[glue-wg] GLUE for describing resource requests (use case DGSI)

[Sergio Andreozzi]

Hi Alexander,

the final XSD for GLUE 2.0 is expected by the end of the year.

Concerning the integration with JSDL for resource requirements matching,
this is still open to debate and falls in the area of PGI work.

Nevertheless, the topic has been touched few times in the past. I can
provide my vision:

the current JSDL envisions a number of terms to be used to express
requirements on resources. They are part of the JSDL specification therefore
binding the resource description to the job description. A couple of years
ago, in an OGF joint session (http://bit.ly/byqg5T), we discussed the idea
of separating them in order to easy the evolution of resource
models independently from JSDL. Requirements are usually expressed as
constraints on resource properties, therefore the idea could be to enable to
express them as XPath/XQuery expressions on the resource description. An
example is given in Section 5.3 of this OGF document:
http://ogf.org/documents/GFD.137.pdf

Expressing requirements as constraints on a resource description is the
approach in place since years in the ClassAd language and its gLite JDL
derivation. XPath/XQuery can be a translation into an XML world.

Cheers, Sergio


On 18 November 2010 14:17, <alexander.papaspyrou at tu-dortmund.de> wrote:

> Sergio,
>
> I think this boils down to more or less the old "allow fragments of GLUE to
> be used independently" debate we had in Brussels. Do we have a timeline for
> a version bump of the XML/XSD rendering, and will it be possible to render
> the XSD as it was done in JSDL (i.e. having an "xs:element" for each
> "xs:*Type*")?
>
> Best,
> Alexander
>
> Am 18.11.2010 um 12:27 schrieb Mikael Högqvist:
>
> > Hi,
> >
> > I'm working in the DGSI project (a German D-Grid project) where our
> > goal is to design and implement an interoperability framework between
> > community schedulers and community bound resources. More specifically,
> > this include protocols and services for delegation of activities as
> > well as resources. We are primarily basing our protocols on OGF
> > standards and recommendations and have tight collaboration with both
> > the GRAAP (WS-Agreement/Negotiation) and DCI-Fed working groups within
> > OGF.
> >
> > In the first information model we decided to use GLUE 2.0 for both
> > resource descriptions and resource request specification. However
> > describing resource requests with GLUE turned out to be difficult to
> > implement. The main issue that we have is the restrictions in the GLUE
> > 2.0 XML schema which makes it difficult to use only specific
> > elements/group of elements in a document instance.
> >
> > For example, we would like to use the AccessPolicy element to describe
> > requirements on who (e.g. DN/VO) is authorized to access a delegated
> > resource. But to use this element, we need to create the entire
> > hierarchy with Service/ComputingService/ComputingEndpoint and their
> > respective required elements (e.g. ID, QualityLevel, ...) when using
> > the GLUE 2.0 XSD.
> >
> > Currently, our solution is to use JSDL for specifying both activity
> > and resource delegation requests. However, JSDL is not sufficient for
> > all our use cases/requirements and we would like to use GLUE for
> > specifying resource requests in our next version.
> >
> > Is there any work going on in the glue-wg to make the XSD rendering
> > more lenient towards other use cases such as resource requirement
> > specification? Or making it possible to use a subset of GLUE and
> > combine it with other info models such as JSDL?
> >
> > Thank you in advance and Best Regards,
> > Mikael Högqvist
>
>


-- 
Sergio Andreozzi - Policy Development Manager
EGI.eu - Amsterdam - The Netherlands - http://egi.eu
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