DVA-C02 practice questions 171–180

1. Question 171 · 548 in bank

   A developer is creating a machine learning (ML) pipeline in AWS Step Functions that contains AWS Lambda functions. The developer has configured an Amazon Simple Queue Service (Amazon SQS) queue to deliver ML model parameters to the ML pipeline to train ML models. The developer uploads the trained models are uploaded to an Amazon S3 bucket. The developer needs a solution that can locally test the ML pipeline without making service integration calls to Amazon SQS and Amazon S3. Which solution will meet these requirements?

   • AUse the Amazon CodeGuru Profiler to analyze the Lambda functions used in the AWS Step Functions pipeline.
   • BUse the AWS Step Functions Local Docker Image to run and locally test the Lambda functions.
   • CUse the AWS Serverless Application Model (AWS SAM) CLI to run and locally test the Lambda functions.
   • DUse AWS Step Functions Local with mocked service integrations.

   Show answer

   Answer: D

   Explanation

   AWS Step Functions Local allows developers to test Step Functions workflows on their local machines, without the need to deploy them to AWS. By using Step Functions Local, developers can simulate Step Functions and mock the integration with AWS services such as Amazon SQS and Amazon S3. This approach is ideal for testing the flow of the ML pipeline, including the interaction of Lambda functions, without actually triggering external AWS services.

   Source: Adapted from community discussion — SerialiDr

   References

   • AWS documentation

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2. Question 172 · 548 in bank

   A company runs a batch processing application by using AWS Lambda functions and Amazon API Gateway APIs with deployment stages for development, user acceptance testing, and production. A development team needs to configure the APIs in the deployment stages to connect to third-party service endpoints. Which solution will meet this requirement?

   • AStore the third-party service endpoints in Lambda layers that correspond to the stage.
   • BStore the third-party service endpoints in API Gateway stage variables that correspond to the stage.
   • CEncode the third-party service endpoints as query parameters in the API Gateway request URL.
   • DStore the third-party service endpoint for each environment in AWS AppConfig.

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   Answer: B

   References

   • AWS documentation

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3. Question 173 · 548 in bank

   A developer is building a serverless application that runs on AWS. The developer wants to create an accelerated development workflow that deploys incremental changes to AWS for testing. The developer wants to deploy the incremental changes but does not want to fully deploy the entire application to AWS for every code commit. What should the developer do to meet these requirements?

   • AUse the AWS Serverless Application Model (AWS SAM) to build the application. Use the sam sync command to deploy the incremental changes.
   • BUse the AWS Serverless Application Model (AWS SAM) to build the application. Use the sam init command to deploy the incremental changes.
   • CUse the AWS Cloud Development Kit (AWS CDK) to build the application. Use the cdk synth command to deploy the incremental changes.
   • DUse the AWS Cloud Development Kit (AWS CDK) to build the application. Use the cdk bootstrap command to deploy the incremental changes.

   Show answer

   Answer: A

   Explanation

   Here the answer is A - sam sync. According to my research: - cdk synth: only constructs your CloudFormation template. It does not deploy (create actual resources) it to AWS. You can take the template constructed, deploy it manually in CFN console, edit or inspect. - sam init: used to initialize a new serverless application - cdk bootstrap: the main purpose of cdk bootstrap is to provision a set of resources required to support the deployment of AWS CDK applications

   Source: Adapted from community discussion — tgv

   References

   • AWS documentation

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4. Question 174 · 548 in bank

   A developer is building an application that will use an Amazon API Gateway API with an AWS Lambda backend. The team that will develop the frontend requires immediate access to the API endpoints to build the UI. To prepare the backend application for integration, the developer needs to set up endpoints. The endpoints need to return predefined HTTP status codes and JSON responses for the frontend team. The developer creates a method for an API resource. Which solution will meet these requirements?

   • ASet the integration type to AWS_PROXY. Provision Lambda functions to return hardcoded JSON data.
   • BSet the integration type to MOCK. Configure the method's integration request and integration response to associate a JSON responses with specific HTTP status codes.
   • CSet the integration type to HTTP_PROXY. Configure API Gateway to pass all requests to an external placeholder API. which the team will build.
   • DSet the integration type to MOCK. Use a method request to define HTTP status codes. Use an integration request to define JSON responses.

