DVA-C02 practice questions 61–70

1. Question 61 · 548 in bank

   A developer maintains applications that store several secrets in AWS Secrets Manager. The applications use secrets that have changed over time. The developer needs to identify required secrets that are still in use. The developer does not want to cause any application downtime. What should the developer do to meet these requirements?

   • AConfigure an AWS CloudTrail log file delivery to an Amazon S3 bucket. Create an Amazon CloudWatch alarm for the GetSecretValue Secrets Manager API operation requests.
   • BCreate a secretsmanager-secret-unused AWS Config managed rule. Create an Amazon EventBridge rule to initiate notifications when the AWS Config managed rule is met.
   • CDeactivate the applications secrets and monitor the applications error logs temporarily.
   • DConfigure AWS X-Ray for the applications. Create a sampling rule to match the GetSecretValue Secrets Manager API operation requests.

   Show answer

   Answer: B

   Explanation

   I think B is correct https://docs.aws.amazon.com/config/latest/developerguide/secretsmanager-secret-unused.html A. could work but requires additional work to identify unused secrets. C. is too risky and could cause downtime. D. not the right use case

   Source: Adapted from community discussion — chris_777

   References

   • AWS documentation

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2. Question 62 · 548 in bank

   A developer is writing a serverless application that requires an AWS Lambda function to be invoked every 10 minutes. What is an automated and serverless way to invoke the function?

   • ADeploy an Amazon EC2 instance based on Linux, and edit its /etc/crontab file by adding a command to periodically invoke the Lambda function.
   • BConfigure an environment variable named PERIOD for the Lambda function. Set the value to 600.
   • CCreate an Amazon EventBridge rule that runs on a regular schedule to invoke the Lambda function.
   • DCreate an Amazon Simple Notification Service (Amazon SNS) topic that has a subscription to the Lambda function with a 600-second timer.

   Show answer

   Answer: C

   Explanation

   C. Create an Amazon EventBridge rule that runs on a regular schedule to invoke the Lambda function: This is the correct and most suitable option. Amazon EventBridge (formerly CloudWatch Events) allows you to set up rules that trigger on a schedule. You can create a rule with a cron or rate expression to invoke the Lambda function every 10 minutes. This approach is fully serverless and does not require managing any servers or additional infrastructure.

   Source: Adapted from community discussion — SerialiDr

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3. Question 63 · 548 in bank

   A company is using Amazon OpenSearch Service to implement an audit monitoring system. A developer needs to create an AWS CloudFormation custom resource that is associated with an AWS Lambda function to configure the OpenSearch Service domain. The Lambda function must access the OpenSearch Service domain by using OpenSearch Service internal master user credentials. What is the MOST secure way to pass these credentials to the Lambda function?

   • AUse a CloudFormation parameter to pass the master user credentials at deployment to the OpenSearch Service domain’s MasterUserOptions and the Lambda function’s environment variable. Set the NoEcho attribute to true.
   • BUse a CloudFormation parameter to pass the master user credentials at deployment to the OpenSearch Service domain’s MasterUserOptions and to create a parameter in AWS Systems Manager Parameter Store. Set the NoEcho attribute to true. Create an IAM role that has the ssm:GetParameter permission. Assign the role to the Lambda function. Store the parameter name as the Lambda function’s environment variable. Resolve the parameter’s value at runtime.
   • CUse a CloudFormation parameter to pass the master user credentials at deployment to the OpenSearch Service domain’s MasterUserOptions and the Lambda function’s environment variable. Encrypt the parameter’s value by using the AWS Key Management Service (AWS KMS) encrypt command.
   • DUse CloudFormation to create an AWS Secrets Manager secret. Use a CloudFormation dynamic reference to retrieve the secret’s value for the OpenSearch Service domain’s MasterUserOptions. Create an IAM role that has the secretsmanager:GetSecretValue permission. Assign the role to the Lambda function. Store the secret’s name as the Lambda function’s environment variable. Resolve the secret’s value at runtime.

