Softpanorama

May the source be with you, but remember the KISS principle ;-)
Contents Bulletin Scripting in shell and Perl Network troubleshooting History Humor

Submitting parallel OpenMPI jobs

News SGE Commands Recommended Links SGE cheat sheet Reference SGE Submit Scripts Submitting binaries in SGE
Some interesting queue params queue_conf - Grid Engine queue configuration file format slots queue attribute        
qstat qhold qping qacct qmod qalter qdel
qhost qrsh Execution hosts Excluding SGE execution host from scheduling Restricting number of slots per server Slot hacking SGE Array Jobs
Creating and modifying SGE Queues Getting information about hosts Monitoring and Controlling Jobs Monitoring Queues Starting and Killing Daemons   ulimit problem with infiniband in SGE
SGE hostgroups Creating and modifying SGE Queues SGE Execution Host Installation SGE Parallel Environment Tips Humor Etc

SGE Configuration Intent

Parallel Example

Using OpenMPI:

#!/bin/csh
#$ -pe mpi-8 32
#$ -q *@@nehalem (<- specifies any queue that can run on the nehalem host group)
module load ompi/1.3.2-intel
mpirun  -np $NSLOTS yourapplication
The
-pe mpi-8
command specifies that this is a MPI job which should be run on nodes which have 8 cores each.
-pe mpi-*
will allow nodes with an arbitrary number of cores to be used with the caveat that the number of cores specified to be used must be an integer multiple of the number of cores on the assigned nodes. For example,
-pe mpi-* 24
can be assigned to 6-, 8-, and 12-core machines, however
-pe mpi-* 32
can only be assigned to 8-core nodes.

OpenMP Parallel Jobs

Using the -pe smp directive as detailed above is equivalent to asking permission to use multiple cores in your batch job. To run a job on multiple cores, you will also need to specify the number of cores by some method for the application. Some common methods of doing this are outlined below:

Monitoring Batch Jobs

Jobs can be monitored using the qstat command. Some useful forms:

qstat without arguments will print the status of all jobs in the queue. The output shows the following:

* The job ID number
* Priority of job
* Name of job
* ID of user who submitted job
* State of the job: States can be
** t(ransferring)
** r(unning)
* Submit or start time and date of the job
* If running - the queue in which the job is running
* The function of the running job (MASTER or SLAVE)
* The job array task ID

qstat -f Job ID Provides a full listing of the job that has the listed Job ID (or all jobs if no Job ID is given). The output shows the following: For each queue the information printed consists of:

* the queue name
* the queue type: Types or a combination of types can be
** B(atch)
** P(arallel)
* The number of used and available job slots
* The load average on the queue host
* The architecture of the queue host
* The state of the queue - Queue states or a combination of states can be
** a(larm)
** A(larm)
** s(uspended)
** d(isable)
** D(isable)
** E(rror)

qstat -j [job_list] Prints either for all pending jobs or the jobs contained in job_list the reason for not being scheduled. Additional information can be obtained my looking at the man page for qstat. Type "man qstat" for additional information.


Top Visited
Switchboard
Latest
Past week
Past month

NEWS CONTENTS

Old News ;-)

Sun Grid Engine Quick-Start

The following sections give an overview of how to submit jobs, monitor job and host status, and how to use the SGE parallel environment.

Submitting Jobs

A job in SGE represents a task to be performed on a node in the cluster and contains the command line used to start the task. A job may have specific resource requirements but in general should be agnostic to which node in the cluster it runs on as long as its resource requirements are met.

Note

All jobs require at least one available slot on a node in the cluster to run.

Submitting jobs is done using the qsub command. Let’s try submitting a simple job that runs the hostname command on a given cluster node:

sgeadmin@master:~$ qsub -V -b y -cwd hostname
Your job 1 ("hostname") has been submitted

Notice that the qsub command, when successful, will print the job number to stdout. You can use the job number to monitor the job’s status and progress within the queue as we’ll see in the next section.

Monitoring Jobs in the Queue

Now that our job has been submitted, let’s take a look at the job’s status in the queue using the command qstat:

sgeadmin@master:~$ qstat
job-ID prior name user state submit/start at queue slots ja-task-ID
-------------------------------------------------------------------
1 0.00000 hostname sgeadmin qw 09/09/2009 14:58:00 1
sgeadmin@master:~$

From this output, we can see that the job is in the qw state which stands for queued and waiting. After a few seconds, the job will transition into a r, or running, state at which point the job will begin executing:

sgeadmin@master:~$ qstat
job-ID  prior   name       user         state submit/start at     queue  slots ja-task-ID
-----------------------------------------------------------------------------------------
1 0.00000 hostname   sgeadmin     r     09/09/2009 14:58:14                1
sgeadmin@master:~$

Once the job has finished, the job will be removed from the queue and will no longer appear in the output of qstat:

sgeadmin@master:~$ qstat
sgeadmin@master:~$

Now that the job has finished let’s move on to the next section to see how we view a job’s output.

