Using unattended-upgrades on Rackspace's Debian and Ubuntu servers

I install the unattended-upgrades package on almost all of my Debian and Ubuntu servers in order to ensure that security updates are automatically applied. It works quite well except that I still need to login manually to upgrade my Rackspace servers whenever a new rackspace-monitoring-agent is released because it comes from a separate repository that's not covered by unattended-upgrades.

It turns out that unattended-upgrades can be configured to automatically upgrade packages outside of the standard security repositories but it's not very well documented and the few relevant answers you can find online are still using the old whitelist syntax.

Initial setup

The first thing to do is to install the package if it's not already done:

apt-get install unattended-upgrades

and to answer yes to the automatic stable update question.

If you don't see the question (because your debconf threshold is too low -- change it with dpkg-reconfigure debconf), you can always trigger the question manually:

dpkg-reconfigure -plow unattended-upgrades

Once you've got that installed, the configuration file you need to look at is /etc/apt/apt.conf.d/50unattended-upgrades.

Whitelist matching criteria

Looking at the unattended-upgrades source code, I found the list of things that can be used to match on in the whitelist:

origin (shortcut: o)
label (shortcut: l)
archive (shortcut: a)
suite (which is the same as archive)
component (shortcut: c)
site (no shortcut)

You can find the value for each of these fields in the appropriate _Release file under /var/lib/apt/lists/.

Note that the value of site is the hostname of the package repository, also present in the first part these *_Release filenames (stable.packages.cloudmonitoring.rackspace.com in the example below).

In my case, I was looking at the following inside /var/lib/apt/lists/stable.packages.cloudmonitoring.rackspace.com_debian-wheezy-x86%5f64_dists_cloudmonitoring_Release:

Origin: Rackspace
Codename: cloudmonitoring
Date: Fri, 23 Jan 2015 18:58:49 UTC
Architectures: i386 amd64
Components: main
...

which means that, in addition to site, the only things I could match on were origin and component since there are no Suite or Label fields in the Release file.

This is the line I ended up adding to my /etc/apt/apt.conf.d/50unattended-upgrades:

 Unattended-Upgrade::Origins-Pattern {
         // Archive or Suite based matching:
         // Note that this will silently match a different release after
         // migration to the specified archive (e.g. testing becomes the
         // new stable).
 //      "o=Debian,a=stable";
 //      "o=Debian,a=stable-updates";
 //      "o=Debian,a=proposed-updates";
         "origin=Debian,archive=stable,label=Debian-Security";
         "origin=Debian,archive=oldstable,label=Debian-Security";
+        "origin=Rackspace,component=main";
 };

Testing

To ensure that the config is right and that unattended-upgrades will pick up rackspace-monitoring-agent the next time it runs, I used:

unattended-upgrade --dry-run --debug

which should output something like this:

Initial blacklisted packages: 
Starting unattended upgrades script
Allowed origins are: ['origin=Debian,archive=stable,label=Debian-Security', 'origin=Debian,archive=oldstable,label=Debian-Security', 'origin=Rackspace,component=main']
Checking: rackspace-monitoring-agent (["<Origin component:'main' archive:'' origin:'Rackspace' label:'' site:'stable.packages.cloudmonitoring.rackspace.com' isTrusted:True>"])
pkgs that look like they should be upgraded: rackspace-monitoring-agent
...
Option --dry-run given, *not* performing real actions
Packages that are upgraded: rackspace-monitoring-agent

Making sure that automatic updates are happening

In order to make sure that all of this is working and that updates are actually happening, I always install apticron on all of the servers I maintain. It runs once a day and emails me a list of packages that need to be updated and it keeps doing that until the system is fully up-to-date.

The only thing missing from this is getting a reminder whenever a package update (usually the kernel) requires a reboot to take effect. That's where the reboot-notifier package comes in.

This assumes that you are already receiving emails sent to the root user (if not, add the appropriate alias in /etc/aliases and run newaliases).