I am trying to get a simple example working across 2 amazon nodes. When I run locally, its all fine. Then when I use -machinefile to launch across both nodes, the sample application on the slave node throws an exception. forrtl 157. I can run using -machinefile and just run both locally. And I can run using -machine file and just run everything on the remote node. But when I add both addresses to the hosts.txt, it seems the sample application on the slave node crashes. Node names are the same as they are identical amazon images. I have tried disabling firewalls. It always crashs when the slave node (or rank 1) calls MPI_SEND. However, when I run with out -machinefile, and just run on the same machine,it all works fine with -n 4 etc.
Any pointers as to where I should start looking, thanks.
Here is my sample application: