DVA-C02 practice questions 291–300

1. Question 291 · 548 in bank

   A developer manages an application that writes customer orders to an Amazon DynamoDB table. The orders use customer_id as the partition key, order_id as the sort key, and order_date as an attribute. A new access pattern requires accessing data by order_date and order_id. The developer needs to implement a new AWS Lambda function to support the new access pattern. How should the developer support the new access pattern in the MOST operationally efficient way?

   • AAdd a new local secondary index (LSI) to the DynamoDB table that specifies order_date as the partition key and order_id as the sort key. Write the new Lambda function to query the new LSI index.
   • BWrite the new Lambda function to scan the DynamoDB table. In the Lambda function, write a method to retrieve and combine results by order_date and order_id.
   • CAdd a new global secondary index (GSI) to the DynamoDB table that specifies order_date as the partition key and order_id as the sort key. Write the new Lambda function to query the new GSI index.
   • DEnable DynamoDB Streams on the table. Choose the new and old images information to write to the DynamoDB stream. Write the new Lambda function to query the DynamoDB stream

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   Answer: C

   Explanation

   C Global Secondary Index (GSI) allows you to specify a completely different partition key and potentially a different sort key from those on the main table. This flexibility is crucial when you need to support additional access patterns that aren't directly supported by the existing table's key structure. In this scenario, specifying order_date as the new partition key and order_id as the sort key in a GSI will enable efficient querying based on these attributes. Lambda Function Querying GSI: Once the GSI is set up, the Lambda function can perform efficient query operations directly on this index to fetch records based on order_date and order_id, which is much more efficient than scanning the entire table.

   Source: Adapted from community discussion — tomchandler077

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2. Question 292 · 548 in bank

   A developer is creating a web application for a school that stores data in Amazon DynamoDB. The ExamScores table has the following attributes: student_id, subject_name, and top_score. Each item in the ExamScores table is identified with student_id as the partition key and subject_name as the sort key. The web application needs to display the student _id for the top scores for each school subject. The developer needs to increase the speed of the queries to retrieve the student_id for the top scorer for each school subject. Which solution will meet these requirements?

   • ACreate a local secondary index (LSI) with subject_name as the partition key and top_score as the sort key.
   • BCreate a local secondary index (LSI) with top_score as the partition key and student_id as the sort key.
   • CCreate a global secondary index (GSI) with subject_name as the partition key and top_score as the sort key.
   • DCreate a global secondary index (GSI) with subject_name as the partition key and student_id as the sort key.

   Show answer

   Answer: C

   Explanation

   The best solution is C. Create a global secondary index (GSI) with subject_name as the partition key and top_score as the sort key. Here's why: The goal is to efficiently retrieve the student ID of the top scorer for each subject. A GSI allows querying on a key combination different from the table's primary key. By using subject_name as the partition key, you can easily query all scores for a given subject. Then, sorting by top_score in descending order will allow you to quickly identify the top scorer using a single query. An LSI (options A and B) is tied to the table's primary key, making efficient retrieval of this data impossible. Option D would allow retrieval of student IDs given a subject, but not directly sorted by top score to find the top scorer for each subject efficiently. A GSI offers the flexibility to achieve the desired retrieval speeds without requiring multiple queries.

   Source: Adapted from community discussion — examuserss

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3. Question 293 · 548 in bank

   A developer wrote an application that uses an AWS Lambda function to asynchronously generate short videos based on requests from customers. This video generation can take up to 10 minutes. After the video is generated, a URL to download the video is pushed to the customer's web browser. The customer should be able to access these videos for at least 3 hours after generation. Which solution will meet these requirements?

   • AStore the video in the /tmp folder within the Lambda execution environment. Push a Lambda function URL to the customer.
   • BStore the video in an Amazon Elastic File System (Amazon EFS) file system attached to the function. Generate a pre-signed URL for the video object and push the URL to the customer.
   • CStore the video in Amazon S3. Generate a pre-signed URL for the video object and push the URL to the customer.
   • DStore the video in an Amazon CloudFront distribution. Generate a pre-signed URL for the video object and push the URL to the customer.

   Show answer

   Answer: C

   Explanation

   By default, all Amazon S3 objects are private, only the object owner has permission to access them. However, the object owner may share objects with others by creating a presigned URL. A presigned URL uses security credentials to grant time-limited permission to download objects. The URL can be entered in a browser or used by a program to download the object. The credentials used by the presigned URL are those of the AWS user who generated the URL.

   Source: Adapted from community discussion — preachr

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4. Question 294 · 548 in bank

   A developer is creating an AWS Lambda function that is invoked by messages to an Amazon Simple Notification Service (Amazon SNS) topic. The messages represent customer data updates from a customer relationship management (CRM) system The developer wants the Lambda function to process only the messages that pertain to email address changes. Additional subscribers to the SNS topic will process any other messages. Which solution will meet these requirements in the LEAST development effort?

   • AUse Lambda event filtering to allow only messages that are related to email address changes to invoke the Lambda function.
   • BUse an SNS filter policy on the Lambda function subscription to allow only messages that are related to email address changes to invoke the Lambda function.
   • CSubscribe an Amazon Simple Queue Service (Amazon SQS) queue to the SNS topic. Configure the SQS queue with a filter policy to allow only messages that are related to email address changes. Connect the SQS queue to the Lambda function.
   • DConfigure the Lambda code to check the received message. If the message is not related to an email address change, configure the Lambda function to publish the message back to the SNS topic for the other subscribers to process.

   Show answer

   Answer: B

   Explanation

   SNS filter policies are designed specifically for this purpose and require the least development effort. They allow you to filter messages at the SNS level before they reach the Lambda function.

   Source: Adapted from community discussion — KennethNg923

   References

   • AWS documentation
   • AWS documentation

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5. Question 295 · 548 in bank

   A developer is designing a fault-tolerant environment where client sessions will be saved. How can the developer ensure that no sessions are lost if an Amazon EC2 instance fails?

   • AUse sticky sessions with an Elastic Load Balancer target group.
   • BUse Amazon SQS to save session data.
   • CUse Amazon DynamoDB to perform scalable session handling.
   • DUse Elastic Load Balancer connection draining to stop sending requests to failing instances.

   Show answer

   Answer: C

   Explanation

   Sticky sessions ensure that all requests from a particular client are sent to the same EC2 instance. While this can be useful for maintaining session state, it doesn't protect against data loss if an instance fails. If the instance holding a client's session fails, that session data would be lost. C is Correct: Use Amazon DynamoDB to perform scalable session handling. If an EC2 instance fails, the session data stored in DynamoDB remains intact and can be accessed by other instances.

   Source: Adapted from community discussion — KennethNg923

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6. Question 296 · 548 in bank

   A developer is creating AWS CloudFormation templates to manage an application's deployment in Amazon Elastic Container Service (Amazon ECS) through AWS CodeDeploy. The developer wants to automatically deploy new versions of the application to a percentage of users before the new version becomes available for all users. How should the developer manage the deployment of the new version?

   • AModify the CloudFormation template to include a Transform section and the AWS::CodeDeploy::BlueGreen hook.
   • BDeploy the new version in a new CloudFormation stack. After testing is complete, update the application's DNS records for the new stack.
   • CRun CloudFormation stack updates on the application stack to deploy new application versions when they are available.
   • DCreate a nested stack for the new version. Include a Transform section and the AWS::CodeDeploy::BlueGreen hook.

   Show answer

   Answer: A

   Explanation

   option A leverages the AWS::CodeDeploy::BlueGreen transform hook in the CloudFormation template. This hook allows the developer to specify blue/green deployment strategies directly in the CloudFormation template. It facilitates deploying new versions to a subset of users (canary or linear deployments) before fully rolling out to all users. This approach is designed for seamless and automated deployments using AWS CodeDeploy and ECS.

   Source: Adapted from community discussion — rdiaz

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7. Question 297 · 548 in bank

   Select 2

   A developer has written a distributed application that uses microservices. The microservices are running on Amazon EC2 instances. Because of message volume, the developer is unable to match log output from each microservice to a specific transaction. The developer needs to analyze the message flow to debug the application. Which combination of steps should the developer take to meet this requirement? (Choose two.)

