Configuring the parallel engine to use the secure shell (ssh) program (AIX® Linux®)

The secure shell (ssh) program provides strong authentication and secure communications between computers on a network.

Before you begin

Ensure that ssh servers are installed on all of the computers where the parallel engine runs.

About this task

When you configure ssh to work with the parallel engine, the engine connects from the conductor node to all of the compute nodes, using RSA public key encryption for authentication. To set up ssh, do the following task for each user that runs parallel jobs. It is also necessary to log in to each computer before it can run parallel jobs.

Procedure

On the conductor node, run the following command to create public and private encryption keys. Press the Enter key twice when you run the command.
```
ssh-keygen -b 1024 -t rsa -f ~/.ssh/id_rsa
```
The keys are saved in the ~/.ssh/id_rsa directory.
If the user home directories are not automatically mounted, run the following commands to send the public key to the other computers.
Run scp for each user on each compute node.
```
cd ~/.ssh 
scp id_rsa.pub user@secondary_computer:~/.ssh 
```
Log in to each of the compute nodes and add the public key to the list of authorized keys.
Repeat this process for each user that runs parallel jobs.
```
cd .ssh 
cat id_rsa.pub >> authorized_keys2
chmod 640 authorized_keys2
rm -f id_rsa.pub
```
The file that contains the authorized keys might be named authorized_keys or authorized_keys2, depending on the version of ssh.
On the conductor node, run the following command for each user and compute node to test the ssh configuration:
```
 conductor_node_name% ssh computer_node_name ls
```
If the command is successful, you should be able to log in to the remote shell without providing a password.
On the conductor node, create the remsh file in the /Server/PXEngine/etc/ directory. In the file, specify the following content:
```
#!/bin/sh
exec /usr/bin/ssh "$@"
```
The /Server/PXEngine/etc/ directory is located in the directory where you installed the engine. The default directory is /opt/IBM/InformationServer/Server/PXEngine/.
Give the file execute permission:
```
chmod 755 remsh
```