   Show answer

   Answer: D

   Explanation

   This approach is the most secure and aligns with best practices for managing secrets. The credentials are stored in AWS Secrets Manager, which is specifically designed for managing and protecting secrets. The credentials are retrieved dynamically at runtime by the Lambda function, and the use of IAM roles ensures that only the Lambda function has access to these secrets. This method also benefits from the security and rotation features of AWS Secrets Manager.

   Source: Adapted from community discussion — SerialiDr

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4. Question 64 · 548 in bank

   An application runs on multiple EC2 instances behind an ELB. Where is the session data best written so that it can be served reliably across multiple requests?

   • AWrite data to Amazon ElastiCache.
   • BWrite data to Amazon Elastic Block Store.
   • CWrite data to Amazon EC2 Instance Store.
   • DWrite data to the root filesystem.

   Show answer

   Answer: A

   Explanation

   The correct answer is (A). Amazon ElastiCache is a distributed memory caching solution that is ideal for session data. ElastiCache provides high-performance and durable session data storage that can be shared across multiple EC2 instances.

   Source: Adapted from community discussion — Digo30sp

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5. Question 65 · 548 in bank

   An ecommerce application is running behind an Application Load Balancer. A developer observes some unexpected load on the application during non-peak hours. The developer wants to analyze patterns for the client IP addresses that use the application. Which HTTP header should the developer use for this analysis?

   • AThe X-Forwarded-Proto header
   • BThe X-Forwarded-Host header
   • CThe X-Forwarded-For header
   • DThe X-Forwarded-Port header

   Show answer

   Answer: C

   Explanation

   C is correct. X-Forwarded-Proto: protocol (HTTP/HTTPS) X-Forwarded-Host: original Host header requested by the client X-Forwarded-For: original IP address of a client (CORRECT) X-Forwarded-Port header: original port that the client used to connect

   Source: Adapted from community discussion — chris_777

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6. Question 66 · 548 in bank

   A developer migrated a legacy application to an AWS Lambda function. The function uses a third-party service to pull data with a series of API calls at the end of each month. The function then processes the data to generate the monthly reports. The function has been working with no issues so far. The third-party service recently issued a restriction to allow a fixed number of API calls each minute and each day. If the API calls exceed the limit for each minute or each day, then the service will produce errors. The API also provides the minute limit and daily limit in the response header. This restriction might extend the overall process to multiple days because the process is consuming more API calls than the available limit. What is the MOST operationally efficient way to refactor the serverless application to accommodate this change?

   • AUse an AWS Step Functions state machine to monitor API failures. Use the Wait state to delay calling the Lambda function.
   • BUse an Amazon Simple Queue Service (Amazon SQS) queue to hold the API calls. Configure the Lambda function to poll the queue within the API threshold limits.
   • CUse an Amazon CloudWatch Logs metric to count the number of API calls. Configure an Amazon CloudWatch alarm that stops the currently running instance of the Lambda function when the metric exceeds the API threshold limits.
   • DUse Amazon Kinesis Data Firehose to batch the API calls and deliver them to an Amazon S3 bucket with an event notification to invoke the Lambda function.

   Show answer

   Answer: A

   Explanation

   A. Use an AWS Step Functions state machine to monitor API failures. Use the Wait state to delay calling the Lambda function: This is a viable and efficient solution. AWS Step Functions can orchestrate the Lambda function invocations and manage the workflow, including handling API call rate limits. The Wait state can be used to introduce delays between API calls to ensure compliance with the rate limits. This approach also allows for handling errors and retries effectively. B. Use an Amazon Simple Queue Service (Amazon SQS) queue to hold the API calls. Configure the Lambda function to poll the queue within the API threshold limits: While using SQS to queue API call requests is a good way to manage workload, it adds complexity to the solution. The Lambda function would need to be modified to manage the queue and ensure API calls are made within the threshold limits. This approach might not be as straightforward and efficient as using Step Functions.

   Source: Adapted from community discussion — SerialiDr

   References

   • AWS documentation

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7. Question 67 · 548 in bank

   A developer has written an AWS Lambda function. The function is CPU-bound. The developer wants to ensure that the function returns responses quickly. How can the developer improve the function's performance?

