How to do an Apache Graceful Restart in CentOS 7
Apache Graceful Restart means, reloading the Apache Configuration(httpd.conf) without restarting the Web Server. When we do the Graceful Restart it only reloading the Configuration file and do not restart the Apache Web Server. So the currently open connections will not be aborted. So you can make the changes to the httpd.conf file and reload the changes without closing existing connection.
In CentOS 7 we can do a Apache Graceful Restart using either apachectl or systemctl command.
With apachectl command
apachectl graceful
Using systemctl Command
systemctl reload httpd.service
Anyway, If you Want to restart your http web server type
systemctl restart httpd.service