As has been noted by many commentators, there's an irony at the heart of cloud computing. Although most cloud computing offerings use open source for their infrastructure – you'd be crazy not to if you want it to scale affordably – the very premise of clouds is that the operating system becomes irrelevant.
So the large-scale use of open source to run clouds might, it is said, cause open source on the desktop to become irrelevant (along with Windows, of course).
Today each infrastructure-as-a-service cloud presents a unique API that developers and ISVs need to write to in order to consume the cloud service. The deltacloud effort is creating a common, REST-based API, such that developers can write once and manage anywhere.
A cloud broker if you will, with drivers that map the API to both public clouds like EC2, and private virtualized clouds based on VMWare and Red Hat Enterprise Linux with integrated KVM.
The API can be test driven with the self-service web console, which is also a part of the deltacloud effort.
While it is a young project, the potential impact on users, developers, and IT to consume cloud services via a common set of tools is epic.
I'm not quite sure about the “epic” bit, but it's certainly clever. If the operating system is being abstracted away by clouds, Red Hat seems to be saying, the best thing to do is to abstract away the entire cloud computing layer by hiding all the different APIs currently out there with another API on top – by means of open source code running on GNU/Linux – and writing to that.
As Red Hat puts it:
The goal is simple. To enable an ecosystem of developers, tools, scripts, and applications which can interoperate across the public and private clouds...
...and to make the latter vanish into thin air.