Google Cloud MPI

How to run google cloud mpi project with Linux

Generate SSH keypair on your local machine

1. Run ssh-keygen -t rsa in your terminal
2. Enter filename for key(eg. )
3. Enter your password

Send your public key to the cloud instance(only master)

1. Run scp <USER>.pub <USER>@<EXTERNAL_IP_OF_FIRST_INSANCE>:/home/<USER>/.ssh
2. Add it to authorized_keys. To do this run cat .ssh/<USER>.pub >> .ssh/authorized_keys

Create your VM instance

1. vCPU → 4 vCPU
2. Boot disk: Ubuntu 17.10 LTS
3. Allow HTTP traffic

Set up your environment

1. Run following commands: sudo apt-get install mpich sudo apt-get install gcc
2. Upload and compile your code
3. Upload your private key and run following commands: eval ssh-agent ssh-add <PRIVATE_KEY_NAME>

Verify SSH connection

To do this try to SSH into machine ssh -i <USER> <USER>@<EXTERNAL_IP_OF_FIRST_INSANCE>. You should be greated with welcome message.

Make a copy of the instance

1. Create snapshot based on the instance-1
2. Create instance-2 based on the snapshot.

Verify SSH connection to instance-2

1. Run ssh -i <USER> <USER>@<EXTERNAL_IP_OF_SECOND_INSTANCE>
2. You should see welcome message.

Copy your private key to instance-1

We need this to be able to run mpirun on the instance-1.

1. Run scp <USER> <USER>@<EXTERNAL_IP_OF_FIRST_INSANCE>:/home/<USER>/.ssh .
2. Rename key to id_rsa. Run mv .ssh/<USER> .ssh/id_rsa.
3. To verify that everything works run ssh <INTERNAL_IP_OF_SECOND_INSTANCE>.
4. You should see welcome message.

Create HOSTFILE

We need to provide IP addresses to MPI.

1. Create hostfile on instance-1. Run touch hostfile.
2. Run echo <INTERNAL_IP_OF_THE_INSTANCE> >> hostfile for each machine in the cluster.

Run MPI

Now you can run your program on the cluster.

mpirun -np <NUMBER_OF_PROCESSES> --hostfile <HOSTFILE_NAME> ./<APPLICATION>