, Prague JAN ŠVEC Institute of Physics AS CR

 History and main users  Hardware description  Networking  Software and jobs distribution  Management  Monitoring  User support

 HEP LHC - ATLAS, ALICE Tevatron - D0 RHIC - Star H1, Calice  Astrophysics Auger  Solid State Physics  Others (HEP section of Institute of Physics)  Active participation in GRID projects since 2001 (EDG, EGEE, EGEE II, EGEE III (running), EGI) in collaboration with CESNET Czech Tier-2 site, connected to 2 Tier-1 sites (Forschungszentrum Karlsruhe – Germany, ASGC – Taiwan) and 3 Tier-3 sites (MFF Troja, FJFI ČVUT, ÚJF Řež, ÚJF Bulovka, UTEF)

 first computers bought in 2001 (2 racks), placed in the main building insufficient cooling, small space, small UPS, inconvenient access (2nd floor)  new server room opened in 2004  server room and adjacent office  18 racks  200kVA UPS  350kVA diesel  2 cooling units  water cooling planned for 2009  automatic fire suppression system (Argonite gas)  good access

 35x dual PIII 1.13 GHz  67x dual Xeon 3.06 GHz  5x dual Xeon 2.8 GHz Redundant components Key services  3x dual Opteron 1.6 GHz File servers  36x bl35p - dual Opteron 275, 280  6x bl20p - dual Xeon 5160  8x bl460 - dual Xeon 5160  12x bl465 - dual Opteron 2220

 HP Netserver TB SCSI  Easy Stor - 10TB ATA  Easy Stor - 30TB SATA  Promise Vtrak M610p - 13TB SATA  HP EVA TB FATA (SATA over FC)  Overland Ultramus - 144TB SATA DPM pool  Overland Ultramus 12TB Fiber Channell 4Gb tape library cache  100 TB tape library - LTO4 (expandable to 400TB)

 SGI Altix ICE 8200  512 cores, Intel Xeon 2.5 GHz  1GB RAM per core  Diskless nodes  External SAS disk array 7.2 TB  Infiniband 4x (20 Gbps)  Suse Linux Enterprise Server  Torque + Maui  SGI ProPack

 IBM iDataPlex  672 cores, Intel Xeon 2.83 GHz  2GB RAM per core  local SAS disks 300GB  Scientific Linux Cern 4  Torque + Maui  First in Europe

 Scientific Linux (Cern) 4, 5  Suse Linux (SLES 10, Opensuse 11)  32bit, 64bit testing in progress  Job management - PBSPro 9.x, Torque with Maui scheduler fair share used for scheduling cputime and walltime multiplicators  Legato Networker - tape backup (user homes, configuration)  gLite grid middleware (CE, SE, UI, MON box, site BDII, …)  Job submission Local – “prak” interface (grid unsupported experiments) ○ No special requirements GRID - UI interface (Atlas, Alice, Auger) ○ X509 certificate, signed by GRID certification authority (Cesnet, CERN)  Interface hosts merging in progress

 installation using PXE + kickstart  system automatically updates from SLC repositories  gLite middleware configured with YAIM (integrated into cfengine  local site changes managed using cfengine

 Manual administration is tedious and error prone Configuration is scattered among several places ○ Kickstart’s postinstall vs. existing nodes Ad-hoc changes, no revisions ○ Communication among sysadmins Machines temporarily offline ○ Conflicting changes Issues when reinstalling ○ Stuff went missing Too much work  Cfengine to the rescue! Managing hundreds of boxes from a central place Change tracking with subversion Describe the end result, not the process

 Cfengine architecture a central server running cfservd ○ Server policy files and other data to nodes cfagent on each node ○ Performs the real changes cfexecd (cron) ○ A thin wrapper around cfagent  configuration at one place can be easily managed by SCMs  shooting yourself in the foot easily any change can have huge impact - think before doing changes ! interactions among rules might have unexpected results => TESTING IS IMPORTANT!

 Flexible monitoring is crucial for reliability  Nagios, Munin (graphic representation of time development of events), PBS graphs, MRTG, CEF monitoring, …  Why Nagios de facto standard in monitoring open source easy to write new sensors static configuration is not a problem lots of addons ○ Nuvola – better look for nagios ○ NagiosReport (developed locally, summarizes problems at site) ○ NagiosGrapher (generates graphs from nagios outputs) ○ …  Plugins default plugins (part of nagios installation) - ping, disk, procs, load, swap, ldap, … SRCE plugins (developed by E. Imamagic) - cert, dpm, gridftp, srm, … locally developed – hpacucli, ups, jobs, gstat

Nagios summary generated at 11/28/ :10:02 in seconds. ====================================================================== Hosts in trouble: golias123, golias131 Hosts in downtime (not monitored): golias01, golias02, golias38 ====================================================================== golias123: ========== CFAGENT: CHECK_NRPE: Socket timeout after 30 seconds. golias131: ========== CFAGENT: CHECK_NRPE: Socket timeout after 30 seconds. downtimes: ========== golias01: Down for tests of cfengine installation. golias02: Down for golias02-golias199 synchronization tests. golias38: Disk failure.

 User support  Mailing list (primarily used for news, announcements of downtimes,  wiki pages with documentation (user and admin sections)  RT (Request Tracking) system developed by Best Practical Solutions – operated by Cesnet in cooperation with FZU used by users for communication with administrators 1. user sends mail to 2. RT system creates ticket with unique number 3. all administrators are notified by RT, that new ticket was created 4. administrators can communicate the problem with user (using reply function) or with each other (using comment function). All communication is saved as part of the ticket 5. each week RT automatically reminds administrators of all opened tickets