Licensing for Windows VMSS agents

Question

Licensing for Windows VMSS agents

Vallan Sherrod 0

Hi,

We are creating an agent pool from custom Azure VMs in order to build LabVIEW code. We had to make a custom VM since there are no Azure hosted ones that contain LabVIEW. We started with an Azure VM, added our needed customized software, deployed the VMSS, and created the agent pool successfully. However, I realized I needed to take care of the Windows licensing for this VMSS.

Our image was built from the generic VM running Windows 10 Pro on Azure. I am reading that or VMSS for build agents, the included licensing is only available for Windows Server. Is this true? How can I go about properly licensing the VMs in the scale set with Windows 10 Pro? Or do I need to recreate the scale set from scratch again on top of a Windows Server VM?

Best,

Vallan

1 answer

Your answer

Answer 1

Bodapati Harish 315 Microsoft External Staff

Hello @Vallan Sherrod ,

As per your questions, please find the information below. I hope it helps clarify your queries.

Is the included licensing for VMSS build agents only for Windows Server?

Yes, that's correct. Microsoft typically provides built-in licensing support such as Azure Hybrid Benefit for Windows Server VMs used in scale sets. However, Windows 10 Pro doesn't receive the same level of support in this context since it's generally intended for personal or desktop use, not server workloads.

For more details, you can refer:

How do I properly license VMs in a scale set running Windows 10 Pro?

To use Windows 10 Pro in your VMSS, you would need to go with a bring-your-own-license (BYOL) model. This means:

Purchasing valid Windows 10 Pro licenses yourself.
Making sure each instance is activated correctly.

This approach can be costly and hard to scale, especially if you're spinning up multiple instances. Azure does not offer a pay-as-you-go licensing model for Windows 10 Pro in VMSS, which makes this solution less than ideal for most use cases.

For more information, refer:

Should I recreate the VMSS using a Windows Server image?

Yes, that might be the simplest and most scalable path forward. Windows Server (e.g., 2019 or 2022) integrates smoothly with Azure's licensing model for scale sets. You can install LabVIEW and your other required tools on this base image, just as you did with Windows 10 Pro.

Checking with National Instruments to ensure that your version of LabVIEW is fully compatible with Windows Server (it usually is). This setup would allow you to avoid the licensing hurdles and streamline future scaling or maintenance.

Hope this helps!

If the answer is helpful, please click Accept Answer and kindly upvote it. If you have any further questions about this answer, please click Comment.

Bodapati Harish 315 Reputation points Microsoft External Staff

2025-04-10T03:57:52.5033333+00:00

Hello @Vallan Sherrod ,

Following up to see if you have chance to check the previous response and help us with requested information to check and assist you further on this.
Bodapati Harish 315 Reputation points Microsoft External Staff

2025-04-11T03:18:26.59+00:00

Hello @Vallan Sherrod ,

We haven’t heard from you on the last response and was just checking back to see could you please provide more details on your requirement so that I can assist you further.
Vallan Sherrod 0 Reputation points

2025-04-11T14:01:04.2833333+00:00

Hi @Bodapati Harish ,

Thanks for you answer and sorry for my delayed response. This is very helpful. We actually are a pretty small company at the moment and would at most have only 3 machines running at a time (but most likely just 1 or 2).

Loading the custom software onto the image actually takes quite a bit of time (even though you would think it wouldn't) so I would prefer to not have to create the image from scratch again if possible, but understand if I do need to.

With this in mind, if we have 2 or 3 licenses of Windows Pro that are reserved for these machines would that work? Or do we need to actively license them each time they come online? Obviously on a scale-set for build agents that would be less ideal. Some reading I was doing seemed to imply as long as you can say you have a license for it you are good. But not sure if that is true?
Bodapati Harish 315 Reputation points Microsoft External Staff

2025-04-14T07:50:48.3133333+00:00
Hello @Vallan Sherrod ,

Yes, technically, you can use your existing Windows 10 Pro licenses in a small-scale setup with VMSS, assuming you are following a bring-your-own-license (BYOL) approach. Since you're running only 1 to 3 instances at a time, this model might be acceptable under certain conditions. However, there are important limitations to consider.

To use Windows 10 Pro in Azure VMSS with BYOL, you must ensure:

You have valid Windows 10 Pro licenses assigned for each concurrently running instance.

Each VM instance is properly activated, either using a Multiple Activation Key (MAK) or through a Key Management Service (KMS) if you have a Volume Licensing Agreement.

You are able to maintain compliance with Microsoft’s licensing terms, which require licenses to be dedicated to individual users or devices.

That said, VMSS environments are dynamic by design—they create, destroy, and scale VM instances automatically. This nature makes Windows 10 Pro less suitable for scale sets because:

Windows 10 Pro is generally licensed for personal or end-user desktop use and is not intended for scalable or headless workload environments.

Azure does not offer built-in licensing support (like Azure Hybrid Benefit) for Windows 10 Pro in scale sets.

Activation challenges may occur whenever VM instances are re-imaged, replaced, or scaled, requiring manual intervention unless your licensing infrastructure is automated and robust.

Given these constraints, continuing with Windows 10 Pro in VMSS is not ideal for long-term scalability or automation. If possible, transitioning to a Windows Server-based image would be a more scalable and compliant path forward. Windows Server editions (such as 2019 or 2022) are fully supported in VMSS, and Azure provides streamlined licensing support through Azure Hybrid Benefit or pay-as-you-go options.

You can customize a Windows Server VM just as you did with your current image by installing LabVIEW and the other required tools. Before proceeding, please confirm with National Instruments that your version of LabVIEW is compatible with Windows Server—most recent versions are.

and finally,

You may continue using your existing Windows 10 Pro licenses if you are within compliance and running only a few instances.

However, for a more scalable and supportable approach, recreating the image on Windows Server is recommended.

Please let me know if you have any question, I'll happy to assist you.
Bodapati Harish 315 Reputation points Microsoft External Staff

2025-04-15T06:22:06.1133333+00:00

Hello @Vallan Sherrod ,

Following up to see if you have chance to check the previous response and help us with requested information to check and assist you further on this.
Bodapati Harish 315 Reputation points Microsoft External Staff

2025-04-16T05:07:13.41+00:00

Hello @Vallan Sherrod ,

We haven’t heard from you on the last response and was just checking back to see could you please provide more details on your requirement so that I can assist you further.

Share via

Licensing for Windows VMSS agents

1 answer

Your answer