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LCG Computing Element (lcg CE)

  • Functional description
    • LCG CE is a native computing resource access service with Globus Gatekeeper. LCG has modified some of its component to improve its performance like job manager.
  • Daemons running
    • globus-gatekeeper - must be started
    • globus-gridftp - must be started
    • globus-job-manager-marshal - must be started
    • globus-gass-cache-marshal - should be started, but the client is able to work in fall-back mode with stopped daemon
    • globus-gma - must be started if GLOBUS_GMA is enabled in site's config
  • Init scripts and options (start|stop|restart|reload|...)
    • globus-job-manager-marshal, globus-gass-cache-marshal and globus-gma scripts support 'reload' action to send a SIGHUP to a daemon.
  • Configuration files location with example or template
    • /opt/globus/etc/globus-gass-cache-marshal.conf, /opt/globus/etc/globus-job-manager-marshal.conf
    • logf (srting) - location of the log file (default is relative to GLOBUS_LOCATION)
    • maxproc (numeric) - maximum number of parallel requests [this is the most useful variable for tuning] (5 by default)
    • rrobin (numeric) - enables round-robin queue mode for users(1) or groups (2) (disabled (0) by default)
    • tick (numeric) - hung child processes are killed every this number of seconds (if no other events are happening) (300 by default).
    • reqtout (numeric) - client should send a complete request in this number of seconds after connection (10 by default)
    • proctout (numeric) - each request (child process) is allowed to run this number of seconds (600 by default)
    • reqlimit (numeric) - maximum size of a request in bytes (16384 by default). One should increase this limit if environment is very large.
    • window (numeric) - data block for recv/send in bytes, probably should never be changed (default value is 4096 (x86 page size)).
    • debug (numeric) - debug level. There are three of them: 0 - only warnings (default), 1 - all messages, 2 - stderr is being redirected to the log file (bad for log parsers, but good for catching problems in perl jobmanagers)
    • All parameters (except debug 1 -> 2) could be changed online (modify config file and sent a sighup), both daemons create pidfiles in /var/run/ but their location is not configurable.

  • Logfile locations (and management) and other useful audit information
    • /opt/globus/var/log/*.log - configurable with logf option above.
    • /var/log/globus-gridftp.log
    • /var/log/globus-gatekeeper.log
    • /var/log/message
    • /opt/edg/var/gatekeeper/
  • Possible unit test of the service
    • Submitting jobs to it through both WMS and globus-job-run
  • Where is service state held (and can it be rebuilt)
    • Under home directory of pool account
  • Cron jobs
    • The cron jobs can be found in /etc/cron.d/ and are:
      • bdii-proxy
      • edg-mkgridmap
      • lcg-expiregridmapdir
      • cleanup-grid-accounts
      • edg-pbs-knownhosts
      • cleanup-job-records
      • edg-pbs-shostsequiv
      • edg-apel-pbs-parser
      • fetch-crl
  • Utility scripts
  • Location of reference documentation for users
  • Location of reference documentation for administrators
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Topic revision: r4 - 2008-09-03 - DiQing
 
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