AWS Serverless Computing 5

Question 1

A Lambda function processing SQS messages fails on one record in a batch. By default, what happens to the entire batch?

Accepted Answer

The entire batch is returned to the queue and retried

Answer

By default, if a Lambda function throws an error, the entire batch is considered failed and all messages return to the queue for retry.

Question 2

Which AWS Lambda scaling behavior is controlled by Reserved Concurrency?

Accepted Answer

It sets a hard maximum on the number of concurrent executions for that function

Answer

Reserved Concurrency caps the maximum concurrent executions for a specific function, preventing it from consuming the account-wide limit.

Question 3

An API Gateway HTTP API needs to authenticate users via JWT tokens issued by Amazon Cognito. What feature should be configured?

Accepted Answer

JWT Authorizer

Answer

HTTP APIs support JWT Authorizers that validate tokens directly from any OIDC-compliant issuer including Cognito without a Lambda function.

Question 4

What is the purpose of AWS Lambda Power Tuning tool?

Accepted Answer

Finds the optimal memory/CPU configuration balancing cost and performance

Answer

Lambda Power Tuning runs your function at multiple memory settings and visualizes the cost-performance tradeoff to find the optimal configuration.

Question 5

Which Step Functions workflow type supports high-volume event processing at a lower cost but does NOT support activities or some advanced features?

Accepted Answer

Express Workflows

Answer

Express Workflows are optimized for high-volume, short-duration workloads and are priced per execution duration rather than per state transition.

AWS Practice Test