hostname 0-n (was Re: [jsdl-wg] Issues for todays phone conference)

[Andreas Savva]

I have a followup question on changing the hostname from 0-1 to 0-n. In 
the spec we had said that hostname may refer to a single host or any 
logical group of hosts. (And that logical group could be anything 
understood by the system.)  The intention was to be able to do something 
like
<Resource>
  <HostName> the-nine-muses </HostName>
    ...
  <ResourceCount> <exact>2.0<exact></ResourceCount>
</Resource>

And get back, for example, resources "thalia" and "urania".

Doesn't this cover already (most of) the use case mentioned below and is 
there really a need to change the multiplicity of this element.

Andreas

Andreas Savva wrote:

>
> Karl Czajkowski wrote:
>
>> On Apr 12, Michel Drescher loaded a tape reading:
>> ...
>>  
>>
>>> 10) When/why did HostName change from 0-1 to 0-n? (reverted)
>>>
>>>   
>>
>>
>> At GGF-13 and who keeps trying to set it back to 1? :-)
>>  
>>
>
> Guilty as charged. It must have been in the last session that I missed.
>
> I am working on  releasing the next version of the spec. and it is 
> inconsistent in the definition of this element (some places * and some 
> ?). It was not clear which way was intended or why, hence the comment.
>
>> It is 0-n to allow for resource selection of nodes in a parallel
>> job. Chris Smith has that use case with LSF and I can endorse it as a
>> useful thing for parallel jobs too (whether it is in GRAM today or
>> not!).  This goes hand-in-hand with the notion of there being a count
>> for the resource element, meaning multiple resources must be allocated
>> to match the same element.  The semantics is each resource MUST have
>> one of the names in the list. In other words, if there are more
>> hostnames listed than resources requested, not all names are utilized,
>> or the match predicate for a host is membership of that host's name in
>> the list.
>>
>>
>>  
>>
> Thanks for the explanation, Karl. I'll have to think about it tomorrow 
> after I get some sleep. (Everything looks better in sunlight. :-)
>
> Andreas
>