DVA-C02 Practice Test 2 — 10 Questions

Question 1

A developer is building a serverless application using AWS Lambda and Amazon API Gateway. The developer wants to enable caching for API responses to reduce latency and cost. Which step is REQUIRED to enable caching?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Create a cache cluster in API Gateway for the stage. API Gateway caching requires a dedicated cache cluster to be enabled and configured at the stage level. This cluster stores API responses and serves them directly from the cache for identical requests, reducing the number of calls to the backend Lambda function and lowering latency. Without creating and enabling this cache cluster in the API Gateway stage settings, caching cannot function.

Answer

Enable caching in the Lambda function code

Answer

Set the TTL in the API Gateway method request integration

Answer

Use Amazon ElastiCache and modify the Lambda function to check cache

Question 2

A company is deploying a new web application on Amazon EC2 instances behind an Application Load Balancer. The application must be deployed with no downtime. The deployment uses AWS CodeDeploy with a Blue/Green deployment configuration. Which TWO actions should be taken to achieve zero-downtime deployment? (Choose TWO.)

Accepted Answer

Create a new Auto Scaling group with the new application version and register it with the ALB.. In a Blue/Green deployment, you create a new Auto Scaling group with the new application version and register it with the existing ALB. Option E is correct because after the new environment is ready, you gradually shift traffic from the old environment to the new environment using the ALB to ensure zero downtime. Option A is incorrect because you should reuse the existing ALB to avoid re-creating DNS and other configurations. Option C is incorrect because updating the existing Auto Scaling group in-place would cause downtime (rolling update) rather than a true Blue/Green deployment. Option D is incorrect because terminating old instances immediately could cause downtime if the new environment fails; you should allow rollback by keeping old instances until traffic is fully shifted.

Answer

Create a new load balancer for the new environment.

Answer

Update the existing Auto Scaling group with the new application version.

Answer

Terminate the old EC2 instances immediately after deploying the new ones.

Question 3

A developer is troubleshooting a slow RDS MySQL instance. Which TWO metrics in Amazon CloudWatch should the developer examine first?

Accepted Answer

CPUUtilization. The correct metrics to examine first for a slow RDS MySQL instance are CPUUtilization and ReadLatency. High CPUUtilization indicates that the instance is under heavy load, possibly from inefficient queries or inadequate compute capacity. High ReadLatency suggests slow I/O, which could be due to disk contention or suboptimal queries. NetworkReceiveThroughput (A) is related to network traffic, not database performance. SwapUsage (B) is not typically a primary metric for RDS performance. FreeStorageSpace (D) indicates storage capacity but does not directly measure performance. Therefore, options C and E are the correct choices.

Answer

NetworkReceiveThroughput

Answer

SwapUsage

Answer

FreeStorageSpace

Question 4

A developer is deploying a serverless application using AWS CloudFormation. The stack creation fails with the error 'CREATE_FAILED: The following resource(s) failed to create: [MyLambdaFunction]'. The developer checks the CloudFormation events and sees 'Resource creation cancelled'. What is the most likely cause?

Accepted Answer

Another resource in the stack failed, triggering a rollback and cancelling the Lambda creation.. The error 'Resource creation cancelled' indicates that the creation of the Lambda function was aborted because another resource in the stack failed. CloudFormation by default rolls back the stack on failure, cancelling any in-progress resource creations. Thus, option C is correct. Option A is incorrect because large code would cause a different error (e.g., 'RequestEntityTooLargeException'). Option B is incorrect because a timeout would show 'CREATE_FAILED' with a timeout message, not 'cancelled'. Option D is incorrect because missing permissions would result in a different error (e.g., 'AccessDeniedException') during invocation, not creation.

Answer

The Lambda function code is too large and exceeds the deployment limit.

Answer

The Lambda function creation timed out due to a network issue.

Answer

The Lambda function's execution role is missing permissions.

