Question 1

A Developer is writing an application that will run on Amazon EC2 instances in an Auto Scaling group. The Developer wants to externalize session state to support the application. Which services will meet these needs? (Choose two.)

Accepted Answer

The answer of A Developer is writing an application that...

Question 2

A Developer is trying to make API calls using SDK. The IAM user credentials used by the application require multi-factor authentication for all API calls. Which method the Developer use to access the multi-factor authentication protected API?

Accepted Answer

The GetSessionToken API is used to obtain temporary credentials that include multi-factor authentication (MFA) when the IAM user credentials require MFA for API calls.

Question 3

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. Which cache writing policy will satisfy these requirements?

Accepted Answer

The answer of A company's ecommerce website is experiencing massive...

Question 4

The development team is working on an API that will be served from Amazon API gateway. The API will be served from three environments: development, test, and production. The API Gateway is configured to use 237 GB of cache in all three stages. Which is the MOST cost-efficient deployment strategy?

Accepted Answer

Enabling the cache only when needed for development and test environments reduces unnecessary costs, as caching can be expensive.

Question 5

A company is migrating from a monolithic architecture to a microservices-based architecture. The Developers need to refactor the application so that the many microservices can asynchronously communicate with each other without impacting performance. Use of which managed AWS services will enable asynchronous message passing? (Choose two.)

Accepted Answer

Amazon SQS (Simple Queue Service) and Amazon SNS (Simple Notification Service) are both managed AWS services that enable asynchronous message passing. SQS is a message queuing service that allows microservices to send and receive messages without having to be directly connected to each other. SNS is a notification service that allows microservices to subscribe to topics and receive notifications when messages are published to those topics.

Question 6

A company has an application that logs all information to Amazon S3. Whenever there is a new log file, an AWS Lambda function is invoked to process the log files. The code works, gathering all of the necessary information. However, when checking the Lambda function logs, duplicate entries with the same request ID are found. What is causing the duplicate entries?

Accepted Answer

Lambda functions can be retried automatically if they fail, leading to duplicate entries with the same request ID.

Question 7

A Developer is working on a serverless project based in Java. Initial testing shows a cold start takes about 8 seconds on average for AWS Lambda functions. What should the Developer do to reduce the cold start time? (Choose two.)

Accepted Answer

The answer of A Developer is working on a serverless...

Question 8

A Developer writes an AWS Lambda function and uploads the code in a .ZIP file to Amazon S3. The Developer makes changes to the code and uploads a new .ZIP file to Amazon S3. However, Lambda executes the earlier code. How can the Developer fix this in the LEAST disruptive way?

Accepted Answer

The update-function-code API updates the code of an existing Lambda function. This is the least disruptive way to update the code because it does not require creating a new function or removing the old one.

Question 9

While developing an application that runs on Amazon EC2 in an Amazon VPC, a Developer identifies the need for centralized storage of application-level logs. Which AWS service can be used to securely store these logs?

Accepted Answer

Amazon CloudWatch Logs is designed to monitor, store, and access log files from Amazon EC2 instances, AWS CloudTrail, and other sources, making it suitable for centralized storage of application-level logs.

Question 10

An application is running on a cluster of Amazon EC2 instances. While trying to read objects stored within a single Amazon S3 bucket that are encrypted with server-side encryption with AWS KMS managed keys (SSE-KMS), the application receives the following error:  Which combination of steps should be taken to prevent this failure? (Choose two.)

Accepted Answer

The answer of An application is running on a cluster...

Question 11

An AWS Lambda function generates a 3MB JSON file and then uploads it to an Amazon S3 bucket daily. The file contains sensitive information, so the Developer must ensure that it is encrypted before uploading to the bucket. Which of the following modifications should the Developer make to ensure that the data is encrypted before uploading it to the bucket?

Accepted Answer

The Developer should use the GenerateDataKey API to generate a data key, then use that data key to encrypt the file in the Lambda function code before uploading it to S3. This ensures that the data is encrypted before it is uploaded.

Question 12

A nightly batch job loads 1 million new records into a DynamoDB table. The records are only needed for one hour, and the table needs to be empty by the next night's batch job. Which is the MOST efficient and cost-effective method to provide an empty table?

Accepted Answer

Use DeleteItem using a ConditionExpression is the most efficient and cost-effective method to provide an empty table. This is because it only deletes the records that match the condition expression, which in this case is all of the records in the table. This is more efficient than using BatchWriteItem, which would require multiple API calls to delete all of the records in the table. It is also more efficient than writing a recursive function that scans and calls out DeleteItem, which would require multiple API calls for each record in the table. Finally, it is more efficient than creating and then deleting the table after the task has completed, which would require two API calls.

Question 13

A company has a web application that uses an Amazon Cognito user pool for authentication. The company wants to create a login page with the company logo. What should a Developer do to meet these requirements?

Accepted Answer

The answer of A company has a web application that...

Question 14

A Developer wants to find a list of items in a global secondary index from an Amazon DynamoDB table. Which DynamoDB API call can the Developer use in order to consume the LEAST number of read capacity units?

Accepted Answer

Query operation using eventually-consistent reads consumes the least number of read capacity units because it is more efficient than a scan and eventually-consistent reads use fewer resources than strongly-consistent reads.

Question 15

A Developer has created a new AWS IAM user that has s3 putObject permission to write to a specific Amazon S3 bucket. This S3 bucket uses server-side encryption with AWS KMS managed (SSE-KMS) as the default encryption. Using the access key and secret key of the IAM user, the application received an access denied error when calling the PutObject API. How can this issue be resolved?

Accepted Answer

The IAM user needs permission to use the KMS key for encryption, specifically the kms:GenerateDataKey action, to successfully upload objects to an S3 bucket with SSE-KMS encryption.

Question 16

To include objects defined by the AWS Serverless Application Model (SAM) in an AWS CloudFormation template, in addition to Resources, what section MUST be included in the document root?

Accepted Answer

The answer of To include objects defined by the AWS...

Question 17

A Developer is writing a mobile application that allows users to view images from an S3 bucket. The users must be able to log in with their Amazon login, as well as Facebook® and/or Google® accounts. How can the Developer provide this authentication functionality?

Accepted Answer

Amazon Cognito with web identity federation allows users to log in using Amazon, Facebook, and Google accounts, providing the necessary authentication functionality for the application.

Question 18

A Developer is creating a template that uses AWS CloudFormation to deploy an application. This application is serverless and uses Amazon API Gateway, Amazon DynamoDB, and AWS Lambda. Which tool should the Developer use to define simplified syntax for expressing serverless resources?

Accepted Answer

The AWS Serverless Application Model (AWS SAM) is a framework that extends AWS CloudFormation to provide a simplified syntax for expressing serverless resources such as functions, APIs, and databases.

Question 19

An AWS Elastic Beanstalk application needs to be deployed in multiple regions and requires a different Amazon Machine Image (AMI) in each region. Which AWS CloudFormation template key can be used to specify the correct AMI for each region?

Accepted Answer

Mappings in AWS CloudFormation templates allow you to create a map of keys and associated values that you can use to specify different AMIs for different regions.

Question 20

A Development team has pushed out 10 applications running on several Amazon EC2 instances. The Operations team is asking for a graphical representation of one key performance metric for each application. These metrics should be available on one screen for easy monitoring. Which steps should the Developer take to accomplish this using Amazon CloudWatch?

Accepted Answer

The answer of A Development team has pushed out 10...

Exam 6: AWS Certified Developer Associate (DVA-C01)