1-1.1 Introduction to Grid Computing © 2011 B. Wilkinson/Clayton Ferner. Modification date: June 20, 2011

1-1.2 “The grid virtualizes heterogeneous geographically disperse resources” from "Introduction to Grid Computing with Globus," IBM Redbooks Using geographically distributed and interconnected computers together for computing and for resource sharing. Grid Computing

1-1.3 Need to harness computers Original driving force behind Grid computing same as behind the early development of networks that became the Internet: – Connecting computers at distributed sites for high performance computing.

1a-1.4 However, Grid computing is about collaborating and resource sharing as much as it is about high performance computing.

1a-1.5 Virtual Organizations Grid computing offers potential of virtual organizations: –groups of people, both geographically and organizationally distributed, working together on a problem, sharing computers AND other resources such as databases and experimental equipment.

Different organizations can supply resources and personnel. Concept has many benefits, including: Problems that could not be solved previously for humanity because of limited computing resources can now be tackled. Examples Understanding the human genome Searching for new drugs …. Continued

Users can have access to far greater computing resources and expertise than available locally. Inter-disciplinary teams can be formed across different institutions and organizations to tackle problems that require expertise of multiple disciplines. Specialized localized experimental equipment can be accessed remotely and collectively. Large collective databases can be created to hold vast amounts of data. Unused compute cycles can be harnessed at remote sites, achieving more efficient use of computers

Crosses multiple administrative domains. Another hallmark of larger Grid computing projects. Resources being shared owned either by members of virtual organization or donated by others. Introduces challenging technical and social-political challenges. Requires true collaboration

Some key features we regard as indicative of Grid computing: –Shared multi-owner computing resources –Uses Grid computing software, with security and cross-management mechanisms in place –Tools to bring together geographically distributed computers owned by others

Shared Resources Can share much more than just computers: Storage Sensors for experiments at particular sites Application Software Databases Network capacity, …

History of distributed computing Certainly one can go back a long way to trace the history of distributed computing. Types of distributed computing existed in 1960s. Many people interested in connecting computers together for high performance computing. From connecting processors/computers together locally that began in earnest in the 1960s and 1970s, distributed computing now extends to connecting computers that are geographically distant - Grid computing

Distributed computing technologies that underpin Grid computing developed concurrently and rely upon each other. Three concurrent interrelated paths: Networks Computing platforms Software techniques

Networks 1960s - Development of packet switched networks ARPNET network became operational. 4 nodes, Univ. of California at Los Angeles, Stanford Research Institute, Univ. of California at Santa Barbara, and Univ. of Utah. Design speed of 50 Kbits/sec TCP (Transmission Control Protocol) TCP/IP (Transmission Control Protocol/Internet Protocol). TCP a protocol for reliable communication IP for network routing. IP addresses identify hosts on the Internet Ports identify end points (processes) for communication purposes. Early 1970s - Ethernet for interconnecting computers on local networks. Early 1980s - Internet. Uses the TCP/IP protocol. 1990s - Internet developed into World-Wide Web. Browser and HTML markup language introduced.

Computing Platforms 1960 onwards - Recognized that increased speed could potentially be obtained by having more than one processor inside a single computer system Parallel computer coined to describe such systems. 1970s and 1980s - many parallel computer projects especially with advent of low cost microprocessors. 1990s - cluster computing, a group of computers inter connected through a network switch to form a computing platform Commodity computers (PCs) provided cost-effective solution.

Typical cluster computing configuration Programming clusters: Message passing programming -- Messages between processes specified by programmer using message-passing routines: Late 1980s - early 1990s - PVM (Parallel Virtual Machine) Late 1990s - MPI (Message Passing Interface)

Late 1980’s onwards – Condor To harness “unused” cycles of networked computers for high performance computing. A collection of computers could be given over to remote access automatically when not being used locally. Widely used as a job scheduler for clusters in addition to its original purpose of using laboratory computers collectively. We will consider Condor in the light of Grid computing

Software Techniques Mid 1980s - Remote procedure call (RPC) for invoking a procedure on a remote computer. Service registry - introduced with RPC to locate remote services. 1990s - Object-oriented versions of RPC: CORBA (Common Request Broker Architecture) Java Method Invocation (RMI) Web service Provide remote actions as RPC but invoked through standard protocols and Internet addressing. Use XML (eXtensible Markup Language), also introduced in Web services and XML adopted into Grid computing soon after their introduction

Grid Computing History Began in mid 1990s with experiments using computers at geographically dispersed sites. Seminal experiment – “I-way” experiment at 1995 Supercomputing conference (SC’95), using 17 sites across US running: –60+ applications. –Existing networks (10 networks).

Middleware software Grid computing toolkit. Led by Ian Foster, a co-developer of I-Way demo and founder of Grid computing concept. Evolved through several versions although basic structural components remained essentially same. Globus Toolkit We will describe Globus in detail later.

Other grid computing middleware software Although Globus widely adopted and basis of our course, there are other software infrastructure projects. Europe: 1990s UNICORE (UNiform Interface to COmputing REsources) European grid computing project. Initially funded by German Ministry for Education and Research. Continued with other European funding. Basis of several European efforts and elsewhere. Many similarities to Globus. Still active EGEE, Enabling Grids for E-Science, continued as EGI, European Grid Infrastructure

gLite Lightweight Middleware for Grid Computing A framework for building grid applications part of EGEE project, continued in EMI.

Project

Key concepts in the history of Grid computing Fig. 1.2

Applications Originally e-Science applications –Computational intensive Traditional high performance computing addressing large problems Not necessarily one big problem but a problem that has to be solved repeatedly with different parameters. –Data intensive Computational but emphasis on large amounts of data to store and process –Experimental collaborative projects

Now also e-Business applications –To improve business models and practices. –Sharing corporate computing resources and databases –On-demand Grid computing … –Indirectly led to cloud computing.

Grid Computing verse Cluster Computing Important not to think of Grid computing simply as large cluster because potential and challenges different. Courses on Grid computing and on cluster computing are quite different

Cluster computing course One learns about : –Message passing programming using tools such as MPI, and –Shared memory programming using threads and OpenMP, given that most computers in a cluster today now multi-core shared memory systems. –Parallel algorithms (lots)‏ Network security is not a big issue. –Usually an ssh connection to front node of cluster sufficient. –User logging onto a single compute resource. Computers connected together locally under one administrative domain

Grid computing course Learn about running jobs of remote machines, scheduling jobs and distributed workflow Learn in detail underlying Grid infrastructure How Internet technologies applied to Grid computing Grid computing software and standards Security is an issue

Grid Computing verse Cluster Computing Of course, there are things in common Both courses hands-on with programming experiences. Both use multiple computers Both require job scheduler to place jobs

Cloud computing Lot of hype on Cloud computing at the moment. Business model in which services provided on servers that can be accessed through Internet. Lineage of cloud computing can be traced back to on-demand Grid computing in the early 2000s

Cloud computing using virtualized resources Fig. 1.3

Common thread between Grid computing and cloud computing is use of Internet to access resources. Cloud computing driven by widespread access that Internet provides and Internet technologies. However cloud computing quite distinct from original purpose of Grid computing

Grid Computing verse Cloud Computing Whereas Grid computing focuses on collaborative and distributed shared resources, Cloud computing concentrates upon placing services for users to pay to use. Technology for cloud computing emphases: – use of software as a service (SaaS)‏ – virtualization (process of separating particular user’s software environment from underlying hardware)