Always remember to activate this package
apt-get/yum install unattended-upgrades
sudo dpkg-reconfigure --priority=low unattended-upgrades
cat /etc/apt/apt.conf.d/20auto-upgrades
should result in
APT::Periodic::Update-Package-Lists "1";
APT::Periodic::Unattended-Upgrade "1";
CentOS
$ sudo yum install yum-cron
## el6
$ cat /etc/sysconfig/yum-cron
CHECK_ONLY=no
DOWNLOAD_ONLY=no
$ service start yum-cron
$ chkconfig yum-cron on
## el7
$ cat /etc/yum/yum-cron.conf
download_updates = yes
apply_updates = yes
emit_via = stdio
$ systemctl start yum-cron.service
$ systemctl enable yum-cron.service
$ tail -f /var/log/yum.log
