You need to enable the SSH Server to be able to login remotely without password. In my configuration, I want to be able to shutdown EFW remotely.
run ssh-keygen on apollo
copy the id_rsa.pub file to a USB stick, then attach the stick to avernus (vm)
copy apollo's id_rsa.pub file to /root/.ssh/authorized_keys
in avernus' web interface, set Allow public key based authentication only in SSH access in Menu System