Chapter 10 references old Ubuntu repos.

[kevinbowen777]

In the section Automating updates for Debian-based systems, Page 291:

1 # File: /etc/apt/apt.conf.d/50unattended-upgrades
2 Unattended-Upgrade::Automatic-Reboot "false";
3
4 Unattended-Upgrade::Allowed-Origins {
5 "Ubuntu lucid-security";
6 // "Ubuntu lucid-updates";
7 };

Lucid is Ubuntu's 10.04 release. For 18.04, this should be replaced with bionic.

[geerlingguy]

Yikes, you're right. I must've written that example a very long time ago.

The latest version has placeholders so it should be like:

# File: /etc/apt/apt.conf.d/50unattended-upgrades
Unattended-Upgrade::Automatic-Reboot "false";

Unattended-Upgrade::DevRelease "false";

Unattended-Upgrade::Allowed-Origins {
        "${distro_id}:${distro_codename}";
        "${distro_id}:${distro_codename}-security";
        "${distro_id}ESM:${distro_codename}";
//      "${distro_id}:${distro_codename}-updates";
//      "${distro_id}:${distro_codename}-proposed";
//      "${distro_id}:${distro_codename}-backports";
};

[geerlingguy]

This has been fixed in the book (as well as the RHEL section which needed to note that it's dnf-automatic in RHEL 8 instead of yum-cron). It will be in the next batch of updates. Thanks!