Suddenly systemctl stopped to work while I ssh'ed in my remote server to check service status. Output was
Failed to list units: Launch helper exited with unknown return code 1
I discovered that now upstart is used (after a couple of reboots trying to make systemctl work).
Can I use systemd as my main init again? I didn't found any info how to switch from upstart to systemd here.
Ubuntu 16.04.5.