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

Provided by: gridengine-common_8.1.9+dfsg-12_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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