DVA-C02 Exam Simulation — 65 Questions

Question 1

A developer is creating an API with Amazon API Gateway that needs to accept binary data (e.g., images) and store them directly in an S3 bucket. The developer wants to minimize backend complexity. Which integration type should be used?

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

Accepted Answer

AWS service integration with S3. AWS service integration with S3 allows API Gateway to directly proxy binary data (e.g., images) to an S3 bucket without invoking a Lambda function or other backend. This minimizes backend complexity because the API Gateway handles the request transformation and passes the payload directly to S3 via the PutObject API action, eliminating the need for custom code.

Answer

Lambda proxy integration

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HTTP integration

Answer

Mock integration

Question 2

A developer is using AWS CodePipeline to deploy a web application. The pipeline has stages: Source, Build, Staging Deploy, Staging Test, and Prod Deploy. The developer wants to ensure that if the Staging Test stage fails, the pipeline automatically stops and does not proceed to Prod Deploy. Which action should the developer take?

Accepted Answer

No action is needed; CodePipeline automatically stops on stage failure. AWS CodePipeline's default behavior is to stop execution when a stage fails, preventing the pipeline from proceeding to subsequent stages. When the Staging Test stage fails, the pipeline transitions to a 'Failed' status and does not automatically continue to Prod Deploy. No additional configuration is required for this behavior.

Answer

Add a manual approval step before Prod Deploy

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Disable the transition from Staging Test to Prod Deploy

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Configure the pipeline execution mode to 'Superseded'

Question 3

A developer needs to grant an IAM role in the same AWS account read-only access to objects in a specific S3 bucket. The bucket is configured with a bucket policy that has an explicit Deny statement denying all principals except the root user. Which approach should the developer use to grant the required access?

Accepted Answer

Modify the bucket policy to allow the IAM role explicitly, or remove the Deny statement. The bucket policy contains an explicit Deny that overrides any allow permissions, including those granted by an IAM policy attached to the role. To grant the IAM role read-only access, the developer must either remove the Deny statement or add an explicit Allow for the role in the bucket policy, because an explicit Deny in a resource-based policy cannot be overridden by an identity-based policy.

Answer

Attach an IAM policy to the role that allows s3:GetObject on the bucket

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Use an S3 access point instead of the bucket directly

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Make the bucket public to allow all access

Question 4

A team uses AWS CodeCommit for source control and wants to automatically trigger a build and deployment when code is pushed to the master branch. Which AWS service should be used to create this automation?

Accepted Answer

AWS CodePipeline. AWS CodePipeline is the correct service because it is a fully managed continuous delivery service that can be configured to automatically start a pipeline execution when a change is pushed to a specific branch in AWS CodeCommit. By setting the source stage to the CodeCommit repository and master branch, CodePipeline triggers subsequent build and deploy actions without manual intervention, enabling a complete CI/CD workflow.

Answer

AWS CodeBuild

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AWS Lambda

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AWS CodeDeploy

Question 5

A company wants to encrypt data at rest in Amazon RDS for MySQL. Which TWO actions should be taken?

Accepted Answer

Enable encryption at rest when creating the DB instance.. Amazon RDS for MySQL supports encryption at rest only at the time of DB instance creation. You must enable the encryption option in the console or specify the --storage-encrypted flag in the AWS CLI when launching the instance. Once enabled, RDS automatically encrypts the underlying storage, automated backups, read replicas, and snapshots using AES-256 encryption, with keys managed through AWS KMS.

Answer

Encrypt individual tables using MySQL native encryption.

Answer

Enable encryption at rest after the DB instance is created.

Answer

Use client-side encryption to encrypt data before sending to RDS.

Question 6

A company uses AWS KMS to encrypt data in S3. The security team wants to ensure that all KMS keys are rotated every year. Which action should be taken?

Accepted Answer

Enable automatic key rotation. AWS KMS supports automatic key rotation for customer-managed KMS keys. When enabled, KMS rotates the key material annually without requiring any manual intervention or application changes. This satisfies the security team's requirement for yearly rotation while maintaining the same key ID and existing encrypted data accessibility.

Answer

Manually rotate the KMS key every year

Answer

Create a new KMS key and update all applications to use it

Answer

Use AWS CloudWatch Events to trigger a Lambda function that rotates the key

Question 7

A developer uses AWS CodeCommit to store source code. The developer wants to automatically trigger a build in AWS CodeBuild every time a new commit is pushed to the master branch. Which AWS service should the developer use to configure this integration?

Accepted Answer

AWS CodePipeline. AWS CodePipeline is the correct service because it provides a fully managed continuous delivery service that can be configured to automatically start a pipeline execution whenever a new commit is pushed to a specific branch in AWS CodeCommit. By setting up a CodeCommit source action in a pipeline, CodePipeline uses webhooks or polling to detect changes and then triggers the build project in AWS CodeBuild as the next stage. This creates a seamless CI/CD workflow without requiring custom event rules or additional services.

