Book Image

LEARNING PUPPET

By : Jussi Heinonen
Book Image

LEARNING PUPPET

By: Jussi Heinonen

Overview of this book

Puppet is a cross-platform, open source configuration management utility, which runs on various Unix, Linux, and Windows Microsoft platforms. It allows you to automate all your IT configurations, giving you control of what you do to each node, and also when and how you do it. You’ll be able to build and manage development, test, and production environments independently without requiring previous system administration experience. Learning Puppet is a step-by-step guide on how to get started with Puppet development and use Puppet modules as the building blocks to deploy production-ready application cluster in virtual environment. You will begin with the installation of development environment on the VirtualBox hypervisor and Puppet Learning VM that will be used as the platform for testing and development of Puppet modules. Next, you will learn how to manage virtual machines and snapshots effectively and enhance the development experience with advanced VirtualBox features. Later the book will focus on Puppet module development in detail. You will be guided through the process of utilizing existing modules that are available in the public module repository, write your own modules and use them to deploy a real-world web application that includes features such as monitoring and load balancing. You will then learn to scale your environment and turn your static configuration into a dynamic one through stored configurations and PuppetDB. Finally, the book will provide you with practical advice on Puppet troubleshooting and managing your environment with the wealth of features provided by the Puppet Enterprise console.
Table of Contents (12 chapters)
11
Index

Rectifying certificate errors

Every Puppet Agent has its own unique certificate. In Chapter 9, The Puppet Enterprise Console, we learned how to sign a certificate for the web-clone.development.vm node. Certificates are the lifelines for the Puppet agent, which means that, without a working certificate, the Puppet agent can't get any service from the Puppet Master. Certificates do sometimes stop working and this causes problems with deployments. Certificates may stop working, for example, if a node is deleted on the Puppet Master. Let's take a look at certificate errors and how to fix them.

Listing certificates on the Puppet Master

Certificates are stored on the Puppet Master. Certificates can be listed on the command line by running the following command on the Puppet Master node:

# puppet cert list --all

The command outputs a list of certificates that are currently active:

Listing certificates on the Puppet Master

The second certificate from the bottom belongs to the web-clone.development.vm node. Let's delete the certificate...