I've just updated my Ubuntu 16 to 18.04.1 LTS, upon restart it fails to boot (completely unresponsive). I've tried booting in safe mode and works but I see there is an error on the cgmanager, specifically:
Failed to start Cgroup management daemon. See 'systemctl status cgmanager.service' for details.
Restarting doesn't seem to work. When I checked the cgmanager log (at upstart), the only message I see is:
initctl: Method "NotifyCGroupManagerAddress" with signature "s" on interface "com.ubuntu.Upstart0_6" doesn't exist
I'm not familiar with the upstart process, so my first guess would be that cgmanager failed to be updated with the rest of the packages. I'd like an expert's opinion before venturing there.
Best Answer
What I found is that the cgmanager package no longer exists in 18.04 (the search https://packages.ubuntu.com/search?searchon=contents&keywords=cgmanager&mode=exactfilename&suite=bionic&arch=any returns an empty result) But the package does not get removed during the upgrade, which is strange.