How to access, set up, and test your account

Preliminary steps

All the documentation is maintained in the T3 twiki pages: https://wiki.chipp.ch/twiki/bin/view/CmsTier3/WebHome . Please take a look at it to explore T3's capabilities.

Information about T3 mailing-lists:

  • Subscribe to the cms-tier3-users list using this web interface (list archives): cms-tier3-users@lists.psi.ch. This mailing-list is used to communicate information on Tier-3 matters (downtimes, outages, news, etc.) or for discussions among users and admins.
  • To privately contact the CMS Tier-3 administrators, write to: cms-tier3@lists.psi.ch
  • NOTE: Both lists are read by the administrators and are archived. You can submit support requests to either of them. Mails to the user list have the added advantage that they can be read by everyone.

Please also take a look at our policies about usages, quotas, etc.. Tier3Policies.

T3 Linux Groups

All the T3 users are partitioned in several primary groups and the users also belong to the secondary group cms that's used for common files like the CMS files uploaded at T3 by PhEDEx:
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 Linux Groups:

  • allow a faster and simpler understanding of the /pnfs space usage by leveraging on the gid setting.
  • allow to make accounting in the Sun Grid Engine batch system also according to the gid setting.
  • made possible the creation of the "group dirs" /pnfs/psi.ch/cms/trivcat/store/t3groups/ where just the group members can write or delete.
  • simplify the /shome, /pnfs, /scratch and /tmp space usage accounting.

Following an ETHZ user with his primary and his secondary group:

$ id auser
uid=571(auser) gid=532(ethz-higgs) groups=532(ethz-higgs),500(cms)
Following the users 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
...
Following the "group dirs" /pnfs/psi.ch/cms/trivcat/store/t3groups/ ; since they're "group dirs" there is not a real owner so they belong to the root user and the group has the w permission:
 $ 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

Basic setup

We offer the following SL6 user interfaces ( UIs ) :

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 a t3ui1* machine 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 graphical applications
    ssh -Y username@t3ui12.psi.ch
    
  2. If you are an external user and you don't have a standard PSI account, you'll have to change your initial password the first time you log in; use the standard passwd utility.
  3. Copy your grid credentials to the standard places, i.e. to ~/.globus/userkey.pem and ~/.globus/usercert.pem and make sure that their files permissions are set correctly:
    -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 files from your CERN User Grid-Certificate 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. You have to complete the CMS "Virtual Organization" subscription or the following command voms-proxy-init -voms cms won't work. CERN details about that, e.g. who is your representative.
  6. Create a proxy certificate for CMS by:
    voms-proxy-init -voms cms
    
    If that fails, run the command with an additional -debug flag, and the error message will usually be sufficient for the T3 Admins to point out the problem.
  7. Test your access to the PSI Storage element with the test-dCacheProtocols command. You should see an output like this (without any failed test):
    $ test-dCacheProtocols
    Test directory: /tmp/dcachetest-20150115-1328-23031
    TEST: GFTP-write ......  [OK]
    TEST: GFTP-ls ......  [OK]
    TEST: GFTP-read ......  [OK]
    TEST: DCAP-read ......  [OK]
    TEST: SRMv2-write ......  [OK]
    TEST: SRMv2-ls ......  [OK]
    TEST: SRMv2-read ......  [OK]
    TEST: SRMv2-rm ......  [OK]
    
  8. Be aware of the external CSCS CMS User Page
  9. The test-dCacheProtocols tool can also be used to test a remote storage element (use the -h flag to get more info about it): e.g. to test the CSCS storage element:
    $ test-dCacheProtocols -n storage01.lcg.cscs.ch -p /pnfs/lcg.cscs.ch/cms/trivcat/store/user/YOUR_CMS_ACCOUNT -i "DCAP-read"
    Test directory: /tmp/dcachetest-20150115-1333-23178
    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]
    

It's possible to get changed your login shell, e.g. from bash to tcsh, your group, also your account name ; often users requested to change their Grid cert subject:, e.g. because they were moving from a country to an other where they got a new certificate.

Getting an AFS CERN Ticket

In order to access the CERN /afs protected dirs ( e.g. your home ) :
kinit ${Your_CERN_Username}@CERN.CH
aklog cern.ch
The first command gives you a kerberos ticket, the second command uses that ticket to obtain an authentication token from CERN's AFS service

t3ui1* SSH pub keys

Hackers on Internet are constantly waiting for user mistakes, even just a misspelled letter like in this example:
$ 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 .ch with a .sh so pay attention to these cases ! To avoid to digit the T3 hostnames you might define these permanent aliases instead :
More... Close
$ grep alias ~/.bash_profile | grep t3ui
alias ui12='ssh -X at3user@t3ui12.psi.ch'
alias ui15='ssh -X at3user@t3ui15.psi.ch'
alias ui16='ssh -X at3user@t3ui16.psi.ch'
alias ui17='ssh -X at3user@t3ui17.psi.ch'
alias ui18='ssh -X at3user@t3ui18.psi.ch'
alias ui19='ssh -X at3user@t3ui19.psi.ch'


