Yum-cron settings for CentOS 7

1. Make sure postfix is installed, autostarting and started.
2. Install yum-cron.
   1. # yum install yum-cron
3. Set autostart daemon.
   1. # systemctl enable yum-cron.service
4. Start the daemon.
   1. # systemctl start yum-cron.service
   2. # systemctl status yum-cron.service
5. Edit /etc/yum/yum-cron.conf.
6. Check and change as appropriate the following lines:
   1. update_cmd = default
   2. update_messages = yes
   3. download_updates = yes
   4. apply_updates = no
   5. random_sleep = 0
   6. emit_via = email
   7. email_from = root@localhost>
   8. email_to = This email address is being protected from spambots. You need JavaScript enabled to view it.
   9. email_host = smtp.uu.se
7. Restart the daemon for good measure.
   1. # systemctl stop yum-cron.service
   2. # systemctl start yum-cron.service
8. Done.

Source: https://linuxaria.com/howto/enabling-automatic-updates-in-centos-7-and-rhel-7

Alse see Nightly linux updates doesn't work, Yum-cron settings for CentOS 6.