Ubuntu Manpage: checkpoint - Grid Engine checkpointing environment configuration file format

Provided by: gridengine-common_8.1.9+dfsg-7build1_all

NAME

       checkpoint - Grid Engine checkpointing environment configuration file format

DESCRIPTION

Checkpointing is a facility to save the complete status of an executing program or job and
to restore and restart from this so-called checkpoint at a later point of time if the
original program or job was halted, e.g. through a system crash.

Grid Engine provides various levels of checkpointing support (see sge_ckpt(1)). The
checkpointing environment described here is a means to configure the different types of
checkpointing in use for your Grid Engine cluster or parts thereof. For that purpose you
can define the operations which have to be executed in initiating a checkpoint generation,
a migration of a checkpoint to another host, or a restart of a checkpointed application.

Supporting different operating systems may easily force Grid Engine to introduce operating
system dependencies for the configuration of the checkpointing configuration file and
updates of the supported operating system versions may lead to frequently changing
implementation details. Please refer to the <sge_root>/ckpt directory for more
information.

Please use the -ackpt, -dckpt, -mckpt or -sckpt options to the qconf(1) command to
manipulate checkpointing environments from the command-line or use the corresponding
qmon(1) dialogue for X-Windows based interactive configuration.

Note, Grid Engine allows backslashes (\) be used to escape newline characters. The
backslash and the newline are replaced with a space character before any interpretation.

FORMAT

The format of a checkpoint file is defined as follows:

ckpt_name
The name of the checkpointing environment in the format for ckpt_name in sge_types(5). To
be used in the qsub(1) -ckpt switch or for the qconf(1) options mentioned above.

interface
The type of checkpointing to be used. Currently, the following types are valid:

hibernator
The Hibernator kernel level checkpointing is interfaced.

cpr The SGI kernel level checkpointing is used.

transparent
Grid Engine assumes that the jobs submitted with reference to this checkpointing
interface use a checkpointing library such as provided by the free package Condor.

userdefined
Grid Engine assumes that the jobs submitted with reference to this checkpointing
interface perform their private checkpointing method.

application-level
Uses all of the interface commands configured in the checkpointing object like in
the case of one of the kernel level checkpointing interfaces (cpr, etc.) except for
the restart_command (see below), which is not used (even if it is configured) but
the job script is invoked in case of a restart instead.

ckpt_command
A command-line type command string to be executed by Grid Engine in order to initiate a
checkpoint. The following pseudo-variables are available to be substituted in the value:

$host The name of the host on which the command is executed.

$ja_task_id
The array job task index (0 if not an array job).

$job_owner
The user name of the job owner.

$job_id
Grid Engine's unique job identification number.

$job_name
The name of the job.

$queue The cluster queue name of the master queue instance, on which the command is
started.

$job_pid
The process id of the job/task to checkpoint.

$ckpt_dir
See ckpt_dir below.

$ckpt_signal
See signal below.

$sge_cell
The SGE_CELL environment variable (useful for locating files).

$sge_root
The SGE_ROOT environment variable (useful for locating files).

migr_command
A command-line type command string to be executed by Grid Engine during a migration of a
checkpointing job from one host to another. The same pseudo-variables are available as
for ckpt_command. Note that the command is expected to create a checkpoint itself - the
checkpointing command isn't called automatically on migration.

restart_command
A command-line type command string to be executed by Grid Engine when restarting a
previously checkpointed application. The same pseudo-variables are available as for
ckpt_command.

clean_command
A command-line type command string to be executed by Grid Engine in order to cleanup after
a checkpointed application has finished. The same pseudo-variables are available as for
ckpt_command.

ckpt_dir
A file system location to which checkpoints of potentially considerable size should be
stored.

signal
A Unix signal to be sent to a job by Grid Engine to initiate checkpoint generation. The
value for this field can either be a symbolic name from the list produced by the -l option
of the kill(1) command or an integer number which must be a valid signal on the systems
used for checkpointing.

when
The points of time when checkpoints are expected to be generated. Valid values for this
parameter are composed from the letters s, m, x, r, and any combinations thereof without
any separating character in between. The same letters are allowed for the -c option of the
qsub(1) command which will overwrite the definitions in the checkpointing environment
used. The meaning of the letters is as follows:

s A job is checkpointed, aborted and, if possible, migrated if the corresponding
sge_execd(8) is shut down on the job's host. This operation is handled by the
specified migr_command.

m checkpoints are generated periodically at the min_cpu_interval interval defined by
the queue (see queue_conf(5)) in which a job executes.

x A job is checkpointed, aborted and, if possible, migrated as soon as the job gets
suspended (manually as well as automatically). This operation is handled by the
specified migr_command.

r A job will be rescheduled (not checkpointed) when the host on which the job
currently runs goes into the "unknown" state and the time interval
reschedule_unknown (see sge_conf(5)) defined in the global/local cluster
configuration is exceeded.

ENVIRONMENT VARIABLES

       SGE_BINDING and SGE_CKPT_DIR may be specified on job submission.  See submit(1).

RESTRICTIONS

       Note that the functionality of any checkpointing, migration or restart procedures provided
       by default with the Grid Engine distribution, as well as the way how they are  invoked  in
       the  ckpt_command, migr_command or restart_command parameters of any default checkpointing
       environments, should  not  be  changed;  otherwise  the  functionality  remains  the  full
       responsibility  of  the  administrator  configuring  the  checkpointing environment.  Grid
       Engine will just invoke these procedures and evaluate their exit status. If the procedures
       do  not  perform  their  tasks  properly,  or  are  not  invoked  in a proper fashion, the
       checkpointing mechanism may behave unexpectedly; Grid Engine has no means to detect this -
       all  exit  codes  are  treated  as  successful  operation  except  for  the case of kernel
       checkpointing.

       See also the restrictions in sge_ckpt(5).

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