Slaton's Tips:
Configure a SSH public key for IMAGIC MPI programs

IMAGIC is a product of Image Science Software GmbH in Berlin, Germany.

Comments/corrections welcome.

1. Create a new SSH authentication key

Each user will first need to generate a ssh authentication key with a blank passphrase so that mpi can use ssh (instead of rsh, or some other means) for launching parallel threads without explicit user input.

$ ssh-keygen -C mpi_batchmode -t rsa -b 2048 -f ~/.ssh/mpi_batchmode -N ""

2. Authorize the key for incoming localhost logins

Next, this key needs to be added to ~/.ssh/authorized_keys. (Note: if you don't already have this file, just created an empty file with the touch command and chmod it to permissions 600.)

$ cat ~/.ssh/mpi_batchmode.pub >> ~/.ssh/authorized_keys

3. Configure the ssh client to use your new key

You need to edit your user ssh config file, ~/.ssh/config, and specify that this batchmode key is to be used for connections to the local machine (only). This is done with the Host keyword. Add a section like the following to the TOP of the config file. It must be above the Host * wildcard section, if it exists.

Host toro.university.edu toro
  IdentityFile ~/.ssh/mpi_batchmode

IMAGIC determines the local machine's hostname according to the output of uname -n, so make sure the same name is used here. In this case toro is just a short convenience alias.

4. Test your configuration

To test the ssh configuration, the following command should give a listing of your home directory, without asking for a password or passphrase.

$ ssh toro ls

If a password is requested, or an error results, the configuration is incorrect. Start over with step one and try again.