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

Question 1

A developer is debugging an AWS Lambda function that processes messages from an Amazon SQS queue. The function is failing with an error when processing certain messages. The developer wants to isolate the failed messages for later analysis without losing them. What should the developer do?

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

Accepted Answer

Configure a dead-letter queue (DLQ) for the SQS queue.. Configuring a dead-letter queue (DLQ) for the SQS queue is the correct approach because it automatically captures messages that cannot be processed successfully after a specified number of retries (the redrive policy). This isolates the failed messages for later analysis without losing them, while allowing the function to continue processing other messages from the source queue.

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Publish the failed messages to an SNS topic for later processing.

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Log the error and delete the message from the queue.

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Increase the visibility timeout of the SQS queue.

Question 2

Which TWO AWS services can be used to store and retrieve application configuration data? (Choose two.)

Accepted Answer

AWS AppConfig. AWS AppConfig is a feature of AWS Systems Manager that allows you to create, manage, and deploy application configuration data separately from your code. It supports feature flags, tuning parameters, and other dynamic configuration, and can validate configuration changes before deployment to reduce risk. This makes it a correct choice for storing and retrieving application configuration data.

Answer

AWS Secrets Manager

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Amazon S3

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AWS CloudFormation

Question 3

Which THREE actions can be performed using AWS Lambda and Amazon S3 event notifications? (Choose three.)

Accepted Answer

Resize an image when a new image is uploaded to an S3 bucket.. AWS Lambda can be triggered by S3 event notifications for object creation events. When a new image is uploaded to an S3 bucket, the event notification invokes a Lambda function that can process the image, such as resizing it using libraries like Pillow or Sharp, and save the resized version back to S3.

Answer

Generate a pre-signed URL for an object.

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Enable versioning on the S3 bucket.

Question 4

An IAM policy attached to an IAM user. What is the effect of this policy on the user's ability to delete objects in the bucket my-bucket?

Accepted Answer

The user is denied the ability to delete objects regardless of source IP.. The question cannot be answered as written because the IAM policy text is missing. To determine the effect on s3:DeleteObject, the policy's Effect, Action, and Condition (including any IpAddress or NotIpAddress operators) must be provided. Without the policy, no option can be verified as correct.

Answer

The user can delete objects from any IP address.

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The user can delete objects only if the source IP is not 192.0.2.0/24.

Answer

The user can delete objects only if the source IP is 192.0.2.0/24.

Question 5

A developer wants to store application logs in Amazon S3 with automatic transition to Glacier after 30 days and deletion after 365 days. Which S3 feature should be used?

Accepted Answer

S3 Lifecycle configuration. S3 Lifecycle configuration is the correct feature because it allows you to define rules that automatically transition objects to colder storage classes like Glacier after a specified number of days (30) and permanently delete them after a longer period (365). This directly matches the requirement for time-based storage tiering and deletion without manual intervention.

Answer

S3 Object Lock

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S3 Replication

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S3 Event Notifications

Question 6

A developer is using AWS Lambda with an Amazon RDS MySQL database. The Lambda function frequently times out when connecting to the database. What is the MOST likely cause?

Accepted Answer

The Lambda function is not attached to the same VPC as the RDS instance. Lambda functions must be attached to the same VPC as the RDS instance to connect via a private IP address. Without VPC attachment, the Lambda function attempts to connect over the public internet, which can cause timeouts due to network latency, security group restrictions, or the RDS instance being configured as publicly inaccessible.

Answer

The Lambda function is not configured with enough memory

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The Lambda function is not using a reserved concurrency limit

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The Lambda function's execution role lacks RDS permissions

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?

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

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Use Amazon ElastiCache and modify the Lambda function to check cache

Question 8

A company uses AWS CodeCommit and wants to automatically trigger a build in AWS CodePipeline when code is pushed to the master branch. Which action should be taken?

Accepted Answer

Configure a CloudWatch Events rule to start the pipeline on repository changes. AWS CodePipeline can be configured to automatically start when changes are pushed to a CodeCommit repository by using an Amazon CloudWatch Events rule. The rule listens for CodeCommit repository state changes (e.g., 'ReferenceCreated' or 'ReferenceUpdated' events on the master branch) and targets the pipeline as a CloudWatch Events target, triggering the pipeline execution without polling or manual intervention.

Answer

Add a webhook in CodeCommit to directly invoke CodePipeline

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Set up a scheduled pipeline that polls CodeCommit every minute

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Use an S3 trigger to start the pipeline when code is uploaded

Question 9

A developer needs to securely store database credentials for a Lambda function that accesses an Amazon RDS instance. The credentials must be automatically rotated every 30 days. Which AWS service should be used?

