After a recent update to a VPS server I have running Ubuntu 16.04, I found that
sshd was not starting automatically on boot.
The error in syslog was:
sshd: Missing privilege separation directory: /var/run/sshd
systemd: ssh.service: Control process exited, code=exited status=255
After a bit of investigation (and looking at Upstart scripts in
/etc/init which it turned out were not being used), I found that
sshd should have been started by the
systemd script in
I compared this script on my 16.04 machine to the same thing on another machine running 18.04, and I spotted that it was missing these two lines:
Adding them in, and it all now works.
No idea what update caused it all to stop working, though.