Remote Execution With qrsh

qrsh is built around the standard rsh facility. See the information that is provided in sge-root/3rd_party for details on the involvement of rsh. qrsh can be used for various purposes, including the following:

• To provide remote execution of interactive applications that use the grid engine system comparable to the standard UNIX facility rsh. rsh is also called remsh on HP-UX systems.

• To offer interactive login session capabilities that use the grid engine system, similar to the standard UNIX facility rlogin. qlogin is still required as a grid engine system's representation of the UNIX telnet facility.

• To allow for the submission of batch jobs that support terminal I/O (standard output, standard error, and standard input) and terminal control.

• To provide a way to submit a standalone program that is not embedded in a shell script.

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  Note –

  You can also submit scripts with qrsh by using the -b n option. For more information, see the qrsh man page.

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• To provide a submission client that remains active while a batch job is pending or running and that goes away only if the job finishes or is cancelled.

• To allow for the grid engine system-controlled remote running of job tasks within the framework of the dispersed resources allocated by parallel jobs. See Tight Integration of Parallel Environments and Grid Engine Software in Sun N1 Grid Engine 6.1 Administration Guide.

By virtue of these capabilities, qrsh is the major enabling infrastructure for the implementation of the qtcsh and the qmake facilities. qrsh is also used for the tight integration of the grid engine system with parallel environments such as MPI or PVM.

Invoking Transparent Remote Execution With qrsh

Type the qrsh command, adding options and arguments according to the following syntax:

% qrsh	[options] program|shell-script [arguments] \
	[> stdout] [>&2 stderr] [< stdin]

qrsh understands almost all options of qsub. qrsh provides the following options:

• -now yes|no – -now yes specifies that the job is scheduled immediately. The job is rejected if no appropriate resources are available. -now yes is the default. -now no specifies that the job is queued like a batch job if the job cannot be started at submission time.

• -inherit – qrsh does not go through the scheduling process to start a job-task. Instead, qrsh assumes that the job is embedded in a parallel job that already has allocated suitable resources on the designated remote execution host. This form of qrsh is commonly used in qmake and in a tight parallel environment integration. The default is not to inherit external job resources.

• -binary yes|no – When specified with the n option, enables you to use qrsh to submit script jobs.

• -noshell – With this option, you do not start the command line that is given to qrsh in a user's login shell. Instead, you execute the command without the wrapping shell. Use this option to speed up execution, as some overhead, such as the shell startup and the sourcing of shell resource files, is avoided.

• -nostdin – Suppresses the input stream STDIN. With this option set, qrsh passes the -n option to the rsh command. Suppression of the input stream is especially useful if multiple tasks are executed in parallel using qrsh, for example, in a make process. Which process gets the input is undefined.

• -verbose – This option presents output on the scheduling process. -verbose is mainly intended for debugging purposes and is therefore switched off by default.