Option A is incorrect because setting the deployment configuration to LambdaAllAtOnce means that
the new version of the application will be deployed to all Lambda functions at once, affecting all
customers. This does not meet the requirement of affecting the fewest customers possible.
Moreover, configuring automatic rollbacks on the deployment group is not operationally efficient, as
it requires manual intervention to fix the errors and redeploy the application.
Option B is correct because setting the deployment configuration to
LambdaCanary10Percent10Minutes means that the new version of the application will be deployed
to 10 percent of the Lambda functions first, and then to the remaining 90 percent after 10 minutes.
This minimizes the impact of errors on customers, as only 10 percent of them will be affected by a
faulty deployment. Configuring automatic rollbacks on the deployment group also meets the
requirement of reverting to the most recent stable version of the application when an error is
detected. Creating a CloudWatch alarm that detects HTTP Bad Gateway errors on API Gateway is a
valid way to monitor the health of the application and trigger a rollback if needed.
Option C is incorrect because setting the deployment configuration to LambdaAllAtOnce means that
the new version of the application will be deployed to all Lambda functions at once, affecting all
customers. This does not meet the requirement of affecting the fewest customers possible.
Moreover, configuring manual rollbacks on the deployment group is not operationally efficient, as it
requires human intervention to stop the current deployment and start a new one. Creating an SNS
topic to send notifications every time a deployment fails is not sufficient to detect errors in the
application, as it does not monitor the API Gateway responses.
Option D is incorrect because configuring manual rollbacks on the deployment group is not
operationally efficient, as it requires human intervention to stop the current deployment and start a
new one. Creating a metric filter on a CloudWatch log group for API Gateway to monitor HTTP Bad
Gateway errors is a valid way to monitor the health of the application, but invoking a new Lambda
function to perform a rollback is unnecessary and complex, as CodeDeploy already provides
automatic rollback functionality.
