1. A method of operating a scheduler within a computing cluster to schedule a plurality of jobs for concurrent execution on resources of the computing cluster, the method comprising: with at least one processor: receiving for each of a plurality of jobs, a request for a minimum number of computing resources; computing for each of the plurality of jobs a respective desired allocation of the resources; adjusting resources among the plurality of jobs by: identifying a first job of the plurality of jobs using less than the respective desired allocation of resources; identifying a second job of the plurality of jobs using more than the respective desired allocation of resources; de-allocating a resource from the second job and allocating the de-allocated resource to the first job.