Viewing a Job’s Output

Sun Grid Engine creates stdout and stderr files in the job’s working directory for each job executed. If any additional files are created during a job’s execution, they will also be located in the job’s working directory unless explicitly saved elsewhere.

The job’s stdout and stderr files are named after the job with the extension ending in the job’s number.

For the simple job submitted above we have:

sgeadmin@master:~$ ls hostname.*
hostname.e1 hostname.o1
sgeadmin@master:~$ cat hostname.o1
node001
sgeadmin@master:~$ cat hostname.e1
sgeadmin@master:~$

Notice that Sun Grid Engine automatically named the job hostname and created two output files: hostname.e1 and hostname.o1. The e stands for stderr and the o for stdout. The 1 at the end of the files’ extension is the job number. So if the job had been named my_new_job and was job #23 submitted, the output files would look like:

my_new_job.e23 my_new_job.o23

Monitoring Cluster Usage

After a while you may be curious to view the load on Sun Grid Engine. To do this, we use the qhost command:

sgeadmin@master:~$ qhost
HOSTNAME ARCH NCPU LOAD MEMTOT MEMUSE SWAPTO SWAPUS
-------------------------------------------------------------------------------
global - - - - - - -
master lx24-x86 1 0.00 1.7G 62.7M 896.0M 0.0
node001 lx24-x86 1 0.00 1.7G 47.8M 896.0M 0.0

The output shows the architecture (ARCH), number of cpus (NCPU), the current load (LOAD), total memory (MEMTOT), and currently used memory (MEMUSE) and swap space (SWAPTO) for each node.

You can also view the average load (load_avg) per node using the ‘-f’ option to qstat:

sgeadmin@master:~$ qstat -f
queuename qtype resv/used/tot. load_avg arch states
---------------------------------------------------------------------------------
all.q@master.c BIP 0/0/1 0.00 lx24-x86
---------------------------------------------------------------------------------
all.q@node001.c BIP 0/0/1 0.00 lx24-x86

Creating a Job Script

In the ‘Submitting a Job’ section we submitted a single command hostname. This is useful for simple jobs but for more complex jobs where we need to incorporate some logic we can use a so-called job script. A job script is essentially a bash script that contains some logic and executes any number of external programs/scripts:

#!/bin/bash
echo "hello from job script!"
echo "the date is" `date`
echo "here's /etc/hosts contents:"
cat /etc/hosts
echo "finishing job :D"

As you can see, this script simply executes a few commands (such as echo, date, cat, etc.) and exits. Anything printed to the screen will be put in the job’s stdout file by Sun Grid Engine.

Since this is just a bash script, you can put any form of logic necessary in the job script (i.e. if statements, while loops, for loops, etc.) and you may call any number of external programs needed to complete the job.

Let’s see how you run this new job script. Save the script above to /home/sgeadmin/jobscript.sh on your StarCluster and execute the following as the sgeadmin user:

sgeadmin@master:~$ qsub -V jobscript.sh
Your job 6 ("jobscript.sh") has been submitted

Now that the job has been submitted, let’s call qstat periodically until the job has finished since this job should only take a second to run once it’s executed:

sgeadmin@master:~$ qstat
job-ID prior name user state submit/start at queue slots ja-task-ID
-------------------------------------------------------------------
6 0.00000 jobscript. sgeadmin qw 09/09/2009 16:18:43 1

sgeadmin@master:~$ qstat
job-ID prior name user state submit/start at queue slots ja-task-ID
-------------------------------------------------------------------
6 0.00000 jobscript. sgeadmin qw 09/09/2009 16:18:43 1

sgeadmin@master:~$ qstat
job-ID prior name user state submit/start at queue slots ja-task-ID
-------------------------------------------------------------------
6 0.00000 jobscript. sgeadmin qw 09/09/2009 16:18:43 1

sgeadmin@master:~$ qstat
job-ID prior name user state submit/start at queue slots ja-task-ID
-------------------------------------------------------------------
6 0.00000 jobscript. sgeadmin qw 09/09/2009 16:18:43 1

