A developer uses AWS CloudFormation to deploy an Amazon API Gateway API and an AWS Step Functions state machine The state machine must reference the API Gateway API after the CloudFormation template is deployed The developer needs a solution that uses the state machine to reference the API Gateway endpoint.
Which solution will meet these requirements MOST cost-effectively?

1. A. Configure the CloudFormation template to reference the API endpoint in the DefinitionSubstitutions property for the AWS StepFunctions StateMachme resource.
2. B. Configure the CloudFormation template to store the API endpoint in an environment variable for the AWS::StepFunctions::StateMachine resourc Configure the state machine to reference the environment variable
3. C. Configure the CloudFormation template to store the API endpoint in a standard AWS: SecretsManager Secret resource Configure the state machine to reference the resource
4. D. Configure the CloudFormation template to store the API endpoint in a standard AWS::AppConfig;:ConfigurationProfile resource Configure the state machine to reference the resource.

Correct Answer: A
The most cost-effective solution is to use the DefinitionSubstitutions property of the AWS::StepFunctions::StateMachine resource to inject the API endpoint as a variable in the state machine definition. This way, the developer can use the intrinsic function
Fn::GetAtt to get the API endpoint from the AWS::ApiGateway::RestApi resource, and pass it to the state machine without creating any additional resources or environment variables. The other solutions involve creating and managing extra resources, such as Secrets Manager secrets or AppConfig configuration profiles, which incur additional costs and complexity. References
✑ AWS::StepFunctions::StateMachine - AWS CloudFormation
✑ Call API Gateway with Step Functions - AWS Step Functions
✑ amazon-web-services aws-api-gateway terraform aws-step-functions

A developer is migrating some features from a legacy monolithic application to use AWS Lambda functions instead. The application currently stores data in an Amazon Aurora DB cluster that runs in private subnets in a VPC. The AWS account has one VPC deployed. The Lambda functions and the DB cluster are deployed in the same AWS Region in the same AWS account.
The developer needs to ensure that the Lambda functions can securely access the DB cluster without crossing the public internet.
Which solution will meet these requirements?

1. A. Configure the DB cluster's public access setting to Yes.
2. B. Configure an Amazon RDS database proxy for the Lambda functions.
3. C. Configure a NAT gateway and a security group for the Lambda functions.
4. D. Configure the VPC, subnets, and a security group for the Lambda functions.

Correct Answer: D
This solution will meet the requirements by allowing the Lambda functions to access the DB cluster securely within the same VPC without crossing the public internet. The developer can configure a VPC endpoint for RDS in a private subnet and assign it to the Lambda functions. The developer can also configure a security group for the Lambda functions that allows inbound traffic from the DB cluster on port 3306 (MySQL). Option A is not optimal because it will expose the DB cluster to public access, which may compromise its security and data integrity. Option B is not optimal because it will introduce additional latency and complexity to use an RDS database proxy for accessing the DB cluster from Lambda functions within the same VPC. Option C is not optimal because it will require additional costs and configuration to use a NAT gateway for accessing resources in private subnets from Lambda functions.
References: [Configuring a Lambda Function to Access Resources in a VPC]

A developer is writing a serverless application that requires an AWS Lambda function to be invoked every 10 minutes.
What is an automated and serverless way to invoke the function?

1. A. Deploy an Amazon EC2 instance based on Linux, and edit its /etc/confab file by adding a command to periodically invoke the lambda function
2. B. Configure an environment variable named PERIOD for the Lambda functio
3. C. Set the value to 600.
4. D. Create an Amazon EventBridge rule that runs on a regular schedule to invoke the Lambda function.
5. E. Create an Amazon Simple Notification Service (Amazon SNS) topic that has a subscription to the Lambda function with a 600-second timer.

Correct Answer: C
The solution that will meet the requirements is to create an Amazon EventBridge rule that runs on a regular schedule to invoke the Lambda function. This way, the developer can use an automated and serverless way to invoke the function every 10 minutes. The developer can also use a cron expression or a rate expression to specify the schedule for the rule. The other options either involve using an Amazon EC2 instance, which is not serverless, or using environment variables or query parameters, which do not trigger the function.
Reference: Schedule AWS Lambda functions using EventBridge

A developer is creating a mobile app that calls a backend service by using an Amazon API Gateway REST API. For integration testing during the development phase, the developer wants to simulate different backend responses without invoking the backend service.
Which solution will meet these requirements with the LEAST operational overhead?

1. A. Create an AWS Lambda functio
2. B. Use API Gateway proxy integration to return constant HTTP responses.
3. C. Create an Amazon EC2 instance that serves the backend REST API by using an AWS CloudFormation template.
4. D. Customize the API Gateway stage to select a response type based on the request.
5. E. Use a request mapping template to select the mock integration response.

Correct Answer: D
Amazon API Gateway supports mock integration responses, which are predefined responses that can be returned without sending requests to a backend service. Mock integration responses can be used for testing or prototyping purposes, or for simulating different backend responses based on certain conditions. A request mapping template can be used to select a mock integration response based on an expression that evaluates some aspects of the request, such as headers, query strings, or body content. This solution does not require any additional resources or code changes and has the least operational overhead. Reference: Set up mock integrations for an API Gateway REST API
https://docs.aws.amazon.com/apigateway/latest/developerguide/how-to-mock- integration.html

A developer is building a serverless application by using AWS Serverless Application Model (AWS SAM) on multiple AWS Lambda functions. When the application is deployed, the developer wants to shift 10% of the traffic to the new deployment of the application for the first 10 minutes after deployment. If there are no issues, all traffic must switch over to the new version.
Which change to the AWS SAM template will meet these requirements?

1. A. Set the Deployment Preference Type to Canaryl OPercent10Minute
2. B. Set the AutoPublishAlias property to the Lambda alias.
3. C. Set the Deployment Preference Type to Linearl OPercentEveryIOMinute
4. D. Set AutoPubIishAIias property to the Lambda alias.
5. E. Set the Deployment Preference Type to Canaryl OPercentIOMinute
6. F. Set the PreTraffic and PostTraffic properties to the Lambda alias.
7. G. Set the Deployment Preference Type to Linearl OPercentEvery10Minute
8. H. Set PreTraffic and PostTraffic properties to the Lambda alias.

Correct Answer: A
✑ The Deployment Preference Type property specifies how traffic should be shifted between versions of a Lambda function1. The Canary10Percent10Minutes option means that 10% of the traffic is immediately shifted to the new version, and after 10 minutes, the remaining 90% of the traffic is shifted1. This matches the requirement of shifting 10% of the traffic for the first 10 minutes, and then switching all traffic to the new version.
✑ The AutoPublishAlias property enables AWS SAM to automatically create and update a Lambda alias that points to the latest version of the function1. This is required to use the Deployment Preference Type property1. The alias name can be specified by the developer, and it can be used to invoke the function with the latest code.