分布式系统 原理与范型PDF电子书下载

1 INTRODUCTION 1

1.1 DEFINITION OF A DISTRIBUTED SYSTEM 2

1.2 GOALS 3

1.2.1 Making Resources Accessible 3

1.2.2 Distribution Transparency 4

1.2.3 Openness 7

1.2.4 Scalability 9

1.2.5 Pitfalls 16

1.3 TYPES OF DISTRIBUTED SYSTEMS 17

1.3.1 Distributed Computing Systems 17

1.3.2 Distributed Information Systems 20

1.3.3 Distributed Pervasive Systems 24

1.4 SUMMARY 30

2 ARCHITECTURES 33

2.1 ARCHITECTURAL STYLES 34

2.2 SYSTEM ARCHITECTURES 36

2.2.1 Centralized Architectures 36

2.2.2 Decentralized Architectures 43

2.2.3 Hybrid Architectures 52

2.3 ARCHITECTURES VERSUS MIDDLEWARE 54

2.3.1 Interceptors 55

2.3.2 General Approaches to Adaptive Software 57

2.3.3 Discussion 58

2.4 SELF-MANAGEMENT IN DISTRIBUTED SYSTEMS 59

2.4.1 The Feedback Control Model 60

2.4.2 Example：Systems Monitoring with Astrolabe 61

2.4.3 Example：Differentiating Replication Strategies in Globule 63

2 4.4 Example：Automatic Component Repair Management in Jade 65

2.5 SUMMARY 66

3 PROCESSES 69

3.1 THREADS 70

3.1.1 Introduction to Threads 70

3.1.2 Threads in Distributed Systems 75

3.2 VIRTUALIZATION 79

3.2.1 The Role of Virtualization in Distributed Systems 79

3.2.2 Architectures of Virtual Machines 80

3.3 CLIENTS 82

3.3.1 Networked User Interfaces 82

3.3.2 Client-Side Software for Distribution Transparency 87

3.4 SERVERS 88

3.4.1 General Design Issues 88

3.4.2 Server Clusters 92

3.4.3 Managing Server Clusters 98

3.5 CODE MIGRATION 103

3.5.1 Approaches to Code Migration 103

3.5.2 Migration and Local Resources 107

3.5.3 Migration in Heterogeneous Systems 110

3.6 SUMMARY 112

4 COMMUNICATION 115

4.1 FUNDAMENTALS 116

4.1.1 Layered Protocols 116

4.1.2 Types of Communication 124

4.2 REMOTE PROCEDURE CALL 125

4.2.1 Basic RPC Operation 126

4.2.2 Parameter Passing 130

4.2.3 Asynchronous RPC 134

4.2.4 Example：DCE RPC 135

4.3 MESSAGE-ORIENTED COMMUNICATION 140

4.3.1 Message-Oriented Transient Communication 141

4.3.2 Message-Oriented Persistent Communication 145

4.3.3 Example：IBM's WebSphere Message-Queuing System 152

4.4 STREAM-ORIENTED COMMUNICATION 157

4.4.1 Support for Continuous Media 158

4.4.2 Streams and Quality of Service 160

4.4.3 Stream Synchronization 163

4.5 MULTICAST COMMUNICATION 166

4.5.1 Application-Level Multicasting 166

4.5.2 Gossip-Based Data Dissemination 170

4.6 SUMMARY 175

5 NAMING 179

5.1 NAMES,IDENTIFIERS,AND ADDRESSES 180

5.2 FLAT NAMING 182

5.2.1 Simple Solutions 183

5.2.2 Home-Based Approaches 186

5.2.3 Distributed Hash Tables 188

5.2.4 Hierarchical Approaches 191

5.3 STRUCTURED NAMING 195

5.3.1 Name Spaces 195

5.3.2 Name Resolution 198

5.3.3 The Implementation of a Name Space 202

5.3.4 Example：The Domain Name System 209

5.4 ATTRIBUTE-BASED NAMING 217

5.4.1 Directory Services 217

5.4.2 Hierarchical Implementations：LDAP 218

5.4.3 Decentralized Implementations 222

5.5 SUMMARY 231

6 SYNCHRONIZATION 231

6.1 CLOCK SYNCHRONIZATION 232

6.1.1 Physical Clocks 233

6.1.2 Global Positioning System 236

6.1.3 Clock Synchronization Algorithms 238

6.2 LOGICAL CLOCKS 244

6.2.1 Lamport's Logical Clocks 244

6.2.2 Vector Clocks 248

6.3 MUTUAL EXCLUSION 252

6.3.1 Overview 252

6.3.2 A Centralized Algorithm 253

6.3.3 A Decentralized Algorithm 254

6.3.4 A Distributed Algorithm 255

