Question 1

An application stores images in an S3 bucket. Amazon S3 event notifications are used to trigger a Lambda function that resizes the images. Processing each image takes less than a second. How will AWS Lambda handle the additional traffic?
A) Lambda will scale out to execute the requests concurrently.
B) Lambda will handle the requests sequentially in the order received.
C) Lambda will process multiple images in a single execution.
D) Lambda will add more compute to each execution to reduce processing time.

Accepted Answer

AWS Lambda is designed to automatically scale out to handle incoming requests concurrently, allowing it to process multiple events simultaneously.

Question 2

A Developer is working on an application that tracks hundreds of millions of product reviews in an Amazon DynamoDB table. The records include the data elements shown in the table:  Which field, when used as the partition key, would result in the MOST consistent performance using DynamoDB?
A) starRating
B) reviewID
C) comment
D) productID

Accepted Answer

B

Question 3

Where should an Elastic Beanstalk configuration file named healthcheckur1.config be placed in the application source bundle?
A) In the root of the application
B) In the bin folder
C) In healthcheckur1.config.ebextension under root In healthcheckur1.config.ebextension under root
D) In the .ebextensions folder In the .ebextensions folder

Accepted Answer

Elastic Beanstalk configuration files should be placed in the .ebextensions folder within the application source bundle.

Question 4

A Developer has written a serverless application using multiple AWS services. The business logic is written as a Lambda function which has dependencies on third-party libraries. The Lambda function endpoints will be exposed using Amazon API Gateway. The Lambda function will write the information to Amazon DynamoDB. The Developer is ready to deploy the application but must have the ability to rollback. How can this deployment be automated, based on these requirements?
A) Deploy using Amazon Lambda API operations to create the Lambda function by providing a deployment package.
B) Use an AWS CloudFormation template and use CloudFormation syntax to define the Lambda function resource in the template.
C) Use syntax conforming to the Serverless Application Model in the AWS CloudFormation template to define the Lambda function resource.
D) Create a bash script which uses AWS CLI to package and deploy the application.

Accepted Answer

The answer of A Developer has written a serverless application...

Question 5

A company wants to implement a continuous integration for its workloads on AWS. The company wants to trigger unit test in its pipeline for commits-on its code repository, and wants to be notified of failure events in the pipeline. How can these requirements be met?
A) Store the source code in AWS CodeCommit. Create a CodePipeline to automate unit testing. Use Amazon SNS to trigger notifications of failure events.
B) Store the source code in GitHub. Create a CodePipeline to automate unit testing. Use Amazon SES to trigger notifications of failure events.
C) Store the source code on GitHub. Create a CodePipeline to automate unit testing. Use Amazon CloudWatch to trigger notifications of failure events.
D) Store the source code in AWS CodeCommit. Create a CodePipeline to automate unit testing. Use Amazon CloudWatch to trigger notification of failure events.

Accepted Answer

The answer of A company wants to implement a continuous...

Question 6

A Developer is asked to implement a caching layer in front of Amazon RDS. Cached content is expensive to regenerate in case of service failure. Which implementation below would work while maintaining maximum uptime?
A) Implement Amazon ElastiCache Redis in Cluster Mode
B) Install Redis on an Amazon EC2 instance.
C) Implement Amazon ElastiCache Memcached.
D) Migrate the database to Amazon Redshift.

Accepted Answer

Amazon ElastiCache Redis in Cluster Mode provides high availability and data replication, ensuring maximum uptime and data persistence, which is crucial for expensive-to-regenerate cached content.

Question 7

A Developer is creating a web application that requires authentication, but also needs to support guest access to provide users limited access without having to authenticate. What service can provide support for the application to allow guest access?
A) IAM temporary credentials using AWS STS.
B) Amazon Directory Service
C) Amazon Cognito with unauthenticated access enabled
D) IAM with SAML integration

Accepted Answer

Amazon Cognito with unauthenticated access enabled allows users to access the application without authentication, providing limited access as guests.

Question 8

A serverless application uses an API Gateway and AWS Lambda. Where should the Lambda function store its session information across function calls?
A) In an Amazon DynamoDB table
B) In an Amazon SQS queue
C) In the local filesystem
D) In an SQLite session table using -DSQLITE_ENABLE_SESSION In an SQLite session table using -DSQLITE_ENABLE_SESSION

Accepted Answer

Amazon DynamoDB is a managed NoSQL database service that is well-suited for storing session information across multiple Lambda function calls due to its scalability, low latency, and ability to handle concurrent access.

Question 9

A large e-commerce site is being designed to deliver static objects from Amazon S3. The Amazon S3 bucket will server more than 300 GET requests per second. What should be done to optimize performance? (Choose two.)
A) Integrate Amazon CloudFront with Amazon S3.
B) Enable Amazon S3 cross-region replication.
C) Delete expired Amazon S3 server log files.
D) Configure Amazon S3 lifecycle rules.
E) Randomize Amazon S3 key name prefixes.

