Xen is an open source virtualization platform that allows you to install a bare metal hypervisor on a machine, which turns it into a host for other guest VMs.
I can't really understand what OpenStack/CloudStack/Eucalyptus are, because their buzzword-riddled press releases make it difficult, as an engineer, to understand exactly what these technologies do/offer, but my best understanding is that they allow you to build out your own platform-as-a-service.
But I'm curious about what types of relationships, if any, Xen could have with OpenStack. Specifically, if I have a physical machine with the Xen server/hypervisor installed on it, how could I integrate it with OpenStack?
- Does OpenStack install as a guest VM/domain, and is thus controlled by the Xen hypervisor?; or
- Does OpenStack act as a plugin to the Xen hypervisor (and/or controller domain) itself?; or
- Does OpenStack get installed on its own physical server, and then sit on top of all the guest VMs/domains of 1+ Xen hypervisors?; or
- Something else?
Concrete examples are usually the best way to get me to see the "forest through the trees". Thanks!