CHEP 2009

Something you may have wanted to know about L&B

26 Mar 2009, 08:00

1h

Prague

Board: Thursday 060

poster Grid Middleware and Networking Technologies Poster session

Speakers

Mr Ales Krenek (CESNET, CZECH REPUBLIC)Mr Jiri Sitera (CESNET, CZECH REPUBLIC)Mr Ludek Matyska (CESNET, CZECH REPUBLIC)Mr Miroslav Ruda (CESNET, CZECH REPUBLIC)Mr Zdenek Sustr (CESNET, CZECH REPUBLIC)

Description

Logging and Bookkeeping (L&B) is a gLite subsystem responsible for tracking jobs on the grid. Normally the user interacts with it via glite-wms-job-status and glite-wms-job-logging-info commands. Here we present other, less generally known but still useful L&B usage patterns which are available with recently developed L&B features. L&B exposes a HTML interface; pointing a web browser (after having loaded grid credentials into it) to a jobid displays the job status details on a simple web page. Similarly, the L&B server endpoint URL shows a clickable list of active user's jobs and notification handles. Corresponding plain-text interface is available by appending `?text' modifier to jobid or the server endpoint, yielding the same data in a predictable key=value form suitable for parsing in scripts. Making job status info available via RSS feeds is planned in near future. Apart of actively querying L&B server users can also subscribe for receiving notifications on job state changes. Possible criteria range from simple `whatever happens to this job' to `job of this VO user gets resubmitted to another CE'. Notifications are accessed via both API and CLI (suitable for scripting). Information gathered by L&B can witness on reputability of computing elements, namely detect apparent `black holes' where jobs are accepted quickly, and they fail immediately. This information can be leveraged in JDL rank expression via specific ClassAd function to penalize such misbehaving CEs in job matching.

Presentation materials

Poster

poster_LB_Features.pdf