Licensing Guide
STACKIT offers customers two options for licensing their Windows Server. Customers can choose the variant that best suits his needs.
As part of our services, customers can either use predefined Windows Server Standard images provided by STACKIT in the STACKIT Cloud Portal, via the STACKIT API or use their own customized images to create Windows Servers.
STACKIT does not provide preconfigured “Bring Your Own License” images, but offers the customers the option to upload and use their own customized images via STACKIT IAAS API (see How to use custom Images with the IaaS-API).
However in this case customers are fully responsible for the proper licensing of the operating system and the installed software on the Windows Server.
STACKIT Windows Server Standard Images
Section titled “STACKIT Windows Server Standard Images”When customers start a Windows Server from a STACKIT provided Standard Image (i.e. Windows Server 2025 Standard), all required licenses to use the Windows Server as an operating system are included. Windows Server Client Access Licenses (CALs) are not required.
STACKIT does not provide Remote Desktop Service User Subscriber Access Licenses (SALs). Customers are responsible for properly licensing their Remote Desktop Service Users via their own eligible Microsoft agreements. They can bring their own licenses utilizing the Flexible Virtualization Benefit (FVB).
Customer provided Windows Server Images
Section titled “Customer provided Windows Server Images”When customers upload an own customized image to STACKIT and start a Windows Server from it, STACKIT does not provide any licenses for Windows Server as an operating system. Customers are fully responsible to have their environment properly licensed.
They must leverage the Flexible Virtualization Benefit (FVB) to Bring Your Own Licenses (BYOL) for the operating system and other installed Microsoft products. The details of the FVB and customer responsibilities are described in the section below: Flexible Virtualization Benefit (FVB) and Customer Responsibilities.
What is included (System Software/ Operating System)
Section titled “What is included (System Software/ Operating System)”If a customer uses a STACKIT Windows Server Standard Image (SPLA):
- Schwarz IT KG (“STACKIT”) provides the customer Microsoft Windows Servers licenses.
- If a customer uses a STACKIT Windows Server Standard Image the Service Offerings are licensed under the Microsoft Service Provider Licensing Agreement (SPLA) by STACKIT.
- The customer receives dedicated Virtual Machines which are hosted on shared physical Servers (Hybrid Hosting).
- Note: STACKIT does not provide or charge for Remote Desktop Service User Subscriber Access Licenses (SALs). Customers must BYOL for RDS access using the Flexible Virtualization Benefit (FVB).
Comparison of available Windows Server License Types: SPLA licensed vs. customer licensed process:
| Windows Server started from STACKIT Standard Image (licensed with SPLA) | Windows Server started from customer provided image (without license) | |
|---|---|---|
| OS Licensing | STACKIT is responsible for the customer’s operating system licenses. | Customers are responsible for their operating system licenses (BYOL via FVB). |
| Remote Desktop Service User Licenses | STACKIT does not provide RDS SALs. Customers must BYOL for RDS access via FVB. | Customers are responsible for properly licensing their Windows users with appropriate licenses (BYOL via FVB). |
| Environment | Shared environment. | Shared environment. |
| License Monitoring | STACKIT provides a scanning agent in the image, which scans the installed Microsoft products once a day. | Customers are responsible to monitor for installed Microsoft products. Scanning agent is not installed in the image. |
| Flexible Virtualization Benefit (FVB) Eligibility | Customers with eligible licenses (subscription or SA) must leverage the FVB for installing additional Microsoft products (other than the operating system). | Customers with eligible licenses (subscription or SA) must leverage the FVB for the operating system and all other used Microsoft products. |
Licensing Requirements
Section titled “Licensing Requirements”Responsibilities and Licensing
Section titled “Responsibilities and Licensing”- STACKIT is only responsible for the licensing of the Microsoft Windows Servers operating system under their Microsoft SPLA contract when STACKIT Windows Server Standard Images are used.
- Customers are responsible for the licensing of all applications that are installed on these Windows Servers according their own licensing contracts for all publishers.
- Customers are responsible for the licensing of the Microsoft Windows Server operating system if they bring their own customized image.
For the licensing of Microsoft products under own contracts, customers must use the Flexible Virtualization Benefit (FVB). This includes licensing for:
- The Windows Server operating system (if BYOL).
- Remote Desktop Services (RDS) access.
- Other installed Microsoft applications.
