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Why Option A is Correct:Auto-scaling with a target utilization ensures the DynamoDB table dynamically adjusts capacity based on workload, maintaining high performance while optimizing cost. Setting a reasonable target utilization minimizes overprovisioning and throttling risks.

Why Other Options are Incorrect:

Option B:On-demand capacity is costlier than provisioned throughput for predictable workloads.

Option C:Using manual CloudWatch alarms and Lambda for scaling is less efficient and adds operational overhead.

Option D:DAX accelerates read performance but does not improve write performance.

AWS Documentation References:

DynamoDB Auto Scaling

This solution will meet the requirements by using IAM database authentication for Aurora, which enables using IAM roles or users to authenticate with Aurora databases instead of using passwords or other secrets. The developer can use IAM database authentication for Aurora to enable secure database connections for all the Lambda functions that access Aurora DB instance. The developer can create an IAM role with permission to connect to Aurora DB instance and attach it to each Lambda function. The developer can also configure Aurora DB instance to use IAM database authentication and enable encryption in transit using SSL certificates. This way, the Lambda functions can use a single securely encrypted database connection string to access Aurora without needing any secrets or passwords. Option B is not optimal because it will store the credentials and read them from an encrypted Amazon RDS DB instance, which may introduce additional costs and complexity for managing and accessing another RDS DB instance. Option C is not optimal because it will store the credentials in AWS Systems Manager Parameter Store as a secure string parameter, which may require additional steps or permissions to retrieve and decrypt the credentials from Parameter Store. Option D is not optimal because it will use Lambda environment variables with a shared AWS Key Management Service (AWS KMS) key for encryption, which may not be secure or scalable as environment variables are stored as plain text unless encrypted with AWS KMS.

Option B:Thetarget group portin the ALB must match the port specified in the ECS task definition. If there is a mismatch, the ALB health check will fail since it cannot correctly route traffic to the container.

Option E:The ALB listener must have a default action that forwards requests to the correct target group associated with the ECS service. If this configuration is missing, the health check will fail as no traffic is routed to the service.

Option Ais irrelevant to resolving health check issues since capacity providers relate to provisioning compute capacity.

Option C(hosted zone) is not directly related to ALB health checks.

Option D(redirecting traffic) is not related to ECS health check configurations.

Requirement Summary:

E-commerce app usingAmazon RDS for MySQL

Needscaching layerformost-viewed products

Evaluate Options:

A. Add a cache node to RDS

❌No such feature inRDS for MySQL

Caching must be implementedoutsideRDS

✅B. ElastiCache for Redis (OSS)

✅Purpose-built forcachingfrequently accessed data

✅Reduces read pressure on RDS

✅Fast in-memory access (microseconds)

✅Seamless integration into app logic

C. DynamoDB DAX

❌DAX is for acceleratingDynamoDB, not RDS

D. RDS standby instance

❌Read from standby is not allowed

Standby is forfailover only, not for load balancing

ElastiCache for Redis:https://docs.aws.amazon.com/AmazonElastiCache/latest/red-ug/WhatIs.html

Caching with Redis for RDS:https://aws.amazon.com/blogs/database/caching-strategies-using-amazon-elasticache-for-read-heavy-workloads-on-amazon-rds/

Requirement Summary:

Developer usesAWS IAM Identity Center (SSO)withAWS CLI / SDKs

Initially working fine

Now receiving AccessDenied errors

No changes to config or scripts

Key Understanding:

IAM Identity Center credentials aretemporary and time-limited. When you use SSO-based access via the AWS CLI (aws sso login), it obtainstemporary credentialsstored in the local cache.

By default,these expire in 1 hour(can be extended).

Evaluate Options:

A. Permissions to CLI binary changed

❌Unlikely – this would produce execution errors, not AccessDenied from AWS API

B. Permission set lacks required permissions

❌Then the error would have occurred from the beginning, not after time

✅C. IAM Identity Center credentials expired

✅Most likely– user hasn't refreshed credentials using aws sso login again

After expiration, API calls fail with AccessDenied

D. Developer is calling the wrong AWS account

❌Would likely show different types of errors (AccountNotFound, etc.)

SSO and AWS CLI:https://docs.aws.amazon.com/cli/latest/userguide/cli-configure-sso.html

Troubleshooting SSO CLI:https://docs.aws.amazon.com/cli/latest/userguide/sso-configure-profile-token.html

An SQS FIFO queue is a type of queue that preserves the order of messages and ensures that each message is delivered and processed only once1. This is suitable for the scenario where the developer wants to ensure that there are no out-of-order updates in the legacy system.

The visibility timeout value is the amount of time that a message is invisible in the queue after a consumer receives it2. This prevents other consumers from processing the same message simultaneously. If the consumer does not delete the message before the visibility timeout expires, the message becomes visible again and another consumer can receive it2.

In this scenario, the developer needs to configure the visibility timeout value to be longer than the maximum processing time of the legacy system, which is 5 minutes. This will ensure that the message remains invisible in the queue until the legacy system finishes processing it and deletes it. This will prevent duplicate or out-of-order processing of messages by the legacy system.

Containerization: Packaging the application as a container image promotes portability and standardization. Docker is the standard tool for containerization.

Amazon ECR: ECR is a managed container registry designed to work seamlessly with AWS container services.

Fargate: ECS Fargate provides serverless container orchestration, minimizing operational overhead for this proof-of-concept.

The correct answer is C. Use an AWS Lambda function that is invoked by an Amazon EventBridge scheduled event.

C. Use an AWS Lambda function that is invoked by an Amazon EventBridge scheduled event. This is correct. AWS Lambda is a serverless compute service that lets you run code without provisioning or managing servers.Lambda runs your code on a high-availability compute infrastructure and performs all of the administration of thecompute resources, including server and operating system maintenance, capacity provisioning and automatic scaling, and logging1.Amazon EventBridge is a serverlessevent bus service that enables you to connect your applications with data from a variety of sources2.EventBridge can create rules that run on a schedule, either at regular intervals or at specific times and dates, and invoke targets such as Lambdafunctions3. This solution meets the requirements of creating a small application that makes the same API call once each day at a designated time, without requiring any infrastructure in the AWS Cloud or any operational overhead.

A. Use a Kubernetes cron job that runs on Amazon Elastic Kubernetes Service (Amazon EKS). This is incorrect.Amazon EKS is a fully managed Kubernetes service that allows you to run containerized applications on AWS4.Kubernetes cron jobs are tasks that run periodically on a given schedule5. This solution could meet the functional requirements of creating a small application that makes the same API call once each day at a designated time, but it would not be the most operationally efficient manner. The company would need to provision and manage an EKS cluster, which would incur additional costs and complexity.

B. Use an Amazon Linux crontab scheduled job that runs on Amazon EC2. This is incorrect.Amazon EC2 is a web service that provides secure, resizable compute capacity in the cloud6.Crontab is a Linux utility that allows you to schedule commands orscripts to run automatically at a specified time or date7. This solution could meet the functional requirements of creating a small application that makes the same API call once each day at a designated time, but it would not be the most operationally efficient manner. The company would need to provision and manage an EC2 instance, which would incur additional costs and complexity.

D. Use an AWS Batch job that is submitted to an AWS Batch job queue. This is incorrect.AWS Batch enables you to run batch computing workloads on the AWS Cloud8.Batch jobs are units of work that can be submitted to job queues, where they are executed in parallel or sequentially on compute environments9. This solution could meet the functional requirements of creating a small application that makes the same API call once each day at a designated time, but it would not be the most operationally efficient manner. The company would need to configure and manage an AWS Batch environment, which would incur additional costs and complexity.