Re: [HTCondor-users] Doubt regarding job priorities on distributed scheduling

[Todd L Miller <tlmiller@xxxxxxxxxxx>]

> I have read that job priorities are constrained per scheduler, So If I have
> distributed scheduling how can I ensure that the job priorities are still
> obeyed at user level? i.e. Is there any way to control the queue that the
> negotiator maintains (or) any way to convey the negotiator to pick jobs
> from the Scheduler which has higher priority jobs with any macro?

	The negotiation algorithm is described in the manual:

https://htcondor.readthedocs.io/en/latest/users-manual/managing-a-job.html#changing-the-priority-of-jobs

If I understand the algorithm correctly:

	The negotiator _always_ goes in user (accounting principal) 
priority order.  Let's assume that you submitted as the same user (and 
authenticated the same way) on both schedds, and that there are no other 
users with jobs in the queue on either schedd, just for simplicity.

	Given a user with jobs in more than one queue, the negotiator 
_always_ completes negotiation for that user's job in a single schedd 
before moving on to the next.  So you definitely can't have a queue with 
priority 10 and 30 jobs and another queue with priority 20 and 40 jobs and 
expect them to be scheduled in priority order (any resources left over 
after the higher-priority jobs are scheduled on schedd A will go to 
scheduling lower-priority jobs on schedd A).

	_Which_ schedd gets contacted first is currently not specified, 
which I suspect means hashtable order.  AFAICT, HTCondor doesn't currently 
support specifying this order, so you're out of luck with respect to 
simple solutions.

	If you want to get _really_ exotic, however, you could try playing 
games with NEGOTIATOR_JOB_CONSTRAINT and running multiple negotiators, 
which each negotiator looks at a different subset of user job priorities.

- ToddM