One of the essentials to ensure stable environments is to test IaC changes. Following are some strategies for effective testing:
Static Code Analysis: Use tools such as TFLint or Checkov to validate your Terraform or CloudFormation templates for errors, security concerns, best practice violations, etc. These can be integrated into CI pipelines to catch errors much earlier.
Unit Testing: You can use the plan command of Terraform or Terratest to test your configurations and mock resources. For example, you could write tests in Go using Terratest to cover the logic of your infrastructure before deploying it.
Policy as Code: You can enforce standards using policies through tools like OPA (Open Policy Agent) or HashiCorp Sentinel. This also includes the restriction of certain regions or instance types.
Integration Testing in Staging: Deploy your IaC in a staging environment. This helps you test the kind of interactions between these components in real life. For example, you can create a separate workspace or environment only for Terraform. It enables validation of functionality before applying changes in production.
Automate CI/CD Pipeline: These testing steps should be integrated into a CI/CD pipeline, where every change triggers a series of tests, including plan review, policy validation, and unit tests, to ensure that no breakage is introduced.