sge_commd

SGE_COMMD(8)Grid Engine Enterprise Edition Administrative CommandsSGE_COMMD(8)



NAME
       sge_commd - Grid Engine Enterprise Edition communication agent

SYNOPSIS
       sge_commd [ -S ] [ -a aliasfile ] [ -dhr ] [ -help ] [ -ll loglevel ] [
       -ml fname ] [ -nd ] [ -p port ] [ -s service ]

DESCRIPTION
       All network communication in a Grid Engine Enterprise Edition cluster
       is performed via the communication daemons sge_commd. Client programs
       like qsub(1) or qstat(1) as well as Grid Engine Enterprise Edition
       daemons such as sge_qmaster(8) or sge_execd(8) use the service provided
       by sge_commd in order to send/receive messages to/from other Grid
       Engine Enterprise Edition components.

       sge_commd handles an arbitrary number of concurrent synchronous or
       asynchronous communications. Usually one sge_commd is started up
       automatically on each host on which sge_qmaster(8), sge_execd(8) or/and
       sge_schedd(8) are invoked. It is however possible to connect multiple
       hosts via one sge_commd or to use a sge_commd on a submit or
       administrative Grid Engine Enterprise Edition host (without running one
       of the other Grid Engine Enterprise Edition daemons) as communication
       agent for the Grid Engine Enterprise Edition client programs invoked
       from that host.

OPTIONS
       -S     Forces secure ports to be used for communication between
              sge_commds and between other Grid Engine Enterprise Edition
              components and the sge_commds. This requires all Grid Engine
              Enterprise Edition daemons to be started with root permission
              and the client programs to be configured set-uid root. In turn,
              it ensures that unauthorized communication is prohibited for
              non-root accounts.

       -a aliasfile
              A file containing Grid Engine Enterprise Edition host aliases
              used by the sge_commd to resolve Grid Engine Enterprise Edition
              unique hostnames for all hosts in the cluster. Overrides the
              usage of the default host_aliases file under
              <sge_root>/<cell>/common/host_aliases.  The hostname resolving
              service of sge_commd is also used by all other Grid Engine
              Enterprise Edition components.  The file format and the
              implication of its usage are described in sge_h_aliases(5).

       -dhr   The hostname resolving C-library functions (such as
              gethostent(3), gethostbyname(3) and gethostbyaddr(3)) perform
              some kind of caching on some OS architectures.  Network wide
              hostname databases distributed by services such as DNS (Domain
              Name Service) and NIS (Network Information Service) are updated
              with a delay of several minutes. This only affects applications
              which repeatedly resolve hostnames (such as sge_commd). At
              start-up of a program the most recent information is accessed,
              thus commands like telnet(1) or nslookup(1) are not affected.
              However, for sge_commd it makes no sense to resolve hostnames
              anytime (the returned information may be out of date anyway) and
              resolving can be an expensive operation if the network is
              overloaded and/or NIS or DNS servers are very busy. Therefore,
              sge_commd resolves hostname information from time to time only.
              Yet, if hostname resolving still causes problems due to network
              load, for example, it can be turned off with the -dhr switch.
              The administrator has to be aware, that if the hostname
              resolving is turned off, sge_commd has to be restarted as soon
              as the hostname databases change significantly.

       -help  Prints  a listing of all options.

       -ll loglevel
              Sets a logging level for error tracing. The error trace
              information is written to the file /tmp/commd/err.<pid>.
              However, the directory /tmp/commd must be present, otherwise the
              tracing output is discarded. At present, 255 is the only valid
              logging level.

       -ml fname
              Enables message logging to file.

       -nd    Do not daemonize. If started with -nd, sge_commd maintains its
              connection to the controlling terminal and thus outputs trace
              information directly to the terminal from which sge_commd was
              invoked. The trace information is the same as being accessible
              via the -ll option (see above).

       -p port_number
              Use this TCP port for communication with other commds.

       -s service_name
              Use this service name and thus the associated TCP port for
              communication with other commds.

ENVIRONMENTAL VARIABLES
       SGE_ROOT       Specifies the location of the Grid Engine Enterprise
                      Edition standard configuration files.

       COMMD_PORT     If set, specifies the tcp port on which sge_commd is
                      expected to listen for communication requests.  Most
                      installations will use a services map entry instead to
                      define that port.

       COMMD_HOST     (Does not affect the behavior of sge_commd but of the
                      other Grid Engine Enterprise Edition components
                      contacting sge_commd.)  If set, specifies the host on
                      which the particular sge_commd to be used for Grid
                      Engine Enterprise Edition communication of arbitrary
                      Grid Engine Enterprise Edition client programs or
                      daemons resides. Per default the local host is used.

RESTRICTIONS
       sge_commd usually is invoked by a starting sge_qmaster(8) and
       sge_execd(8) and thus is running under root permission.  If started by
       a normal user the -S switch may not be used as the secure mode requires
       root permission (see above).

SEE ALSO
       sge_intro(1), sge_h_aliases(5), sge_execd(8), sge_qmaster(8),
       commdcntl(8).

COPYRIGHT
       See sge_intro(1) for a full statement of rights and permissions.



GEEE 5.3                 $Date: 2002/01/25 14:04:55 $             SGE_COMMD(8)