement regardless of the physical location of the hardware upon which the software is used.

Please refer to your Microsoft Volume Agreement and binding contractual documents for additional information on reporting your licensing requirements to Microsoft.

Licensing with Datacenter Edition

Sole-tenant is a dedicated host offering that provides a commercial benefit in licensing your sole-tenant(s) with Windows Server Datacenter Edition or Core Infrastructure Suite (CIS) Datacenter Edition. This will support an unlimited number9 of Windows Server VM instances to run on the licensed host. This approach can be advantageous when you have a higher number of Windows Server VM instances running on the sole-tenant node.

Software Assurance

It is not required to have Software Assurance to bring your own Windows Server licenses to the GCP sole-tenant. However, it may be beneficial to maintain active Software Assurance to enable access to ‘New Version Rights’ as new software versions are released10 and to leverage Software Assurance Benefits.

Although Software Assurance is not required to bring your own Windows Server licenses to a dedicated sole-tenant, you will be able to leverage your legacy licenses for prior software versions. The use rights for the originally licensed version will still apply.

GCP sole-tenant is ideal for leveraging licenses where active Software Assurance has not been maintained, or licenses were purchased without Software Assurance. Additionally, sole-tenant will support per-core, per processor, and server with CAL based license models to take advantage of your prior software licensing investments.

Right to Run Prior Versions

Microsoft ‘downgrade rights’ are available for Windows Server and support downgrade to any prior version of the same product.11 The use rights for the licensed version will still apply.

For example, you can purchase Windows Server 2019 and downgrade to an earlier version of the product, such as Windows Server 2016.

GCP will allow you to run versions that are approaching end of support or have reached end of support. In this case you should work with Microsoft to ensure your Windows Servers are covered with Extended Security Updates (ESU) available for purchase separately from Microsoft. Alternatively, you can opt to upgrade to the latest supported version.

If you have purchased Windows Server instances on-demand, GCP will not maintain images in the gallery after the end of support date. It is therefore recommended to download any required images and retain them in a private repository prior to end of support, or upgrade to the latest supported version.

[1] The GCP shared tenancy service description conforms with the requirements for “License Mobility” as defined in the Microsoft Product Terms, February 2019, page 67 of 112.

[2] GCP is an authorized “License Mobility through Software Assurance Partner” as described in the Microsoft Product Terms, February 2019, page 70 of 112.

[3] The sole-tenant service description is available here.

[4] Please refer to Section 8. “Outsourcing Software Management” in the Microsoft Product Terms, February 2019, page 6 of 112.

[5] Please refer to Section 8. “Outsourcing Software Management” in the Microsoft Product Terms, February 2019, page 6 of 112.

[6] Please refer to Section 9 “License Assignment and Re-Assignment” in the Microsoft Product Terms, February 2019, page 6 of 112.

[7] Please refer to Section 9 “License Assignment and Re-Assignment” in the Microsoft Product Terms, February 2019, page 6 of 112.

8 The description of live migration available for Compute Engine is available here.

9 Please refer to ‘Server Licenses (per core)’ – Item 3 of the Microsoft Product Terms, February 2019, page 9 of 112.

10 Microsoft confer ‘New Version Rights’ in the Microsoft Product Terms, February 2019, page 78 of 112.

11 There is a useful Microsoft licensing brief on downgrade rights available here.

Thanks All


This website is a way to give back to the licensing community and as an information resource for all customers that work with Microsoft software and licensing. I hope you find it of value.

Tony Mackelworth is Head of Microsoft Advisory Services at SoftwareONE

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Document Author: Tony Mackelworth, Head of Microsoft Advisory Services, SoftwareONE Inc.