How to Use count in Terraform for Multiple DNS Zones Based on Conditions

Description

Learn how to effectively manage DNS zones in Terraform using the `count` parameter with conditional logic. This guide simplifies the process of creating multiple private DNS zones based on environment variables. --- This video is based on the question https://stackoverflow.com/q/67639489/ asked by the user 'mayank arora' ( https://stackoverflow.com/u/9233807/ ) and on the answer https://stackoverflow.com/a/67640147/ provided by the user 'Matthew Schuchard' ( https://stackoverflow.com/u/5343387/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions. Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: terraform count index and length Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/licensing The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/by-sa/4.0/ ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/by-sa/4.0/ ) license. If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com. --- Creating Multiple Private DNS Zones with Terraform Have you ever needed to create multiple private DNS zones in Terraform based on certain conditions? This can be particularly challenging if you are trying to handle multiple environments such as Dev, QA, UAT, and Prod. In this guide, we will walk you through the solution to use the count parameter effectively in Terraform to manage resource creation based on specified environments. Let’s dive in! Understanding the Problem You need to create several private DNS zones for your non-production and production environments: Non-Production Environments: Dev, QA, UAT Production Environments: Prod, DR However, you want the resource to be created only if a boolean variable is_nonprod is set to 1 (true). The challenge is to use the count parameter twice: once to check the boolean and once to get the length of the list of environments. The Error Encountered In your initial attempt, you encountered this error: [[See Video to Reveal this Text or Code Snippet]] This indicates that the expression used in your count definition mixes incompatible types (a boolean with a number). Solution Overview Instead of the original expression you used: [[See Video to Reveal this Text or Code Snippet]] You should structure it as follows: [[See Video to Reveal this Text or Code Snippet]] This ensures that you are providing a consistent numeric result to the count parameter, allowing the resource creation to proceed based on the given conditions. Step-by-Step Solution Define Your Variables: In your variable file, declare your environment list and the boolean variable for non-production: [[See Video to Reveal this Text or Code Snippet]] Specify Your Environment Variables: In your .tfvars file, list the environments as required: [[See Video to Reveal this Text or Code Snippet]] Implement Your Resource Block: Here is how you can implement your azurerm_private_dns_zone resource to create the DNS zones based on the conditions specified: [[See Video to Reveal this Text or Code Snippet]] Key Points to Remember Use Proper Conditional Logic: Ensure that the outcome of your logic generates a consistent numeric type for the count parameter. Avoid Repetition: Each argument should be set only once within a resource block to prevent errors. Validate Your Environment: Test the configurations in a controlled environment to see if they behave as expected. Conclusion Using the count parameter effectively in Terraform allows for dynamic and conditional resource management. By structuring your expressions properly and understanding the types required for your conditions, you can easily handle scenarios like creating multiple private DNS zones based on environment settings. Following the steps outlined in this guide should help you navigate similar challenges in your Terraform configurations. Feel free to reach out with questions or comments about your experiences using Terraform!