Sometimes, Ubuntu 18.04 system hangs or takes a very long time to shutdown.
supervisor process manager takes a long time to reboot ubuntu 18.04
We can fix this by editing the system.conf file.
Go here and edit. before edit take this file for backup.
$ sudo nano /etc/systemd/system.conf
uncomment the ChangeTimeoutStopSec=90s and Change the DefaultTimeoutStopSec section to around 4 or 5 seconds.
#DefaultTimeoutStopSec=90s DefaultTimeoutStopSec=4s
Save the file, and reboot. 🙂