How to access, set up, and test your account

Compulsory Initial Setups

All the documentation is maintained in the T3 twiki pages: https://wiki.chipp.ch/twiki/bin/view/CmsTier3/WebHome . Please bookmark it and explore the T3's capabilities.

Information about the two T3 mailing-lists:

• Subscribe to the cms-tier3-users@lists.psi.ch mailing list using its web interface (list archives): this mailing list is used to communicate information on Tier-3 matters (downtimes, outages, news, upgrades, etc.) or for discussions among users and admins.
• To privately contact the CMS Tier-3 administrators write to cms-tier3@lists.psi.ch instead ; no subscription is needed for this mailing list.
• Both lists are read by the administrators and are archived. You can submit support requests to either of them but emails addressed to the cms-tier3-users@lists.psi.ch are read by everyone so they could get answered better and sooner, especially if you ask about specific CMS software ( CRAB3, CMSSW, Xrootd, ... )

T3 policies

Read and respect the Tier3Policies

Linux groups

Each T3 user belongs to both a primary group and a common secondary group cms, the former is meant to classify common files like the ones downloaded by the PhEDEx file transfer service ; the T3 primary groups are :

ETHZ	UniZ	PSI
ethz-ecal	uniz-higgs	psi-bphys
ethz-bphys	uniz-pixel	psi-pixel
ethz-ewk	uniz-bphys
ethz-higgs
ethz-susy

The T3 primary groups allow :

• an easier /pnfs /shome /scratch /tmp space monitoring
• an easier batch system monitoring
• to protect the /pnfs group files because only the group members will be able to delete those files ; very often that's NOT guaranteed by the others CMS T1/T2/T3 !
• to manage the groups areas /pnfs/psi.ch/cms/trivcat/store/t3groups/ ; in a such dir each new file belongs to root and to a specific T3 group, it doesn't matter which specific T3 user uploads the files ( but clearly he/she's a group member )

For instance this is the primary and the secondary group of a generic T3 account :

$ id auser
uid=571(auser) gid=532(ethz-higgs) groups=532(ethz-higgs),500(cms)

The following output is a fragment of the private user dirs /pnfs/psi.ch/cms/trivcat/store/user/ :

$ ls -l /pnfs/psi.ch/cms/trivcat/store/user | grep -v cms 
total 56
drwxr-xr-x    2 alschmid     uniz-bphys 512 Feb 21  2013 alschmid
drwxr-xr-x    5 amarini      ethz-ewk   512 Nov  7 15:37 amarini
drwxr-xr-x    2 arizzi       ethz-bphys 512 Sep 16 17:49 arizzi
drwxr-xr-x    5 bean         psi-bphys  512 Aug 24  2010 bean
drwxr-xr-x    5 bianchi      ethz-higgs 512 Sep  9 09:40 bianchi
drwxr-xr-x   98 buchmann     ethz-susy  512 Nov  5 20:36 buchmann
...

The T3 groups areas /pnfs/psi.ch/cms/trivcat/store/t3groups/ :

 $ ls -l /pnfs/psi.ch/cms/trivcat/store/t3groups/
total 5
drwxrwxr-x 2 root ethz-bphys 512 Nov  8 15:18 ethz-bphys
drwxrwxr-x 2 root ethz-ecal  512 Nov  8 15:18 ethz-ecal
drwxrwxr-x 2 root ethz-ewk   512 Nov  8 15:18 ethz-ewk
drwxrwxr-x 2 root ethz-higgs 512 Nov  8 15:18 ethz-higgs
drwxrwxr-x 2 root ethz-susy  512 Nov  8 15:18 ethz-susy
drwxrwxr-x 2 root psi-bphys  512 Nov  8 15:18 psi-bphys
drwxrwxr-x 2 root psi-pixel  512 Nov  8 15:18 psi-pixel
drwxrwxr-x 2 root uniz-bphys 512 Nov  8 15:18 uniz-bphys
drwxrwxr-x 2 root uniz-higgs 512 Nov  8 15:18 uniz-higgs
drwxrwxr-x 2 root uniz-pixel 512 Nov  8 15:18 uniz-pixel

User Interfaces ( UI )

Three identical User Interfaces ( UIs ) servers are available to their specific users to both develop their programs and to send their computational jobs to the T3 batch system by the qsub command :

Access to Login nodes is based on the institution

The access is not restricted to allow for some freedom, but you are requested to use the UI dedicated to your institution.

