DVA-C02 Development with AWS Services Practice Test 16 — 15 Questions

Question 1

A developer is designing a serverless application that uses AWS Lambda and Amazon DynamoDB. The application needs to handle high traffic spikes without data loss. Which TWO actions should the developer take?

Accepted Answer

Enable DynamoDB Auto Scaling. Option B is correct because SQS decouples processing and provides a buffer. Option D is correct because DynamoDB auto scaling handles capacity. Option A is wrong because Lambda concurrency limit would throttle. Option C is not directly related. Option E is wrong because Provisioned IOPS is for EBS.

Answer

Use Provisioned IOPS for DynamoDB

Answer

Enable DynamoDB Streams

Answer

Increase the Lambda concurrency limit to the maximum

Question 2

A company is using AWS CodePipeline to automate its CI/CD pipeline. The pipeline has a source stage that pulls code from an Amazon S3 bucket. Which THREE steps should the developer take to ensure that only approved changes are deployed to production?

Accepted Answer

Use AWS CloudFormation change sets to review changes. Option A is correct because manual approval gates allow review. Option B is correct because S3 versioning enables rollback. Option D is correct because CloudFormation change sets allow preview. Option C is wrong because AWS KMS is not needed. Option E is wrong because cross-account access is not mentioned.

Answer

Configure cross-account access for the pipeline

Answer

Encrypt the S3 bucket with AWS KMS

Question 3

A developer needs to monitor the performance of an Amazon RDS for MySQL database. Which TWO metrics should the developer monitor to detect a potential CPU bottleneck?

Accepted Answer

DatabaseConnections. Option B is correct because CPUUtilization directly shows CPU usage. Option D is correct because DatabaseConnections can indicate high load causing CPU contention. Option A is wrong because FreeStorageSpace is storage. Option C is wrong because ReadLatency is I/O. Option E is wrong because NetworkThroughput is network.

Answer

FreeStorageSpace

Answer

NetworkThroughput

Answer

ReadLatency

Question 4

Refer to the exhibit. An IAM policy is attached to an IAM user. The user tries to upload an object to s3://my-bucket/confidential/report.pdf. What is the outcome?

Accepted Answer

The upload fails because the Deny statement explicitly denies access to the confidential prefix.. Option B is correct because the Deny statement explicitly denies all s3 actions on the confidential prefix, and explicit Deny overrides any Allow. Option A is wrong because the Deny overrides the Allow. Option C is wrong because there is no explicit Allow for that prefix. Option D is wrong because the policy applies.

Answer

The upload succeeds because the Allow statement grants s3:PutObject on the bucket.

Answer

The upload fails because there is no Allow statement for the confidential prefix.

Answer

The upload fails because the policy is malformed.

Question 5

Refer to the exhibit. A developer ran the AWS CLI command to invoke a Lambda function. The response indicates an error. What should the developer do to see the error details?

Accepted Answer

Decode the LogResult value from base64 to see the logs.. Option A is correct because the LogResult contains base64-encoded logs. Option B is wrong because the logs are not automatically in CloudWatch. Option C is wrong because the LogResult is base64, not plain text. Option D is wrong because the error is Unhandled, not a timeout.

Answer

Check CloudWatch Logs for the function's log group.

Answer

Increase the Lambda function timeout to avoid the error.

Answer

Read the output.txt file for the error message.

Question 6

Refer to the exhibit. A developer created this CloudFormation template for an S3 bucket. What is the expected behavior?

Accepted Answer

Noncurrent versions of objects are deleted 30 days after they become noncurrent.. Option B is correct because the lifecycle rule will delete noncurrent versions after 30 days. Option A is wrong because versioning is enabled, so old versions are kept. Option C is wrong because the rule only applies to noncurrent versions. Option D is wrong because the action is expiration, not transition.

Answer

The bucket will have versioning disabled because the rule conflicts.

Answer

Current versions are transitioned to another storage class after 30 days.

Answer

Objects are automatically deleted after 30 days.

