When I lamented, in a previous post, that I couldn’t tell you about recent submissions to the DMTF Cloud incubator, one of those I had in mind was a submission from HP. I can now write this, because the author of the specification, Nigel Cook, has recently blogged about it. Unfortunately he is isn’t publishing the specification itself, just an announcement that it was submitted. Hopefully he is currently going through the long approval process to make the submitted document public (been there, done that, I know it takes time).
In the blog, Nigel makes a good argument for the need to go beyond a hypervisor-centric view of Cloud computing. Even at the IaaS layer there are cases of automated-but-not-virtualized deployment that have all the characteristics of Cloud computing and need to be supported by Cloud management APIs. Not to mention OS-level isolation like Solaris Containers.
Nigel also offers a spirited defense of SOAP-based protocols. I don’t necessarily agree with all his points (“one could easily map the web service definition I described to REST if that was important” suggests a “it’s just SOAP without the wrapper” view of REST), but I am glad he is launching this debate. We need to discuss this rather than assume that REST is the obvious answer. Remember, a few years ago SOAP was just as obvious an answer to any protocol question. It may well be that indeed REST comes out ahead of this discussion, but the process will force us to be explicit about what benefits of REST we are trying to achieve and will allow us to be practical in the way we approach it.