S O A

SOA : It Takes 2 to Tango

Why talk about this ?
2 years on a project that relies heavily on web services (client + server)
And conclusion:
Rewards are obvious
Not so obvious: complexity ↑
Talking about a relationship

SOA
Service-Oriented Architecture:
is an architectural style that guides all aspects of creating and using business processes, packaged as services , throughout their lifecycle, as well as defining and provisioning the IT infrastructure that allows different applications to exchange data and participate in business processes regardless of the operating systems or programming languages underlying those applications. (Wikipedia)
Short: applications using Web Services

Aspects of complexity
Configuration
Availability
Performance
SLA
Change management

Configuration
Sometimes extra framework
Standards (OASIS: SOAP, WS-*, ... REST)
Opening to the world !
Transfer over the 'net !
Authentication
Confidentiality - encryption (HTTPS enough ?)
Integrity
Security

Availability
Your application may depend on external servers
Downtime of these servers ?
Malfunction of these servers ?
How fast is a problem fixed ?

Performance
Old times: only your infrastructure matters
SOA: will the queried servers withstand the load ?
How will their response times be for extreme loads
End-to-end load testing ! (goodwill !)

SLA: Service Level Agreement
Contract covering availability, and sometimes performance
But: only effective if there are sanctions ...
... will the server side accept to sign this ?
Only if you have serious leverage:
Financially
Reputation-wise
(internal)
Far from always the case !

Change management
Sometimes, change is necessary
For your organization: leverage ? How flexible is their release procedure ?
For their organization: documentation + communication ?
Documentation: technical + functional

Before considering WS
As a Client
How stable ?
How important are you to them (SLA) ?
How critical is it to you ?
What will it cost ?
As a server
Which load is expected ?
Will they sue ?
What can you charge, and will it cover your maintenance ?

To sum it up ...
Desirable: good partnership with other organization
If not: legally binding agreements – only possible if leverage.
A few years ago: hype ... now: reality check
Look up: SOA Governance

Lots of rewards ... ... Lots of work .

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S O A

by guestf87b10 on Dec 01, 2007

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S O A — Presentation Transcript