David Linthicum wrote an interesting piece the other day about “What SOA Can Learn from Cloud Computing and Vice Versa.” He includes some valid points about what companies need to address when building out services for the cloud and how they can learn from SOA.
I agree with the need for what David calls “service expandability,” or what I call service scalability. David says, “Cloud computing services are designed to expand as needed, and those leveraging cloud services do so because they can get the services on demand, when they need them. The ability to expand services within a SOA is typically a painful and expensive process.”
Scalability is a key factor in the consumer experience with the cloud. Consumers have a short attention span, and if scalability does not exist in the cloud services they use, then consumers will quickly lose interest and move on. An example is the scalability and subsequent service problems Twitter has had. Twitter’s “Fail Whale” has proven that consumers need scalability for their cloud services.
Another central issue for cloud providers that David highlights is Service Design. He says, “The reality is that services that are not well defined and designed won’t sell well when delivered on-demand, and thus those who provide services out of the cloud – which are most major cloud computing providers – have to spend a lot of time on the design of the services, including usability and durability.” Why is this?
With SOA, you have a private service with limited users, so for the most part you can make multiple revisions to services and APIs. But, opening services and APIs to the cloud brings new problems to service design. Once you open an API to the cloud you cannot change design as easily because there will be existing developers who have already built out your existing API. If you change the design, these developers’ APIs won’t work. So, David is correct in saying that well-designed service is extremely important from the get-go because you cannot change designs the way you can in the contained SOA environment.
There’s a lot that cloud computing can learn from SOA, and scalability and good service are just two examples. History always teaches ways to improve our current projects so it will be interesting to see the shape the cloud takes from what we’ve learned with SOA.
