Learning Puppet 4 a guide to configuration management and automation

587 Pages·2016·8.703 MB·English

by  Rhett, Jo

Learning
Puppet 4
A GUIDE TO CONFIGURATION MANAGEMENT AND AUTOMATION
Jo Rhett

Learning Puppet 4
A Guide to Configuration Management
and Automation
Jo Rhett
BBeeiijjiinngg BBoossttoonn FFaarrnnhhaamm SSeebbaassttooppooll TTookkyyoo
Learning Puppet 4
by Jo Rhett
Copyright © 2016 Jo Rhett. All rights reserved.
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April 2016: First Edition
Revision History for the First Edition
2016-03-22: First Release
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978-1-491-90766-5
[LSI]
Table of Contents
Foreword. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxi
Preface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxiii
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxxi
Part I. Controlling with Puppet Apply
1. Thinking Declarative. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Handling Change 3
Using Idempotence 4
Declaring Final State 5
Reviewing Declarative Programming 6
2. Creating a Learning Environment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Installing Vagrant 8
Installing Vagrant on Mac 8
Installing Git Tools on Windows 10
Installing VirtualBox on Windows 11
Installing Vagrant on Windows 14
Starting a Bash Shell 17
Downloading a Box 18
Cloning the Learning Repository 19
Install the Vagrant vbguest Plugin 19
Initializing the Vagrant Setup 19
Verifying the /vagrant Filesystem 21
Initializing Non-Vagrant Systems 22
iii
Installing Some Helpful Utilities 22
Choosing a Text Editor 22
On the Virtual System 23
On Your Desktop 24
In Your Profile 24
Reviewing the Learning Environment 25
3. Installing Puppet. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Adding the Package Repository 27
What Is a Puppet Collection? 28
Installing the Puppet Agent 28
Reviewing Dependencies 29
Reviewing Puppet 4 Changes 30
Linux and Unix 30
Windows 32
Making Tests Convenient 32
Running Puppet Without sudo 33
Running Puppet with sudo 34
Reviewing Puppet Installation 35
4. Writing Manifests. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Implementing Resources 37
Applying a Manifest 38
Declaring Resources 39
Viewing Resources 40
Executing Programs 41
Was That Idempotent? 42
Managing Files 43
Finding File Backups 44
Restoring Files 45
Avoiding Imperative Manifests 45
Testing Yourself 47
Reviewing Writing Manifests 47
5. Using the Puppet Configuration Language. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Defining Variables 50
Defining Numbers 51
Creating Arrays and Hashes 52
Mapping Hash Keys and Values 52
Using Variables in Strings 53
Using Braces to Limit Problems 53
Preventing Interpolation 54
iv | Table of Contents
Using Unicode Characters 55
Avoiding Redefinition 55
Avoiding Reserved Words 56
Learning More 57
Finding Facts 57
Calling Functions in Manifests 59
Using Variables in Resources 60
Defining Attributes with a Hash 62
Declaring Multiple Resource Titles 63
Declaring Multiple Resource Bodies 63
Modifying with Operators 64
Adding to Arrays and Hashes 65
Removing from Arrays and Hashes 65
Order of Operations 66
Using Comparison Operators 66
Evaluating Conditional Expressions 68
Matching Regular Expressions 70
Building Lambda Blocks 71
Looping Through Iterations 72
each() 73
filter() 75
map() 76
reduce() 76
slice() 78
with() 79
Capturing Extra Parameters 79
Iteration Wrap-Up 80
Reviewing Puppet Configuration Language 80
6. Controlling Resource Processing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Adding Aliases 81
Specifying an Alias by Title 82
Adding an Alias Metaparameter 82
Preventing Action 82
Auditing Changes 83
Defining Log Level 84
Filtering with Tags 84
Skipping Tags 85
Limiting to a Schedule 86
Utilizing periodmatch 87
Avoiding Dependency Failures 90
Declaring Resource Defaults 91
Table of Contents | v
Reviewing Resource Processing 91
7. Expressing Relationships. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Managing Dependencies 93
Referring to Resources 94
Ordering Resources 95
Assuming Implicit Dependencies 95
Triggering Refresh Events 96
Chaining Resources with Arrows 97
Processing with Collectors 98
Understanding Puppet Ordering 99
Debugging Dependency Cycles 100
Avoiding the Root User Trap 101
Utilizing Stages 103
Reviewing Resource Relationships 103
8. Upgrading Puppet 3 Manifests. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
Replacing Deprecated Features 105
Junking the Ruby DSL 105
Upgrading Config Environments 106
Removing Node Inheritence 107
Disabling puppet kick 107
Qualifying Relative Class Names 107
Losing the Search Function 108
Replacing Import 108
Documenting Modules with Puppet Strings 108
Installing the Tagmail Report Processor 109
Querying PuppetDB 109
Preparing for the Upgrade 109
Validating Variable Names 109
Quoting Strings 110
Preventing Numeric Assignment 110
Testing Boolean Facts 112
Qualifying Defined Types 112
Adding Declarative Permissions 113
Removing Cron Purge 114
Replacing MSI Package Provider 114
Adjusting Networking Facts 114
Testing with the Future Parser 115
Using Directory Environments 115
Duplicating a Master or Node 116
Enhancing Older Manifests 116
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Adding else to unless 116
Calling Functions in Strings 116
Matching String Regexps 117
Letting Expressions Stand Alone 117
Chaining Assignments 118
Chaining Expressions with a Semicolon 118
Using Hash and Array Literals 118
Configuring Error Reporting 119
9. Wrap-Up of Puppet Basics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
Best Practices for Writing Manifests 122
Learning More About Puppet Manifests 122
Part II. Creating Puppet Modules
10. Creating a Test Environment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
Verifying the Production Environment 125
Creating the Test Environment 125
Changing the Base Module Path 126
Skipping Ahead 126
11. Separating Data from Code. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
Introducing Hiera 127
Creating Hiera Backends 128
Hiera Data in YAML 128
Hiera Data in JSON 129
Puppet Variable and Function Lookup 130
Configuring Hiera 130
Backends 131
Backend Configuration 131
Logger 131
Hierarchy 132
Merge Strategy 133
Complete Example 134
Looking Up Hiera Data 134
Checking Hiera Values from the Command Line 135
Performing Hiera Lookups in a Manifest 136
Testing Merge Strategy 136
Providing Global Data 139
Table of Contents | vii
12. Using Modules. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
Finding Modules 141
Puppet Forge 141
Public GitHub Repositories 142
Internal Repositories 143
Evaluating Module Quality 143
Puppet Supported 144
Puppet Approved 144
Quality Score 145
Community Rating 148
Installing Modules 149
Installing from a Puppet Forge 149
Installing from GitHub 150
Testing a Single Module 151
Defining Config with Hiera 152
Assigning Modules to Nodes 153
Using Hiera for Module Assignment 153
Assigning Classes to Every Node 154
Altering the Class List per Node 155
Avoiding Node Assignments in Manifests 155
Upgrading from Puppet 2 or 3 157
Examining a Module 158
Reviewing Modules 159
13. Designing a Custom Module. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161
Choosing a Module Name 161
Avoiding Reserved Names 162
Generating a Module Skeleton 162
Modifying the Default Skeleton 163
Understanding Module Structure 164
Installing the Module 164
Creating a Class Manifest 164
What Is a Class? 165
Declaring Class Resources 165
Accepting Input 166
Sharing Files 168
Testing File Synchronization 169
Synchronizing Directories 170
Parsing Templates 171
Common Syntax 171
Using Puppet EPP Templates 172
Using Ruby ERB Templates 175
viii | Table of Contents