DVA-C02 Practice Test 28 — 15 Questions

Question 1

A developer is using AWS CodeCommit as the source repository for a CI/CD pipeline. The developer wants to trigger a build automatically when changes are pushed to a specific branch. Which services can be used to achieve this? (Choose TWO.)

Accepted Answer

AWS CodeBuild. Option A is correct because CodePipeline can be configured with a CodeCommit source action that triggers on changes. Option C is correct because CodeBuild can be triggered directly by CodeCommit via webhooks. Option B is wrong because CloudWatch Events can trigger on CodeCommit events as well, but it is not a build service; however, it can trigger CodeBuild. But the question asks for services that can achieve the trigger, and both CodePipeline and CodeBuild are valid. However, Option D is wrong because CodeDeploy is for deployment, not build. Option E is wrong because CodeStar is a management console, not a trigger service.

Answer

Amazon CloudWatch Events

Answer

AWS CodeStar

Answer

AWS CodeDeploy

Question 2

A developer is designing a microservices architecture where each service runs in its own Amazon ECS container. Services need to communicate with each other. The developer wants to simplify service discovery and load balancing. Which AWS service should the developer use?

Accepted Answer

AWS Cloud Map. Option C is correct because AWS Cloud Map provides service discovery for microservices. Option A is incorrect because Route 53 is for DNS, but not optimized for dynamic service discovery. Option B is incorrect because ELB is for load balancing, not service discovery. Option D is incorrect because Amazon ECS does not have built-in service discovery.

Answer

Elastic Load Balancing

Answer

Amazon ECS service discovery

Answer

Amazon Route 53

Question 3

A developer is reviewing a CloudFormation template that creates an S3 bucket and a Lambda function. The Lambda function's code is stored in the S3 bucket. What is a potential issue with this template?

Accepted Answer

The Lambda function depends on the S3 bucket, but there is no DependsOn clause to ensure the bucket is created first.. Option B is correct because CloudFormation tries to create both resources in parallel, but the Lambda function needs the S3 bucket to exist first to retrieve the code. Additionally, the bucket must have the code uploaded before stack creation. Option A is wrong because the reference is valid. Option C is wrong because versioning is not required. Option D is wrong because the role reference is correct.

Answer

The Lambda function's role is referenced incorrectly; it should be 'Ref' instead of 'GetAtt'.

Answer

The bucket name 'my-unique-bucket-12345' is not globally unique.

Answer

The bucket must have versioning enabled to store Lambda code.

Question 4

Refer to the exhibit. A developer invoked a Lambda function and received the response shown. What does the response indicate?

Accepted Answer

The function was invoked but returned an error.. Option B is correct because the FunctionError field is 'Unhandled' and the response contains an error object, indicating a function error. Option A is wrong because the StatusCode is 200, not 4xx or 5xx. Option C is wrong because the invocation succeeded but the function failed. Option D is wrong because LogResult is empty, but that's not the reason.

Answer

The function was not invoked due to a permissions error.

Answer

The function executed successfully but did not return any logs.

Answer

The invocation timed out.

Question 5

A developer is designing a serverless application that uses Amazon API Gateway and AWS Lambda. The API receives a high volume of requests, and the developer needs to cache responses to reduce latency and cost. Which TWO actions should the developer take? (Choose TWO.)

Accepted Answer

Enable API Gateway caching and set a TTL for the cache.. Option A is correct because enabling caching in API Gateway will cache responses for a specified TTL. Option C is correct because Lambda can return cache-control headers to instruct API Gateway to cache the response. Option B is wrong because CloudFront caches content at the edge, but API Gateway caching is separate and more direct. Option D is wrong because DynamoDB Accelerator is for database caching, not API responses. Option E is wrong because ElastiCache is not integrated with API Gateway for response caching.

Answer

Use DynamoDB Accelerator (DAX) to cache Lambda responses.

Answer

Use ElastiCache for Redis to store frequently accessed responses.

Answer

Use Amazon CloudFront in front of API Gateway to cache responses.

