DOP-C02 Practice Test 31 — 15 Questions

Question 1

A company is using AWS CloudFormation to deploy infrastructure. They want to receive notifications when a stack operation fails, including the specific resource that caused the failure. Which approach should they use?

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

Accepted Answer

Configure an SNS topic as a notification option in the CloudFormation stack and subscribe to receive stack events.. CloudFormation allows you to specify an SNS topic ARN as a notification option when creating or updating a stack. When a stack operation fails, CloudFormation publishes a notification to that SNS topic, and the notification includes the logical resource ID and the status reason for the failure. This provides real-time, event-driven notifications without requiring polling or additional services.

Answer

Create a CloudWatch alarm on the 'StackFailure' metric.

Answer

Create an AWS Lambda function that polls the CloudFormation DescribeStackEvents API every minute and sends an email on failure.

Answer

Enable AWS CloudTrail to log CloudFormation API calls and configure an SNS notification on the trail.

Question 2

A company has a production environment that uses Amazon Route 53 for DNS and an Application Load Balancer (ALB) to distribute traffic to EC2 instances. The company wants to implement a disaster recovery plan that automatically fails over to a secondary region in case the primary region becomes unavailable. Which configuration should be used?

Accepted Answer

Use Route 53 failover routing policy with primary and secondary records and health checks.. Route 53 failover routing is purpose-built for active-passive DR: you designate a PRIMARY record and a SECONDARY record, attach a health check to the primary, and Route 53 automatically returns the secondary record's value when the primary health check fails. This gives deterministic, automatic regional failover without manual DNS changes. The other policies distribute traffic but do not implement a primary/secondary failover decision.

Answer

Use Route 53 weighted routing policy with equal weights for both regions.

Answer

Use Route 53 geolocation routing policy to route users based on their location.

Answer

Use Route 53 latency routing policy to route to the region with lowest latency.

Question 3

Which THREE practices help ensure the security of a CI/CD pipeline that deploys to production? (Choose three.)

Accepted Answer

Integrate static code analysis and vulnerability scanning into the pipeline.. Static code analysis and vulnerability scanning (option A) are essential for identifying security flaws early in the development lifecycle, preventing vulnerable code from reaching production. Integrating these tools into the CI/CD pipeline ensures that every commit is automatically checked against known vulnerabilities and coding standards, reducing the risk of deploying exploitable code.

Answer

Require manual approval for all deployments to production.

Answer

Store deployment credentials in the source repository for traceability.

Question 4

A DevOps engineer is designing a CI/CD pipeline for a microservices architecture on AWS. They want to use AWS CodeDeploy to deploy applications to an Auto Scaling group. The pipeline must ensure that only a small percentage of instances are updated at a time, and if health checks fail, the deployment is automatically rolled back. Which deployment configuration should be used?

Accepted Answer

In-place deployment with 'CodeDeployDefault.OneAtATime' configuration and automatic rollback enabled.. `CodeDeployDefault.OneAtATime` deploys to one instance at a time, which is the smallest possible batch and satisfies the 'small percentage of instances' requirement. Enabling automatic rollback ensures that if health checks fail, CodeDeploy reverts to the last known good revision, meeting the rollback requirement.

Answer

Blue/green deployment with a fixed number of instances.

Answer

In-place deployment with 'CodeDeployDefault.AllAtOnce' configuration.

Answer

In-place deployment with 'CodeDeployDefault.HalfAtATime' configuration.

Question 5

A DevOps engineer is setting up monitoring for an Amazon S3 bucket that stores sensitive data. The engineer needs to be notified whenever an object in the bucket is accessed by a user or application, including read and write operations. Which AWS service should the engineer use to capture these events and trigger notifications?

Accepted Answer

Configure S3 event notifications to send events to an SNS topic for object-level operations.. Amazon S3 can be configured to send event notifications to SNS, SQS, or Lambda for object-level operations (e.g., PutObject, GetObject). This provides real-time notifications for read and write access. Option B is incorrect because CloudTrail data events capture object-level API calls but do not provide real-time notifications; they require additional setup with CloudWatch Logs and alarms. Option C is incorrect because AWS Config records configuration changes, not individual object access events. Option D is incorrect because CloudWatch metrics track bucket-level statistics, not per-object access, and cannot trigger notifications for individual object access.

Answer

Enable AWS CloudTrail data events for the S3 bucket and configure CloudWatch alarms on the log group.

Answer

Use AWS Config to record S3 resource changes and trigger an SNS notification.

Answer

Use Amazon CloudWatch metrics for the S3 bucket and set an alarm on the NumberOfObjects metric.

Question 6

A company uses AWS Lambda to process messages from an Amazon SQS queue. The Lambda function occasionally times out after 15 seconds. To improve resilience, the team wants to ensure messages are not lost and are retried. Which configuration is MOST appropriate?

