CentOS 7下出现Warning: Unit file of mysql.service changed on disk, 'systemctl daemon-reload' recommended.错误，根据提示，
解决方法：
systemctl daemon-reload
CentOS 7下出现Warning: Unit file of mysql.service changed on disk, 'systemctl daemon-reload' recommended.错误，根据提示，
解决方法：
systemctl daemon-reload