- (Topic 2)
A solutions architect needs to help a company optimize the cost of running an application on AWS. The application will use Amazon EC2 instances, AWS Fargate, and AWS Lambda for compute within the architecture.
The EC2 instances will run the data ingestion layer of the application. EC2 usage will be sporadic and unpredictable. Workloads that run on EC2 instances can be interrupted at any time. The application front end will run on Fargate, and Lambda will serve the API layer. The front-end utilization and API layer utilization will be predictable over the course of the next year.
Which combination of purchasing options will provide the MOST cost-effective solution for hosting this application? (Choose two.)

1. A. Use Spot Instances for the data ingestion layer
2. B. Use On-Demand Instances for the data ingestion layer
3. C. Purchase a 1-year Compute Savings Plan for the front end and API layer.
4. D. Purchase 1-year All Upfront Reserved instances for the data ingestion layer.
5. E. Purchase a 1-year EC2 instance Savings Plan for the front end and API layer.

Correct Answer: AC
EC2 instance Savings Plan saves 72% while Compute Savings Plans saves 66%. But according to link, it says "Compute Savings Plans provide the most flexibility and help to reduce your costs by up to 66%. These plans automatically apply to EC2 instance usage regardless of instance family, size, AZ, region, OS or tenancy, and also apply to Fargate and Lambda usage." EC2 instance Savings Plans are not applied to Fargate or Lambda

- (Topic 3)
A data analytics company wants to migrate its batch processing system to AWS. The company receives thousands of small data files periodically during the day through FTP. A on-premises batch job processes the data files overnight. However, the batch job takes hours to finish running.
The company wants the AWS solution to process incoming data files are possible with minimal changes to the FTP clients that send the files. The solution must delete the incoming data files the files have been processed successfully. Processing for each file needs to take 3-8 minutes.
Which solution will meet these requirements in the MOST operationally efficient way?

1. A. Use an Amazon EC2 instance that runs an FTP server to store incoming files as objects in Amazon S3 Glacier Flexible Retrieva
2. B. Configure a job queue in AWS Batc
3. C. Use Amazon EventBridge rules to invoke the job to process the objects nightly from S3 Glacier Flexible Retrieva
4. D. Delete the objects after the job has processed the objects.
5. E. Use an Amazon EC2 instance that runs an FTP server to store incoming files on an Amazon Elastic Block Store (Amazon EBS) volum
6. F. Configure a job queue in AWS Batc
7. G. Use Amazon EventBridge rules to invoke the process the files nightly from the EBSvolum
8. H. Delete the files after the job has processed the files.
9. I. Use AWS Transfer Family to create an FTP server to store incoming files on an Amazon Elastic Block Store (Amazon EBS) volum
10. J. Configure a job queue in AWS Batc
11. K. Use an Amazon S3 event notification when each files arrives to invoke the job in AWS Batc
12. L. Delete the files after the job has processed the files.
13. M. Use AWS Transfer Family to create an FTP server to store incoming files in Amazon S3 Standar
14. N. Create an AWS Lambda function to process the files and to delete the files after they are proessed.yse an S3 event notification to invoke the lambda function when the fils arrive

Correct Answer: D
This option is the most operationally efficient because it uses AWS Transfer Family to create an FTP server that can store incoming files in Amazon S3 Standard12, which is a low-cost and highly available storage service. It also uses AWS Lambda to process the files and delete them after they are processed, which is a serverless and scalable solution that does not require any batch scheduling or infrastructure management. It also uses S3 event notifications to invoke the Lambda function when the files arrive, which enables near real-time processing of the incoming data files3. Option A is less efficient because it uses Amazon S3 Glacier Flexible Retrieval, which is a cold storage class that has higher retrieval costs and longer retrieval times than Amazon S3 Standard. It also uses EventBridge rules to invoke the job nightly, which does not meet the requirement of processing incoming data files as soon as possible. Option B is less efficient because it uses an EBS volume to store incoming files, which is a block storage service that has higher costs and lower durability than Amazon S3. It also uses EventBridge rules to invoke the job nightly, which does not meet the requirement of processing incoming data files as soon as possible. Option C is less efficient because it uses an EBS volume to store incoming files, which is a block storage service that has higher costs and lower durability than Amazon S3. It also uses AWS Batch to process the files, which requires managing compute resources and job queues.

- (Topic 4)
A development team is collaborating with another company to create an integrated product. The other company needs to access an Amazon Simple Queue Service (Amazon SQS) queue that is contained in the development team's account. The other company wants to poll the queue without giving up its own account permissions to do so.
How should a solutions architect provide access to the SQS queue?

1. A. Create an instance profile that provides the other company access to the SQS queue.
2. B. Create an 1AM policy that provides the other company access to the SQS queue.
3. C. Create an SQS access policy that provides the other company access to the SQS queue.
4. D. Create an Amazon Simple Notification Service (Amazon SNS) access policy that provides the other company access to the SQS queue.

