DOP-C02 Amazon Web Services AWS Certified DevOps Engineer - Professional Free Practice Exam Questions (2026 Updated)

The best solution to implement failover for the application is to use CloudFront origin groups. Origin groups allow CloudFront to automatically switch to a secondary origin when the primary origin is unavailable or returns specific HTTP status codes that indicate a failure1. This way, CloudFront can serve the requests from the secondary ALB in the secondary Region without any delay or redirection. To set up origin groups, the DevOps engineer needs to create a new origin on the distribution for the secondary ALB, create a new origin group with the original ALB as the primary origin and the secondary ALB as the secondary origin, and configure the origin group to fail over for HTTP 5xx status codes. Then, the DevOps engineer needs to update the default behavior to use the origin group instead of the single origin2.

The other options are not as effective or efficient as the solution in option B. Option A is not suitable because creating a second CloudFront distribution will increase the complexity and cost of the application. Moreover, using Route 53 alias records with a failover policy will introduce some delay in detecting and switching to the secondary CloudFront distribution, which may not meet the zero-second RTO requirement. Option C is not feasible because CloudFront does not support using Route 53 alias records as origins3. Option D is not advisable because using a CloudFront function to redirect the requests to the secondary ALB will add an extra round-trip and latency to the failover process, which may also not meet the zero-second RTO requirement.

1: Optimizing high availability with CloudFront origin failover - Amazon CloudFront

2: Creating an origin group - Amazon CloudFront

3: Values That You Specify When You Create or Update a Web Distribution - Amazon CloudFront

Only the Organizations management account (or roles in that account) can call organizations:CreateAccount directly. When moving the Lambda function to a different (dedicated) account, the correct pattern is to perform cross-account role assumption into a role that resides in the management account and has tightly scoped Organizations permissions.

Option A describes exactly this:

Create an IAM role in the management account with only the required Organizations permissions (for example, organizations:CreateAccount and related read permissions).

Configure the trust policy on that role to allow it to be assumed by the Lambda execution role in the new account.

Update the Lambda code to call sts:AssumeRole into the management-account role before invoking the Organizations API.

This approach ensures that:

The Lambda function can create new accounts, but only via the management account.

The Lambda execution role in the dedicated account has no direct Organizations permissions; it only has permission to assume the specific role.

Option B is incorrect because “delegated administration for Organizations” in the generic sense is not how CreateAccount is exposed; account creation remains a management-account responsibility. Options C and D either misconfigure trust or introduce unnecessary Control Tower complexity. Cross-account assume-role from the dedicated account into the management account is the correct and least-privilege solution.

The correct answer is C. Allowing users to deploy CloudFormation stacks using AWS Service Catalog only and enforcing the use of a launch constraint is the best way to ensure that the internal business teams launch resources through pre-approved CloudFormation templates only. AWS Service Catalog is a service that enables organizations to create and manage catalogs of IT services that are approved for use on AWS. A launch constraint is a rule that specifies the role that AWS Service Catalog assumes when launching a product. By using a launch constraint, the DevOps engineer can control the permissions that the users have when launching a product. Using AWS Config rules to detect when resources have drifted from their expected state is the best way to automate the monitoring of the resources. AWS Config is a service that enables you to assess, audit, and evaluate the configurations of your AWS resources. AWS Config rules are custom or managed rules that AWS Config uses to evaluate whether your AWS resources comply with your desired configurations. By using AWS Config rules, the DevOps engineer can track the changes in the resources and identify any non-compliant resources.

Option A is incorrect because allowing users to deploy CloudFormation stacks using a CloudFormation service role only is not the best way to ensure that the internal business teams launch resources through pre-approved CloudFormation templates only. A CloudFormation service role is an IAM role that CloudFormation assumes to create, update, or delete the stack resources. By using a CloudFormation service role, the DevOps engineer can control the permissions that CloudFormation has when acting on the resources, but not the permissions that the users have when launching a stack. Therefore, option A does not prevent the users from launching resources that are not approved by the company. Using CloudFormation drift detection to detect when resources have drifted from their expected state is a valid way to monitor the resources, but it is not as automated and scalable as using AWS Config rules. CloudFormation drift detection is a feature that enables you to detect whether a stack’s actual configuration differs, or has drifted, from its expected configuration. To use this feature, the DevOps engineer would need to manually initiate a drift detection operation on the stack or the stack resources, and then view the drift status and details in the CloudFormation console or API.

