AWS Certified Solutions Architect – Professional — Question 331

A company has a primary Amazon S3 bucket that receives thousands of objects every day. The company needs to replicate these objects into several other S3 buckets from various AWS accounts. A solutions architect is designing a new AWS Lambda function that is triggered when an object is created in the main bucket and replicates the object into the target buckets. The objects do not need to be replicated in real time. There is concern that this function may impact other critical
Lambda functions due to Lambda's regional concurrency limit.
How can the solutions architect ensure this new Lambda function will not impact other critical Lambda functions?

Answer options

• A. Set the new Lambda function reserved concurrency limit to ensure the executions do not impact other critical Lambda functions. Monitor existing critical Lambda functions with Amazon CloudWatch alarms for the Throttles Lambda metric.
• B. Increase the execution timeout of the new Lambda function to 5 minutes. Monitor existing critical Lambda functions with Amazon CloudWatch alarms for the Throttles Lambda metric.
• C. Configure S3 event notifications to add events to an Amazon SQS queue in a separate account. Create the new Lambda function in the same account as the SQS queue and trigger the function when a message arrives in the queue.
• D. Ensure the new Lambda function implements an exponential backoff algorithm. Monitor existing critical Lambda functions with Amazon CloudWatch alarms for the Throttles Lambda metric.

Correct answer: A

Explanation

By setting a reserved concurrency limit on the new AWS Lambda function, you establish a maximum cap on its concurrent executions, preventing it from consuming the entire regional concurrency pool and starving other critical functions. Additionally, monitoring the Throttles metric with Amazon CloudWatch alarms allows administrators to quickly detect and respond to any throttling issues in critical workloads. Other options, such as increasing execution timeouts or using exponential backoff, do not directly limit concurrency usage and will not protect the regional limit from being exhausted.