Amazon Web Services DOP-C02 Exam With Confidence Using Practice Dumps

Option B is the correct choice and has the least operational overhead because ECR lifecycle policies are the native, managed feature built specifically to automate image cleanup:

ECR lifecycle policies can expire images based on image age (e.g., images older than X days) and can also enforce retaining a minimum number of images (count-based retention), which directly matches the requirement “retain at least a specified number of images.”

Lifecycle policies work for both tagged and untagged images using rule selection and tagging status filters, so the repository stays clean without custom automation.

Why the other options are not appropriate / higher overhead:

A is invalid: ECR is not S3; S3 lifecycle policies do not manage ECR images .

C and D introduce custom automation (Lambda or SSM scripting), scheduling, permissions, error handling, retries, logging, and ongoing maintenance—higher overhead than a managed lifecycle policy.

To prevent developers from unintentionally attaching an Elastic IP address to an Amazon EC2 instance in production, the best approach is to use IAM policies and AWS Config rules. By attaching an IAM policy that denies the associate-address permission to the developers’ IAM group, you ensure that developers cannot perform this action. Additionally, creating a custom AWS Config rule to check for Elastic IP addresses associated with instances tagged as production provides ongoing monitoring. If the rule detects an Elastic IP address, it can trigger an alert to notify the security team. This method is proactive and enforces the necessary permissions while also providing a mechanism for detection and notification. References: from Amazon DevOps sources

The key requirement is to prevent non-approved EC2 instance types from being created at stack creation time , specifically when developers deploy AWS CloudFormation stacks. This is a pre-deployment enforcement requirement, not a detection or remediation requirement after resources already exist.

CloudFormation Guard Hooks are purpose-built for this use case. They allow organizations to define policy-as-code rules that validate CloudFormation templates before resources are created or updated. By writing a CloudFormation Guard rule that explicitly checks the InstanceType property against an approved allow list, the stack operation will fail immediately if a developer attempts to use a disallowed instance type. This enforces compliance early in the deployment lifecycle and avoids post-deployment cleanup.

Option B uses AWS Config, which only detects noncompliance after resources are created. Even with remediation, the instance would still be launched briefly, which violates the requirement. Option C uses an SCP, which applies broadly to all EC2 launches in the organization and is not limited to CloudFormation stacks; this is overly restrictive and could unintentionally block other valid use cases. Option A incorrectly combines Lambda with Guard Hooks—Guard Hooks natively evaluate Guard rules and do not invoke Lambda functions.

Therefore, using a CloudFormation Guard rule with a Guard Hook is the correct and AWS-recommended solution for enforcing approved EC2 instance types during CloudFormation deployments.