DVA-C02 Development with AWS Services Practice Test 23 — 15 Questions

Question 1

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 2

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 3

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 4

A company has a Node.js application running on an EC2 instance. The application needs to store session state. The developer wants to ensure high availability and scalability by storing session data externally. Which AWS service is BEST suited for this purpose?

Accepted Answer

Amazon ElastiCache for Redis. Option B is correct because ElastiCache for Redis provides an in-memory data store that is ideal for session management, offering low latency and high throughput. Option A is wrong because S3 is for object storage, not low-latency session storage. Option C is wrong because RDS is a relational database, which is slower for session data. Option D is wrong because DynamoDB is a NoSQL database but is not as fast as in-memory caching for session state.

Answer

Amazon DynamoDB

Answer

Amazon S3

Answer

Amazon RDS for MySQL

Question 5

A developer is deploying a microservices architecture on Amazon ECS using Fargate launch type. The services need to communicate with each other. The developer wants to use service discovery so that services can find each other by name. Which AWS service should the developer use?

Accepted Answer

AWS Cloud Map. Option B is correct because AWS Cloud Map is a service discovery service that allows you to register and discover services by name. Option A is wrong because Route 53 is for DNS resolution but not designed for dynamic service discovery in ECS. Option C is wrong because ELB is for load balancing, not service discovery. Option D is wrong because ECR is a container registry.

Answer

Amazon Route 53 private hosted zones

Answer

Amazon ECR

Answer

Application Load Balancer

Question 6

The developer runs a scan on the DynamoDB table 'orders' with a filter expression to find items with order_status equal to 'SHIPPED'. The output shows ScannedCount of 10000 but Count of 0. Which statement is correct?

Accepted Answer

The scan retrieved 10,000 items from the table, but none matched the filter condition.. Option A is correct because filter expressions are applied after the scan retrieves the items, so all 10,000 items were scanned but none matched the filter. Option B is wrong because the scan returns up to 1 MB of data, not a fixed number of items, and the filter is applied after. Option C is wrong because the filter expression is syntactically correct. Option D is wrong because the filter expression is applied after scanning, not before.

Answer

The scan only returned items that matched the filter, so there are no items with status SHIPPED.

Answer

The filter expression syntax is incorrect, causing the scan to return zero items.

Answer

The scan applied the filter before reading items, so only matching items were scanned.

Question 7

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 8

A developer attaches this IAM policy to an IAM user. The user tries to upload an object to the S3 bucket my-bucket from an IP address of 10.0.1.5. What will happen?

Accepted Answer

The upload will fail because the IP address is not within the allowed range.. Option D is correct because the condition restricts access to the IP range 10.0.0.0/24. The user's IP 10.0.1.5 is outside that range, so the request will be denied. Option A is wrong because even though the action is allowed, the condition denies it. Option B is wrong because the condition is evaluated and denies the request. Option C is wrong because the condition is valid.

Answer

The upload will fail because the bucket policy denies access.

Answer

The upload will succeed because the policy allows s3:PutObject.

Answer

The upload will succeed because the condition is ignored for uploads.

Question 9

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 10

A company is deploying a containerized application on Amazon ECS using the Fargate launch type. The application must be highly available across multiple Availability Zones. The developer needs to configure the ECS service. Which THREE configuration options are required? (Choose THREE.)

Accepted Answer

Set the desired number of tasks to at least 2.. Option A is correct because a load balancer is needed to distribute traffic across tasks in multiple AZs. Option C is correct because setting the number of tasks to at least 2 ensures redundancy. Option D is correct because spreading tasks across multiple AZs ensures high availability. Option B is wrong because ECS does not support Auto Scaling groups with Fargate. Option E is wrong because a DynamoDB table is not needed for ECS service configuration.

Answer

Create an Auto Scaling group for the Fargate tasks.

Answer

Use a DynamoDB table to store task state.

Question 11

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 12

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 13

A developer is building a REST API using API Gateway and Lambda. The API must support multiple HTTP methods and use a custom domain name with an SSL certificate. The developer wants to enable caching for the /products GET endpoint to reduce latency. Which step is essential to enable caching for this specific endpoint?

Accepted Answer

Enable caching on the /products GET method and specify cache key parameters.. Caching is enabled at the stage level, but can be overridden per method by enabling caching on the method and setting the cache key parameters. Enabling caching on the stage without configuring the method does not cache responses for that method unless the method inherits. Setting TTL is not the essential step. Flush cache is for clearing, not enabling.

Answer

Set the TTL (time-to-live) for the /products GET method to a non-zero value.

Answer

Flush the API cache to start fresh.

Answer

Enable caching on the API stage and set the 'Cache Status' to 'AVAILABLE'.

Question 14

A company stores sensitive user data in an S3 bucket. The security team requires that all data be encrypted at rest using a customer-managed KMS key. The bucket already has default encryption configured with SSE-S3. What is the MINIMUM change needed to meet the requirement?

Accepted Answer

Change the default encryption of the bucket to SSE-KMS with the desired KMS key.. SSE-S3 is Amazon-managed keys, not customer-managed. To use customer-managed KMS keys, you must change the default encryption to SSE-KMS. S3 Bucket Keys reduce KMS costs but are not required. Object-level encryption settings are not needed if default encryption is set. Policy change is not sufficient.

Answer

Add an object-level encryption setting to each object after upload.

Answer

Enable S3 Bucket Keys on the bucket.

Answer

Attach a bucket policy that denies uploads without the required KMS key.

Question 15

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.