DVA-C02 Practice Test 29 — 15 Questions

Question 1

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 2

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 3

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 4

Refer to the exhibit. A developer runs the AWS CLI command to invoke a Lambda function asynchronously. What does the response indicate?

Accepted Answer

The function invocation was accepted but the function failed to execute successfully.. Correct: D. The StatusCode 202 indicates the invocation was accepted. However, the FunctionError set to 'Unhandled' means the function invocation failed and the error was not handled by the function's error handling (e.g., a caught exception or DLQ). Option A is wrong because 202 does not mean success. Option B is wrong because 202 means accepted, not denied. Option C is wrong because the invocation type is Event (async), not synchronous.

Answer

The function executed successfully and returned output.

Answer

The invocation was denied due to insufficient permissions.

Answer

The function was invoked synchronously and returned an error.

Question 5

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 6

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 7

A developer is writing a Lambda function that processes records from a Kinesis stream. The function must handle duplicate records and ensure exactly-once processing. Which approach should the developer use?

Accepted Answer

Use a unique identifier for each record and store processed IDs in a DynamoDB table to skip duplicates.. Kinesis does not guarantee exactly-once delivery; the application must handle duplicates. Using a unique identifier to deduplicate in a DynamoDB table ensures idempotency. Enabling record ordering does not prevent duplicates. Using a FIFO queue is not applicable for Kinesis. Disabling retries would lose data.

Answer

Disable retries in the Lambda function to avoid processing duplicates.

Answer

Enable record ordering in the Kinesis stream.

Answer

Send the records to an SQS FIFO queue for deduplication.

Question 8

A company has a DynamoDB table that stores order data. The table has a partition key of OrderID and a sort key of OrderDate. The company frequently queries orders by CustomerID, which is not a key attribute. The queries are slow and consume a lot of read capacity. Which design change would MOST improve query performance?

Accepted Answer

Create a Global Secondary Index (GSI) with CustomerID as the partition key.. Queries by non-key attributes require a Scan, which is inefficient. Creating a Global Secondary Index with CustomerID as the partition key allows efficient querying. Changing the table's key would break existing applications. Using FilterExpression still scans the table. Increasing read capacity only addresses throttling, not performance of scans.

Answer

Increase the provisioned read capacity for the table.

Answer

Change the table's primary key to use CustomerID as the partition key.

Answer

Use a FilterExpression on the CustomerID attribute in a Scan operation.

Question 9

A developer is deploying an application using AWS CloudFormation. The template includes an AWS::Lambda::Function resource. The developer wants to ensure that the Lambda function's code is automatically updated when the source code in S3 changes. Which approach should the developer use?

Accepted Answer

Specify the S3 object version in the template and update the version number in the template when code changes.. CloudFormation does not automatically detect changes in S3. Using the same S3 key with a version ID ensures that CloudFormation sees a change and updates the function. Using a parameter for the bucket does not trigger updates. Custom Resource or CodePipeline is overkill for simple updates.

Answer

Use the AWS::Lambda::Version resource to create a new version.

Answer

Include the S3 bucket and key as template parameters and update the stack with a new key when code changes.

Answer

Use a custom resource backed by a Lambda function that polls S3 for changes.

Question 10

A developer is deploying a new version of an AWS Lambda function. The deployment failed because the new function code references a layer that is not available. Which AWS CLI command can be used to list all layers associated with the function?

Accepted Answer

aws lambda get-function-configuration --function-name my-function. Option C is correct because `aws lambda get-function-configuration` returns the function's configuration, including Layers. Option A is wrong because `list-layers` lists all layers in the account, not those attached to a specific function. Option B is wrong because `list-layer-versions` lists versions of a specific layer. Option D is wrong because `get-function` returns the function code but does not include layers by default.

Answer

aws lambda list-layer-versions --layer-name my-layer

Answer

aws lambda get-function --function-name my-function

Answer

aws lambda list-layers --function-name my-function

Question 11

A developer is troubleshooting an AWS Lambda function that times out when processing large files from Amazon S3. The function has a 15-minute timeout and 512 MB memory. What should the developer do to resolve this issue?

Accepted Answer

Increase the Lambda function memory to 3008 MB.. Option C is correct because increasing memory also increases CPU and network throughput, which can reduce execution time. Option A is wrong because Lambda already supports up to 15 minutes. Option B is wrong because increasing memory is a more direct solution than splitting files. Option D is wrong because S3 Event Notifications are configured, not something to add to solve timeout.

Answer

Use Amazon S3 batch operations to split the files before processing.

Answer

Add an S3 Event Notification to trigger the function asynchronously.

Answer

Reduce the Lambda timeout to 5 minutes to force faster processing.

Question 12

A company is using AWS CodePipeline to automate deployments. The pipeline has a source stage that retrieves code from an S3 bucket, a build stage using CodeBuild, and a deploy stage using CodeDeploy. The build stage sometimes fails due to intermittent network issues. Which TWO actions would make the pipeline more resilient to such failures?

Accepted Answer

Enable retry on the build stage to automatically attempt the build again on failure.. Enabling retry on the build stage allows the pipeline to automatically retry on failure. Configuring a manual approval stage does not help with automated retries. Using a different source does not address build failures. Splitting into multiple actions adds complexity, not resilience. Storing artifacts in different bucket is not relevant.

Answer

Store build artifacts in a different S3 bucket.

Answer

Add a manual approval stage before the build stage.

Answer

Configure the build stage to run multiple build actions in parallel.

Answer

Use a different source repository, such as CodeCommit.

Question 13

A developer is building a serverless application using AWS Lambda and Amazon API Gateway. The application must authenticate users using a third-party OAuth 2.0 provider. Which THREE options can the developer use to integrate with the OAuth provider?

Accepted Answer

Use a Lambda authorizer in API Gateway to validate the OAuth token.. API Gateway Lambda authorizer can call the OAuth provider to validate tokens. Cognito User Pools can be configured as an OAuth 2.0 provider and integrated with API Gateway. Custom Lambda function can validate tokens directly. API Gateway resource policy is for IP whitelisting, not authentication. IAM authorization is for AWS credentials.

Answer

Use an API Gateway resource policy to allow only authenticated users.

Answer

Use IAM authorization with a custom token service.

Question 14

A company is using AWS Elastic Beanstalk to deploy a web application. The environment is running behind a load balancer. The developer needs to ensure that the application logs are centralized and retained for analysis. Which TWO services can be used to collect and store logs from the EC2 instances?

Accepted Answer

Amazon CloudWatch Logs. CloudWatch Logs agent sends logs to CloudWatch Logs for centralized storage. S3 can be used as a destination for log exports. X-Ray is for tracing, not log collection. Kinesis Data Firehose can stream logs to destinations but is not directly installed on instances. CloudTrail records API calls, not application logs.

Answer

AWS X-Ray

Answer

Amazon Kinesis Data Firehose

Answer

AWS CloudTrail

Question 15

A developer needs to store a large number of binary files (e.g., images) that are accessed infrequently but must be retrievable within minutes. The storage solution should be cost-effective. Which Amazon S3 storage class is MOST suitable?

Accepted Answer

S3 Glacier Instant Retrieval. Option C is correct because S3 Glacier Instant Retrieval is for long-lived, rarely accessed data that requires millisecond retrieval, but with a retrieval cost. Option A is wrong because S3 Standard is for frequently accessed data. Option B is wrong because S3 Intelligent-Tiering is for unknown or changing access patterns. Option D is wrong because S3 One Zone-IA is for infrequent access but less durable.

Answer

S3 Intelligent-Tiering

Answer

S3 One Zone-Infrequent Access

Answer

S3 Standard