ARCHITECTING
THE CLOUD
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The U.S. Technology Skills Gap: What Every Technology Executive Must Know to Save America ’s Future by Gary J. Beach
Architecting the Cloud: Design Decisions for Cloud Computing Service Models (SaaS, PaaS, and IaaS) by Michael Kavis
DESIGN DECISIONS FOR CLOUD COMPUTING
SERVICE MODELS (SaaS, PaaS, AND IaaS)
Michael Kavis
ARCHITECTING
THE CLOUD
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Copyright © 2014 by Michael Kavis. All rights reserved. Published by John Wiley & Sons, Inc., Hoboken, New Jersey. Published simultaneously in Canada.
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ISBN 978-1-118-61761-8 (cloth) ISBN 978-1-118-82627-0 (epdf ) ISBN 978-1-118-82646-1 (epub) ISBN 978-1-118-69177-9 (o-book) Printed in the United States of America 10 9 8 7 6 5 4 3 2 1
I dedicate this book to my parents, John and Deme, and my brother, Bill, whose work ethic and drive to be the best in their fi elds serve as inspiration for me to excel and fully
ix FOREWORD xiii
PREFACE xv
ACKNOWLEDGMENTS xix ABOUT THE AUTHOR xxi
C H A P T E R 1 Why Cloud, Why Now? 1
Evolution of Cloud Computing 3 Enter the Cloud 6
Start-Up Case Study: Instagram, from Zero to a Billion Overnight 8 Established Company Case Study: Netfl ix, Shifting from On-Premises to the Cloud 9
Government Case Study: NOAA, E-mail, and Collaboration in the Cloud 10
Not-for-Profi t Case Study: Obama Campaign, Six-Month Shelf-Life with One Big Peak 10
Summary 11
C H A P T E R 2 Cloud Service Models 13
Infrastructure as a Service 13 Platform as a Service 15 Software as a Service 17 Deployment Models 18 Summary 22
C H A P T E R 3 Cloud Computing Worst Practices 23
Avoiding Failure When Moving to the Cloud 23 Migrating Applications to the Cloud 23 Misguided Expectations 27
Misinformed about Cloud Security 29
Selecting a Favorite Vendor, Not an Appropriate Vendor 31 Outages and Out-of-Business Scenarios 31
Underestimating the Impacts of Organizational Change 33 Skills Shortage 35
x CONTENTS
Misunderstanding Customer Requirements 36 Unexpected Costs 37
Summary 39
C H A P T E R 4 It Starts with Architecture 41
The Importance of Why, Who, What, Where, When, and How 41
Start with the Business Architecture 43 Identify the Problem Statement (Why) 47 Evaluate User Characteristics (Who) 48
Identify Business and Technical Requirements (What) 48 Visualize the Service Consumer Experience (Where) 49 Identify the Project Constraints (When and with What) 51 Understand Current State Constraints (How) 52
Summary 54
C H A P T E R 5 Choosing the Right Cloud Service Model 55
Considerations when Choosing a Cloud Service Model 56 When to Use SaaS 59
When to Use PaaS 62 When to Use IaaS 65
Common Cloud Use Cases 68 Summary 69
C H A P T E R 6 The Key to the Cloud: RESTful Services 71
Why REST? 72
The Challenges of Migrating Legacy Systems to the Cloud 74
Summary 75
C H A P T E R 7 Auditing in the Cloud 77
Data and Cloud Security 78 Auditing Cloud Applications 78 Regulations in the Cloud 80 Audit Design Strategies 83 Summary 85
CONTENTS xi C H A P T E R 8 Data Considerations in the Cloud 87
Data Characteristics 87
Multitenant or Single Tenant 92 Choosing Data Store Types 95 Summary 98
C H A P T E R 9 Security Design in the Cloud 99
The Truth about Data in the Cloud 100 How Much Security Is Required 101
Responsibilities for Each Cloud Service Model 104 Security Strategies 108
Areas of Focus 110 Summary 118
C H A P T E R 10 Creating a Centralized Logging Strategy 119
Log File Uses 119
Logging Requirements 120 Summary 124
C H A P T E R 11 SLA Management 127
Factors That Impact SLAs 127 Defi ning SLAs 130
Managing Vendor SLAs 132 Summary 135
C H A P T E R 12 Monitoring Strategies 137
Proactive vs. Reactive Monitoring 137 What Needs to Be Monitored? 138 Monitoring Strategies by Category 139 Monitoring by Cloud Service Level 145 Summary 147
C H A P T E R 13 Disaster Recovery Planning 149
What Is the Cost of Downtime? 149 Disaster Recovery Strategies for IaaS 151
Recovering from a Disaster in the Primary Data Center 152 Disaster Recovery Strategies for PaaS 157
xii CONTENTS
Disaster Recovery Strategies for SaaS 159 Disaster Recovery Hybrid Clouds 160 Summary 162
C H A P T E R 14 Leveraging a DevOps Culture to Deliver Software Faster and More Reliably 163
Developing the DevOps Mind-Set 163 Automate Infrastructure 165
Automate Deployments 166 Design Feature Flags 167
Measure, Monitor, and Experiment 167
Continuous Integration and Continuous Delivery 168 Summary 170
C H A P T E R 15 Assessing the Organizational Impact of the Cloud Model 171
Enterprise Model vs. Elastic Cloud Model 172 IT Impact 173
Business Impacts 174
Organization Change Planning 178 Change in the Real World 180 Summary 181
C H A P T E R 16 Final Thoughts 183
The Cloud Is Evolving Rapidly 183 Cloud Culture 185
New Business Models 186 PaaS Is the Game Changer 187 Summary 190
xiii
FOREWORD
I fi rst met Mike Kavis when he brought our Licensed ZapThink Architect SOA course to his company in Florida several years ago. As the vice president of architecture for this fi rm, Mike hoped to wrangle his group of developers to help them think like architects. And while I couldn ’t transform developers into architects in four days, the thrust of the course was to help people think like architects .
The book you have in your hands now has the same mission. Cloud com-puting as an approach to IT infrastructure is still emerging, and thus the tech-nical details are still in fl ux—but the architectural principles of the cloud are now falling into place. But only by thinking like an architect will you be able to take advantage of the full power of the cloud.
Architects are in a unique position in the IT shop, because they have one foot in the business and the other squarely ensconced in the technology. They must understand the nuts and bolts of what works and what doesn ’t without falling victim to the techie tunnel vision that infl icts so many IT people. But they must also live and breathe the business: its strategy, its goals, and most importantly, its problems.
Architecting the Cloud connects these dots. Mike Kavis has intentionally avoided product- or vendor-specifi c details, focusing instead on the challenges that architects, as well as stakeholders in the architecture, should address—in other words, connecting the business problem with the appropriate solution. A truism to be sure, but easier said than done in the cloud.
The reason that solving business challenges in the cloud is so diffi cult is because the cloud is not just one thing. It is many diverse things: SaaS, PaaS, and IaaS service models, public, private, and hybrid deployment models, not to mention diverse value propositions. Some organizations seek to save money with the cloud while others want to shift capital to operational expense. On top of these benefi ts is elasticity: dealing better with unpredictable demand for IT resources.
Never before has architecture mattered so much. Building working solu-tions in the cloud that actually address the business need depends upon it. With his hands-on experience architecting such cloud solutions, Mike Kavis has the experience and insight to lead the way.
—Jason Bloomberg President, ZapThink
