Dispatch manager Scheduler 5.4

In order to decouple the scheduling process, GridWay uses a Scheduler module to schedule jobs.

The format to send a scheduling request to the Scheduler, through its standard input, is:

SCHEDULE - - -

On the other side, the format to receive a response from the Scheduler, through its standard output, is:

OPERATION JID RESULT INFO

Where:

• OPERATION: Is the operation requested to the Dispatch Manager. The Dispatch Manager only supports the SCHEDULE_JOB operation.
• JID: It is a job identifier.
• RESULT: It is the result of the operation. Could be SUCCESS or FAILURE.
• INFO: If RESULT is FAILURE, it contains the cause of failure. Otherwise, if OPERATION is SCHEDULE_JOB it contains a resource specification in the form HID:QNAME:RANK, where:
  • HID: It is the host identifier, as provided by gwhost command.
  • QNAME: It is the queue name.
  • RANK: It is the rank of the host.

GridWay 5 includes a scheduler template (“gw_scheduler_skel.c”) to develop custom schedulers. As an example a Round-Robin/Flooding scheduler can be found in the GridWay distribution (“gw_flood_scheduler.c”, in “$GW_LOCATION/src/sched/”). This is a very simple scheduling algorithm, which maximizes the number of jobs submitted to the Grid.