OGSA 18: August 13-15 2007, Sunnyvale, CA
Attendees: A Stephen McGough, Vesselin Novov
Main groups of focus: Information Modelling, AuthN, EMS Scenario, JSDL, Worlflow,
Service Level Terms
In the Information Modelling session a discussion was held as to how the CIM, DM and
GLUE models inter-act with each other; also feeding into this are the JSDL specification
and the BES model. The relationship between these entities was defined and discussion
ensued as to how we can bring entities such as jobs and resources together. This lead onto
a discussion as to how JSDL 2.0 could be developed to have capabilities and
requirements which would match with similar capabilities and requirements of the
resource. It was decided that the requirements can be defined into two parts actual
requirements and ranking/preferences. It was felt that at the current stage it would be best
to limit this just to the actual requirements and that ranking of the possible matches could
be done at a later stage. The idea of two-way matching (where both the consumer and
provider have requirements which are adhered to) as opposed to one way matching was
discussed. Again the idea was to limit ourselves initially to just one way matching as this
would be simpler. The discussion moved onto how to achieve this with XQuery being
proposed as a prime candidate. The consensus was that JSDL should work on its
extension for matching using XQuery as a test-case for this approach. This was an
interesting session from both a JSDL point of view, as we were significant players in the
session, but also for GridSAM as this is an area we would be developing GridSAM into.
The AuthN group are hitting up against the problem that most organisations and
companies have already implemented their own security infrastructure and as such are
unlikely to change this in the short term (if at all). This makes the chance for easy
interoperation slight. This is a major problem for Grid adoption as without a common
security model interoperation at any other level is a major problem. Work is ongoing to
see if a common “simple” case can be defined.
The EMS scenarios document has been published but is now looking outdated as it is
based on old versions of some of the specifications and some specifications don’t seem to
be active any more. The original document focused on job submission (BES/JSDL) and
the deployment of software using CDDLM. However, CDDLM has not had take-up
within the community (in many cases being considered to complex to implement). As
such the intentions are to revise the document to take account of HPCP and replace
CDDLM with other standards where ones exist. Or in the lest case provide examples of
“simple” ways to do this – such as transferring a zip (tar) file to the endpoint and
expanding before executing the code. This also requires the addition of file staging
scenarios within the document. Other changes would include update of the Resource
Selection Service text and revision of the Information Service in light with the recent
changes. This is significant work for us both due to our work with BES and JSDL, but
also as these scenarios match closely the scenarios we provide already through GridSAM.
This further shows the major uptake of our work with JSDL/BES within other standards
groups.
For the JSDL session most of the discussion continued from the themes in the previous
sessions. As the work for JSDL is now becoming integral to the overall OGSA
architecture it is difficult now to isolate this work to just its own session. For the JSDL
1.0 errata version we have now managed to resolve 24 out of the 29 open issues and it is
hoped that we will be able to publish this document soon. For the requirements
specification there will be a close synergy with the work happening in the OGSA-RSS
group. As such effort from the JSDL group will go towards helping finish the OGSARSS specification. Work on the XQuery prototyping is progressing well and examples
are being generated.
At the previous OGF it was decided that the OGSA design team on workflow would
conduct a survey of existing uses of workflow. In this session we discussed the possible
scenarios for which we would ask questions and what we would intend to do with the
answers once we had them. It was proposed that we should focus on Web Services based
workflow systems as opposed to just any workflow systems. However, for JSDL many
underlying systems use workflows which are not Web Services. The conclusion was to
make a spreadsheet of know workflow systems and contact users and developers to fill
out the details for the systems they know.
In the Service Level Terms session we followed up to the BoF held at the previous OGF
meeting. It was felt that the best approach would be to offer different tiers of support
based on what the user was willing to “pay” for - such as Bronze, Silver and Gold. These
would be pre-defined tiers that the user would select. This work does not seem ready for
standardisation yet though this information should be captured for future use. Again this
is relevant for the work we are doing with GridSAM.