SOA is Dead (but the corpse is still kicking)

In a famous post from January this year (which I missed) Ann Thomas Manes declares SOA dead. She is a Reasearch Director within the Burton Group, has worked with SOA in the Burton Group and elsewhere, and is a co-author of the WS-* specifications.

The post has sparked fierce defense from vendors like Oracle. During the half day SOA Architect forum in Geneva this Tuesday, Oracle spent the first seminar repeating that “SOA is not dead” like a mantra, I guess in order to reinforce the message. It seemed to be one of the mayor points they wanted to get across.

Excerpt from Ann Thomas Manes post SOA is Dead; Long Live Services

Successful SOA (i.e., application re-architecture) requires disruption to the status quo. SOA is not simply a matter of deploying new technology and building service interfaces to existing applications; it requires redesign of the application portfolio. And it requires a massive shift in the way IT operates. The small select group of organizations that has seen spectacular gains from SOA did so by treating it as an agent of transformation. In each of these success stories, SOA was just one aspect of the transformation effort. And here’s the secret to success: SOA needs to be part of something bigger. If it isn’t, then you need to ask yourself why you’ve been doing it.

The latest shiny new technology will not make things better. Incremental integration projects will not lead to significantly reduced costs and increased agility. If you want spectacular gains, then you need to make a spectacular commitment to change. Like Bechtel. It’s interesting that the Bechtel story doesn’t even use the term “SOA”—it just talks about services.

And that’s where we need to concentrate from this point forward: Services.

This falls in line with my understanding that SOA without BPR/BPM/Transformation really does not amount to much. You need the entire organization to support a process and service view on business and IT in order to see real benefit.

In another post SOA is Dead? It’s About Time by Kurt Cagle acknowledges Ann Thomas Manes view but complements the picture with adding that

Perhaps my biggest reservation about SOA had to be the fact that, at the end of the day, it was still an RPC model that concentrated primarily on calling APIs that differed from one provider to the next. The result of this thinking is the sea of APIs, where there are now tens of thousands of APIs, each of which doing things a little (or in some cases, a lot) differently from one another, with very little cohesion, and with little thought to the semantic complexity that comes when you have that many microlanguages all competing for programmer attention.

Purists may argue that over time the SOA model (especially the SOAP/WSDL model) had been moving towards a more messaging-oriented architecture, but I’d counter that all that a messaging queue does is to decouple the receipt of the message from the response – if the message processor invokes a service, it is still an RPC, especially when transactions are involved.

This is one of the reasons that I think that resource oriented services – RESTful services – are beginning to gain real traction even as the big-box SOA projects are falling to the accountant’s axe. The publish/subscribe model in which what you’re publishing are not blogs but data documents (think XBRL or HL7) performs the same type of decoupling that message-oriented SOA did, but completely abstracts the intent from the process of communication.

This is consistent with my view that SOA, which if done correctly, should be document or data driven and should rely on messaging. As an alternative to an ESB used mainly for RPC over SOAP Web Services, I think that an REST-ful approach should be seriously considered when attempting SOA. Some thinkers at Gartner have started talking about a WOA – Web Oriented Architecture – as further constrained subset of the SOA approach based on REST principles.

I believe the change will be heavily resisted by companies like Oracle and IBM since there is less money to be made on the simpler and less tool/platform-intensive REST-ful approach to enterprise computing. Also they all have invested heavily in the WS-* and RPC-style SOA corner and thus are reluctant to change. But change will come sooner or later and the ongoing economical crisis will be a strong driver.