[SAGA-RG] minutes from the SAGA-WG session at OGF23, Barcelona

[Thilo Kielmann]

Taken by Andre Luckow of Potsdam University, Germany.
Big thanks!





SAGA General/Working Session Notes
Tuesday, June 3rd, 2008, 11-12.30 am,

Session Chairs: Shantenu Jha, Thilo Kielmann

1.) Introduction (S. Jha):
Shantenu welcomed all attendees with a short overview of the agenda.

2.) SAGA in a Nutshell (T. Kielmann, Vrije Universiteit, Netherlands):

Thilo Kielmann gave an overview of the motivation of SAGA, the
functionality and structure of the SAGA  API. The idea of SAGA is to
create a simple, integrated, stable, uniform and high-level (i.e. at
the right level for applications) API. The API aims to abstract the
complexity of current Grid middleware platforms, which is mainly
caused by the Web service environment.  Based on a file copy and job
submission example Thilo clearly showed the simplicity and power of the
SAGA API.

SAGA is structured into two set of packages: the functional and the
look-and-feel packages. The functional packages provide a simple
access to Grid middleware services, such as file transfer, job
submission, replica managements etc. Look-and-feel packages address
non-functional aspects, such as authentication, authorization, and
monitoring. At the same time, the API provides an abstraction layer to
different Grid middleware platforms. The C++ as well as the Java
reference implementation provide an adaptor mechanisms, which is used
to encapsulate middleware specific code.  With this functionality
applications can use the same API independent from the underlying
middleware. The SAGA API enables the developer to easily integrate
their application with Grid infrastructures: applications can easily
spawn tasks or move files using SAGA.

3.) JSAGA: Using SAGA for Uniform Access to Heterogeneous Grid
Infrastructures (Sylvain Reynaud, IN2P3, France)

The main challenge addressed by this talk is the integration of
various heterogeneous Grid resources from EGEE, OpenPlat, and the
OpenScience Grid in different project of the CC-IN2P3.
JSAGA is an open source implementation of the JAVA SAGA bindings,
which was developed to provide a unified access to these resources.
The main focus of the implementation is the execution management of
computational jobs and file transfer. Other functional packages are
currently not implemented.

JSAGA provides the possibility to introduce plugins at different
layers of the architectures. All plugins are orchestrated by the JSAGA
 engine.
To meet all use cases it was necessary several extension to SAGA have
been necessary. For example, JSAGA supports several job description
language (in addition to the job_description class of SAGA), such as
JSDL, RSL and its own proprietary language.

The author concludes that SAGA is suitable for most of the need, but
to support all use cases, e.g. the automatic staging of files, some
extensions in form of additional methods, attributes and flags have
been necessary. Another issue addressed by the presenter is the state
model for SAGA jobs: JSAGA had to introduced the state queuing to
solve its use case.

JSAGA is successfully used in several tools at IN2P3 and is available
under LGPL at the following location: http://grid.in2p3.fr/jsaga/.


4.) Implementation status, future direction, Discussion (S. Jha)
The session was concluded with a short discussion about the usage and
requirements of other session participants. In general, SAGA is very
interesting for most participants. Several questions regarding the
availability and functionality of the different Grid middleware
adaptors have been addressed. Shantenu concluded the session with a
short project status and timeline.


TODO:
- Issue with URL class in SAGA Java bindings should be resolved in
current release candidate (Sylvain, Thilo)
- To increase the interoperability between the Java SAGA
implementations and enable the reuse of adaptors it was decided to
schedule an SAGA Adaptor API standardization session at OGF24 (Thilo,
Sylvain).

-- 
Thilo Kielmann                                 http://www.cs.vu.nl/~kielmann/