Leaf queues maintain a list of runnable and non-runnable apps. FairScheduler marks an app non-runnable for different reasons: exceeding the following properties of the leaf queue:
(1) queue max apps,
(2) user max apps,
(3) queue maxResources,
It would be nice to log the reason an app isn't runnable. The first three are easy to infer, but the last one (maxAMShare) is particularly hard. We are going to log all of them and show the reason if any in WebUI application view.