Start OpenSSH sshd automatically on the BeagleBone Black

Question

Does anybody know how to start sshd automatically on the BeagleBone Black ? I've replaced dropbear with OpenSSH. The standard systemctl enable sshd doesn't work, but strangely systemctl start sshd does. I'm quite new to systems with systemd replacing init, so hopefully I'm not just missing something trivial / simple. The BeagleBone Black in question is running Angstrom Linux and is using the opkg package manager. OpenSSH was installed with opkg install openssh. When I run systemctl enable sshd@.service, I get the following message:

The unit files have no [Install] section. They are not meant to be enabled      
using systemctl.                                                                
Possible reasons for having this kind of units are:                             
1) A unit may be statically enabled by being symlinked from another unit's      
   .wants/ or .requires/ directory.                                             
2) A unit's purpose may be to act as a helper for some other unit which has     
   a requirement dependency on it.                                              
3) A unit may be started when needed via activation (socket, path, timer,       
   D-Bus, udev, scripted systemctl call, ...).                                  

The version I have installed is OpenSSH_6.0p1, OpenSSL 1.0.1e 11 Feb 2013

Answer 1

Apparently systemd has both an sshd.service unit and an sshd.socket unit, that are intended to be used mutually exclusively of each other. The sshd daemon should be started and connected automatically by systemd every time an outside process connects to port 22.