UI Login node	for institution	HW specs
t3ui01.psi.ch	ETHZ, PSI	132GB RAM , 72 CPUs core (HT), 5TB /scratch
t3ui02.psi.ch	All	132GB RAM , 72 CPUs core (HT), 5TB /scratch
t3ui03.psi.ch	UNIZ	132GB RAM , 72 CPUs core (HT), 5TB /scratch

1. Login into your t3ui0* server by ssh ; use -Y or -X flag for working with X applications; you might also try to connect by NX client, which allows to work efficiently with your graphical applications

   ssh -Y username@t3ui02.psi.ch
   

2. If you are an external PSI user ( ETHZ, UniZ, ... ) modify the initial password sent you the first time you'll connect to your UI; use the standard passwd tool.
3. Copy your grid credentials to their standard places, i.e. to ~/.globus/userkey.pem and ~/.globus/usercert.pem and make sure that their permissions are properly set, like :

   -rw-r--r--  1 feichtinger cms 2961 Mar 17  2008 usercert.pem
   -r--------  1 feichtinger cms 1917 Mar 17  2008 userkey.pem
   

   For details about how to extract those .pem files from your CERN User Grid-Certificate ( usually a password protected .p12 file )please read https://gridca.cern.ch/gridca/Help/?kbid=024010.
4. Source the grid environment associated to your login shell:

   source /swshare/psit3/etc/profile.d/cms_ui_env.sh   # for bash
   source /swshare/psit3/etc/profile.d/cms_ui_env.csh  # for tcsh
   

5. ( Optional ) Modify your shell init files in order to automatically load the grid environment ; for BASH that means placing :

   [ `echo $HOSTNAME | grep t3ui` ] && [ -r /swshare/psit3/etc/profile.d/cms_ui_env.sh ] && source /swshare/psit3/etc/profile.d/cms_ui_env.sh && echo "UI features enabled" 

   into your ~/.bash_profile file.
6. Run env|sort and verify that /swshare/psit3/etc/profile.d/cms_ui_env.{sh,csh} has properly activated the setting

   X509_USER_PROXY=/shome/$(id -un)/.x509up_u$(id -u)"

   ; that setting is crucial to access a CMS Grid SE from your T3 jobs.
7. You must register to the CMS "Virtual Organization" service or the following command voms-proxy-init -voms cms won't work. CERN details about that, e.g. who is your representative.
8. Create a proxy certificate for CMS by:

   voms-proxy-init -voms cms
   

   If the command voms-proxy-init -voms cms will fail then run the command with an additional -debug flag, the error message will be usually sufficient for the T3 Admins to troubleshoot the problem.
   
9. Test your access to the PSI Storage element by the test-dCacheProtocols command ; you should get an output like this (possibly without any failed test) ; sometime the XROOTD-WAN-* tests might get stuck due to the I/O traffic coming from Internet but as a local T3 user you're actually supposed to use the XROOTD-LAN I/O door that is unaccessible from Internet, so you might skip the XROOTD-WAN-* tests by either simply pressing Ctrl-C or by passing the option : -i "XROOTD-LAN-write" ( see below )

   $ test-dCacheProtocols
   Test directory: /tmp/dcachetest-20150529-1449-14476
   TEST: GFTP-write ......  [OK]   <-- vs gsiftp://t3se01.psi.ch:2811/
   TEST: GFTP-ls ......  [OK]
   TEST: GFTP-read ......  [OK]
   TEST: DCAP-read ......  [OK]   <-- vs dcap://t3se01.psi.ch:22125/
   TEST: SRMv2-write ......  [OK]   <-- vs srm://t3se01.psi.ch:8443/
   TEST: SRMv2-ls ......  [OK]
   TEST: SRMv2-read ......  [OK]
   TEST: SRMv2-rm ......  [OK]
   TEST: XROOTD-LAN-write ......  [OK]   <-- vs root://t3dcachedb03.psi.ch:1094/ <-- Use this if you run LOCAL jobs at T3 and you need root:// access to the T3 files
   TEST: XROOTD-LAN-ls ......  [OK]
   TEST: XROOTD-LAN-read ......  [OK]
   TEST: XROOTD-LAN-rm ......  [OK]
   TEST: XROOTD-WAN-write ......  [OK]   <-- vs root://t3se01.psi.ch:1094/ <-- Use this if you run REMOTE jobs and you need root:// access to the T3 files ; e.g. you're working on lxplus
   TEST: XROOTD-WAN-ls ......  [OK]
   TEST: XROOTD-WAN-read ......  [OK]
   TEST: XROOTD-WAN-rm ......  [OK]
   

1. The test-dCacheProtocols tool can be also addressed vs a remote storage element (use the -h flag to get more info about it) but it's important to avoid all the LAN tests ( -i "DCAP-read XROOTD-LAN-write XROOTD-WAN-write" ) ; e.g. to check the CSCS storage element storage01.lcg.cscs.ch :

