Mastering C++ Multithreading

Creating the MPI host file

As mentioned earlier, in order to run a job on other nodes, we need to specify these nodes. The easiest way to do this is to create a file containing the names of the compute nodes we wish to use, along with optional parameters.

To allow us to use names for the nodes instead of IP addresses, we have to modify the operating system's host file first: for example, /etc/hosts on Linux:

    192.168.0.1 master
    192.168.0.2 node0
    192.168.0.3 node1

Next we create a new file which will be the host file for use with MPI:

    master
    node0
    node1

With this configuration, a job would be executed on both compute nodes, as well as the master node. We can take the master node out of this file to prevent this.

Without any optional parameter ...