Question 6

Refer to the exhibit. A developer created the CloudFormation template snippet. After deployment, the developer uploads a file to the bucket, but the Lambda function is not invoked. What is the MOST likely cause?

Accepted Answer

The bucket has a bucket policy that denies s3:PutObject for the IAM user.. Option A is correct because S3 bucket policies that deny s3:PutObject would prevent the upload from triggering the event. Option B is wrong because versioning does not affect notifications. Option C is wrong because lifecycle rules do not affect immediate events. Option D is wrong because Lambda function errors do not prevent invocation.

Answer

The bucket has versioning enabled, which blocks event notifications.

Answer

The lifecycle rule moves objects to Glacier before the notification is sent.

Answer

The Lambda function returned an error, so the invocation failed silently.

Question 7

A company uses AWS Elastic Beanstalk to deploy a web application. The application stores user-uploaded images in an S3 bucket. The developer needs to ensure that the application can read and write to the S3 bucket. What should the developer do?

Accepted Answer

Configure the Elastic Beanstalk environment to use an IAM instance profile that grants S3 access.. Option A is correct because Elastic Beanstalk can automatically create and configure an instance profile with the necessary S3 permissions if you specify the bucket policy. Option B is wrong because S3 bucket policies are for bucket-level access, not directly for EC2 instances. Option C is wrong because access keys are insecure. Option D is wrong because CloudFront is for content delivery, not for granting S3 access.

Answer

Use Amazon CloudFront to proxy requests to the S3 bucket.

Answer

Hardcode the AWS access keys in the application code.

Answer

Apply an S3 bucket policy that allows access from the Elastic Beanstalk environment's security group.

Question 8

A company has a REST API deployed on Amazon API Gateway with a Lambda integration. The API is experiencing high latency. Which TWO actions would help diagnose the issue?

Accepted Answer

Use AWS X-Ray to trace requests.. Option B is correct because enabling detailed CloudWatch logs on API Gateway provides per-request metrics and logs. Option C is correct because AWS X-Ray can trace requests through API Gateway and Lambda to identify bottlenecks. Option A is wrong because increasing Lambda memory might reduce latency but does not help diagnose the cause. Option D is wrong because changing the integration type changes the architecture, not diagnose. Option E is wrong because CloudFront is a CDN and would add complexity.

Answer

Increase the Lambda function memory.

Answer

Change the API integration type from Lambda to HTTP.

Answer

Add Amazon CloudFront in front of API Gateway.

Question 9

A developer is using AWS Step Functions to orchestrate a workflow. The developer wants to handle errors and retries for a task. Which TWO fields can be used in a state definition to configure error handling? (Choose TWO.)

Accepted Answer

Retry. Option A is correct because the Retry field specifies retry policies for errors. Option C is correct because the Catch field defines fallback states when a retry is exhausted or not configured. Option B is wrong because ErrorOutput is not a valid field. Option D is wrong because ErrorAction is not a standard field. Option E is wrong because FailureState is not a valid field; the correct field is Catch.

Answer

FailureState

Answer

ErrorOutput

Answer

ErrorAction

Question 10

A developer attached the above IAM policy to an IAM user. The user tries to upload an object to the S3 bucket my-bucket without specifying server-side encryption. What will happen?

Accepted Answer

The upload will be denied because the Deny statement explicitly denies PutObject without AES256 encryption.. Option A is correct because the Deny statement will match (since s3:x-amz-server-side-encryption is not AES256), and explicit Deny overrides Allow. Option B is incorrect because the Allow statement requires encryption, but the Deny explicitly denies if not AES256. Option C is incorrect because the Deny is not redundant; it enforces encryption. Option D is incorrect because the upload will be denied, not proceed without encryption.

Answer

The upload will succeed because the Deny statement is redundant.

Answer

The upload will succeed because the Allow statement grants PutObject permission.

Answer

The upload will succeed but the object will be stored without encryption.

Question 11

A developer is using the AWS CLI to upload a large file to S3. The file is 2 GB. The developer uses the following command: aws s3 cp largefile.zip s3://mybucket/. The upload is taking longer than expected. Which change would MOST improve the upload speed?

