Globus

Ian Foster and Carl KesselmanArgonne National Laboratory and University of Southern Californiahttp://www.globus.org

Computational GridThe Definition

A distributed computing infrastructure for coordinated resource sharing and problem solving in dynamic multi-institutional virtual organizations

Computational GridExamples

Financial forecasting with ASP and SSPIndustry consortium for feasibility study using multidisciplinary simulationCrisis management responding to oil spillMulti-institutional high-energy physics collaboration for analyzing petabytes of data

Computational GridCharacteristics

Heterogeneous and dynamic environmentDiverse and dynamic resource-sharing relationships across multiple administrative domainsPerformance critical

Computational GridA New Challenge?

Differs from traditional distributed systems Resource sharing vs. Information sharing Peer-to-peer vs. Client/Server Computation vs. Communication

Differs from traditional parallel computing Loosely coupled, heterogeneous, and dynamic

systems Spans over multiple administrative domains

Design Issues

Interoperability vs. Flexibility

Performance vs. Convenience

Local control vs. Global coordination

Design Philosophies

A bag of servicesThe hourglass principle: a balance between interoperability and flexibilityTranslucency: a balance between performance and convenienceLayered design: Enabling global coordination while maintaining local control

Design PhilosophiesThe Hourglass Principle

Design PhilosophiesTranslucency

Managing heterogeneity, not simply hiding it

Transparency for convenience

Exposing certain low-level details to facilitate performance optimization

Design PhilosophiesTranslucency: Examples

Provide ways to discover and control aspects of the underlying system

Reliability or Low latencySecurity or No securityMessage passing, Shared memory, or IP

SP EP

Design PhilosophiesLayered Design

Design PhilosophiesLayered Design: Layers

Fabric: Interfaces to local control

Connectivity: Communicating easily and securely

Resource: Sharing local resources

Collective: Coordinating multiple resources

Applications

Design PhilosophiesLayered Design: Examples

Globus Layers

Conclusion

Computational grid poses challenges that are beyond the current state of art in distributed systems and parallel computingGlobus provides an infrastructure to addressing these issues with interesting design philosophies