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E54BAdvanced Architecture
Technologies & Solutions
Using an ESB to Build a SOA SOA/ESB/Legacy Integration
Bob Sadler
April 2008
© 2007 The MITRE Corporation. All rights reserved
Agenda
What is an ESB?Standards supportedWhat are the benefits?What do you do with it?Notional ESB architectureESB FeaturesHow does an ESB work?Pros and Cons of using an ESB to build a SOA
© 2007 The MITRE Corporation. All rights reserved
What is an ESB?
ESB – Acronym for Enterprise Service Bus Middleware/integration backbone that ties applications,
services, and resources together within a business area Connects Web services, J2EE, .NET, B2B, Portals, and
Legacy applications (i.e., databases, ERPs, CRM, programs, etc.)
Defines service mediation (i.e., intelligent message routing, transformation, and monitoring)
Allows publishing and discovering of services (WSDL/UDDI) Enables the connection of software running in parallel on
different platforms, written in different programming languages, and using different programming/data models
Provides service governance, security, and error handling
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Generic ESB Architecture
Enterprise Service Bus
B2B(Partner
Systems)
Legacy
Applications
Portal
J2EEApps
.NETApps
WebServices
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What are the benefits?
Simplifies the integration process and the reuse of business components
Adapts easily to new business requirementsEasy to use, lower-cost, and standards-based
integrationEnables incremental application development and
deployment, thus reducing risk and up-front investments
Centrally managed
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Standards Supported
WSDL, SOAP, UDDI, WS-Addressing, WS-ReliableMessage, WS-Security, WS-Policy
XML, XML Schema, XSLT, XPath, and XQueryJMS, JCA, J2EE
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What do we do with it?ANSWER: Integrate ApplicationsMost organizations have legacy systems, and new
applications that they want to buildMany of the legacy systems need to be integrated
along with the new applicationsMany of the legacies are in a client/server
configurations (tightly coupled)Some of the new applications could be SOA
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Notional ESB Architecture
Enterprise Service Bus
DB DBDB
Service Management
Service Registry
Portal
Web ServiceApps
Business Process
Mgmt (BPM)Test
Manager
Data Service Layer
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User Capabilities
Can input requests, services, and commands through client application or portal
Can view/output responses, services, and commands through client or portal
Can define business processes/services through Business Process Management (BPM)
Can orchestrate business processes with Business Process Execution Language (BPEL)
Can create/maintain/execute policies (i.e., governance) through service registry/repository
Can have service and transport-level security Can develop/implement/test through test management tools Can integrate databases through Data Service Platform
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Vendor Specific Products “My Experience”
ESB – BEA AquaLogic Service Bus (ALSB)Data Service Layer – Composite Data Service
PlatformDatabases – Oracle 10gTest Manager – iTKO LISAPortal – BEA AquaLogic Portal
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ALSB Features (1)
Intelligent routing– Message routing according to XQuery-based policies or call-
outs to external Web services– Support for both point-to-point and one-to-many routing
scenarios to support request-response and publish-subscribe models
– Dynamic routing destinations that enable service destinations to be set dynamically in the proxy pipeline. External rules can be configured to feed the actual business service to be routed at run time
Message brokering– Support for multiple messaging models including
synchronous, asynchronous, and publish-subscribe– Support for multiple message formats including SOAP, SOAP
with attachments, XML, structured non-XML data, raw data, text, and email with attachments
– WS-I compliance for SOAP/HTTP messages
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ALSB Features (2)
Message transformation– Validates incoming messages against schemas– Dynamic service selection, based on message content or
headers with the ability to transform messages based on the target service
Message transformation based on XQuery or XSLT– Multiple formats: XML and structured non-XML data
Service bus security– Supports authentication, encryption and decryption, and digital
signatures as defined in the Web service security (WS-Security) specification
– Uses SSL to support traditional transport-level security for HTTP and JMS transport protocols
– Supports one-way and two-way certificate based authentication– Supports message-level security– Supports HTTP basic authentication
© 2007 The MITRE Corporation. All rights reserved
ALSB Features (3)
Service Level Agreement (SLA)
– Administrators can set SLAs on a variety of attributes including throughput times, processing volumes, success/failure ratios of messages processed, number of errors, security violations, and schema validation issues
– Administrators can configure alerts for SLA rules violations and trigger automated actions, and send alerts to the console, or email
Error handling
– Allows you to configure your system to format and send error messages, and return messages for consumers of services who expect a synchronous response
Testing
– Provides a built-in test console in the development environment
– Allows you to test inline XQuery expressions used in the message flow
Logging and monitoring
– You can gather statistics about message invocations, errors, performance characteristics, messages passed, SLA violations, etc.
