An Insight into the Architecture of Condor - A Distributed Scheduler

This article gives a detailed description of the Condor system-a distributed scheduler. A typical Condor system consists of four components: A Condor pool, the central manager, submitting machine and execution machine. The ClassAd is a flexible representation of the characteristics and constraints of both machines and jobs in the Condor system. Matchmaking is the mechanism by which Condor matches an idle job with an available machine. Condor plays the role of matchmaker by continuously reading all job ClassAds and all machine ClassAds, matching and ranking job ads with machine ads. Condor ensures that the requirements in both ClassAds are satisfied. The architecture of Condor depends on the interaction of the following Condor daemons: condor_master, condor_collector, condor_negotiator, condor_schedd, condor_shadow, condor_startd, and condor_starter. By integrating the basic Condor commands into a GUI-based program, Condor becomes more user-friendly and more convenient to use.