Working with AliEn

1
Working with AliEn

• Kilian Schwarz
• ALICE Group Meeting
• April 19 2006

2
Initialisation and login

• . /u/aliprod/bin/.alienlogin
• alien proxy-init
• alien-token-init
• aliensh

3
Searching technique for simulated data with
certain properties

• Not possible with PDC01-05-data ?
• ? wait for PDC06 ?
• Current method
• aliensh
• alien find /alice/cern.ch/demo/data .root gt
  /tmp/collection.xml
• The XML collection file can be read directly by
  ROOT
• DC data can be found, e.g. in alien//alice/cern.c
  h/user/a/aliprod/production_2005/

4
Large scale data simulation using Grid

• Example at alien//alice/cern.ch/demo/production/f
  low.jdl
• Needed configuration files can be found in
  alien//alice/cern.ch/demo/production/configs
  (e.g. Config.C, rec.C, sim.C, simrun.C,)
• Start production with aliengt submit flow.jdl 001
  (run number, is used as SEED for random generator
  to be able to repeat simulation with same random
  generator initialisation)
• If you want to modify, create your own jdl and
  configuration files, following the given examples.

5
The production JDL

• our executable
• Executable aliroot (compulsary !!!)
• Has to be in alien//bin, /alice/bin or
  HOME/bin. aliroot exists already in /alice/bin
  and is a shell script executing AliRoot.
• this are pseudo names to identify the
  production
• JobtagcommentPDC05 flow events,
  round2005, tagv4-03-04, typeFlow
• the packages we need
• PackagesAliRootv4-03-04,GEANT3v1-3
• Jobs runs only at sites where those packages are
  installed
• the estimated maximal runtime in seconds
• TTL 86400 WN has to provide the requested
  run time
• this script runs when the job is finished. If
  it returns 0, the job is validated (SAVED?DONE),
  if it returns !0, the job ends in status ERROR_V
• Validationcommand /alice/cern.ch/demo/productio
  n/scripts/validation.sh

6
The production JDL 2

• this uses only sites, which are member in this
  particular grid partition
• Requirements member(other.GridPartitions,Produc
  tion)
• this are the input files/macros we need
• InputFile LF/alice/cern.ch/demo/production/con
  figs/Config.C, LF/alice/cern.ch/demo/production
  /configs/simrun.C, LF/alice/cern.ch/demo/produc
  tion/configs/sim.C, LF/alice/cern.ch/demo/produ
  ction/configs/rec.C, LF/alice/cern.ch/demo/prod
  uction/configs/CheckESD.C
• These files will be transported to the node where
  the job will run and can bei either lfn or pfn
• we want to pack the output together into
  archive files. One with all the root files, one
  with all the log files.
• OutputArchive root_archive.zipgalice.root,Kine
  matics.root,AliESDs.root_at_AliceCERNCastor2,
• log_archive.log,stdout,
  stderr_at_AliceCERNse01

7
The production JDL 3

• we define the arguments for the simulation
  script as run number and event number
• Splitargumentsimrun.C run 1 event
  alien_counter
• Arguments field for each job. Here the subjobs
  counter produced by the Split tag below is
  given. If more than one value is defined, each
  subjob will be submitted as many times as there
  are items in the array, and the subjobs will have
  the element in the array as arguments.
• we produce event number 1-10, the runnumber is
  given as argument 1 during the submission
• Split production1-10
• The job can be splitted in several sub jobs,
  according to file (1 job per input data file),
  directory (all input files of 1 directory will be
  analysed in 1 job), event (all files with the
  same name of the last subdirectory in 1 job),
  production start-ltend (no InputData required,
  it will submit the same JDL several times from
  start to finish. This counter can be referenced
  in Splitarguments using alien_counter
• Workdirectorysize1500 MB The node has to
  provide the requested size

8
Job status

• Can be investigated by using
• alien// ps
• e.g. ps f DONE (lists all finished jobs)
• ps u user (all jobs from the user)
• ps s site (all jobs on one site)
• ps trace ltjobidgt all (gives job trace
  information)
• Output can be found in alien//proc/user
• Copy output back to local via e.g.
• alien//cp output.root file/tmp/output.root