top of page
  • Writer's pictureShaked Braimok Yosef

Backward Compatibility is a MUST in IaC

Ensuring backward compatibility in infrastructure code, particularly in tools like Terraform, is paramount for a seamless and reliable deployment process, especially in the face of evolving environments and changing infrastructure requirements.

This article outlines essential best practices to help you achieve and maintain backward compatibility:

1. Use Version Control:

  • Employ a version control system like Git to manage your infrastructure code. This enables you to track changes over time and easily roll back to previous versions if necessary.

2. Semantic Versioning:

  • Adhere to semantic versioning (SemVer) for your infrastructure code. Increment versions based on the nature of changes: major for incompatible modifications, minor for backward-compatible additions, and patch for backward-compatible bug fixes.

3. Module Versioning:

  • When using Terraform modules, ensure proper versioning. This practice safeguards against inadvertent breaks in existing deployments when changes are made to modules.

4. Documentation:

  • Keep comprehensive and up-to-date documentation. Clearly document any changes that introduce backward incompatibilities and provide instructions on how to update existing deployments.

5. Variable Defaults and Required Variables:

  • Exercise caution when changing variable defaults or introducing new required variables. Clearly communicate such changes and provide migration steps for existing deployments.

6. Input and Output Variables:

  • When modifying input or output variables, avoid removing or renaming existing ones. If changes are necessary, deprecate the old variables over time rather than immediately removing them.

7. Conditional Logic:

  • Use conditional logic judiciously and be mindful of how changes might impact existing deployments. Introduce new conditional logic carefully, ensuring it doesn’t break existing configurations.

8. Feature Flags:

  • Implement feature flags or conditional blocks in your code to selectively enable or disable new features. This allows for a gradual rollout of changes and provides the flexibility to roll back if issues arise.

9. Automated Testing:

10. Backward Compatibility Testing:

  • Prioritize backward compatibility testing as part of your deployment pipeline. Test upgrades on environments closely resembling your production setup to identify and address issues before deploying to production.

11. User Feedback:

  • Encourage feedback from users managing the infrastructure. Their insights can uncover issues that automated testing might miss, providing valuable information on the impact of changes.

By following these best practices, you can minimize the risk of introducing backward incompatibilities in your Terraform infrastructure code, making it easier for your team to manage and evolve the infrastructure over time.

Learn more:


bottom of page