On Mon, 5 Nov 2007, Torsten Hoefler wrote:
On Mon, Nov 05, 2007 at 04:57:19PM -0500, Brian W. Barrett wrote:
This is extremely tricky to do. How do you know which environment
variables to forward (foo in this case) and which not to (hostname).
SLURM has a better chance, since it's linux only and generally only run on
tightly controlled clusters. But there's a whole variety of things that
shouldn't be forwarded and that list differs from OS to OS.
I believe we toyed around with the "right thing" in LAM and early on with
OPen MPI and decided that it was too hard to meet expected behavior.
Some applications rely on this (I know at least two right away, Gamess
and Abinit) and they work without problems with Lam/Mpich{1,2} but not
with Open MPI. I am *not* arguing that those applications are correct (I
agree that this way of passing arguments is ugly, but it's done).
I know it's not defined in the standard but I think it's a nice
convenient functionality. E.g., setting the LD_LIBRARY_PATH to find
libmpi.so in the .bashrc is also a pain if you have multiple (Open) MPIs
installed.
LAM does not automatically propogate environment variables -- it's
behavior is almost *exactly* like Open MPI's. There might be a situation
where the environment is not quite so scrubbed if a process is started on
the same node mpirun is executed on, but it's only appearances -- in
reality, that's the environment that was alive when lamboot was executed.
With both LAM and Open MPI, there is the -x option to propogate a list of
environment variables, but that's about it. Neither will push
LD_LIBRARY_PATH by default (and there are many good reasons for that,
particularly in heterogeneous situations).
Brian
