Pragmatic Dictator

In the last couple of years we’ve seen the arrival of the mashup which is at least on some level nothing more than the latest in a long line of terms for integration. Thus far most mashups consist of a simple amalgamation of a couple of services which leads to a very flat graph of service dependencies. Service dependencies are things like:

1. Data Schemas - structure of data provided by services
2. Endpoints - location of service be it a URL or a WSDL endpoint
3. Availability - whether a service is available for use
4. Reliability - whether a service that is available behaves as expected

These mashups are already at the mercy of the underlying services they are built on. The mashup provider has little control over these services. For the most part these mashups work but it’s because they have only a few moving parts such that the likelihood of issues is low.

Many enterprises have considerably deeper dependency graphs inside their firewalls and have to work hard to keep them stable. There’s probably some limit to what can be achieved once the dependency graph gets beyond a certain depth and it might well be that the maximum depth is smaller once external services are brought into the mix. The maximum depth is likely further reduced because these enterprises wish to treat external services as if they are part of their organization. They want to be able to integrate them using transactions, they want them to have the same level of reliability as what lives within their own data-centres, they want integrated security options etc.

I suspect that a lot of what can be done in a single enterprise (at substantial cost) such as high reliability is going to be considerably more (prohibitively?) complex to achieve across organizations. This is because the level of control required to achieve these targets is beyond that available across enterprises.

Right now I think there’s much effort being made to paper over these issues such as features in WS-*, SLA’s etc. I wonder if it might it be better to give up on this idea of control and build some simpler solutions….

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This entry was posted on Monday, March 5th, 2007 at 6:16 pm and is filed under Architecture, Distributed Systems. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.