Concepts and Architecture of the Grid Summary of Grid 2 Chapter 4 Concepts of Grid Mantra Coordinated resource sharing and problem solving in dynamic multi institutional virtual organizations Allows for resources to be shared by mistrustful participants with varying degrees of prior relationship Virtual Organization VO formed by a set individuals institutions defined by the sharing rules Nick Rutar and David Wang CMSC 818 The Sharing Relationship Policy Who can access what when Resource owner makes available subject to various constraints Security concerns Qualification of requestor resource owner has enough budget etc Server Client and Peer to Peer coordinated resource sharing dynamic relationship Resource use may vary in different contexts Achieving various qualities of service response time throughput etc Nick Rutar and David Wang CMSC 818 Evolution of Grid Technologies Custom solutions early 90s Grid exploration work Applications built directly on Internet protocols Limited functionality in terms of security scalability robustness Globus Toolkit version 2 GT2 1997 Open Source Quickly became the standard for Grid Computing Defined and implemented standard protocols API s and services Open Grid Services Architecture OGSA 2002 Community standard with multiple implementations OGSA based GT 3 0 released in 2003 Built on GT2 concepts and technologies Service oriented architecture and based on Web services Managed Shared Virtual Systems Nick Rutar and David Wang CMSC 818 The Grid Vision Grid A system that coordinates distributed resources using standard open general purpose protocols and interfaces to deliver nontrivial qualities of service Coordinates distributed Resources Resources and users under different domains Desktop vs central computing Different administrative units of the same company Standard Open General Purpose Protocols and Interfaces Issues like authentication authorization Important they are standard and open Deliver nontrivial qualities of service Response time throughput availability security Nick Rutar and David Wang CMSC 818 Grid Model Grid based on the hour glass model Thin center few standards Wide top many high level behaviors can be mapped Wide bottom many underlying technologies Nick Rutar and David Wang CMSC 818 Grid Architecture Requirements for general component classes User applications Collective services Coordinated use of multiple resources Resource connectivity protocols secure access to resources services Fabric individual physical logical resource available in a grid PC Storage Sensors Networks Nick Rutar and David Wang CMSC 818 The Fabric Layer Implements local resource specific operations e g NFS storage access protocol Introspection mechanisms and management mechanisms for Computational resources Storage resources Network resources Nick Rutar and David Wang CMSC 818 Connectivity Layer Tasks include transport routing naming Some security requirements Single sign on one sign on for all resources Delegation user delegates privilege to processes processes delegates to other processes Integration with local security solutions allow interoperability between global and local security policies User based trust relationship trust based on user not the resource providers Nick Rutar and David Wang CMSC 818 Resource Layer Builds on connectivity layer communication and authentication protocols 2 major classes of resource protocols Information protocols obtaining information about a certain resource e g load usage policy configuration Management protocols negotiating access to a shared resource presenting requirements and operations to be performed etc Nick Rutar and David Wang CMSC 818 Collective Layer Provides means to coordinate the sharing behaviors Directory services Coallocation scheduling brokering services Monitoring and diagnostics services Data replication services Tools define invoke collective layer functions Grid enabled programming services Workflow Systems Software discovery services Collaboratory services Addresses security policy and accounting issues Community authorization servers enforces community policies Community accounting and payment services Nick Rutar and David Wang CMSC 818 Applications Constructed in terms of services defined at any layer May call on sophisticated libraries and frameworks which may themselves define protocols services and APIs Nick Rutar and David Wang CMSC 818 Grid Implementation GT 2 Address issues of security information discovery resource management data management communication fault detection and portability Fabric Layer Leaves most local operations to each local resource However does include components interfacing to resource level protocols Including advanced reservation capabilities GARA PBS Condor etc Connectivity Layer based on Grid Security Infrastructure GSI which is based on PKI Single Sign on uses Proxy Credential digitally signed certificate This certificate allows the holder to perform operations on behalf of the signer Delegation remote services use the proxy credential to act on behalf of the user Nick Rutar and David Wang CMSC 818 Grid Implementation GT 2 Resource Layer Uses Grid Resource Allocation and Management GRAM protocol Uses Monitoring and Discovery Services MDS 2 Discovering accessing configuration and status info Uses GridFTP extended FTP Allows partial file access management of parallelism for highspeed transfers Collective and Tools Limited number of collective layer capabilities from GT2 Many are developed by others Nick Rutar and David Wang CMSC 818 OGSA Open Grid Services Architecture Significant redesign of GT2 Factoring component behaviors of GT2 Enabling uniform treatment of all network entities for service orientation Aligning with Web services usage of Web Service Description Language WSDL Sees Grid service as a Web service Builds on OGSI s defined interfaces and behaviors Nick Rutar and David Wang CMSC 818 The Grid Community Global Grid Forum GGF Coordinates grass roots and government sponsored efforts in many countries Draws 1 3 of its participants from the industry Participation increased ten folds since 1998 Nick Rutar and David Wang CMSC 818 Future Directions Need to refine OGSA model and develop additional building block services Need for program development and execution tools compilers debuggers etc Scaling more entities smaller devices Nick Rutar and David Wang CMSC 818