DVA-C02 Development with AWS Services Practice Test 17 — 15 Questions

Question 1

A developer is configuring an Amazon S3 bucket for static website hosting. The website includes JavaScript that makes AJAX calls to an API Gateway endpoint. Which TWO actions should the developer take to allow cross-origin requests?

Accepted Answer

Enable CORS on the API Gateway API.. Options A and C are correct. Option A: S3 bucket policy can allow cross-origin access to the bucket itself, but for API Gateway, CORS must be enabled on the API. Option B is incorrect because the CORS configuration should be on the API Gateway, not the S3 bucket. Option C: Enabling CORS on API Gateway allows the browser to make cross-origin requests. Option D is incorrect because CloudFront does not inherently handle CORS; it must be configured. Option E is incorrect because Lambda functions do not handle CORS directly; API Gateway does.

Answer

Use Amazon CloudFront to serve the website and set CORS headers.

Answer

Add a CORS configuration to the S3 bucket.

Answer

Modify the Lambda function to include CORS headers in the response.

Question 2

A company uses AWS CloudFormation to deploy infrastructure. A developer needs to update a stack that includes an RDS DB instance. The update requires modifying the DB instance's DB engine version. Which THREE strategies can the developer use to minimize downtime during the update?

Accepted Answer

Use the RDS modify-db-instance command to upgrade the engine version in-place.. Options A, B, and D are correct. Option A: RDS supports upgrading to a new engine version without data loss. Option B: Creating a read replica, promoting it, and updating the stack can reduce downtime. Option D: Using a blue/green deployment with RDS Blue/Green Deployments allows switching with minimal downtime. Option C is incorrect because deleting the stack would cause data loss. Option E is incorrect because modifying the stack without any strategy may cause downtime.

Answer

Update the stack directly by modifying the DB engine version property in the template.

Answer

Delete the current stack and create a new stack with the new engine version.

Question 3

A developer is building a serverless application using AWS Lambda. The Lambda function needs to access a VPC to connect to an RDS database. Which TWO resources must the developer configure to allow the Lambda function to access the VPC?

Accepted Answer

A security group that allows inbound/outbound traffic to the RDS database.. Options B and D are correct. Option B: Lambda functions must be configured with a VPC subnet to be placed in the VPC. Option D: A security group must be attached to the Lambda function to control traffic. Option A is incorrect because an internet gateway is not needed for private VPC access. Option C is incorrect because a NAT gateway is for outbound internet access, not for accessing RDS within the VPC. Option E is incorrect because an IAM role is for permissions, not network connectivity.

Answer

A NAT gateway in the VPC.

Answer

An IAM role with permissions to access RDS.

Answer

An internet gateway attached to the VPC.

Question 4

A developer is building a serverless application using AWS Lambda to process images uploaded to an S3 bucket. The Lambda function needs to resize the image and store the result in another S3 bucket. The developer notices that the Lambda function fails intermittently with timeout errors for large images. What is the MOST efficient solution to resolve this issue?

Accepted Answer

Increase the Lambda function timeout and memory allocation to accommodate larger images.. The correct answer is B. Increasing the Lambda timeout and memory allows the function to handle larger images. Option A is wrong because Lambda does not support multi-threading by default and would not help with a single large image. Option C is wrong because Step Functions add complexity without addressing the root cause. Option D is wrong because larger images do not cause concurrent execution limits to be reached; the issue is timeout.

Answer

Limit the S3 event notification to only trigger for images smaller than 5 MB.

Answer

Refactor the Lambda function to use multi-threading for parallel processing of image chunks.

Answer

Use AWS Step Functions to orchestrate the image processing in smaller steps.

Question 5

A company runs a containerized application on Amazon ECS using Fargate launch type. The application needs to read and write files to a shared file system across multiple tasks. The development team wants a solution that provides high throughput and is POSIX-compliant. Which storage solution should the team use?

Accepted Answer

Amazon EFS. The correct answer is C. Amazon EFS provides a scalable, POSIX-compliant file system that can be mounted by multiple ECS tasks. Option A is wrong because S3 is object storage, not POSIX-compliant. Option B is wrong because EBS volumes can only be attached to one instance at a time. Option D is wrong because FSx for Windows File Server is not POSIX-compliant.

