A holistic approach to service reliability and availability of cloud computing
Reliability and Availability of Cloud Computing provides IS/IT system and solution architects, developers, and engineers with the knowledge needed to assess the impact of virtualization and cloud computing on service reliability and availability. It reveals how to select the most appropriate design for reliability diligence to assure that user expectations are met.
Organized in three parts (basics, risk analysis, and recommendations), this resource is accessible to readers of diverse backgrounds and experience levels. Numerous examples and more than 100 figures throughout the book help readers visualize problems to better understand the topic—and the authors present risks and options in bulleted lists that can be applied directly to specific applications/problems.
Special features of this book include:
- Rigorous analysis of the reliability and availability risks that are inherent in cloud computing
- Simple formulas that explain the quantitative aspects of reliability and availability
- Enlightening discussions of the ways in which virtualized applications and cloud deployments differ from traditional system implementations and deployments
- Specific recommendations for developing reliable virtualized applications and cloud-based solutions
Reliability and Availability of Cloud Computing is the guide for IS/IT staff in business, government, academia, and non-governmental organizations who are moving their applications to the cloud. It is also an important reference for professionals in technical sales, product management, and quality management, as well as software and quality engineers looking to broaden their expertise.
Figures xvii Tables xxi Equations xxiii Introduction xxv I BASICS 1
1 CLOUD COMPUTING 3 1.1 Essential Cloud Characteristics 4 1.2 Common
Cloud Characteristics 6 1.3 But What, Exactly, Is Cloud Computing? 7 1.4
Service Models 9 1.5 Cloud Deployment Models 11 1.6 Roles in Cloud
Computing 12 1.7 Benefi ts of Cloud Computing 14 1.8 Risks of Cloud
Computing 15 2 VIRTUALIZATION 16 2.1 Background 16 2.2 What Is
Virtualization? 17 2.3 Server Virtualization 19 2.4 VM Lifecycle 23 2.5
Reliability and Availability Risks of Virtualization 28 3 SERVICE
RELIABILITY AND SERVICE AVAILABILITY 29 3.1 Errors and Failures 30 3.2
Eight-Ingredient Framework 31 3.3 Service Availability 34 3.4 Service
Reliability 43 3.5 Service Latency 46 3.6 Redundancy and High Availability
50 3.7 High Availability and Disaster Recovery 56 3.8 Streaming Services 58
3.9 Reliability and Availability Risks of Cloud Computing 62 II ANALYSIS
63 4 ANALYZING CLOUD RELIABILITY AND AVAILABILITY 65 4.1 Expectations
for Service Reliability and Availability 65 4.2 Risks of Essential Cloud
Characteristics 66 4.3 Impacts of Common Cloud Characteristics 70 4.4 Risks
of Service Models 72 4.5 IT Service Management and Availability Risks 74
4.6 Outage Risks by Process Area 80 4.7 Failure Detection Considerations 83
4.8 Risks of Deployment Models 87 4.9 Expectations of IaaS Data Centers 87
5 RELIABILITY ANALYSIS OF VIRTUALIZATION 90 5.1 Reliability Analysis
Techniques 90 5.2 Reliability Analysis of Virtualization Techniques 95 5.3
Software Failure Rate Analysis 100 5.4 Recovery Models 101 5.5 Application
Architecture Strategies 108 5.6 Availability Modeling of Virtualized
Recovery Options 110 6 HARDWARE RELIABILITY, VIRTUALIZATION, AND SERVICE
AVAILABILITY 116 6.1 Hardware Downtime Expectations 116 6.2 Hardware
Failures 117 6.3 Hardware Failure Rate 119 6.4 Hardware Failure Detection
121 6.5 Hardware Failure Containment 122 6.6 Hardware Failure Mitigation
122 6.7 Mitigating Hardware Failures via Virtualization 124 6.8 Virtualized
