Description

Hydra is the default name service for MPI’s name publishing features (MPI_PUBLISH_NAME/MPI_LOOKUP_NAME). For programs launched by separate hydra instances, a separate nameserver mechanism need be launched in order for the name publishing to work across multiple process managers.

This can be achieved with hydra_nameserver. For example:
    shell@myhost1$ hydra_nameserver &
    shell@myhost1$ mpiexec -hosts myhost1,myhost2 -n 4 -nameserver myhost1 ./a.out