Amazon ECR service-linked role for pull through cache

Amazon ECR uses a service-linked role named AWSServiceRoleForECRPullThroughCache which gives permission for Amazon ECR to perform actions on your behalf to complete pull through cache actions. For more information about pull through cache, see Using pull through cache rules.

Service-linked role permissions for Amazon ECR

The AWSServiceRoleForECRPullThroughCache service-linked role trusts the following service to assume the role.

• pullthroughcache.ecr.amazonaws.com

Permissions details

The AWSECRPullThroughCache_ServiceRolePolicy permissions policy is attached to the service-linked role. This managed policy grants Amazon ECR permission to perform the following actions. For more information, see AWSECRPullThroughCache_ServiceRolePolicy.

• ecr – Allows the Amazon ECR service to push images to a private repository.

• secretsmanager:GetSecretValue – Allows the Amazon ECR service to retrieve the encrypted contents of an AWS Secrets Manager secret. This is required when using a pull through cache rule to cache images from an upstream registry that requires authentication in your private registry. This permission applies only to secrets with the ecr-pullthroughcache/ name prefix.

The AWSECRPullThroughCache_ServiceRolePolicy policy contains the following JSON.

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "ECR",
            "Effect": "Allow",
            "Action": [
                "ecr:GetAuthorizationToken",
                "ecr:BatchCheckLayerAvailability",
                "ecr:InitiateLayerUpload",
                "ecr:UploadLayerPart",
                "ecr:CompleteLayerUpload",
                "ecr:PutImage"
            ],
            "Resource": "*"
        },
        {
            "Sid": "SecretsManager",
            "Effect": "Allow",
            "Action": [
                "secretsmanager:GetSecretValue"
            ],
            "Resource": "arn:aws:secretsmanager:*:*:secret:ecr-pullthroughcache/*",
            "Condition": {
                "StringEquals": {
                    "aws:ResourceAccount": "${aws:PrincipalAccount}"
                }
            }
        }
    ]
}

You must configure permissions to allow an IAM entity (for example a user, group, or role) to create, edit, or delete a service-linked role. For more information, see Service-linked role permissions in the IAM User Guide.

Creating a service-linked role for Amazon ECR

You don't need to manually create the Amazon ECR service-linked role for pull through cache. When you create a pull through cache rule for your private registry in the AWS Management Console, the AWS CLI, or the AWS API, Amazon ECR creates the service-linked role for you.

If you delete this service-linked role and need to create it again, you can use the same process to recreate the role in your account. When you create a pull through cache rule for your private registry, Amazon ECR creates the service-linked role for you again if it doesn't already exist.

Editing a service-linked role for Amazon ECR

Amazon ECR doesn't allow manually editing the AWSServiceRoleForECRPullThroughCache service-linked role. After the service-linked role is created, you can't change the name of the role because various entities might reference the role. However, you can edit the description of the role using IAM. For more information, see Editing a service-linked role in the IAM User Guide.

Deleting the service-linked role for Amazon ECR

If you no longer need to use a feature or service that requires a service-linked role, we recommend that you delete that role. That way, you don’t have an unused entity that isn't actively monitored or maintained. However, you must delete the pull through cache rules for your registry in every Region before you can manually delete the service-linked role.

Note

If you try to delete resources while the Amazon ECR service is still using the role, your delete action might fail. If that happens, wait for a few minutes and try again.

To delete Amazon ECR resources used by the AWSServiceRoleForECRPullThroughCache service-linked role

1. Open the Amazon ECR console at https://console.aws.amazon.com/ecr/.

2. From the navigation bar, choose the Region where your pull through cache rules are created.

3. In the navigation pane, choose Private registry.

4. On the Private registry page, on the Pull through cache configuration section, choose Edit.

5. For each pull through cache rule you have created, select the rule and then choose Delete rule.

To manually delete the service-linked role using IAM

Use the IAM console, the AWS CLI, or the AWS API to delete the AWSServiceRoleForECRPullThroughCache service-linked role. For more information, see Deleting a Service-Linked Role in the IAM User Guide.