Assign Elastic IPs for `nlb`

[efekarakus]

Ask

The Load Balanced Web Service manifest supports the creation of a Network Load Balancer with the nlb field. However, today you cannot assign an elastic IP to the NLB.
This is particularly useful when another system that calls the NLB only has a set of allowlisted IP addresses that it accepts responds from. By assigning an elastic IP to the NLB, then the endpoints of the load balancer become deterministic.

Implementation

https://stackoverflow.com/a/57657411/1201381

Gitter

This feature was originally asked on Gitter: https://gitter.im/aws/copilot-cli?at=633c4cc9b4ccef19d022ca45

[efekarakus]

My intuition says that this feature would be useful with imported VPCs and setups where elastic IP addresses already exist ahead of time. So we would need to import them. I've asked on gitter for validation.

Perhaps a setup like this with work to dynamically fetch elastic IP addresses:

nlb:
  elastic_ips:
     from_tags:
        key: value