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

Why Option A is Correct:Creating a CloudWatch metric filter with " ERROR " as the search term ensures that occurrences of the word " ERROR " in logs are counted. An alarm can then be set to notify the SNS topic when the count exceeds 1. This is the standard approach to monitor specific patterns in CloudWatch Logs.

Why Other Options are Incorrect:

Option B: CloudWatch Logs Insights is used for querying logs manually and does not integrate directly with alarms for automated notifications.

Option C: SNS subscription filters are not a feature for filtering log patterns in CloudWatch Logs.

Option D: CloudWatch alarms do not directly include log filter patterns; a metric filter is needed to create the metric first.

AWS Documentation References:

Creating CloudWatch Metric Filters

The correct answer is C because AWS AppConfig provides built-in support for feature flags , allowing developers to enable or disable features dynamically without redeploying application code. This is exactly what the question requires: keeping features hidden from end users until the features are ready for release, and then selectively activating them when appropriate.

AWS documentation describes AppConfig as a service for managing application configuration in a safe and controlled way. Feature flags in AppConfig let teams separate deployment from release , which is a core best practice in modern application development. A developer can deploy code that contains unfinished or hidden functionality, while the actual visibility and activation of that functionality is controlled through feature flag values stored in an AppConfig configuration profile. When the feature is ready, the flag can be turned on without changing the application package.

Option A is incorrect because AWS AppSync is a managed GraphQL service and is not the AWS feature flag service for application configuration management. Option B is incorrect because DynamoDB Streams are used for capturing item-level changes and reacting to table updates, not for controlled feature activation. Option D is incorrect because Amplify DataStore is intended for client-side data synchronization and offline access patterns, not centralized production feature flag management.

Using AppConfig also provides operational benefits such as deployment strategies, configuration validation, and rollback support, which make it safer than building a custom feature toggle mechanism. For these reasons, AWS AppConfig feature flags are the most appropriate and AWS-recommended solution for hiding prerelease features and selectively enabling them later.

Therefore, C is the correct answer.

AWS IAM role permissions are evaluated dynamically . According to AWS documentation, when an IAM role attached to an EC2 instance is updated, the updated permissions are available to applications running on that instance without requiring a restart . The EC2 instance retrieves temporary credentials through the instance metadata service, and those credentials are refreshed automatically.

In this scenario, the least disruptive approach is to update the IAM role policy to include the required s3:GetObject permission. Once the permission is added, the application can immediately retry access to the S3 bucket without restarting, stopping, or terminating the EC2 instance.

Terminating or restarting the instance (Options A and C) introduces unnecessary downtime and operational overhead. Modifying the S3 bucket policy (Option D) is unnecessary because the problem lies with missing role permissions, not bucket access configuration.

AWS best practices strongly recommend using IAM roles for EC2 and updating permissions dynamically to avoid service interruption. Therefore, simply adding the required permission to the role is the correct and most efficient solution.