[Mauiusers] confused about standing reservations

Stephen Jones sjones at hep.ph.liv.ac.uk
Thu Feb 4 03:21:08 MST 2010


We use SRs to set-aside test nodes. The QOS etc makes the relationship 
fixed at both ends,
i.e. that-node can only be used by that-user, and that-user can only use 
that-node.

I'd say this about it. Maui seems to read the definitions once, at boot 
time. Subsequent
definitions in the maui.cfg file can conflict/interfere (so you have to 
check the whole file) and
subsequent command line reservations (via setres) can also 
conflict/interfere/override.
I'm not sure of the "order of priority", so to speak.

I'm certain that the assignment of jobs to nodes is done dynamically, 
not at job submission time.
The latter strategy would have bad consequences wrt maximizing the usage 
of nodes that become
free at (more or less) random times, i.e. at submission time, it is not 
possible to predict what the state
of the cluster will eventually be when the queued job is selected to be 
run.

Steve

SRCFG[ABCTESTRES] HOSTLIST=SOME_NODE
SRCFG[ABCTESTRES] USERLIST=SOMEUSER
SRCFG[ABCTESTRES] PERIOD=INFINITY
QOSCFG[ABCTESTRESonly] QFLAGS=USERESERVED:ABCTESTRES
USERCFG[SOMEUSER] QDEF=ABCTESTRESonly

Steve Johnson wrote:
> I've used SR's with decent success for blocking out access during lab times.
>
> Example:
> SRCFG[bloc122mw] GROUPLIST=root
> SRCFG[bloc122mw] STARTTIME=07:30:00
> SRCFG[bloc122mw] ENDTIME=17:00:00
> SRCFG[bloc122mw] DAYS=MON,WED
> SRCFG[bloc122mw] HOSTLIST=bloc122-[00-32]
>
> I also do pbsnodes -o via cron to mark the nodes offline so that Globus MDS
> reports the correct number of available nodes.  It also provides a second
> layer of protection against a job starting when it's not suppose to.
>
> It's a different story when using SR's in place of partitions.  I just
> couldn't get it to behave as desired in terms of keeping jobs from particular
> classes separated, so I went back to partitions.
>
> // Steve
>
>
> Tom Rudwick wrote:
>   
>> I recommend not using standing reservations. We found them to be buggy and
>> unreliable. I recommend using cron jobs to create regular reservations.
>>
>> Tom
>>
>>
>> skip at pobox.com wrote:
>>     
>>> I'm trying to use standing reservations (Maui 3.2.6p21) to avoid running
>>> jobs on certain nodes during work hours.  For example:
>>>
>>>     SRSTARTTIME[userver171]     07:00:00
>>>     SRENDTIME[userver171]       16:00:00
>>>     SRPERIOD[userver171]        DAY
>>>     SRDAYS[userver171]          MON TUE WED THU FRI
>>>     SRHOSTLIST[userver171]      userver171
>>>     SROWNER[userver171]         USER:kim
>>>     SRMAXTIME[userver171]       5:00:00
>>>
>>> I interpreted the above to mean that on weekdays jobs can only be run on
>>> userver171 by Kim between 07:00 and 16:00.
>>>
>>> This doesn't seem to work.  Jobs continue to be placed on that machine
>>> during the reserved period.
>>>
>>> Is the assignment of jobs to nodes done dynamically or at the time of job
>>> submission? 
>>>
>>> Thanks,
>>>
>>>   
>>>       
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>>     
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-- 
Steve Jones                             
System Administrator                    
High Energy Physics Division            
Oliver Lodge Laboratory                 
University of Liverpool                 http://www.liv.ac.uk/physics/hep/





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