Planning_and_Impleme.. - didier beck weblog
Planning_and_Impleme.. - didier beck weblog
Planning_and_Impleme.. - didier beck weblog
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www.butlergroup.com<br />
<strong>Planning</strong> <strong>and</strong> <strong>Impleme</strong>nting SOA<br />
The Role of Business Rules<br />
Business rules is one of those phrases that is reasonably understood, even if not always well-defined.<br />
Separating out such business rules from the tangled web of code where they are usually buried, is a valid<br />
exercise that will repay efforts whatever architectural style is the current trend. Rules should be visible,<br />
manageable, <strong>and</strong> therefore under the control of business people rather than technologists.<br />
Creating Generic Interfaces<br />
The major problem with many older technologies is that the interfaces to applications were often hardcoded<br />
with those applications, making it necessary to amend significant amounts of code any time a change<br />
was needed. Separation of interface from application is already a feature of n-tier architectures that is still<br />
valid in a SOA approach, <strong>and</strong> will still be relevant in the future. Future-proofing SOA can be achieved by<br />
continuing to create generic interfaces to older applications.<br />
SOA MANAGEMENT AND GOVERNANCE<br />
CATALYST<br />
Once services start to be deployed, the joint issues of SOA management <strong>and</strong> governance will dem<strong>and</strong><br />
attention. It is wise to plan for this early on in a SOA project, otherwise there is a risk that SOA will not<br />
deliver its expected benefits.<br />
SUMMARY<br />
Left unmanaged, services can rapidly degenerate into a tangled mess.<br />
Run-time management <strong>and</strong> governance of SOA will converge with traditional<br />
systems management.<br />
A clear definition of SOA roles <strong>and</strong> responsibilities supports good governance.<br />
St<strong>and</strong>ards for SOA governance are beginning to emerge.<br />
ANALYSIS<br />
Governance can be regarded as the discipline of managing desired outcomes through structured<br />
relationships, policies, <strong>and</strong> procedures. Good SOA governance should make it easier for organisations to do<br />
the ‘right’ things <strong>and</strong> harder for them to do the wrong ones. Governance can be achieved by creating <strong>and</strong><br />
then enforcing machine enforceable policies across the service lifecycle, from design time through to run<br />
time, <strong>and</strong> especially when services need to be changed.<br />
Left unmanaged, services can rapidly degenerate into a tangled mess.<br />
The key difference that Butler Group has identified between successful SOA projects <strong>and</strong> ones that fail to<br />
deliver benefits is in the area of good management <strong>and</strong> governance. Without a good human management<br />
infrastructure, even the best technology solution is likely to allow services created on it to degenerate into<br />
a confused set of services that do not get well used.<br />
Thomas Erl, in his book “Service-Oriented Architecture: Concepts, Technology, <strong>and</strong> Design”, lists a number<br />
of common pitfalls in adopting SOA:<br />
<br />
Building SOA in the way that distributed architectures have been built – this can introduce problems<br />
such as a proliferation of Remote Procedure Call (RPC)-style service descriptions, the creation of services<br />
that cannot then be composed with others, <strong>and</strong> the creation of non-st<strong>and</strong>ardised services.<br />
December 2006 Section 1: SOA Deployment 13