dnf-automatic-restart

dnf-automatic provides
automatic updates for your Linux server. However, once updates are applied, you
may need to restart services or even the machine (if the Linux kernel was
updated) to actually run updated components.

How it works

dnf-automatic-restart is a script to hook into the dnf-automatic update
process. After dnf-automatic-install.service finishes dnf-automatic-restart
is started and will:

• Check if tracer detected a kernel update and
  reboot the machine if a newer installed kernel is found,
• Check if systemd or
  auditd was updated and reboot the system,
• Use tracer to inspect which services need to be
  restarted and restart them.

Automatic reboots may be prevented or scheduled by specifying
options.

Installation

1. Clone this repository to a location of your choice. I'm using
   /usr/local/src/dnf-automatic-restart.

   cd /usr/local/src
   git clone https://github.com/agross/dnf-automatic-restart.git
   ln -s /usr/local/src/dnf-automatic-restart/dnf-automatic-restart /usr/local/sbin/dnf-automatic-restart

2. Install
   DNF tracer plugin
   which also installs tracer.

   dnf install -y dnf-plugins-extras-tracer

   On CentOS8 / Rocky8 / AlmaLinux the package is named python3-tracer

   dnf install -y python3-tracer

3. Install dnf-automatic and enable it.

   dnf install -y dnf-automatic
   # Edit /etc/dnf/automatic.conf.
   systemctl enable dnf-automatic-install.timer

4. Add a systemd drop-in for dnf-automatic-install.service. The drop-in will
   enhance the dnf-automatic-install.service unit to run
   dnf-automatic-restart after the update process has finished.

   SYSTEMD_EDITOR=tee systemctl edit dnf-automatic-install.service <<EOF
   [Service]
   # Path to the cloned script (see step 1 above).
   ExecStartPost=/usr/local/sbin/dnf-automatic-restart
   EOF

Options

You might want to configure times when automatic restarts are allowed or
scheduled.

For example, if you run dnf-automatic on your router and that router is also
required for telephony (e.g. VoIP), you might want to delay reboots until the
chances that someone is currently on the phone while your internet connection is
offline are small.

dnf-automatic-restart supports the following options:

-d        disable reboot
-h        display this help and exit
-n HOURS  no automatic reboot between hours (e.g. 8-22)
-r HOUR   schedule automatic reboot at hour (e.g. 0)

Use them as appropriate for your environment, for example:

[Service]
# Always schedule reboots at 00:00.
ExecStartPost=/usr/local/sbin/dnf-automatic-restart -r 0

[Service]
# No reboots between 08:00 and 22:59. You will need to reboot manually.
ExecStartPost=/usr/local/sbin/dnf-automatic-restart -n 8-22

[Service]
# No reboots between 08:00 and 22:59, schedule them for 00:00.
# If dnf-automatic runs at night (23:00-07:59), reboot immediately.
ExecStartPost=/usr/local/sbin/dnf-automatic-restart -n 8-22 -r 0

[Service]
# No reboots between 08:00 and 02:59, schedule them for 05:00.
# If dnf-automatic runs in the early morning (03:00-07:59), reboot immediately.
ExecStartPost=/usr/local/sbin/dnf-automatic-restart -n 8-2 -r 5

[Service]
# No automatic reboots, only services are restarted.
ExecStartPost=/usr/local/sbin/dnf-automatic-restart -d

Monitoring

dnf-automatic-restart logs its actions and the output of tracer to the
system journal. You can use this command to inspect actions taken:

journalctl --unit dnf-automatic-install.service

You also may run dnf-automatic-restart manually. Log entries are then also
printed to the terminal.