Networks 127 6.9 MTTR of Virtualized Hardware 129 6.10 Discussion 131 7
CAPACITY AND ELASTICITY 132 7.1 System Load Basics 132 7.2 Overload,
Service Reliability, and Service Availability 135 7.3 Traditional Capacity
Planning 136 7.4 Cloud and Capacity 137 7.5 Managing Online Capacity 144
7.6 Capacity-Related Service Risks 147 7.7 Capacity Management Risks 153
7.8 Security and Service Availability 157 7.9 Architecting for Elastic
Growth and Degrowth 162 8 SERVICE ORCHESTRATION ANALYSIS 164 8.1 Service
Orchestration Definition 164 8.2 Policy-Based Management 166 8.3 Cloud
Management 168 8.4 Service Orchestration's Role in Risk Mitigation 169 9
GEOGRAPHIC DISTRIBUTION, GEOREDUNDANCY, AND DISASTER RECOVERY 174 9.1
Geographic Distribution versus Georedundancy 175 9.2 Traditional Disaster
Recovery 175 9.3 Virtualization and Disaster Recovery 177 9.4 Cloud
Computing and Disaster Recovery 178 9.5 Georedundancy Recovery Models 180
9.6 Cloud and Traditional Collateral Benefits of Georedundancy 180 9.7
Discussion 182 III RECOMMENDATIONS 183 10 APPLICATIONS, SOLUTIONS, AND
ACCOUNTABILITY 185 10.1 Application Configuration Scenarios 185 10.2
Application Deployment Scenario 187 10.3 System Downtime Budgets 188 10.4
End-to-End Solutions Considerations 197 10.5 Attributability for Service
Impairments 201 10.6 Solution Service Measurement 204 10.7 Managing
Reliability and Service of Cloud Computing 207 11 RECOMMENDATIONS FOR
ARCHITECTING A RELIABLE SYSTEM 209 11.1 Architecting for Virtualization and
Cloud 209 11.2 Disaster Recovery 216 11.3 IT Service Management
Considerations 217 11.4 Many Distributed Clouds versus Fewer Huge Clouds 224
11.5 Minimizing Hardware-Attributed Downtime 225 11.6 Architectural
Optimizations 231 12 DESIGN FOR RELIABILITY OF VIRTUALIZED APPLICATIONS 244
12.1 Design for Reliability 244 12.2 Tailoring DfR for Virtualized
Applications 246 12.3 Reliability Requirements 248 12.4 Qualitative
Reliability Analysis 256 12.5 Quantitative Reliability Budgeting and
Modeling 259 12.6 Robustness Testing 260 12.7 Stability Testing 267 12.8
Field Performance Analysis 268 12.9 Reliability Roadmap 269 12.10 Hardware
Reliability 270 13 DESIGN FOR RELIABILITY OF CLOUD SOLUTIONS 271 13.1
Solution Design for Reliability 271 13.2 Solution Scope and Expectations 273
13.3 Reliability Requirements 275 13.4 Solution Modeling and Analysis 279
13.5 Element Reliability Diligence 285 13.6 Solution Testing and Validation
285 13.7 Track and Analyze Field Performance 288 13.8 Other Solution
Reliability Diligence Topics 292 14 SUMMARY 296 14.1 Service Reliability
and Service Availability 297 14.2 Failure Accountability and Cloud Computing
299 14.3 Factoring Service Downtime 301 14.4 Service Availability
Measurement Points 303 14.5 Cloud Capacity and Elasticity Considerations 306
14.6 Maximizing Service Availability 306 14.7 Reliability Diligence 309
14.8 Concluding Remarks 310 Abbreviations 311 References 314 About the
Authors 318 Index 319
ERIC BAUER is a reliability engineering manager in the Software, Solutions and Services Group of Alcatel-Lucent. The holder of more than a dozen U.S. patents, he is the author of Design for Reliability: Information and Computer-Based Systems, Beyond Redundancy: How Geographic Redundancy Can Improve Service Availability and Reliability of Computer-Based Systems, and Practical System Reliability, also available from Wiley-IEEE Press. RANDEE ADAMS is a consulting member of technical staff in the Software, Solutions and Services Group of Alcatel-Lucent and the coauthor of Beyond Redundancy: How Geographic Redundancy Can Improve Service Availability and Reliability of Computer-Based Systems .
