I looked around via Google and Superuser's search function and I was unable to find anything directly answering this question, so I hope I'm not reposting this...
An organization I work with recently had the good fortune to receive a massive amount of machines and now we are discussing what we will do with them. As the organization is focused on security training, I was thinking putting together a private cloud would be our best option. The hardware we have now is a mix of Dell Poweredge 1850s, 1750s, and 1650s, so the processors we are working with are mostly 32-bit and I do not think many of them (if any at all) have virtualization extensions.
That being said, I am looking for the best opensource cloud platform (in terms of scalability and modularity). We may be adding and removing physical machines at random and if the cloud software readily supports this sort of "hot-swapping" that would be great. If anyone has worked with EC2 or Rackspace's cloud solution, the interfaces that they have are what I am looking to put on this cloud (putting up and taking down VMs at will, storing images on a local fileserver). In terms of network connectivity, we will likely be NAT'ed behind a public IP, so the setup will need to support that as well.
I know this is a very specific request, but if anyone could point me in the right direction I would greatly appreciate it.
Thank you in advance for your help!