Run Hydra (mpiexec) locally gives strange SSH error

Question

I am trying to run example code from this question: MPI basic example doesn't work but when I do:

$ mpirun -np 2 mpi_test

I get this:

ssh: Could not resolve hostname wvxvw-laptop: Name or service not known

And then the program hangs until interrupted.

wvxvw-laptop is the "host name" of my laptop, which is just that, really, a laptopt...

All I want is to try to run the example code, not to set up a network cluster or anything like that.

What did I miss? I'm reading the wiki page http://wiki.mpich.org/mpich/index.php/Using_the_Hydra_Process_Manager but I can't understand what is the reason.

Sorry, I'm very new to this.

---

Some more verbose output:

/usr/bin/ssh -x wvxvw-laptop "/usr/lib64/mpich/bin/hydra_pmi_proxy" \
--control-port wvxvw-laptop:54320 --debug --rmk user --launcher ssh \
--demux poll --pgid 0 --retries 10 --usize -2 --proxy-id 0 

Formatted for readability. I'm not quite sure why is this even supposed to work (I've never used ssh -x not sure what it is supposed to do :/

Answer 1

mpirun execute your program on all node registered on your mpi cluster. MPI use the computer name so you can edit your /etc/hosts to add an entry for wvxvw-laptop