[glue-wg] GLUE2.0's Computing Element

[Laurence Field]

Hi Gerson,

The schema is in an early draft state and therefore might still need a 
little work to get it into good shape. If you have any suggestions on 
how to improve the schema or can see any problems please let us know. I 
will try an answer you question based on what I understand of the 
current draft.

What is important is to first understand the entities that we are 
dealing with and the relationships between them.

For me a cluster represents a set of resources that are managed, which 
essentially is a batch system with a master server. The queue represents 
two things; an end point and a policy.  The GRAM service is an interface 
to the batch system and therefore an end point.

How you represent these things depends on the implementation.

1) If the job attributes are passed to the batch system, then based on 
these it should decide which queue (policy) best matches the 
requirements. In such a scenario,
you would then publish two services (end points), one for each batch 
system, and the gateway should route the job to the relevant batch 
system based on which service (end point) was used.

2) If the the job requirements are not passed though, then you have to 
consider each queue to be a different endpoint and hence have a service 
(end point) per batch system and per queue (policy). The gateway would 
then route the job also to the correct queue.

In either case the policy (queue) would be advertised as a share. 
However, in the second case I am not sure how the end point is linked to 
the policy.


Laurence





Gerson Galang wrote:
> Hi all,
>
> Can you show me how to represent the setup I have below using the new 
> structure of the GLUE 2.0 entities?
>
> - our site manages 2 clusters
> - each cluster runs a PBS queuing system
> - each queueing system manages three queues: small, medium, large
> - globus is installed on a separate box -- called the gateway box. we 
> run only one instance of the GRAM service on this box. anyone running 
> a grid job at our site will have to specify the 
> name-of-queue at name-of-pbs-server in the queue element of their RSL to 
> pick which queue they want to submit their jobs to.
>
> It is not mentioned anywhere in the InitialSketch wiki ( 
> http://forge.gridforum.org/sf/wiki/do/viewPage/projects.glue-wg/wiki/InitialSketchOnEntities) 
> that the CE is still an abstraction of a queue. The relationship of a 
> ComputingService to a CE is also many to one which makes it hard for 
> one GRAM service to be able to submit jobs to a number of CEs (if ever 
> a CE is still equivalent to a queue). Does this mean that we will have 
> redundant info for the ComputingResource, ExecutionEnvironment, and 
> ApplicationEnvironment for every GRAM service (for each queue) we 
> provide?
>
> Is it safe to assume that the ComputingResource, ExecutionEnvironment, 
> and ApplicationEnvironment entities in GLUE 2.0 are equivalent to the 
> Cluster, SubCluster and Software entities of GLUE 1.3 respectively?
>
> You have a comment in the form of a question under the "element" 
> section of the wiki which says: "can we have multiple resources 
> (computing resources <=> clusters) served by the same service 
> instance?". My answer is yes and isn't my use case above an example of it?
>
> Thanks,
> Gerson
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