DVA-C02 Practice Test 9 — 10 Questions

Question 1

A company is deploying a web application on EC2 instances behind an Application Load Balancer. The application needs to authenticate users using a third-party identity provider that supports SAML 2.0. The company wants to use AWS Identity and Access Management (IAM) to manage user permissions. Which solution should the developer implement?

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

Accepted Answer

Create an IAM identity provider for the SAML IdP and set up a role with a trust policy that allows federated users to assume it.. It describes the standard AWS pattern for SAML 2.0 federation: creating an IAM identity provider for the external SAML IdP, then configuring an IAM role with a trust policy that allows users authenticated by that IdP to assume the role. This enables the application to use IAM to manage permissions for federated users without creating IAM users in the AWS account.

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Use AWS Security Token Service (STS) to generate temporary credentials for the users.

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Store the SAML metadata document in AWS Certificate Manager.

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Use Amazon Cognito user pools with a SAML identity provider.

Question 2

A developer wants to invoke an AWS Lambda function every hour to perform a maintenance task. Which AWS service should be used to schedule the invocation?

Accepted Answer

Amazon CloudWatch Events (EventBridge). Amazon CloudWatch Events (now part of Amazon EventBridge) is the correct service for scheduling periodic invocations of AWS Lambda functions. It allows you to create a rule with a cron or rate expression (e.g., `rate(1 hour)`) that triggers the Lambda function on a defined schedule. This is the native, serverless way to run code on a recurring timer without managing any infrastructure.

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Amazon Simple Queue Service (SQS)

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AWS Step Functions

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Amazon Simple Notification Service (SNS)

Question 3

A developer is using AWS CodePipeline with multiple actions in a stage. The pipeline has a build action that produces artifacts, followed by a deploy action. The developer wants to ensure that if the deploy action fails, the pipeline stops and does not continue to the next stage. How can they achieve this?

Accepted Answer

No additional configuration is needed; the pipeline stops on failure by default.. AWS CodePipeline stages are sequential by default: if any action within a stage fails, the entire stage fails and the pipeline stops, preventing execution of subsequent stages. No additional configuration is needed to halt the pipeline on a deploy action failure, as this is the inherent behavior of a pipeline stage with multiple actions.

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Configure the deploy action to 'Abort' on failure.

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Set the runOrder for the deploy action to 'Blocked'.

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Set the pipeline's execution mode to 'PARALLEL'.

Question 4

A developer is building a chat application using WebSockets. The application runs on multiple EC2 instances and needs to broadcast messages to all connected clients. Which AWS service can handle the WebSocket connections and route messages?

Accepted Answer

Amazon API Gateway WebSocket API. Amazon API Gateway WebSocket API is the correct choice because it natively manages WebSocket connections, maintains persistent bidirectional communication, and can broadcast messages to all connected clients using callback URLs. It handles connection lifecycle (connect, disconnect, default) and integrates with AWS Lambda or other backends to route messages efficiently.

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Amazon SQS with long polling

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Application Load Balancer with WebSocket support

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Amazon CloudFront with WebSocket support

Question 5

A developer is deploying an application that uses Amazon SQS queues. The messages contain sensitive data that must be encrypted at rest. Which TWO actions should the developer take? (Choose TWO.)

Accepted Answer

Configure the SQS queue to use a customer managed KMS key.. Configuring an SQS queue to use a customer managed KMS key gives you control over the key lifecycle, including rotation and access policies, while still leveraging AWS KMS for server-side encryption. Option D is also correct because enabling server-side encryption (SSE) for SQS using AWS KMS encrypts messages at rest automatically, without requiring client-side changes. Together, these two actions ensure that sensitive data in SQS messages is encrypted at rest using KMS, meeting the requirement.

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Encrypt the messages client-side before sending to SQS.

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Store the messages in an S3 bucket with default encryption instead of using SQS.

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Use AWS CloudHSM to generate and store the encryption keys.