   Show answer

   Answer: B

   References

   • AWS documentation

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5. Question 175 · 548 in bank

   A developer is migrating an application to Amazon Elastic Kubernetes Service (Amazon EKS). The developer migrates the application to Amazon Elastic Container Registry (Amazon ECR) with an EKS cluster. As part of the application migration to a new backend, the developer creates a new AWS account. The developer makes configuration changes to the application to point the application to the new AWS account and to use new backend resources. The developer successfully tests the changes within the application by deploying the pipeline. The Docker image build and the pipeline deployment are successful, but the application is still connecting to the old backend. The developer finds that the application's configuration is still referencing the original EKS cluster and not referencing the new backend resources. Which reason can explain why the application is not connecting to the new resources?

   • AThe developer did not successfully create the new AWS account.
   • BThe developer added a new tag to the Docker image.
   • CThe developer did not update the Docker image tag to a new version.
   • DThe developer pushed the changes to a new Docker image tag.

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   Answer: C

   References

   • AWS documentation

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6. Question 176 · 548 in bank

   A developer is creating an application that reads and writes to multiple Amazon S3 buckets. The application will be deployed to an Amazon EC2 instance. The developer wants to make secure API requests from the EC2 instances without the need to manage the security credentials for the application. The developer needs to apply the principle of least privilege. Which solution will meet these requirements?

   • ACreate an IAM user. Create access keys and secret keys for the user. Associate the user with an IAM policy that allows s3:* permissions.
   • BAssociate the EC2 instance with an IAM role that has an IAM policy that allows s3:ListBucket and s3:*Object permissions for specific S3 buckets.
   • CAssociate the EC2 instance with an IAM role that has an AmazonS3FullAccess AWS managed policy.
   • DCreate a bucket policy on the S3 bucket that allows s3:ListBucket and s3:*Object permissions to the EC2 instance.

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   Answer: B

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7. Question 177 · 548 in bank

   A developer is creating an application that will be deployed on IoT devices. The application will send data to a RESTful API that is deployed as an AWS Lambda function. The application will assign each API request a unique identifier. The volume of API requests from the application can randomly increase at any given time of day. During periods of request throttling, the application might need to retry requests. The API must be able to handle duplicate requests without inconsistencies or data loss. Which solution will meet these requirements?

   • ACreate an Amazon RDS for MySQL DB instance. Store the unique identifier for each request in a database table. Modify the Lambda function to check the table for the identifier before processing the request.
   • BCreate an Amazon DynamoDB table. Store the unique identifier for each request in the table. Modify the Lambda function to check the table for the identifier before processing the request.
   • CCreate an Amazon DynamoDB table. Store the unique identifier for each request in the table. Modify the Lambda function to return a client error response when the function receives a duplicate request.
   • DCreate an Amazon ElastiCache for Memcached instance. Store the unique identifier for each request in the cache. Modify the Lambda function to check the cache for the identifier before processing the request.

   Show answer

   Answer: B

   Explanation

   I originally thought ElastiCache would provide the sufficient session management of the unique identifiers with the least latency. But apparently, the scope of this question revolves around durability, not latency. Hence, a persistent storage is better suited. And while RDS is a viable solution for durability and performance, the question specifies IoT devices which typically produce unstructured data that is better handled by No-SQL services like DynamoDB.

   Source: Adapted from community discussion — Devon_Fazekas

   References

   • repost.aws documentation
   • AWS documentation

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8. Question 178 · 548 in bank

   A developer is writing an application that will retrieve sensitive data from a third-party system. The application will format the data into a PDF file. The PDF file could be more than 1 MB. The application will encrypt the data to disk by using AWS Key Management Service (AWS KMS). The application will decrypt the file when a user requests to download it. The retrieval and formatting portions of the application are complete. The developer needs to use the GenerateDataKey API to encrypt the PDF file so that the PDF file can be decrypted later. The developer needs to use an AWS KMS symmetric customer managed key for encryption. Which solutions will meet these requirements?

