CC Hameed continues his awesome posts on the new presentation virtualization technologies in the Windows 2008 R2 and Windows 7 suite.
Today we’re continuing on with Remote Desktop Services, with a look at Remote Desktop Services Virtualization (or RDS-V, for short). You may also hear RDS-V referred to as Virtual Desktop Infrastructure (VDI). RDS-V provides remote desktop access to managed desktop environments hosted in Hyper-V on Windows Server 2008 R2. OK, there are way too many technical buzzwords in that last sentence, aren’t there? Simply put, in the same way that RemoteApp makes applications available to users through individual Remote Desktop Services sessions, RDS-V provides access to specific virtual machines (desktops) through a similar mechanism. So, what does it really do?
RDS-V uses the Remote Desktop Connection Broker to determine where the user is redirected. If a user is assigned and requests a personal virtual desktop, RD Connection Broker redirects the user to this virtual machine. If the VM is not turned on, RD Virtualization turns on the VM and then connects the user. If the user is connecting to a shared virtual pool, then the RD Connection Broker checks to see if the user already has a connected session in the pool. If the user has a disconnected session then they are reconnected to that VM. If the user does not have a disconnected session, a VM in the pool is dynamically assigned to the user – if one is available. A quick note here, the Hyper-V server role has to be installed on the same system that has the RD Virtualization role service installed. Let’s take a quick look at the fairly simple high-level RDS-V topology:
The different components of RDS-V are as follows:
- Connection Broker – given an authenticated user and their associated request for an application or desktop, the Broker determines which RDS Server or VM image can best satisfy the request
- Redirector – RD Session Host Server whose purpose is to query the Broker on the RDS Client’s behalf. After querying the Connection Broker, the Redirector sends an RDP redirection packet back to the RDS Client
- RDS Assignment Database – representation of the AD Schema extensions that provide end-user mappings to a particular VM Host image
- Web Portal – web page that shows the user all the applications / desktops they can access
- VM Host – Machine on which the VM images are hosted. The VM Host Agent service runs on this machine. The service is controlled by the Connection Broker and can perform certain actions such as spinning up a VM image