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How does ALSB Work?
Application client– Service consumer
ESB– Proxy service – Intermediary Web service that exchange
messages with client; Proxy services are published by ALSB; defined in terms of WSDLs, pipelines, routes, and branches; sends and formats messages to appropriate business services
– Business service – Enterprise services that ALSB will route messages to; any service not implemented in pipeline; represent services external to ALSB; client stub
Existing service– Back-end services
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Intelligent Message Brokering
ProxyService
BusinessService
ApplClient
BackendService
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SOA Development
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Cons of using an ESBto Build a SOA
Don’t use ESB-oriented architecture, if it does not have “business value”. SOA must be based on business requirements
An ESB is a means to an end, not the end itself SOA approach consists of several components
such as service producers, service consumers, service registries and repositories. These components must be defined and developed first, then integrated with an ESB
Integrating ESB with other software may be difficult, particularly legacies
Organization may have to develop new skills, techniques, and technologies
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Benefits of ESB Prototype
Do an ESB prototype firstStarting point for developing and evaluating tangible
and reusable SOA services and productsEnables a means of testing services with portals,
databases, and other applicationsProvides a means of training staff on SOA/ESB
concepts, development (i.e., SOA/ESB analysis, design, implementation, and testing) and tools
Provides “lessons learned” before you build a production SOA integrated environment
Production cost estimates and development schedules can become more accurate and realistic because of the experience gained from building an ESB prototype
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SOA Development
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SOA Guiding Principles
Gain buy-in to service-oriented design from senior executives and stakeholders, based on the benefits they will receive from a SOA approach.
Share “lessons learned” among SOA development and implementation teams to avoid duplicating earlier mistakes
Create a SOA roadmap/development plan based on enterprise business strategy
Define IT design and development policies, best practices, and standards
Educate staff about SOA policies, practices, products, and tools Survey SOA range of technologies and techniques Implement SOA governance process that ensures teams are
following design and development policies, architecture, and best practices
Regularly measure the results of the SOA adoption in terms of added business values to the organization
Leverage your legacy systems (e.g., existing architecture, infrastructure, and investments)
Define a step-by-step procedure detailing how the SOA will be tested
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Service Lifecycle Phases
Planning
Define/Develop services
Discover services
Integrate services
Orchestrate services
Secure services
Manage services
Test services
Deployment
Access services
Analyze SOA/services and environment
Monitor services
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Planning
Define the business value upfront (i.e. make a business case)
Define the scope of SOA (i.e., business processes, number of services, organizations, external users, etc.)
Establish boundaries and alignments with current and future business and IT initiatives
Use a phased approach, starting with a single, low-risk application or a pilot program that spans business functions and eventually expand to an enterprise SOA
Use architecture guidelines, requirements, and policies Define SOA standards Define roles and responsibilities Assess the maturity of the current and desired target state,
followed by a roadmap for transformation toward SOA Define SOA tasks Plan task schedule and resources Start the governance process
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Define/Develop Services Create service candidates by defining roles and collaboration
as stated in business processes Identify candidates for potential business services from
business model Potential business services should be reusable Design and build services that correspond to specific steps
within a business process Identify services that can be combined into a composite
service or application for carrying out a specific business function
Use a Business Process Management (BPM) tool
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Discover Services Define the service registry/directory Service directory acts as service broker between service provider
and service consumer. It registers the services through its metadata or service contracts (i.e., it hold data about the services).
