Qube is an even-driven queuing system. Because of this, Qube inherently tracks common job events. These include events such as when a job starts running, or when a host reports new resources available.
The advantage of an event-driven system is that the queuing algorithm and the jobs themselves can take action based on those events.
For a complete explanation on how Qube allows jobs to modify the logic surrounding the job, please reference the Callbacks section of the documentation.