I admit it, it's taken me a while to come around to the term inter-cloud, a concept being primarily promoted by Cisco as part of their Unified Computing platform. Lately the term seems to have been picking up some steam so I thought I'd take a moment to examine it a bit further.
My interpretation of the so called "inter-cloud" is the abstract ability to exchange information between distinct computing clouds (storage, compute, messaging etc) be it public or private in a uniform/unified way. I've come to think of it like a higher level inter-connected network atop the current world wide web via linked API's and data sources. Greg Papadopoulos from Sun calls it a Cloud of Clouds.
In one of the more thought provoking posts I've read in a long time, Vint Cerf (the father of the Internet & Google's Chief Internet Evangelist) compares the emergence of cloud computing and more specifically the inter-cloud to "the networks of the 1960s -- each network was typically proprietary. These networks were specific to each manufacturer and did not interconnect nor even have a way to express the idea of connecting to another network." Exactly the same problem we now face with the current generation of cloud infrastructure and services.
Cerf goes on to state the problem with the current inter-cloud is that "each cloud is a system unto itself. There is no way to express the idea of exchanging information between distinct computing clouds because there is no way to express the idea of “another cloud.” Nor is there any way to describe the information that is to be exchanged. Moreover, if the information contained in one computing cloud is protected from access by any but authorized users, there is no way to express how that protection is provided and how information about it should be propagated to another cloud when the data is transferred."
Interestingly he points to work being done by another father of the Internet, Sir Tim Berners-Lee (the inventor the World Wide Web) who has been pursuing ideas that may solve these so-called “inter-cloud” problems. According to Cerf, Tim Berners-Lee's idea is that by semantically linking data, we are able to create "the missing part of the vocabulary needed to interconnect computing clouds. The semantics of data and of the actions one can take on the data, and the vocabulary in which these actions are expressed appear to constitute the beginning of an inter-cloud computing language."
I understand this next statement may cause some lively debate, but I will say it anyway. If I am interpreting his assertion correctly, what the world needs is not yet another API to control the finer nuances of a physical or virtual infrastructure but instead a way for that infrastructure to communicate with other clouds around it regardless of what it is. The biggest hurdle to cloud interoperability appears to have very little to do with a willingness for cloud vendors to create open cloud API's but instead the willingness to provide the ability for these clouds to effectively inter-operate with one another. More simply the capability to work along side other cloud platforms in an open way.
Ever the visionary, Cerf says it best. The Cloud represents a "new layer in the Internet architecture and, like the many layers that have been invented before, it is an open opportunity to add functionality to an increasingly global network.." Amen brotha.