Define service providers and consumers Service provider is a person, department, organization, or application
that offers the service. It registers service contracts to the appropriate service –brokering nodes. Define Service Level Agreements/Contracts and metadata.
Service consumer is a person, department, organization, or application that finds services with which its client would like to bind and interact. The service consumer may query service broker to find contracts and the metadata associated with services (i.e., service location, methods or remote services, message input/output formats, policies, and other parameters that a client uses to bind to a service)
Service broker is an entity that facilitates registration, location, discovery, retrieval, synchronization, replication, and/or delivery of service
© 2007 The MITRE Corporation. All rights reserved
Integrate Services
Integrate services with other services, applications or IT systems such as databases, data transformation services, reliable message delivery with routing, monitoring, and management (i.e., could be ESB and Service Management tools )
Integration often requires transformation of data to map between different data schemas, as well as dynamic routing for connecting the appropriate services at run time. This can be done in a Data Service Platform (DSP).
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Orchestrate Services
Orchestration is the combining of services into seamless, reliable process flows
It differs from integration, because orchestration is the sequencing of services to fulfill a business task or process
Orchestration is also called “gluing” services together into flow logic
Can be done in Business Process Execution Language (BPEL) and Business Process Management (BPM)
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Secure Services
Define service security policies Define user access in SOA environment (i.e., authorizing
and authenticating users, as well as provisioning them and managing their identities) must be mapped out before potentially sensitive information is exposed as a service
Identify services and data with security requirements Provide information security controls to security
requirements May be implemented in the Service Registry and/or ESB ESB provides message and transport level security Web service security standards can be applied (i.e., WS-
Security, SAML, SSL, XML-Signature, XML-Encryption, etc.)
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Manage Services
Define Service Level Agreements (SLA)s for services, and how to enforce them
Create SOA operational policies for daily operations, maintenance, auditing and billing (if appropriate) of services
Define metrics for service performanceMay be implemented and enforced in Service
Registry and Service Management
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Deployment
Deployment Considerations:– Cross domain requirements– Physical facilities/power– Does services require 24/7 availability– What are the security and scalability requirements– Maximum number of concurrent users– Service transaction time requirements– Tools, training, and technologies– Configuration and version control– C&A and COOP/DR requirements
© 2007 The MITRE Corporation. All rights reserved
Service Access
Services are typically exposed to users through a portal or a composite Web application
May also be exposed through wireless devices such as cell phones and handheld devices
SOA environments support multi-channel access to services and enable organizations to adapt user interfaces without modifying underlying services
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Analyze Services
Periodically analyze services, events, and business processes involved in the business operations
Define how operational managers and users can effectively monitor, analyze, and respond to time-sensitive issues
Identify bottlenecks and other problems in the process and alert the appropriate personnel when a particular event warrants attention
Analyze if all requirements are being met
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Monitor Services
Monitor the service execution and results Ensure that the services are reliable, available,
and constantly monitored for exceptions or failures
Services can be monitored through the ESB, and performance tested with a Service Test Manager
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SOA/ESB Lesson Learned 1
Do an ESB prototype first ESB as an integration and SOA solution is still a new
technology– Getting trained and skilled people may be a problem– Integrating ESB with other software may be difficult
Standards and best practices are still maturing Organization may have to develop new skills, techniques, and
technologies Management must endorse and enforce governance from the
beginning Security must be considered from the beginning (i.e., SOA
Security, Web Service security, Defense-in-Depth, DoD compliance, etc.), and you can never start the C&A process too early
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SOA/ESB Lesson Learned 2
Performance requirements (i.e., reliability, availability, scalability, transaction time, response time, etc.) should be defined and tested, performance may be an issue
SOA may not be the answer for all legacy integrations
Demonstrate the ESB capabilities to stakeholdersUse vendor experts as much as possible to assist
with developmentProvide training to users
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The End
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