Implementing SOA: Total Architecture in Practice

Putting Service-Oriented Architecture (SOA) into Practice “This book is a must-have for enterprise architects implementing SOA. Through practical examples, it explains the relationship between business requirements, business process design, and service architecture. By tying the SOA implementation directly to business value, it reveals the key to ongoing success and funding.”         —Maja Tibbling, Lead Enterprise Architect, Con-way, Inc. “While there are other books on architecture and the implementation of ESB, SOA, and related technologies, this new book uniquely captures the knowledge and experience of the real world. It shows how you can transform requirements and vision into solid, repeatable, and value-added architectures. I heartily recommend it.”         —Mark Wencek, SVP, Consulting Services & Alliances, Ultimo Software Solutions, Inc. In his first book, Succeeding with SOA, Paul Brown explained that if enterprise goals are to be met, business processes and information systems must be designed together as parts of a total architecture. In this second book, Implementing SOA, he guides you through the entire process of designing and developing a successful total architecture at both project and enterprise levels. Drawing on his own extensive experience, he provides best practices for creating services and leveraging them to create robust and flexible SOA solutions. Coverage includes Evolving the enterprise architecture towards an SOA while continuing to deliver business value on a project-by-project basis Understanding the fundamentals of SOA and distributed systems, the dominant architectural issues, and the design patterns for addressing them Understanding the distinct roles of project and enterprise architects and how they must collaborate to create an SOA Understanding the need for a comprehensive total architecture approach that encompasses business processes, people, systems, data, and infrastructure Understanding the strategies and tradeoffs for implementing robust, secure, high-performance, and high-availability solutions Understanding how to incorporate business process management (BPM) and business process monitoring into the enterprise architecture Whether you’re defining an enterprise architecture or delivering individual SOA projects, this book will give you the practical advice you need to get the job done.

Table of Contents:
Preface        xxvii Part I: Fundamentals        1 Chapter 1: SOA and the Enterprise          3 The Challenge     4 The Concept of Total Architecture    5 Architecture Is Structure for a Purpose     6 Constant Changes    7 Total Architecture Synthesis        8 Making Total Architecture Work in Your Enterprise         9 Key Overview Questions    10 Chapter 2: Architecture Fundamentals        11 Structural Organization     11 Functional Organization    15 Collaborative Behavior     20 Total Architecture    26 Nonfunctional Requirements     27 Refinement    28 The Role of the Architect    29 Enterprise Architecture    30 Summary    34 Key Architecture Fundamentals Questions     35 Suggested Reading      36 Chapter 3: Service Fundamentals         37 What Is a Service?     37 Operations    38 Service Interfaces     47 The Rationale Behind Services    54 Summary    58 Key Service Fundamentals Questions    59 Suggested Reading    60 Chapter 4: Using Services        61 Service Interaction Patterns     61 Service Access         67 Access Control    72 Service Request Routing    76 Service Composition    80 Locating Services    85 Enterprise Architecture for Services    86 Summary    87 Key Service Utilization Questions    88 Suggested Reading     89 Chapter 5: The SOA Development Process         91 What Is Different about SOA Development?        91 The Overall Development Process    92 Architecture Tasks    94 Architecture in Context    96 Total Architecture Synthesis (TAS)    97 Beware of Look-Alike Processes!    105 Manage Risk: Architect Iteratively    106 Summary    108 Key Development Process Questions    108 Suggested Reading    109 Part II: The Business Process Perspective        111 Chapter 6: Processes        113 Triggers, Inputs, and Results        114 Related Processes    115 Process Maturity    116 Continuous Processes    119 Structured Processes     120 Summary     121 Key Process Questions     122 Suggested Reading    122 Chapter 7: Initial Project Scoping        123 Assembling the Business Process Inventory        124 Conducting Interviews    125 Documenting the Inventory    128 Ranking Business Processes    141 Organizing the Remaining Work    147 Summary    149 Key Scoping Questions    150 Chapter 8: The Artifice of Requirements        151 Differentiation        153 Characterizing Processes    159 Patterns of Interaction    163 Interaction Patterns Characterize Participants    171 Requirements Reflect Design        172 Summary    175 Key Requirements Questions        177 Suggested Reading    178 Chapter 9: Business Process Architecture        179 Results    180 Participants and Their Roles    182 Activities and Scenarios    186 Modeling Scenarios    191 Modeling Interactions        198 How Much Detail Is Enough?    