Practical Load BalancingRide the Performance Tiger

Illtil

Peter MembreyDavid Hows

Eelco Plugge

Apress8

Contents

About the Authors xvii

About the Technical Reviewers xviii

Special Thanks to serverlove xix

Acknowledgments xx

Preface xxi

Chapter 1: Introduction 1

The Problem 1

The Solution 2

What Is Load Balancing? 3

Load Balancing, Old Style 3

Load Balancing, New Style 3

Scaling Up 3

Scaling Out 4

Load Balancing, Finally 4

What Makes the Web Tick? 4

Caching: Warp Drive for Your Web Site 5

Load Balancing with DNS 5

Content Delivery Networks 5

Proper Planning Prevents Pretty Poor Performance 6

The Essentials 6

HTTP Load Balancing 6

Load Balancing Your Database 6

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Load Balancing Your Network Connection 7

SSL Load Balancing 7

Clustering for High Availability 7

Load Balancing in the Cloud 7

IPv6: Implementation and Concepts 7

Where To Go Next 8

Summary 8

Chapter 2: How Web Sites Work 9

Let the Games Commence! 10

Coming from a Non-IT Background 10

Kicking Off the Process 10

Finding the Site with DNS 11

Connecting to the Server (Finally!) 11

On the Server itself 12

Talking to the Database 12

Quick Look at Caching 13

Back to the Client 13

Taking a Closer Look 13

The Network 14

TCP 14

DNS 16

Speed, Bandwidth, and Latency 17

Network Summary 20

HTML and the Web 20

HTML 21

Why is Text-Based Important? 21

Why is Linking Important? 22

HTML Summary 23

The Browser, 24

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Web Content 24

Static Content 25

Dynamic Content 25

Creating Dynamic Content 25

Web Content Summary 27

Databases: The Weakest Link 27

Summary 27

Chapter 3: Content Caching: Keeping the Load Light 29

What Is a Cache? 30

Whistle Stop Tour 30

Browser-based Caching 31

Web Accelerators 31

Web Proxies 32

Transparent Web Proxies 33

Edge-based Caching 35

Platform Caching 35

Application Caching 36

Database Caching 37

Just the Beginning 37

Caching Theory: Why Is It so Hard? 37

HTTP 1.0 Caching Support 38

HTTP 1.1 Enhanced Caching Support 38

The Solution 39

Caching Isn't as Easy as It Looks 40

Web Proxies 40

The Squid Proxy Server 41

Getting Started 41

Troubleshooting 43

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Transparent Proxies 43

What's Going On 44

Getting a Helping Hand 45

Squid, the Swiss Army Knife of Proxies 46

Edge-based Caching: Introducing Varnish 46

Sane Caching by Default 47

Installing Varnish 48

Getting Up and Running 49

Customizing Varnish 51

Summary 51

Chapter 4: DNS Load Balancing 53

DNS Details 53

The IP Address 53

The Problem 54

The Solution 54

Taking a Step Back 55

DNS in Depth 55

Querying Yourself 56

Advanced DNS Queries 57

DNS Caching 58

Querying your DNS Cache 59

DNS Cache in Linux 60

The Real Stuff 60

BIND9 61

DNS DB Header 62

DNS Database Entries 63

Loading your DB 65

Checking the Config 65

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Common Issues 66

Testing your DNS 66

DNS Load Balancing 67

Advantages of DNS Load Balancing 67

Issues with DNS Load Balancing 68

Summary 69

Chapter 5: Content Delivery Networks 71

Choosing a CDN Provider 72

Getting Started with Rackspace 72

Adding Content to Your CDN Account 74

The Rackspace Cloud Files API 77

Integrating the API into PHP 77

Authenticating with Your API Key 78

Connecting and Disconnecting 78

Working with Containers 79

Working with Files 85

Other Useful Functions 91

Summary 92

Chapter 6: Planning for Performance and Reliability..... ..............93

yoU MAke Dinner In TiME 94

yoU 94

MAke 97

Dinner 97

In 98

TiME 100

The Importance of Planning 101

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Backups 103

Why Backups Are so Important 103

There May Be Trouble Ahead 103

Automation is a Must 104

Tactical Backups 105

Strategic Backups 105

Incremental vs. Full 106

Please, Please Perform Test Restores! 106

Summary 106

Chapter 7: Load Balancing Basics 109

What Is Load Balancing? 109

What Computing Resources Are Available? 110

