We have a small Azure Virtual Desktop deployment for four concurrent users, using one Windows Server 2025 Datacenter session host. The environment is Entra-joined only, with no on-premises Active Directory Domain Services or other domain controller. The 120-day RDS grace period has expired, so we need to purchase the correct licenses.
The confusing part is that Per-User RDS CAL tracking appears to require user objects in AD DS, while workgroup-style deployments support Per-Device CALs instead. However, Per-Device CALs do not appear to receive the same Azure license-mobility treatment as User CALs. We also understand that purchased CAL types cannot simply be converted later.
The application involved is an ERP system installed on the server, so moving immediately to a Windows 11 Enterprise multi-session host is not currently considered practical. We are trying to find the cleanest, fully compliant way to run Windows Server 2025 with RDP access for four users without introducing unnecessary infrastructure.
Possible approaches include deploying Microsoft Entra Domain Services, adding a small domain controller and using RDS User Subscription Licenses through a CSP, or rebuilding the host with Windows 11 Enterprise multi-session. Is there another supported licensing or architectural option, or is a domain service and a different host design effectively required?
3 Answers
If the ERP must remain on Windows Server, adding a domain service may be the practical route. A small domain controller or Microsoft Entra Domain Services deployment can provide the directory and infrastructure needed for user-based RDS licensing and management. That adds cost and administration, but it is cleaner than trying to make an Entra-only, workgroup-style Server session host satisfy requirements it was not designed to meet.
The underlying ERP support requirement may be the real constraint here. Some vendors support the application on Windows Server but not on Windows 11 Enterprise multi-session in production, even if the application technically runs there. Confirm the vendor's supported operating systems first; if multi-session is excluded, the choices may effectively be adding directory infrastructure or moving the ERP to a separate supported server while using multi-session for user desktops.
The simplest architecture is usually to avoid Windows Server as the user session host. Windows 11 Enterprise multi-session is designed for pooled Azure Virtual Desktop sessions, supports multiple concurrent users, and works well with applications such as Microsoft 365 Apps. You can install the AVD agent, use FSLogix for profiles, and avoid the Windows Server RDS CAL issue. The ERP application's support matrix would need to be checked before making that change.
That support distinction is easy to overlook. An application working on a client OS is not necessarily vendor-supported there, especially in staging or production, so the licensing decision should follow the ERP vendor's documented requirements.