How to set the host file on Devcloud for running MPI programs

[Viet]

Dear Devcloud administrator and supporter,

I would like to run the below tutorial program on Devcloud:

https://software.intel.com/content/www/us/en/develop/documentation/itac-vtune-mpi-openmp-tutorial-lin/top/build-and-configure-application.html#build-and-configure-application_TOOLS

Please let me know how to set the host file on Devcloud for running the MPI program.

Thank you for everything you can provide.

Viet

[ArunJ_Intel · Accepted solution]

Hi Viat,

To run mpi aplications on devcloud you could request multiple nodes interactively with qsub command. For eg the below command requests two nodes

qsub -I -l nodes=2:gpu:ppn=2 -d .

Once you are in the compute node(s) the you can use the below command to get the node names that you could provide in hostfile.

qstat -xf 

This would return an XML. In this XML, the <exec_host> tag has the hostnames of the 2 nodes(as we requested 2) that are available

eg: 

<exec_host>s001-n178/0-1+s001-n181/0-1</exec_host>

Then you should use the hostnames of the nodes in your hostfile. FOr the above example hostfile.txt would be

s001-n178

s001-n181

Regards

Arun

[Viet]

Dear Arun,

Thank you so much for your response.
I was able to get node names in Devcloud to create a hosts file. I still have a few questions about it.

How many nodes can I use in Devcloud?

In my case, I don't have to use gpu and ppn. What's the qsub command for this?
Are there any guides on how to run the qsub command in Devcloud?

Thanks for any help you can provide.

Best,

Viet.

[ArunJ_Intel]

Hi Viet,

The maximum nodes that can be requested per job is currently 4(due to queue resource limits). 

ppn is a mandatory parameter for devclouds qsub command and 2 is the only accepted value for ppn in devcloud. You could request a node without gpu using the below command.

qsub -I -l nodes=4:ppn=2

Additionally you could get all available devcloud node configurations with the below command.

pbsnodes | grep properties | sort -u

You could specify any property to be made mandatory for the nodes allotted to you. For example in my first comment I had requested nodes by giving gpu as a requirement. You could similarly pass a requirement by specifying a property from any of the options in comma separated properties. 

The below guide would help with job submission on devcloud

https://devcloud.intel.com/oneapi/documentation/job-submission/

Thanks

Arun 

[Viet]

Dear Arun,

It is clear to me now.

Many thanks for your help.

Best, Viet.

[ArunJ_Intel]

Thanks Viet for the confirmation we wouldn't be monitoring this thread further. Please feel free to raise a new thread in case of any further issues.

Arun Jose