How to Efficiently Add Multiple SSL Certificates to ALB Listeners in Terraform

Описание: Discover the best practices for adding multiple SSL certificates to Application Load Balancer (ALB) listeners using Terraform foos, enhancing your AWS infrastructure management effectively.
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This video is based on the question https://stackoverflow.com/q/66268417/ asked by the user 'Darren White' ( https://stackoverflow.com/u/2604071/ ) and on the answer https://stackoverflow.com/a/66269265/ provided by the user 'Marcin' ( https://stackoverflow.com/u/248823/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Efficiently Add Multiple SSL Certificates to ALB Listeners in Terraform

When working with AWS and Terraform, managing SSL certificates associated with Application Load Balancer (ALB) listeners can be a complex task, particularly when multiple certificates are involved. This guide will walk you through a clear solution to efficiently add multiple SSL certificates to ALB listeners using Terraform's for loop constructs.

The Problem Statement

As cloud applications grow, the need for secure communication increases, leading to the deployment of multiple SSL certificates across various listeners in an ALB. The challenge arises when attempting to manage these configurations effectively in Terraform, especially when trying to minimize code duplication.

Our goal is to leverage Terraform's capabilities to dynamically assign multiple SSL certificates across ALB listeners without cumbersome code.

Solution Overview

We can achieve this by using Terraform's mapping capabilities and for_each loop mechanisms. Below are the steps that will guide you through setting up ALB listeners with multiple SSL certificates:

Step 1: Define Your ALB Listeners

First, you need to establish your ALB listeners using a variable map for cleaner configuration. Here’s a simple example of how you can define your ALB listener:

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Step 2: Define Your Additional SSL Certificates

Next, we initiate a variable containing your additional SSL certificates. Instead of a simple list, we can utilize a map where keys correspond to the ports used in the ssl_forwarding variable.

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Step 3: Add SSL Certificates to the Listeners

With your listeners and certificates defined, we can now proceed to attach multiple certificates to each listener using the for_each construct.

[[See Video to Reveal this Text or Code Snippet]]

Step 4: Flattening the Certificates

To facilitate the use of for_each, we need to flatten our certificates variable. This can be achieved with a local value:

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Complete Code Example

Here is how everything comes together:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

By utilizing mapping variables and Terraform's for_each functionality, you can easily manage multiple SSL certificates across ALB listeners without excessive redundancy in your configurations. This flexible approach allows you to efficiently scale your AWS infrastructure while maintaining a secure communication environment.

Feel free to reach out with any questions, or share your experiences implementing SSL certificates with Terraform!