Introduction to Grids By: Fetahi Z. Wuhib [CSD2004-Team19]

Definition  A grid is a software framework providing layers of services to access and manage distributed hardware and software resources  Owned by different organizations  Resource location immaterial as long as connected through a computer network  Grid computing aims at creating a simple, large, powerful and self managing virtual computer from Virtual Organizations  A Virtual Organization [VO] is a group of people or institutions with some common purpose or interest that want to share and use resources  Common sharing rules

What are the resources?  Computation power: run applications on the grid  Requires an application to be split into separate parts to run on different processors  Storage  Primary/Secondary storage  Striping/mirroring/replica’s  Communication links  Software/application and/or licenses  Special equipment  etc

Internet Vs Grid  Just as the World Wide Web allows people to share content via Internet protocols, grid computing---allows widely dispersed organizations to share resources

Grid software components  Management software  Keep track of resources and users  Donor software  Running on machines contributing resources  Submission software  Used to submit “jobs”  Schedules  Assign “jobs” to resources

Requirements for a Grid  A grid should allow a highly controlled, direct access “sharing” relationship between any potential participants  Interoperability is a key issue  Protocols  Standard services made available over the protocols  Applications should be developed so that they will be able to run over the “grid”  SDK/API

Grid Architecture  Layered architecture  Protocols at each layer build on the capabilities of lower layers  Architecture neck at collective/Resource layer  Minimal set of protocols allow many high level apps

Fabric  Interface to local control  Provides resources to which access is mediated by the grid protocols  Implements local operations that occur as a result of higher layer applications  Include computational resources, storage systems, applications, network resources, etc  Employ “local” protocols to achieve desired operation  If “local” protocol lacks required functionality, this layer fills in the gap.

Connectivity  Define core communication/authentication protocols  Communication protocols are used to exchange data between fabric layer resources  Include transport, routing and naming protocols  Currently protocols form the TCP/IP stack are used [IP/TCP/UDP/DNS/OSPF]

…connectivity  Authentication protocol should support  Single sign on  Delegation  Interoperability with existing protocols  User based trust  Existing authentication protocols don’t support the above listed characteristics  A new protocol that extends over existing authentication protocols is required

Resource  Sharing a single resource through underlying communication protocols  Two major classes  Information protocols: state of the resource, e.g. load, cost  Management protocols: negotiate access to a resource  Forms the neck of the grid architecture: should define a small and focused sets that capture the fundamental sharing mechanisms

Collective  Coordinating multiple resources unlike the underlying layer  Interactions across multiple resources  Domain minimized from general to highly application specific  E.g.  Directory Services used to display existence /availability of resources  Monitoring and diagnostics services support monitoring of VO resources for failures, overload, congestion, intrusion, etc

Applications  User applications that operate within a VO environment  Constructed by calling upon services defined at any of the lower layers

The Globus Toolkit  Open source software toolkit used for building grids  Developed by the Globus Alliance  addresses issues of security, information discovery, resource management, data management, communication, fault detection, and portability

…the Globus Toolkit  Based on the GSI (Grid Security Infrastructure)  Three major components  Resource management [GRAM]  Information services [MDS]  Data management [GridFTP]

What next??  Globus server bundle installation successful  Study the 3 major components of Globus  Give special focus on GridFTP  P2P file sharing??  Study the possibility of implementing this interface

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