License resources work exactly like global resources with the added advantage that they can be dynamically updated in the Supervisor by an external application.
Normally, as jobs are dispatched and executed, the Supervisor continually updates the global resource counts to match. However, many sites subscribe to a single floating license server to control all licensed applications, not just the ones running on a compute farm. If those licenses are allocated to other processes not monitored by Qube, the Supervisor runs the risk of dispatching a job where there are no licenses available for the application it will try to execute.
By using an external application to monitor the state of the license server, the Supervisor can be updated on a regular basis to ensure the Supervisor is fully aware of the actual number of licenses available.
Configuring the system requires two separate components:
- The Supervisor must be configured with a license resource equal to the maximum license allocation to the compute farm.
- An external application must be developed that can monitor the license server and call qbupdateresource to update the Supervisor on a regular basis.
In this case, only the Supervisor needs to be configured with a license resource specification:
supervisor_global_resources= resspec [, resspec…]
The resspec uses the keyword license:
license.name=quantity
It is beyond the scope of this document to describe how to write a script that can poll a license server. At some point, however qbupdateresource should be called:
qbupdateresource -name license.name -total license_total -used license_used
where name is the name of the license resource in the Supervisor, license_total is the total number of application licenses managed by the license server, and license_used is the number in use at the time.
Example
Here is an example of the license resource configuration of five mental ray licenses:
supervisor_global_resources = license.mentalray=5
and an example call to qbupdateresource that a total 5 licenses are installed, and 2 are currently in use:
% qbupdateresource –name license.mentalray -total 5 -used 2