Check services that are enabled on CentOS 7
# systemctl list-unit-files
Or for a specific service
# systemctl status mysqld
Disabling a service on boot in CentOS 7
To disable, it’s simply a matter of running systemctl disable on the desired service.
# systemctl disable mysqld
Check which services failed to start on boot on CentOS 7
As a bonus, systemctl allows you to list all services that failed to start on boot, even though they were configured to start on boot.
# systemctl --failed