"The only constant is change" and the world of Service Oriented Architecture (SOA) is no different. No matter how much upfront business process modeling is done, or how perfect your service granularity is, or how wonderfully compliant you are with WS-*, the reality is that your services will have to change to keep pace with change - business agility implies change. And if your SOA has been working, there should be a whole host of consumers of those services who will not be happy at all with having to change. Change involves project cost, cost requires budgetary approval, and approval requires a Business appetite for the change. But since the change won't always appear to benefit the Business, it will very often not be approved, and your SOA will go the way of most system landscapes: to legacy, riddled with complexity, redundancy and consequent fragility.
Showing posts with label reuse. Show all posts
Showing posts with label reuse. Show all posts
Wednesday, 1 September 2010
Thursday, 22 October 2009
What do I put in my SOA service registry?
I'll talk later about asset management, but for now, what exactly belongs in the Service Oriented Architecture (SOA) service registry?
Well, services obviously, stupid.
But what about stored procedures? Or legacy, remotely invokeable services? Or batch feeds? Or ETL (Extract Transform and Load)?
Well, services obviously, stupid.
But what about stored procedures? Or legacy, remotely invokeable services? Or batch feeds? Or ETL (Extract Transform and Load)?
Wednesday, 21 October 2009
SOA Service Registry/Repository
How exciting. At long last I am a working somewhere with thousands of services, a SOA registry/repository, a service registrar and established governance processes around the use of services.
Could life get any better for an SOA believer?
Yes, because unfortunately some groups have decided that all this stuff is too much bother and have come to a peer-peer arrangement regarding the use of services.
So the registry is inaccurate.
So the whole house of cards collapses in a horrible, useless heap.
You see, reuse like recycling only works if the there are practical as well as ideological reasons for doing it. In this case either the governance was not strong enough, or the populace were not sufficiently bought into the enterprise benefit of SOA. Take your pick.
Lesson? A registry does not an SOA make, whereas an organisation (emphasis on organise) just might have a chance.
Could life get any better for an SOA believer?
Yes, because unfortunately some groups have decided that all this stuff is too much bother and have come to a peer-peer arrangement regarding the use of services.
So the registry is inaccurate.
So the whole house of cards collapses in a horrible, useless heap.
You see, reuse like recycling only works if the there are practical as well as ideological reasons for doing it. In this case either the governance was not strong enough, or the populace were not sufficiently bought into the enterprise benefit of SOA. Take your pick.
Lesson? A registry does not an SOA make, whereas an organisation (emphasis on organise) just might have a chance.
Wednesday, 22 October 2008
What is SOA - Service Characteristics - Composable
Composability is the ability of services to be used in orchestration scenarios by higher level services or processes. It is a special case of the reusability characteristic in that the services need to be uniform as well as reusable. The reason for this primary reason for this requirement is that the orchestrating service will in all probability but built using something like BPEL not a conventional programming language, so any variations in service style become more difficult to deal with.
Wednesday, 15 October 2008
What is SOA - Service Characteristics - Discoverable
For services to be of use of anyone they must be discoverable. Discoverability is usually taken to refer to the ability for consumers to find a relevant service by attributes (tags) at runtime via a service registry. In other words, consumers go to a service “yellow pages” and find at runtime services that best meet their needs.