DVA-C02 Development with AWS Services Practice Test 32 — 15 Questions

Question 1

A company is using AWS CloudFormation to deploy infrastructure. The developer needs to update a stack but wants to avoid downtime for a critical database. Which THREE strategies should the developer consider?

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

Accepted Answer

Use the UpdateReplace policy to create a new resource before deleting the old one.. The `UpdateReplace` policy (specifically using a `CreationPolicy` and `UpdatePolicy` with `AutoScalingReplacingUpdate`) instructs CloudFormation to create a replacement resource before deleting the original, ensuring zero downtime during a stack update that requires resource replacement. This is critical for a database where continuous availability is required.

Answer

Set the DeletionPolicy attribute to Retain on the database resource.

Answer

Use the Parameters section to set a conditional update flag.

Question 2

A developer attaches the IAM policy shown to a user. The user attempts to upload an object to example-bucket using the AWS CLI with the command: `aws s3 cp file.txt s3://example-bucket/`. The upload fails. What is the MOST likely reason?

Accepted Answer

The user did not specify server-side encryption in the request.. The IAM policy shown (not provided in the question but implied by the context) likely includes a condition that requires server-side encryption (e.g., `s3:x-amz-server-side-encryption: AES256`). The `aws s3 cp` command by default does not set the `--sse` flag, so the request lacks the required encryption header, causing S3 to deny the upload with an AccessDenied error.

Answer

The user does not have permission to perform s3:PutObject on the bucket.

Answer

The bucket policy overrides the IAM policy and denies the request.

Answer

The resource ARN does not include the bucket itself.

Question 3

A developer runs the AWS CLI command shown. The Lambda function returns a 200 status code but the output file is null and the response includes FunctionError: Unhandled. What does this indicate?

Accepted Answer

The Lambda function threw an unhandled exception.. The presence of `FunctionError: Unhandled` in the response of an `aws lambda invoke` command indicates that the Lambda function encountered an error (such as an unhandled exception or runtime crash) that was not caught by the function's code. Even though the function failed, the Invoke API itself successfully completed the transaction of invoking the function, which is why it returns an HTTP status code of 200.

Answer

The Lambda function timed out.

Answer

The payload was too large for synchronous invocation.

Answer

The Lambda function was not found.

Question 4

A developer creates an AWS CloudFormation stack with the template snippet shown. The stack creation fails with the error: "Bucket with name my-unique-bucket-12345 already exists." What is the MOST likely cause?

Accepted Answer

The bucket name is already taken by another AWS account.. The error message 'Bucket with name my-unique-bucket-12345 already exists' indicates that the bucket name is globally unique across all AWS accounts. Since the bucket name is already taken, the most likely cause is that another AWS account has already created a bucket with that exact name. S3 bucket names are unique across all of AWS, not just within a single account or region.

Answer

The developer does not have permission to create S3 buckets.

Answer

The CloudFormation template has a syntax error.

Answer

The bucket name was used by another stack in the same account.

Question 5

A developer wants to store session state for a web application that runs on multiple EC2 instances behind an Application Load Balancer. Which AWS service should the developer use to store the session state in a centralized, highly available location?

Accepted Answer

Amazon ElastiCache. Amazon ElastiCache is the correct choice because it provides a managed, in-memory caching service that supports Redis or Memcached, which are ideal for storing session state in a centralized, highly available manner. Session data requires low-latency reads and writes, and ElastiCache offers sub-millisecond performance, replication across multiple Availability Zones, and automatic failover, making it suitable for stateless web applications behind an Application Load Balancer.

Answer

Amazon RDS

Answer

Amazon S3

Answer

AWS Lambda

Question 6

A company is developing a serverless application using AWS Lambda and API Gateway. The application needs to process user uploads to Amazon S3. The Lambda function must be invoked asynchronously after an object is uploaded to an S3 bucket. Which configuration should the developer use to invoke the Lambda function?

Accepted Answer

Configure the S3 bucket to send events to Lambda by adding a Lambda trigger in the S3 bucket properties.. S3 can directly invoke Lambda asynchronously via a bucket notification configuration. When an object is uploaded, S3 publishes an event to the Lambda service, which then executes the function without requiring any intermediary services. This is the simplest and most direct way to trigger a Lambda function from an S3 event.

