[NTLUG:Discuss] Web-server Farm - Networking Question

[Chris Cox]

David Simmons wrote:
> 
> I know what I'm hoping to do....I need help in understanding which
> technology/buzz-word to research and RTFineM on.
> 
> Situation:
> 
> Physical CentOS server with a single, static IP address....with
> multiple virtual machines - each VM (also linux / CentOS based) set up for
> web-hosting (LAMP with ssh/ftp access).  Say VM1 hosts
> www.somesite.com.....say VM2 hosts www.anothersite.com.....and say VM3
> hosts www.finalsite.com
> 
> I'd like to setup DNS to point to the
> single 'real-world' address - but have the individual VM respond to the
> request.
> 
> What technology do I use so that all of the virtual
> machines are seen on the 'real' static IP address to the world?.....so
> that people on the internet can SSH into their own box (which is just a VM
> on the host).
> 
> I've been researching Multi-homing.....and Linux
> Virtual Server.....but some of the howto's/docs are ancient.
> 
> Any book / site / howto suggestions?

There are ways of handling web of course, but many protocols
don't really care about the name so much as the IP, and since
they would all have the same IP, most services couldn't be
made to be 'specific' to one VM or another.

You could run services on different port numbers though.  But
that might be too difficult (?).

Perhaps another possibility is some kind of tunneling to each
VM.  That would reduce the number of differing ports, you just
have to pick the right initial port to create a VPN to the VM
you're wanting.  With all of the limitations and major security
risks that come with VPN naturally.