Configure Unattended-Upgrades

In order for unattended-updates to work seamlessly, you can add the following lines in. This will allow updates from all repositories, remove unused kernel related packages, remove unused dependencies, and automaticaly reboot the system if required.

Install Unattended-Upgrades:

sudo apt install unattended-upgrades -y

Modify the Unattended-Upgrades config file:

sudo nano /etc/apt/apt.conf.d/50unattended-upgrades

Within the file change the following attributes:

Apply updates from all repositories:

Unattended-Upgrade::Origins-Pattern {
        "origin=*";
};

Remove unused dependencies:

// Do automatic removal of new unused dependencies after the upgrade
// (equivalent to apt-get autoremove)
Unattended-Upgrade::Remove-Unused-Dependencies "true";

Remove unused kernel related packages:

// Remove unused automatically installed kernel-related packages
// (kernel images, kernel headers and kernel version locked tools).
Unattended-Upgrade::Remove-Unused-Kernel-Packages "true";

Automatically reboot after upgrades when required at a specific time, but not if users are logged in:

// Automatically reboot *WITHOUT CONFIRMATION*
//  if the file /var/run/reboot-required is found after the upgrade
Unattended-Upgrade::Automatic-Reboot "true";

// If automatic reboot is enabled and needed, reboot at the specific
// time instead of immediately
//  Default: "now"
Unattended-Upgrade::Automatic-Reboot-Time "06:00";

// Automatically reboot even if users are logged in
Unattended-Upgrade::Automatic-Reboot-WithUsers "false";

Here is the complete file with all the changes:

// Unattended-Upgrade::Origins-Pattern controls which packages are
// upgraded.
//
// Lines below have the format "keyword=value,...".  A
// package will be upgraded only if the values in its metadata match
// all the supplied keywords in a line.  (In other words, omitted
// keywords are wild cards.) The keywords originate from the Release
// file, but several aliases are accepted.  The accepted keywords are:
//   a,archive,suite (eg, "stable")
//   c,component     (eg, "main", "contrib", "non-free")
//   l,label         (eg, "Debian", "Debian-Security")
//   o,origin        (eg, "Debian", "Unofficial Multimedia Packages")
//   n,codename      (eg, "jessie", "jessie-updates")
//     site          (eg, "http.debian.net")
// The available values on the system are printed by the command
// "apt-cache policy", and can be debugged by running
// "unattended-upgrades -d" and looking at the log file.
//
// Within lines unattended-upgrades allows 2 macros whose values are
// derived from /etc/debian_version:
//   ${distro_id}            Installed origin.
//   ${distro_codename}      Installed codename (eg, "buster")

Unattended-Upgrade::Origins-Pattern {
        "origin=*";
};

// Python regular expressions, matching packages to exclude from upgrading
Unattended-Upgrade::Package-Blacklist {
    // The following matches all packages starting with linux-
//  "linux-";

    // Use $ to explicitely define the end of a package name. Without
    // the $, "libc6" would match all of them.
//  "libc6$";
//  "libc6-dev$";
//  "libc6-i686$";

    // Special characters need escaping
//  "libstdc\+\+6$";

    // The following matches packages like xen-system-amd64, xen-utils-4.1,
    // xenstore-utils and libxenstore3.0
//  "(lib)?xen(store)?";

    // For more information about Python regular expressions, see
    // https://docs.python.org/3/howto/regex.html
};

// This option allows you to control if on a unclean dpkg exit
// unattended-upgrades will automatically run 
//   dpkg --force-confold --configure -a
// The default is true, to ensure updates keep getting installed
//Unattended-Upgrade::AutoFixInterruptedDpkg "true";

// Split the upgrade into the smallest possible chunks so that
// they can be interrupted with SIGTERM. This makes the upgrade
// a bit slower but it has the benefit that shutdown while a upgrade
// is running is possible (with a small delay)
//Unattended-Upgrade::MinimalSteps "true";