   • AIncrease the function's CPU core count.
   • BIncrease the function's memory.
   • CIncrease the function's reserved concurrency.
   • DIncrease the function's timeout.

   Show answer

   Answer: B

   Explanation

   Option B is correct, the only adjustable parameter (in terms of hardware) is lambda memory. Increasing lambda memory will result in automatic adjustment of CPU. Lambda memory is adjustable from 128 MB upto 10 GB

   Source: Adapted from community discussion — Kashan6109

   References

   • AWS documentation
   • AWS documentation

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8. Question 68 · 548 in bank

   A developer must analyze performance issues with production-distributed applications written as AWS Lambda functions. These distributed Lambda applications invoke other components that make up the applications. How should the developer identify and troubleshoot the root cause of the performance issues in production?

   • AAdd logging statements to the Lambda functions, then use Amazon CloudWatch to view the logs.
   • BUse AWS CloudTrail and then examine the logs.
   • CUse AWS X-Ray, then examine the segments and errors.
   • DRun Amazon Inspector agents and then analyze performance.

   Show answer

   Answer: C

   Explanation

   The correct answer is (C). AWS X-Ray is the best tool for identifying and addressing the root cause of performance issues in distributed production applications. X-Ray provides an overview of the entire call stack, including the Lambda functions and other components they invoke.

   Source: Adapted from community discussion — Digo30sp

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9. Question 69 · 548 in bank

   A developer wants to deploy a new version of an AWS Elastic Beanstalk application. During deployment, the application must maintain full capacity and avoid service interruption. Additionally, the developer must minimize the cost of additional resources that support the deployment. Which deployment method should the developer use to meet these requirements?

   • AAll at once
   • BRolling with additional batch
   • CBlue/green
   • DImmutable

   Show answer

   Answer: B

   Explanation

   B: Rolling with additional batch , considering "minimize the cost of additional resources" C costly than B, due to double capacity

   Source: Adapted from community discussion — Nagasoracle

   References

   • AWS documentation

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10. Question 70 · 548 in bank

    A developer has observed an increase in bugs in the AWS Lambda functions that a development team has deployed in its Node.js application. To minimize these bugs, the developer wants to implement automated testing of Lambda functions in an environment that closely simulates the Lambda environment. The developer needs to give other developers the ability to run the tests locally. The developer also needs to integrate the tests into the team’s continuous integration and continuous delivery (CI/CD) pipeline before the AWS Cloud Development Kit (AWS CDK) deployment. Which solution will meet these requirements?

    • ACreate sample events based on the Lambda documentation. Create automated test scripts that use the cdk local invoke command to invoke the Lambda functions. Check the response. Document the test scripts for the other developers on the team. Update the CI/CD pipeline to run the test scripts.
    • BInstall a unit testing framework that reproduces the Lambda execution environment. Create sample events based on the Lambda documentation. Invoke the handler function by using a unit testing framework. Check the response. Document how to run the unit testing framework for the other developers on the team. Update the CI/CD pipeline to run the unit testing framework.
    • CInstall the AWS Serverless Application Model (AWS SAM) CLI tool. Use the sam local generate-event command to generate sample events for the automated tests. Create automated test scripts that use the sam local invoke command to invoke the Lambda functions. Check the response. Document the test scripts for the other developers on the team. Update the CI/CD pipeline to run the test scripts.
    • DCreate sample events based on the Lambda documentation. Create a Docker container from the Node.js base image to invoke the Lambda functions. Check the response. Document how to run the Docker container for the other developers on the team. Update the CI/CD pipeline to run the Docker container.

    Show answer

    Answer: C

    Explanation

    This is the most suitable option. AWS SAM CLI is a tool designed for building, testing, and debugging serverless applications, and it includes the ability to locally test Lambda functions. The sam local invoke command allows you to invoke Lambda functions locally in a Docker container that simulates the Lambda execution environment. The sam local generate-event command can be used to generate sample events. This approach allows developers to run tests locally and can be integrated into CI/CD pipelines.

    Source: Adapted from community discussion — SerialiDr

    References

    • AWS documentation

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DVA-C02 practice, question 61. 548 questions available.