How can I tell what package requires a reboot of my system?

Question

I have unattended-upgrade set up on my Ubuntu systems. Occasionally I will log in remotely to one of them and I'll see a message informing me that I need to reboot the system (in order to complete an upgrade). Is there a way to determine the specific package (or set of packages) which is triggering this notice?

Answer 1

Looks like there is an easy way to automatically extract the requested information.

Inside .deb files there are control files for installation, including postinst (run after installation).

For example, in linux-image-2.6.35-25-generic_2.6.35-25.44_amd64.deb,
postinst includes

my $notifier          = "/usr/share/update-notifier/notify-reboot-required";

my $warn_reboot     = 'Yes';     # Warn that we are installing a version of
                                 # the kernel we are running

and

# Warn of a reboot
if (-x $notifier) {
 system($notifier);
}

---

The shell script /usr/share/update-notifier/notify-reboot-required updates
/var/run/reboot-required and /var/run/reboot-required.pkgs.

The latter file contains a list of packages requesting a reboot.

Answer 2

Reboot is recommended by the unattended-upgrades when it sees that a /var/run/reboot-required exists. The file is created by postinst (post-installation) scripts in some packages, it looks something like this:

[ -x /usr/share/update-notifier/notify-reboot-required ] && \
/usr/share/update-notifier/notify-reboot-required || true

If you want to see which packages triggered this, you can have a look at the contents of the /var/run/reboot-required.pkgs file.

For more info also see this thread.

Answer 3

I don't really know if there are other packages that require rebooting, but kernel updates always do. I'd say almost every time I've been "asked" to reboot, the kernel had been updated.