6.3.5 A Token Ring Algorithm 258

6.3.6 A Comparison of the Four Algorithms 259

6.4 GLOBAL POSITIONING OF NODES 260

6.5 ELECTION ALGORITHMS 263

6.5.1 Traditional Election Algorithms 264

6.5.2 Elections in Wireless Environments 267

6.5.3 Elections in Large-Scale Systems 269

6.6 SUMMARY 270

7 CONSISTENCY AND REPLICATION 273

7.1 INTRODUCTION 274

7.1.1 Reasons for Replication 274

7.1.2 Replication as Scaling Technique 275

7.2 DATA-CENTRIC CONSISTENCY MODELS 276

7.2.1 Continuous Consistency 277

7.2.2 Consistent Ordering of Operations 281

7.3 CLIENT-CENTRIC CONSISTENCY MODELS 288

7.3.1 Eventual Consistency 289

7.3.2 Monotonic Reads 291

7.3.3 Monotonic Writes 292

7.3.4 Read Your Writes 294

7.3.5 Writes Follow Reads 295

7.4 REPLICA MANAGEMENT 296

7.4.1 Replica-Server Placement 296

7.4.2 Content Replication and Placement 298

7.4.3 Content Distribution 302

7.5 CONSISTENCY PROTOCOLS 306

7.5.1 Continuous Consistency 306

7.5.2 Primary-Based Protocols 308

7.5.3 Replicated-Write Protocols 311

7.5.4 Cache-Coherence Protocols 313

7.5.5 Implementing Client-Centric Consistency 315

7.6 SUMMARY 317

8 FAULT TOLERANCE 321

8.1 INTRODUCTION TO FAULT TOLERANCE 322

8.1.1 Basic Concepts 322

8.1.2 Failure Models 324

8.1.3 Failure Masking by Redundancy 326

8.2 PROCESS RESILIENCE 328

8.2.1 Design Issues 328

8.2.2 Failure Masking and Replication 330

8.2.3 Agreement in Faulty Systems 331

8.2.4 Failure Detection 335

8.3 RELIABLE CLIENT-SERVER COMMUNICATION 336

8.3.1 Point-to-Point Communication 337

8.3.2 RPC Semantics in the Presence of Failures 337

8.4 RELIABLE GROUP COMMUNICATION 343

8.4.1 Basic Reliable-Multicasting Schemes 343

8.4.2 Scalability in Reliable Multicasting 345

8.4.3 Atomic Multicast 348

8.5 DISTRIBUTED COMMIT 355

8.5.1 Two-Phase Commit 355

8.5.2 Three-Phase Commit 360

8.6 RECOVERY 363

8.6.I Introduction 363

8.6.2 Checkpointing 366

8.6.3 Message Logging 369

8.6.4 Recovery-Oriented Computing 372

8.7 SUMMARY 373

9 SECURITY 377

9.1 INTRODUCTION TO SECURITY 378

9.1.1 Security Threats,Policies,and Mechanisms 378

9.1.2 Design Issues 384

9.1.3 Cryptography 389

9.2 SECURE CHANNELS 396

9.2.1 Authentication 397

9.2.2 Message Integrity and Confidentiality 405

9.2.3 Secure Group Communication 408

9.2.4 Example：Kerberos 411

9.3 ACCESS CONTROL 413

9.3.1 General Issues in Access Control 414

9.3.2 Firewalls 418

9.3.3 Secure Mobile Code 420

9.3.4 Denial of Service 427

9.4 SECURITY MANAGEMENT 428

9.4.1 Key Management 428

9.4.2 Secure Group Management 433

9.4.3 Authorization Management 434

9.5 SUMMARY 439

10 DISTRIBUTED OBJECT-BASED SYSTEMS 443

10.1 ARCHITECTURE 443

10.1.1 Distributed Objects 444

10.1.2 Example：Enterprise Java Beans 446

10.1.3 Example：Globe Distributed Shared Objects 448

10.2 PROCESSES 451

10.2.1 Object Servers 451

10.2.2 Example：The Ice Runtime System 454

10.3 COMMUNICATION 456

10.3.1 Binding a Client to an Object 456

10.3.2 Static versus Dynamic Remote Method Invocations 458

10.3.3 Parameter Passing 460

10.3.4 Example：Java RMI 461

10.3.5 Object-Based Messaging 464

10.4 NAMING 466

10.4.1 CORBA Object References 467

10.4.2 Globe Object References 469

10.5 SYNCHRONIZATION 470

10.6 CONSISTENCY AND REPLICATION 472

10.6.1 Entry Consistency 472

