[HTCondor-users] Troubleshooting job eviction by machine RANK

[Graham Allan <allan@xxxxxxxxxxxxxxx>]

We've been running htcondor here for many years but with a fairly static 
configuration, in which jobs have only run on the machines owned by the 
research group.

We did this simply by defining a variable "CondorGroup" which is both 
defined per group, and used in the START expression, something like:

> CondorGroup = "novafarm"
> SUBMIT_EXPRS = CondorGroup, $(SUBMIT_EXPRS)
> START = (CondorGroup =?= "novafarm") || (CondorGroup =?= "system")

We're now trying (belatedly!) to enable opportunistic scheduling so that 
unused resources can be used more efficiently.
I am trying to do this by setting machine ranks, and then letting jobs 
run on available other-group systems by defining a variable "CanEvict" - so:

> CondorGroup = "novafarm"
> SUBMIT_EXPRS = CondorGroup, $(SUBMIT_EXPRS)
> START = (CondorGroup =?= "novafarm") || (CondorGroup =?= "system") || CanEvict
> RANK = (20 * CondorGroup =?= "novafarm") + (10 * CondorGroup =?= "bes3farm")
> MachineMaxVacateTime = 300

So then someone can submit a job with (eg) +CondorGroup = "general" and 
+CanEvict = True in order to run on any vacant slot.

What we find is that these jobs do start on the other-group machines, 
but when another group then submits their own jobs, the guest jobs never 
get evicted.

I don't have anything else defined regarding preemption:

> WANT_SUSPEND           = TRUE
> WANT_VACATE            = TRUE
> SUSPEND                = FALSE
> CONTINUE               = TRUE
> PREEMPT                = FALSE
> KILL                   = FALSE
> PREEMPTION_REQUIREMENTS        = FALSE
> PREEMPTION_RANK                = 0

but my interpretation was that RANK by itself should achieve the desired 
effect.

Have I written enough for anyone to say where I'm going wrong?

Thanks, Graham
--