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A developer is designing an application that requires the client IP address for processing. After moving the application behind an Application Load Balancer (ALB), all client IP addresses appear identical. Which solution meets this requirement in the most cost‑effective manner?

• Remove the application from the ALB, delete the ALB, and use Route 53 to direct traffic directly to the instance.
• Use a Classic Load Balancer instead of an ALB.
• Modify the application code to inspect the X‑Forwarded‑For header and process the list of IP addresses.
• Modify the application code to inspect a custom header where the client sends its IP address.

A company needs to distribute firmware updates worldwide. Which service allows for easy and secure control of download access at the lowest cost?

• Use Amazon CloudFront with signed URLs for S3 content.
• Create a dedicated CloudFront distribution for each customer.
• Use CloudFront with LambdaEdge
• Use API Gateway and Lambda to control access to S3.

A company uses AWS Lambda functions triggered by S3 events to process images stored in an S3 bucket. After a production deployment, the development S3 buckets inadvertently invoke production Lambda functions, causing development files to be processed by production code. Which solution meets these requirements while following security best practices?

• Update the production Lambda function’s execution role to add a policy that allows reading only from the production S3 bucket.
• Move development and production environments into separate AWS accounts and add a resource policy to each Lambda function to allow only S3 buckets in the same account to invoke the function.
• Add a resource policy to the production Lambda function to allow only the production S3 bucket to invoke it.
• Move development and production environments into separate AWS accounts and update each Lambda function’s execution role to allow reading only from the S3 bucket in the same account.

A developer needs to launch a new EC2 instance using the AWS CLI. Which command should be used?

• aws ec2 bundle-instance.
• aws ec2 start-instances.
• aws ec2 confirm-product-instance.
• aws ec2 run-instances.

A developer wants to accelerate the deployment workflow for a serverless application so that only incremental changes are deployed without re‑deploy all the environment for each commit.

• Use AWS SAM and deploy incremental changes using the “sam sync” command.
• Use AWS SAM with the “sam init” command for incremental deployments.
• Use AWS CDK with “cdk synth” to deploy changes.
• Use AWS CDK with “cdk bootstrap” for incremental deployments.

A serverless application processes customer orders using a Lambda function that calls an external payment API, which sometimes times out. The company wants the support team to be notified via an existing SNS topic when the external API's error rate exceeds 5% of transactions in an hour. Which approach meets these requirements?

• Log payment API call results to CloudWatch and use CloudWatch Logs Insights with a scheduled Lambda function to query logs and notify SNS.
• Publish custom CloudWatch metrics for payment API failures and set up a CloudWatch alarm to alert SNS when error rates exceed 5%.
• Publish API call results to a new SNS topic and subscribe the support team to it.
• Store API call results in S3 and use scheduled Athena queries to detect high error rates and trigger SNS notifications.

A developer is building an application for IoT devices that sends data to a RESTful API (implemented via AWS Lambda) with each request assigned a unique identifier. Since request volumes can spike and duplicates may occur during throttling, the API must handle duplicate requests without inconsistencies. Which solution meets these requirements?

• Use an Amazon RDS MySQL instance to store each request's unique identifier and have the Lambda function check this database before processing.
• Use an Amazon DynamoDB table to store unique request identifiers and have the Lambda function verify the identifier before processing.
• Use an Amazon DynamoDB table to store unique identifiers and have the Lambda function return an error for duplicate requests.
• Use an Amazon ElastiCache for Memcached instance to store unique identifiers and check the cache in the Lambda function before processing.

A developer is building an application that retrieves and groups data from several public API endpoints using a Lambda function. Which deployment strategy minimizes performance impact?

• Deploy the Lambda function in a container image.
• Use a scheduled Lambda function triggered by CloudWatch Events.
• Use the AWS Lambda local invoke command with simulated events for testing.
• Implement a caching layer using AWS Lambda layers.

A developer is creating an application on EC2 that opens connections to an RDS for SQL Server database. The application must not hardcode database credentials, and the credentials must be automatically rotated. Which solution meets these requirements?

• Create an IAM role with database access and attach it to the EC2 instances.
• Store credentials in AWS Secrets Manager with automatic rotation enabled and retrieve them at runtime.
• Store credentials in an encrypted file in S3 and download them at instance launch.
• Store credentials in a DynamoDB table and use a scheduled Lambda function to update them.

A development team uses a single CloudFormation template to deploy a web application and an RDS database across various environments. After a mistaken deployment dropped and recreated the development database causing data loss, which solutions can prevent accidental deletion of the database in the future? (Choose two)

• Add a CloudFormation DeletionPolicy attribute with the Retain value to the database resource.
• Update the CloudFormation stack policy to prevent updates that could delete the database.
• Modify the database to use a Multi‑AZ deployment.
• Create a CloudFormation stack set for deploying the web application and database.
• Add a CloudFormation DeletionPolicy attribute with the Retain value to the entire stack.