Define Elastic Container Registry (ECR) lifecycle policy

[matthew-a-carr]

Overview

The beacons webapp/service project CI/CD pipelines push a new container image up to ECR on every commit. The reason for this is to allow Terraform to re-deploy the images easily when there is a change to the images. However, this does mean that the container registry will start to incur costs if we allow it to grow without a lifecycle policy in place.

AWS ECR Pricing Tier

AWS provides you with 500MB of free storage and then charges $0.10 per GB every month, see pricing.

As of 12/02/2020, we have:

• 16GB webapp (260 images at ~63MB)
• 9GB service (63 images at ~130MB)

Total: ~ $2.5 a month

This is over ~2 weeks of 4 devs full time so scaling out, based on that rate of increase, to a year will be:

($2.5 * 2 * 12) = $60 a year

Other Considerations

AWS provides 50GB of free storage for public ECR registries, this would effectively reduce the cost by $5 per year ($0.1*50GB = $5)

[andiempett]

@WillGibson has a lifecycle policy been implemented? i cant see one in the codebase. It looks like the ECR repo is managed outside this terraform stack see here

might be some cost savings/tidying up to be had here