Most of the reverse proxies are nowadays implemented using Apache. Apache, other than being a web server, is quite useful as a reverse proxy as it includes some powerful modules:

Other than as a reverse proxy, it can be used as a load balancer thanks to:

Now, unfortunately, there isn't a valid method to acquire the metrics strictly related to the module used, but anyway, we can acquire quite a few metrics from Apache itself.

The first thing you have to do before you can acquire the statistics is enable them. To do this, you need to put the following lines in your Apache configuration file:

<Location /server-status>
  SetHandler server-status
  Allow from 127.0.0.1 
  Order deny,allow
  Deny from all
</Location>

Also, you can optionally add the following line to your global Apache configuration file:

 ExtendedStatus On

Here, we are configuring the module with the ExtendedStatus On option. With this setting...