Скачать или смотреть How to Properly Use Terraform to Provision Security Groups for ElasticSearch in AWS

Discover effective strategies to manage AWS security groups using `Terraform`, particularly for ElasticSearch deployments across multiple VPCs. Learn how to troubleshoot and customize modules to meet your security needs.
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This video is based on the question https://stackoverflow.com/q/66701065/ asked by the user 'Melissa Jenner' ( https://stackoverflow.com/u/14005291/ ) and on the answer https://stackoverflow.com/a/66768957/ provided by the user 'Melissa Jenner' ( https://stackoverflow.com/u/14005291/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Properly Use Terraform to Provision Security Groups for ElasticSearch in AWS

When working with AWS, one common challenge is effectively managing the security groups required for different services, such as ElasticSearch. This becomes even more complicated when several Virtual Private Clouds (VPCs) are involved. In this guide, we will discuss a specific issue related to provisioning security groups for ElasticSearch using Terraform, and how you can resolve it.

The Problem

In a recent scenario, a user utilized Terraform to provision security groups for an ElasticSearch instance installed in VPC-A, while other VPCs (VPC-B and VPC-C) needed to connect to it. Manually configured security rules were as follows:

Inbound Rules

VPC-A: All Traffic from 40.10.0.0/16

VPC-B: All Traffic from 20.10.0.0/16

VPC-C: All Traffic from 30.10.0.0/16

Outbound Rules

Destination: All Traffic to 0.0.0.0/0

Despite the successful manual configuration, the Terraform code provided did not establish the necessary rules, leading to connection failures from VPC-B and VPC-C to ElasticSearch hosted in VPC-A.

Original Terraform Code

The initial Terraform configuration looked like this:

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

Upon execution, the code only set up the following rules:

Issues with Provoked Security Groups

Inbound: Security groups were incorrectly set, allowing only TCP traffic and not meeting the all-traffic requirement.

Outbound: Similar misconfigurations were present.

The Solution

The root of the problem lay in limitations related to the ElasticSearch module being utilized with Terraform. After much practice, the user figured out how to customize the security groups effectively to mimic the original manually provisioned rules.

Steps to Resolve the Issue

Download the ElasticSearch Module: Instead of relying on the external module directly, download it to your local setup.

Modify Security Group Configurations: Tailor the security group settings in the module to ensure they align with your previously successful manual configurations. Specifically, focus on:

Ingress rules that allow all traffic from the specified CIDR blocks.

Egress rules designed for unrestricted outbound traffic.

Replace the Original Module Reference: After making the necessary changes, link your modified version rather than the default provided by the module.

Test the Configuration: After implementing the modified module, apply your infrastructure changes and verify that VPC-B and VPC-C can correctly access the ElasticSearch instance in VPC-A.

By following these steps, the user effectively resolved the issue, allowing seamless interaction across all VPCs as originally designed.

Conclusion

Managing AWS resources with Terraform can present complex challenges, particularly when security group configurations are necessary across multiple VPCs. If you find yourself in a similar situation as described, don't hesitate to customize the modules you use. Sometimes, a little adjustment can lead to the resolution of seemingly insurmountable challenges. Happy coding!