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

Building containers

Docker, LXC, LXD, and Podman are supported via Packer plugins. At first, it may seem counter-intuitive to use Packer for building containers. Docker does a fairly good job of making container images. The nice part about adding a container builder to your template is that it allows you to package your applications and config in containers at the same time as cloud or VM images. In addition to the builder, the Docker plugin has some very helpful postprocessors to manage the container registry lifecycle:

  • docker import
  • docker push
  • docker save
  • docker tag

You may have Packer build and push containers to your private registry as part of your automation. You may also automate tagging with Packer’s variables or useful HCL date/time functions. Here is an example:

source "docker" "base-docker" {
  image = "ubuntu"
  commit = true
    changes = [