Since CFEngine was first created by Mark Burgess in 1993, configuration management tools have been constantly evolving. Followed by the emergence of more modern tools such as Puppet and Chef, there are now a large number of choices available to a system administrator.
Ansible is one of the newer tools to arrive into the configuration management space. Where other tools have focused on completeness and configurability, Ansible has bucked the trend and, instead, focused on simplicity and ease of use.
In this book, we aim to show you how to use Ansible from the humble beginnings of its CLI tool, to writing playbooks, and then managing large and complex environments. Finally, we teach you how to extend Ansible by writing your own modules.
Chapter 1, Getting Started with Ansible, teaches you the basics of Ansible, how to build an inventory, how to use modules, and, most importantly, how to get help.
Chapter 2, Simple Playbooks, teaches you how to combine multiple modules to create Ansible playbooks to manage your hosts.
Chapter 3, Advanced Playbooks, delves deeper into Ansible's scripting language and teaches you more complex language constructs.
Chapter 4, Larger Projects, teaches you the techniques to scale Ansible configurations to large deployments containing many complicated systems.
Chapter 5, Custom Modules, teaches you how to expand Ansible beyond its current capabilities.
To use this book, you will need at least the following:
A text editor
A machine with Linux operating system
Python 2.6.x
However, to use Ansible to its full effect, you should have several Linux machines available to be managed. You could use a virtualization platform to simulate many hosts, if required.
This book is intended for those who want to understand the basics of how Ansible works. It is expected that you have rudimentary knowledge of how to set up and configure Linux machines. In parts of the book, we cover the configuration files of BIND, MySQL, and other Linux daemons; a working knowledge of these would be helpful, but is certainly not required.
In this book, you will find a number of styles of text that distinguish between different kinds of information. Here are some examples of these styles, and an explanation of their meaning.
Code words in text are shown as follows: "We can include other contexts through the use of the include directive."
A block of code is set as follows:
[group] machine1 machine2 machine3
When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:
tasks:
- name: install apache
action: yum name=httpd state=installed
- name: configure apache
copy: src=files/httpd.conf dest=/etc/httpd/conf/httpd.confAny command-line input or output is written as follows:
ansible machinename -u root -k -m ping
New terms and important words are shown in bold.
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