Option B is incorrect because allowing users to deploy CloudFormation stacks using a CloudFormation service role only is not the best way to ensure that the internal business teams launch resources through pre-approved CloudFormation templates only, as explained in option A. Using AWS Config rules to detect when resources have drifted from their expected state is a valid way to monitor the resources, as explained in option C.

Option D is incorrect because enforcing the use of a template constraint is not the best way to ensure that the internal business teams launch resources through pre-approved CloudFormation templates only. A template constraint is a rule that defines the values or properties that users can specify when launching a product. By using a template constraint, the DevOps engineer can control the parameters that the users can provide when launching a product, but not the permissions that the users have when launching a product. Therefore, option D does not prevent the users from launching resources that are not approved by the company. Using Amazon EventBridge notifications to detect when resources have drifted from their expected state is a less reliable and consistent solution than using AWS Config rules. Amazon EventBridge is a service that enables you to connect your applications with data from a variety of sources. Amazon EventBridge can deliver a stream of real-time data from event sources, such as AWS services, and route that data to targets, such as AWS Lambda functions. However, to use this solution, the DevOps engineer would need to configure the event source, the event bus, the event rule, and the event target for each resource type that needs to be monitored, which is more complex and error-prone than using AWS Config rules.

https://docs.aws.amazon.com/cli/latest/reference/cloudformation/continue-update-rollback.html For a specified stack that is in the UPDATE_ROLLBACK_FAILED state, continues rolling it back to the UPDATE_ROLLBACK_COMPLETE state. Depending on the cause of the failure, you can manually fix the error and continue the rollback. By continuing the rollback, you can return your stack to a working state (the UPDATE_ROLLBACK_COMPLETE state), and then try to update the stack again.

The requirement is to immediately detect and terminate EC2 instances involved in cryptocurrency mining with the least development effort. Amazon GuardDuty is the AWS-native service specifically designed to detect malicious activities such as crypto-mining by continuously analyzing CloudTrail events, VPC Flow Logs, and DNS logs. GuardDuty includes managed threat intelligence and predefined findings like CryptoCurrency:EC2/BitcoinTool.B!DNS and CryptoCurrency:EC2/BitcoinTool.B!IP, which directly identify mining behavior without custom detection logic.

Option C leverages this built-in capability. Once GuardDuty is enabled, findings are automatically generated when mining activity is detected. These findings are sent to Amazon EventBridge in near real time. An EventBridge rule can filter for cryptocurrency-related findings and trigger an AWS Lambda function . The Lambda function can then identify the affected EC2 instance and terminate it or adjust the Auto Scaling group to replace it. This approach requires minimal custom code and no log parsing, scheduled jobs, or analytics pipelines.

Options A and B rely on custom log analysis, periodic execution, and maintaining lists of mining domains or IPs, which significantly increases complexity and response time. Option D uses AWS Security Hub, which aggregates findings from GuardDuty and other services but is not intended for immediate, low-latency remediation.

Therefore, Option C provides the fastest detection, immediate response, and lowest development overhead using AWS-managed threat detection services.

To meet the requirements, the DevOps engineer should do the following:

Turn on the Multi-AZ option on the Aurora cluster.

Update the application to use the Aurora cluster endpoint for write operations.

Update the Aurora cluster ' s reader endpoint for reads.

Turning on the Multi-AZ option will create a replica of the database in a different Availability Zone. This will ensure that the database remains available even if one of the Availability Zones is unavailable.

Updating the application to use the Aurora cluster endpoint for write operations will ensure that all writes are sent to both the primary and replica databases. This will ensure that the data is always consistent.

Updating the Aurora cluster ' s reader endpoint for reads will allow the application to read data from the replica database. This will improve the performance of the application during the maintenance window.

Option A is incorrect because creating an Amazon EventBridge rule that invokes an AWS Lambda function to query the applications on a 5-minute interval is not a valid solution. EventBridge rules can only trigger Lambda functions based on events, not on time intervals. Moreover, querying the applications on a 5-minute interval might incur unnecessary costs and network overhead, and might not detect performance issues in real time.

Option B is correct because creating an Amazon CloudWatch Synthetics canary that runs a custom script to query the applications on a 5-minute interval is a valid solution. CloudWatch Synthetics canaries are configurable scripts that monitor endpoints and APIs by simulating customer behavior. Canaries can run as often as once per minute, and can measure the latency and availability of the applications. Canaries can also send notifications to an Amazon SNS topic when they detect errors or performance issues1.