Answer

Amazon S3 with mountpoint-s3

Answer

Amazon EBS with multi-attach enabled

Answer

Amazon FSx for Windows File Server

Question 6

A developer needs to store application configuration data (key-value pairs) that can be accessed by multiple microservices running on EC2 instances. The configuration data changes infrequently but must be retrievable with low latency. Which AWS service should the developer use?

Accepted Answer

AWS AppConfig. The correct answer is B. AWS AppConfig is designed to manage application configuration data and supports feature flags and dynamic configuration. Option A is wrong because Systems Manager Parameter Store is also suitable but AppConfig is more specialized for this use case. However, according to best practices, AppConfig is the recommended service for application configuration. Option C is wrong because DynamoDB is a database, not a configuration store. Option D is wrong because S3 is object storage with higher latency.

Answer

AWS Systems Manager Parameter Store

Answer

Amazon S3

Answer

Amazon DynamoDB

Question 7

A developer is deploying an application using AWS CodeDeploy with an in-place deployment configuration. The application runs on an EC2 instance behind an Application Load Balancer. The deployment fails because the health check fails after the new version is installed. What should the developer do to prevent the deployment from failing due to health checks?

Accepted Answer

Configure a longer health check grace period in the CodeDeploy application specification.. The correct answer is D. Configuring a longer health check grace period allows the application to start and stabilize before the load balancer checks its health. Option A is wrong because deregistering the instance during deployment is not a standard practice and may cause traffic loss. Option B is wrong because a blue/green deployment is a different strategy, not a fix for in-place deployment. Option C is wrong because increasing the interval alone does not provide a grace period.

Answer

Deregister the instance from the target group before deployment and register it after.

Answer

Switch to a blue/green deployment strategy.

Answer

Increase the health check interval on the load balancer.

Question 8

A company is using AWS Lambda to process messages from an Amazon SQS queue. The Lambda function is configured with a reserved concurrency of 10. The SQS queue receives a burst of 1000 messages. The Lambda function processes each message in about 5 seconds. What is the most likely behavior of the system?

Accepted Answer

Lambda processes up to 10 messages concurrently, and the rest remain in the queue until processing capacity is available.. The correct answer is D. Lambda will poll the SQS queue, but with reserved concurrency of 10, only 10 Lambda functions can run concurrently. The remaining messages will remain in the queue until the running functions finish. Option A is wrong because Lambda does not block the queue. Option B is wrong because Lambda does not scale beyond reserved concurrency. Option C is wrong because Lambda does not automatically increase concurrency beyond the limit.

Answer

Lambda rejects the messages and sends them to the dead-letter queue.

Answer

Lambda automatically scales up to 1000 concurrent executions to process all messages quickly.

Answer

Lambda increases the reserved concurrency to accommodate the burst.

Question 9

A developer is building a REST API using Amazon API Gateway and AWS Lambda. The API should allow users to retrieve data from an Amazon DynamoDB table. The developer wants to minimize latency for frequently accessed data. What should the developer do?

Accepted Answer

Use DynamoDB Accelerator (DAX) as a caching layer.. The correct answer is C. Using DynamoDB Accelerator (DAX) provides an in-memory cache that reduces latency for frequently accessed data. Option A is wrong because API Gateway caching caches the entire API response, which may not be efficient for all requests. Option B is wrong because increasing Lambda memory does not directly reduce latency for DynamoDB queries. Option D is wrong because CloudFront is for content delivery, not for reducing database latency.

Answer

Deploy a CloudFront distribution in front of the API Gateway.

Answer

Increase the Lambda function memory to improve performance.

Answer

Enable API Gateway caching.

Question 10

A company is running a monolithic application on an EC2 instance. The application currently stores session state in local memory on the instance. The company plans to scale the application horizontally by adding more instances behind a load balancer. What change is required to ensure that session state is preserved across requests?

Accepted Answer

Use Amazon ElastiCache to store session state externally.. The correct answer is D. Using ElastiCache (Redis or Memcached) provides a centralized, scalable session store accessible from all instances. Option A is wrong because S3 is not designed for low-latency session storage. Option B is wrong because RDS is a relational database, which can work but is not optimized for session storage. Option C is wrong because increasing instance size does not enable session sharing across instances.

