Cloud Computing

Clouds are distributed technology platforms that leverage sophisticated technology innovations to provide highly scalable and resilient environments that can be remotely utilized by organizations in a multitude of powerful ways. To successfully build upon, integrate with, or even create a cloud environment requires an understanding of its common inner mechanics, architectural layers, and models, as well as an understanding of the business and economic factors that result from the adoption and real-world use of cloud-based services. In Cloud Computing: Concepts, Technology & Architecture, Thomas Erl, one of the world's top-selling IT authors, teams up with cloud computing experts and researchers to break down proven and mature cloud computing technologies and practices into a series of well-defined concepts, models, technology mechanisms, and technology architectures, all from an industry-centric and vendor-neutral point of view. In doing so, the book establishes concrete, academic coverage with a focus on structure, clarity, and well-defined building blocks for mainstream cloud computing platforms and solutions. Subsequent to technology-centric coverage, the book proceeds to establish business-centric models and metrics that allow for the financial assessment of cloud-based IT resources and their comparison to those hosted on traditional IT enterprise premises. Also provided are templates and formulas for calculating SLA-related quality-of-service values and numerous explorations of the SaaS, PaaS, and IaaS delivery models. With more than 260 figures, 29 architectural models, and 20 mechanisms, this indispensable guide provides a comprehensive education of cloud computing essentials that will never leave your side. "Cloud computing, more than most disciplines in IT, suffers from too much talk and not enough practice. Thomas Erl has written a timely book that condenses the theory and buttresses it with real-world examples that demystify this important technology. An important guidebook for your journey into the cloud." --Scott Morrison, Chief Technology Officer, Layer 7 Technologies "An excellent, extremely well-written, lucid book that provides a comprehensive picture of cloud computing, covering multiple dimensions of the subject. The case studies presented in the book provide a real-world, practical perspective on leveraging cloud computing in an organization. The book covers a wide range of topics, from technology aspects to the business value provided by cloud computing. This is the best, most comprehensive book on the subject--a must-read for any cloud computing practitioner or anyone who wants to get an in-depth picture of cloud computing concepts and practical implementation." --Suzanne D'Souza, SOA/BPM Practice Lead, KBACE Technologies "This book offers a thorough and detailed description of cloud computing concepts, architectures, and technologies. It serves as a great reference for both newcomers and experts and is a must-read for any IT professional interested in cloud computing." --Andre Tost, Senior Technical Staff Member, IBM Software Group "This is a great book on the topic of cloud computing. It is impressive how the content spans from taxonomy, technology, and architectural concepts to important business considerations for cloud adoption. It really does provide a holistic view to this technology paradigm." --Kapil Bakshi, Architecture and Strategy, Cisco Systems Inc. "I have read every book written by Thomas Erl and Cloud Computing is another excellent publication and demonstration of Thomas Erl's rare ability to take the most complex topics and provide critical core concepts and technical information in a logical and understandable way." --Melanie A. Allison, Principal, Healthcare Technology Practice, Integrated Consulting Services "Companies looking to migrate applications or infrastructure to the cloud are often misled by buzzwords and industry hype. This work cuts through the hype and provides a detailed look, from investigation to contract to implementation to termination, at what it takes for an organization to engage with cloud service providers. This book really lays out the benefits and struggles with getting a company to an IaaS, PaaS, or SaaS solution." --Kevin Davis, Ph.D., Solutions Architect "Thomas, in his own distinct and erudite