# Getting started with FCC distributed computing :::{admonition} Page contributors :class: callout dropdown Gerardo Ganis, Juraj Smiesko, Brieuc Francois ::: For more detailed documentation how user's can use the distributed resources managed by iLCDirac, refer to the iLCDirac's [User Guide](https://ilcdirac-doc.web.cern.ch/DOC/Files/UserGuide/index.html). ## Registering to the FCC VO The [standard Grid VO registration procedure][signup] should be followed to be able to use the resources connected with the FCC Virtual Organization (VO). If your request is pending approval for too long, please [contact us](mailto:FCC-PED-SoftwareAndComputing-Coordination@cern.ch). :::{admonition} Note :class: callout As for the VO registration, you need to use a browser where you can import your GRID certificate together with the [CERN CA][cernca] certificates. Firefox usually works fine, Google Chrome usually does not work. Safari might also work. ::: ## Enabling DIRAC DIRAC is available on CernVM-FS. To enable the relevant applications and scripts, the following setup script needs first to be sourced ```bash source /cvmfs/clicdp.cern.ch/DIRAC/bashrc ``` To submit jobs through DIRAC a proxy needs to be created and uploaded: ```bash dirac-proxy-init -g fcc_user ``` A successful creation looks like this: ``` Generating proxy... Enter Certificate password: Added VOMS attribute /fcc Uploading proxy.. Proxy generated: subject : /DC=ch/DC=cern/OU=Organic Units/OU=Users/CN=ganis/CN=393971/CN=Gerardo Ganis/CN=2178341058/CN=3000266373 issuer : /DC=ch/DC=cern/OU=Organic Units/OU=Users/CN=ganis/CN=393971/CN=Gerardo Ganis/CN=2178341058 identity : /DC=ch/DC=cern/OU=Organic Units/OU=Users/CN=ganis/CN=393971/CN=Gerardo Ganis timeleft : 23:53:58 DIRAC group : fcc_user path : /tmp/x509up_u2759 username : ganis properties : NormalUser VOMS : True VOMS fqan : ['/fcc'] Proxies uploaded: DN | Group | Until (GMT) /DC=ch/DC=cern/OU=Organic Units/OU=Users/CN=ganis/CN=393971/CN=Gerardo Ganis | | 2022/05/13 12:12 ``` The last section shows the valid proxies upload to the DIRAC system. It can also be checked with ```bash dirac-proxy-info -m ``` with output similar to ``` subject : /DC=ch/DC=cern/OU=Organic Units/OU=Users/CN=ganis/CN=393971/CN=Gerardo Ganis/CN=2178341058/CN=3000266373 issuer : /DC=ch/DC=cern/OU=Organic Units/OU=Users/CN=ganis/CN=393971/CN=Gerardo Ganis/CN=2178341058 identity : /DC=ch/DC=cern/OU=Organic Units/OU=Users/CN=ganis/CN=393971/CN=Gerardo Ganis timeleft : 23:50:40 DIRAC group : fcc_user path : /tmp/x509up_u2759 username : ganis properties : NormalUser VOMS : True VOMS fqan : ['/fcc'] == Proxies uploaded == DN | Group | Until (GMT) /DC=ch/DC=cern/OU=Organic Units/OU=Users/CN=ganis/CN=393971/CN=Gerardo Ganis | | 2022/05/13 12:12 ``` If everything worked fine, your proxy should be mapped to the `fcc001` user. This can be checked this way: ```bash export EOS_MGM_URL=root://eospublic.cern.ch XrdSecPROTOCOL=gsi,unix eos whoami ``` the result should look similar to this: ``` Virtual Identity: uid=140035 (99,140035) gid=2855 (99,2855) [authz:gsi] host=lxplus743.cern.ch domain=cern.ch geo-location=0513 ``` At CERN the uid of `fcc001` is `140035`. ## Copying, browsing, accessing files Once DIRAC is enabled it is possible to copy, browse and access files. For the example we used the file `edm4hep_test_output.root` . Files can be copied in the area of each user with, for example, `xrdcp`: ``` xrdcp edm4hep_test_output.root root://eospublic.cern.ch//eos/experiment/fcc/user/g/ganis/edm4hep_test_output.root [5B/5B][100%][==================================================][5B/s] ``` The immediate availability of the file can be checked with ``` $ xrdfs eospublic.cern.ch ls /eos/experiment/fcc/prod/fcc/user/g/ganis /eos/experiment/fcc/prod/fcc/user/g/ganis/edm4hep_test_output.root ``` or, `/eos` is mounted, with ``` $ ls -lt /eos/experiment/fcc/prod/fcc/user/g/ganis total 9545 -rw-r--r--. 1 fcc001 fcc-cg 9768981 Nov 3 2021 edm4hep_test_output.root ``` Files can be replicated to another Storage Element, e.g. CNAF-DISK, using `dirac-dms-replicate-lfn`: ``` $ dirac-dms-replicate-lfn /fcc/user/g/ganis/edm4hep_test_output.root CNAF-DISK ``` The availability of the files can be browsed using the command `dirac-dms-lfn-replicas`: ``` $ dirac-dms-lfn-replicas /fcc/user/g/ganis/edm4hep_test_output.root LFN StorageElement URL ============================================================= /fcc/user/g/ganis/edm4hep_test_output.root CNAF-DISK davs://xfer-archive.cr.cnaf.infn.it:8443/fcc/user/g/ganis/edm4hep_test_output.root CERN-DST-EOS gsiftp://eospublicftp.cern.ch//eos/experiment/fcc/prod/fcc/user/g/ganis/edm4hep_test_output.root ``` The file can be accessed through the indicate path; for example: ``` $ source /cvmfs/sw.hsf.org/key4hep/setup.sh $ root -l root [0] TFile *f1 = TFile::Open(“davs://xfer-archive.cr.cnaf.infn.it:8443/fcc/user/g/ganis/edm4hep_test_output.root”) (TFile *) 0x2ec28b0 root [1] ``` ## The web portal The [DIRAC web portal][diracweb] is available to check the status of things. It shows all the jobs submitted and the files registered. An example screenshot is shown below. ![ILCDirac Web](images/dirac-web-job-listing.png) [signup]: https://fcc-auth.cern.ch/start-registration [diracweb]: https://voilcdiracwebapp2.cern.ch/DIRAC/?theme=Classic&url_state=1|*DIRAC.JobMonitor.classes.JobMonitor:, [cernca]: https://ca.cern.ch/cafiles/certificates/Grid.aspx