Three daemons provide the functionality of the grid engine system.
The center of the cluster's management and scheduling activities, sge_qmaster maintains tables about hosts, queues, jobs, system load, and user permissions. sge_qmaster receives scheduling decisions from sge_schedd and requests actions from sge_execd on the appropriate execution hosts.
The scheduling daemon maintains an up-to-date view of the cluster's status with the help of sge_qmaster. The scheduling daemon makes the following scheduling decisions:
Which jobs are dispatched to which queues
How to reorder and reprioritize jobs to maintain share, priority, or deadline
The daemon then forwards these decisions to sge_qmaster, which initiates the required actions.
The execution daemon is responsible for the queue instances on its host and for the running of jobs in these queue instances. Periodically the execution daemon forwards to sge_qmaster information such as job status or load on its host.