Re: [Condor-users] Preemption completely off

[Matt Hope <matthew.hope@xxxxxxxxx>]

On 9/5/05, Andrew Stubbings <ajs@xxxxxxxxxxxxxxxxx> wrote:
> Can I confirm that the following will turn preemption completely off?
> 
> PREEMPT = False
> PREEMPTION_REQUIREMENTS = False

No it won't - you would also need to ensure that the machine (startd)
specified rank never evaluated to a different value for jobs which
were allowed to run on the machine. This is the default bahaviour
though.

> Why the need to specify both? One for the starter and one for the
> negotiator.
> Isn't there a way to avoid confusion and turn preemption off with just
> *one* expression?

Then what happens when *that* expression conflicts with the others...

Condor is a distributed system in many ways and this includes execute
nodes being 'smart'. They take responsibility for their own behaviour
in many situations (this is by design - if you supply your own
machines to a pool you may well want to place your own rules on their
usage).

PREEMPT is specifically for the local execute machine and so the
expression can reference the state of the local machine as well as the
local running job.

PREEMPTION_REQUIREMENTS is executed on the negotiator and therefore
has access to both the current and potential jobs in question.

There is no easy (and certainly no efficient) way to merge these two operations.

If you control the entire pool it is not too hard to set them both and
this is why the entry on disabling preemption exists in the manual
(note to condor team I would suggest a link to preempt and
preemption_requirements in this section)

http://www.cs.wisc.edu/condor/manual/v6.7/3_6Startd_Policy.html#SECTION00469500000000000000

Matt