Overview of gLite
EGI combines globally-distributed computational and storage resources into a single production infrastructure available to EGI users. Each participating site configures, runs, and maintains a batch system containing its computational resources and makes those resources available to the grid via a gatekeeper.
The gLite middleware deployed on the EGI infrastructure integrates the sites’ computing resources through the Workload Management System (WMS). The WMS is a set of middleware-level services responsible for the distribution and management of jobs. The site computational resources present a common interface to the WMS, the Computing Element (CE) service.
The core of the WMS is the Workload Manager which accepts jobs from users and dispatches them to computational resources based on the users requirements on one hand, and the characteristics (hardware, software, localization) and state of the resources on the other hand. The WM is implemented as a distributed set of resource brokers, with some tens of them currently installed; all the brokers get an approximately consistent view of the resource availability through the grid information system.
The Logging and Bookkeeping service (LB) tracks jobs in terms of event(important points of job life, e.g. submission, finding a matching CE, starting execution etc.) gathered from various WMS components as well as CEs.
For more information, consult:
E. Laure et al, Programming the grid with gLite
the gLite web site