Accepted Answer

Increase the Lambda timeout to 30 seconds and configure a dead-letter queue (DLQ) for the SQS queue.. Increasing the Lambda timeout to 30 seconds accommodates the occasional processing delays that cause the current 15-second timeout, preventing premature failures. Configuring a dead-letter queue (DLQ) for the SQS queue ensures that messages that repeatedly fail after all retries are exhausted are preserved for analysis and manual reprocessing, rather than being lost. This combination directly addresses the requirement to not lose messages and to allow retries, as Lambda will automatically retry failed invocations up to the function's configured retry count (default 2) before sending the message to the DLQ.

Answer

Reduce the Lambda timeout to 5 seconds to fail fast and retry quickly.

Answer

Set the SQS queue visibility timeout to less than the Lambda timeout.

Answer

Increase the batch size and remove the DLQ to speed up processing.

Question 7

A company wants to automatically recover an Amazon RDS DB instance if the underlying hardware fails. Which feature should the DevOps engineer enable?

Accepted Answer

Multi-AZ deployment.. Multi-AZ deployment maintains a synchronous standby replica in a different Availability Zone and automatically fails over to it if the primary instance's hardware fails, the AZ becomes unavailable, or the instance is rebooted with failover. This is the only RDS feature designed for automatic hardware-failure recovery with minimal downtime (typically 60–120 seconds). Deletion protection, cross-Region read replicas, and automated backups do not provide automatic failover on hardware failure.

Answer

Deletion protection.

Answer

Read replicas in a different Region.

Answer

Automated backups with a retention period of 35 days.

Question 8

A DevOps engineer is troubleshooting a Lambda function that times out after 3 seconds. The function makes an HTTP request to an external API. The function's timeout setting is 10 seconds. What is the most likely cause of the timeout?

Accepted Answer

The HTTP client's timeout is set to a low value.. The Lambda function times out after 3 seconds, which is most likely due to an HTTP client timeout explicitly set to a low value (e.g., 3 seconds) inside the function code. Even though the Lambda function's configured timeout is 10 seconds, the HTTP client's internal timeout fires first, causing the function to fail before the Lambda timeout is reached. This is the most likely cause because the symptom matches a client-side timeout rather than a server-side or infrastructure issue.

Answer

The external API is throttling the request.

Answer

The Lambda function is not in a VPC.

Answer

The Lambda function's memory is insufficient.

Question 9

A DevOps engineer wants to use AWS CodeDeploy to deploy an application to an Auto Scaling group. The deployment must ensure that only a certain percentage of instances are taken out of service at a time. Which deployment configuration supports this requirement?

Accepted Answer

CodeDeployDefault.OneAtATime. CodeDeployDefault.OneAtATime is the correct deployment configuration because it ensures that only one instance in the Auto Scaling group is taken out of service at a time, which directly satisfies the requirement of limiting the percentage of instances removed during deployment. This configuration is designed for EC2/On-Premises deployments and uses a fixed number of instances (one) rather than a percentage, making it ideal for gradual, safe rollouts.

Answer

CodeDeployDefault.LambdaCanary10Percent5Minutes

Answer

CodeDeployDefault.AllAtOnce

Answer

CodeDeployDefault.LambdaLinear10PercentEvery1Minute

Question 10

A company runs a critical e-commerce application on AWS. They use AWS CodePipeline to manage deployments. The pipeline has a source stage (CodeCommit), a build stage (CodeBuild), and a deploy stage (CodeDeploy to an Auto Scaling group). Recently, a deployment caused a 5-minute outage because the new application version had a bug that caused the health checks to fail. The Auto Scaling group marked instances as unhealthy and replaced them, but during the replacement, traffic was routed to the remaining instances, which also failed health checks, causing a full outage. The company wants to implement a deployment strategy that prevents any traffic from being routed to unhealthy instances and automatically rolls back if the deployment fails. They also want to minimize deployment time and cost. Which solution should the DevOps team implement?

Accepted Answer

Use CodeDeploy blue/green deployment with automatic rollback enabled. The correct solution is to use a blue/green deployment with CodeDeploy and automatic rollback enabled. In a blue/green deployment, a new Auto Scaling group (green) is created alongside the existing one (blue). Traffic is shifted to the green group only after all health checks pass. If health checks fail, the deployment is automatically rolled back by terminating the green group, ensuring no traffic is routed to unhealthy instances. This prevents any outage. Option B (in-place deployment with rollback) updates instances in place, which can cause downtime if instances fail health checks, as the Auto Scaling group replaces them sequentially, potentially routing traffic to unhealthy instances. Option A (manual approval) slows down deployment and does not automate rollback based on health checks. Option D (increasing health check grace period) only delays detection of failures and does not prevent traffic from being routed to unhealthy instances.

