Re: [Condor-users] about multiple scheduler issues

["Carson Hung" <carson@xxxxxxxxxxxxxx>]

Hi Dan,

Thanks a lot for your site (you are the author of that site :)

very clear explanation of the working of matchmaking process in condor-g
and how it works in USCMS.

I think what Erik's mean in replacing claiming of resources in condor-g is
by setting the CurMatches and WantAdRevaluate, right?

However, I am not very understand why Dagman is necessary in this case?

and in Dagman, all the jobs that is needed to be executed will be
pre-grouped into certain size and managed into a Dag file. In this case,
all the member of jobs in the same group can only be submited to the same
site, right? and the decision will be done in the negotiator site, but not
the matchmaker site, right? is there any method that I can change the
scheduling based on the conditions of grid sites in matchmaker site?

Thanks very much for your help.
Carson

>
> http://www.cs.wisc.edu/condor/USCMS_matchmaking.html
>
> Carson Hung wrote:
>
>>Hi Erik,
>>
>>One more question to ask, where can I find the USCMS writeup :)
>>
>>Thanks,
>>Carson
>>
>>
>>
>>>Hi Erik,
>>>
>>>Thanks very much for your clear explanation.
>>>
>>>You are right, I am actually asking if it is possible to have more
>>> than one negotiators with multiple schedulers. Since I think that case
>>> is possible to exist in condor-g environment.
>>>
>>>and I think you have answered my questions. Really thanks a lot.
>>>
>>>Thanks,
>>>Carson
>>>
>>>
>>>I have more understanding about the condor and condor-g
>>>
>>>
>>>
>>>>On Sat, Feb 19, 2005 at 04:40:24PM +0800, Carson Hung wrote:
>>>>
>>>>
>>>>>Hi,
>>>>>
>>>>>Since it is possible to have more than one schedulers/submittors in
>>>>> the clusters.
>>>>>So I would like to know if it is possible that 2 or more schedulers
>>>>> match the same resource to the different jobs if they come from
>>>>> different schedulers/submittors.
>>>>>
>>>>>
>>>>>
>>>>I think you really mean "if it is possible that 2 or more negotiators
>>>> match the same resources to different jobs if they come from
>>>> different schedds" - you can't use the term 'scheduler' twice :)
>>>>
>>>>In Condor, it's not really possible for the negotiator to match a
>>>> resource twice, because:
>>>>
>>>>A. There's only one negotiator, so it will only match a resource once
>>>> per neogotiaition cycle.
>>>>
>>>>B. It is possible for a resource to be matched twice - if it gets
>>>> matched in one negotiation cycle, but doesn't update the collector
>>>> before the next  negotiation cycle starts. We prevent this from
>>>> happening in two ways:
>>>>   1. The negotiation CANNOT start until at least 20 seconds have
>>>>passed
>>>>since the last one. That usually is good enough.
>>>>   2. The startd can detect if it's been matched twice, and can
>>>>recover,
>>>>if the 20 seconds wasn't good enough.
>>>>
>>>>In Condor-G, because there is no claiming (ie the resource doesn't
>>>> automatically tell the collector that it is no longer able to be
>>>> matched), matching twice is more of a problem. We ususally build-in
>>>> some sort of  claiming when we've deployed matchmaking in the past
>>>> (see the USCMS writeup I pointed you at eariler).
>>>>
>>>>If you advertise your resource to more than one collector/negotiator,
>>>> then matching twice is a real problem. In regular condor, it's not
>>>> possible for a startd to report to two different collectors, so it's
>>>> not a problem.
>>>>
>>>>-Erik
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>>>>
>>>>
>>>
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>>
>>
>>
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