Correct Answer: C
To provide access to the SQS queue to the other company without giving up its own account permissions, a solutions architect should create an SQS access policy that provides the other company access to the SQS queue. An SQS access policy is a resource-based policy that defines who can access the queue and what actions they can perform. The policy can specify the AWS account ID of the other company as a principal, and grant permissions for actions such as sqs:ReceiveMessage, sqs:DeleteMessage, and sqs:GetQueueAttributes. This way, the other company can poll the queue using its own credentials, without needing to assume a role or use cross-account access
keys. References:
✑ Using identity-based policies (IAM policies) for Amazon SQS
✑ Using custom policies with the Amazon SQS access policy language

- (Topic 1)
A company wants to move a multi-tiered application from on premises to the AWS Cloud to improve the application's performance. The application consists of application tiers that communicate with each other by way of RESTful services. Transactions are dropped when one tier becomes overloaded. A solutions architect must design a solution that resolves these issues and modernizes the application.
Which solution meets these requirements and is the MOST operationally efficient?

1. A. Use Amazon API Gateway and direct transactions to the AWS Lambda functions as the application laye
2. B. Use Amazon Simple Queue Service (Amazon SQS) as the communication layer between application services.
3. C. Use Amazon CloudWatch metrics to analyze the application performance history to determine the server's peak utilization during the performance failure
4. D. Increase the size of the application server's Amazon EC2 instances to meet the peak requirements.
5. E. Use Amazon Simple Notification Service (Amazon SNS) to handle the messaging between application servers running on Amazon EC2 in an Auto Scaling grou
6. F. Use Amazon CloudWatch to monitor the SNS queue length and scale up and down as required.
7. G. Use Amazon Simple Queue Service (Amazon SQS) to handle the messaging between application servers running on Amazon EC2 in an Auto Scaling grou
8. H. Use Amazon CloudWatch to monitor the SQS queue length and scale up when communication failures are detected.

Correct Answer: A
https://aws.amazon.com/getting-started/hands-on/build-serverless-web-app-lambda-apigateway-s3-dynamodb-cognito/module-4/
Build a Serverless Web Application with AWS Lambda, Amazon API Gateway, AWS Amplify, Amazon DynamoDB, and Amazon Cognito. This example showed similar setup as question: Build a Serverless Web Application with AWS Lambda, Amazon API Gateway, AWS Amplify, Amazon DynamoDB, and Amazon Cognito

- (Topic 4)
A manufacturing company has machine sensors that upload .csv files to an Amazon S3 bucket. These .csv files must be converted into images and must be made available as soon as possible for the automatic generation of graphical reports.
The images become irrelevant after 1 month, but the .csv files must be kept to train machine learning (ML) models twice a year. The ML trainings and audits are planned weeks in advance.
Which combination of steps will meet these requirements MOST cost-effectively? (Select TWO.)

1. A. Launch an Amazon EC2 Spot Instance that downloads the .csv files every hour, generates the image files, and uploads the images to the S3 bucket.
2. B. Design an AWS Lambda function that converts the .csv files into images and stores the images in the S3 bucke
3. C. Invoke the Lambda function when a .csv file is uploaded.
4. D. Create S3 Lifecycle rules for .csv files and image files in the S3 bucke
5. E. Transition the.csv files from S3 Standard to S3 Glacier 1 day after they are uploade
6. F. Expire the image files after 30 days.
7. G. Create S3 Lifecycle rules for .csv files and image files in the S3 bucke
8. H. Transition the.csv files from S3 Standard to S3 One Zone-Infrequent Access (S3 One Zone-IA) 1 day after they are uploade
9. I. Expire the image files after 30 days.
10. J. Create S3 Lifecycle rules for .csv files and image files in the S3 bucke
11. K. Transition the.csv files from S3 Standard to S3 Standard-Infrequent Access (S3 Standard-IA) 1 day after they are uploade
12. L. Keep the image files in Reduced Redundancy Storage (RRS).

Correct Answer: BC
These answers are correct because they meet the requirements of
converting the .csv files into images, making them available as soon as possible, and minimizing the storage costs. AWS Lambda is a service that lets you run code without provisioning or managing servers. You can use AWS Lambda to design a function that converts the .csv files into images and stores the images in the S3 bucket. You can invoke the Lambda function when a .csv file is uploaded to the S3 bucket by using an S3 event notification. This way, you can ensure that the images are generated and made available as soon as possible for the graphical reports. S3 Lifecycle is a feature that enables you to manage your objects so that they are stored cost effectively throughout their lifecycle. You can create S3 Lifecycle rules for .csv files and image files in the S3 bucket to transition them to different storage classes or expire them based on your business needs. You can transition the .csv files from S3 Standard to S3 Glacier 1 day after they are uploaded, since they are only needed twice a year for ML trainings and audits that are planned weeks in advance. S3 Glacier is a storage class for data archiving that offers secure, durable, and extremely low-cost storage with retrieval times ranging from minutes to hours. You can expire the image files after 30 days, since they become irrelevant after 1 month. References:
✑ https://docs.aws.amazon.com/lambda/latest/dg/welcome.html
✑ https://docs.aws.amazon.com/AmazonS3/latest/userguide/NotificationHowTo.html
✑ https://docs.aws.amazon.com/AmazonS3/latest/userguide/object-lifecycle- mgmt.html
✑ https://docs.aws.amazon.com/AmazonS3/latest/userguide/storage-class- intro.html#sc-glacier