There were cases when it was urgent to turn off some Linux Ubuntu servers using the Power button, but when it was pressed, nothing happened. And to go over SSH and enter the poweroff or shutdown commands, the option is not optimal. So the solution to this inconvenience is to install ACPID (Power Management Services):
sudo apt-get install acpid
After installation of which a standard configuration file is created and a sh script that is executed when the Power button is pressed and correctly shuts down the system.