It seems like there might be a confusion in the terminology. "Rehydration" typically refers to the process of restoring or replenishing something with water. In the context of Terraform and infrastructure as code (IaC), there isn't a direct concept of "rehydration." Although a problem with Infrastructure may necessitate a refresh/rehydration of infrastructure using terraform. Failures of tf configurations to update, abnormal termination of tf provisioning, errors picked up in tf logs/history db may necessitate a retry/rerun of tf. A system that is underperforming or inactive/zombied, or not showing recent change updates or not showing up in monitoring and observalibility may require some troubleshooting and correction to tf files and a rehydrate operation(create new, destroy bad/old infra).
First here's some guidance on best practices related to managing infrastructure with Terraform, and if you have a specific scenario or term in mind, feel free to provide more details.
- Use Version Control: Store your Terraform configurations in a version control system (e.g., Git) to track changes and enable collaboration.
- Separation of Concerns: Organize your Terraform code into modules based on logical components and responsibilities. This promotes reusability and maintainability.
- Immutable Infrastructure: Follow the principle of immutable infrastructure, where changes to infrastructure are achieved by creating new resources rather than modifying existing ones.
- Variable Management: Use variables to parameterize your Terraform configurations. This allows for flexibility in different environments and promotes reuse.
- Environment-specific Configuration: Separate environment-specific configurations (dev, uat, prod, etc.) to manage differences between environments effectively.
- Automate Testing: Implement automated testing for your Terraform configurations using tools like Terratest to catch issues early in the development lifecycle.
- Version Pinning: Pin versions of provider plugins and Terraform itself to avoid unexpected changes when updating.
- Secrets Management: Use a secure method for managing secrets and sensitive information, such as HashiCorp Vault or AWS Secrets Manager.
- Documentation: Document your Terraform code, especially complex modules or configurations, to help others understand and maintain the code.
- Resource Tagging: Implement consistent resource tagging to aid in tracking and management. This is important for FinOps of cloud infra.
- Error Handling: Implement error handling mechanisms in your scripts to handle failures gracefully.
Sometimes "rehydration" may mean refreshing or updating existing infrastructure using terraform, you can use the following practices:
- Terraform Plan: Always run terraform plan before applying changes to understand the impact of modifications.
- Resource Replacement: When making changes, be aware of which modifications may require resource replacement. Terraform will indicate this in the execution plan.
- Lifecycle Hooks: Leverage lifecycle hooks to perform actions during the lifecycle of a resource (e.g., create_before_destroy for seamless replacement).
- Taint and Replace: In some cases, you might use terraform taint to mark a resource as "tainted," which will force Terraform to recreate it on the next apply.
Remember to thoroughly test changes in a LLE, non-production environment before applying them in production. The exact best practices may depend on the specific use case or scenario you have in mind, so feel free to provide more details for more targeted guidance.