Option C is incorrect because creating an Amazon CloudWatch alarm that uses the AWS/ApplicationELB namespace RequestCountPerTarget metric is not a valid solution. The RequestCountPerTarget metric measures the number of requests completed or connections made per target in a target group2. This metric does not reflect the application response time, which is the requirement. Moreover, configuring the CloudWatch alarm to send a notification when the number of connections becomes greater than the configured number of threads that the application supports is not a valid way to measure the application performance, as it depends on the application design and implementation.

Option D is incorrect because creating an Amazon CloudWatch alarm that uses the AWS/ApplicationELB namespace RequestCountPerTarget metric is not a valid solution, for the same reason as option C. The RequestCountPerTarget metric does not reflect the application response time, which is the requirement. Moreover, configuring the CloudWatch alarm to send a notification when the average response time becomes greater than the longest response time that the application supports is not a valid way to measure the application performance, as it does not account for variability or outliers in the response time distribution.

S3 cross-Region replication (CRR) automatically replicates data between buckets across different AWS Regions. To enable CRR, you need to add a replication configuration to your source bucket that specifies the destination bucket, the IAM role, and the encryption type (optional). You also need to grant permissions to the IAM role to perform replication actions on both the source and destination buckets. Additionally, you can choose the destination storage class and enable additional replication options such as S3 Replication Time Control (S3 RTC) or S3 Batch Replication. https://medium.com/cloud-techies/s3-same-region-replication-srr-and-cross-region-replication-crr-34d446806bab https://aws.amazon.com/getting-started/hands-on/replicate-data-using-amazon-s3-replication/ https://docs.aws.amazon.com/AmazonS3/latest/userguide/replication.html

These are the possible causes for the AccessDenied error because they affect the permissions to access the S3 object from the EC2 instance. An S3 bucket policy is a resource-based policy that defines who can access the bucket and its objects, and what actions they can perform. An IAM role is an identity that can be assumed by an EC2 instance to grant it permissions to access AWS services and resources. If there is an error in the S3 bucket policy or the IAM role configuration, such as a missing or incorrect statement, condition, or principal, then the EC2 instance may not have the necessary permissions to download the object from the S3 bucket .

https://docs.aws.amazon.com/AmazonS3/latest/userguide/example-bucket-policies.html

https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/iam-roles-for-amazon-ec2.html

https://docs.aws.amazon.com/codedeploy/latest/userguide/deployment-groups.html

Amazon EC2 Image Builder is a service that automates the creation, management, and deployment of customized, secure, and up-to-date server images that are pre-installed with software and configuration settings tailored to meet specific IT standards. EC2 Image Builder simplifies the creation and maintenance of golden images, and makes it easy to generate images for multiple platforms, such as Amazon EC2 and on-premises. EC2 Image Builder also integrates with AWS Resource Access Manager, which allows you to share your images across accounts within your organization or with external AWS accounts. This solution meets the requirements of automating the tasks of updating the Linux AMIs, installing the Chef agent, and providing the images to the department’s accounts with the least management overhead. References:

Amazon EC2 Image Builder

Sharing EC2 Image Builder images

 Turn off cross-zone load balancing on the ALB ' s target group:

Cross-zone load balancing distributes traffic evenly across all registered targets in all enabled Availability Zones. Turning this off will ensure that each target group only handles requests from its respective Availability Zone.

To disable cross-zone load balancing:

Go to the Amazon EC2 console.

Navigate to Load Balancers and select the ALB.

Choose the Target Groups tab, select the target group, and then select the Group details tab.

Click on Edit and turn off Cross-zone load balancing.

 Use Amazon Route 53 Application Recovery Controller to start a zonal shift away from the Availability Zone:

Amazon Route 53 Application Recovery Controller provides the ability to control traffic flow to ensure high availability and disaster recovery.

By using Route 53 Application Recovery Controller, you can perform a zonal shift to redirect traffic away from the unhealthy Availability Zone.

To start a zonal shift:

Configure Route 53 Application Recovery Controller by creating a cluster and control panel.

Create routing controls to manage traffic shifts between Availability Zones.