style, provides a comprehensive and a definitive book on cloud computing. Just like his previous masterpiece, Service-Oriented Architecture: Concepts, Technology, and Design, this book is sure to engage CxOs, cloud architects, and the developer community involved in delivering software assets on the cloud. Thomas and his authoring team have taken great pains in providing great clarity and detail in documenting cloud architectures, cloud delivery models, cloud governance, and economics of cloud, without forgetting to explain the core of cloud computing that revolves around Internet architecture and virtualization. As a reviewer for this outstanding book, I must admit I have learned quite a lot while reviewing the material. A 'must have' book that should adorn everybody's desk!" --Vijay Srinivasan, Chief Architect - Technology, Cognizant Technology Solutions "This book provides comprehensive and descriptive vendor-neutral coverage of cloud computing technology, from both technical and business aspects. It provides a deep-down analysis of cloud architectures and mechanisms that capture the real-world moving parts of cloud platforms. Business aspects are elaborated on to give readers a broader perspective on choosing and defining basic cloud computing business models. Thomas Erl's Cloud Computing: Concepts, Technology & Architecture is an excellent source of knowledge of fundamental and in-depth coverage of cloud computing." --Masykur Marhendra Sukmanegara, Communication Media & Technology, Consulting Workforce Accenture "The richness and depth of the topics discussed are incredibly impressive. The depth and breadth of the subject matter are such that a reader could become an expert in a short amount of time." --Jamie Ryan, Solutions Architect, Layer 7 Technologies "Demystification, rationalization, and structuring of implementation approaches have always been strong parts in each and every one of Thomas Erl's books. This book is no exception. It provides the definitive, essential coverage of cloud computing and, most importantly, presents this content in a very comprehensive manner. Best of all, this book follows the conventions of the previous service technology series titles, making it read like a natural extension of the library. I strongly believe that this will be another bestseller from one of the top-selling IT authors of the past decade." --Sergey Popov, Senior Enterprise Architect SOA/Security, Liberty Global International "A must-read for anyone involved in cloud design and decision making! This insightful book provides in-depth, objective, vendor-neutral coverage of cloud computing concepts, architecture models, and technologies. It will prove very valuable to anyone who needs to gain a solid understanding of how cloud environments work and how to design and migrate solutions to clouds." --Gijs in 't Veld, Chief Architect, Motion10 "A reference book covering a wide range of aspects related to cloud providers and cloud consumers. If you would like to provide or consume a cloud service and need to know how, this is your book. The book has a clear structure to facilitate a good understanding of the various concepts of cloud." --Roger Stoffers, Solution Architect "Cloud computing has been around for a few years, yet there is still a lot of confusion around the term and what it can bring to developers and deployers alike. This book is a great way of finding out what's behind the cloud, and not in an abstract or high-level manner: It dives into all of the details that you'd need to know in order to plan for developing applications on cloud and what to look for when using applications or Foreword xxix Acknowledgments xxxiii CHAPTER 1: Introduction 1 1.1 Objectives of This Book 3 1.2 What This Book Does Not Cover 4 1.3 Who This Book Is For 4 1.4 How This Book Is Organized 4 1.5 Conventions 9 Symbols and Figures 9 Summary of Key Points 9 1.6 Additional Information 9 Updates, Errata, and Resources (www.servicetechbooks.com) 9 Referenced Specifications (www.servicetechspecs.com) 10 The Service Technology Magazine (www.servicetechmag.com) 10 International Service Technology Symposium (www.servicetechsymposium.com) 10 What Is Cloud? (www.whatiscloud.com) 10 What Is REST? (www.whatisrest.com) 10 Cloud Computing Design Patterns (www.cloudpatterns.org) 10 Service-Orientation (www.serviceorientation.com) 