ATM the Single-Node ASG module includes support for an EBS volume that is associated with the ASG. Another use-case we run into is attaching an Elastic IP (EIP). Similar to the EBS volume, this is easy to attach to a single EC2 instance, but Terraform cannot do that for an EC2 instance that does not exist yet (eg when the EC2 instance is created by an ASG). We solve this in the same way as with the EBS volume - we give EC2 init enough info to attach the EIP when booting the instance.

Requirements

• Update the single-node-asg module to add support for EIP in the same way the EBS volume is supported.
• Make the EIP optional, use a variable/local combination to enable/disable the resource with true/false --> 1/0
• Propose and review a method for attaching during init before implementing.
• Update an example project (in this repo) that uses the single-node-asg module, for TDD and to demonstrate how it works.