/aws-containers

Amazon Elastic Container Registry

Overview

Domain expertise for managing ECR registries and repositories, as well as pushing container images and other artifacts. Covers various topics.

Create Repository

aws ecr create-repository \
  --repository-name "$REPO_NAME" \
  --image-scanning-configuration scanOnPush=true \
  --image-tag-mutability IMMUTABLE \
  --encryption-configuration encryptionType=AES256 \
  --region "$REGION" \
  --output json

Deprecation notice: --image-scanning-configuration is being deprecated in favor of registry-level scanning configuration via put-registry-scanning-configuration (see Image Scanning section). The parameter still works but prefer the registry-level approach for new setups.

The operator SHOULD set:

• scanOnPush=true to automatically scan images for vulnerabilities on push (or configure scanning at the registry level — see Image Scanning).
• image-tag-mutability IMMUTABLE to prevent tag overwriting. This ensures a given tag always refers to the same image digest. Use IMMUTABLE_WITH_EXCLUSION with --image-tag-mutability-exclusion-filters if specific tags (e.g., latest) must remain mutable.

Authenticate and Push Images

Authenticate Docker to ECR

aws ecr get-login-password --region "$REGION" \
  | docker login --username AWS \
    --password-stdin "$ACCOUNT_ID.dkr.ecr.$REGION.amazonaws.com"

Warning: The authentication token expires after 12 hours. The operator MUST re-authenticate before pushing if the token has expired. CI/CD pipelines SHOULD call get-login-password at the start of every build.

Build, Tag, and Push

docker build -t "$REPO_NAME:$IMAGE_TAG" .
docker tag "$REPO_NAME:$IMAGE_TAG" \
  "$ACCOUNT_ID.dkr.ecr.$REGION.amazonaws.com/$REPO_NAME:$IMAGE_TAG"
docker push \
  "$ACCOUNT_ID.dkr.ecr.$REGION.amazonaws.com/$REPO_NAME:$IMAGE_TAG"

Verify the Push

aws ecr describe-images \
  --repository-name "$REPO_NAME" \
  --image-ids imageTag="$IMAGE_TAG" \
  --region "$REGION" \
  --output json

Image Scanning

Basic Scanning

Basic scanning has no separate ECR charge (only enhanced scanning incurs Inspector charges).

# Trigger a manual scan
aws ecr start-image-scan \
  --repository-name "$REPO_NAME" \
  --image-id imageTag="$IMAGE_TAG" \
  --region "$REGION" \
  --output json

# Retrieve scan findings
aws ecr describe-image-scan-findings \
  --repository-name "$REPO_NAME" \
  --image-id imageTag="$IMAGE_TAG" \
  --region "$REGION" \
  --output json

See the relevant documentation for more information.

Enhanced Scanning with Amazon Inspector

Enhanced scanning provides continuous, automated scanning using Amazon Inspector. It covers OS packages and programming language packages.

The operator MUST enable enhanced scanning at the registry level:

aws ecr put-registry-scanning-configuration \
  --scan-type ENHANCED \
  --rules '[{"scanFrequency":"CONTINUOUS_SCAN","repositoryFilters":[{"filter":"*","filterType":"WILDCARD"}]}]' \
  --region "$REGION" \
  --output json

Enhanced scanning incurs additional Inspector charges.

See the relevant documentation for more information.

Lifecycle policies

Amazon ECR lifecycle policies provide more control over the lifecycle management of images in a private repository. A lifecycle policy contains one or more rules, and each rule defines an action for Amazon ECR. Based on the expiration criteria in the lifecycle policy, images can be archived or expired based on the criteria specified in the lifecycle policy within 24 hours.

See the relevant documentation for more information.

Note: sinceImagePulled cannot expire images. When a user wants to clean up images based on last-pull time, be aware that the sinceImagePulled count type only works with the transition action (to the archive storage class) — it cannot be used with expire. To actually delete images by pull activity, use two rules: first transition them to archive with sinceImagePulled, then expire them with sinceImageTransitioned. Archived images must stay in archive for a minimum of 90 days before they can be deleted. Never produce a policy that pairs sinceImagePulled with an expire action.

Security Considerations

• Encryption at rest: Use KMS via --encryption-configuration when you need key-level audit trail (KMS logs GenerateDataKey, Decrypt calls in CloudTrail) and customer-managed key rotation. AES256 (S3-managed keys) is the default. All ECR API calls are logged by CloudTrail regardless of encryption type.
• Image tag immutability: Set IMMUTABLE to prevent tag overwriting attacks (supply chain security). Use IMMUTABLE_WITH_EXCLUSION only when specific tags must remain mutable.
• Least-privilege IAM: Scope ECR permissions to specific repository ARNs. Separate push (CI/CD) from pull (execution role) permissions. ecr:GetAuthorizationToken requires Resource: "*" — it cannot be scoped to a repository.
• Cross-account access: Use aws:PrincipalOrgID conditions in repository policies. Grant only ecr:BatchGetImage and ecr:GetDownloadUrlForLayer for pull-only access. Prefer specific role ARNs over :root principals.
• Logging and monitoring: ECR API calls are logged by CloudTrail. Set CloudWatch alarms on ECR API usage metrics to detect unusual pull patterns or approaching quota limits. See ECR usage metrics.
• Lifecycle policies: Expire untagged and old images to reduce attack surface from unpatched images.

Resources

• Amazon ECR Documentation
• IAM Reference