Answer

Amazon CloudWatch Events (or EventBridge)

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Amazon S3 events

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AWS CodeDeploy

Question 8

A developer is building a serverless application using AWS Step Functions. The workflow must execute hundreds of thousands of short-lived tasks per day, each taking less than 30 seconds. The tasks need to run in parallel, and a small number of duplicate executions are acceptable. Which type of Step Functions workflow should the developer choose?

Accepted Answer

Express Workflow. Express Workflows are designed for high-volume, short-duration (under 5 minutes) event-processing workloads, executing hundreds of thousands of state transitions per second with at-least-once semantics. Since the tasks are short-lived (under 30 seconds), run in parallel, and tolerate a small number of duplicate executions, Express Workflow is the correct choice because it offers lower cost and higher throughput than Standard Workflow, which guarantees exactly-once execution and is better suited for long-running, auditable workflows.

Answer

Standard Workflow

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AWS Lambda function with synchronous invocation

Answer

Amazon Simple Workflow Service (SWF)

Question 9

A developer is writing a Lambda function that processes images uploaded to an S3 bucket. The function needs to extract metadata from the image. Which S3 feature can be used to automatically trigger the Lambda function?

Accepted Answer

S3 Events. Amazon S3 Events can be configured to send a notification when an object is created (e.g., via PutObject) in an S3 bucket. This event can directly invoke an AWS Lambda function, making it the correct service to automatically trigger the function upon image upload. The developer simply needs to set up an S3 event notification with the Lambda function as the destination.

Answer

S3 Inventory

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S3 Transfer Acceleration

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S3 Batch Operations

Question 10

A company is deploying a critical application using AWS CloudFormation. The stack creation fails due to a resource creation failure. The developer needs to troubleshoot the issue. Which TWO actions should the developer take to identify the root cause? (Choose TWO.)

Accepted Answer

View the stack events in the CloudFormation console.. Options A and D are correct. A: Viewing stack events (Events tab) shows error messages for each resource, which can indicate which resource failed and why. D: Reviewing the stack template for logical errors can help identify issues like missing dependencies or incorrect parameter values. Option B is wrong because stack outputs are only available after successful creation; during a failure, outputs are not generated. Option C is wrong because deleting and recreating the stack with the same parameters will likely result in the same failure and also removes the stack's logs and events, losing troubleshooting information. Option E is wrong because CloudTrail logs API calls made to AWS, but CloudFormation-specific errors during resource creation are not detailed in CloudTrail; stack events provide more relevant information.

Answer

Check the stack outputs.

Answer

Delete the stack and recreate it with the same parameters.

Answer

Check AWS CloudTrail logs for the stack creation attempt.

Question 11

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

Answer

Use Amazon ElastiCache and modify the Lambda function to check cache

Question 12

A company is deploying a new web application on Amazon EC2 instances behind an Application Load Balancer. The application must be deployed with no downtime. The deployment uses AWS CodeDeploy with a Blue/Green deployment configuration. Which TWO actions should be taken to achieve zero-downtime deployment? (Choose TWO.)

Accepted Answer

Create a new Auto Scaling group with the new application version and register it with the ALB.. In a Blue/Green deployment, you create a new Auto Scaling group with the new application version and register it with the existing ALB. Option E is correct because after the new environment is ready, you gradually shift traffic from the old environment to the new environment using the ALB to ensure zero downtime. Option A is incorrect because you should reuse the existing ALB to avoid re-creating DNS and other configurations. Option C is incorrect because updating the existing Auto Scaling group in-place would cause downtime (rolling update) rather than a true Blue/Green deployment. Option D is incorrect because terminating old instances immediately could cause downtime if the new environment fails; you should allow rollback by keeping old instances until traffic is fully shifted.

Answer

Create a new load balancer for the new environment.

Answer

Update the existing Auto Scaling group with the new application version.

Answer

Terminate the old EC2 instances immediately after deploying the new ones.

Question 13

A developer is troubleshooting a slow RDS MySQL instance. Which TWO metrics in Amazon CloudWatch should the developer examine first?

Accepted Answer

CPUUtilization. The correct metrics to examine first for a slow RDS MySQL instance are CPUUtilization and ReadLatency. High CPUUtilization indicates that the instance is under heavy load, possibly from inefficient queries or inadequate compute capacity. High ReadLatency suggests slow I/O, which could be due to disk contention or suboptimal queries. NetworkReceiveThroughput (A) is related to network traffic, not database performance. SwapUsage (B) is not typically a primary metric for RDS performance. FreeStorageSpace (D) indicates storage capacity but does not directly measure performance. Therefore, options C and E are the correct choices.

Answer

NetworkReceiveThroughput

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SwapUsage

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FreeStorageSpace

Question 14

A developer is deploying a serverless application using AWS CloudFormation. The stack creation fails with the error 'CREATE_FAILED: The following resource(s) failed to create: [MyLambdaFunction]'. The developer checks the CloudFormation events and sees 'Resource creation cancelled'. What is the most likely cause?

