Question 1

A developer is deploying a company's application to Amazon EC2 instances The application generates gigabytes of data files each day The files are rarely accessed but the files must be available to the application's users within minutes of a request during the first year of storage The company must retain 7 years.

How can the developer implement the application to meet these requirements MOST cost- effectively?

A. Store the files in an Amazon S3 bucket Use the S3 Glacier Instant Retrieval storage class Create an S3 Lifecycle policy to transition the files to th Deep Archive storage class after 1 year

Accepted Answer

Amazon S3 Glacier Instant Retrieval is an archive storage class that delivers the lowest-cost storage for long-lived data that is rarely accessed and r retrieval in milliseconds. With S3 Glacier Instant Retrieval, you can save up to 68% on storage costs compared to using the S3 Standard-

Infrequent Access (S3 Standard-IA) storage class, when your data is accessed once per quarter. https://aws.amazon.com/s3/storage- classes/glacier/instan retrieval/

Question 2

A development team wants to build a continuous integration/continuous delivery (CI/CD) pipeline. The team is using AWS CodePipeline to automate the code and deployment. The team wants to store the program code to prepare for the CI/CD pipeline.

Which AWS service should the team use to store the program code?

Accepted Answer

AWS CodeCommit is a service that provides fully managed source control for hosting secure and scalable private Git repositories. The development team c CodeCommit to store the program code and prepare for the CI/CD pipeline. CodeCommit integrates with other AWS services such as CodePipeline, CodeBuild, and CodeDeploy to automate the code build and deployment process.

## References:

- ? [What Is AWS CodeCommit? - AWS CodeCommit]
- ? [AWS CodePipeline - AWS CodeCommit]

Question 3

A company runs an application on AWS The application uses an AWS Lambda function that is configured with an Amazon Simple Queue Service (Amazon SQS) queue called high priority queue as the event source A developer is updating the Lambda function with another SQS queue called low priority queue as the source The Lambda function must always read up to 10 simultaneous messages from the high priority queue before processing messages from low priority que The Lambda function must be limited to 100 simultaneous invocations.

Which solution will meet these requirements'?

Accepted Answer

Setting the event source mapping maximum concurrency is the best way to control how many messages from each queue are processed by the Lambda function processed concurrently from the same event at a time. The maximum concurrency setting limits the number of batches that can be source. By setting it to 10 for the high priority queue and to 90 for the low priority queue, the developer can ensure that the Lambda function always r simultaneous messages from the high priority queue before processing messages from the low priority queue, and that the total number of concurrent invoc does not exceed 100. The other solutions are either not effective or not relevant. The batch size setting controls how many messages are sent to the Lam function in a single invocation, not how many invocations are allowed at a time. The delivery delay setting controls how long a message is invisible in after it is sent, not how often it is processed by the Lambda function. The batch window setting controls how long the event source mapping can buffer m before sending a batch, not how many batches are processed concurrently. References

- ? Using AWS Lambda with Amazon SQS
- ? AWS Lambda Event Source Mapping - Examples and best practices | Shisho Dojo
- ? Lambda event source mappings - AWS Lambda
- ? aws\_lambda\_event\_source\_mapping - Terraform Registry

Question 4

A mobile app stores blog posts in an Amazon DynacnoDB table Millions of posts are added every day and each post represents a single item in the table. T mobile app requires only recent posts. Any post that is older than 48 hours can be removed.

What is the MOST cost-effective way to delete posts that are older man 48 hours?

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Accepted Answer

This solution will meet the requirements by using the Time to Live (TTL) feature of DynamoDB, which enables automatically deleting items from a table a certain time period. The developer can add a new attribute of type Number that has a timestamp that is set to 48 hours after the blog post creation time represents the expiration time of the item. The developer can configure the DynamoDB table with a TTL that references the new attribute, which instructs DynamoDB to delete the item when the current time is greater than or equal to the expiration time. This solution is also cost- effective as it does not not optimal because it will create a script to find and remove old posts with

additional charges for deleting expired items. Option A is table scan and a batch write item API operation, which may consume more read and write capacity units and incur more costs. Option B is not optimal beca will use Amazon Elastic Container Service (Amazon ECS) and AWS Fargate to run the script, which may introduce additional costs and complexity for managi and scaling containers. Option C is not optimal because it will create a global secondary index (GSI) that uses the expiration time as a sort key, which consume more storage space and incur more costs.

References: Time To Live, Managing DynamoDB Time To Live (TTL)

Question 5

A developer at a company recently created a serverless application to process and show data from business reports. The application's user interface (UI) users to select and start processing the files. The Ul displays a message when the result is available to view. The application uses AWS Step Functions Lambda functions to process the files. The developer used Amazon API Gateway and Lambda functions to create an API to support the UI.

The company's Ul team reports that the request to process a file is often returning timeout errors because of the see or complexity of the files. The Ul the API to provide an immediate response so that the Ul can deploy a message while the files are being processed. The backend process that is invoked by API needs to send an email message when the report processing is complete.

What should the developer do to configure the API to meet these requirements?

