**System restart required**

This is a message which i get regular after updating my (ubuntu) linux server(s) and logging in later..

Quiet annoying for me, mostly when i login, i do not want the reboot the server, because it is in production. Even that the reboot time is short, i dont want to disrupt the processes.. So i wanted to scheduled the reboot when needed, instead of logging in on free hours. Actually that was quiet easy..

Step one:

Create a script that does trigger a restart when needed. But how do you check that? Actually very easy; when the file “/var/run/reboot-required” exists, you need to restart. So i created the following script: “reboot-when-required.sh”

#!/bin/bash
# To reboot @night add in root crontab:
# eg: sudo crontab -e:
#	#Reboot when needed
#	0 4 * * * /home/<name>/bin/reboot-when-required.sh
#

if [ -f /var/run/reboot-required ]; then
  echo "$(date +'%y%m%d %H:%M:%S') Reboot required; rebooting.." >> /home/<name>/bin/logs/reboot-required.log
  /sbin/reboot
fi

This script is installed in de /home/<name>/bin folder, and a logs folder should also be created. It does the following:

1. Check if file /var/run/reboot-required exists; when found:
   • Add a line to the logging file
   • Reboot the computer

Step two:

You need to add the following line(s) into the root crontab, als elevated rights are required:

#Reboot when needed
5 4 * * * /home/<name>/bin/reboot-when-required.sh

In the example this script is run daily @4:05 AM. You can change that to your requirements.