10.6.2 Replicated Invocations 475

10.7 FAULT TOLERANCE 477

10.7.1 Example：Fault-Tolerant CORBA 477

10.7.2 Example：Fault-Tolerant Java 480

10.8 SECURITY 481

10.8.1 Example：Globe 482

10.8.2 Security for Remote Objects 486

10.9 SUMMARY 487

11 DISTRIBUTED FILE SYSTEMS 491

11.1 ARCHITECTURE 491

11.1.1 Client-Server Architectures 491

11.1.2 Cluster-Based Distributed File Systems 496

11.1.3 Symmetric Architectures 499

11.2 PROCESSES 501

11.3 COMMUNICATION 502

11.3.1 RPCs in NFS 502

11.3.2 The RPC2 Subsystem 503

11.3.3 File-Oriented Communication in Plan 9 505

11.4 NAMING 506

11.4.1 Naming in NFS 506

11.4.2 Constructing a Giobal Name Space 512

11.5 SYNCHRONIZATION 513

11.5.1 Semantics of File Sharing 513

11.5.2 File Locking 516

11.5.3 Sharing Files in Coda 518

11.6 CONSISTENCY AND REPLICATION 519

11.6.1 Client-Side Caching 520

11.6.2 Server-Side Replication 524

11.6.3 Replication in Peer-to-Peer File Systems 526

11.6.4 File Replication in Grid Systems 528

11.7 FAULT TOLERANCE 529

11.7.1 Handling Byzantine Failures 529

11.7.2 High Availability in Peer-to-Peer Systems 531

11.8 SECURITY 532

11.8.1 Security in NFS 533

11.8.2 Decentralized Authentication 536

11.8.3 Secure Peer-to-Peer File-Sharing Systems 539

11.9 SUMMARY 541

12 DISTRIBUTED WEB-BASED SYSTEMS 545

12.1 ARCHITECTURE 546

12.1.1 Traditional Web-Based Systems 546

12.1.2 Web Services 551

12.2 PROCESSES 554

12.2.1 Clients 554

12.2.2 The Apache Web Server 556

12.2.3 Web Server Clusters 558

12.3 COMMUNICATION 560

12.3.1 Hypertext Transfer Protocol 560

12.3.2 Simple Object Access Protocol 566

12.4 NAMING 567

12.5 SYNCHRONIZATION 569

12.6 CONSISTENCY AND REPLICATION 570

12.6.1 Web Proxy Caching 571

12.6.2 Replication for Web Hosting Systems 573

12.6.3 Replication of Web Applications 579

12.7 FAULT TOLERANCE 582

12.8 SECURITY 584

12.9 SUMMARY 585

13 DISTRIBUTED COORDINATION-BASED SYSTEMS 589

13.1 INTRODUCTION TO COORDINATION MODELS 589

13.2 ARCHITECTURES 591

13.2.1 Overall Approach 592

13.2.2 Traditional Architectures 593

13.2.3 Peer-to-Peer Architectures 596

13.2.4 Mobility and Coordination 599

13.3 PROCESSES 601

13.4 COMMUNICATION 601

13.4.1 Content-Based Routing 601

13.4.2 Supporting Composite Subscriptions 603

13.5 NAMING 604

13.5.1 Describing Composite Events 604

13.5.2 Matching Events and Subscriptions 606

13.6 SYNCHRONIZATION 607

13.7 CONSISTENCY AND REPLICATION 607

13.7.1 Static Approaches 608

13.7.2 Dynamic Replication 611

13.8 FAULT TOLERANCE 613

13.8.1 Reliable Publish-Subscribe Communication 613

13.8.2 Fault Tolerance in Shared Dataspaces 616

13.9 SECURITY 617

13.9.1 Confidentiality 618

13.9.2 Secure Shared Dataspaces 620

13.10 SUMMARY 621

14 SUGGESTIONS FOR FURTHER READING AND BIBUOGRAPHY 623

14.1 SUGGESTIONS FOR FURTHER READING 623

14.1.1 Introduction and General Works 623

14.1.2 Architectures 624

14.1.3 Processes 625

14.1.4 Communication 626

14.1.5 Naming 626

14.1.6 Synchronization 627

14.1.7 Consistency and Replication 628

14.1.8 Fault Tolerance 629

14.1.9 Security 630

14.1.10 Distributed Object-Based Systems 631

14.1.11 Distributed File Systems 632

14.1.12 Distributed Web-Based Systems 632

14.1.13 Distributed Coordination-Based Systems 633

14.2 ALPHABETICAL BIBLIOGRAPHY 634

INDEX 669