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Chef Cookbook

By : Marschall

Chef Cookbook

By: Marschall

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.

Preface

Preface

What this book covers

What you need for this book

Who this book is for

Sections

Conventions

Reader feedback

Customer support

Free Chapter

1. Chef Infrastructure

1. 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

How to do it…

How it works…

There's more…

See also

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

2. Evaluating and Troubleshooting Cookbooks and Chef Runs

2. 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

3. Chef Language and Style

3. 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

4. Writing Better Cookbooks

4. 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

5. Working with Files and Packages

5. 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

6. Users and Applications

6. 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

7. Servers and Cloud Infrastructure

7. 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

Index

Customer Reviews

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1 star

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Running the Chef client as a daemon

While you can run the Chef client on your nodes manually whenever you change something in your Chef repository, it's sometimes preferable to have the Chef client run automatically every so often. Letting the Chef client run automatically makes sure that no node misses out any updates.

Getting ready

You need to have a node registered with your Chef server. It needs to be able to run chef-client without any errors.

How to do it…

Let's see how to start the Chef client in daemon mode so that it runs automatically:

Start the Chef client in daemon mode, running every 30 minutes:
```
user@server:~$ sudo chef-client -i 1800
```
Validate that the Chef client runs as a daemon:
```
user@server:~$ ps auxw | grep chef-client
```

How it works…

The -i parameter will start the Chef client as a daemon. The given number is the seconds between each Chef client run. In the previous example, we specified 1,800 seconds, which results in the Chef client running every 30 minutes.

You can use the same command in a service startup script.

Tip

You can use the chef-client cookbook to install the Chef client as a service. See: https://supermarket.chef.io/cookbooks/chef-client for details.

There's more…

Instead of running the Chef client as a daemon, you can use a Cronjob to run it every so often:

user@server:~$ subl /etc/cron.d/chef_client
PATH=/usr/local/bin:/usr/bin:/bin
# m h dom mon dow user command
*/15 * * * * root chef-client -l warn | grep -v 'retrying [1234]/5 in'

This cronjob will run the Chef client every 15 minutes and swallow the first four retrying warning messages. This is important to avoid Cron sending out e-mails if the connection to the Chef server is a little slow and the Chef client needs a few retries.

Note

It is possible to initiate a Chef client run at any time by sending the SIGUSR1 signal to the Chef client daemon:

user@server:~$ sudo killall -USR1 chef-client

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