1) SSH has to be enabled in both hosts. I will not detail this because it's well documented in installation guides.
2) Using vSphere client, go to "Configuration" tab for the host. Select "Security Profile" option on the left. Then "Properties" for the firewall section.
Check both SSH Server and SSH Client services.
3) Login to the console with root user:
ssh root@xxx.xxx.xxx.xxx
4) Verify that .ssh folder exists. If no, create it.
ls -la /.ssh
5) Create your private and public key
/usr/lib/vmware/openssh/bin/ssh-keygen -t dsa
When prompt for the name of the file in which to save the key, select: /.ssh/id_dsa
When prompt for passphrase, leave it empty (twice).
6) Now you have to export the public key from one host to the other and viceversa. The public key is a text file so you can cut and paste:
Copy the content of the file /.ssh/id_dsa.pub
and add it to the file /etc/ssh/keys-root/authorized_keys on the other host
I hope it will be usefull.