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

Injecting your config or artifacts

Provisioners can take various forms but are limited to the abilities of the communicator. Usually, you will want to upload something to each environment. Sometimes you may want certain provisioners to be included or excluded for certain images. For example, a PowerShell script that you want to run on Windows VMs may not apply to Linux VMs or other environments. There are optional qualifiers for provisioners that can help you with complex workflows. For example, build sources may be included or excluded for each provisioner. By default, a provisioner is applied to every build source. For example, here we use the only qualifier to apply a provisioner to one or more sources we specify:

provisioner "shell" {
  only = ["qemu.base", "otherbuilder.othersource"]

It’s also possible to override and customize the provisioner for certain sources, as in the following example. These special cases should be used...