# Presentation: 125873

## A Grid Services Framework for Collaborative Applications

- Kaizar Amin
- Sandeep Nijsure
- Gregor von Laszewski
- Mathematics and Computer Science Division (MCS)
- Argonne National Laboratory

## Roadmap

- Introduction
- Services-based Architecture for the Grid
- Collaborative Framework
- Technologies in use
- Application
- Active Thermochemical Tables

## Introduction

- Computational Grids enable resource sharing, coordinated and  interactive problem solving across multi-institutional domains in a secure context.
- For example:
- A biologist can exploit thousands of computers to analyze DNA and Gene Mapping
- A group of Thermochemists collaborate to discuss thermochemistry data of some new species.

## Future of the Grid

- A large number of major Grid projects in scientific & technical computing/research, education, and business.
- Services-based Architecture
- Building block: **Service**
- Collection of platform-independent services that are described by a service description language.
- Services publish their interfaces to some online directory or registry of services.
-  Services are discovered by querying the service directories or registries.
- They are Invoked by using appropriate binding protocols.
- The services-oriented concept lends itself to an architecture that requires interoperability across heterogeneous platforms and exposes all or part of its applications on different machines, platforms, and domains.
**Ideally suited for the Grid**

## Web Services

- Standard-based framework defined by the W3C and contributed by IBM, Microsoft, and others.
- Described using the Web Services Description Language (WSDL).
- Published and Discovered using the Web Service Invocation Language (WSIL) or the Universal Description, Discovery, and Integration (UDDI).
- Uses XML-based Simple Object Access Protocol (SOAP) as its binding protocol.

## Grid Services

- Web services support creation, discovery and invocation of persistent services.
- Grid architecture requires creation and maintenance of transient services.
**Grid services**: extends the functionality of Web services to support (potentially) transient service instances.
- Grid services are defined by the Global Grid Forum (GGF) as a part of the Open Grid Services Architecture (OGSA).

## Open Grid Services Architecture (OGSA)	

- Provides an extensible framework of core services that support Grid functionalities by combining the realms of Web services and Grid technologies.
- Building block - Grid Service
- A potentially transient Web Service that conforms to a set of predefined conventions defined by the Global Grid Forum (GGF)
- Enhances the capabilities of a conventional Web Service framework by providing:
- Instance/Lifetime Management
- Notification subscription (peer-to-per communication)
- Advanced Registration and Discovery
- GSI Security

## Active Thermochemical Tables(ATcT)

- Active Thermochemical Tables(ATcT)

- Thermochemistry finds applications in disciplines such as earth science and engineering.
- Until now, the data necessary for thermochemical calculations has been available only in static table form, and the algorithms to derive accurate model descriptions have been too imprecise to deal with the complex chemical reactions.

## Active Thermochemical Tables(ATcT) ...

- Active Thermochemical Tables(ATcT) ...

- ATcT provides an efficient algorithm whereby the static tables are scanned into an “Active” database of thermochemistry data.
- To obtain the thermochemistry data of any new species the chemist inputs a complex chemical reaction table.
- ATcT generates a chemical network/graph from the input file.
- Solving this chemical network  results in the optimization of the thermo chemistry data for a particular species.

## Active Thermochemical Tables(ATcT) ...

- Requirements:
- Chemists can interactively formulate complex sets of chemical reactions based on their data-sets and then collaboratively steer the application to view new thermochemistry data.
- Users have their individual thermochemistry data online on WebDAV servers. Based on the collaborative interaction, they can exchange their individual thermochemistry data or consume the newly disseminated information.
- The application must allow the formation of dynamic collaborative groups in a secure environment without compromising intellectual properties.
- Chemists that collaborate in the formulation of new thermochemistry data should be able to simulate their previous discussions in order to investigate certain important issues at a later time.

