Most industry experts I’ve talked to about SOA governance seem to agree that the top-down approach is something you see at enterprises with mature IT departments that may have already been doing SOA for a while. This made it rather interesting when MuleSoft released a new ESB manager, claiming that a tools-based governance approach works better because it lets developers meet business needs with services in a much more agile fashion.
For those just joining the debate, top-down governance looks at developing a portfolio of services by first having architects and business managers meet and work out a plan. Policies are then crafted for developers to follow in building out the needed services. A bottom-up approach removes much of the bureaucracy and lets development teams dive right into building and integrating services, often guided by management utilities called ‘governance tools.’
At Oracle, more than half of customers use a bottom-up approach, said Maneesh Joshi, senior group manager of product marketing for Oracle SOA products.
“The decision of governing bottom-up vis-à-vis top-down is really a function of where the customer is on the maturity cycle of SOA adoption,” said Joshi. “We mostly see our customer moving up the maturity cycle and not down to merit a change in the governance strategy from top-down to bottom-up.”
Yet MuleSoft says enterprises are becoming disillusioned with the ‘Big Bang,’ top-down approach to governance. The company says that for all the planning between business and IT, the ROI is rarely as strong as desired after a lengthy and expensive top-down implementation cycle.
Non-vendor architects I’ve talked to say the typical road is to start with some smaller departmental SOA projects and then move to a top down approach when the SOA benefits are proven – or when the services get redundant and out of control.