Answer

Store session data in Amazon S3 and retrieve it on each request.

Answer

Increase the EC2 instance size to handle more sessions per instance.

Answer

Use an Amazon RDS database to store session state.

Question 11

A developer is creating an AWS Lambda function that processes events from an Amazon S3 bucket. The function writes logs to Amazon CloudWatch Logs. The developer wants to ensure that the Lambda function has the minimum required permissions. Which IAM policy should be attached to the Lambda execution role?

Accepted Answer

A policy that includes 'logs:CreateLogGroup', 'logs:CreateLogStream', 'logs:PutLogEvents', and 's3:GetObject' on the specific bucket.. The correct answer is A. The policy grants permissions to write logs to CloudWatch Logs and to get objects from the specific S3 bucket. Option B is wrong because it uses a wildcard for S3 actions, which grants more permissions than needed. Option C is wrong because it grants unnecessary S3 list permissions. Option D is wrong because it uses 's3:*' which is too permissive.

Answer

A policy that includes 'logs:CreateLogStream', 'logs:PutLogEvents', and 's3:*' on the bucket.

Answer

A policy that includes 'logs:*' and 's3:*' on the bucket.

Answer

A policy that includes 'logs:PutLogEvents' and 's3:ListBucket' on the bucket.

Question 12

A developer is building a serverless application and wants to invoke an AWS Lambda function every hour to perform a cleanup task. Which AWS service should the developer use to schedule the invocation?

Accepted Answer

Amazon EventBridge (CloudWatch Events). The correct answer is B. Amazon CloudWatch Events (now Amazon EventBridge) can schedule events to trigger Lambda functions at specified intervals. Option A is wrong because SQS is a message queue, not a scheduler. Option C is wrong because Step Functions orchestrates workflows but does not schedule invocations directly. Option D is wrong because SNS is a notification service.

Answer

AWS Step Functions

Answer

Amazon SNS

Answer

Amazon SQS

Question 13

A developer is designing a system that requires processing of streaming data from IoT devices in real time. The processed data will be stored in an S3 bucket for analytics. Which AWS services should the developer use together to build this solution? (Choose TWO.)

Accepted Answer

Amazon Kinesis Data Firehose. The correct answers are A and D. Amazon Kinesis Data Streams ingests streaming data, and Amazon Kinesis Data Firehose delivers that data to S3. Option B is wrong because Lambda is not a streaming ingestion service. Option C is wrong because SQS is for message queues, not real-time streaming. Option E is wrong because S3 is the destination, not the processing service.

Answer

AWS Lambda

Answer

Amazon S3

Answer

Amazon SQS

Question 14

A company has a web application running on Amazon ECS with Fargate launch type. The application needs to store and retrieve user session data. The sessions are small and require very low latency access. The development team wants a fully managed solution. Which storage options meet these requirements? (Choose TWO.)

Accepted Answer

Amazon DynamoDB. The correct answers are C and D. Amazon ElastiCache for Redis provides in-memory caching with low latency, and Amazon DynamoDB provides fast NoSQL storage. Option A is wrong because EFS is a file system, not optimized for key-value session data. Option B is wrong because RDS is relational and adds latency. Option E is wrong because S3 is object storage with higher latency.

Answer

Amazon S3

Answer

Amazon EFS

Answer

Amazon RDS for PostgreSQL

Question 15

A developer is deploying a serverless application using the AWS Serverless Application Model (SAM). The application consists of an API Gateway, Lambda functions, and a DynamoDB table. The developer wants to define and deploy this infrastructure as code. Which files and tools are required? (Choose THREE.)

Accepted Answer

aws cloudformation deploy command. The correct answers are B, C, and D. SAM uses a template.yaml file, and the aws cloudformation package and deploy commands are used to deploy. Option A is wrong because Terraform is a separate tool. Option E is wrong because the AWS CLI alone cannot handle SAM packaging and deployment.

Answer

Terraform configuration files

Answer

AWS CLI with aws lambda update-function-code command