Processor (CPU) 110

Memory (RAM) 111

Checking Performance of CPU and RAM with top 111

Network 113

Storage (Disk) 114

Load Balancing in Practice 114

Guiding Principles 115

Understand Your System 115

Planning 116

Monitoring and Testing 116

Summary 116

Chapter 8: Load Balancing Your Web Site 117

Measuring Web Server Performance 117

Accelerating Apache HTTP 120

Disabling Unneeded Modules 120

Disabling DNS Lookups 121

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Using Compression 121

FollowSymLinks and SymLinkslfOwnerMatch 123

Accelerating nginx 123

worker_processes and worker_cpu_affinity 124

Gzip Compression 125

Load Balancing Your Web Server 126

The Setup 127

Preparing the Server 128

Preparing the Workers 130

Testing the Load Balancer 131

Best of Both Worlds 132

Summary 134

Chapter 9: Load Balancing Your Database 135

Setting up the MySQL Cluster 135

Installing the Management Software 137

Configuring the Management Software 138

Preparing the Cluster's Data Nodes 140

Installing the MySQL Server and NOB Daemon 141

Configuring the NDB Daemon 142

Starting the Cluster Node's Services 143

Updating MySQL's Root User 144

Testing the Installation 145

Applying Load Balancing 147

The Setup 148

Setting up the Load Balancer 148

Preparing the Workers 150

Testing the Load Balancer 150

Summary 151

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Chapter 10: Network Load Balancing 153

Sharing the Workload 153

TCP/IP 154

TCP 154

IP 155

Routing 155

The Load Balancer 157

IPVS 160

IPVS Scheduling 160

IPVS Installation onUbuntu 162

IPVS Installation on Centos 163

IPVSADM 164

Expanding IPVS 166

Advanced IPVS 167

Changing Scheduling Algorithm 167

Assigning Weight Values 168

Protocol and Multiple Virtual Servers 170

Another IP Address 171

Making It Stick 173

Summary 174

Chapter 11: SSL Load Balancing 175

What are SSLandTLS? 175

Public-Key Cryptography 176

Trust and Certificate Authorities 177

TLS Encryption 178

TLS Load Balancing 178

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CONTENTS

Configuring SSL on Your Web Server 179

Apache 181

Nginx 182

SSL Acceleration 182

Apache 183

Nginx 183

SSL Termination 183

Configuring Nginx 184

Testing the SSL 185

Further Configurations 187

Engine 187

Caching 188

Protocols 189

Specific Ciphers 189

LVS and Your SSL Terminator 191

Integrated Load Balancer/SSL Terminator 192

Summary 192

Chapter 12: Clustering for High Availability 193

High Availability 194

Single Point of Failure 195

Clustering 197

IPVS Failover 198

Install with Ubuntu 199

Install with Centos 200

Configure 200

Common Config Problems 203

Confirming Your System 204

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Testing 206

Web Server Specifics 207

Ubuntu 207

Centos 207

Advanced Config Options 208

ha.cf 208

Idirectord.cf 208

Web Server 209

Summary 209

Chapter 13: Load Balancing in the Cloud 211

Cloud Computing 211

Virilization 212

Hypervisor 212

Virtualized Resources 215

Managing Virtual Resources 216

Balancing 217

Overprovisioning 219

Planning 219

Cloud Elasticity 220

Working with a Cloud Server 221

Summary 224

Chapter 14: IPv6: Implications and Concepts 225

IPv6 225

Hexadecimal Notation 225

Truncation 226

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IPv4 Exhaustion 226

Approach to IPv6 227

Advantages of IPv6 227

Implementation 228

Internet Connection 229

DNS 230

Operating System 230

Networking 230

Single Gateway Network 231

Dual Network 231

Application Support 231

Apache 231

Nginx 232

Varnish Cache 232

Memcached 233

IPVS 233

Ldirectord 234

Heartbeat 234

Summary 234

Chapter 15: Where to Go Next 235

Recap 236

Monitoring 236

Security 237

Access Control 238

Views 238

Common Exploit Prevention 239

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Operating System Performance 240

Compile Yourself 240

Cut Down 240

High-Performance OS 241

Planning 241

Summary 241

Index.. ....243

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