> It would also suggest that the level above that is abstracting datacenter's away to just manage a single global system made up of multiple DC's. I work on Cl

> It would also suggest that the level above that is abstracting datacenter's away to just manage a single global system made up of multiple DC's. I work on Cloud Foundry. We already have this tool, at least for the IaaS layer. It's called BOSH[1], and it allows no-downtime deploys and updates of very large PaaSes (such as our own Pivotal Web Services). In our reference Cloud Foundry configuration, cf-release[2], we define a deployment manifest that can install a Cloud Foundry instance that spans two AWS availability zones. We dogfood this system every week. Sometimes twice per week. Our entire Pivotal Web Services system is updated, live, online. And basically, it's very rare that anyone notices. Which is awesome. [1] https://github.com/cloudfoundry/bosh https://github.com/cloudfoundry/bosh [2] https://github.com/cloudfoundry/cf-release https://github.com/cloudfoundry/cf-release