Amazon Web Services DOP-C02 Online Access

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.

" AWS CodeArtifact operates in multiple Availability Zones and stores artifact data and metadata in Amazon S3 and Amazon DynamoDB. Your encrypted data is redundantly stored across multiple facilities and multiple devices in each facility, making it highly available and highly durable. " With no internet connectivity, a gateway endpoint becomes necessary to access S3.

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The correct answer is B because AWS Config can continuously evaluate the account-level S3 Block Public Access configuration by using a managed rule. When the configuration becomes noncompliant, AWS Config can trigger automatic remediation through an AWS Systems Manager Automation runbook to restore the required settings.

This solution directly satisfies both requirements:

Detect changes to account-level S3 public access settings.

Automatically revert those changes so that all public access is blocked again.

Why the other options are incorrect:

A. Security Hub is primarily for aggregated security findings and controls visibility. It is not the most direct or standard service for continuous configuration evaluation with automatic remediation of this specific setting.

C. An SCP can restrict permissions, but it does not automatically detect and revert changes to S3 Block Public Access settings.

D. Amazon Macie is for discovering and protecting sensitive data, not for continuously enforcing and remediating S3 Block Public Access account settings.

This failure is typically due to incorrectly configured health checks in Elastic Load Balancing for the Classic Load Balancer, Application Load Balancer, or Network Load Balancer used to manage traffic for the deployment group. To resolve the issue, review and correct any errors in the health check configuration for the load balancer.