11 CloudSchool.com Certified Cloud (CCP) Professional (www.cloudschool.com) 11 SOASchool.com SOA Certified (SOACP) Professional (www.soaschool.com) 11 Notification Service 11 CHAPTER 2: Case Study Background 13 2.1 Case Study #1: ATN 14 Technical Infrastructure and Environment 14 Business Goals and New Strategy 15 Roadmap and Implementation Strategy 15 2.2 Case Study #2: DTGOV 16 Technical Infrastructure and Environment 17 Business Goals and New Strategy 18 Roadmap and Implementation Strategy 19 2.3 Case Study #3: Innovartus Technologies Inc 20 Technical Infrastructure and Environment 20 Business Goals and Strategy 20 Roadmap and Implementation Strategy 21 PART I: FUNDAMENTAL CLOUD COMPUTING CHAPTER 3: Understanding Cloud Computing 25 3.1 Origins and Influences 26 A Brief History 26 Definitions 27 Business Drivers 28 Capacity Planning 28 Cost Reduction 29 Organizational Agility 30 Technology Innovations 30 Clustering 31 Grid Computing 31 Virtualization 32 Technology Innovations vs. Enabling Technologies 32 3.2 Basic Concepts and Terminology 33 Cloud 33 IT Resource 34 On-Premise 36 Cloud Consumers and Cloud Providers 36 Scaling 37 Horizontal Scaling 37 Vertical Scaling 37 Cloud Service 38 Cloud Service Consumer 40 3.3 Goals and Benefits 40 Reduced Investments and Proportional Costs 41 Increased Scalability 42 Increased Availability and Reliability 43 3.4 Risks and Challenges 45 Increased Security Vulnerabilities 45 Reduced Operational Governance Control 45 Limited Portability Between Cloud Providers 47 Multi-Regional Compliance and Legal Issues 48 CHAPTER 4: Fundamental Concepts and Models 51 4.1 Roles and Boundaries 52 Cloud Provider 52 Cloud Consumer 52 Cloud Service Owner 53 Cloud Resource Administrator 54 Additional Roles 56 Organizational Boundary 56 Trust Boundary 57 4.2 Cloud Characteristics 58 On-Demand Usage 59 Ubiquitous Access 59 Multitenancy (and Resource Pooling) 59 Elasticity 61 Measured Usage 61 Resiliency 61 4.3 Cloud Delivery Models 63 Infrastructure-as-a-Service (IaaS) 64 Platform-as-a-Service (PaaS) 65 Software-as-a-Service (SaaS) 66 Comparing Cloud Delivery Models 67 Combining Cloud Delivery Models 69 IaaS + PaaS 69 IaaS + PaaS + SaaS 72 4.4 Cloud Deployment Models 73 Public Clouds 73 Community Clouds 74 Private Clouds 75 Hybrid Clouds 77 Other Cloud Deployment Models 78 CHAPTER 5: Cloud-Enabling Technology 79 5.1 Broadband Networks and Internet Architecture 80 Internet Service Providers (ISPs) 80 Connectionless Packet Switching (Datagram Networks) 83 Router-Based Interconnectivity 83 Physical Network 84 Transport Layer Protocol 84 Application Layer Protocol 85 Technical and Business Considerations 85 Connectivity Issues 85 Network Bandwidth and Latency Issues 88 Cloud Carrier and Cloud Provider Selection 89 5.2 Data Center Technology 90 Virtualization 90 Standardization and Modularity 90 Automation 91 Remote Operation and Management 92 High Availability 92 Security-Aware Design, Operation, and Management 92 Facilities 92 Computing Hardware 93 Storage Hardware 93 Network Hardware 95 Carrier and External Networks Interconnection 95 Web-Tier Load Balancing and Acceleration 95 LAN Fabric 95 SAN Fabric 95 NAS Gateways 95 Other Considerations 96 5.3 Virtualization Technology 97 Hardware Independence 98 Server Consolidation 98 Resource Replication 98 Operating System-Based Virtualization 99 Hardware-Based Virtualization 101 Virtualization Management 102 Other Considerations 102 5.4 Web Technology 103 Basic Web Technology 104 Web Applications 104 5.5 Multitenant Technology 106 5.6 Service Technology 108 Web Services 109 REST Services 110 Service Agents 111 Service Middleware 112 5.7 Case Study Example 113 CHAPTER 6: Fundamental Cloud Security 117 6.1 Basic Terms and Concepts 118 Confidentiality 118 Integrity 119 Authenticity 119 Availability 119 Threat 120 Vulnerability 120 Risk 120 Security Controls 120 Security Mechanisms 121 Security Policies 121 6.2 Threat Agents 121 Anonymous Attacker 122 Malicious Service Agent 123 Trusted Attacker 123 Malicious Insider 123 6.3 Cloud Security Threats 124 Traffic Eavesdropping 124 Malicious Intermediary 124 Denial of Service 126 Insufficient Authorization 127 Virtualization Attack 127 Overlapping Trust Boundaries 129 6.4 Additional Considerations 131 Flawed Implementations 131 Security Policy Disparity 132 Contracts 132 Risk