OGF 20: May 7-11 2007, Manchester, UK
Attendees: A Stephen McGough, Vesselin Novov
Main groups of focus: Joint session Information modelling and computing resources,
JSDL, HPC Profile, OGSA Workflow, Workflow sharing, Grid Scheduling Architecture,
OGSA BES, OGSA RUS, OGSA EMS, GridNet meeting, OGSA RSS, Service Level
Terms, AuthZ, Grid in the Distributed Computing Landscape, OGSA f2f
The joint session on information modelling and computing resources was healed to bring
together those people from the OGSA information modelling/resource management
design team, the GLUE group and the Reference Model group. As these groups are now
all working on similar areas it is essential to prevent duplication of work. The groups
were asked to describe what their work was and how it would fit together with the other
emerging standards. In all three cases JSDL, and BES, were identified as things that they
would wish to interact with. This shows that JSDL and BES now have major adoption
within the Grid community. Most groups are now feeding their requirements into the
JSDL work and will help in the development of JSDL 2.0. As this work is highly relevant
for our development of GridSAM we were active within this session and will be
following up on this effort.
For the JSDL sessions we now have two documents in public comment: the HPC profile
application draft and the parallel application (SPMD) extension. There was therefore a
reach out effort at this OGF to encourage people to read these documents. For the JSDL
1.0 errata we had feedback from a new project which had implemented JSDL
(KnowARC) this brings to eleven the number of known implementations. This lead to
some new tracker items and some of the existing tracker items being resolved. In most
cases this was by tightening the definitions within the document based on feedback.
During the second session the ideas behind using XQuery were presented to the group
along with proof of concept examples showing that they could be used in this context.
The parameter sweep extension was discussed further. In our final session we discussed
the JSDL 2.0 extension. During the opening session of OGF 20 the JSDL group was
awarded with the Open Grid Forum Leadership Award. This award is given out to
individuals or groups within the OGF for outstanding leadership and many contributions
to the OGF mission. This was a significant acknowledgement from the community of the
significance and the value of the work we have achieved.
The HPC Profile group are now working hard on producing the implementation
experiences document. This is an area that we are active within both as developers of
JSDL and BES but also as active members of the interoperation activity at SC06.
In the OGSA Workflow session the two approaches (use existing workflow tools and
design own workflow language) were further discussed. Some scoping activity was
carried out on the group. Error handling was placed out of scope while error detection
was in scope. Graphical representations and cyclic declarations were also placed out of
scope. The idea of using BPEL over JSDL was proposed and the OMII-BPEL project
was presented which uses GridSAM as an endpoint for BPEL activities. It was asked “if
we just endorse BPEL who will complain?”, though this did not receive unanimous
support. It was decided that a survey of existing activity was required before this work
could continue further. This work fits nicely in with our BES/JSDL work, but also with
our general workflow/components work we are doing as part of the ICENI II
development.
By contrast the Workflow sharing session was more concerned with how workflows
could be shared between Grid infrastructures. This could be through workflow translation
or the ability of one workflow system to execute a workflow in a different architecture.
This is again relevant due to our work on the ICENI II development.
The Grid Scheduling Architecture group are working on interoperability of Grid
scheduling entities. This is significant for our work with JSDL and BES as a scheduling
entity would be the service built above a BES instance. We were able to contribute our
knowledge from GridSAM, BES and JSDL into this work.
For OGSA BES the effort is now towards writing an experience document. This is
something that we are contributing towards.
The OGSA RUS has been inactive for some time as it had already published a
specification. However, in light of changes within the community, the development of
new standards and implementation experience has lead to the group being revived for
update. Through prior work (carried out by William Lee) we have feedback to give in
these regards and have been active in this area. Much of discussions in the OGSA RUSWG session emphasized some fundamental scalability problems occurring with very
large data sets of usage records and their transfer between clients and services and
improvements of the RUS and UR specifications in that respect. We shared similar
experience we had through the development of GridRUS. The GridRUS project was
funded by OMII-UK Managed Program. It is effectively a prototype implementation of
the RUS draft specification providing query-able persistent storage of Usage Records.
Like the services developed by some of the other participating groups, GridRUS is a WSI-compliant web service, therefore prone to the discussed workload problems. However,
much of the advantages GridRUS rest in its modular architecture which allows different
components to be configured and used separately if need by the user. The project suite
consists of; the core engine providing a Java API for managing persistence and query of
usage records job launching and file staging plugins; a web service implementing the
Resource Usage Service specification; a package of client APIs and command-line tools
for inserting or querying usage records stored in a RU Service and a package of XML to
Java bound classes representing the RU Service and Usage Record schemas. Should
OMII-UK decide to fund further any development effort in this project, GridRUS would
be in a very good position to become one of the first fully compliant RUS
implementations and a benchmark product giving its highly flexible and reusable
architecture.