sgeadmin@master:~$ qstat
job-ID prior name user state submit/start at queue slots ja-task-ID
-------------------------------------------------------------------
6 0.55500 jobscript. sgeadmin r 09/09/2009 16:18:57 all.q@node001.c 1

sgeadmin@master:~$ qstat
sgeadmin@master:~$

Now that the job is finished, let’s take a look at the output files:

sgeadmin@master:~$ ls jobscript.sh*
jobscript.sh jobscript.sh.e6 jobscript.sh.o6
sgeadmin@master:~$ cat jobscript.sh.o6
hello from job script!
the date is Wed Sep 9 16:18:57 UTC 2009
here's /etc/hosts contents:
# Do not remove the following line or programs that require network functionality will fail
127.0.0.1 localhost.localdomain localhost
10.252.167.143 master
10.252.165.173 node001
finishing job :D
sgeadmin@master:~$ cat jobscript.sh.e6
sgeadmin@master:~$

We see from looking at the output that the stdout file contains the output of the echo, date, and cat statements in the job script and that the stderr file is blank meaning there were no errors during the job’s execution. Had something failed, such as a command not found error for example, these errors would have appeared in the stderr file.

Deleting a Job from the Queue

What if a job is stuck in the queue, is taking too long to run, or was simply started with incorrect parameters? You can delete a job from the queue using the qdel command in Sun Grid Engine. Below we launch a simple ‘sleep’ job that sleeps for 10 seconds so that we can kill it using qdel:

sgeadmin@master:~$ qsub -b y -cwd sleep 10
Your job 3 ("sleep") has been submitted
sgeadmin@master:~$ qdel 3
sgeadmin has registered the job 3 for deletion

After running qdel you’ll notice the job is gone from the queue:

sgeadmin@master:~$ qstat
sgeadmin@master:~$

OpenMPI and Sun Grid Engine

Note

OpenMPI Parallel Environment

StarCluster by default sets up a parallel environment, called “orte”, that has been configured for OpenMPI integration within SGE and has a number of slots equal to the total number of processors in the cluster. You can inspect the SGE parallel environment by running:

sgeadmin@ip-10-194-13-219:~$ qconf -sp orte
pe_name            orte
slots              16
user_lists         NONE
xuser_lists        NONE
start_proc_args    /bin/true
stop_proc_args     /bin/true
allocation_rule    $fill_up
control_slaves     TRUE
job_is_first_task  FALSE
urgency_slots      min
accounting_summary FALSE

This is the default configuration for a two-node, c1.xlarge cluster (16 virtual cores).

Parallel Environment Allocation Rule

Notice the allocation_rule setting in the output of the qconf command in the previous section. This rule defines how to assign slots to a job. By default StarCluster uses the fill_up allocation rule. This rule causes SGE to greedily take all available slots on as many cluster nodes as needed to fulfill the slot requirements of a given job. For example, if a user requests 8 slots and a single node has 8 slots available, that job will run entirely on one node. If 5 slots are available on one node and 3 on another, it will take all 5 on that node, and all 3 on the other node.

The allocation rule can also be configured to distribute the slots around the cluster as evenly as possible by using the round_robin allocation_rule. For example, if a job requests 8 slots, it will go to the first node, grab a slot if available, move to the next node and grab a single slot if available, and so on wrapping around the cluster nodes again if necessary to allocate 8 slots to the job.

Finally, setting the allocation_rule to an integer number will cause the parallel environment to take a fixed number of slots from each host when allocating the job by specifying an integer for the allocation_rule. For example, if the allocation_rule is set to 1 then all slots have to reside on different hosts. If the special value $pe_slots is used then all slots for the parallel job must be allocated entirely on a single host in the cluster.

You can change the allocation rule for the orte parallel environment at any time using:

$ qconf -mp orte

This will open up vi (or any editor defined in the EDITOR environment variable) and let you edit the parallel environment settings. To change from fill_up to round_robin in the above example, change the allocation_rule line from:

allocation_rule    $fill_up

to:

allocation_rule    $round_robin

You can also change the rule to the pe_slots mode:

allocation_rule    $pe_slots

or specify a fixed number of slots per host to assign when allocating the job:

allocation_rule    1

After making the change and saving the file you can verify your settings using:

sgeadmin@ip-10-194-13-219:~$ qconf -sp orte
pe_name            orte
slots              16
user_lists         NONE
xuser_lists        NONE
start_proc_args    /bin/true
stop_proc_args     /bin/true
allocation_rule    $round_robin
control_slaves     TRUE
job_is_first_task  FALSE
urgency_slots      min
accounting_summary FALSE

Submitting OpenMPI Jobs using a Parallel Environment

The general workflow for running MPI code is:

  1. Compile the code using mpicc, mpicxx, mpif77, mpif90, etc.
  2. Copy the resulting executable to the same path on all nodes or to an NFS-shared location on the master node

Note

It is important that the path to the executable is identical on all nodes for mpirun to correctly launch your parallel code. The easiest approach is to copy the executable somewhere under /home on the master node since /home is NFS-shared across all nodes in the cluster.

