Apache monitoring is one of the simplest things to set up monitoring for as all that is required is a modification to the httpd.conf file to turn on the server-status page and allowing the device you wish to monitor from.

Doing that is fairly straightforward.
First thing to do is shutdown Apache with the command

This will stop Apache gracefully. Once you have run that command go to your Apache config directory. Mine is /etc/httpd/conf/
once inside there you’ll want to edit your httpd.conf using

once inside you’ll want to look for the line

You’ll want to un-comment that line (remove the #), then keep scrolling down looking for the something similar to these lines.

These may be commented out, so un-comment those and add the add the address of where you are monitoring from so it looks something like this.

Once thats done, write out the changes and close. You can then restart Apache using.

Then test by going to http://somedomain/server-status from the address you allowed and you should see a server status page.