Book Image

HashiCorp Packer in Production

By : John Boero
Book Image

HashiCorp Packer in Production

By: John Boero

Overview of this book

Creating machine images can be time-consuming and error-prone when done manually. HashiCorp Packer enables you to automate this process by defining the configuration in a simple, declarative syntax. This configuration is then used to create machine images for multiple environments and cloud providers. The book begins by showing you how to create your first manifest while helping you understand the available components. You’ll then configure the most common built-in builder options for Packer and use runtime provisioners to reconfigure a source image for desired tasks. You’ll also learn how to control logging for troubleshooting errors in complex builds and explore monitoring options for multiple logs at once. As you advance, you’ll build on your initial manifest for a local application that’ll easily migrate to another builder or cloud. The chapters also help you get to grips with basic container image options in different formats while scaling large builds in production. Finally, you’ll develop a life cycle and retention policy for images, automate packer builds, and protect your production environment from nefarious plugins. By the end of this book, you’ll be equipped to smoothen collaboration and reduce the risk of errors by creating machine images consistently and automatically based on your defined configuration.
Table of Contents (18 chapters)
Part 1: Packer’s Beginnings
Part 2: Managing Large Environments
Part 3: Advanced Customized Packer

Running a script or job across all builders

There are several options to perform tasks in a build environment, ranging from basic scripts to configuration management tools such as Ansible, Puppet, and Chef, among others. There are also troubleshooting provisioners such as breakpoint, where you tell Packer to pause in case you need to inspect something during a build. First, let’s cover the basics of the shell provisioner. Most tasks can generally be done with shell actions. Similar to the file provisioner, there are three main options to specify what you would like to run, as follows:

  • inline: Raw list of strings you would like to run as a script
  • script: Path to a single script you would like to run
  • scripts: List of paths to scripts you would like to run

Take an example where we would like to update an Ubuntu environment and install an app with apt. This can be done inline with two lines. Remember that HCL is tolerant of hanging commas in lists such as...