   $ test-dCacheProtocols -s storage01.lcg.cscs.ch -x storage01.lcg.cscs.ch -p /pnfs/lcg.cscs.ch/cms/trivcat/store/user/martinel -i "DCAP-read XROOTD-LAN-write XROOTD-WAN-write"
   Test directory: /tmp/dcachetest-20150529-1545-16302
   TEST: GFTP-write ......  [OK]
   TEST: GFTP-ls ......  [OK]
   TEST: GFTP-read ......  [OK]
   TEST: DCAP-read ......  [IGNORE]
   TEST: SRMv2-write ......  [OK]
   TEST: SRMv2-ls ......  [OK]
   TEST: SRMv2-read ......  [OK]
   TEST: SRMv2-rm ......  [OK]
   TEST: XROOTD-LAN-write ......  [IGNORE]
   TEST: XROOTD-LAN-ls ......  [SKIPPED] (dependencies did not run:  XROOTD-LAN-write)
   TEST: XROOTD-LAN-read ......  [SKIPPED] (dependencies did not run:  XROOTD-LAN-write)
   TEST: XROOTD-LAN-rm ......  [SKIPPED] (dependencies did not run:  XROOTD-LAN-write)
   TEST: XROOTD-WAN-write ......  [IGNORE]
   TEST: XROOTD-WAN-ls ......  [SKIPPED] (dependencies did not run:  XROOTD-WAN-write)
   TEST: XROOTD-WAN-read ......  [SKIPPED] (dependencies did not run:  XROOTD-WAN-write)
   TEST: XROOTD-WAN-rm ......  [SKIPPED] (dependencies did not run:  XROOTD-WAN-write)
   

Backup policies

Your /shome files are backuped :

• each day

recovering a file is as simple as running a cp command from your UI ; further details are here HowToRetrieveBackupFiles.

There are NO backups all the /tmp /scratch /pnfs files instead, so pay attention there !

Optional Initial Setups

Installing the CERN CA files into your Web Browser

Install in your Web Browser any CERN CA file, conversely your Web Browser might constantly bother you about all the CERN https:// URLs ; typically the Web Browsers feature many well known CA files by default but not the CERN CA files.

Applying for the VOMS Group /cms/chcms membership

It's available a dedicated 'Swiss' VOMS Group called /cms/chcms in order to get more rights over the CMS HW resources installed at T2_CH_CSCS, Lugano ; namely :

• higher priority on the T2_CH_CSCS batch queues
• additional Jobs slots on the T2_CH_CSCS batch queues
• additional /pnfs space inside the T2_CH_CSCS grid storage
• during 2017, a group area like the T3 groups areas /pnfs/psi.ch/cms/trivcat/store/t3groups/

When a user belongs to the /cms/chcms group, and he runs voms-proxy-init --voms cms, the voms-proxy-info --all will report the new /cms/chcms/Role=NULL/Capability=NULL attribute, like :

$ voms-proxy-info --all | grep /cms
attribute : /cms/Role=NULL/Capability=NULL
attribute : /cms/chcms/Role=NULL/Capability=NULL

To apply for the /cms/chcms membership load your X509 into your daily Web Browser ( probably your X509 is already there ), then click on https://voms2.cern.ch:8443/voms/cms/group/edit.action?groupId=5 and request the /cms/chcms membership ; be aware that the port :8443 might be blocked by your Institute Firewall, if that's the case contact your Firewall team or simply try from another network ( like your net at home )

Saving the UIs SSH pub host keys

Hackers are constantly waiting for a user mistake, even a simple misspelled letter like in this case occurred in 2015 :

$ ssh t3ui02.psi.sh
The authenticity of host 't3ui02.psi.sh (62.210.217.195)' can't be established.
RSA key fingerprint is c0:c5:af:36:4b:2d:1f:88:0d:f3:9c:08:cc:87:df:42.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 't3ui02.psi.sh,62.210.217.195' (RSA) to the list of known hosts.
at3user@t3ui02.psi.sh's password:

The T3 Admins can't prevent a T3 user from confusing a .ch with a .sh so pay attention to these cases ! To avoid mistaking the T3 hostnames you can define the following aliases in your shell :

$ grep alias ~/.bash_profile | grep t3ui
alias ui01="ssh -X $USER@t3ui01.psi.ch"
alias ui02="ssh -X $USER@t3ui02.psi.ch"
alias ui03="ssh -X $USER@t3ui03.psi.ch"