204 Guidelines for Using Activity Diagrams    206 Summary    207 Key Business Process Architecture Questions    208 Suggested Reading    209 Chapter 10: Milestones        211 Basic Process Milestones    211 Variations in Milestone Sequences    214 Grouped Milestones    215 Recognizing Milestones Requires Design    216 Using Milestones to Reduce Inter-Process Coupling        217 Summary     218 Key Milestone Questions    219 Chapter 11: Process Constraints        221 Business Process Constraints Drive System Constraints    222 Performance Constraints     224 High Availability and Fault Tolerance    231 Security    238 Reporting, Monitoring, and Management    240 Exception Handling    242 Test and Acceptance    243 Compliance Constraints    245 Summary    246 Key Process Constraint Questions    247 Suggested Reading    248 Chapter 12: Related Processes        249 Identifying Services    252 Triggering Events    258 Summary    264 Key Related Process Questions    265 Chapter 13: Modeling the Domain     267 UML Class Notation    269 ATM Example Domain Model    274 Reverse Engineering the Domain Model    276 Domain Modeling Summary    277 Key Domain Modeling Questions    279 Suggested Reading    279 Chapter 14: Enterprise Architecture: Process and Domain Modeling        281 Process and Domain Modeling Responsibilities    282 Establishing Standards and Best Practices    283 Managing Process and Domain Knowledge Transfer         285 Reviewing Project Models     286 Maintaining the Business Process and Domain Model Repository    287 Defining Business Process Patterns     288 Defining Common Data Model Representations    288 Summary    289 Key Enterprise Process and Domain Modeling Questions     290 Part III: The Systems Perspective        291 Chapter 15: Systems Architecture Overview        293 The Challenge of Architecting Distributed Systems        294 Learning from the CORBA Experience    294 Efficiently Exploring Architectures     300 Summary    303 Key Systems Architecture Overview Questions      304 Chapter 16: Top-Level Systems Architecture        305 First-Cut Structure     305 Initial Evaluation    307 Communications and Modularization        309 Service Identification and Performance    312 Modeling System Interactions    312 Modeling Deployment    318 Addressing Performance    322 Early Architecture Evaluation        325 Key Top-Level Systems Architecture Questions    327 Suggested Reading    328 Part IV: Communications        329 Chapter 17: Transport         331 Transport Technology    332 Selecting Transports     336 Messaging Server Topology    340 Capacity     345 Point-to-Point Interaction Patterns    347 Point-to-Point Intermediaries    348 Transport-Supplied Services    350 Summary    351 Key Transport Questions      351 Suggested Reading    352 Chapter 18: Adapters    353 API-Based Adapters     354 Database-Based Adapters    355 Combining API and Database Approaches    356 File-Based Adapters    357 Protocol-Based Adapters    357 Documenting Adapter Usage    358 Summary    359 Key Adapter Questions     360 Chapter 19: Enterprise Architecture: Communications        361 Defining a Communications Strategy        361 Interaction Standards    362 Standardizing Adapters     363 Summary    364 Key Enterprise Architecture Communications Questions     364 Part V: Data and Operations        367 Chapter 20: Data Challenges        369 Chapter 21: Messages and Operations         371 Message Semantics and Operation Names     371 Transport Destinations and Operation Bundling     374 Content Representation    377 Content Transformation     378 Reference Data in Content Transformation    380 Summary    381 Key Messages and Operations Questions    381 Chapter 22: Data Consistency: Maintaining One Version of the Truth        383 Approaches to Maintaining Data Consistency    384 Cached Data with a Single System of Record        385 Coordinated Updates via Distributed Transactions    390 Edit Anywhere, Reconcile Later    390 Dealing with Data Inconsistencies      391 Data Management Business Processes    393 Summary    394 Key Data Consistency Questions      394 Suggested Reading    395 Chapter 23: Common Data Models (CDM)         397 What Is a Common Data Model?    397 CDM Relationship to the Domain Model      402 The Need for Multiple CDM Representations     405 Planning for CDM Changes    407 When to Use Common Data Models         411 Summary     415 Key Common Data Model Questions    416 Chapter 24: Identifiers (Unique Names)        417 Identity (Unique Name) Authorities    418 Hierarchical Identifiers    419 Coping with Identity Errors    423 Mapping Identifiers    429 Summary    433 Key Identifier Questions    434 Chapter 25: Results Validation     435 Checking Enumerated Values    436 Where and When to Validate    437 Summary    438 Key Data Validation Questions    439 Chapter 26: Enterprise Architecture: Data    441 Naming Schemes     441 Architecting Content Transformation    443 Systems of Record     445 Common Data Models     446 Identifiers     447 Data Quality Management    448 Summary      449 Key Enterprise Architecture Data Questions         450 Part VI: Coordination        451 Chapter 27: Coordination and Breakdown Detection         453 Activity Execution Management Patterns (AEMPs) Involving Interactions     454 Coordination Pattern Styles    456 Fire-and-Forget Coordination Patterns    457 Request-Reply Patterns    460 Delegation    465 Delegation with Confirmation        467 Summary    468 Key Coordination Questions        469 Chapter 28: Transactions: Coordinating