Chef Cookbook - Third Edition

Chef Cookbook - Third Edition

By : Matthias Marschall

Buy this Book

Chef Cookbook - Third Edition

By: Matthias Marschall

Buy this Book

Overview of this book

Chef is a configuration management tool that lets you automate your more cumbersome IT infrastructure processes and control a large network of computers (and virtual machines) from one master server. This book will help you solve everyday problems with your IT infrastructure with Chef. It will start with recipes that show you how to effectively manage your infrastructure and solve problems with users, applications, and automation. You will then come across a new testing framework, InSpec, to test any node in your infrastructure. Further on, you will learn to customize plugins and write cross-platform cookbooks depending on the platform. You will also install packages from a third-party repository and learn how to manage users and applications. Toward the end, you will build high-availability services and explore what Habitat is and how you can implement it.

Chef Cookbook - Third Edition

Credits

About the Author

About the Reviewer

www.PacktPub.com

Customer Feedback

Preface

Free Chapter

Chef Infrastructure

Introduction

Using version control

Installing the Chef Development Kit on your workstation

Using the hosted Chef platform

Managing virtual machines with Vagrant

Creating and using cookbooks

Inspecting files on your Chef server with knife

Defining cookbook dependencies

Managing cookbook dependencies with Berkshelf

Using custom knife plugins

Deleting a node from the Chef server

Developing recipes with local mode

Using roles

Using environments

Freezing cookbooks

Running the Chef client as a daemon

Evaluating and Troubleshooting Cookbooks and Chef Runs

Introduction

Testing your Chef cookbooks with cookstyle and Rubocop

Flagging problems in your Chef cookbooks with Foodcritic

Test-driven development for cookbooks using ChefSpec

Compliance testing with InSpec

Integration-testing your Chef cookbooks with Test Kitchen

Showing affected nodes before uploading cookbooks

Overriding a node's run list to execute a single recipe

Using chef-shell

Using why-run mode to find out what a recipe might do

Debugging Chef client runs

Inspecting the results of your last Chef run

Using Reporting to keep track of all your Chef client runs

Raising and logging exceptions in recipes

Diff-ing cookbooks with knife

Using community exception and report handlers

Chef Language and Style

Introduction

Using community Chef style

Using attributes to dynamically configure recipes

Using templates

Mixing plain Ruby with Chef DSL

Installing Ruby gems and using them in recipes

Using libraries

Creating your own custom resource

Extending community cookbooks by using application wrapper cookbooks

Creating custom Ohai plugins

Creating custom knife plugins

Writing Better Cookbooks

Introduction

Setting environment variables

Passing arguments to shell commands

Overriding attributes

Using search to find nodes

Using data bags

Using search to find data bag items

Using encrypted data bag items

Accessing data bag values from external scripts

Getting information about the environment

Writing cross-platform cookbooks

Making recipes idempotent by using conditional execution

Working with Files and Packages

Introduction

Creating configuration files using templates

Using pure Ruby in templates for conditionals and iterations

Installing packages from a third-party repository

Installing software from source

Running a command when a file is updated

Distributing directory trees

Cleaning up old files

Distributing different files based on the target platform

Users and Applications

Introduction

Creating users from data bags

Securing the Secure Shell daemon

Enabling passwordless sudo

Managing NTP

Installing nginx from source

Creating nginx virtual hosts

Creating MySQL databases and users

Managing Ruby on Rails applications

Managing Varnish

Managing your local workstation with Chef Pantry

Servers and Cloud Infrastructure

Introduction

Creating cookbooks from a running system with Blueprint

Running the same command on many machines at once

Setting up SNMP for external monitoring services

Deploying a Nagios monitoring server

Using HAProxy to load-balance multiple web servers

Using custom bootstrap scripts

Managing firewalls with iptables

Managing fail2ban to ban malicious IP addresses

Managing Amazon EC2 instances

Managing applications with Habitat

Index

Customer Reviews

5 star

4 star

3 star

2 star

1 star

Using roles

Roles group nodes with similar configurations. Typical cases are using roles for web servers, database servers, and so on.

You can set custom run lists for all the nodes in your roles and override attribute values from within your roles.

Let's see how to create a simple role.

Getting ready

For the following examples, I assume that you have a node named server and that you have at least one cookbook (I'll use the ntp cookbook) registered with your Chef server.

How to do it…

Let's create a role and see what we can do with it:

Create a role:

mma@laptop:~/chef-repo $ subl roles/web_servers.rb
name "web_servers"
description "This role contains nodes, which act as web servers"
run_list "recipe[ntp]"
default_attributes 'ntp' => {
  'ntpdate' => {
    'disable' => true
  }
}

Upload the role on the Chef server:

mma@laptop:~/chef-repo $ knife role from file web_servers.rb
Updated Role web_servers

Assign the role to a node called server:

mma@laptop:~/chef-repo $ knife node run_list add server 'role[web_servers]'
server:
  run_list: role[web_servers]

user@server:~$ sudo chef-client
...TRUNCATED OUTPUT...
[2016-10-03T18:52:10+00:00] INFO: Run List is [role[web_servers]]
[2016-10-03T18:52:10+00:00] INFO: Run List expands to [ntp]
[2016-10-03T18:52:10+00:00] INFO: Starting Chef Run for server
...TRUNCATED OUTPUT...

How it works...

You define a role in a Ruby (or a JSON) file inside the roles folder of your Chef repository. A role consists of a name attribute and a description attribute. Additionally, a role usually contains a role-specific run list and role-specific attribute settings.

Every node with a role in its run list will have the role's run list expanded into its own. This means that all the recipes (and roles) that are in the role's run list will be executed on your nodes.

You need to upload your role to your Chef server by using the knife role from file command.

Only then should you add the role to your node's run list.

Running the Chef client on a node having your role in its run list will execute all the recipes listed in the role.

The attributes you define in your role will be merged with attributes from environments and cookbooks, according to the precedence rules described at https://docs.chef.io/roles.html#attribute-precedence.

Chef Cookbook - Third Edition

By : Matthias Marschall

Chef Cookbook - Third Edition

By: Matthias Marschall

Overview of this book

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