Building on Multiple Cloud Providers

Are you building it on top of an existing cloud, or are you running your own servers? And how did you come to that decision? So currently we are building on multiple clouds. We don't have full production level systems running yet. That is lecking a part of the plan, but it isn't there yet. These abstractions allow us to actuall run on a particular cloud provider and then create a similar clust on a different cloud provider.