Another hackers attack is the SSH man in the middle attack ; to prevent it proactively save in /$HOME/.ssh/known_hosts each t3ui0* SSH RSA public key by running these commands on each of your daily laptop/PC/server ( also on lxplus ! ) :

cp -p /$HOME/.ssh/known_hosts /$HOME/.ssh/known_hosts.`date +"%d-%m-%Y"`
mkdir /tmp/t3ssh/
for X in 01 02 03 ; do TMPFILE=`mktemp /tmp/t3ssh/XXXXXX` && ssh-keyscan -t rsa  t3ui$X.psi.ch,t3ui$X,`host t3ui$X.psi.ch| awk '{ print $4}'` | cat - /$HOME/.ssh/known_hosts | grep -v 'psi\.sh'  > $TMPFILE && mv $TMPFILE /$HOME/.ssh/known_hosts ; done
rm -rf /tmp/t3ssh
for X in 01 02 03 ; do echo -n "# entries for t3ui$X = " ; grep -c t3ui$X /$HOME/.ssh/known_hosts  ; grep -Hn --color t3ui$X /$HOME/.ssh/known_hosts ; echo ;  done
echo done

the last for reports if there are duplicated rows in /$HOME/.ssh/known_hosts for a t3ui0* server ; and if there are then you've to preserve the correct occurrence and delete the others ; to delete you can either use sed -i or an editor like vim / emacs / nano / nedit ; once you'll get just one row per t3ui0* server run this command and carefully compare your output with this output:

$ ssh-keygen -l -f /$HOME/.ssh/known_hosts | grep t3ui 
2048 SHA256:0Z8Su5R4aZthbePGMM14mEKxYFOuKyrnUe9GjU0m6vM t3ui01.psi.ch,192.33.123.23 (RSA)
2048 SHA256:2qA9YDNeOEbGYjIdpRdBJpywQDne5gRbRvN/myL5P8o t3ui02.psi.ch,192.33.123.29 (RSA)
2048 SHA256:SoIL0H0ueyASNkyYID3a16AIHuAEP7AQ5iaQ6vrvzfk t3ui03.psi.ch,192.33.123.85 (RSA)

modify your client /$HOME/.ssh/config in order to force the ssh command to always check if the server you're connecting to is already reported in the /$HOME/.ssh/known_hosts file and to ask for your 'OK' for all the servers that are missing :

StrictHostKeychecking ask

your /$HOME/.ssh/config can be more complex than just that line, study the ssh_config man page or contact the T3 Admins; ideally you should put StrictHostKeychecking yes but in real life that's impractical.

now your ssh client will be able to detect the SSH man in the middle attacks and if so it will report :

  WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! 
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY! 
Someone could be eavesdropping on you right now (man-in-the-middle attack)! 
It is also possible that the RSA host key has just been changed.

The t3ui0* SSH RSA public/private keys will never change, so the case It is also possible that the RSA host key has just been changed will actually never occurs.

Creating an AFS CERN Ticket

To access the CERN /afs protected dirs ( e.g. your CERN home on AFS ) you'll need to create a ticket from CERN AFS :

kinit ${Your_CERN_Username}@CERN.CH
aklog cern.ch

The first command will provide you a Kerberos ticket while the second command will use the Kerberos ticket to obtain an authentication token from CERN's AFS service

The T3 Admins Skype Accounts

The Skype accounts are no longer the suggested way of contacting the T3 admins.

Web browsing your /shome files on demand

We don't provide a http{s}:// URL to browse your /shome logs/errors/programs because there was always a modest interest about a such web portal but you can turn on a private website rooted on an arbitrary dir of yours by simply using SSH + Python like in the following example ( replace t3ui02 with your daily t3ui server and the dir with a dir meaningful for your case, for instance ~ ):

ssh -L 8000:t3ui02.psi.ch:8000 t3user@t3ui02.psi.ch "killall python ; cd /mnt/t3nfs01/data01/shome/ytakahas/work/TauTau/SFrameAnalysis/Scripts/ && python -m SimpleHTTPServer"

open your Web browser to the page http://localhost:8000/ . That's it.

the preliminary killall python; command is meant to kill a previous python -m SimpleHTTPServer run that might be still active but if you've other python programs they will be also killed ; in that case delete the initial killall python; command and kill a previous python -m SimpleHTTPServer command by :

t3ui02 $ kill -9 `pgrep -f "^python -m SimpleHTTPServer*"`

if some other T3 user is already using the t3ui02.psi.ch:8000 TCP port then use another port like 8001, 8002, etc.. :

ssh -L 8000:t3ui02.psi.ch:8001 t3user@t3ui02.psi.ch "killall python ; cd /mnt/t3nfs01/data01/shome/ytakahas/work/TauTau/SFrameAnalysis/Scripts/ && python -m SimpleHTTPServer 8001"