## Open Collaborative Grid Services Architecture (OCGSA)

- OGSA provides a set of core services that can be extended to implement high-level services for a  wide variety of applications (including collaborative applications).
- Nevertheless, rather than developing certain key high-level components for every collaborative application, we propose a framework of components that  can be inherited by any stand-alone application or Grid service with minimum effort to transform itself into a collaborative Grid service.
- This framework is called the Open Collaborative Grid Services Architecture (OCGSA).
- OCGSA builds around the notion of a collaborative Grid service; that provides the necessary interface to interact with other OCGSA components.

## Open Collaborative Grid Services Architecture (OCGSA) ...

## Collaborative Grid Service

- OCGSA introduces the notion of *collaborative Grid service*:
-  a Grid service with a set of predefined metadata elements and behaviors.
- A collaborative Grid service defines metadata regarding the creator, name, description, and current members of the group.
- It also provides the interface to handle security policies at different levels of the application (application level and group level), basic community chat facilities, an adequate presence management for users, capabilities for interactively controlling and steering the applications.

## Grid Security Service

- OCGSA uses security mechanisms such as authentication, delegation of rights, confidentiality, and message integrity as specified in the OGSA security draft.
- However, the security service of OCGSA provides an advanced multi-level policy based authorization.
- On the first level, the *application level*, the application service provider dictates the authorization policy regarding the users that can access the application.
- The second level is the *group level* access control where group creator specifies the authorization policy describing the class of users that can participate in the group.
- OCGSA provides mechanisms that allow users to define and enforce such authorization policies dynamically at runtime without any prior configuration support.

## Grid Registration Service

- OCGSA framework requires that every collaborative service be associated with a registration service so that group instances can be discovered by peer users.
- The registration service used in OCGSA is a registration Grid service provided by OGSA, capable of supporting XPath/XQuery queries.
- Support for such a sophisticated querying mechanism is essential because OCGSA enables arbitrary users with appropriate credentials to query the registration service based on complex criteria and identify the service instance (group) that they would like to join.

## Grid Database Service

- The database service provides a Grid service interface to a Native XML Database (NXD) defined by the XML:DB initiative.
-  This enables the enforcement of dynamic security policies on XML databases used in collaborative applications.
- Using the database service, users can store arbitrary data in XML format and later retrieve it using XPath queries.

## Grid Event Logging Service

- The event logging service uses the Grid database service to  provide an interface to log the messages or events communicated between online users of a group into a persistent database.
- Users that join a particular group at a later time can retrieve these events, thereby updating themselves about the group's prior activities.
- The event archiving mechanism also enables the group members to insert checkpoints into the event database and replay the entire or sections of the archived collaborative activity when the group is off-line.

## Active Thermochemical Tables(ATcT)...

## Active Thermochemical Tables(ATcT)...

## Active Thermochemical Tables(ATcT)...

## Acknowledgement

- This work was performed under the auspices of the U.S. Department of Energy, Office of Advanced Scientific Computing, SciDAC program, under contract no. FWP #56825.

## References

- Kaizar Amin, Sandeep Nijsure, Gregor von Laszewski. Open Collaborative Grid Services Architecture. In EuroWeb 2002conference, Oxford, UK, 17 Dec 2002.
- Gregor von Laszewski, Branko Ruscic, Patrick Wagstrom, Sriram Krishnan, Kaizar Amin, Sandeep Nijsure, Reinhardt Pinzon, Melita L. Morton, Sandra Bittner, Mike Minkoff, Al Wagner, and John C. Hewson. A Grid Service Based Active Thermochemical Table Framework. In *Third International Workshop on Grid Computing*, Lecture Notes in Computer Science, Baltimore, MD, 18 Nov. 2002.
- B. Ruscic, M. Litorja, and R. L. Asher. Ionization Energy of Methylene Revisited: Improved Values for the Enthalpy of Formation of CH2 and the Bond Energy of CH3 via Simultaneous Solution of the Local Thermochemical Network. *J. Phys. Chem. A.*, 103:8625–8633, 1999.
- Gregor von Laszewski, Ian Foster, Jarek Gawor, and Peter Lane. A Java Commodity Grid Kit.  *Concurrency and Computation: Practice and Experience*, 13(8-9):643-662, 2001.  http://www.globus.org/cog/

## Thank you

- QUESTIONS !!