Get Emailed When an Ubuntu Server Needs a Reboot

When your Ubuntu server needs to be rebooted, say after a kernel update, the file /var/run/reboot-required is created. You can check for that file to see if a reboot is needed and usually you’ll get a message upon logging into the server saying so. Here’s how you can get an email when a reboot is needed saving you the time of manually checking.

Make sure the mailutils package is installed. You can accept all the default options:

sudo apt-get update && sudo apt-get install mailutils

Create the following file /etc/cron.daily/reboot-check:

#!/usr/bin/env bash

if [ -f /var/run/reboot-required ]; then
	echo "A reboot is required following updates to server <hostname>" | mail -s "Reboot Required" <email-address>
fi

Replace <hostname> with whatever you call your server and <email-address> that you want the email to go to.

Make sure the file is has the right ownership and permissions:

sudo chown root:root /etc/cron.daily/reboot-check
sudo chmod 755 /etc/cron.daily/reboot-check

Once a day the script will check if a reboot is required and email you if it is. Be sure to check your spam folder.

You can move this file from cron.daily to another directly such as cron.weekly to change the frequency.