Accepted Answer

Another resource in the stack failed, triggering a rollback and cancelling the Lambda creation.. The error 'Resource creation cancelled' indicates that the creation of the Lambda function was aborted because another resource in the stack failed. CloudFormation by default rolls back the stack on failure, cancelling any in-progress resource creations. Thus, option C is correct. Option A is incorrect because large code would cause a different error (e.g., 'RequestEntityTooLargeException'). Option B is incorrect because a timeout would show 'CREATE_FAILED' with a timeout message, not 'cancelled'. Option D is incorrect because missing permissions would result in a different error (e.g., 'AccessDeniedException') during invocation, not creation.

Answer

The Lambda function code is too large and exceeds the deployment limit.

Answer

The Lambda function creation timed out due to a network issue.

Answer

The Lambda function's execution role is missing permissions.

Question 15

A developer is optimizing an S3 bucket for static website hosting. The site has a main page (index.html) and an error page (error.html). Users report seeing a generic 403 error instead of the error page when accessing a missing object. What is the likely cause?

Accepted Answer

The Error document field in the static website hosting configuration is not set to error.html.. When static website hosting is enabled on an S3 bucket, the Error Document field specifies the object served when a 403 or 404 error occurs. If this field is not set to error.html, S3 returns its generic 403 error response instead of the custom error page. The correct answer is B because the Error document configuration is missing or incorrect.

Answer

The bucket policy denies access to the error.html object.

Answer

The index.html is missing from the bucket.

Answer

The error.html object has incorrect permissions.

Question 16

A developer is building a microservices application that processes event messages from multiple sources. The application requires at-least-once delivery, but message ordering is not important. Which Amazon SQS queue type should the developer use?

Accepted Answer

Standard queue. Amazon SQS Standard queues provide at-least-once delivery and best-effort ordering, making them ideal for microservices that can tolerate duplicate messages and do not require strict message sequencing. Since the application processes events from multiple sources and message ordering is not important, a Standard queue meets the requirements without the throughput limitations of FIFO queues.

Answer

FIFO queue

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Dead-letter queue

Answer

Delay queue

Question 17

A developer is building a serverless application using AWS Lambda to process images uploaded to an S3 bucket. The Lambda function needs to resize the image and store the result in another S3 bucket. The developer notices that the Lambda function fails intermittently with timeout errors for large images. What is the MOST efficient solution to resolve this issue?

Accepted Answer

Increase the Lambda function timeout and memory allocation to accommodate larger images.. Increasing the Lambda function timeout and memory allocation directly addresses the root cause of the failure: large images require more processing time and memory. Lambda's CPU and I/O throughput scale proportionally with allocated memory, so raising both parameters provides the necessary resources to complete the resize operation within the function's execution environment.

Answer

Limit the S3 event notification to only trigger for images smaller than 5 MB.

Answer

Refactor the Lambda function to use multi-threading for parallel processing of image chunks.

Answer

Use AWS Step Functions to orchestrate the image processing in smaller steps.

Question 18

A developer is building a serverless API using Amazon API Gateway and AWS Lambda. The API accepts JSON payloads in the request body. The developer wants to ensure that incoming requests have a valid structure before being passed to the Lambda function to reduce unnecessary invocations. Which API Gateway feature should the developer use?

Accepted Answer

Request validation using models and request validators. API Gateway's request validation feature allows you to define a JSON Schema model for the request body and attach a request validator to the method. This validates the payload structure before the request reaches the Lambda function, preventing invalid payloads from triggering unnecessary invocations and reducing costs.

Answer

Usage plans with API keys

Answer

WAF (AWS WAF) integration

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Custom authorizer (Lambda authorizer)

Question 19

A developer wants to store application configuration securely and retrieve it programmatically from EC2 instances. The configuration includes database passwords and API keys. Which AWS service should be used?

Accepted Answer

AWS Systems Manager Parameter Store with SecureString. AWS Systems Manager Parameter Store with SecureString is the correct choice because it is purpose-built for securely storing sensitive configuration data like database passwords and API keys. It integrates with AWS KMS for encryption at rest, supports versioning, and allows EC2 instances to retrieve values via the AWS CLI or SDK using IAM roles, eliminating the need to hardcode secrets.

Answer

EC2 user data

Answer

Amazon S3 with server-side encryption

Answer

AWS CloudFormation template parameters

Question 20

A company runs an application on Amazon EC2 instances that need to read data from an Amazon DynamoDB table. The developer must grant access to DynamoDB without storing any long-term credentials on the instance. Which approach should the developer use?

Accepted Answer

Use an IAM role and attach it to the EC2 instance profile.. Attaching an IAM role to an EC2 instance profile allows the instance to obtain temporary security credentials from the AWS Security Token Service (STS) via the instance metadata service. This eliminates the need to store long-term credentials on the instance, adhering to the principle of least privilege and improving security posture.

Answer

Store the AWS access key and secret key in a configuration file.

Answer

Use an IAM user and store credentials in AWS Secrets Manager.

Answer

Use the DynamoDB table's resource-based policy to allow the EC2 instance.