A Terraform module that performs a local docker pull and push to a given AWS ECR repository
In late 2020, Docker Hub announced that the Hub service would begin limiting the rate at which images can be pulled under their anonymous and free plans.
The AWS recommendation for those not wishing to upgrade to a paid plan is to mirror the Dockerhub image to their own AWS ECR repository.
This simple task requires a basic 'pull from Dockerhub-push to ECR' loop for which there exists no simple bootstrapping solution. The typical use case is a new ECR repository that would look to use a Dockerhub image as its 'base' image which can then be used in subsequent builds without the pull limits.
This module is a simple terraform local-exec provisioner which runs the required awscli and docker push commands to ECR, and can be woven in to your existing set-up.
- aws-cli v2 installed and configured with a named profile that has permissions to push to the desired ECR repository
- Docker installed on the machine executing terraform, and permissions for the user executing terraform to run docker commands (e.g. by adding the user to the 'docker' user group)
As this module is essentially running a series of bash commands, it ensures idempotence by triggering only when any of the values of the docker_source, ecr_repo_name or ecr_repo_tag variables are changed.
module "ecr_mirror" {
source = "TechToSpeech/ecr-mirror/aws"
aws_account_id = "123456544225"
aws_region = "eu-west-1"
docker_source = "wordpress:php7.4-apache"
aws_profile = "default"
ecr_repo_name = "php_wordpress"
ecr_repo_tag = "base"
}
Consider adding an additional depends_on attribute if you are using this module in combination with a Terraform resource that also creates the ECR repository being pushed to.
Licensed under the Apache License, Version 2.0 (the "License").
You may obtain a copy of the License at apache.org/licenses/LICENSE-2.0.
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