10 Things I do when debugging terraform errors

Terraform is an great tool for managing infrastructure as code, but debugging Terraform configurations and deployments is not so easy, and it is an essential skill for every DevOps engineer.

1. Understand Terraform's Execution Plan

Before applying any changes, run terraform plan. This command shows you what Terraform will do before it does it. It's your first line of defense in catching potential issues.

2. Check for Syntax Errors

Run terraform validate to ensure your configuration files are free of syntax errors. This is a quick win to avoid many common issues. There are many terraform lint tools online, find the best one for you.

3. Use Logging and Debugging Tools

Terraform provides verbose output using the -debug flag. It can help you identify problems and understand how Terraform makes decisions.

4. Isolate the Problematic Resource

If you're encountering issues, isolate the problematic resource. Comment out parts of your configuration to identify the source of the problem.

5. Leverage Remote State

Using remote state management (e.g., Terraform Cloud or AWS S3) allows you to collaborate and share state. It can also help pinpoint issues by comparing local and remote state.

6. Check Dependencies and Execution Order

Ensure that resources are declared in the correct order, considering dependencies.

7. Use "output"

Write output resources and understand what the actual value of a resource that errors out. This is like console output for you, but in terraform way.

8. Inspect Resource Attributes

Use terraform show to examine the attributes of Terraform-managed resources. This is particularly useful when debugging after an apply operation.

9. Compare terraform with the real resource

When you have no clue at all, you can create resource via cloud provider's GUI, then import the resource into your terraform configuration file, run terraform plan, this way, it tell you the difference and (hopefully) helps you find the solution.

10. Community and Documentation

Terraform has a vibrant community and extensive documentation. Don't hesitate to seek help from forums or consult the official documentation for guidance on common issues.

Debugging Terraform may seem like a "not-too-fun" task, but armed with these tips, you'll be well-equipped to tackle challenges head-on. Remember, debugging is not a sign of failure; it's a part of the learning process. Terraform empowers you to manage infrastructure efficiently, and mastering the art of debugging is a crucial step on your DevOps journey.