// Install all updates when the machine is shutting down
// instead of doing it in the background while the machine is running.
// This will (obviously) make shutdown slower.
// Unattended-upgrades increases logind's InhibitDelayMaxSec to 30s.
// This allows more time for unattended-upgrades to shut down gracefully
// or even install a few packages in InstallOnShutdown mode, but is still a
// big step back from the 30 minutes allowed for InstallOnShutdown previously.
// Users enabling InstallOnShutdown mode are advised to increase
// InhibitDelayMaxSec even further, possibly to 30 minutes.
//Unattended-Upgrade::InstallOnShutdown "false";

// Send email to this address for problems or packages upgrades
// If empty or unset then no email is sent, make sure that you
// have a working mail setup on your system. A package that provides
// 'mailx' must be installed. E.g. "[email protected]"
//Unattended-Upgrade::Mail "";

// Set this value to one of:
//    "always", "only-on-error" or "on-change"
// If this is not set, then any legacy MailOnlyOnError (boolean) value
// is used to chose between "only-on-error" and "on-change"
//Unattended-Upgrade::MailReport "on-change";

// Remove unused automatically installed kernel-related packages
// (kernel images, kernel headers and kernel version locked tools).
Unattended-Upgrade::Remove-Unused-Kernel-Packages "true";

// Do automatic removal of newly unused dependencies after the upgrade
//Unattended-Upgrade::Remove-New-Unused-Dependencies "true";

// Do automatic removal of unused packages after the upgrade
// (equivalent to apt-get autoremove)
Unattended-Upgrade::Remove-Unused-Dependencies "true";

// Automatically reboot *WITHOUT CONFIRMATION* if
//  the file /var/run/reboot-required is found after the upgrade
Unattended-Upgrade::Automatic-Reboot "true";

// Automatically reboot even if there are users currently logged in
// when Unattended-Upgrade::Automatic-Reboot is set to true
//Unattended-Upgrade::Automatic-Reboot-WithUsers "true";

// If automatic reboot is enabled and needed, reboot at the specific
// time instead of immediately
//  Default: "now"
Unattended-Upgrade::Automatic-Reboot-Time "06:00";

// Use apt bandwidth limit feature, this example limits the download
// speed to 70kb/sec
//Acquire::http::Dl-Limit "70";

// Enable logging to syslog. Default is False
// Unattended-Upgrade::SyslogEnable "false";

// Specify syslog facility. Default is daemon
// Unattended-Upgrade::SyslogFacility "daemon";

// Download and install upgrades only on AC power
// (i.e. skip or gracefully stop updates on battery)
// Unattended-Upgrade::OnlyOnACPower "true";

// Download and install upgrades only on non-metered connection
// (i.e. skip or gracefully stop updates on a metered connection)
// Unattended-Upgrade::Skip-Updates-On-Metered-Connections "true";

// Verbose logging
// Unattended-Upgrade::Verbose "false";

// Print debugging information both in unattended-upgrades and
// in unattended-upgrade-shutdown
// Unattended-Upgrade::Debug "false";

// Allow package downgrade if Pin-Priority exceeds 1000
// Unattended-Upgrade::Allow-downgrade "false";

// When APT fails to mark a package to be upgraded or installed try adjusting
// candidates of related packages to help APT's resolver in finding a solution
// where the package can be upgraded or installed.
// This is a workaround until APT's resolver is fixed to always find a
// solution if it exists. (See Debian bug #711128.)
// The fallback is enabled by default, except on Debian's sid release because
// uninstallable packages are frequent there.
// Disabling the fallback speeds up unattended-upgrades when there are
// uninstallable packages at the expense of rarely keeping back packages which
// could be upgraded or installed.
// Unattended-Upgrade::Allow-APT-Mark-Fallback "true";

When you have edited and saved the changes to 50unattended-upgrades, you can run the following command to test that the unattended upgrades config works:

sudo unattended-upgrade