Daniel ShollerOK, so I have finally dug out from the backlog after attending our AADI conference in Las Vegas last week. It was nice to see some of you in person. One thing that always bothers me is that I never have enough time to answer all the questions that people ask during our presentations. In this case, we also had a fire alarm go off during the Q&A portion of one of my presentations (it was a false alarm). So I figured that I would try to answer them here.
The link to my presentations is here.
One of the major points of discussion was that as you plan how to adopt and make use of the ideas inherent in SOA, you have to remain cognizant of the benefits that you are trying to achieve. One of the main benefits is "agility" which roughly translates into the ability to change our IT systems at a rate that is sufficient to match the needs and expectations of the business environment. One question that we received was about how to quantify agility. There is some Gartner research on this topic (Gartner subscription required) that goes into great detail on how to do it. One other heuristic that I have seen used in a few cases has been just to measure the cost of change, and the time to make changes. People who are doing this usually divide the changes up into small, medium and large buckets based on some arbitrary criteria, and then figure out how much money and how many person-days have been applied to making those changes. While this will probably not mean much for small numbers, in a large organization this can give very good directional indications of whether SOA (or any other initiative) is having an impact on your agility.
The other question that was asked was whether WSDL was required for SOA. This is easy, in that the answer is a resounding NO. However, WSDL is most often used to implement the particular style of SOA that we refer to as RPC style SOA. In this style, services are essentially methods, and the messaging network is assumed (from the point of view of the endpoints) to be a WS-* and SOAP based network. In this situation, there is a lot of tooling that people use to simplify the programming of the interactions, and in most cases that tooling relies on WSDL files. (even in this case, they are not required, but given the tooling and how easy it makes things, it is pretty unlikely that anyone would choose to do without. ) In other styles of SOA, such as the WOA style,(Gartner subscription required) WSDL is not only not required, but usually does not play a role. (Note that WSDL 2.0 was designed to be used even with WOA style services, and there are other efforts, such as WADL, to create a description language for this style of SOA. However, most practitioners at this point do not believe such a construct is necessary. )
Most of the other questions were from the presentation on the current state of SOA, which highlighted some of our findings from our SOA surveys. (Gartner subscription required). The first one was about whether SOA adoption was consistent across industries. The answer is that it is not, but that in some cases the number of responses in a particular industry was small, so it was hard to be sure the proportions were correct. In general, we see the most SOA adoption in high tech sector with 100% of the survey responses saying they were pursuing SOA, to a low of 37% in retail. However please be aware that the margin of error in this is too big to use these percentages directly.
The final question was about why, while most of the people using SOA saw positive outcomes for their agility and for other factors, there were some people who had negative or even strong negative outcomes. Most of the reason for this is just human nature.. if enough people do it, the outcomes will be all over the map. Anecdotally, a lot of the cases where people have had failures in their SOA initiatives have been the result of inattention to governance. As part of the conference, my colleague Paolo Malinverno did a presentation on the major mistakes to avoid, that is a compendium of the learnings we have had from talking to these organizations.
Hope you all enjoyed the conference. If you did not get a chance to attend, you can do so at the next one this summer in Orlando.
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