Knative in Action

by Jacques Chester

Overview

Knative in Action teaches you to build complex and efficient serverless applications.

Summary
Take the pain out of managing serverless applications. Knative, a collection of Kubernetes extensions curated by Google, simplifies building and running serverless systems. Knative in Action guides you through the Knative toolkit, showing you how to launch, modify, and monitor event-based apps built using cloud-hosted functions like AWS Lambda. You’ll learn how to use Knative Serving to develop software that is easily deployed and autoscaled, how to use Knative Eventing to wire together disparate systems into a consistent whole, and how to integrate Knative into your shipping pipeline.

Purchase of the print book includes a free eBook in PDF, Kindle, and ePub formats from Manning Publications.

About the technology
With Knative, managing a serverless application’s full lifecycle is a snap. Knative builds on Kubernetes orchestration features, making it easy to deploy and run serverless apps. It handles low-level chores—such as starting and stopping instances—so you can concentrate on features and behavior.

About the book
Knative in Action teaches you to build complex and efficient serverless applications. You’ll dive into Knative’s unique design principles and grasp cloud native concepts like handling latency-sensitive workloads. You’ll deliver updates with Knative Serving and interlink apps, services, and systems with Knative Eventing. To keep you moving forward, every example includes deployment advice and tips for debugging.

What's inside

Deploy a service with Knative Serving
Connect systems with Knative Eventing
Autoscale responses for different traffic surges
Develop, ship, and operate software

About the reader
For software developers comfortable with CLI tools and an OO language like Java or Go.

About the author
Jacques Chester has worked in Pivotal and VMWare R&D since 2014, contributing to Knative and other projects.

Table of Contents

1 Introduction

2 Introducing Knative Serving

3 Configurations and Revisions

4 Routes

5 Autoscaling

6 Introduction to Eventing

7 Sources and Sinks

8 Filtering and Flowing

9 From Conception to Production

Product Details

ISBN-13:	9781617296642
Publisher:	Manning
Publication date:	03/30/2021
Pages:	272
Product dimensions:	7.38(w) x 9.25(h) x 0.60(d)

About the Author

Jacques Chester is an engineer at VMware, via the Pivotal acquisition. He has worked in R&D since 2015, contributing to several projects, including Knative. Before R&D, Jacques worked for Pivotal Labs as a consulting software engineer.

Table of Contents

Foreword xiii

Preface xiv

Acknowledgements xv

About this book xvii

About the author xx

About the cover illustration xxi

1 Introduction 1

1.1 What is Knative? 2

Deploying, upgrading, and routing 3

Autoscaling 3

Eventing 3

1.2 So what? 3

1.3 Where Knative shines 4

Workloads with unpredictable, latency-insensitive demand 4

Stitching together events from multiple sources 6

Decomposing monoliths in small increments 7

1.4 It's a hit 7

Trouble in paradise 11

1.5 Changing things 12

1.6 What's in the Knative box? 14

Serving 14

Eventing 15

Serving and Eventing 15

1.7 Keeping things under control 16

Loops 17

Loops within loops 19

1.8 Are you ready? 22

2 Introducing Knative Serving 24

2.1 A walkthrough 25

Your first deployment 25

KOWR second deployment 26

Conditions 27

What does Active mean? 28

Changing the image 29

Splitting traffic 30

2.2 Serving components 32

The controller and reconcilers 32

The Webhook 33

Networking controllers 34

Autoscaler, Activator, and Queue-Proxy 35

3 Configurations and Revisions 39

3.1 Those who cannot remember the past are condemned to redeploy it 40

3.2 The bedtime story version of the history of deployment as a concept 41

The Blue/Green deployment 42

The Canary deployment 45

Progressive deployment 45

Back to the future 47

3.3 The anatomy of Configurations 48

Configuration status 51

Taking it all in with kubectl describe 52

3.4 The anatomy of Revisions 54

Revision basics 55

Container basics 57

Container images 58

The command 61

The environment, directly 63

The environment, indirectly 65

Configuration via files 69

Probes 71

Setting consumption limits 73

Container concurrency 75

Timeout seconds 77

4 Routes 80

4.1 Using kn to work with Routes 81

4.2 The anatomy of Routes 82

4.3 The anatomy of TrafficTargets 84

ConfigurationName and revisionName 85

LatestRevision 87

Tag 88

5 Autoscaling 100

5.1 The autoscaling problem 101

5.2 Autoscaling when there are zero instances 103

The Autoscaler panics 106

5.3 Autoscaling when there are one or a few instances 106

5.4 Autoscaling when there are many instances 108

5.5 A little theory 109

Control 109

Queueing 109

5.6 The actual calculation 112

To panic, or not to panic, that is the question 118

5.7 Configuring autoscaling 120

How settings get applied 121

Setting scaling limits 123

Setting scaling rates 124

Setting target values 125

Setting decision intervals 127

Setting window size 127

Setting the panic threshold 128

Setting the target burst-capacity 128

Other autoscalers 129

5.8 A cautionary note 129

6 Introduction to Eventing 132

6.1 The road to CloudEvents 133

6.2 The anatomy of CloudEvents 136

Required attributes 137

Optional attributes 138

Extension attributes 140

6.3 A word about event formats and protocol bindings 142

Structured content mode 142

Binary content mode 143

Batched content mode 144

6.4 A walkthrough 144

6.5 The basic architecture of Eventing 153

Messaging 153

Eventing 154

Sources 154

Flows 155

Duck types 155

Sources and Sinks 159

7.1 Sources 159

The anatomy of Sources 160

Using kn to work with Sources 161

7.2 The Sink 165

7.3 The mysterious SinkBinding (and its sidekick, ContainerSource) 167

Provisioning and binding are not the same 168

7.4 Other Sources 169

8 Filtering and Flouring 171

8.1 The Broker 172

8.2 Filters 173

Filtering on custom attributes 176

Nice things that Eventing adds for you 181

8.3 Sequences 183

A walkthrough 183

8.4 The anatomy of Sequences 188

Step 188

Reply 188

ChannelTemplate and Channels 189

Mixing Sequences and filters 191

8.5 Parallels 192

A walkthrough 193

8.6 Dealing with failures 200

Retries and backoffs 201

Dead letters 202

The bad news 203

9 From Conception to Production 204

9.1 Turning your software into something runnable 205

Always use digests 205

Using Cloud Native Buildpacks (CNBs) and the pack tool 208

9.2 Getting your software to somewhere it runs 212

9.3 Knowing how your software is running 222

Logs 224

Metrics 225

Traces 231

Appendix Installing Knative for Development 235

Index 241