Chapter 2. Installing security updates
2.1. Installing all available security updates
To keep the security of your system up to date, you can install all currently available security updates using the dnf
utility.
Prerequisite
- A Red Hat subscription attached to the host.
Procedure
Install security updates using
dnf
utility:#
dnf update --security
NoteThe
--security
parameter is important. Without it,dnf update
installs all updates, including bug fixes and enhancements.Confirm and start the installation by pressing y:
... Transaction Summary =========================================== Upgrade ... Packages Total download size: ... M Is this ok [y/d/N]: y
Optional: list processes that require a manual restart of the system after installing the updated packages:
#
dnf needs-restarting
1107 : /usr/sbin/rsyslogd -n 1199 : -bashNoteThis command lists only processes that require a restart, and not services. That is, you cannot restart processes listed using the
systemctl
utility. For example, thebash
process in the output is terminated when the user that owns this process logs out.
2.2. Installing a security update provided by a specific advisory
In certain situations, you might want to install only specific updates. For example, if a specific service can be updated without scheduling a downtime, you can install security updates for only this service, and install the remaining security updates later.
Prerequisites
- A Red Hat subscription attached to the host.
- You have the ID of the security advisory that you want to update. For more information, see identifying the security advisory updates.
Procedure
Install a specific advisory:
#
dnf update --advisory=<Update_ID>
Replace <Update_ID> with the ID of the security advisory that you want to update. For example:
# dnf update --advisory=RHSA-2019:0997
ImportantYou can update to apply a specific advisory with a minimal version change by using the
dnf upgrade-minimal --advisory=<Update_ID>
command.Confirm and start the installation by pressing
y
:... Transaction Summary =========================================== Upgrade ... Packages Total download size: ... M Is this ok [y/d/N]: y
Optional: List the processes that require a manual restart of the system after installing the updated packages:
#
dnf needs-restarting
1107 : /usr/sbin/rsyslogd -n 1199 : -bashNoteThis command lists only processes that require a restart, and not services. This means that you cannot restart all processes listed by using the
systemctl
utility. For example, thebash
process in the output is terminated when the user that owns this process logs out.
2.3. Installing security updates automatically
You can configure your system so that it automatically downloads and installs all security updates.
Prerequisites
- A Red Hat subscription attached to the host.
-
The
dnf-automatic
package is installed.
Procedure
In the
/etc/dnf/automatic.conf
file, under the[commands]
section, make sure theupgrade_type
option is set to eitherdefault
orsecurity
:[commands] # What kind of upgrade to perform: # default = all available upgrades # security = only the security upgrades upgrade_type = security
Enable and start the
systemd
timer unit:# systemctl enable --now dnf-automatic-install.timer
Verification
Verify that the timer is enabled:
# systemctl status dnf-automatic-install.timer
Additional resources
-
dnf-automatic(8)
man page
2.4. Additional resources
- See practices of securing workstations and servers in Security Hardening document.
- Security-Enhanced Linux documentation.