Accepted Answer

The answer of A large e-commerce site is being designed...

Question 10

A company is building a stock trading application that requires sub-millisecond latency in processing trading requests. Amazon DynamoDB is used to store all the trading data that is used to process each request. After load testing the application, the development team found that due to data retrieval times, the latency requirement is not satisfied. Because of sudden high spikes in the number of requests, DynamoDB read capacity has to be significantly over-provisioned to avoid throttling. What steps should be taken to meet latency requirements and reduce the cost of running the application?
A) Add Global Secondary Indexes for trading data.
B) Store trading data in Amazon S3 and use Transfer Acceleration.
C) Add retries with exponential back-off for DynamoDB queries
D) Use DynamoDB Accelerator to cache trading data.

Accepted Answer

The answer of A company is building a stock trading...

Question 11

A Developer has created an S3 bucket s3://mycoolapp and has enabled server across logging that points to the folder s3://mycoolapp/logs. The Developer moved 100 KB of Cascading Style Sheets (CSS) documents to the folder s3://mycoolapp/css , and then stopped work. When the developer came back a few days later, the bucket was 50 GB. What is the MOST likely cause of this situation?
A) The CSS files were not compressed and S3 versioning was enabled.
B) S3 replication was enabled on the bucket.
C) Logging into the same bucket caused exponential log growth.
D) An S3 lifecycle policy has moved the entire CSS file to S3 Infrequent Access.

Accepted Answer

The answer of A Developer has created an S3 bucket...

Question 12

A current architecture uses many Lambda functions invoking one another as a large state machine. The coordination of this state machine is legacy custom code that breaks easily. Which AWS Service can help refactor and manage the state machine?
A) AWS Data Pipeline
B) AWS SNS with AWS SQS
C) Amazon Elastic MapReduce
D) AWS Step Functions

Accepted Answer

AWS Step Functions is a service designed to coordinate components of distributed applications and microservices using visual workflows, making it ideal for managing state machines.

Question 13

A Developer is testing a Docker-based application that uses the AWS SDK to interact with Amazon DynamoDB. In the local development environment, the application has used IAM access keys. The application is now ready for deployment onto an ECS cluster. How should the application authenticate with AWS services in production?
A) Configure an ECS task IAM role for the application to use
B) Refactor the application to call AWS STS AssumeRole based on an instance role
C) Configure AWS access key/secret access key environment variables with new credentials
D) Configure the credentials file with a new access key/secret access key

Accepted Answer

Using an ECS task IAM role is the recommended way to provide applications running on ECS with the necessary permissions to interact with AWS services securely, without hardcoding credentials.

Question 14

An application under development is required to store hundreds of video files. The data must be encrypted within the application prior to storage, with a unique key for each video file. How should the Developer code the application?
A) Use the KMS Encrypt API to encrypt the data. Store the encrypted data key and data. Use the KMS Encrypt API to encrypt the data. Store the encrypted data key and data.
B) Use a cryptography library to generate an encryption key for the application. Use the encryption key to encrypt the data. Store the encrypted data.
C) Use the KMS GenerateDataKey API to get a data key. Encrypt the data with the data key. Store the encrypted data key and data. GenerateDataKey API to get a data key. Encrypt the data with the data key. Store the encrypted data key and data.
D) Upload the data to an S3 bucket using server side-encryption with an AWS KMS key.

Accepted Answer

The answer of An application under development is required to...

Question 15

An application is designed to use Amazon SQS to manage messages from many independent senders. Each sender's messages must be processed in the order they are received. Which SQS feature should be implemented by the Developer?
A) Configure each sender with a unique MessageGroupId Configure each sender with a unique MessageGroupId
B) Enable MessageDeduplicationIds on the SQS queue Enable MessageDeduplicationIds on the SQS queue
C) Configure each message with unique MessageGroupIds.
D) Enable ContentBasedDeduplication on the SQS queue ContentBasedDeduplication

Accepted Answer

The answer of An application is designed to use Amazon...

Question 16

An application takes 40 seconds to process instructions received in an Amazon SQS message. Assuming the SQS queue is configured with the default VisibilityTimeout value, what is the BEST way, upon receiving a message, to ensure that no other instances can retrieve a message that has already been processed or is currently being processed?
A) Use the ChangeMessageVisibility API to increase the VisibilityTimeout, then use the DeleteMessage API to delete the message.
B) Use the DeleteMessage API call to delete the message from the queue, then call DeleteQueue API to remove the queue.
C) Use the ChangeMessageVisibility API to decrease the timeout value, then use the DeleteMessage API to delete the message.
D) Use the DeleteMessageVisibility API to cancel the VisibilityTimeout, then use the DeleteMessage API to delete the message.

Accepted Answer

The default VisibilityTimeout for an SQS message is 30 seconds. Since the processing takes 40 seconds, you should use the ChangeMessageVisibility API to increase the VisibilityTimeout to more than 40 seconds to ensure no other instances can process the message during this time. After processing, use the DeleteMessage API to remove the message from the queue.

