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Creating an ESU license (Purchasing ESUs)

Slightly bizarrely, to purchase Azure Arc ESUs you need to create an ESU license in the Azure Management Portal. That license can then be activated, which is when billing starts, or it can remain deactivated until you’re ready to use it. When it is activated, it can then be assigned to a server, which is when the ESUs are automatically delivered to the server.

So, what is an ESU license? It’s like a custom order for ESUs where you choose whether the ESUs should be applied to physical or virtual cores, using Standard or Datacenter edition. It’s worth going through some of the steps for creating an ESU license as there are several noteworthy points from a licensing perspective. You can find the technical documentation for this process here.

The first step of creating an ESU license is to choose an Azure Subscription. This is important from a billing perspective since the ESUs will be billed against whatever payment mechanism that Azure Subscription is linked to – an EA, an MCA-E, or through a CSP partner. Usually, an Azure Subscription is a good way of separating out budgets – so if you purchase something in your Azure Subscription it can’t be used by a resource in another Azure Subscription. However, that doesn’t apply to ESUs and ESU licenses can be linked to servers in another Azure Subscription in the same tenant. You also choose a Resource Group at this stage and perhaps the only thing to note is that you can only create 800 ESU licenses in a single Resource Group.

The Instance details form is the next part of the process:

Here you need to supply the ESU license name. Obviously this is completely up to you, but it’s worth considering here how many licenses you’re going to create. Are you going to create an ESU license for each virtual machine that you have by choosing 8 Standard edition virtual cores? If so, you might want the ESU license to be tied to the virtual machine name in some way. Or, you could create a (made-up term) super ESU license for your 5 virtual machines by choosing 40 Standard edition virtual cores, since an ESU license may be assigned to more than one physical or virtual server. The choice is yours, but clearly appropriate naming can be helpful.

Then you need to choose whether you want to activate now or later, and as mentioned, the billing and ability to assign it to a server only starts when it is activated.

Next up we have the license details:

Here you choose the edition (SKU) – Standard or Datacenter, and the core type – physical or virtual. Note that if you choose virtual cores, the edition will automatically be changed to Standard and this is the rate that will be used, regardless of whether Standard or Datacenter edition is running in the virtual machine. This matches the way the licensing works with the Azure Hybrid Benefit – where you can assign Standard licenses to a Datacenter image running in Azure. And finally, you choose the number of cores, which must be a multiple of 2, and a minimum of 8 if you’ve chosen virtual cores, and a minimum of 16 if you’ve chosen physical cores. Note that this has changed from when ESUs first launched back in October 2023 where you were required to specify numbers of packs in 2 cores or 16 cores. Today, each ESU license can cover up to and including 10,000 cores.

And, finally, at the bottom you attest that your Windows Server workloads are covered by one of the qualifying license options: licenses with SA, or acquired as Software Subscriptions, or running on a SPLA partner’s servers.