Run the following command on your systems to generate SSH keys if they are not there in /root/.ssh
ssh-keygen -t rsa -b 1024
Once the keys are generated, copy the key of one system from /root/.ssh/id_rsa.pub and make a new file in the other system with the name authorized_keys. This file should be created in the /root/.ssh/ directory.
Repeat the same for the other system. You will be sharing ssh keys between 2 systems which will allow you a direct connection between both systems without any authentication or password prompt. Make sure that the SSH ports are set to the default (22) for both systems. If they are different then you will need to specify the ssh port in the connection string or the scripts that you will use to share files and folders.