h1- host that will be doing the passwordless SSHing
h2- host that will be SSHd into
1. h1: (as root) cd /root/.ssh
2. h1: ssh-keygen, enter, enter, enter (use default filename and empty passphrase)
3. h1: ssh-copy-id -i ~/.ssh/id_rsa.pub username@h2
4. test SSHing from h1 to h2 -- shouldn't ask for password