The OGSA EMS group are focusing on how to discover information about the Grid for
such things as job submission. In their model jobs are described in JSDL and submitted to
a BES instance. The work of the group is now to define how information can be obtained
to achieve this. This is highly relavent work as it fits in with GridSAM and the work on
BES and JSDL.
As this event was UK based and as such most, if not all, GridNet funded people would be
attending there was a GridNet meeting held in Manchester. This was to check up on the
status of GridNet spending and to determine how to continue the effort of GridNet and
promote its achievements. During this meeting Omer Rana and Stephen McGough were
tasked with organising a GridNet workshop at the next OGF meeting.
The OGSA RSS group is working on the problem of how to select the resources to use
within the Grid. This relies heavily on the JSDL description which can be used by the
candidate set generator to list those resources which can execute the JSDL (based on
resource requirements). This is again another scenario where JSDL is being used within
the Grid architecture.
The Service Level Terms BoF was held as a follow up to the QoS BoF held at the
previous OGF meeting. The intention of this BoF was to scope down significantly those
terms that would be needed when discussing job submissions and file transfers (BES and
ByteIO). This is significant work as it is something that we could make use of for future
versions of GridSAM.
At the end of the main OGF event a one day OGSA f2f was held. The relevant items in
this meeting are provided below. The OGSA EMS Scenarios document is now complete.
This discusses how to submit jobs to the Grid and relies on JSDL and BES. The
workflow discussion from earlier in the week was continued. It was pointed out that other
standards bodies exist and other workflow standards exist along with BPEL such as
XPDL – though this is more abstract in nature. Examples of other systems were given
including Microsoft WF. In conclusion it was felt that a primer/best practices document
was most appropriate. This is something that we will be feeding into.
Over the period of two AuthZ-WG sessions we reviewed the status of some previously
proposed and some new profile specifications. More text was added to the XACML
Profile to cover obligations. The text explained exactly how gridmap files could be
replaced with obligations, and how coordination decision making could be enabled with
obligations. The model and diagrams of the WS Trust Profile were updated and made
more generic. Protocol flows were still left the same but more possibilities were allowed.
Some of the effort was allocated to the definition of the SAML V2.0 Profile for Virtual
Organization attributes. Attribute names to include now Virtual Organization, Group and
Role - essentially replicating the attributes from the XACML Attribute Profile. Of much
interest, related to our OMII Authorization project, were the reviews of a couple of
authorization services which implementations follow the XACML specification. G-Pbox
- an authorization service based in in gLite, had taken an approach similar to the one in
our OMII AuthZ application; one of its main component is an XACML compliant Policy
Decision Point and the service interface processes xacml-context:Request against a
repository of XACML policies and returns and xacml-context:Response. The shared
similarities with other projects gives us the confidence that our OMII AuthZ service
project is evolving in a direction which might in the near future allow us to take part in a
wider effort of testing/demonstrating interoperable authorization services between
EGEE, OSG, Globus and OMII. The GridShib Project continued its focus on a hybrid
security token called X.509-bound SAML Token, i.e. a SAML assertion bound to an
X.509 certificate. It would be either a short-lived end-entity certificate or a proxy
certificate. The resulting "X.509-bound SAML Token Profile" would be a
straightforward extension of the WS-Security X.509 Token Profile, and therefore an
implementation of the latter would be automatically an implementation of the former.
Grid in the Distributed Computing Landscape – a generally informative session on
current state of Grid. The session explored the way grid infrastructure solutions had been
used by organizations around the world to enable the modern knowledge-based, global
economy. The discussion reviewed the role of grid technologies within the broader realm
of distributed computing and defined the common categories of grid use today. The
presentation traced through the milestones of the evolution of grid technologies from
application-specific solutions to dynamic, shared and service-oriented infrastructures.
The session's main focus was on a number of major trends in the use of grids today; the
use of the infrastructure to reduce cost of operation, increase efficiency, optimization and
interoperability; the use of the infrastructure to manage workload and services across
multiple business units within an organization; the use of the infrastructure to enable
inter-organizational service-oriented collaboration as within the boundaries of virtual
organizations through the adoption of common standards and practices.