Hi all...
Thinking about the upcoming F2F meeting, we're going to need some
strawmen for people to poke fun at. Here's my first go (everything will
need XML serialization, of course):
CSG has one official operation:
GetCandidates(JobDefinition[] atomicJobs)
-> Candidate[]
Each Candidate is a structure containing:
EndpointReference eprOfBESToSubmitThisJobTo
JobDefinition configuredAtomicJob
ValuationTerm[] descriptionsOfQoSPriceEtc
We permit multiple jobs in the request because this is useful in a
setting where a CSG is defined hierarchically in terms of other CSGs
(a good way of building a wider Grid in my experience).
Any scheduling or reservation terms are done by writing extra things
into the JobDefinition elements. JSDL is flexible enough for this.
EPS needs at least this operation:
PlanExecution(JobDefinition atomicJob, SelectionPolicy selector)
-> ExecutionPlan
I don't know what the SelectionPolicy will look like, but basing it
off of Condor ClassAd selection rules might be a good start.
The ExecutionPlan is a structure containing at least:
EndpointReference eprOfBESToSubmitThisJobTo
JobDefinition actualAtomicJobToSubmit
ValuationTerm[] descriptionOfQoSPriceEtc
(i.e. the contents of the Candidate) but I know more things will be
needed to make this really work.
The EPS will ask relevant CSG(s) for the candidates for the job
submitted, and will then evaluate the policy to pick the best place to
submit the job to. The EPS will not submit the job. The EPS *will*
secure any reservations/holds required to carry out the selected
candidate.
However, an EPS really only becomes interesting when we move away from
looking at single jobs; it's within the context of a workflow that
having a service instead of doing it all by hand makes real sense. At
least in my opinion. And I don't think we want to develop a workflow in
this group!
OK, that's my thoughts for now. Any opinions?
Donal.
