Make sure you’re logged in on your Ubuntu system using a user which has sudo access
Open the terminal
Create a new user called 'mpiuser'
sudo adduser mpiuser
Give sudo access to the newly created user
sudo usermod -aG sudo mpiuser
To execute commands with the priveleges of the newly created user
su mpiuser
Install OpenMPI
sudo apt-get install openmpi-bin
Install SSH
sudo apt-get install openssh-server
Get your IP address
ifconfig
Add the IP addresses of master and slave PCs to the host file
sudo nano /etc/hosts
Master <master up address>
Slave <slave ip address>
After you're done writing them, use the following keyboard shortcuts to properly write to and exit the file "CTRL+O ENTER CTRL+X"
Generate a key (When prompted DO NOT enter any passphrase)
ssh-keygen
Copy the generated key onto the slave PC (make sure to replace the prompts below with your own ip addresses)
ssh-copy-id yourmasterusername@slave-ip-address
Test the SSH connection to the slave computer:
ssh your-master-username@slave-ip-address
It should be able to log in to the terminal of the slave PC
Now exit from being logged into the slave pc
exit
Now switch users and login to the mpiuser you created (It will be saved as the First Name you chose)
Write an mpi program (hello world in this case) and save the file with the same name and in the same directory for both the PCs (I will be putting it in Documents). Our program was taken from: https://mpitutorial.com/tutorials/mpi-hello-world/
Open the terminal
Change the directory to the place where you saved your mpi program's file (Documents in our case)
cd Documents
Compile the mpi program's file
mpicc mpihelloworld.c -o mpi_hello_world
Now finally execute the file on your master computer
mpiexec --oversubscribe -n 20 -host <master-ip-address>,<slave-ip-address> ./<the executable mpi file’s name>
In our case: mpiexec --oversubscribe -n 20 -host 10.2.70.156,10.2.70.78 ./mpi_hello_world
Make sure you’re logged in on your Ubuntu system using a user which has sudo access
Open terminal
Make a new user
sudo adduser mpiuser
Give sudo access to the newly created user
sudo usermod -aG sudo mpiuser
To execute commands with the priveleges of the newly created user
su mpiuser
Install OpenMPI
sudo apt-get install openmpi-bin
Install SSH
sudo apt-get install openssh-server
Get your IP address
ifconfig
Add the IP addresses of master and slave PCs to the host file
sudo nano /etc/hosts
Master <master up address>
Slave <slave ip address>
After you're done writing them, use the following keyboard shortcuts to properly write to and exit the file
"CTRL+O ENTER CTRL+X"
Test the SSH connection to the master computer
ssh your-slave-username@master-ip-address
It should be able to log in to the terminal of the master PC
Now exit from being logged into the master pc
exit
Now switch users and login to the mpiuser you created (It will be saved as the First Name you chose)
Write an mpi program (hello world in this case) and save the file with the same name and in the same directory for both the PCs (I will be putting it in Documents). Our program was taken from: https://mpitutorial.com/tutorials/mpi-hello-world/
Open the terminal
Change the directory to the place where you saved your mpi program's file (Documents in our case)
cd Documents
Compile the mpi program's file
mpicc mpihelloworld.c -o mpi_hello_world
Go check with your master PC and see if the program is executing as expected (fingers crossed it is 🤞)
If you get an error along the lines of 'can not find the mpi.h file' while compiling or executing your mpi program. Try running these commands:
sudo apt-get remove libopenmpi-dev openmpi-bin
sudo apt-get autoremove
sudo apt-get install libopenmpi-dev openmpi-bin
Ignore it. It's not an error.
If you get an error with something along the lines of "mpiexec was unable to launch the specified application as it could not accessor execute an executable":
You have either:
- not created the mpi program in the same directories for both the PCs
- not compiled the program (the mpicc command) on either the master or the slave PC