I have a CentOS box that runs a few headless VBox VM's. I use them for development / testing before pushing changes live. I have one of them setup pretty much

I have a CentOS box that runs a few headless VBox VM's. I use them for development / testing before pushing changes live. I have one of them setup pretty much exactly like our production server. I do all of that work over ssh. None of the VMs have an X window system installed.