Michigan Computers


The Michigan computer cluster consists of several interactive machines, and 2 condor batch queue clusters. Here is the current list of machines:

Interactive Machines

  • umt3int01, umt3int02, umt3int03.physics.lsa.umich.edu : These are dual-dual core Opteron Machines with 12 GB memory each running SLC4.
  • attera, linat01.grid.umich.edu: These are older machines running SLC4 and SLC3, respectively.

Condor Batch Queues

Michigan Computers at CERN.

  • umats1.cern.ch, umats2.cern.ch: These are servers currently located in B188-3-004. They have RAID arrays with some of our AFS space (such as the CHDATA area for chamber testing/DB area). They are behind the CERN firewall so you can only log into them from within CERN.
  • marsXX.cern.ch (XX=01-05): Machines in B513. Each has scratch area /home/public which are NFS mounted at /marsXX. They have a condor queue. Jobs may be submitted from any machine (mars01 is the scheduler).

Disks, AFS access

The cluster has both AFS and NFS mounted filesystems. The AFS cell is /afs/atlas.umich.edu. Here are some of the major filesystems:

/afs/atlas.umich.edu/atlas/software Home of ATLAS software
/afs/atlas.umich.edu/home User home directories
/afs/atlas.umich.edu/CHData Chamber commissioning data
/dataXX / NFS scratch disks XX=01, 02, .., 08. These are auto-mounted as /net/dataXX when a user accesses them (i.e. they do not show up with "df" until you access them)

To gain access to the AFS filesystems you must get kerberos tickets (Kerberos 5) and AFS tokens which you get automatically at login. Here are some commands related to these:

command function
kinit username Obtain Kerberos tickets for user username
klist List the Kerberos tickets owned by a user
kdestroy Delete the Kerberos tickets owned by a user
aklog Obtain AFS tokens
tokens List AFS tokens owned by a user
unlog Delete AFS tokens owned by a user

Note that the CERN AFS domain uses Kerberos 4 and gets tickts and tokens with command: kinit -4 username@CERN.CH


The following print queues are defined on linat01, linat06, umrocks, and umopt1:

Queue Description
ocsbw Black & white printer in Randall 2416 (OCS printer room)
ocscolor Color in Randall 2416 (OCS printer room) default printer
wh361bw Black & white printer in West Hall 361
wh361color Color printer in West Hall 361
hp2281 printer in Randall 2281 (electronics shop)

To print with these commands use commands:

lpq -P<queue> 
List jobs in queue
lpr -P<queue> <file>
Print file (text or postscript)
lprm -P<queue> <id>
Remove print job id

Printer Setup

Here are directions for installing all print queues listed above on a Michigan machine using the CUPS print server. Be aware that doing so will overwrite any existing queues. Queues can also be added (and monitored) using the Cups web interface at http://localhost:631 (you must start a web browser from the machine in question and log in with the root pw to add a queue). The cups configuration files have been put in /afs/atlas.umich.edu/atlas/software/cups_config. See also the README file in that directory. To configure Cups follow the steps below. The lines beginning with "$" are commands to be entered.

  • log on as root
  • $ cd /etc/cups this directory has cups configuration
  • you might want to examine printers.conf to see if any printers are already defined. If so, either carefully edit together the old and new printers.conf files, or add new printers using the web interface.
  • $ cp /afs/atlas.umich.edu/atlas/software/cups_config/printers.conf /etc/cups
  • $ cp /afs/atlas.umich.edu/atlas/software/cups_config/ppd/*.* /etc/cups/ppd
  • $ service cups restart
  • Note: service cups status tells you if cups is running or not. Make sure that cups is configured to always start at boot time.

-- EdwardDiehl - 28 Sep 2006
Topic revision: r24 - 16 Oct 2009, TomRockwell
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