Middleware for Grid Computing and the relationship to Middleware at large ECE 1770 : Middleware Systems By: Sepehr (Sep) Seyedi Date: Thurs. January 23, 2003

What is Grid Computing? Definition of the Grid Controlled sharing of geographically distributed resources Virtual Organization Analogy with power grids Consistent, pervasive, dependable, and transparent access to electricity from different sources Characteristics of a Grid No centralized control center Heterogeneity (of resources) Scalability Dynamic and Adaptable

Applications Presented early to see relevance to the design methodologies in grid middleware Classifications of Applications/Uses: Computational Service Inherent part of ALL applications Data Service Scalable storage and access to distributed datasets Application Service Example: like web services Information Service Example: WWW portal Knowledge Service Example: data mining

A Layered View of a Grid Grid Fabric Core Middleware User-level Middleware Grid Application Computers, supercomputers, storage devices, instruments … Process management, co-allocation of resources, storage access, security, information registry and discovery, …. Available as APIs: global resource management: resource brokers, … Core Middleware User-level Middleware Process management, co-allocation of resources, storage access, security, information registry and discovery, …. Available as APIs: global resource management: resource brokers, …

Middleware Overview Components Security Secure communications (SSL) Distributed security infrastructure Manage user credentials to selectingappropriate resources Data Management Transferring data throughout the grid and to users Globus: GridFTP Deals with high-performance, security and reliability Information Management Information DB about resources Availability, capabilities, … Resource Management User-level & Core ASPECTS Many organizations involved ex: Global Grid Forum and Globus

Resource Management Application Resource Broker ? Types of resources needed ? Local Resource Manager Service/Resource Resource Co-allocator Resource Information Manager Query job  Specifications of requests Multi-request request Service/Resource

Open Grid Services Architecture (OGSA) Global Grid Forum ( driving force behind OGSAwww.gridforum.org Promoting a standard and open architecture for interfaces to resources Assuring proper uniform behavior of all resources and interoperability in a heterogeneous environment

The Grid Service Implemented as special a Web service Standardized behavior  Standardized interfaces Standard interfaces in terms of Web Services Description Language (WSDL)  GSDL Implementation independent The grid service is able to live on any host environment that supports web services. Examples: J2EE,.NET, C, Python, … which cover most existing operating systems

The Grid Service Interface Grid Services must support: Discovery Registry: holds information about service instances Dynamic Service (instance) creation Factory: creates service instances Lifetime management Life length, termination of service in case of failure of resource Notification Manageability Monitoring and managing service instances Grid Services can also provide (custom) application services, like web services

How does a Grid Service work? Client uses a Grid service interface A grid service instance is created from a Factory with the help of a Registry The grid service instances run with appropriate resources automatically allocated New instances can allocated and destroyed dynamically, to benefit performance Example: A web serving environment could dynamically allocate extra instances to provide consistent user response time

Simple Invocation Example User Invocation Real Services -EJB -Java Class Factory Service Instance … Compute service provider Database Service DB n Database Service DB 1 … … Service Instance Registry

Hierarchical Use of Grid Services Simple Hosting Environment Virtual Hosting Environment Collective Services Environment

Relationship with Middleware at large Distributed Computing Grid computing itself can be thought of as a distributed system Differs by providing a controlled, dynamic resource-sharing framework that addresses the requirements of a grid Comparison to CORBA, J2EE, and.NET Grid computing can be used as a building block in other middleware systems ‘Too much middleware’ Benefiting other middleware technologies Web services is making advances due to grid services

Conclusions Characteristics of a grid relevant to middleware Common design methodologies in grid middleware Grid Services and open standardization New and existing middleware systems are beginning to adopt core grid middleware to become easily ‘grid-enhanced’

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