The master host is central to the overall cluster activity. The master host runs the master daemon sge_qmaster and the scheduler daemon sge_schedd. Both daemons control all grid engine system components, such as queues and jobs. The daemons maintain tables about the status of the components, about user access permissions, and the like.
By default, the master host is also an administration host and a submit host. See the sections that describe those hosts.
Execution hosts are systems that have permission to execute jobs. Therefore execution hosts have queue instances attached to them. Execution hosts run the execution daemon sge_execd.
Administration hosts are hosts that have permission to carry out any kind of administrative activity for the grid engine system.
Submit hosts allow users to submit and control batch jobs only. In particular, a user who is logged in to a submit host can submit jobs with the qsub command, can monitor the job status with the qstat command, and can use the grid engine system OSF/1 Motif graphical user interface QMON, which is described in QMON, the Grid Engine System's Graphical User Interface.
A system can act as more than one type of host.