Retrospective #1 – VirtualHosts in Apache

Retrospective #1 – VirtualHosts in Apache

Lately, I have been interested in monitoring my VMs and looking at pretty graphs with statistics on how a machine is performing. I came across a pretty sweet tool called net-data, which provides real-time data on performance and health monitoring. The only problem I have with net-data is that the web portion of net-data is served on port 19999, which is an ugly number and being the nit-pick that I am seeing it in the address bar is pain.

To remedy this, I decided to find a way to ‘serve’ the net-data web ui to a sub-domain instead.

So this is how I originally envisioned the set-up would work:

  1. Set-up a sub-domain such as
  2. When I visit the above sub-domain, it will serve the net-data web ui that is located at
  3. I did not want this to be a re-direct, I want to preserve the domain in my address bar.

The best solution I found for this was to use Apache and define a VirtualHost for my sub-domain. Essentially, the set-up is to leverage mod_proxy in Apache and set-up a reverse proxy so that, will serve the web ui located at port 19999

How was this done

First, I created a conf file in /etc/httpd/conf.d for my sub-domain:
$ vim /etc/httpd/conf.d/

I believe the ‘CentOS’ standard is to place any additional conf files in conf.d whereas Debian/Ubuntu, virtualhosts can be added straight to the main conf file. I could be wrong though.

In the conf file, the following settings will result in the sub-domain serving the web page on a desired port. I am using a reverse proxy to achieve this:

ProxyRequests Off
ProxyPreserveHost On

<Proxy *>
Require user kelvin
Order deny,allow
Allow from all

ProxyPass / http://localhost:19999/
ProxyPassReverse / http://localhost:19999/

Some notes:

  1. ProxyPreserveHost keeps the sub-domain the address bar. This is to prevent having the actual address from being exposed  (aka http://localhost:19999/)
  2. ProxyRequests Off – If this is set to ‘On’, your Apache server basically operates as a open proxy server, which is dangerous. The setting should only be ‘On’ if you have confidently secured your server. As well from the Apache website:

The ProxyRequests directive should usually be set off when using ProxyPass.


After adding the configuration and restarting Apache, visiting the sub-domain should now serve the web page hosted at the specified port.

Lessons Learned

Usually I like to add a ‘lessons learned’ section to kind of go over what I learned from the process. What have I learned from this exercise?


Why? Cause the creator added a handy wiki page that goes over everything I tried to do on my own.. Basically, what took a few hours could have taken a just a hour (or less).

The good thing is that I learned quite a bit about Apache.

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