CRAB @ FNAL Tutorial 12 October 2007

Introduction

The CRAB @ FNAL tutorial is a hands-on introduction to distributed user analysis within the CMS computing model. The user will learn about the CMS computing model and the user GRID analysis tool CRAB. All information will be presented in the form of short talks and hands-on exercises. The goal of this tutorial is to prepare all participants to use and succeed in using the GRID for their analyses.

Prerequisites / Requirements

Copied to CRABatFNALPrerequisites

All participants are advised to start early with the registration processes each step can take a few days to be processed.

• A UAF/LPC account at Fermilab: Please follow http://www.uscms.org/SoftwareComputing/UserComputing/GetAccountFermilab.html
• A personal laptop able to login to CMSUAF/CMSLPC at FNAL and open X windows: Please follow http://www.uscms.org/SoftwareComputing/UserComputing/ConnectUAF.html
• GRID credentials (certificate and CMS registration): Please follow https://twiki.cern.ch/twiki/bin/view/Main/CRABPrerequisitesGRIDCredentials and complete all described steps
  • A valid GRID certificate is the most important prerequisite for this tutorial. Without it, users cannot participate successfully.

GRID Certificate Verification

To guarantee successful participation, a valid GRID certificate is needed. Each user has to successfully execute two commands on the cmsuaf/cmslpc before attending the tutorial.

• Execute the generation of a GRID certificate proxy with:

  voms-proxy-init -voms cms
  

• Check the validity of the generated proxy with the following command:

  voms-proxy-info -all
  

  which should produce output similar to:

  subject   : /DC=org/DC=doegrids/OU=People/CN=Your Name 123456/CN=proxy
  issuer    : /DC=org/DC=doegrids/OU=People/CN=Your Name 123456
  identity  : /DC=org/DC=doegrids/OU=People/CN=Your Name 123456
  type      : proxy
  strength  : 512 bits
  path      : /tmp/x509up_u12840
  timeleft  : 11:59:54
  VO        : cms
  subject   : /DC=org/DC=doegrids/OU=People/CN=Your Name 123456
  issuer    : /C=CH/O=CERN/OU=GRID/CN=host/lcg-voms.cern.ch
  attribute : /cms/Role=NULL/Capability=NULL
  attribute : /cms/uscms/Role=NULL/Capability=NULL
  timeleft  : 11:59:54
  

  If one of the above steps fails, please follow https://twiki.cern.ch/twiki/bin/view/Main/CRABPrerequisitesGRIDCredentials and complete all described steps. If you need additional assistance, contact Eric Vaandering (ewv@fnalNOSPAMPLEASE.gov).

The Tutorial

We'll begin with a short talk and then follow hands on steps which will show you how to submit CRAB jobs and give you some idea of the flexibility of CRAB

Additional resources

A number of talks and tutorials from the June 2007 workshop may be quite useful. This was a full day tutorial, so it was much more comprehensive.

• Introduction to the CMS computing model (Ian Fisk) CMS_CM_CRAB_Tut.pdf
• Introduction to data discovery and DBS (Valentin Kuznetsov) DBS2_discovery_FNAL.pdf
• DashBoard and Monitoring (Ian Fisk) https://twiki.cern.ch/twiki/bin/view/CMS/WorkBookMonitoringTutorial
• Hands-on session to submit CRAB jobs CRAB tutorial for ≥ CMSSW_1_5_X or CRAB tutorial for ≤ CMSSW_1_4_X
• CRAB debugging techniques 070627_crab_debugging.pdf
• Support Channels (Patrick Gartung) supportchannels_jun07.ppt