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E. Diaz
Asked: 2015-08-14 10:51:44 +0800 CST

"System restart required"...why? How can I get what triggered this notification to also show details?

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Every so often, I'll SSH into a box with unattended-upgrades and be greeted with "** System restart required ***" with no additional information.

My '/var/run/reboot-required.pkgs' file contains:

linux-image-3.13.0-61-generic
linux-base
linux-base
linux-base

I don't mind rebooting, but I don't like rebooting without having details of WHY I should reboot in the first place. Above, I see two packages triggered the message, but there's no explanation beyond that.

Is there a way to get additional details about the reason for the reboot to also show up on SSH sign in?

Ideally, I would like to pull in a file that contains something human-readable like, "Package xyz was updated at [date/time]. It needed to modify files a, b, and c but could not because the system blocked/would block the action. During the next reboot, files a, b, and c will be replaced." But something not completely human-readable is probably okay too.

motd

2 Answers

  1. Edit: Another, probably relevant or useful article.

    As you already found out you can find the packages that require a restart in /var/run/reboot-required.pkgs

    Now you just need to look in the changelog of the package to find the information you are looking for.

    • If you are already on the machine you can find the changelogs in /usr/share/doc/${package_name} (example: zless /usr/share/doc/linux-image-3.13.0-61-generic/changelog.Debian.gz).
    • Debian provides some tools like apt-listchanges to make this more convenient (1, 2, 3).

    • Another way to do that would be to use packages.ubuntu.com.

      In your case:

      image showing where to find the link for the changelog on packages.ubuntu.com

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  2. The file ultimately called is /usr/lib/update-notifier/update-motd-reboot-required (it's called by /etc/update-motd.d/98-reboot-required).

    Inside the conditional if statement of one of those files, simply add this:

        echo "Packages causing reboot:"
    cat /var/run/reboot-required.pkgs

    So, for instance, your /usr/lib/update-notifier/update-motd-reboot-required file would look something like this:

    #!/bin/sh -e
#
# helper for update-motd

if [ -f /var/run/reboot-required ]; then
        cat /var/run/reboot-required
        echo "Packages causing reboot:"
        cat /var/run/reboot-required.pkgs
fi
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