Hello,
Managing RDS CALs is complex because this not a matter of finding a list of installations on servers that would show: "this device is performing remote connection to a Citrix server".
As well, the CAL evidences (Client Access Logging) are not reliable for determining the need for RDS CALs... the CAL inventory for Windows Server will show you the list of computers that did RDP sessions... but these sessions may not require a license, for instance if this was in the context of 2 or 1 concurrent remote sessions.
The only reliable approach is to use a PowerShell script, that reads from AD the list of Citrix license servers, then queries each of the servers and runs the "RDS License Consumption Report" for each of then and gathers the data in a CSV file.
A second step can read the CSV file (simple approach) and allocate users or devices directly to licenses... and second more sophisticated steps is to read the data from the CSV file, put in a local SQL database, run allocations calculation and optimization script and perform two sets of allocations, to the RDS licenses... and to the RDS Optimal licenses (an optimization logic is applied to remove double consumptions (users and devices CALs, or multiple versions CALs).
The attached documentation is very draft, but contains the code already used in a project... It should be used by someone who has good knowledge and understanding of FNMS db schema and SQL language.
