A question about subprocess

Karthik Gurusamy kar1107 at gmail.com
Thu Oct 4 08:12:32 CEST 2007


On Oct 3, 9:46 am, JD <Jiandong... at gmail.com> wrote:
> Hi,
>
> I want send my jobs over a whole bunch of machines (using ssh). The
> jobs will need to be run in the following pattern:
>
> (Machine A)   (Machine B)  (Machine C)
>
> Job A1             Job B1            Job C1
>
>  Job A2           Job B2            etc
>
>  Job A3          etc
>
>  etc
>
> Jobs runing on machine A, B, C should be in parallel, however, for
> each machine, jobs should run one after another.
>
> How can I do it with the subprocess?

subprocess is not network aware. What you can do is write a simple
python script say run_jobs.py which can take in a command-line
argument (say A or B or C) and will fire a sequence of subprocesses to
execute a series of jobs. This will ensure the serialization condition
like A2 starting after A1's completion.

Now you can write a load distributer kind of script which uses ssh to
login to the various machines and run run_jobs.py with appropriate
argument (Here I assume all machines have access to run_jobs.py -- say
it may reside on a shared mounted file-system).

e.g. in outer script:

ssh machine-A run_jobs.py A
ssh machine-B run_jobs.py B
ssh machine-B run_jobs.py C
...

You may want to fire all these at once so that they all execute in
parallel.

Karthik

>
> Thanks,
>
> JD





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