Two or More Activities        471 Two-Phase Commit Distributed Transactions     472 Limitations of Two-Phase Commit Protocols    475 Compensating Transactions    476 Working around the Limitations of Compensating Transactions     476 Summary    478 Key Transaction Questions    479 Suggested Reading     479 Chapter 29: Process Monitors and Managers        481 Process Monitoring    483 Minimizing the Impact of Monitoring Breakdowns    484 The Process Manager as a Monitor    485 Process Management Limitations    486 Summary     488 Key Process Monitoring and Management Questions    488 Chapter 30: Detecting and Responding to Breakdowns        489 Selecting Coordination Patterns to Improve Breakdown Detection    489 Responding to Breakdowns     493 Summary    504 Key Breakdown Detection and Recovery Questions        505 Chapter 31: Enterprise Architecture: Coordination         507 Preferred Coordination Patterns    507 Breakdown Recording         509 Breakdown Annunciation    510 Recovery Processes     511 Summary    511 Key Enterprise Coordination Questions    512 Part VII: High Availability, Fault Tolerance, and Load Distribution         513 Chapter 32: High Availability and Fault Tolerance Fundamentals        515 Fault Tolerance Strategies    516 Failure Detection Strategies     517 Failover Management        519 Redirecting Clients    520 Summary    522 Key High-Availability and Fault Tolerance Questions    523 Chapter 33: Stateless and Stateful Failover        525 Stateless and Stateful Components    525 Stateless Failover    525 Saving Work in Progress through Coordination    526 Stateful Failover    528 Storage Replication    530 Summary    540 Key Failover Questions    541 Suggested Reading    541 Chapter 34: Multiple Component Failover         543 Intra-Site versus Inter-Site Failover    543 Clustering: An Intra-Site Failover Technique      545 Coordinating Peer Application Failover with Asynchronous Replication    546 Making a Business Process Fault-Tolerant    548 Summary    550 Key Multi-Component Failover Questions    551 Chapter 35: Workload Distribution         553 Work Assignment Strategies     553 Distribution Management and Work Completion    554 The Sequencing Problem    556 Access to Shared Persistent State    557 Geographic Workload Distribution    558 Summary    558 Key Workload Distribution Questions    559 Chapter 36: Enterprise Architecture: Fault Tolerance, High Availability, and Load Distribution         561 Business Process Categorization    563 Information Storage    565 Individual Component and Service Failover Patterns        565 Composite Patterns for FT and HA Services    566 Composite Patterns for FT and HA Business Processes    568 Summary    568 Key Enterprise Fault Tolerance, High-Availability, and Load Distribution Questions    569 Suggested Reading    569 Part VIII: Completing the Architecture        571 Chapter 37: Process Security        573 Security Information Classification    574 Identity and Authentication    574 Authorization    576 Encryption    579 Digital Signatures    580 Other Security-Related Requirements    580 Reference Data Servers and Performance    581 Trust Zones    582 Channel Enforcement         583 Zone Enforcement and Policy Agents    585 Multi-Zone Security    586 Summary    587 Key Security Questions    588 Suggested Reading     589 Chapter 38: Process Monitoring         591 Performance Monitoring    592 Monitoring Process Status    594 Supervisory Processes    595 The Impact of Monitoring on Performance    596 Summary    596 Key Process Monitoring Questions    597 Chapter 39: Architecture Evaluation        599 Usability    600 Performance    600 Cost and Schedule Feasibility        612 Observability    613 Ability to Evolve    613 Ability to Handle Stress Situations    614 Summary    615 Key Architecture Evaluation Questions     616 Suggested Reading    617 Chapter 40: Testing        619 Unit Testing, Test Harnesses, and Regression Testing    620 Integration Testing and Order of Assembly    621 Environments for Functional and System Testing    622 Performance Testing    623 Failure Mode Testing    627 Summary    628 Key Testing Questions    628 Part IX: Advanced Topics        631 Chapter 41: Representing a Complex Process        633 Eliding Communications Detail    634 Eliding Participant Activity Details    634 Eliding Supporting Participants    636 Abstracting Subprocesses    638 Summary    639 Key Complex Process Representation Questions     639 Chapter 42: Process Management and Workflow        641 Process Management     642 Styles of Work Assignment    647 Initiating Workflow    649 Making the Management Process Fault Tolerant    649 Human Interfaces     656 Related Processes    660 Prioritized Work    663 Dynamic Work Assignments    665 Dynamic Result and Process Definitions    666 Summary    668 Key Process Management and Workflow Questions     669 Suggested Reading     670 Chapter 43: The Enterprise Architecture Group         671 Half a Group Is Better than None—But Not Good Enough         672 Best Practice Development    672 Knowledge Transfer     673 Governance    675 Designing with Evolving Requirements    675 Summary    681 Key Enterprise Architecture Group Questions     682 Afterword         683 Focus Your Work    683 Seek the Expertise of Others     684 Be Pragmatic, But Consider the Long View     685 Index        687