technically, yes - although using it easily and "out of the box" with no twaeking might be troublesome. Adding a ganglia agent to each of your openstack compute nodes is where you'd want to start, and from there its very dependent on what openstack network configuration youre using and if multicast is directly viable between all your nodes.
That will give you the hypervisor host details. If you want the details of the VMs themselves, you're better using a plugin to get data from Libvirt (im assuming a KVM based openstack here, not the other hypervisors) for best/most honest numbers, although you could also run ganglia agents inside your VMs as well. Again, how they communicate (i.e. is multicast available) will detemine how easy/hard it is to get functioning.