Grid Status 2 0 Enabling Grids for Escienc

Grid Status 2. 0 Enabling Grids for E-scienc. E Overview GStat Validation The Grid Information System is a mission-critical component of the EGEE production infrastructure. It enables users, applications and services to discover which services exist and further information about their structure and state. It is therefore important that the information system components themselves are functioning correctly and that the information content is reliable. Grid Status (GStat) is the monitoring component of the EGEE information system, a hierarchical system built out of more than 260 site level and 70 global aggregation services. It validates the information which is presented and provides summary and history displays for use by Grid operators and system administrators. Version 2. 0, a major revision of GStat, is currently in the final stages of development. The GStat validation package contains a set of scripts that are used to validate an information source. These scripts use a common library to ensure that they all have the same "look and feel" and behave in a consistent manner. This source for the tests can either be an LDAP server or an LDIF file. The results of testing can be directed to different output channels; the two main ones being standard out and the GStat database. GStat Monitoring Architecture The GStat architecture is split into four main areas: core, validation, monitoring and visualization. At the centre of the system is a database where the data model defines the interface between the other areas. GStat core is responsible for extracting information from the information system and maintaining an entity cache. GStat visualization uses this information for the structure of displays and GStat validation conducts various validation tests on the information content. This mechanism has been designed so that it can be also be executed on the command line and as such can be used directly by system administrators and automated testing suites. GStat monitoring uses the entity cache to configure a monitoring framework that leverages Nagios. The results of the validation tests are stored in the GStat database, Nagios is used for the monitoring results. GStat visualization uses all this information to present various views based on different used cases. GStat Monitoring leverages the Nagios monitoring framework and Nagios probes have been created to monitor the information system components. These probes are common to GStat and the Nagiosbased Multi-Level Monitoring Framework from the Operations Automation Team. GStat uses the entity cache to discover which information system components should be monitored by Nagios. GStat Visualization The GStat visualization package contains a visualization library and various cgi scripts that are used to produce the web pages. The pages present the information from the GStat database and Nagios. Custom pages can be created using the visualization library. GStat Core The GStat core package contains common libraries and scripts that are used by the other components. The primary function of this package is to initialize and maintain the GStat database. A snapshot of the information system is stored in the database and can be used to find metadata about the sites and services. This snapshot is created by running the snapshot script which also updates the entity cache. EGEE-III INFSO-RI-222667 Authors: Joanna Huang and Min Tsai, ASGC L. Field, CERN-IT http: //goc. grid. sinica. edu. tw/gstat