How to add a server to an existing web domain?

[Madman6510]

I have a website on a hosting server that I want to add some things to. Problem is, the server isn't ours, but rather a friends. The web app I want to run requires some programs to be installed and up to date, and also requires access to the MySQL database. Instead of asking him to update and install his software, and giving me the root password to the database, I would like to add my server to the domain, kind of like as a secondary server.

The server I am setting up runs Ubuntu, not sure about his.

EX:
Main server: www.example.com
Secondary: wiki.example.com

How would one do this?

[lykwydchykyn]

He just needs to add an entry for it in his DNS.