migrating soa

So You Want an SOA: Best Practices for Migrating to SOA in the EnterpriseEric Newcomer, CTO

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OverviewFirst of all: concepts and definitionsChange your thinking about your IT environmentIncluding organization and skill setEmbrace heterogeneity and complexitySupport businesses agility to:Reduce complexityImprove integration and data sharingBecome more competitiveMove toward services and SOA adoption:Map IT services to business servicesStart with incremental changeUnderstand and apply architectural best practices

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Concepts and definitionsServices and SOA are technology independentThey represent “styles of design”Have been mapped successfully to CORBA, WebSphere MQ, Web servicesN-tier technologies are the best fitCORBA, Web servicesA service includes:A requesterA providerOne or more message exchange patterns

Requester Provider

UDDIRegistry

SOAP

WSDL

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Concepts and definitions (cont)Services model human and business functionsNot software artifacts such as databases or filesUnlike objects, services are not “things”Services are defined by the messages they exchangeRequest list of customersUpdate the customer’s orderNotify the call center operatorTransfer my funds The design concept is the message schema

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Credit Suisse: SOA pioneer

Enterprise Services

INFORMATION BUS

MS - COM COMet

MS - COM COMet

Service ContractService Contract

C++ CORBA(ORBIX 3)

C++ CORBA(ORBIX 3)

Service ContractService Contract Service ContractService Contract

Java CORBA(ORBIX 3)

Java CORBA(ORBIX 3)


Smalltalk-/SecureBrokerSmalltalk-/

SecureBroker


WebLogic-Orbix Java 3.3.1


IIOP-----SSL

IIOP-----SSL

Mainframe PL1 Resources



TivoliManagement

TivoliManagement


HP OpenViewManagement



MainframeCICS Resources



Mainframe IMS ResourcesMainframe

IMS Resources

Enterprise Services

Enterprise ServicesEnterprise Services

INFORMATION BUS

MS - COM COMet

MS - COM COMet


C++ CORBA(ORBIX 3)

C++ CORBA(ORBIX 3)


Java CORBA(ORBIX 3)

Java CORBA(ORBIX 3)



SecureBroker




MS - COM COMet

MS - COM COMet


C++ CORBA(ORBIX 3)

C++ CORBA(ORBIX 3)


Java CORBA(ORBIX 3)

Java CORBA(ORBIX 3)



SecureBroker




IIOP-----SSL

IIOP-----SSL




TivoliManagement

TivoliManagement








Mainframe IMS ResourcesMainframe

IMS Resources

Enterprise Services

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Services change the organizationA service architect determinesThe overall plan and design for servicesWhich services fit the model, which don’tDesign principles for services, especially reuseDevelopers update their skillsLearn to develop for future reuseWork with multiple technologies (Web services plus an execution environment – J2EE, CORBA, .NET)Business analysts may compose servicesGiven right levels of abstraction and toolset

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Services embrace heterogeneityHeterogeneity and complexity are constantServices can abstract across any software systemApply “veneer” using XML and Web servicesExtend for enterprise qualities of serviceUnique characteristics are valuableMake complexity work for youJ2EE, .NET, CORBA, and Mainframe all have benefitExisting applications have functions with valueModernize without the expense of replacementMaintain enterprise QoS – reliability, transactions, security

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Typical IT complexity map

Source: Deutsche Post World Net, SAP SI

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• A “plug and play” view of IT architecture and systems

• Native interoperability and integration capabilities now available for every system end-point via a standards-base service interface

• Orchestration of core business processes, independent of underlying systems and adaptable to changing business conditions

• Investments in standards to help drive down long term operating costs and as a mechanism for insuring future interoperability between infrastructure and systems

• A “plug and play” view of IT architecture and systems

• Native interoperability and integration capabilities now available for every system end-point via a standards-base service interface

• Orchestration of core business processes, independent of underlying systems and adaptable to changing business conditions

• Investments in standards to help drive down long term operating costs and as a mechanism for insuring future interoperability between infrastructure and systems

Desired goal

SOP (Service Oriented Platform)

Business ProcessArchitecture

IT ApplicationLandscape

SOP (Service Oriented Platform)SOP (Service Oriented Platform)

