Basic aliensh S. Bagnasco, INFN Torino CNAF Nov 27-28, 2007

Preparing the certificates Certificates should be stored under $HOME/.globus Globus enforces privacy on your private key! (chmod 400)

Changes in environment . /tmp/gclien_env_…

Getting a GRID proxy Authentication command (default is the local username) Happens every 24 hours Put certificate password

Getting an AliEn token

Authentication problems I Globus related: Permissions on $HOME/.globus/userkey.pem are not private to the user chmod 400 userkey.pem Your certificate authority is exotic and not known to the server. Your certificate has expired. Clock skew: Your local computer time is in the future with respect to the server's time. Your local computer time is more in the past than the certificate life time.

Authentication problems II alien-token-init related: You have not gone through all 5 steps of the AliEn user registration. You have not given the AliEn user name as an argument to the token-init command and your local user name is not identical to the AliEn user name. The script wants to bootstrap the installation but you don’t have write permissions on the installation path Avoid bootstrapping by setting the GSHELL_ROOT environment variable. API servers are not working…

Try it out! Upload your certificates to your machines: Store them under e.g: /afs/cern.ch/user/t/trn2301/.globus/ Check that the key file is read only. Get a valid alien token. If asked if you want to compile the gapi and xrootd libs answer YES (everything is already precompiled)

Accessing the shell Message of the day. Standard bash shell with grid comands Main bash features are available. Not all shell helper programs are available. Some local commands (like ls, cat etc) are overwritten with the corresponding GRID commands. File/path tab completion in the virtual GRID directory. Message of the day.

Tab completion working!!! Shell Basic commands I Tab completion working!!!

Shell Basic commands II

Shell Basic commands III

whereis command

Viewing files I

viewing files II

Editing files Define your preferred editor via the variable EDITOR: 'emacs' 'emacs -nw' 'xemacs' 'xemacs -nw' 'pico' 'vi' (DEFAULT) 'vim' The file is temporary in /tmp on your local disk and then is uploaded once you exit the editor!

Clean up old versions

Copying out files GOLDEN RULE If you want to access your local directory structure while you are in the shell you should start by having the prefix “file:” e.g: cp file:/home/pchrist/gshell.sh gshell.sh

File catalogue structure The path name will be: for ‘real’ data: /data/<Year>/<AcceleratorPeriod>/<RunNumber>/ for simulated data: /sim/<Year>/<ProductionType>/<RunNumber>/ Subdirectories will be called: Raw/ cond/ reco/<PassX>/ESD/ reco/<PassX>/AOD/ … File names will look like this: <xxxx>.AliESD.root For further information see: http://indico.cern.ch/conferenceDisplay.py?confId=3280 http://cern.ch/Oldenburg/MetaData/MetaData.doc

Querying the File Catalogue aliensh:[alice] [1] find -x pp /alice/cern.ch/user/p/pchrist/Tutorial/PDC06/* *Merged*tag.root > pp.xml Redirect the output to the xml collection.

Querying the File catalogue aliensh:[alice] [1] find -x pp /alice/data/2008/LHC08a/*/reco/Pass3/* *Merged*tag.root Run:collision_system=”pp” and Run:stop<"2008-03-20 10:20:33" and Run:start>"2008-03-19" > pp.xml

Try it out I Access the alien shell and try some simple commands: Check your user name by typing ‘whoami’. List the contents of your home directory. Print the working directory. Create the following directory structure in your AliEn space: $HOME/bin (if it is not there) $HOME/GridSchool Get the information of the file with ‘whereis’: /alice/cern.ch/user/s/sbagnasc/GridSchool/GridSchoolNov2007.tgz Check $HOME

Try it out II Try the -v option! Copy the AliEn file /alice/cern.ch/user/s/sbagnasc/GridSchool/GridTutorial-November2007.tgz to your local $HOME/GridSchool Exit the shell and unpack the file locally by typing: tar xvzf GridSchoolNov2007.tgz Enter again the shell and register: The .csh files in your AliEn $HOME/bin The .jdl files in your AliEn $HOME/GridSchool Try the -v option!

Try it out iII Play with the ‘find’ command: Access the shell again and query the f.c. and get all the tag files (*.tag.root) under: /alice/sim/2007/LHC07c/pp_minbias/8268/* Get the output on your terminal (find /alice/…) Get the output on your terminal in a xml format (find -x tag /alice/…) Redirect the results to the tag.xml collection: the output will not be stored in your AliEn working directory but rather in your local working directory. Repeat the previous exercise limiting the number of output files to 5 (find -l 5 ...).

Tomorrow Whatever is left over from today… Write a JDL to generate some file Submit the job and check its progress Check the job’s output Write a JDL to look at the output Submit it to run wherever the file is Get the result If there is some time left, do the same actually generating MC events and reconstructing them, or even analyzing some PDC data…