Ubuntu – Reboot a Server from Command Line

Who knows when/if this problem: "systemd-shutdown: Failed to finalize DM devices. ignoring." will ever be fixed on this old platform - nothing I've read would suggest it'll be anytime soon.

In the meantime, this work-around allows me to reboot my server without physically power cycling the machine.

All the following commands are under sudo:

• Put these commands into a file such as ~/sysrq-reboot.sh
  echo 1 > /proc/sys/kernel/sysrq sync && echo b > /proc/sysrq-trigger
• chmod +x the file to make it executable
• then, to reboot just run the script with sudo ~/sysrq-reboot.sh

If running the script remotely via ssh, I find I also need to hard close my ssh window and re-establish a new ssh session (after waiting a minute for the machine to become reachable).

OK. The first problem (reboot problem after installation was completed) occurred because I set acpi=off during the installation because Ubuntu got stuck in loading purple screen. After many tries I could pass by the purple screen by chance without setting acpi=off! Then after installation, Ubuntu was restarted without any problem.

The second problem (shutdown and restart problem after Ubuntu was booted for the first time from hard disk) was because of Nvidia driver. I did

sudo apt-get update
sudo apt-get upgrade
sudo apt-get dist-upgrade
sudo ubuntu-drivers devices
sudo apt-get install nvidia-361

And now everything is fine :-)

UPDATE

As I said I could not pass by the purple screen during the installation and I found what the problem was. I had connected a USB 2.0 flash drive to a USB 3.0 port for installing Ubuntu. Today I connected a USB 3.0 flash drive to the USB 3.0 port and I booted Ubuntu with that and the problem was solved (I don't need to wait for a chance or set acpi=off to boot Ubuntu). But unfortunately I am getting a new problem and it is I cannot reboot or shutdown Ubuntu .