Desktop virtualization

In a Virtualized Desktop Infrastructure (VDI) solution, the computer desktop environment is separated from the physical computer. Virtualized desktops are stored on a centralized or remote server and are provided to the users on the network. The users can access their work desktops from any location and any device.

The following desktop virtualization solutions are supported by Snow License Manager and SAM Core on Snow Atlas:

• Citrix VDI-in-a-Box

• Citrix Virtual Desktops

• Microsoft Virtual Desktop Infrastructure

• VMware Horizon View

The information in this chapter applies only to licensing the Windows desktop operating system for virtualization scenarios.

The challenge

Desktop virtualization provides advantages from an operational point of view, but it also adds complexity when it comes to licensing of the VDI environment.

Every device that connects to a Windows VDI will require Windows Virtual Desktop Access (VDA) rights. Windows VDA rights are available in the following scenarios:

• The accessing device is licensed with a qualifying operating system license and is also covered by Software Assurance (SA) for Windows

• The accessing device does not have a qualifying operating system, for example, thin clients, and cannot be licensed with Software Assurance, and is licensed with a separate Windows VDA subscription license.

The challenge is to obtain correct information on the actual number of VDA licenses that are required in a VDI environment in order to be compliant and avoid overspending:

• The server and management infrastructure of the VDI solution requires licensing.

• The operating systems of the virtual desktops require no licensing.

• The devices accessing the virtual desktops require licensing.

note

Actual licensing requirements may vary. Consult the reseller for advice.

Prerequisites

• Snow License Manager 8.0 or later, or SAM Core on Snow Atlas

• Snow Inventory Agent for Windows 5.0 or later, must be installed on all virtual desktops.

• Information on host/guest relationships (see preceding chapter)

Solution

Installation and preparation

To utilize the functionality for VDI and Windows VDA license requirement calculations in Snow License Manager or SAM Core, the Snow Inventory Agent for Windows is required to be installed on all virtual desktops.

When Snow Inventory Agent for Windows is used in a VDI solution there are some configuration settings that need to be applied to ensure accurate capture of all activities on each virtual desktop:

• The agent needs to be aware that it is part of a VDI.

• Each virtual desktop needs to get a unique client identifier.

• Information on all sessions and relevant application usage need to be captured before the virtual desktop session is shut down/re-provisioned.

For more detailed information on this configuration, see Snow Inventory Agent for Windows.

Calculation of license requirement

With Snow Inventory Agent for Windows installed on the virtual desktops, all devices that access them will be identified by Snow License Manager or SAM Core. A device may be, for example, a home PC, a smartphone, a thin client, or an inventoried computer.

In Snow License Manager or SAM Core, the fictional (and non-editable) application Windows Virtual Desktop Access is added to all of the identified devices. Calculation of license requirements for the Windows VDA is then performed according to the following conditions.

For a device that:

• Is an inventoried computer with a qualifying operating system license covered by Software Assurance for Windows - no Windows VDA license is required.

• Is an inventoried computer with a qualifying operating system license not covered by Software Assurance for Windows - a Windows VDA license is required.

• Is an inventoried computer without a qualifying operating system license - a Windows VDA license is required.

• Is not an inventoried computer - a Windows VDA license is required.

Device is inventoried	Device has OS license	License is covered by SA	Windows VDA license is required
Yes	Yes	Yes	No
Yes	Yes	No	Yes
Yes	No	-	Yes
No	-	-	Yes

In Snow License Manager and SAM Core, management of Windows VDA licensing is automated. However, to ensure correct license requirement calculations it is important that all purchases of Windows licenses with Software Assurance are registered with upgrade rights.

Presentation in the user interface

When the license requirement for a certain operating system is calculated, all virtual desktops that run the specific operating system are automatically excluded from the calculation.

In Snow License Manager and SAM Core, excluded virtual desktop operating systems are indicated by Virtual desktop infrastructure on the Compliance tab in Application details.

When the license requirement for Windows Virtual Desktop Access is calculated, devices that are covered by a Windows license with valid Software Assurance are automatically excluded from the calculation.

In Snow License Manager and SAM Core, excluded devices (with Software Assurance for Windows) are indicated by the comment Virtual desktop access on the Compliance tab in Application details.

Available reports

The following reports with VDI information are available in Snow License Manager and SAM Core:

• All devices that have accessed a VDI

  Presents all devices that have accesses a VDI, and the last logged on user of the device.

• All users that have accessed a VDI

  Presents all users that have access a VDI, and the last VDI that they accessed.

• Applications per VDI computer

  Presents all applications installed or used per VDI computer.