Answer

Configure the S3 bucket to send events to an Amazon SQS queue and have Lambda poll the queue.

Answer

Configure the S3 bucket to send events to Amazon CloudWatch Events and have CloudWatch invoke Lambda.

Answer

Configure the S3 bucket to send events to an Amazon API Gateway endpoint that triggers the Lambda function.

Question 7

A developer is deploying a microservices application using Amazon ECS with Fargate. The application consists of multiple services that need to communicate with each other over HTTP. The developer wants to ensure that service-to-service communication is encrypted in transit and that the services can discover each other by logical service names instead of IP addresses. Which combination of AWS services should the developer use?

Accepted Answer

AWS App Mesh with AWS Cloud Map. AWS App Mesh provides a service mesh that handles service-to-service communication with encryption in transit using TLS, while AWS Cloud Map enables service discovery by logical names, allowing ECS services to resolve each other via DNS or API calls. Together, they meet the requirements for encrypted HTTP communication and logical name resolution without exposing IP addresses.

Answer

Elastic Load Balancing with AWS Systems Manager

Answer

Amazon Route 53 with AWS Direct Connect

Answer

AWS Lambda with Amazon API Gateway

Question 8

A developer has written an AWS Lambda function that processes messages from an Amazon SQS queue. The function is configured with a reserved concurrency of 5. The SQS queue has 10,000 messages waiting to be processed. What will happen when the Lambda function is invoked?

Accepted Answer

Lambda will process messages with a maximum of 5 concurrent executions, each processing a batch of messages.. AWS Lambda integrates with Amazon SQS to poll the queue and invoke the function with batches of messages. The reserved concurrency of 5 caps the maximum number of concurrent executions, so Lambda will process messages with up to 5 concurrent invocations, each receiving a batch of up to 10 messages (default batch size). The remaining messages remain in the queue until they are processed or the visibility timeout expires.

Answer

Lambda will automatically increase reserved concurrency to handle the load.

Answer

Lambda will reject the invocation because reserved concurrency is too low.

Answer

Lambda will scale up to 20 concurrent executions to process all messages quickly.

Question 9

A company is using AWS CodePipeline to automate its CI/CD pipeline. The pipeline has a build stage that uses AWS CodeBuild. The developer wants to run unit tests and only proceed to the deploy stage if the tests pass. Which configuration should the developer use to achieve this?

Accepted Answer

Configure the build stage to run tests and fail the build if tests fail; CodePipeline will automatically stop.. AWS CodeBuild can be configured to run unit tests as part of the build phase. If any test fails, CodeBuild exits with a non-zero status, causing the build to fail. CodePipeline automatically stops the pipeline execution when a stage fails, preventing the deploy stage from running. This is the native and simplest way to gate deployment on test success.

Answer

Configure a manual approval step before the deploy stage.

Answer

Configure Amazon CloudWatch alarms to stop the pipeline if tests fail.

Answer

Configure AWS Lambda to invoke a function that checks test results and manually stops the pipeline.

Question 10

A development team is building a real-time chat application using Amazon API Gateway WebSocket APIs and AWS Lambda. The application needs to maintain a connection to each user and broadcast messages to all connected clients. Which approach should the developer use to scale the application efficiently?

Accepted Answer

Store connection IDs in Amazon DynamoDB and use the API Gateway Management API to send messages to all connections.. DynamoDB provides a scalable, serverless key-value store to persist WebSocket connection IDs, and the API Gateway Management API allows Lambda to send messages directly to any connected client via its connection ID. This combination efficiently handles the broadcast requirement without managing infrastructure, as Lambda can iterate over stored connection IDs and call the Management API for each message.

Answer

Use Amazon ElastiCache to cache connection IDs and have Lambda send messages using the Redis pub/sub feature.

Answer

Use Amazon SNS to publish messages to all connected clients via the WebSocket API.

Answer

Use Amazon SQS to queue messages and have Lambda poll the queue to send messages to all connections.

Question 11

A developer is using AWS SAM to define a serverless application. The application includes an AWS Lambda function that needs to access an Amazon DynamoDB table. The developer wants to grant the Lambda function the minimum required permissions to read and write items in the table. Which resource should the developer use to define the IAM permissions?