Management 133 6.5 Case Study Example 135 PART II: CLOUD COMPUTING MECHANISMS CHAPTER 7: Cloud Infrastructure Mechanisms 139 7.1 Logical Network Perimeter 140 Case Study Example 142 7.2 Virtual Server 144 Case Study Example 145 7.3 Cloud Storage Device 149 Cloud Storage Levels 149 Network Storage Interfaces 150 Object Storage Interfaces 151 Database Storage Interfaces 151 Relational Data Storage 151 Non-Relational Data Storage 152 Case Study Example 152 7.4 Cloud Usage Monitor 155 Monitoring Agent 155 Resource Agent 155 Polling Agent 157 Case Study Example 157 7.5 Resource Replication 161 Case Study Example 162 7.6 Ready-Made Environment 166 Case Study Example 167 CHAPTER 8: Specialized Cloud Mechanisms 169 8.1 Automated Scaling Listener 170 Case Study Example 172 8.2 Load Balancer 176 Case Study Example 177 8.3 SLA Monitor 178 Case Study Example 180 SLA Monitor Polling Agent 180 SLA Monitoring Agent 180 8.4 Pay-Per-Use Monitor 184 Case Study Example 187 8.5 Audit Monitor 189 Case Study Example 189 8.6 Failover System 191 Active-Active 191 Active-Passive 194 Case Study Example 196 8.7 Hypervisor 200 Case Study Example 201 8.8 Resource Cluster 203 Case Study Example 206 8.9 Multi-Device Broker 208 Case Study Example 209 8.10 State Management Database 210 Case Study Example 211 CHAPTER 9: Cloud Management Mechanisms 213 9.1 Remote Administration System 214 Case Study Example 219 9.2 Resource Management System 219 Case Study Example 221 9.3 SLA Management System 222 Case Study Example 224 9.4 Billing Management System 225 Case Study Example 227 CHAPTER 10: Cloud Security Mechanisms 229 10.1 Encryption 230 Symmetric Encryption 231 Asymmetric Encryption 231 Case Study Example 233 10.2 Hashing 234 Case Study Example 235 10.3 Digital Signature 236 Case Study Example 238 10.4 Public Key Infrastructure (PKI) 240 Case Study Example 242 10.5 Identity and Access Management (IAM) 243 Case Study Example 244 10.6 Single Sign-On (SSO) 244 Case Study Example 246 10.7 Cloud-Based Security Groups 247 Case Study Example 249 10.8 Hardened Virtual Server Images 251 Case Study Example 252 PART III: CLOUD COMPUTING ARCHITECTURE CHAPTER 11: Fundamental Cloud Architectures 255 11.1 Workload Distribution Architecture 256 11.2 Resource Pooling Architecture 257 11.3 Dynamic Scalability Architecture 262 11.4 Elastic Resource Capacity Architecture 265 11.5 Service Load Balancing Architecture 268 11.6 Cloud Bursting Architecture 271 11.7 Elastic Disk Provisioning Architecture 272 11.8 Redundant Storage Architecture 275 11.9 Case Study Example 277 CHAPTER 12: Advanced Cloud Architectures 281 12.1 Hypervisor Clustering Architecture 282 12.2 Load Balanced Virtual Server Instances Architecture 288 12.3 Non-Disruptive Service Relocation Architecture 293 12.4 Zero Downtime Architecture 298 12.5 Cloud Balancing Architecture 299 12.6 Resource Reservation Architecture 301 12.7 Dynamic Failure Detection and Recovery Architecture 306 12.8 Bare-Metal Provisioning Architecture 309 12.9 Rapid Provisioning Architecture 312 12.10 Storage Workload Management Architecture 315 12.11 Case Study Example 321 CHAPTER 13: Specialized Cloud Architectures 323 13.1 Direct I/O Access Architecture 324 13.2 Direct LUN Access Architecture 326 13.3 Dynamic Data Normalization Architecture 329 13.4 Elastic Network Capacity Architecture 330 13.5 Cross-Storage Device Vertical Tiering Architecture 332 13.6 Intra-Storage Device Vertical Data Tiering Architecture 337 13.7 Load Balanced Virtual Switches Architecture 340 13.8 Multipath Resource Access Architecture 342 13.9 Persistent Virtual Network Configuration Architecture 344 13.10 Redundant Physical Connection for Virtual Servers Architecture 347 13.11 Storage Maintenance Window Architecture 350 PART IV: WORKING WITH CLOUDS CHAPTER 14: Cloud Delivery Model Considerations 359 14.1 Cloud Delivery Models: The Cloud Provider Perspective 360 Building IaaS Environments 360 Data Centers 361 Scalability and Reliability 363 Monitoring 363 Security 364 Equipping PaaS Environments 364 Scalability and Reliability 365 Monitoring 367 Security 367 Optimizing SaaS Environments 367 Security 370 14.2 Cloud Delivery Models: The Cloud Consumer Perspective 370 Working with IaaS Environments 370 IT Resource Provisioning Considerations 372 Working with PaaS Environments 373 IT Resource Provisioning Considerations 373 Working