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

Controlling flow and using breakpoints

We may also need Packer to pause before continuing part of a build. Remember—by default, an error will cause Packer to destroy the environment, which unfortunately makes it hard for troubleshooting what went wrong. Rather than debugging through a build step by step, we can do some basic options to have Packer stop where we want it to.

First and foremost is the -on-error option. This can have one of four values. By default, it is set to cleanup, which explains why Packer deletes the build environment after errors. Again, as per the Packer documents, it may be helpful to set it to one of the following instead:

  • abort: Exits without cleanup.
  • ask: Prompts and waits for you to decide to clean up, abort, or retry the failed step.
  • cleanup (default): Exits with cleanup. This is the default.
  • run-cleanup-provisioner: Aborts with the error-cleanup-provisioner if one is defined.

If running Packer interactively, the ask...