You are developing an application using a microservices architecture. Some serverless AWS services such as Lambda, SQS and DynamoDB are used. One Lambda Function is deployed to reset users’ passwords, but it does not run frequently. When the function is inactive and called, it may take a longer time to handle the requests. You want to minimize the processing time for the function. Which of the following Lambda "features" you can use to get greater control over the performance of your serverless applications at any scale?

Answer options:

A.For the Lambda Function, avoid using languages such as Java that need a long compilation time. Use Node.js or Python instead.
B.Configure a CloudWatch Event rule and select the Lambda Function as its target. The event is executed every minute to warm up the function so that the function stays active.
C.Configure the Lambda Function to use "Provisioned Concurrency" always to stay active so that the Lambda container does not get reused by AWS.
D.Create a CloudWatch alarm to monitor the invocations of the function. If there are no invocations for 1 hour, trigger the alarm to call the Lambda Function so that the function stays warm.
 

Correct Answer – C
If the Lambda Function is not used for a long time, AWS may recycle the container. And if there are new requests to the function, AWS needs to deploy the container again for the function. In order to pre-warm the Lambda function, the best way is to use the "Provisioned Concurrency" which is a "feature" of the Lambda function.
https://aws.amazon.com/about-aws/whats-new/2019/12/aws-lambda-announces-provisioned-concurrency/
Options A, B and D are incorrect: Because these are NOT a "feature" of the Lambda function.