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

  1. Install security updates using dnf utility:

    # dnf update --security
    Note

    The --security parameter is important. Without it, dnf update installs all updates, including bug fixes and enhancements.

  2. Confirm and start the installation by pressing y:

    ...
    Transaction Summary
    ===========================================
    Upgrade  ... Packages
    
    Total download size: ... M
    Is this ok [y/d/N]: y
  3. 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 : -bash
    Note

    This command lists only processes that require a restart, and not services. That is, you cannot restart processes listed using the systemctl utility. For example, the bash 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

Procedure

  1. 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
    Important

    You can update to apply a specific advisory with a minimal version change by using the dnf upgrade-minimal --advisory=<Update_ID> command.

  2. Confirm and start the installation by pressing y:

    ...
    Transaction Summary
    ===========================================
    Upgrade  ... Packages
    
    Total download size: ... M
    Is this ok [y/d/N]: y
  3. 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 : -bash
    Note

    This 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, the bash 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

  1. In the /etc/dnf/automatic.conf file, under the [commands] section, make sure the upgrade_type option is set to either default or security:

    [commands]
    #  What kind of upgrade to perform:
    # default                            = all available upgrades
    # security                           = only the security upgrades
    upgrade_type = security
  2. Enable and start the systemd timer unit:

    # systemctl enable --now dnf-automatic-install.timer

Verification

  1. Verify that the timer is enabled:

    # systemctl status dnf-automatic-install.timer

Additional resources

  • dnf-automatic(8) man page

2.4. Additional resources