Accepted Answer

AWS Secrets Manager. AWS Secrets Manager is the correct choice because it is specifically designed to securely store, manage, and automatically rotate database credentials for services like Amazon RDS. It supports built-in rotation with a configurable schedule (e.g., every 30 days) using a Lambda rotation function, and it integrates directly with RDS to update credentials without manual intervention. This meets the requirement for automatic rotation and secure storage.

Answer

AWS IAM Roles for Lambda

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AWS Key Management Service (KMS)

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AWS Systems Manager Parameter Store

Question 10

A developer is using AWS Elastic Beanstalk to deploy a web application. The application needs to store session state. Which configuration is MOST cost-effective and scalable?

Accepted Answer

Use an ElastiCache Memcached cluster. ElastiCache Memcached is the most cost-effective and scalable solution for storing session state because it is an in-memory cache designed for low-latency access, which is ideal for session data that must be frequently read and written. It scales horizontally by adding nodes, and its distributed nature ensures that session data persists across EC2 instance replacements, unlike local storage. This avoids the higher cost and overhead of RDS or the latency and eventual consistency issues of S3 for session management.

Answer

Use S3 to store session state

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Use an RDS database to store session state

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Store session state in the local file system of each EC2 instance

Question 11

A developer is building a real-time chat application using Amazon API Gateway WebSockets and AWS Lambda. The developer notices that messages are sometimes delivered out of order. What should the developer do to ensure ordered message delivery?

Accepted Answer

Use an Amazon SQS FIFO queue to buffer messages before processing. WebSocket connections run over TCP, which guarantees in-order delivery of frames from the client to Amazon API Gateway. However, when API Gateway routes these messages to AWS Lambda, Lambda executes concurrently. This concurrent execution can lead to messages being processed, written to a database, or broadcasted to other clients out of order. To guarantee ordered processing, messages can be buffered using an Amazon SQS FIFO (First-In-First-Out) queue before being processed by Lambda, ensuring they are handled in the exact order they were received.

Answer

Increase the Lambda function's memory allocation

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Use API Gateway's built-in message ordering feature

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Set the 'sequenceNumber' property in the WebSocket message

Question 12

Which TWO actions should a developer take to improve the security of an AWS Lambda function that processes sensitive data?

Accepted Answer

Encrypt environment variables using AWS KMS. Encrypting environment variables with AWS KMS ensures that sensitive data, such as database credentials or API keys, is protected at rest and in transit during function deployment. This is a critical security best practice because environment variables are visible in plaintext in the Lambda console and API responses unless encrypted. KMS provides envelope encryption, where a customer master key (CMK) encrypts the data key that encrypts the environment variables, giving you full control over access and key rotation.

Answer

Use a dead-letter queue (DLQ) for failed invocations

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Grant the Lambda function full access to all S3 buckets

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Store secrets in the Lambda function code

Question 13

A developer is designing a serverless application that uses Amazon DynamoDB as the data store. The application must handle sudden spikes in read traffic without throttling. Which THREE actions should the developer take?

Accepted Answer

Configure DynamoDB auto scaling for the table. DynamoDB auto scaling (option A) dynamically adjusts the provisioned read and write capacity based on actual traffic patterns, using CloudWatch alarms and the Application Auto Scaling service. This ensures the table can handle sudden spikes in read traffic without manual intervention, preventing throttling exceptions.

Answer

Use a global secondary index with a different partition key

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Use strongly consistent reads for all queries

Question 14

Which TWO of the following are valid use cases for Amazon S3 event notifications?

Accepted Answer

Send a notification to an SQS queue when a new object is created. Amazon S3 event notifications can be configured to publish events to an SQS queue when a new object is created (s3:ObjectCreated:*). This allows decoupled, asynchronous processing of object creation events without polling, making it ideal for workflows like log aggregation or data ingestion pipelines.

Answer

Automatically replicate objects to another bucket

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Automatically delete objects after 30 days

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Encrypt objects automatically with KMS

Question 15

The exhibit shows the output of a command. What does this output indicate about the bucket?

Accepted Answer

Versioning is enabled, and MFA delete is not required. The command output shows `MFA Delete: disabled` and `Versioning: Enabled`. This directly indicates that versioning is enabled on the bucket, but MFA delete is not required. Option D is correct because it matches both displayed fields exactly.

Answer

Versioning is enabled, and MFA delete is required

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Versioning is suspended

Answer

Versioning is disabled