Is installing a GUI on my CentOS server a good idea?

Solution 1:

From a security point of view, installing a GUI is a bad idea as it greatly expands the attack surface of the host. Certainly a GUI does take up some resources which could otherwise be used by the VM's. Gnome will take up resources whenever it is running - regardless of whether or not you are using it.

The solution I typically use is to NOT install a GUI on the server, but install the minimal requirements (xauth package), access the machine via SSH and then run virt-manager through SSH such that it exports onto my workstation. The added benefit being I can do this from anywhere (and I can enable compression on SSH for slower connections as well)