We present a new architecture for the integration of distributed resource management systems and parallel run-time environments such as MPI. The architecture solves the long-standing problem of achieving a tight integration between the two in a clean and robust manner that fully enables the functionality of both systems, including resource limit enforcement and accounting. We also present a more uniform command interface to the user, which simplifies the task of running parallel jobs and tools under a resource manager. The architecture is extensible and allows new systems to be incorporated. We describe the properties that a resource management system must have to work in this architecture, and find that these are ubiquitous in the resource management world. Using the Sun™ Cluster Runtime Environment, we show the generality of the approach by implementing tight integrations with PBS, LSF and Sun Grid Engine software, and we demonstrate the advantages of a tight integration. No modifications or enhancements to these resource management systems were required, which is in marked contrast to ad-hoc approaches which typically require such changes.