Open Stack

I'm setting up another test installation. I'm working on Ubuntu with
Havana using http://docs.openstack.org/havana/install-guide/install/apt/content/.

According to the OpenStack Installation Guide, the example uses a
Controller with Keystone, Glance and Nova. Freat job on those
documents, btw. (See http://postimg.org/image/ct3i150qr/ for a screen
capture of the page with a logical diagram).

I want to move Keystone to its own virtual machine for segregation
(this will eventually be a security requirement). I also want to move
Nova to its own VM (in addition to one VM for a Swift node).

What are the minimum components required for the controller? Does that
leave Glance, MySQL and RabbitMQ? Can Glance be moved somewhere if
desired (or must it remain on the controller)?

Sorry about the basic question. I'm still working though examples to
see what works, what does not, and how I manage to break things ;)

Thanks in advance.