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)
1
Part 1: Packer’s Beginnings
7
Part 2: Managing Large Environments
11
Part 3: Advanced Customized Packer

Using environment variables for logging and debugging

Sometimes, we need more verbose information about a build to drill down or debug more details about a build environment or failure. Packer has a few very helpful options for this. It’s a bit confusing that Packer debug and log modes are separate functions. With the PACKER_LOG environment variable set to anything, Packer will dump trace output to stderr:

export PACKER_LOG=1

You may also direct it to a file instead of stderr using the PACKER_LOG_FILE environment variable. The PACKER_LOG option gives verbose information about Packer’s internal operation and is compatible with the -machine-readable flag.

Packer’s -debug flag shows similar output, but Packer will pause at each step of the build waiting for someone to hit Enter to continue. The -debug flag is helpful for manual and interactive builds but not for automated builds where nobody is present to hit a Return key. Unfortunately, the -debug and -machine...