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Service Oriented Architecture Service Oriented Architecture
What it is and why you need it.
April 25, 2007 SOA: What it is and why you need it. Slide 2/19Final
AgendaAgenda
Why SOA What is SOA? Government of Canada SOA Oracle SOA Suite Some of the Challenges Conclusion
April 25, 2007 SOA: What it is and why you need it. Slide 3/19Final
Why SOA?Why SOA?
“The business simply wants composable, reusable, interoperable, unbreakable components they can leverage in flexible ways to meet the changing needs of the business.”
ZapThink Dec 11, 2006
April 25, 2007 SOA: What it is and why you need it. Slide 4/19Final
Why SOA?Why SOA?
“Departments have a huge investment in their application environment, horizontal government programs and mandates are becoming increasingly common, new development is so expensive – there must be a better, faster, cheaper way to do things.”
IT/NET, April 2007
April 25, 2007 SOA: What it is and why you need it. Slide 5/19Final
What is SOA? What is SOA? Some definitionsSome definitions
Service “useful labour that does not produce a specific
commodity” “a facility supplying some public demand”
Source: Merriam-Webster Online
Architecture The description, through words and/or pictures of the
elements of a system and their interactions with each other and with other systems
Service Oriented Architecture The description of the system elements that enable the
supply of something useful which has a public demand
April 25, 2007 SOA: What it is and why you need it. Slide 6/19Final
What is SOA?What is SOA?ExampleExample
April 25, 2007 SOA: What it is and why you need it. Slide 7/19Final
What is SOA? What is SOA? Elements of SOAElements of SOA
Defined Service Types Tells developers how to approach a task Guides analysts in “what’s possible” Shows how to do the same thing on multiple platforms
Process Driven Software A transition away from the traditional task- centric
Applications Designed to mirror the way people work Consumes services in support of processes Permits transfer of data/functionality across organizational
boundaries Exposure of existing software components as services Build as you go
April 25, 2007 SOA: What it is and why you need it. Slide 8/19Final
What is SOA? What is SOA? Defined Service TypesDefined Service Types
Service
Contract
Implementation
Business Logic Data
Interface 1Operation aOperation b
.
.
.
Interface 2Operation aOperation b
.
.
.
Services Types support: Estimating Consistency of
implementation Communication Reusable Functionality
April 25, 2007 SOA: What it is and why you need it. Slide 9/19Final
SOA Metamodel
What is SOA?What is SOA?Process Driven SoftwareProcess Driven Software
Service Model
Business ModelPlatform-Dependant Models
Platform-Dependant Models
Platform-Dependant Models
Platform-Dependant Models
Business Process Definition
Requirements Implementation
Service Oriented Process
April 25, 2007 SOA: What it is and why you need it. Slide 10/19Final
What is SOA? What is SOA? SummarySummary
Service Oriented Processes and system working together to provide
something of value Architecture
The definition and communication of: how it is done and how to do it
The ultimate value provided by Service Orientation is that it permits existing software assets to be used longer, in more ways that mirror the way your organization does things
April 25, 2007 SOA: What it is and why you need it. Slide 11/19Final
The GC SOAThe GC SOA Treasury Board-CIOB is actively engaged in developing and
distributing an SOA for the Government of Canada It provides guidance and a foundational reference framework
for a common approach to application interoperability Identifies 3 layers (tiers)
Technology Component Layer “Understanding, classifying and purposing all GC IT
Architectures” Service Exchange Architecture
“Standardizing the run-time aspects of the GC IT Enterprise” Describes Services of Services (“Automated Business
Services”) and “Infrastructure Services” Business Application Architecture
“Standardizing the design-time aspects of the GC IT Enterprise” Layered application architecture that allows Business Owners to
leverage pre-built services
April 25, 2007 SOA: What it is and why you need it. Slide 12/19Final
The GC SOAThe GC SOA
Source:Government of Canada Service Oriented Architecture Series – Primer (http://www.tbs-sct.gc.ca/cio-dpi/webapps/architecture/p-gi/p-gitb_e.asp
Business Application Architecture
Enterprise Services Interface (ESI)
Interaction Layer
Persistence Layer
Object Layer
Process Layer
Application Services Bus (ASB)
Presentation Layer
April 25, 2007 SOA: What it is and why you need it. Slide 13/19Final
SOA ToolsSOA Tools
April 25, 2007 SOA: What it is and why you need it. Slide 14/19Final
Some ChallengesSome Challenges Resistance to change
Current monopolies on app development are reduced Perception that building something once means current
teams could start to run out of things to do – teams must find more specialized things
There are limits to what you can do The building block can only take you so far – at some point
you may need a Mechano set to build more complex things Components are interoperable with each other but not with
other kinds of components Creeping Complexity
An individual SOA component may be simple Overtime, the enterprise level SOA will become something
substantial - requires thought, planning and skill, i.e. architecture and training
April 25, 2007 SOA: What it is and why you need it. Slide 15/19Final
Some ChallengesSome Challenges Finding the right ‘granularity’
Differences in individual mandates and operations means differences in granularity are needed
Some Services will do very simple things (e.g. Return a single value)
Some will do very complex things (e.g. Update Local database, initiate an approval process, send to partner, then notify originator)
Complex services appear more valuable to the business but flexibility is reduced as complexity increases
There’s no “best” SOA Just like with Lego, you need a certain degree of variety and
personal choice Organizations will build a mix of Services at different levels of
granularity GoC SOA defines 2 levels: Business Services and Infrastructure
Services
April 25, 2007 SOA: What it is and why you need it. Slide 16/19Final
Conclusion:Conclusion:Architecture PrinciplesArchitecture Principles
Renovate, don’t rebuild You are not re-engineering, you are extending your existing
application environment through planning, design and management Always keep the critical objectives in mind
Alignment of systems and business Reuse of existing software Quick turn-around
You MUST decouple the System Architecture from the Software Architecture
Don’t try to map a traditional Client server tiers to SOA tiers SOA MUST extend to the ERP
The ERP is probably the single most significant software investment made by the department
SOA values comes from re-use and renovation, what’s the point if you aren’t re-using and renovating your biggest piece of technology.
April 25, 2007 SOA: What it is and why you need it. Slide 17/19Final
Conclusion:Conclusion:Going ForwardGoing Forward
Focus on your needs, engage key participants Determine Governance, basic standards Make sure you have a very good understanding
of your current assets Set priorities – look for services that are based on
new ways to use current technology Start defining Services and your SOA metamodel
Start with types based on GoC SOA as starting point
Extend them for what you need to do
April 25, 2007 SOA: What it is and why you need it. Slide 18/19Final
Conclusion:Conclusion:Service Oriented ArchitectureService Oriented Architecture
What it is An SOA is the description of the system elements that
enable the supply of something useful which has a public demand
An approach to quickly leverage existing software resources for new and more complex purposes
Why you need it Applications need to work more closely with other
agencies Need to integrate program systems more tightly with
Corporate Systems Need to improve the way applications are built
Increase flexibility, reduce cost, reduce time to deliver
April 25, 2007 SOA: What it is and why you need it. Slide 19/19Final
More informationMore information IT/NET - [email protected] Treasury Board - CIOB ZapThink.com Enterprise SOA – Service Oriented
Architecture Best Practices; Dirk Krafzig, Karl Banke and Dirk Slama;
Prentice Hall December, 2005 Software Engineering Institute:
http://www.sei.cmu.edu/architecture/definitions.html