   • AWrite the encrypted key from the GenerateDataKey API to disk for later use. Use the plaintext key from the GenerateDataKey API and a symmetric encryption algorithm to encrypt the file.
   • BWrite the plain text key from the GenerateDataKey API to disk for later use. Use the encrypted key from the GenerateDataKey API and a symmetric encryption algorithm to encrypt the file.
   • CWrite the encrypted key from the GenerateDataKey API to disk for later use. Use the plaintext key from the GenerateDataKey API to encrypt the file by using the KMS Encrypt API.
   • DWrite the plain text key from the GenerateDataKey API to disk for later use. Use the encrypted key from the GenerateDataKey API to encrypt the file by using the KMS Encrypt API.

   Show answer

   Answer: A

   Explanation

   Using the KMS Encrypt API to encrypt large amounts of data, such as a PDF file that could be more than 1 MB, is not efficient and can be costly. AWS KMS is designed for encrypting small amounts of data, such as encryption keys or short strings. For larger data, it's recommended to use a client-side encryption library with a data key generated by KMS.

   Source: Adapted from community discussion — CrescentShared

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9. Question 179 · 548 in bank

   A company runs an application on Amazon EC2 instances. The EC2 instances open connections to an Amazon RDS for SQL Server database. A developer needs to store and access the credentials and wants to automatically rotate the credentials. The developer does not want to store the credentials for the database in the code. Which solution will meet these requirements in the MOST secure way?

   • ACreate an IAM role that has permissions to access the database. Attach the IAM role to the EC2 instances.
   • BStore the credentials as secrets in AWS Secrets Manager. Create an AWS Lambda function to update the secrets and the database. Retrieve the credentials from Secrets Manager as needed.
   • CStore the credentials in an encrypted text file in an Amazon S3 bucket. Configure the EC2 instance launch template to download the credentials from Amazon S3 as the instance launches. Create an AWS Lambda function to update the secrets and the database.
   • DStore the credentials in an Amazon DynamoDB table. Configure an Amazon CloudWatch Events rule to invoke an AWS Lambda function to periodically update the secrets and database.

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   Answer: B

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10. Question 180 · 548 in bank

    A company wants to test its web application more frequently. The company deploys the application by using a separate AWS CloudFormation stack for each environment. The company deploys the same CloudFormation template to each stack as the application progresses through the development lifecycle. A developer needs to build in notifications for the quality assurance (QA) team. The developer wants the notifications to occur for new deployments in the final preproduction environment. Which solution will meet these requirements?

    • ACreate an Amazon Simple Notification Service (Amazon SNS) topic. Subscribe the QA team to the Amazon SNS topic. Update the CloudFormation stack options to point to the SNS topic in the pre-production environment.
    • BCreate an AWS Lambda function that notifies the QA team. Create an Amazon EventBridge rule to invoke the Lambda function on the default event bus. Filter the events on the CloudFormation service and on the CloudFormation stack Amazon Resource Name (ARN).
    • CCreate an Amazon CloudWatch alarm that monitors the metrics from CloudFormation. Filter the metrics on the stack name and the stack status. Configure the CloudWatch alarm to notify the QA team.
    • DCreate an AWS Lambda function that notifies the QA team. Configure the event source mapping to receive events from CloudFormation. Specify the filtering values to limit invocations to the desired CloudFormation stack.

    Show answer

    Answer: A

    Explanation

    A. This option involves creating an SNS topic to which the QA team subscribes. CloudFormation can indeed integrate with SNS to send notifications about stack events, making this a viable way to notify the QA team of deployment updates specifically in the pre-production environment if the CloudFormation stack in that environment is configured to publish events to this SNS topic. Based on these considerations, options A and B are the most directly relevant and practical solutions for the given requirements, with option A (SNS topic for direct CloudFormation notifications) being the most straightforward to implement for notifying the QA team of new deployments in the pre-production environment, and option B (Lambda and EventBridge) offering a more customizable solution that can filter and handle notifications based on specific criteria related to CloudFormation events.

    Source: Adapted from community discussion — SerialiDr

    References

    • AWS documentation

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DVA-C02 practice, question 171. 548 questions available.