Take your Node.js application into production-ready status, capable of scaling up to whatever your needs might be. You'll discover that architecting for successful, popular sites is an essential tool of any professional Node.js developer, and learning to scale your own applications is a great place to start. Using this book you will learn when to scale, what factors should trigger scaling, and what architectural techniques are best suited for scaling. You will also explore common pitfalls that arise when scaling a Node.js application and solutions to correct them. Including analyses of success cases at the largest-scale companies, such as Netflix and Paypal, this book will get you started with scaling in no time at all. What You'll Learn • Determine what factors should trigger the need to scale • Discover different architectural patterns that lend themselves to scaling • Resolve problems that arise when scaling up a Node.js application • Monitor a platform in order to understand when to start scaling Who This Book Is For The main audience for this book are Node.js developers with a mid-level understanding of the technology. Novice Node users will also benefit from the coverage of generic scaling-related topics. Table of Contents 5 About the Author 8 About the Technical Reviewer 9 Acknowledgments 10 Introduction 11 Chapter 1: The Need to Scale 12 External Factors 12 Traffic Increase 12 Direct Effects 13 Indirect Effects 14 Increased Processing Power Required 15 Your Service Is Degraded 15 Your Service Is Dead 16 Internal Factors 17 High Availability 18 Fault Tolerance 22 Redundancy 23 Triple Modular Redundancy 24 Forward Error Correction 25 Checkpointing 26 Dealing with Distributed Checkpointing 26 When to Use? 27 Byzantine Fault-Tolerance 27 Summary 29 Chapter 2: Architectural Patterns 30 The Patterns 30 Layered Architecture 31 MVC Is Not Layered 33 Client-Server 36 Master-Slave 38 Event-Bus or Event-Driven Architectures 40 Microservices Architecture 43 The Broker Pattern 45 Lambda Architectures 48 Summary 51 Chapter 3: Ways to Scale 52 Scaling Techniques 52 Vertical or Horizontal Scaling? 52 Taking Advantage of the Cloud 55 The Power of a Multi-Zone Deployment 57 Clustering Your Application 58 Clustering with PM2 66 In Conclusion 68 Microservices to the Rescue 68 In Conclusion 71 Summary 72 Chapter 4: Challenges when Scaling 73 Dealing with Your Log Files 73 You’re Just Logging into stdout and stderr 75 You’re Logging into a Single File 79 Throw Away Your Logger and Use a Real One 81 Sharing Memory between Processes 83 Single Points of Failure? No Thank You! 86 Knowing When to Stop 88 System-Level Indicators (SLIs) 89 System Level Objectives (SLOs) 90 What Happens When We Don’t Meet Our SLOs? 91 Agreeing on Your SLAs 92 Stateful Apps and Multi-Server Scenarios 92 Summary 96 Chapter 5: When to Scale? 97 Monitoring 97 Alerting 99 Monitoring Your Apps 101 Adding AWS Metrics into Your Dashboard 113 Reacting to Your Metrics 114 Step 1: Creating Your Alerts 115 Steps 2 through 4: Setting Everything Else 118 Summary 119 Chapter 6: Testing Your Application 120 Testing 101 120 The Definition 121 The Tools 124 Test Cases and Test Suites 124 Assertions 124 Stubs, Mocks, Spies and Dummies 125 Stubs 127 Mocks 129 Spies 131 Dummies 132 Fixtures 132 Best Practices 132 Testing with Node.js 134 Testing without External Modules 134 Mocha 137 Installing and First Steps 138 Testing Asynchronous Code 139 Testing: a Practical Example 141 Integration Testing 146 Testing Approaches 147 The Big Bang Approach 147 The Gradual Approach 149 Summary 150 Chapter 7: Success Cases 151 PayPal 151 Uber 154 LinkedIn 156 Biggest Challenges 158 Monitoring 158 Profiling 158 Netflix 159 Summary 163 Index 165 Front Matter ....Pages i-xv The Need to Scale (Fernando Doglio)....Pages 1-18 Architectural Patterns (Fernando Doglio)....Pages 19-40 Ways to Scale (Fernando Doglio)....Pages 41-61 Challenges when Scaling (Fernando Doglio)....Pages 63-86 When to Scale? (Fernando Doglio)....Pages 87-109 Testing Your Application (Fernando Doglio)....Pages 111-141 Success Cases (Fernando Doglio)....Pages 143-156 Back Matter ....Pages 157-162