Accepted Answer

This solution allows the API to invoke the Lambda function asynchronously, which means that the API will return an immediate response without waiting f function to complete. The X-Amz-Invocation-Type header specifies the invocation type of the Lambda function, and setting it to 'Event' means that the fu will be invoked asynchronously. The function can then use Amazon Simple Email Service (SES) to send an email message when the report processing is complete.

Reference: [Asynchronous invocation], [Set up Lambda proxy integrations in API Gateway]

Question 6

An Amazon Kinesis Data Firehose delivery stream is receiving customer data that contains personally identifiable information. A developer needs to remov pattern-based customer identifiers from the data and store the modified data in an Amazon S3 bucket.

What should the developer do to meet these requirements?

Accepted Answer

Amazon Kinesis Data Firehose is a service that delivers real-time streaming data to destinations such as Amazon S3, Amazon Redshift, Amazon OpenSearch

Service, and Amazon Kinesis Data Analytics. The developer can implement Kinesis Data Firehose data transformation as an AWS Lambda function. The functio can remove pattern-based customer identifiers from the data and return the modified data to Kinesis Data Firehose. The developer can set an Amazon S3 bu as the destination of the delivery stream. References:

- ? [What Is Amazon Kinesis Data Firehose? - Amazon Kinesis Data Firehose]
- ? [Data Transformation - Amazon Kinesis Data Firehose]

Question 7

An application that runs on AWS receives messages from an Amazon Simple Queue Service (Amazon SQS) queue and processes the messages in batches. The application sends the data to another SQS queue to be consumed by another legacy application. The legacy system can take up to 5 minutes to process some transaction data.

A developer wants to ensure that there are no out-of-order updates in the legacy system. The developer cannot alter the behavior of the legacy system. Which solution will meet these requirements?

Accepted Answer

? 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 consume processing the same message simultaneously. If the consumer does not delete the message before the visibility timeout expires, the message becomes visib 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, wh minutes. This will ensure that the message remains invisible in the queue until the legacy system finishes processing it and deletes it. This will preve out-of-order processing of messages by the legacy system.

Question 8

A company runs a payment application on Amazon EC2 instances behind an Application Load Balance The EC2 instances run in an Auto Scaling group across multiple Availability Zones The application needs to retrieve application secrets during the application startup environment variables These secrets must be encrypted at rest and need to be rotated every month.

Which solution will meet these requirements with the LEAST development effort?

Accepted Answer

AWS Secrets Manager is a service that enables the secure management and rotation of secrets, such as database credentials, API keys, or passwords. By u Secrets Manager, the company can avoid hardcoding secrets in the application code or properties files, and instead retrieve them programmatically during application startup. Secrets Manager also supports automatic rotation of secrets by using AWS Lambda functions or built-in rotation templates. The compa provision a customer master key (CMK) to encrypt the secrets and use the AWS SDK or CLI to export the secrets as environment variables. References:

- ? What Is AWS Secrets Manager? - AWS Secrets Manager
- ? Rotating Your AWS Secrets Manager Secrets - AWS Secrets Manager
- ? Retrieving a Secret - AWS Secrets Manager

Question 9

A developer is creating an AWS Lambda function that searches for Items from an Amazon DynamoDQ table that contains customer contact information. The DynamoDB table items have the customers as the partition and additional properties such as customer -type, name, and job\_title.

The Lambda function runs whenever a user types a new character into the customer\_type text Input. The developer wants to search to return partial matche tne email\_address property of a particular customer type. The developer does not want to recreate the DynamoDB table. What should the developer do to meet these requirements?

Accepted Answer

The solution that will meet the requirements is to add a global secondary index (GSI) to the DynamoDB table with customer\_type as the partition key and email\_address as the sort key. Perform a query operation on the GSI by using the begins\_with key condition expression with the email\_address property. T way, the developer can search for partial matches of the email\_address property of a particular customer type without recreating the DynamoDB table. The options either involve using a local secondary index (LSI), which requires recreating the table, or using a different partition key, which does not allo customer\_type.

Reference: Using Global Secondary Indexes in DynamoDB

Question 10

A developer is creating a mobile application that will not require users to log in. What is the MOST efficient method to grant u access to AWS resources'?

Accepted Answer

This solution is the most efficient method to grant users access to AWS resources without requiring them to log in. Amazon Cognito is a service that pr sign-up, sign-in, and access control for web and mobile applications. Amazon Cognito identity pools support both authenticated and unauthenticated users Unauthenticated users receive access to your AWS resources even if they aren't logged in with any of your identity providers (IdPs). You can use Amazon Cognito to associate unauthenticated users with an IAM role that has limited access to resources, such as Amazon S3 buckets or DynamoDB tables. This deg of access is useful to display content to users before they log in or to allow them to perform certain actions without signing up. Using an identity pro securely authenticate with the application will require users to log in, which does not meet the requirement. Creating an AWS Lambda function to create user when a user accesses the application will incur unnecessary costs and complexity, and may pose security risks if not implemented properly. Creating credentials using AWS KMS and applying them to users when using the application will also incur unnecessary costs and complexity, and may not provide fi grained access control for resources.

Reference: Switching unauthenticated users to authenticated users (identity pools), Allow user access to your API without authentication (Anonymous user access)