More subdole attacks are the SSH man in the middle attacks ; to detect them you have to register in /$HOME/.ssh/known_hosts each t3ui1* SSH RSA public key by running these steps on each laptop/desktop/server ( also lxplus ! ) that you're going use to login at T3:
cp -p /$HOME/.ssh/known_hosts /$HOME/.ssh/known_hosts.`date +"%d-%m-%Y"`
mkdir /tmp/t3ssh/
for X in 19 18 17 16 15 12 ; do TMPFILE=`mktemp /tmp/t3ssh/XXXXXX` && ssh-keyscan -t rsa  t3ui$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 12 15 16 17 18 19 ; do echo -n "# entries for t3ui$X = " ; grep -c t3ui$X /$HOME/.ssh/known_hosts  ; grep -Hn --color t3ui$X /$HOME/.ssh/known_hosts ; echo ;  done
echo done
last for reports if there are duplicated rows in /$HOME/.ssh/known_hosts for a t3ui1* server ; if there are you're suppose to preserve the correct occurrence and delete the others ; to delete you can use sed -i or by hands by vim or emacs ; once you'll get just one row per t3ui1* server run this command and carefully compare your output with this output:
More... Close
$ ssh-keygen -l -f /$HOME/.ssh/known_hosts | grep t3ui 
2048 d0:9c:a0:e9:8f:9c:3f:b2:f1:88:6c:15:32:07:fc:a0 t3ui12.psi.ch,t3ui12,192.33.123.132 (RSA)
2048 77:1b:27:5e:c8:74:64:86:f8:50:f6:58:e6:6f:41:65 t3ui15.psi.ch,t3ui15,192.33.123.135 (RSA)
2048 35:bb:d6:be:64:86:8d:db:1d:57:43:ef:05:39:72:c8 t3ui16.psi.ch,t3ui16,192.33.123.136 (RSA)
2048 27:d1:57:f0:ac:da:1d:db:54:11:5c:46:4d:93:63:59 t3ui17.psi.ch,t3ui17,192.33.123.137 (RSA)
2048 b1:56:06:5b:d3:da:1a:79:60:e9:02:16:be:82:fe:f7 t3ui18.psi.ch,t3ui18,192.33.123.138 (RSA)
2048 73:fe:97:b2:e7:54:df:99:50:dc:19:3d:6f:cd:01:11 t3ui19.psi.ch,t3ui19,192.33.123.139 (RSA)


force your ssh client to always check if the server you're connecting to is already mentioned in the /$HOME/.ssh/known_hosts file and to request your consensus for servers that are absent by adding this line in /$HOME/.ssh/config :
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 t3ui1* SSH RSA public and private keys will be never changed, so the case It is also possible that the RSA host key has just been changed will be never true.

CERN CA files

Install and 'trust' any CERN CA file in the browser where is loaded your X509 Digital Certificate ( that probably you got from CERN as well )
https://cafiles.cern.ch/cafiles/

VOMS Group /cms/chcms NEW

It has been created a VOMS Group /cms/chcms to better serve the Swiss community of LHC physicist ; all the Swiss CMS users should require the VOMS Group /cms/chcms membership in order to automatically get :
  • higher priority in the CSCS ( T2_CH_CSCS in CMS terms ) batch queues
  • additional Jobs slots in the CSCS batch queues
  • additional /pnfs space in the CSCS grid storage
  • in the future, better protection of the file transfers at T3 vs the CMS file transfers coming from Internet

Once the /cms/chcms membership will be granted from each UI in the CMS Grid, like the T3 UIs t3ui1* but also from the lxplus servers at CERN, by running the usual voms-proxy-init --voms cms command a Swiss user will automatically get the /cms/chcms attribute ; that can be verified by running :

$ voms-proxy-info --all | grep /cms
attribute : /cms/Role=NULL/Capability=NULL
attribute : /cms/chcms/Role=NULL/Capability=NULL
So with your Digital Certificate ( X509 ) properly loaded in your Web Browser click on https://voms2.cern.ch:8443/voms/cms/group/edit.action?groupId=5 and require the /cms/chcms membership ; be aware of that port :8443, your Institute network policies might prevent the outgoing traffic vs that port ; if that's the case then escalate the problem to your Institute network team or simply require the /cms/chcms membership from another less constrained network ( like from your DSL at home )

T3 Admins Skype Accounts NEW

Both to help the T3 users with their T3/T2 errors or misunderstandings and to interactively support their next 'what if ?' T3/T2 plans there is a Skype account fabio.martinelli_2 to video talk or simply chat with the T3 Admins ; we invite the T3 users to install Skype, create an account and add fabio.martinelli_2 as a contact.

For ordinary cases the cms-tier3@lists.psi.ch remains the 1st mean to require our support.

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Topic revision: r39 - 2015-04-28 - FabioMartinelli
 
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