Question 5

A developer is optimizing an S3 bucket for static website hosting. The site has a main page (index.html) and an error page (error.html). Users report seeing a generic 403 error instead of the error page when accessing a missing object. What is the likely cause?

Accepted Answer

The Error document field in the static website hosting configuration is not set to error.html.. When static website hosting is enabled on an S3 bucket, the Error Document field specifies the object served when a 403 or 404 error occurs. If this field is not set to error.html, S3 returns its generic 403 error response instead of the custom error page. The correct answer is B because the Error document configuration is missing or incorrect.

Answer

The bucket policy denies access to the error.html object.

Answer

The index.html is missing from the bucket.

Answer

The error.html object has incorrect permissions.

Question 6

A developer is building a microservices application that processes event messages from multiple sources. The application requires at-least-once delivery, but message ordering is not important. Which Amazon SQS queue type should the developer use?

Accepted Answer

Standard queue. Amazon SQS Standard queues provide at-least-once delivery and best-effort ordering, making them ideal for microservices that can tolerate duplicate messages and do not require strict message sequencing. Since the application processes events from multiple sources and message ordering is not important, a Standard queue meets the requirements without the throughput limitations of FIFO queues.

Answer

FIFO queue

Answer

Dead-letter queue

Answer

Delay queue

Question 7

A developer is building a serverless application using AWS Lambda and Amazon API Gateway. The developer wants to enable caching for API responses to reduce latency and cost. Which step is REQUIRED to enable caching?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Increase the Lambda function timeout and memory allocation to accommodate larger images.. Increasing the Lambda function timeout and memory allocation directly addresses the root cause of the failure: large images require more processing time and memory. Lambda's CPU and I/O throughput scale proportionally with allocated memory, so raising both parameters provides the necessary resources to complete the resize operation within the function's execution environment.

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 8

A developer is building a serverless API using Amazon API Gateway and AWS Lambda. The API accepts JSON payloads in the request body. The developer wants to ensure that incoming requests have a valid structure before being passed to the Lambda function to reduce unnecessary invocations. Which API Gateway feature should the developer use?

Accepted Answer

Request validation using models and request validators. API Gateway's request validation feature allows you to define a JSON Schema model for the request body and attach a request validator to the method. This validates the payload structure before the request reaches the Lambda function, preventing invalid payloads from triggering unnecessary invocations and reducing costs.

Answer

Usage plans with API keys

Answer

WAF (AWS WAF) integration

Answer

Custom authorizer (Lambda authorizer)

Question 9

A developer wants to store application configuration securely and retrieve it programmatically from EC2 instances. The configuration includes database passwords and API keys. Which AWS service should be used?

Accepted Answer

AWS Systems Manager Parameter Store with SecureString. AWS Systems Manager Parameter Store with SecureString is the correct choice because it is purpose-built for securely storing sensitive configuration data like database passwords and API keys. It integrates with AWS KMS for encryption at rest, supports versioning, and allows EC2 instances to retrieve values via the AWS CLI or SDK using IAM roles, eliminating the need to hardcode secrets.

Answer

EC2 user data

Answer

Amazon S3 with server-side encryption

Answer

AWS CloudFormation template parameters

Question 10

A company runs an application on Amazon EC2 instances that need to read data from an Amazon DynamoDB table. The developer must grant access to DynamoDB without storing any long-term credentials on the instance. Which approach should the developer use?

Accepted Answer

Use an IAM role and attach it to the EC2 instance profile.. Attaching an IAM role to an EC2 instance profile allows the instance to obtain temporary security credentials from the AWS Security Token Service (STS) via the instance metadata service. This eliminates the need to store long-term credentials on the instance, adhering to the principle of least privilege and improving security posture.

Answer

Store the AWS access key and secret key in a configuration file.

Answer

Use an IAM user and store credentials in AWS Secrets Manager.

Answer

Use the DynamoDB table's resource-based policy to allow the EC2 instance.