Gonçalo Borges, Mário David, Jorge Gomes Grid Computing Back to basics: the concept, the model, the infrastructure… EGEE & Int.EU.Grid Tutorial Lisbon, 12th Decemberr 2007 Gonçalo Borges, Mário David, Jorge Gomes LIP Lisboa

1. Concepts and Definitions goncalo@lip.pt Grid Computing – Grid Tutorial 2

What is the GRID? GRID computing is a recent concept which takes distributing computing a step forward The name GRID is chosen by analogy with the electric power grid: Transparent: plug-in to obtain computing power without worrying where it comes from Permanent and available everywhere The World Wide Web provides seamless access to information that is stored in many millions of different geographical locations In contrast, the GRID is a new computing infrastructure which provides seamless access to computing power and data storage distributed all over the globe goncalo@lip.pt Grid Computing – Grid Tutorial 3

GRID vs Distributed Computing Distributed infrastructures already exist, but… they normally tend to be local & specialized systems: Intended for a single purpose or user group Restricted to a limit number of users Do not allow coherent interactions with resources from other institutions The GRID goes further and takes into account: Different kinds of resources: Not always the same hardware, data, applications and admin. policies Different kinds of interactions: User groups or applications want to interact with Grids in different ways Access computing power / storage capacity across different administrative domains by an unlimited set of non-local users Dynamic nature: Resources added/removed/changed frequently World wide dimension goncalo@lip.pt Grid Computing – Grid Tutorial 4

The GRID Metaphor The transparent interaction between heterogeneous resources (owned by geographically spread organizations), applications and users is only possible through… the use of a specialized layer of software called middleware G R I D M L E W A Visualising Workstation Mobile Access The middleware hides the infrastructure technical details and allows a secure integration/sharing of resources. Internet protocols do not provide security mechanisms for resource sharing. goncalo@lip.pt Grid Computing – Grid Tutorial 8

2. How to access to the GRID? goncalo@lip.pt Grid Computing – Grid Tutorial 10

User & Administrator Perspectives Users need single sign-on: the ability to logon to a machine and have the user’s identity passed to other resources as required to trust owners of the resources they are using Providers of resources (computers, databases,..) need to trust users they do not know minimise impact on security have the ability to trace who did what The solution comes from Digital Certificates Virtual Organizations goncalo@lip.pt Grid Computing – Grid Tutorial 11

X.509 Public Key Infrastructure Digital Certificates Resource providers are “opening themselves up” to itinerant users: A Secure Access to resources is provided through the X.509 Public Key Infrastructure Digital certificates identify uniquely its user/service identity Users/Services identity have to be certified by (mutually recognized) national Certification Authorities (CAs) One CA per country CAs are coordinated by global bodies to enable the creation of a world-wide trust zone (EUGridPMA) Digital certificates allow a temporary delegation from users to processes executed “in user’s name” (proxy certificates and myproxy certificates repositories) goncalo@lip.pt Grid Computing – Grid Tutorial 12

Virtualization & Sharing Virtual Organizations (VO): People from different organizations but with common goals get together to solve their problems in a cooperative way. Virtualized shared computing resources: VO members have access to computing resources outside their home institutions. Virtualized shared data resources: VOs members can store and access data outside their home institutions. Other resources may be shared and virtualized as well: Instruments, sensors, software and even people… VO practical role: Set Common Agreed Policies for accessing resources Administrates the VO membership list Before joining a VO, a person must already have a valid certificate VO administrators can reject persons which do not fulfill the VO requirements goncalo@lip.pt Grid Computing – Grid Tutorial 13

Particle Physics Comunity VOs Examples Particle Physics Comunity Biomed Comunity High Energy Comunity Cancer Research Comunity goncalo@lip.pt Grid Computing – Grid Tutorial 14