Library level - MPI

In order to test the scalability of the system, OpenMPI support was added to the cluster. OpenMPI is a library for message passing that allows running tasks across multiple nodes. OpenMPI was installed on the shared file system and the configuration steps for creating new nodes were changed to add OpenMPI to the PATH and LD LIBRARY PATH.

Because OpenMPI uses random port numbers for all its communication, a new policy was added to the virtual cloud network that allows all nodes on that subnetwork to communicate with each other through any port. Moreover, the firewall configuration for the nodes was edited to open up all ports.cCommands added to initialization script:

firewall-cmd --permanent --add-port=0-65535/tcp
firewall-cmd --add-port=0-65535/tcp

Example running MPI program:

[codrin@mgmt example1]$ sbatch mpi_submit
Submitted batch job 73
#After some time#
[codrin@mgmt example1]$ cat slurm-73.out
start
end
Hello, world; from host compute006: process 1 of 8
Hello, world; from host compute006: process 0 of 8
Hello, world; from host compute008: process 5 of 8
Hello, world; from host compute008: process 4 of 8
Hello, world; from host compute009: process 7 of 8
Hello, world; from host compute009: process 6 of 8
Hello, world; from host compute007: process 3 of 8
Hello, world; from host compute007: process 2 of 8