Answer

Add a manual approval step in CodePipeline before deploy

Answer

Use CodeDeploy in-place deployment with automatic rollback enabled

Answer

Increase the health check grace period in the Auto Scaling group

Question 11

A team uses AWS CodePipeline to orchestrate deployments. They want to integrate a manual approval step before deploying to production. Which action should they take?

Accepted Answer

Add a manual approval action to the pipeline before the production deployment stage.. AWS CodePipeline natively supports a manual approval action that can be added as a stage before the production deployment. This action pauses the pipeline and sends a notification (via Amazon SNS) to specified approvers, who can then approve or reject the deployment through the AWS Management Console, CLI, or API. No custom code or external services are required.

Answer

Use an AWS Lambda function to send an approval request email and wait for HTTP response.

Answer

Add an Amazon CloudWatch Events rule to pause the pipeline before the production stage.

Answer

Add an Amazon SNS topic to the pipeline and require subscription confirmation.

Question 12

A company uses AWS CodePipeline to automate deployments. The pipeline consists of Source, Build, and Deploy stages. The Build stage uses CodeBuild, and the Deploy stage uses CodeDeploy. Recently, the pipeline failed at the Deploy stage with an error: 'The deployment group does not exist'. Which TWO actions should the team take to resolve this issue?

Accepted Answer

Verify that the deployment group name specified in the pipeline's Deploy stage matches the actual deployment group name in CodeDeploy.. The error 'The deployment group does not exist' directly indicates a mismatch between the deployment group name specified in the CodePipeline Deploy stage configuration and the actual deployment group name defined in CodeDeploy. The pipeline's Deploy stage action references a deployment group by name; if that name does not match an existing group in CodeDeploy, the deployment fails. Verifying and correcting this name resolves the issue.

Answer

Increase the timeout for the Deploy stage to allow more time for the deployment group to be created.

Answer

Ensure that the CodeBuild project has permissions to access the CodeDeploy deployment group.

Answer

Check that the CodeDeploy application exists in the same AWS account as the pipeline.

Question 13

A company is experiencing a DDoS attack on its application hosted on AWS. The application uses an Application Load Balancer (ALB) with an Auto Scaling group of EC2 instances. The security team needs to mitigate the attack with minimal latency impact on legitimate users. Which THREE actions should the team take? (Choose THREE.)

Accepted Answer

Enable AWS Shield Advanced on the ALB.. AWS Shield Advanced provides enhanced DDoS mitigation for ALBs, including access to the DDoS Response Team (DRT) and financial protection against scaling costs. It operates at the network and transport layers with minimal latency, as it inspects traffic inline without introducing significant processing delay. This makes it a critical first line of defense for high-availability applications under attack.

Answer

Disable cross-zone load balancing on the ALB to limit the number of instances receiving traffic.

Answer

Configure the Auto Scaling group to scale based on the NetworkIn metric to handle the increased traffic.

Question 14

A DevOps team uses AWS CloudFormation with nested stacks. They are experiencing stack update failures because changes to a nested stack cause resource conflicts. Which THREE best practices should they follow to manage nested stack updates? (Choose THREE.)

Accepted Answer

Apply a stack policy to prevent updates to critical resources in the nested stacks.. Applying a stack policy to nested stacks prevents updates to critical resources, avoiding conflicts during nested stack updates. Stack policies act as a guard to deny updates to specified resources, which is essential when changes to a nested stack might cause resource conflicts or unintended modifications. This best practice ensures that only intended changes are applied, reducing the risk of update failures.

Answer

Set the stack update to disable rollback to allow debugging of failures.

Answer

Use DependsOn to ensure nested stacks are updated in a specific order.

Question 15

A CloudFormation template includes the following resource:

MySecurityGroup:
    Type: AWS::EC2::SecurityGroup
    Properties:
      GroupDescription: My security group
      SecurityGroupIngress:
        - IpProtocol: tcp
          FromPort: 443
          ToPort: 443
          CidrIp: 0.0.0.0/0

MyInstance:
    Type: AWS::EC2::Instance
    Properties:
      ImageId: ami-0abcdef1234567890
      InstanceType: t2.micro
      SecurityGroupIds: !Ref MySecurityGroup

The stack creation fails with the error shown. What is the cause?

Accepted Answer

The SecurityGroupIds property must be a list, but !Ref returns a single value.. The error occurs because the `SecurityGroupIds` property expects a list of security group IDs, but the `!Ref` intrinsic function returns a single security group ID (a string), not a list. In CloudFormation, `!Ref` for a security group returns its ID as a scalar value, so wrapping it in a list (e.g., `[!Ref MySecurityGroup]`) is required to satisfy the `List<String>` type constraint.

Answer

The SecurityGroupIds property must be a list of security group names, not IDs.

Answer

The security group ingress rule is invalid because it allows all traffic.

Answer

The ImageId is missing, so the security group validation fails first.