Question 7

A company has a Lambda function that processes records from an SQS queue. The function is failing intermittently with timeout errors. The processing time per record varies, but the SQS queue has a visibility timeout of 30 seconds. The Lambda function has a timeout of 1 minute. What is the MOST likely cause of the timeout errors?

Accepted Answer

The SQS visibility timeout is shorter than the Lambda function timeout.. Option B is correct because the Lambda function's maximum execution time is 15 minutes, but the SQS visibility timeout of 30 seconds is shorter than the Lambda timeout of 1 minute. If the Lambda function takes longer than 30 seconds, the message becomes visible again and another Lambda invocation may process it, causing duplicate processing and potential timeouts. Option A is incorrect because Lambda can scale to handle many messages. Option C is irrelevant because batch size affects concurrency but not individual function timeout. Option D is incorrect because 30 seconds is a typical visibility timeout.

Answer

The Lambda function's reserved concurrency is set too low.

Answer

The SQS queue has too many messages causing Lambda to throttle.

Answer

The SQS queue's default visibility timeout of 30 seconds is too long.

Question 8

A developer is building a serverless application using AWS Lambda and Amazon DynamoDB. The Lambda function needs to read and write items to a DynamoDB table. What is the BEST way to securely provide the Lambda function with the necessary AWS credentials?

Accepted Answer

Create an IAM role with DynamoDB permissions and attach it to the Lambda function.. Option C is correct because the best practice is to attach an IAM role to the Lambda function with the required permissions. This avoids hardcoding credentials. Option A is incorrect because storing credentials in environment variables is not secure. Option B is incorrect because Lambda does not use access keys in IAM users; it uses roles. Option D is incorrect because the Lambda function should have least privilege, not full admin access.

Answer

Store the AWS access key and secret key in the Lambda environment variables.

Answer

Create an IAM user with programmatic access and store the credentials in the Lambda code.

Answer

Use the Lambda function's default full admin access provided by AWS.

Question 9

A company is using AWS CodeDeploy to deploy an application to an Auto Scaling group. The deployment fails with the error 'The overall deployment failed because too many individual instances failed to deploy.' The CodeDeploy agent logs show that the BeforeInstall lifecycle event script returned a non-zero exit code. What is the MOST likely cause of this issue?

Accepted Answer

The BeforeInstall script has a bug that causes it to exit with a non-zero status.. Option A is correct because a non-zero exit code from a lifecycle event script causes the deployment to fail on that instance. Option B is incorrect because if the agent were not running, the deployment would not even start. Option C is incorrect because a missing application revision would cause a different error. Option D is incorrect because IAM permissions issues would prevent the agent from downloading the revision, not cause a script to fail.

Answer

The application revision is missing from the S3 bucket.

Answer

The IAM instance profile does not have permissions to call CodeDeploy APIs.

Answer

The CodeDeploy agent is not running on the instances.

Question 10

A developer is writing a Lambda function that processes events from an Amazon S3 bucket. The function needs to access a DynamoDB table to store metadata about the S3 objects. Which of the following is the MOST efficient way to initialize the DynamoDB client in the Lambda function?

Accepted Answer

Create the DynamoDB client outside the Lambda handler function, in the global scope.. Option B is correct because initializing the DynamoDB client outside the handler allows it to be reused across invocations, improving performance. Option A is incorrect because creating a new client for each invocation adds overhead. Option C is incorrect because using a global variable for the table name is fine, but the client should be initialized outside. Option D is incorrect because using a static variable in Java achieves the same effect as initializing outside the handler.

Answer

Store the DynamoDB table name as a global variable and create the client inside the handler.

Answer

Use a static variable inside the handler to cache the DynamoDB client.

Answer

Create the DynamoDB client inside the Lambda handler function every invocation.

Question 11

A developer needs to store application configuration data, such as database connection strings and API keys, for a microservices application running on Amazon ECS. The configuration must be encrypted at rest and easily auditable. Which AWS service should the developer use?

