sge_shepherd.8
NAME
sge_shepherd - Grid Engine single job-controlling agent
SYNOPSIS
sge_shepherd
DESCRIPTION
sge_shepherd provides the parent process functionality for a single
Grid Engine job. The parent functionality is necessary on UNIX systems
to retrieve resource usage information (see getrusage(2)) after a job
has finished. In addition, the sge_shepherd forwards signals to the
job, such for suspension, enabling, termination, and the Grid Engine
checkpointing signal (see sge_ckpt(5) and queue_conf(5) for details).
The sge_shepherd receives information about the job to be started from
the sge_execd(8). During the execution of the job it actually starts
up to 5 child processes. First a prolog script is run if this feature
is enabled by the prolog parameter in the cluster configuration. (See
sge_conf(5).) Next a parallel environment startup procedure is run if
the job is a parallel job. (See sge_pe(5) for more information.) After
that, the job itself is run, followed by a parallel environment
shutdown procedure for parallel jobs, and finally an epilog script if
requested by the epilog parameter in the cluster configuration. The
prolog and epilog scripts, as well as the parallel environment startup
and shutdown procedures, are to be provided by the Grid Engine
administrator and are intended for site-specific actions to be taken
before and after execution of the actual user job.
After the job has finished and the epilog script is processed,
sge_shepherd retrieves resource usage statistics about the job, places
them in a job-specific subdirectory of the sge_execd(8) spool directory
for reporting through sge_execd(8), and finishes.
sge_shepherd also places an exit status file in the spool directory.
This exit status can be viewed with qacct -j JobId (see qacct(1)); it
is not the exit status of sge_shepherd itself but of one of the methods
executed by sge_shepherd. This exit status can have several meanings,
depending on the method in which an error occurred (if any). The
possible methods are: prolog, parallel start, job, parallel stop,
epilog, suspend, restart, terminate, clean, migrate, and checkpoint.
The following exit values are returned:
0 All methods: Operation was executed successfully.
99 Job script, prolog and epilog: When FORBID_RESCHEDULE is not set
in the configuration (see sge_conf(5)), the job gets re-queued.
Otherwise see "Other".
100 Job script, prolog and epilog: When FORBID_APPERROR is not set
in the configuration (see sge_conf(5)), the job gets re-queued.
Otherwise see "Other".
Other Job script: This is the exit status of the job itself. No action
is taken upon this exit status because the meaning of this exit
status is not known.
Prolog, epilog and parallel start: The queue is set to error
state and the job is re-queued.
Parallel stop: The queue is set to error state, but the job is
not re-queued. It is assumed that the job itself ran
successfully and only the clean up script failed.
Suspend, restart, terminate, clean, and migrate: Always
successful.
Checkpoint: Success, except for kernel checkpointing: checkpoint
was not successful, did not happen (but migration will happen).
For the meaning of the return codes of the shepherd itself (which are
interpreted by qacct(1)) see sge_status(5).
RESTRICTIONS
sge_shepherd should not be invoked manually, but only by sge_execd(8).
ENVIRONMENT VARIABLES
SGE_ROOT Specifies the location of the Grid Engine standard
configuration files.
SGE_CELL If set, specifies the default Grid Engine cell. To
address a Grid Engine cell sge_execd uses (in the order
of precedence):
The name of the cell specified in the environment
variable SGE_CELL, if it is set.
The name of the default cell, i.e. default.
SGE_ENABLE_COREDUMP
If set, enable core dumps on Linux when the admin_user
is not root. Linux normally disables core dumps when
the daemon has changed uid or gid. Setting
SGE_ENABLE_COREDUMP in sge_execd's environment defeats
that to enable core dumps for debugging if they are
otherwise allowed. This is typically not a big hazard
with SGE, since most information is exposed in the spool
area anyhow. Dumps will appear in the qmaster spool
directory, which need not be world-readable.
On Solaris, coreadm(1) may be used to enable such dumps.
SGE_CGROUP_DIR If Linux cgroups handling is enabled, this variable
names a directory under the cgroup mount point in which
to create job-specific directories. The default is
sge.SGE_CELL so, for instance, the cpuset cgroup for a
job might be /sys/fs/cgroup/cpuset/sge.default/123.
FILES
sgepasswd contains a list of user names and their corresponding
encrypted passwords. If available, the password file will be used by
sge_shepherd. To change the contents of this file please use the
sgepasswd command. It is not advised to change that file manually.
<execd_spool>/job_dir/<job_id> job specific directory
<sge_root>/<cell>/common/sgepasswd
Password information used on Microsoft Windows hosts. See
sgepasswd(5).
SEE ALSO
sge_intro(1), sge_conf(5), sge_status(5), remote_startup(5),
sgepasswd(5), sge_execd(8).
COPYRIGHT
See sge_intro(1) for a full statement of rights and permissions.
SGE 8.1.3pre $Date: 2007-07-19 09:04:33 $ SGE_SHEPHERD(8)
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