Business ProcessArchitecture

IT ApplicationLandscape

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Bank Teller analogy

Different types of tellers offer different servicesTellers specialized to perform certain types of transactions:

Account Management (Opening and closing accounts)Credits (inquiries, consulting, applying for mortgages)Cash Register (Withdrawals, deposits, funds transfers)Currency exchange (buy and sell foreign currencies)

Several tellers may offer the same set of services (for load balancing / failover)What happens behind the counter is not your business (but the IT systems need to support the tellers)If you require a complex transaction, you may have to visit several tellers (customer as transaction coordinator)

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Move from monolithic applications in stepsIntermediate stage:

Break out individual services

Application

Application

service

service

Application

Application

service

Goal: Service-oriented architecture

service

service

service

service

Application

Monolithic applications

Application

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Reasons to develop servicesNot for the sake of the individual applicationsServices don’t make sense in a mono-technology environmentFocus on reusability, component design, data sharingFor the sake of the next level developersOffice workers, business analystsCan share data without worrying about details of underlying implementationLay the foundation for future applicationsInfrastructure investment in “agility”

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Service Contracts Are the Key

The key principles of service-oriented architecture (SOA)Services should be business-orientedServices should have well-defined interfaces (aka service contracts)Service contracts should separate interface from implementation Service contracts are critical to achieve reuse and abstraction

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WSDL is best for service contractsWSDL is very flexible:

Import existing WSDL contractsCreate new WSDL contracts using

XML SchemaCreate new WSDL contracts from an

external metadata source such as CORBA IDL

Annotate with policy metadata

BenefitsAbstractionEncapsulationLoose-CouplingSeparation of Concerns

Service

Port

Binding

XML Data Type

Part

Message

Operation

PortType

WSDL

LogicalContract

PhysicalContract

•Logical Contract is what other applications care about• Physical Contract is extensible to support any middleware binding• XML Schema provides independent type system

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An important question: How to decompose services?

Quality criteria used to measure the result:

1. Derived from top rank use cases (adequateness)2. Balanced with existing assets: platform technology,frameworks, components3. Balanced with requirements (trade-offs, performance vs. security,…)4. Compliance with (domain-specific) industry standards andreference models (interoperability, readiness for merging)5. Designed to make the system more resilient to futurechanges (20 years?) (maintainability)6. Designed for substantial reuse, and with substantial reuse7. Intuitively understandable (people buy-in!) (usability)

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Considerations for SOA design

FunctionalitySoftwareArchitecture

Fault Tolerance

PerformanceCostThroughput

Capacity

Availability

Interoperability Fail safe

Maintainability

Scalability

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Take the example of the Web

Human to computer interactions resolvedStandards in place for programming (HTML) and interoperability (HTTP)Huge value adds Highly productive, low cost Standardization at the network endpoints

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Web Services: Composites for IT

Standards (WSDL & SOAP) and approach (SOA) need to be deployed – at the endpointsOpen source will help drive adoptionJoin Web 2.0 mashupsto enterprise dataCICS IMS

C, C++, COBOL, PL/I, Java, C#

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PackagedApplications

Message Queuing/EAI

.NET, Java, Application

Servers

Databases and Files

WSDL

Leverage the power of the endpoints

WSDL WSDL WSDLSOAP SOAP SOAP

WebServices

layer

Add servicesto the endpoints

to standardize them

Applications have a common interface/protocol for composites

Platform/Legacylayer

Legacy Legacy Legacy

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SecurityService

RetailerService

Credit CardService

Billing & Accounting

Service

OrderService

Result – Order Entry/Service Delivery

Telephone/Mobile Access

PC Access

DeliveryService

Satellite TV

Voice over IP

TV over IP

Services can be anywhere on the network, running on any platform, hosted by anyone

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SummaryEnterprises want business agilityThey become agile by investing in servicesKey benefits include:Rapid application integrationMulti-channel accessObtaining service functionality over the InternetCreating new business models

SOA requires a change in thinking and organizationThe agile business embraces heterogeneity Resolving differences via services and SOABest practices involve considering many capabilities