How can the solutions architect ensure this new Lambda function will not impact other critical Lambda functions?
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.
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.
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.
Ensure the new Lambda function implements an exponential backoff algorithm. Monitor existing critical Lambda functions with Amazon CloudWatch alarms for the Throttles Lambda metric.
Explanations:
Setting a reserved concurrency limit for the new Lambda function ensures that it will not exceed a defined number of concurrent executions, thereby protecting the concurrency available for other critical Lambda functions. Monitoring with CloudWatch alarms for throttling can provide insights into whether the limits are appropriate.
Increasing the execution timeout does not prevent the new Lambda function from impacting other functions. It only allows the function to run longer if needed but does not control the concurrency level, which is critical in this scenario.
While using an SQS queue decouples the triggering of the Lambda function from the S3 event, the new Lambda function will still need to scale and could potentially affect other functions if there are too many messages in the queue. Additionally, placing it in a different account does not inherently protect other functions in the primary account.
Implementing an exponential backoff algorithm is useful for retrying failed executions but does not prevent the new Lambda function from consuming concurrency, which could still impact other critical Lambda functions if they are triggered simultaneously.
I compute that the answer is:
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.