Question 6

A developer is using AWS CodeDeploy to deploy an application to an EC2 instance. The deployment fails with the error 'ScriptMissing' during the BeforeInstall lifecycle event. What is the most likely cause?

Accepted Answer

The script file specified in the appspec.yml for the BeforeInstall hook is not present on the instance. The 'ScriptMissing' error in AWS CodeDeploy indicates that the deployment failed because a script file referenced in the appspec.yml for a lifecycle event (in this case, BeforeInstall) could not be found on the EC2 instance. CodeDeploy expects the script to be present at the specified path after the archive is extracted; if the file is missing or the path is incorrect, the agent reports this error. Option B correctly identifies that the script file is not present on the instance.

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The BeforeInstall lifecycle event is not defined in the appspec.yml

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The CodeDeploy agent on the instance is not running

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The instance does not have the necessary permissions to execute the script

Question 7

A company runs a containerized application on Amazon ECS with Fargate launch type. The application needs to access an Amazon RDS MySQL database using credentials stored in AWS Secrets Manager. The ECS task role has the following IAM policy: {"Version":"2012-10-17","Statement":[{"Effect":"Allow","Action":["secretsmanager:GetSecretValue"],"Resource":"arn:aws:secretsmanager:us-east-1:123456789012:secret:prod-db-*"}]}. The application fails to retrieve the secret with an AccessDeniedException. What is the most likely cause?

Accepted Answer

The secret's resource-based policy denies access to the task role.. The IAM policy on the ECS task role allows access to secrets matching the pattern `prod-db-*`. However, if the secret has a resource-based policy that explicitly denies access to the task role, that denial overrides the IAM allow, causing an AccessDeniedException. AWS Secrets Manager evaluates both identity-based policies (task role) and resource-based policies, and an explicit deny in either results in denial.

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The task execution role does not have permission to retrieve the secret.

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The task is in a private subnet without a VPC endpoint to Secrets Manager.

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The secret name does not match the pattern in the policy.

Question 8

A developer is deploying a web application using AWS Elastic Beanstalk. The application needs to store session state. The developer wants to ensure that session data is not lost if an EC2 instance is terminated. Which solution should the developer implement?

Accepted Answer

Store session data in an Amazon ElastiCache cluster.. Amazon ElastiCache provides a managed, highly available, and durable in-memory cache that can store session state externally from EC2 instances. By using ElastiCache (e.g., Redis with replication and persistence), session data survives instance termination because it is stored in a separate, resilient service, not on the local instance.

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Store session data in an Amazon EBS volume.

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Store session data in an Amazon S3 bucket.

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Store session data in the instance store.

Question 9

A Lambda function needs temporary scratch space larger than the default while processing images. Which setting should be adjusted?

Accepted Answer

Ephemeral storage size for /tmp. Lambda functions have a default /tmp storage of 512 MB, which is insufficient for large image processing tasks. Adjusting the ephemeral storage size (up to 10,240 MB) provides the necessary scratch space for temporary files, such as intermediate image buffers or resized outputs, without requiring external storage like EFS.

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Reserved concurrency

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Function URL auth type

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Dead-letter queue target

Question 10

An API Gateway REST API invokes Lambda synchronously. Clients receive 502 responses after a deployment, but Lambda logs show a successful business operation. What is the most likely issue?

Accepted Answer

The Lambda proxy integration response format is invalid. Lambda proxy integration requires the response to be in a specific JSON format: `{"statusCode": ..., "headers": ..., "body": ...}`. If the Lambda function returns a plain string or an object missing these keys, API Gateway cannot map it to an HTTP response, resulting in a 502 Internal Server Error. The successful business operation in logs confirms the Lambda code ran correctly, but the malformed response format causes the gateway error.

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The Lambda execution role lacks dynamodb:PutItem

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The API cache TTL is too short

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The API stage has X-Ray tracing enabled