   • ADownload the AWS X-Ray daemon. Install the daemon on an EC2 instance. Ensure that the EC2 instance allows UDP traffic on port 2000.
   • BConfigure an interface VPC endpoint to allow traffic to reach the global AWS X-Ray daemon on TCP port 2000.
   • CEnable AWS X-Ray. Configure Amazon CloudWatch to push logs to X-Ray.
   • DAdd the AWS X-Ray software development kit (SDK) to the microservices. Use X-Ray to trace requests that each microservice makes.
   • ESet up Amazon CloudWatch metric streams to collect streaming data from the microservices.

   Show answer

   Answer: AD

   Explanation

   A. The X-Ray daemon is necessary for collecting trace data from the EC2 instances running the microservices. It needs to be installed on each EC2 instance, and UDP port 2000 should be open for the daemon to communicate with the X-Ray service. D. Adding the X-Ray SDK to the microservices allows you to instrument your application code to send trace data to X-Ray. This is crucial for tracing requests across different microservices.

   Source: Adapted from community discussion — KennethNg923

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8. Question 298 · 548 in bank

   A company is working on a new serverless application. A developer needs to find an automated way to deploy AWS Lambda functions and the dependent infrastructure with minimum coding effort. The application also needs to be reliable. Which method will meet these requirements with the LEAST operational overhead?

   • ABuild the application by using shell scripts to create .zip files for each Lambda function. Manually upload the .zip files to the AWS Management Console.
   • BBuild the application by using the AWS Serverless Application Model (AWS SAM). Use a continuous integration and continuous delivery (CI/CD) pipeline and the SAM CLI to deploy the Lambda functions.
   • CBuild the application by using shell scripts to create .zip files for each Lambda function. Upload the .zip files. Deploy the .zip files as Lambda functions by using the AWS CLI in a continuous integration and continuous delivery (CI/CD) pipeline.
   • DBuild a container for each Lambda function. Store the container images in AWS CodeArtifact. Deploy the containers as Lambda functions by using the AWS CLI in a continuous integration and continuous delivery (CI/CD) pipeline.

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   Answer: B

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9. Question 299 · 548 in bank

   A company has an Amazon S3 bucket that contains sensitive data. The data must be encrypted in transit and at rest. The company encrypts the data in the S3 bucket by using an AWS Key Management Service (AWS KMS) key. A developer needs to grant several other AWS accounts the permission to use the S3 GetObject operation to retrieve the data from the S3 bucket. How can the developer enforce that all requests to retrieve the data provide encryption in transit?

   • ADefine a resource-based policy on the S3 bucket to deny access when a request meets the condition “aws:SecureTransport”: “false”.
   • BDefine a resource-based policy on the S3 bucket to allow access when a request meets the condition “aws:SecureTransport”: “false”.
   • CDefine a role-based policy on the other accounts' roles to deny access when a request meets the condition of “aws:SecureTransport”: “false”.
   • DDefine a resource-based policy on the KMS key to deny access when a request meets the condition of “aws:SecureTransport”: “false”.

   Show answer

   Answer: A

   Explanation

   A) Correct - The condition “aws:SecureTransport”: “false” ensures that only secure requests (encrypted in transit) are allowed. B) Eliminated - This allows access only when the request does not use secure transport. This is opposite of the requirement C) Eliminated - Resource-based policies at the bucket level are better suited for cross-account access. D) Eliminated - The GetObject operation is specific to the S3 bucket, not the KMS key.

   Source: Adapted from community discussion — sumanshu

   References

   • repost.aws documentation

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10. Question 300 · 548 in bank

    A developer needs to modify an application architecture to meet new functional requirements. Application data is stored in Amazon DynamoDB and processed for analysis in a nightly batch. The system analysts do not want to wait until the next day to view the processed data and have asked to have it available in near-real time. Which application architecture pattern would enable the data to be processed as it is received?

    • AEvent driven
    • BClient-server driven
    • CFan-out driven
    • DSchedule driven

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    Answer: A

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DVA-C02 practice, question 291. 548 questions available.