AWS Certified Developer – Associate (DVA-C02)Development with AWS ServicesHard
A developer is creating a serverless API using Amazon API Gateway and AWS Lambda. The API needs to handle varying loads, from zero requests per second to thousands of requests per second, with minimal cold start latency for the Lambda functions. The developer wants to ensure that a certain number of Lambda execution environments are always initialized and ready to respond instantly. Which Lambda feature should be configured?
- AProvisioned Concurrency
- BMaximum Concurrency
- CLambda Aliases
- DReserved Concurrency
Show answer & explanationAnswer & explanation
Correct answer: A. Provisioned Concurrency
Provisioned Concurrency initializes a requested number of execution environments in advance, so they are ready to respond immediately to API Gateway requests, significantly reducing cold start latency for critical functions that need instant responses.
Why the other options are wrong
- B. Maximum Concurrency sets an upper limit on the number of concurrent executions for a function, preventing it from consuming too much account concurrency, but doesn't address cold starts.
- C. Lambda Aliases are pointers to specific versions of a Lambda function and are used for deployment strategies (e.g., blue/green), not for managing cold start latency directly.
- D. Reserved Concurrency guarantees that a function always has a certain amount of concurrency available, preventing other functions from consuming all available concurrency, but it does not keep environments warm to prevent cold starts.
Lambda Provisioned Concurrency
A feature that keeps function execution environments initialized and ready to respond to requests, reducing cold start latency for critical serverless applications.
- Pre-initializes a specified number of execution environments.
- Eliminates cold start latency for provisioned environments.
- You pay for the configured concurrency even when idle.
Memory trick: Provisioned Concurrency gets Lambda ready before the call.