  1. Run the code on X number of machines using:

    $ mpirun -np X -hostfile myhostfile ./mpi-executable arg1 arg2 [...]
    

where the hostfile looks something like:

$ cat /path/to/hostfile
master  slots=2
node001 slots=2
node002 slots=2
node003 slots=2

However, when using an SGE parallel environment with OpenMPI you no longer have to specify the -np, -hostfile, -host, etc. options to mpirun. This is because SGE will automatically assign hosts and processors to be used by OpenMPI for your job. You also do not need to pass the –byslot and –bynode options to mpirun given that these mechanisms are now handled by the fill_up and round_robin modes specified in the SGE parallel environment.

Instead of using the above formulation create a simple job script that contains a very simplified mpirun call:

$ cat myjobscript.sh
mpirun /path/to/mpi-executable arg1 arg2 [...]

Then submit the job using the qsub command and the orte parallel environment automatically configured for you by StarCluster:

$ qsub -pe orte 24 ./myjobscript.sh

The -pe option species which parallel environment to use and how many slots to request. The above example requests 24 slots (or processors) using the orte parallel environment. The parallel environment automatically takes care of distributing the MPI job amongst the SGE nodes using the allocation_rule defined in the environment’s settings.

You can also do this without a job script like so:

$ cd /path/to/executable
$ qsub -b y -cwd -pe orte 24 mpirun ./mpi-executable arg1 arg2 [...]



Etc

FAIR USE NOTICE This site contains copyrighted material the use of which has not always been specifically authorized by the copyright owner. We are making such material available in our efforts to advance understanding of environmental, political, human rights, economic, democracy, scientific, and social justice issues, etc. We believe this constitutes a 'fair use' of any such copyrighted material as provided for in section 107 of the US Copyright Law. In accordance with Title 17 U.S.C. Section 107, the material on this site is distributed without profit exclusivly for research and educational purposes.   If you wish to use copyrighted material from this site for purposes of your own that go beyond 'fair use', you must obtain permission from the copyright owner. 

ABUSE: IPs or network segments from which we detect a stream of probes might be blocked for no less then 90 days. Multiple types of probes increase this period.  

Society

Groupthink : Two Party System as Polyarchy : Corruption of Regulators : Bureaucracies : Understanding Micromanagers and Control Freaks : Toxic Managers :   Harvard Mafia : Diplomatic Communication : Surviving a Bad Performance Review : Insufficient Retirement Funds as Immanent Problem of Neoliberal Regime : PseudoScience : Who Rules America : Neoliberalism  : The Iron Law of Oligarchy : Libertarian Philosophy

Quotes

War and Peace : Skeptical Finance : John Kenneth Galbraith :Talleyrand : Oscar Wilde : Otto Von Bismarck : Keynes : George Carlin : Skeptics : Propaganda  : SE quotes : Language Design and Programming Quotes : Random IT-related quotesSomerset Maugham : Marcus Aurelius : Kurt Vonnegut : Eric Hoffer : Winston Churchill : Napoleon Bonaparte : Ambrose BierceBernard Shaw : Mark Twain Quotes

Bulletin:

Vol 25, No.12 (December, 2013) Rational Fools vs. Efficient Crooks The efficient markets hypothesis : Political Skeptic Bulletin, 2013 : Unemployment Bulletin, 2010 :  Vol 23, No.10 (October, 2011) An observation about corporate security departments : Slightly Skeptical Euromaydan Chronicles, June 2014 : Greenspan legacy bulletin, 2008 : Vol 25, No.10 (October, 2013) Cryptolocker Trojan (Win32/Crilock.A) : Vol 25, No.08 (August, 2013) Cloud providers as intelligence collection hubs : Financial Humor Bulletin, 2010 : Inequality Bulletin, 2009 : Financial Humor Bulletin, 2008 : Copyleft Problems Bulletin, 2004 : Financial Humor Bulletin, 2011 : Energy Bulletin, 2010 : Malware Protection Bulletin, 2010 : Vol 26, No.1 (January, 2013) Object-Oriented Cult : Political Skeptic Bulletin, 2011 : Vol 23, No.11 (November, 2011) Softpanorama classification of sysadmin horror stories : Vol 25, No.05 (May, 2013) Corporate bullshit as a communication method  : Vol 25, No.06 (June, 2013) A Note on the Relationship of Brooks Law and Conway Law

