Find out why your ubuntu stuck on reboot

Let's show detail logs when we were rebooting

1. edit /etc/default/grub, change the line GRUB_CMDLINE_LINUX_DEFAULT="quiet" to GRUB_CMDLINE_LINUX_DEFAULT="splash"

   quiet: this option tells the kernel to NOT produce any output. (If you add this, you'll see a screen of printed messages)

   splash: this option is used to start an eye-candy "loading" screen while all the core parts of the system are loaded in the background.

2. run update-grub2 or update-grub to reload the config

Can we just temporarily solve this problem?

1. edit /etc/systemd/system.conf
2. change a few lines of old config to: DefaultTimeoutStartSec=5s DefaultTimeoutStopSec=5s
3. run sudo systemctl daemon-reload