Microsoft Licensing Status for Key Products (BYOL via FVB)
Section titled “Microsoft Licensing Status for Key Products (BYOL via FVB)”The following table summarizes the licensing status for key Microsoft products that may, or may not be used in the STACKIT environment. This list is subject to change.
| Software Category | Restriction/Status | Customer Compliance Action Required |
|---|---|---|
| Server Licenses without Software Assurance (SA) | Not Eligible for FVB. | Must ensure all BYOL server licenses are subscription licenses or covered by active SA. |
| Desktop Applications (e.g., Office Desktop Apps, Microsoft 365 Apps) | Not Eligible for general BYOL. If used in VDI, access requires eligible subscription licenses via FVB. | Must use appropriate licensing and shared activation features (e.g., Microsoft 365 Apps) under FVB rules. |
| Windows Desktop OS (e.g., Windows 10/11) | Restricted in shared environments. Access requires highly specific subscription licenses (VDA, M365) via FVB. | Must ensure users have the required VDA/M365 subscription licenses for remote access. |
| Microsoft Server Applications (Exchange Server, SharePoint Server, System Center) | Allowed, but must be properly licensed by the customer (BYOL/FVB). | Must provide subscription licenses or SA-covered licenses. Customer is responsible for licensing the server software and all required Client Access Licenses (CALs) for users accessing the application. |
| SQL Server (All Editions) | Allowed, but must be properly licensed by the customer (BYOL/FVB). | Must provide subscription licenses or SA-covered licenses, following per-core minimums (e.g., a minimum of four licenses per VM for SQL Server Enterprise/Standard). |
| Developer Tools (e.g., Visual Studio, MSDN) | Allowed, but usage is strictly limited to non-production activities (development, testing, demonstration). | Must ensure usage is non-production only. |
Flexible Virtualization Benefit (FVB) and Customer Responsibilities
Section titled “Flexible Virtualization Benefit (FVB) and Customer Responsibilities”Overview of Flexible Virtualization Benefit (FVB)
Section titled “Overview of Flexible Virtualization Benefit (FVB)”The Flexible Virtualization Benefit (FVB) is an expansion of the outsourcing software management right for customers with subscription licenses or licenses with active Software Assurance (SA). This benefit expands your existing rights to deploy software on Authorized Outsourcers’ servers, which can be either dedicated to a single customer or shared.
- STACKIT qualifies as an Authorized Outsourcer.
- The FVB applies broadly to all Microsoft software products, including desktop applications, developer tools, and server applications. Crucially, it covers products like Windows Server and desktop products (such as Remote Desktop Service Client Access Licenses - CALs).
Follow this link for more information about Flexible Virtualization Benefit (FVB): Flexible Virtualization Benefit
Customer Responsibilities for Licensing (BYOL)
Section titled “Customer Responsibilities for Licensing (BYOL)”When deploying software on STACKIT’s shared servers under the FVB, customers are required to:
- Possess Eligible Licenses: You must have subscription licenses or licenses with active Software Assurance (SA).
- Ensure Compliance: The same terms that govern on-premises use also apply to your use of licenses deployed under the FVB. You, the customer, remain responsible for ensuring compliance with the terms and conditions of your agreements with Microsoft.
- Refer to Product Terms: You must refer to the Product Terms to determine when the FVB applies and how to exercise those rights: Microsoft Product Terms
Bringing Your Own Remote Desktop Service (RDS) Licenses
Section titled “Bringing Your Own Remote Desktop Service (RDS) Licenses”Customers must Bring Your Own License (BYOL) for Remote Desktop Services access.
- Eligible Licenses: You can use eligible licenses for Remote Desktop Services access under the FVB. These typically include RDS Client Access Licenses per User (CALs) with Software Assurance (SA). RDS per Device CALs are generally not eligible.
- Licensing Principle: The RDS CALs with SA are used under the FVB to access Windows Servers provided by STACKIT. The access must be licensed for a named user (a single person).
- Scope: You need to license the potential access, not only the effective access. You must technically ensure that no users can access the server who are not licensed for RDS.
- Reassignment: You may move eligible Windows Server licenses (including RDS CALs) between servers within STACKIT whenever needed. If moving licenses to a different outsourcer or server farm, you must wait 90 days before making the change.
Installed Additional Software and Audit Risk (Non-Compliant Software)
Section titled “Installed Additional Software and Audit Risk (Non-Compliant Software)”Customers can use the FVB to install and license additional Microsoft software on their Virtual Machines using their own eligible licenses.
- Customer Responsibility: Customers are fully responsible for the management and licensing of all other software on the VMs, including installation, operation, maintenance, and support. Customers should refer to the product terms and terms of services regarding their contractual obligations with STACKIT and Microsoft.
- STACKIT’s Right to Act: If Microsoft reasonably believes that a customer is not complying with the End User Agreements and unlicensed software is used, STACKIT is contractually bound to cooperate in good faith with Microsoft to investigate and remedy the non-compliance. STACKIT has the right to extraordinarily terminate the customer’s affected Windows Servers in case of non-compliance.
- Audit Note on Monitoring: Microsoft auditors may require the inspection of all servers that contain licensed products, especially in a shared environment. Customers are responsible for monitoring for installed Microsoft products on BYOL servers, as the STACKIT scanning agent is not installed on customer-licensed images. For Windows Servers based on a Standard image licensed and provided by STACKIT, the STACKIT scanning agent is installed to scan installed Microsoft products once a day. The Customer must ensure this agent is not uninstalled, deactivated, changed, or removed. If STACKIT or an independent auditor conducts an audit, the customer must provide all relevant information and grant access to all Windows Servers where the licensed products are used.