Generates key on source machine
===
ssh-keygen -t rsa -C root@source_hostname.domain.org

Copies key to target machine
===
ssh-copy-id root@target_hostname.domain.org

SSH into target machine
===
ssh root@target_hostname.domain.org

Copies keys to other servers in cluster
===
ssh-copy-id root@target2_hostname.domain.org
ssh-copy-id root@target3_hostname.domain.org
ssh-copy-id root@target4_hostname.domain.org

Troubleshooting
===
chmod 777 /root/.ssh - may fix password prompts after copying key to target server
DO NOT chmod g-w /root/.ssh - Jenkins builds will get "Permission Denied" errors and fail