History:

Fifty glorious years (1950-2000): the triumph of the US computer engineering : Donald Knuth : TAoCP and its Influence of Computer Science : Richard Stallman : Linus Torvalds  : Larry Wall  : John K. Ousterhout : CTSS : Multix OS Unix History : Unix shell history : VI editor : History of pipes concept : Solaris : MS DOSProgramming Languages History : PL/1 : Simula 67 : C : History of GCC developmentScripting Languages : Perl history   : OS History : Mail : DNS : SSH : CPU Instruction Sets : SPARC systems 1987-2006 : Norton Commander : Norton Utilities : Norton Ghost : Frontpage history : Malware Defense History : GNU Screen : OSS early history

Classic books:

The Peter Principle : Parkinson Law : 1984 : The Mythical Man-MonthHow to Solve It by George Polya : The Art of Computer Programming : The Elements of Programming Style : The Unix Hater’s Handbook : The Jargon file : The True Believer : Programming Pearls : The Good Soldier Svejk : The Power Elite

Most popular humor pages:

Manifest of the Softpanorama IT Slacker Society : Ten Commandments of the IT Slackers Society : Computer Humor Collection : BSD Logo Story : The Cuckoo's Egg : IT Slang : C++ Humor : ARE YOU A BBS ADDICT? : The Perl Purity Test : Object oriented programmers of all nations : Financial Humor : Financial Humor Bulletin, 2008 : Financial Humor Bulletin, 2010 : The Most Comprehensive Collection of Editor-related Humor : Programming Language Humor : Goldman Sachs related humor : Greenspan humor : C Humor : Scripting Humor : Real Programmers Humor : Web Humor : GPL-related Humor : OFM Humor : Politically Incorrect Humor : IDS Humor : "Linux Sucks" Humor : Russian Musical Humor : Best Russian Programmer Humor : Microsoft plans to buy Catholic Church : Richard Stallman Related Humor : Admin Humor : Perl-related Humor : Linus Torvalds Related humor : PseudoScience Related Humor : Networking Humor : Shell Humor : Financial Humor Bulletin, 2011 : Financial Humor Bulletin, 2012 : Financial Humor Bulletin, 2013 : Java Humor : Software Engineering Humor : Sun Solaris Related Humor : Education Humor : IBM Humor : Assembler-related Humor : VIM Humor : Computer Viruses Humor : Bright tomorrow is rescheduled to a day after tomorrow : Classic Computer Humor

The Last but not Least


Copyright © 1996-2016 by Dr. Nikolai Bezroukov. www.softpanorama.org was created as a service to the UN Sustainable Development Networking Programme (SDNP) in the author free time. This document is an industrial compilation designed and created exclusively for educational use and is distributed under the Softpanorama Content License.

The site uses AdSense so you need to be aware of Google privacy policy. You you do not want to be tracked by Google please disable Javascript for this site. This site is perfectly usable without Javascript.

Original materials copyright belong to respective owners. Quotes are made for educational purposes only in compliance with the fair use doctrine.

FAIR USE NOTICE This site contains copyrighted material the use of which has not always been specifically authorized by the copyright owner. We are making such material available to advance understanding of computer science, IT technology, economic, scientific, and social issues. We believe this constitutes a 'fair use' of any such copyrighted material as provided by section 107 of the US Copyright Law according to which such material can be distributed without profit exclusively for research and educational purposes.

This is a Spartan WHYFF (We Help You For Free) site written by people for whom English is not a native language. Grammar and spelling errors should be expected. The site contain some broken links as it develops like a living tree...

You can use PayPal to make a contribution, supporting development of this site and speed up access. In case softpanorama.org is down you can use the at softpanorama.info

Disclaimer:

The statements, views and opinions presented on this web page are those of the author (or referenced source) and are not endorsed by, nor do they necessarily reflect, the opinions of the author present and former employers, SDNP or any other organization the author may be associated with. We do not warrant the correctness of the information provided or its fitness for any purpose.

Last modified: November, 09, 2015