with SaaS Services 374 14.3 Case Study Example 375 CHAPTER 15: Cost Metrics and Pricing Models 379 15.1 Business Cost Metrics 380 Up-Front and On-Going Costs 380 Additional Costs 381 Case Study Example 382 Product Catalog Browser 382 On-Premise Up-Front Costs 382 On-Premise On-Going Costs 383 Cloud-Based Up-Front Costs 383 Cloud-Based On-Going Costs 383 Client Database 385 On-Premise Up-Front Costs 385 On-Premise On-Going Costs 385 Cloud-Based Up-Front Costs 385 Cloud-Based On-Going Costs 385 15.2 Cloud Usage Cost Metrics 387 Network Usage 387 Inbound Network Usage Metric 387 Outbound Network Usage Metric 388 Intra-Cloud WAN Usage Metric 388 Server Usage 389 On-Demand Virtual Machine Instance Allocation Metric 389 Reserved Virtual Machine Instance Allocation Metric 389 Cloud Storage Device Usage 390 On-Demand Storage Space Allocation Metric 390 I/O Data Transferred Metric 390 Cloud Service Usage 390 Application Subscription Duration Metric 390 Number of Nominated Users Metric 391 Number of Transactions Users Metric 391 15.3 Cost Management Considerations 391 Pricing Models 393 Additional Considerations 395 Case Study Example 396 Virtual Server On-Demand Instance Allocation 397 Virtual Server Reserved Instance Allocation 399 Cloud Storage Device 401 WAN Traffic 401 CHAPTER 16: Service Quality Metrics and SLAs 403 16.1 Service Quality Metrics 404 Service Availability Metrics 405 Availability Rate Metric 405 Outage Duration Metric 406 Service Reliability Metrics 407 Mean-Time Between Failures (MTBF) Metric 407 Reliability Rate Metric 407 Service Performance Metrics 407 Network Capacity Metric 408 Storage Device Capacity Metric 408 Server Capacity Metric 408 Web Application Capacity Metric 408 Instance Starting Time Metric 409 Response Time Metric 409 Completion Time Metric 409 Service Scalability Metrics 409 Storage Scalability (Horizontal) Metric 410 Server Scalability (Horizontal) Metric 410 Server Scalability (Vertical) Metric 410 Service Resiliency Metrics 411 Mean-Time to Switchover (MTSO) Metric 411 Mean-Time System Recovery (MTSR) Metric 412 16.2 Case Study Example 412 16.3 SLA Guidelines 413 16.4 Case Study Example 416 Scope and Applicability 416 Service Quality Guarantees 416 Definitions 417 Usage of Financial Credits 417 SLA Exclusions 418 PART V: APPENDICES Appendix A: Case Study Conclusions 421 A.1 ATN 422 A.2 DTGOV 422 A.3 Innovartus 424 Appendix B: Industry Standards Organizations 427 B.1 National Institute of Standards and Technology (NIST) 428 B.2 Cloud Security Alliance (CSA) 429 B.3 Distributed Management Task Force (DMTF) 429 B.4 Storage Networking Industry Association (SNIA) 430 B.5 Organization for the Advancement of Structured Information Standards (OASIS) 430 B.6 The Open Group 430 B.7 Open Cloud Consortium (OCC) 431 B.8 European Telecommunications Standards Institute (ETSI) 431 B.9 Telecommunications Industry Association (TIA) 431 B.10 Liberty Alliance 432 B.11 Open Grid Forum (OGF) 432 Appendix C: Mapping Mechanisms to Characteristics 433 Appendix D: Data Center Facilities (TIA-942) 437 D.1 Primary Rooms 438 Electrical Room 438 Mechanical Room 438 Storage and Staging 438 Offices, Operations Center, and Support 438 Telecommunications Entrance 438 Computer Room 439 D.2 Environmental Controls 440 External Electrical Power Provider Interconnection 440 Power Distribution 441 Uninterruptible Power Source (UPS) 441 Power Engine-Generator 441 D.3 Infrastructure Redundancy Summary 442 Appendix E: Emerging Technologies 443 E.1 Autonomic Computing 444 E.2 Grid Computing 445 Service Grids 446 Appendix F: Cloud Provisioning Contracts 449 F.1 Cloud Provisioning Contract Structure 450 Terms of Service 452 Service Usage Policy 452 Security and Privacy Policy 453 Warranties and Liabilities 455 Rights and Responsibilities 455 Termination and Renewal 456 Specifications and SLAs 456 Pricing and Billing 457 Other Issues 457 Legal and Compliance Issues 457 Auditability and Accountability 457 Changes in the Contract Terms and Conditions 457 F.2 Cloud Provider Selection Guidelines 458 Cloud Provider Viability 458 Appendix G: Cloud Business Case Template 461 G.1 Business Case Identification 462 G.2 Business Needs 462 G.3 Target Cloud Environment 463 G.4 Technical Issues 464 G.5 Economic Factors 464 About the Authors 465 About the Foreword Contributor 467 About the Contributors 469 Index 471