The cost model for Azure Stack HCI

Technologies from different vendors are available on the market that allow you to build hyper-converged infrastructures (HCI). Microsoft in this sector offers an innovative solution called Azure Stack HCI, deployed as an Azure service, that allows you to achieve high performance, the latest security features and native integration with Azure services. This article describes how much you need to invest to get the Azure Stack HCI solution and what aspects you can consider to structure the cost model as you like..

Premise: OPEX vs CAPEX

The term CAPEX (contraction from CAPital EXpenditure, ie capital expenditures) indicates the cost of developing or providing durable assets for a product or system.

Its counterpart, operational expenditure or OPEX (from the English term OPerational EXpenditure) is the cost of managing a product, a solution or a system. These are also called costs O&M (Operation and Maintenance) or operating and management costs.

CAPEX costs usually require a budget and a spending plan. Also for these reasons, companies generally prefer to incur OPEX costs, as they are easier to plan and manage.

Clarify these concepts, now let's see the Azure Stack HCI cost model and how to get a totally OPEX model.

Hardware costs

In order to activate the Azure Stack HCI solution, it is necessary to have on-premise hardware to run the dedicated operating system of the solution and to run the various workloads. There are two possibilities:

  • Azure Stack HCI Integrated Systems: determined by the vendor, offer specially structured and integrated systems for this solution, that provide an appliance-like experience. These solutions also include integrated support, jointly between the vendor and Microsoft.
  • Azure Stack HCI validated nodes: implementation takes place using hardware specifically tested and validated by a vendor. In this way you can customize the hardware solution according to your needs, going to configure the processor, memory, storage and features of network adapters, but respecting the supplier's compatibility matrices. There are several hardware vendors that offer suitable solutions to run Azure Stack HCIand can be consulted by accessing this link. Most implementations are done in this way.

Figure 1 - Hardware deployment scenarios

Also for the hardware it is possible to make some evaluations to adopt a cost model based on rental. In fact,, major vendors such as HPE, Dell and Lenovo, are able to offer the necessary hardware in "infrastructure as-a-service" mode, through a payment model based on use.

Azure costs

Despite being running on premise, Azure Stack HCI provides for billing based on Azure subscription, just like any other service in Microsoft's public cloud.

Azure Stack HCI offers a free trial period that allows you to evaluate the solution in detail. The duration of this period is equal to 60 days and starts from when you complete the registration of the cluster environment in Azure.

At the end of the trial period, the model is simple and costs “10 € / physical core / month"*. The cost is therefore given by the total of physical cores present in the processors of the Azure Stack HCI cluster. This model does not provide for a minimum or a maximum on the number of physical cores licensed, much less limits on the activation duration.

Costs for Windows Server machines

The Azure costs listed in the previous paragraph do not include the operating system costs for guest machines running in the Azure Stack HCI environment. This aspect is also common to other HCI platforms, like Nutanix and VMware vSAN. There are two options for licensing Windows Server guest machines in Azure Stack HCI:

  • Buy Windows Server licenses (CAPEX mode), Standard or Datacenter, which include the right to activate the OS of guest virtual machines. The Standard Edition may be suitable if the number of Windows Server guest machines is limited, while if there are several Windows Server guest systems, it is advisable to evaluate the Datacenter Edition which gives the right to activate an unlimited number of virtualized Windows Server systems.
  • Pay for the Windows Server license for guest systems through your Azure subscription, just like in Azure environment. Choosing this option will incur a cost (OPEX) equal to "22.2 € / physical core / month ”* to be able to activate an unlimited number of Windows Server guest systems in the Azure Stack HCI environment.

*Costs estimated for the West Europe region and subject to change. For more details on the costs of Azure Stack HCI you can consult the Microsoft's official page.

Charges for other workloads running on Azure Stack HCI

The result we intend to pursue with the Azure Stack HCI infrastructure is to be able to run in an on-premises environment, not just virtual machines, but the same Microsoft public cloud workloads. To achieve this Microsoft is bringing the most popular Azure workloads to Azure Stack HCI and the following cost considerations apply to each of them:

  • Azure Kubernetes Service: the configuration of the K8s Arc enabled cluster is free **.
  • Azure Arc-enabled data services:
    • For SQL Server, customers can purchase SQL Server licenses in CAPEX mode or, who already has SQL licenses, can use Azure Hybrid Benefit for Azure Arc-enabled SQL Managed Instance, without having to pay the SQL license again.
    • If you want to switch to an OPEX model, you can obtain Microsoft SQL Server licenses through Microsoft's Azure Arc-enabled data services **.
  • Azure Virtual Desktop:
    • User access rights for Azure Virtual Desktop. The same licenses that grant access to Azure virtual desktops in the cloud also apply to Azure Virtual Desktop in Azure Stack HCI.
    • Azure Virtual Desktop Hybrid Service Fee. This fee is charged for each virtual CPU (vCPU) used by Azure Virtual Desktop session hosts running in Azure Stack HCI environment.

**For more details on Azure Arc costs you can consult this page.

Support costs

Azure Stack HCI, being in effect an Azure solution, is covered by Azure support with the following features:

  • A choice is provided between several Azure support plans, depending on your needs. Basic support is free, but in certain scenarios it is recommended that you at least consider Standard support, which provides a fixed monthly cost.
  • Support is provided by a team of experts dedicated to supporting the Azure Stack HCI solution.
  • You can easily request technical support directly from the Azure portal.


Azure Stack HCI allows you to bring cloud innovation into your datacenter and at the same time create a bridge to Azure. In the era of hybrid datacenters, a solution like Azure Stack HCI, allows you to structure the cost model as you wish and to have maximum flexibility. There are several vendors on the market offering solutions to build hyper-converged infrastructures (HCI) hybrid, and Azure Stack HCI can be very competitive, not only from the point of view of functionality, but also from the point of view of costs.

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