Open Grid Forum 22 Report
Omer Rana (GridNet ID: 107 and 133)
Cardiff University
This report provides an overview of my involvement in research and working
groups at the Open Grid Forum (OGF) 22 meeting in Cambridge (Mass), USA
– February 25-28, 2008. A significant focus in this particular OGF was on
application users, and how they are currently making use of Grid computing
technologies. I participated in the following activities:
• Participant: GRAAP working group sessions
• Participant: “Enterprise Adoption: Enabling the Next Generation IT Infrastructure” workshop
• Participant: “Financial Services” workshop
• Participant: Cloud Computing BoF
• Participant: “Data Management” workshop
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GRAAP
The GRAAP working group involved three sessions – focusing on two main
themes: (i) interoperability between two WS-Agreement implementations; (ii)
a re-negotiation protocol. The interoperability session began with a presentation by Oliver Wäldrich on comparing two WS-Agreement implementations, one
from the Fraunhofer institute and the other from the Technical University of
Berlin. The aim was to demonstrate that two versions of WS-Agreement could
work together, even though they did not make use of a common code base. Each
implementation also made use of the agreement states discussed in the specification, and would also test the factory service used to create a new agreement
template. As WS-Agreement made use of other Web Service standards such
as WS-Naming and WSRF, it was apparent during this discussion that it was
actually interoperability between naming conventions that had been the key
stumbling block in undertaking interoperation. A proxy was used to support
the translation between the two naming schemes in the demonstration provided
by Oliver. It was therefore realized that additional work was needed to identify
what precisely constituted WS-Agreement interoperability, and the approach
adopted by other working groups – such as GIN – would be considered. The
key idea would be to develop a client-server application, where Service Level
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Agreements (SLAs) encoded using WS-Agreement would be sent to the server
to validate their conformance to the specification.
The re-negotiation session focused on discussion around a paper: “A Contract Re-negotiation Protocol”, that had previously been submitted by Michael
Parkin, Peer Hasselmeyer, Bastian Koller and Philipp Wieder – as part of
work being undertaken in the European NEXTGrid/BREIN projects. The
paper discussed a re-negotiation protocol that could be utilized in environments where messages could be delayed. The authors argued that the approach
adopted within the WS-Agreement specification (and subsequent discussions in
the GRAAP working group) focused on maintaining strong consistency of state
using transactional protocols using a two phase commit approach. The authors
proposed that such an approach was wasteful of resources and could also lead to
their under utilization. They also indicated that such an approach would be difficult of use in environments where messages could be delayed, or where strong
legal constraints needed to be satisfied. They, instead, proposed a protocol
that utilized loose consistency. A very simple state machine representation, and
the associated messages that were needed within the protocol were discussed.
Overall, the proposal received good feedback during the session, although there
was no general agreement if this particular protocol should be adopted within
a future version of WS-Agreement. Negotiation issues remain important concerns for the GRAAP working group, although due to the diverging views on
the associated protocols, no particular approach has been accepted.
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Enterprise Adoption, Financial Services and
Data Management
The Enterprise Adoption and Financial Services workshops had a significant
overlap in speakers and themes. Both workshops focused on how various industrial users were making use of Grid computing in-house – ranging from the
use of Condor to specialist data storage facilities. It was clear from listening to
the speakers that what constituted Grid computing for many of these industries
differed significantly. Some people referred to their Data Center as being a Grid,
whereas others considered such a definition to encompass a small/specialist cluster.
John Barr from the 451 Group provided a useful survey about the particular
industry sectors that were interested/using Grid computing. His discussion of an
API to support the financial services industry provided a useful integration point
for common services that could be made available over a Grid infrastructure.
However, he also mentioned that many in the financial services community
were happy to agree on common infrastructure standards, but were reluctant
to identify specialist services that they made available to their in-house users.
Consequently, the API for financial services that he was intending to develop
did not get traction in the business world, and had to be abandoned.
The data management workshop primarily focused on work from the Stor-
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age Network Industry Association (SNIA), and their work on standards such as
parallel NFS (in association with the IETF) and XAM. There was also discussion about supporting data management at different levels in the Grid – from
information models for knowledge management, to the lower level resource management that was the focus of SNIA.
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Cloud Computing
Geoffrey Fox led a BoF on Cloud Computing, and the benefits that such a
technology could bring. He identified the “Cloud” as being a coarse grained
abstraction compared to the “Service” abstraction. Interaction between Clouds
would therefore involve looser coupling than between Services. The exact distinction, however, was not clear to me – as much of the work in Services was
already attempting to address some of the concerns that Geoffrey raised.
Prior to the BoF was a keynote from IBM about utilizing the Cloud abstraction to create better resource “ensembles” – and creating high speed interconnection networks that would link these ensembles. The BoF identified the
formation of a Inter- and Intra-Grids, emphasising the considerable industry
benefits that could arise from linking such infrastructure together, using high
speed networks. Existing focus of vendors such as Amazon in their S3 and EC2
Cloud offerings indicates industry interest.
The aim of the BoF was to create a new activity at the OGF to focus on
this emerging technology. This is likely to be a useful new direction for the
OGF. It would be useful for the OGF community to investigate the validity
of the current standards they propose in the context of such Cloud computing
infrastructure. I do not believe significant differences exist at the present time
– although future interoperability standards in Cloud computing may prove to
be different from those in Web Services.
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