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You could also configure a queue condition to require one of three available licences for a particular application. To set this up, you would first create a Server Shared Resource called something like "License.XApp", for example. Next, the create a queue condition of type "Shared resource lock" and add the identifier: "License.XApp", select Read Lock . Select "Read" lock and enter 1 for the number of locks requriedrequired (as seen in the screenshot below). With this condition, once three builds are running and have acquired a lock on this resource, subsequent build will sit on the queue until one build finishes and releases a shared resource lock.
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