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

Base image strategy

Maybe separation of duty means that different people have control over different cloud resources or container registries. Maybe some HCL files in a template directory should be read-only while others, such as variable declarations, may be edited. We need to build out a directory structure that accommodates collaboration and also helps us reuse common code. Remember that HCL doesn’t have an include or a require directive to import other files or modules. You can run Packer against a single HCL file or against a directory, which will result in the combination of all HCL files included. It’s not so easy to #include common.hcl from a shared read-only space. Luckily, we have the simple option of symbolic links for this, where you can alias a common template file into your template directory. Here is an example:

$ ln –s ../common/basicconfig.hcl .

If you look at the GitHub repository for this project, you’ll see that the single HCL2 file...