CentOS and RHEL 8 or later versions
For CentOS and RHEL 8 or later versions, the dnf-automatic package is the preferred approach:
dnf install dnf-automatic
In /etc/dnf/automatic.conf set:
download_updates = yes
apply_updates = yes
Enable and start automatic updates via:
systemctl enable --now dnf-automatic.timer
Check status of dnf-automatic:
systemctl list-timers *dnf-*
CentOS and RHEL 7 or earlier versions
For CentOS and RHEL 7 or earlier versions, the yum-cron package is the preferred approach:
yum install yum-cron
In /etc/yum/yum-cron.conf set:
download_updates = yes
apply_updates = yes
Enable and start automatic updates via:
systemctl start yum-cron.service
openSUSE
First, you need to install the automatic update package
zypper install yast2-online-update-configuration
Then start the configuration tool (ncurses based) with:
yast2 online_update_configuration
Enable the following settings:
Automatic Online Update
Interval: Daily
Skip Interactive Patches
Agree with Licenses
Use delta rpms
Confirm your configuration with OK.
The official openSUSE documentation can be found here.