Accepted Answer

AWS Systems Manager Parameter Store.. Option C is correct because AWS Systems Manager Parameter Store can store configuration data securely, with encryption using KMS, and provides audit trails via CloudTrail. Option A is incorrect because S3 is not designed for parameter storage and would require additional setup for encryption and access control. Option B is incorrect because DynamoDB is a database, not a configuration store; it would require more overhead. Option D is incorrect because Secrets Manager is more expensive and is specifically for secrets, not general application configuration.

Answer

AWS Secrets Manager.

Answer

Amazon S3 with server-side encryption.

Answer

Amazon DynamoDB with encryption at rest.

Question 12

A company runs a stateful web application on EC2 instances behind an Application Load Balancer. The application uses WebSockets for real-time communication. The company wants to use AWS CodeDeploy to deploy updates with minimal downtime. Which deployment configuration should the developer use?

Accepted Answer

Blue/green deployment.. Option A is correct because a blue/green deployment allows the company to create a new set of instances (green) and switch traffic after testing, minimizing downtime. Option B is incorrect because in-place deployment would update instances one by one, but stateful applications may lose session data. Option C is incorrect because immutable deployments are not supported by CodeDeploy for EC2; they are used with Elastic Beanstalk. Option D is incorrect because canary deployments are for Lambda, not EC2.

Answer

Canary deployment.

Answer

In-place deployment.

Answer

Immutable deployment.

Question 13

A developer is using Amazon API Gateway to expose a Lambda function as a REST API. The Lambda function queries an Amazon RDS database. Under heavy load, the database connection pool is exhausted, causing errors. What is the BEST way to manage database connections in this serverless architecture?

Accepted Answer

Use Amazon RDS Proxy to pool and share database connections.. Option D is correct because RDS Proxy is designed to manage database connection pooling for serverless applications, reducing connection exhaustion. Option A is incorrect because increasing Lambda concurrency would make the problem worse. Option B is incorrect because storing connections in ElastiCache does not help with database connections. Option C is incorrect because using DynamoDB would change the database, not solve the connection management issue.

Answer

Migrate the database to Amazon DynamoDB.

Answer

Increase the concurrency limit of the Lambda function.

Answer

Use Amazon ElastiCache to cache database connections.

Question 14

A developer is building a CI/CD pipeline using AWS CodePipeline. The source stage is an Amazon S3 bucket. The developer wants to automatically start the pipeline when a new file is uploaded to the S3 bucket. What should the developer do?

Accepted Answer

Create an Amazon CloudWatch Events rule that triggers on S3 object creation events and targets the pipeline.. Option B is correct because CodePipeline can be configured to use Amazon CloudWatch Events (now Amazon EventBridge) to detect S3 events and start the pipeline. Option A is incorrect because SQS does not trigger CodePipeline. Option C is incorrect because SNS can be used but is not a direct trigger; EventBridge is the recommended approach. Option D is incorrect because polling is not efficient; EventBridge provides real-time events.

Answer

Configure the S3 bucket to send events to an SQS queue, and poll the queue from CodePipeline.

Answer

Set up a periodic Lambda function that checks the S3 bucket for new files and starts the pipeline.

Answer

Configure the S3 bucket to send events to an SNS topic, and subscribe CodePipeline to the topic.

Question 15

A developer is designing a serverless application that processes user-uploaded images. The images are uploaded to an S3 bucket, which triggers a Lambda function to create a thumbnail and store metadata in DynamoDB. The thumbnail creation is CPU-intensive and can take up to 10 seconds. The developer wants to minimize costs and ensure that the thumbnail is created as soon as possible. Which approach should the developer choose?

Accepted Answer

Use S3 event notifications to directly invoke the Lambda function.. Option C is correct because Lambda can handle CPU-intensive tasks, and using the S3 event to directly trigger Lambda is the simplest and most cost-effective approach. Option A is incorrect because Step Functions add cost and complexity. Option B is incorrect because SQS introduces latency and cost. Option D is incorrect because ECS requires provisioning and management, increasing complexity and cost compared to Lambda.

Answer

Use AWS Step Functions to orchestrate the Lambda function and DynamoDB update.

Answer

Use an ECS Fargate task to process the images, triggered by S3 events.

Answer

Use an SQS queue between S3 and Lambda to buffer requests.