Amazon DVA-C01 Online Practice Questions and Exam Preparation

Amazon DVA-C01 Online Questions & Answers

• Question 181:

  A company's ecommerce website is experiencing massive traffic spikes, which are causing performance problems in the company database. Users are reporting that accessing the website takes a long time A developer wants to implement a caching layer using Amazon ElastiCache. The website is required to be responsive no matter which product a user views, and the updates to product information and prices must be strongly consistent

  A. Which cache writing policy will satisfy these requirements?

  B. Write to the cache directly and sync the backend at a later time.

  C. Write to the backend first and wait for the cache to expire.

  D. Write to the cache and the backend at the same time

  E. Write to the backend first and invalidate the cache

  Correct Answer: E

• Question 182:

  A software company needs to make sure user-uploaded documents are securely stored in Amazon S3. The documents must be encrypted at rest in Amazon S3. The company does not want to manage the security infrastructure in-house, but the company still needs extra protection to ensure it has control over its encryption keys due to industry regulations Which encryption strategy should a developer use to meet these requirements?

  A. Server-side encryption with Amazon S3 managed keys (SSE-S3)

  B. Server-side encryption with customer-provided encryption keys (SSE-C)

  C. Server-side encryption with AWS KMS managed keys (SSE-KMS)

  D. Client-side encryption

  Correct Answer: B

  Server side encryption with customer managed keys

• Question 183:

  A developer uses Amazon S3 buckets for static website hosting. The developer creates one S3 bucket for the code and another S3 bucket for the assets, such as image and video files. Access is denied when a user attempts to access the assets bucket from the code bucket, with the website application showing a 403 error How should the developer solve this issue?

  A. Create an 1AM role and apply it to the assets bucket for the code bucket to be granted access

  B. Edit the bucket policy of the assets bucket to open access to all principals

  C. Edit the cross-origin resource sharing (CORS) configuration of the assets bucket to allow any origin to access the assets

  D. Change the code bucket to use AWS Lambda functions instead of static website hosting.

  Correct Answer: C

  The Web Site code will run on the client machine (the browser). It is sad it will fetch the asset from the other bucket so there is some JS code. Bucket B is considered another origin so we have a CORS error here. It's C.

  It can't be because there is no point in adding a bucket policy to allow all principles because we are accessing the file from the client machine not within aws

  Note that CORS can result in 403 errors in some cases.

  Example: https://medium.com/collaborne-engineering/403-cursed-by-cors-d1700cab754

  https://docs.aws.amazon.com/AmazonS3/latest/dev/cors-troubleshooting.html

• Question 184:

  A development team is creating a new application designed to run on AWS. While the test and production environments will run on Amazon EC2 instances, developers will each run their own environment on their laptops. Which of the following is the simplest and MOST secure way to access AWS services from the local development machines?

  A. Use an 1AM role to assume a role and execute API calls using the role.

  B. Create an 1AM user to be shared with the entire development team, provide the development team with the access key.

  C. Create an 1AM user for each developer on the team: provide each developer with a unique access key

  D. Set up a federation through an Amazon Cognito user pool.

  Correct Answer: A

• Question 185:

  A developer is creating an application to process a large number of requests. Requests must be processed in order, and each request should be processed only once. How should Amazon SQS be deployed to achieve this?

  A. Configure First in First out (FIFO) delivery in a standard Amazon SQS queue to process requests.

  B. Use an SQS FIFO queue to process requests.

  C. Use the SetOrder attribute to ensure sequential request processing.

  D. Convert the standard queue to a FIFO queue by renaming the queue to use the .fifo suffix.

  Correct Answer: B

  Reference: https://medium.com/awesome-cloud/aws-difference-between-sqs-standard-and-fifo-first-in-first-out-queues-28d1ea5e153

• Question 186:

  A developer is planning to use an Amazon API Gateway and AWS Lambda to provide a REST API. The developer will have three distinct environments to manage: development, test, and production. How should the application be deployed while minimizing the number of resources to manage?

  A. Create a separate API Gateway and separate Lambda function for each environment in the same Region.

  B. Assign a Region for each environment and deploy API Gateway and Lambda to each Region.

  C. Create one API Gateway with multiple stages with one Lambda function with multiple aliases.

  D. Create one API Gateway and one Lambda function, and use a REST parameter to identify the environment.

  Correct Answer: C

  Reference: https://aws.amazon.com/blogs/compute/using-api-gateway-stage-variables-to-manage-lambda-functions/

• Question 187:

  A developer wants to ensure the Amazon EC2 instances in AWS Elastic Beanstalk execute a certain set of commands before the application is ready to use. Which Elastic Beanstalk feature will allow the developer to accomplish this?

  A. Rolling update

  B. Immutable update

  C. User data

  D. .ebextensions

  Correct Answer: D

  Reference: https://docs.aws.amazon.com/elasticbeanstalk/latest/dg/customize-containers-ec2.html

• Question 188:

  A development team is creating a new application designed to run on AWS. While the test and production environments will run on Amazon EC2 instances, developers will each run their own environment on their laptops. Which of the following is the simplest and MOST secure way to access AWS services from the local development machines?

  A. Use an IAM role to assume a role and execute API calls using the role.

  B. Create an IAM user to be shared with the entire development team; provide the development team with the access key.

  C. Create an IAM user for each developer on the team; provide each developer with a unique access key.

  D. Set up a federation through an Amazon Cognito user pool.

  Correct Answer: A

• Question 189:

  A developer is building a WebSocket API using Amazon API Gateway. The payload sent to this API is JSON that includes an action key. This key can have three different values: create, update, and remove. The developer must integrate with different routes based on the value of the action key of the incoming JSON payload.

  How can the developer accomplish this task with the LEAST amount of configuration?

  A. Deploy the WebSocket API to three stages for the respective routes: create, update, and remove

  B. Create a new route key and set the name as action

  C. Set the value of the route selection expression to action

  D. Set the value of the route selection expression to $request.body.action

  Correct Answer: D

• Question 190:

  An application takes longer than expected to process an Amazon SQS message.

  What should the developer do to the application so that other instances do not pick up the same message?

  A. Make a ReceiveMessage call to get the same message again from the queue

  B. Issue a DeleteMessage call to delete the message from the queue

  C. Use SendMessage to pass the message to the dead letter queue

  D. Send a ChangeMessageVisibility call to extend VisibilityTimeout

  Correct Answer: D

  Visibility Timeout is used to hide messages from other consumers when one of the consumers is processing the message. In the above case, when one of the Amazon EC2 instance is processing messages from the Amazon SQS queue, due to load on instance it is taking time to process messages. Within that time period visibility timeout is expired and another EC2 instance is processing the same message and sending updates to users. To avoid multiple processing of the same message, Visibility timeout can be increased so that Amazon EC2 processes the message before visibility timeout expires.