Accepted Answer

AWS::Serverless::Function Policies property. The AWS::Serverless::Function resource's Policies property allows you to attach IAM policies directly to the Lambda function's execution role in a declarative manner. By specifying a policy statement with dynamodb:GetItem, dynamodb:PutItem, etc., and the ARN of the DynamoDB table, you grant the minimum required permissions for read and write access without manually creating an IAM role. SAM automatically creates and associates the IAM role with the function, simplifying permission management.

Answer

AWS::DynamoDB::Table

Answer

AWS::IAM::Role

Answer

AWS::Lambda::Permission

Question 12

A company runs a batch processing job on Amazon ECS using Fargate. The job processes files from an S3 bucket and writes results to another S3 bucket. The job runs once per day and takes about 30 minutes. The company wants to reduce costs by stopping the ECS service when not in use. Which solution should the developer implement?

Accepted Answer

Use AWS Batch with a Fargate launch type and schedule the job with Amazon EventBridge.. AWS Batch with a Fargate launch type is the ideal solution because it is purpose-built for batch processing jobs that run to completion. By scheduling the job with Amazon EventBridge, you can trigger the job once per day, and AWS Batch automatically provisions the Fargate compute environment only when the job runs, then scales down to zero after completion—eliminating costs during idle periods. This approach directly addresses the requirement to reduce costs by stopping the ECS service when not in use, without manual intervention.

Answer

Use an AWS Lambda function to run the job and configure a scheduled event in Amazon EventBridge.

Answer

Use Amazon ECS Service Auto Scaling to scale the service down to zero tasks when not in use.

Answer

Use an Amazon EC2 Auto Scaling group to launch an instance, run the job, and then terminate.

Question 13

A developer is deploying a web application on Amazon EKS. The application needs to read configuration data from an Amazon S3 bucket at startup. The developer wants to ensure that the configuration is securely accessed without embedding AWS credentials in the application code. Which solution should the developer use?

Accepted Answer

Use IAM roles for service accounts (IRSA) to assign an IAM role to the pod.. IAM roles for service accounts (IRSA) allows you to associate an IAM role with a Kubernetes service account, which the pod can assume to obtain temporary AWS credentials via the AWS STS endpoint. This eliminates the need to embed long-term credentials in the application code or environment variables, and the credentials are automatically rotated by the AWS SDK. The pod retrieves the configuration from S3 using the assumed role's permissions, ensuring secure access.

Answer

Store the AWS credentials in AWS Secrets Manager and retrieve them at startup.

Answer

Assign an IAM instance profile to the EC2 instances running the EKS nodes.

Answer

Embed the AWS access key and secret key in a Kubernetes ConfigMap.

Question 14

Which THREE AWS services are commonly used together to build a serverless event-driven architecture that processes real-time streaming data? (Choose three.)

Accepted Answer

Amazon Kinesis Data Streams. Amazon Kinesis Data Streams (A) is correct because it ingests and buffers real-time streaming data at scale, serving as the event source for downstream serverless processing. AWS Lambda (B) is correct because it provides serverless compute that can be triggered by Kinesis stream records via event source mappings, enabling event-driven processing without managing servers. Amazon DynamoDB (C) is correct because it is a fully managed, serverless NoSQL database commonly used as the sink to store processed streaming results, and DynamoDB Streams can further propagate events. Amazon SQS (D) is not selected because it is a message queue for decoupling components, not a real-time streaming data service, and it is not one of the three services typically combined for streaming ingestion and processing in this scenario. Amazon Redshift (E) is not selected because it is a data warehouse designed for analytical queries on batch-loaded data, not for real-time serverless stream processing.

Answer

Amazon SQS

Answer

Amazon Redshift

Question 15

Which TWO AWS services can be used to deploy and manage containerized applications? (Choose two.)

Accepted Answer

Amazon ECS. Amazon ECS (Elastic Container Service) is a fully managed container orchestration service that allows you to run Docker containers at scale. It integrates with AWS Fargate for serverless compute or EC2 for more control, and it handles cluster management, scheduling, and scaling of containerized applications.

Answer

Amazon EC2

Answer

Amazon RDS

Answer

AWS Lambda