Question 17

A Developer is creating an Auto Scaling group whose instances need to publish a custom metric to Amazon CloudWatch. Which method would be the MOST secure way to authenticate a CloudWatch PUT request?
A) Create an IAM user with PutMetricData permission and put the user credentials in a private repository; have applications pull the credentials as needed.
B) Create an IAM user with PutMetricData permission, and modify the Auto Scaling launch configuration to inject the user credentials into the instance user data.
C) Modify the CloudWatch metric policies to allow the PutMetricData permission to instances from the Auto Scaling group.
D) Create an IAM role with PutMetricData permission and modify the Auto Scaling launching configuration to launch instances using that role.

Accepted Answer

Using an IAM role with the necessary permissions and associating it with the instances ensures that temporary credentials are securely provided to the instances, avoiding the need to hard-code or manually manage credentials.

Question 18

An application reads data from an Amazon DynamoDB table. Several times a day, for a period of 15 seconds, the application receives multiple ProvisionedThroughputExceeded errors. How should this exception be handled?
A) Create a new global secondary index for the table to help with the additional requests.
B) Retry the failed read requests with exponential backoff.
C) Immediately retry the failed read requests.
D) Use the DynamoDB "UpdateItem" API to increase the provisioned throughput capacity of the table.

Accepted Answer

Exponential backoff is a standard error-handling strategy for network applications in which the client retries requests with increasing delays between attempts. This approach helps to manage and reduce the load on the system, which is particularly useful when dealing with ProvisionedThroughputExceeded errors in DynamoDB.

Question 19

A deployment package uses the AWS CLI to copy files into any S3 bucket in the account, using access keys stored in environment variables. The package is running on EC2 instances, and the instances have been modified to run with an assumed IAM role and a more restrictive policy that allows access to only one bucket. After the change, the Developer logs into the host and still has the ability to write into all of the S3 buckets in that account. What is the MOST likely cause of this situation?
A) An IAM inline policy is being used on the IAM role
B) An IAM managed policy is being used on the IAM role
C) The AWS CLI is corrupt and needs to be reinstalled
D) The AWS credential provider looks for instance profile credentials last

Accepted Answer

The answer of A deployment package uses the AWS CLI...

Question 20

When writing a Lambda function, what is the benefit of instantiating AWS clients outside the scope of the handler?
A) Legibility and stylistic convention
B) Taking advantage of connection re-use
C) Better error handling
D) Creating a new instance per invocation

Accepted Answer

Instantiating AWS clients outside the handler allows the Lambda function to reuse the client connection across multiple invocations, improving performance by reducing the overhead of creating a new client each time.

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

An application stores images in an S3 bucket. Amazon S3 event notifications are used to trigger a Lambda function that resizes the images. Processing each image takes less than a second. How will AWS Lambda handle the additional traffic?

A Developer is working on an application that tracks hundreds of millions of product reviews in an Amazon DynamoDB table. The records include the data elements shown in the table: Which field, when used as the partition key, would result in the MOST consistent performance using DynamoDB?

Where should an Elastic Beanstalk configuration file named healthcheckur1.config be placed in the application source bundle?

A company wants to implement a continuous integration for its workloads on AWS. The company wants to trigger unit test in its pipeline for commits-on its code repository, and wants to be notified of failure events in the pipeline. How can these requirements be met?

A Developer is asked to implement a caching layer in front of Amazon RDS. Cached content is expensive to regenerate in case of service failure. Which implementation below would work while maintaining maximum uptime?

A Developer is creating a web application that requires authentication, but also needs to support guest access to provide users limited access without having to authenticate. What service can provide support for the application to allow guest access?

A serverless application uses an API Gateway and AWS Lambda. Where should the Lambda function store its session information across function calls?

A large e-commerce site is being designed to deliver static objects from Amazon S3. The Amazon S3 bucket will server more than 300 GET requests per second. What should be done to optimize performance? (Choose two.)

A current architecture uses many Lambda functions invoking one another as a large state machine. The coordination of this state machine is legacy custom code that breaks easily. Which AWS Service can help refactor and manage the state machine?

An application under development is required to store hundreds of video files. The data must be encrypted within the application prior to storage, with a unique key for each video file. How should the Developer code the application?

An application is designed to use Amazon SQS to manage messages from many independent senders. Each sender's messages must be processed in the order they are received. Which SQS feature should be implemented by the Developer?

A Developer is creating an Auto Scaling group whose instances need to publish a custom metric to Amazon CloudWatch. Which method would be the MOST secure way to authenticate a CloudWatch PUT request?

An application reads data from an Amazon DynamoDB table. Several times a day, for a period of 15 seconds, the application receives multiple ProvisionedThroughputExceeded errors. How should this exception be handled?

When writing a Lambda function, what is the benefit of instantiating AWS clients outside the scope of the handler?