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Subject: Re: [OMPI devel] HOSTNAME environment variable
From: Ralph Castain (rhc_at_[hidden])
Date: 2010-01-22 10:07:29


Hi Nadia

That sounds like a bug in your SLURM config file - SLURM certainly doesn't propagate "hostname" by default as that would definitely mess things up for more than OMPI.

Are you sure that SLURM is propagating the environment (something I have never seen before)? Or is OMPI mistakenly picking it up and propagating it?

On Jan 22, 2010, at 7:25 AM, Nadia Derbey wrote:

> Hi,
>
> I'm wondering whether the HOSTNAME environment variable shouldn't be
> handled as a "special case" when the orted daemons launch the remote
> jobs. This particularly applies to batch schedulers where the caller's
> environment is copied to the remote job: we are inheriting a $HOSTNAME
> which is the name of the host mpirun was called from:
>
> I tried to run the following small test (see getenv.c in attachment - it
> substantially gets the hostname once through $HOSTNAME, and once through
> gethostname(2)):
>
> ------------
> [derbeyn_at_pichu0 ~]$ hostname
> pichu0
> [derbeyn_at_pichu0 ~]$ salloc -N 2 -p pichu mpirun ./getenv
> salloc: Granted job allocation 358789
> Processor 0 of 2 on $HOSTNAME pichu0: Hello World
> Processor 0 of 2 on host pichu93: Hello World
> Processor 1 of 2 on $HOSTNAME pichu0: Hello World
> Processor 1 of 2 on host pichu94: Hello World
> salloc: Relinquishing job allocation 358789
> ------------
>
> Shouldn't we be getting the same value when using getenv("HOSTNAME") and gethsotname()?
> Applying the following small patch, we actually do.
>
> Regards,
> Nadia
>
> --------------
>
> Do not propagate the HOSTNAME environment variable on remote hosts
>
> diff -r 4ab256be2a17 orte/orted/orted_main.c
> --- a/orte/orted/orted_main.c Wed Jan 20 16:45:07 2010 +0100
> +++ b/orte/orted/orted_main.c Fri Jan 22 14:54:02 2010 +0100
> @@ -299,12 +299,17 @@ int orte_daemon(int argc, char *argv[])
> */
> orte_launch_environ = opal_argv_copy(environ);
>
> + /*
> + * Set HOSTNAME to the actual hostname in order to avoid propagating
> + * the caller's HOSTNAME.
> + */
> + gethostname(hostname, 100);
> + opal_setenv("HOSTNAME", hostname, true, &orte_launch_environ);
>
> /* if orte_daemon_debug is set, let someone know we are alive right
> * away just in case we have a problem along the way
> */
> if (orted_globals.debug) {
> - gethostname(hostname, 100);
> fprintf(stderr, "Daemon was launched on %s - beginning to initialize\n", hostname);
> }
>
> <getenv.c>_______________________________________________
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