Another important task while spawning parallel applications in a cluster is to setup a proper environment for the newly created processes on each node.
ParaStation MPI by default exports only a limited set of environment
variables to newly spawned processes, like
HOME,
USER,
SHELL or
TERM.
In addition, each currently defined environment variable can be
exported to spawned processes by adding the variable name to
the special ParaStation MPI variable PSI_EXPORTS.
E.g., within a Bourne shell (or look alike), the commands
$ PSI_EXPORTS=Variable1,Variable2,... $ export PSI_EXPORTS
will export the variables Variable1 and
Variable2 to all processes.
Accordingly, for a csh based environment, the
command
$ setenv PSI_EXPORTSVariable1,Variable2,...
will export this variables to all subsequent parallel tasks.
Beside these variables, additional variables might be
inherently set for remote processes by the
inetd(8)
, e.g. PATH or HOSTNAME.
Beside defining environment variables, mpiexec may be used to export variables. E.g.
$ mpiexec -Evarcontent...
may be used to propagate the variable
var to all processes.
Refer to mpiexec(1) for more details.
For a complete list of environment variables automatically exported by ParaStation MPI, refer to ps_environment(7).