Accepted Answer

Increase the multipart upload part size using the --multipart-upload-part-size option.. For large files, the aws s3 cp command automatically uses multipart upload, but increasing the part size can reduce the number of parts and improve throughput. Using aws s3api put-object is single-part and not suitable for large files. Disabling multipart upload would slow it down. S3 Transfer Acceleration reduces latency over long distances, but does not necessarily improve throughput for a single upload.

Answer

Disable multipart upload by setting --no-multipart.

Answer

Enable S3 Transfer Acceleration on the bucket and use the --endpoint-url parameter.

Answer

Use the aws s3api put-object command instead.

Question 12

A developer is writing a Lambda function that processes events from an Amazon Kinesis stream. The function must ensure that records are processed in the order they were received and that each shard is processed by only one instance of the function at a time. How should the developer configure the Lambda function?

Accepted Answer

Set the batch size to 1 and configure the function's reserved concurrency to 1.. Option B is correct because setting the batch size to 1 and the concurrency to the number of shards (or reserved concurrency of 1) ensures per-shard ordering and single-threaded processing per shard. Option A is wrong because parallelization factor processes batches in parallel, breaking ordering. Option C is wrong because Lambda processes multiple shards concurrently by default, but reserving concurrency per shard is not possible; instead, set concurrency to 1. Option D is wrong because Kinesis ordering is per-shard, not across the stream.

Answer

Set the function's concurrency to the number of shards and enable parallelization factor.

Answer

Set the batch size to 100 and enable parallelization factor per shard.

Answer

Use a DynamoDB table to track sequence numbers and enforce ordering.

Question 13

A developer is using the AWS SDK for Python (Boto3) to upload objects to an S3 bucket. The developer wants to encrypt the objects at rest using server-side encryption with AWS KMS managed keys (SSE-KMS). Which parameter should the developer include in the put_object call?

Accepted Answer

ServerSideEncryption: 'aws:kms'. Option C is correct because the ServerSideEncryption parameter set to 'aws:kms' tells S3 to use SSE-KMS. Option A is wrong because SSEAlgorithm is not a valid parameter. Option B is wrong because SSE-S3 uses 'AES256'. Option D is wrong because the key ID is not required if using the default KMS key.

Answer

SSEAlgorithm: 'AES256'

Answer

SSEKMSKeyId: 'alias/aws/s3'

Answer

ServerSideEncryption: 'AES256'

Question 14

A company is using AWS Lambda to process events from an SQS queue. The Lambda function runs for an average of 45 seconds and processes approximately 100 messages per second. The company notices that the Lambda function is being throttled, causing messages to remain in the queue for longer than expected. Which action would MOST effectively reduce throttling?

Accepted Answer

Increase the reserved concurrency for the Lambda function.. Increasing the number of shards for the SQS queue is not applicable because SQS does not use shards. Increasing reserved concurrency for the Lambda function ensures that the function has enough capacity to handle the load without being throttled. Increasing the batch size reduces the number of invocations but does not directly address throttling due to concurrency limits. Using a Dead Letter Queue helps with failed messages but does not prevent throttling.

Answer

Increase the number of shards for the SQS queue.

Answer

Increase the batch size in the Lambda event source mapping.

Answer

Configure a Dead Letter Queue for the SQS queue.

Question 15

A developer is using an Amazon SQS queue with a Lambda function as a consumer. Messages are being sent to the queue but the Lambda function is not processing them. Which THREE of the following are possible causes?

Accepted Answer

The SQS queue policy denies access to the Lambda function.. Option A is correct because the Lambda function may not have permission to poll the queue. Option B is correct because the SQS queue might have a policy that denies access. Option C is correct because the event source mapping might be disabled. Option D is wrong because the DLQ is for failed messages, not for preventing processing. Option E is wrong because SQS has no rate limiting for Lambda polling.

Answer

The SQS queue has a dead-letter queue configured.

Answer

The SQS queue has a rate limit that prevents Lambda from polling.