Use the routing control to shift traffic away from the affected Availability Zone.

https://docs.aws.amazon.com/codedeploy/latest/userguide/troubleshooting-deployments.html#troubleshooting-skipped-lifecycle-events

https://aws.amazon.com/blogs/mt/automate-remediation-actions-for-amazon-ec2-notifications-and-beyond-using-ec2-systems-manager-automation-and-aws-health/

Create an Amazon EventBridge (Amazon CloudWatch Events) rule that matches an AWS Config evaluation result of NON_COMPLIANT for the restricted-ssh rule. Configure an input transformer for the EventBridge (CloudWatch Events) rule. Configure the EventBridge (CloudWatch Events) rule to publish a notification to the SNS topic. This approach uses Amazon EventBridge (previously known as Amazon CloudWatch Events) to filter AWS Config evaluation results based on the restricted-ssh rule and its compliance status (NON_COMPLIANT). An input transformer can be used to customize the information contained in the notification, such as the name and ID of the noncompliant security group. The EventBridge (CloudWatch Events) rule can then be configured to publish a notification to the SNS topic, which will notify the appropriate personnel in real-time.

Option A is incorrect because increasing the memory of the Lambda function does not address the root cause of the problem, which is that the Lambda function is not triggered by the S3 event source. Increasing the memory of the Lambda function might improve its performance or reduce its execution time, but it does not affect its invocation. Moreover, increasing the memory of the Lambda function might incur higher costs, as Lambda charges based on the amount of memory allocated to the function.

Option B is correct because creating a resource policy on the Lambda function to grant Amazon S3 the permission to invoke the Lambda function for the S3 bucket is a necessary step to configure an S3 event source. A resource policy is a JSON document that defines who can access a Lambda resource and under what conditions. By granting Amazon S3 permission to invoke the Lambda function, the company ensures that the Lambda function runs when a new object is created or an existing object is modified in the S3 bucket1.

Option C is incorrect because configuring an Amazon Simple Queue Service (Amazon SQS) queue as an On-Failure destination for the Lambda function does not help with triggering the Lambda function. An On-Failure destination is a feature that allows Lambda to send events to another service, such as SQS or Amazon Simple Notification Service (Amazon SNS), when a function invocation fails. However, this feature only applies to asynchronous invocations, and S3 event sources use synchronous invocations. Therefore, configuring an SQS queue as an On-Failure destination would have no effect on the problem.

Option D is incorrect because provisioning space in the /tmp folder of the Lambda function does not address the root cause of the problem, which is that the Lambda function is not triggered by the S3 event source. Provisioning space in the /tmp folder of the Lambda function might help with processing large files from the S3 bucket, as it provides temporary storage for up to 512 MB of data. However, it does not affect the invocation of the Lambda function.

 Ensure that the Amazon CloudWatch agent is installed on all EC2 instances:

The Amazon CloudWatch agent collects and logs metrics and sends them to Amazon CloudWatch.

To install the CloudWatch agent:

Download the CloudWatch agent package.

Install the agent on your EC2 instances.

Configure the agent to collect disk space metrics.

 Create an Amazon CloudWatch alarm to monitor available disk space on all EC2 instances Add the alarm as a safety control to the Systems Manager Automation task:

Create CloudWatch alarms to monitor the available disk space and trigger notifications or actions when the disk space falls below a defined threshold.

Add the CloudWatch alarm to the Systems Manager Automation task to halt or fail the task if disk space is insufficient.

To create the alarm:

Navigate to the CloudWatch console and create a new alarm.

Set the metric to monitor (e.g., disk space utilization).

Define the threshold and notification actions.

For pull through cache repositories, Amazon ECR now supports repository creation templates that can be applied to a registry prefix, such as /external . These templates define default settings, including encryption configuration with a specific KMS key , tag immutability, scan on push, and more. When new cache repositories are auto-created under that prefix, they inherit the template settings automatically.

In this scenario, existing external cache repositories are noncompliant because they use SSE-S3. The company can delete those repositories (removing the noncompliant caches) and configure an ECR repository creation template for the /external prefix that specifies the required customer managed KMS key. As new images are pulled, ECR recreates the cache repositories under that prefix with KMS encryption using the specified key , guaranteeing compliance going forward.

Option A (AWS Config) would only detect noncompliance after creation and cannot enforce encryption at creation time. Option C (SCP) cannot directly control repository encryption properties. Option D misuses EventBridge; KMS cannot be a “target” that retroactively encrypts repositories.

Therefore, using an ECR repository creation template with the desired KMS key is the correct, automatic, and secure solution.

 Impact of Removing FullAWSAccess and Adding Policy for EC2 Actions:

The FullAWSAccess policy allows all actions on all resources by default. Removing this policy from the Department OU will limit the permissions that accounts within this OU inherit from the parent OU.

Adding a policy that allows only Amazon EC2 API operations will restrict the permissions to EC2 actions only.

 Permissions of Administrative IAM Roles:

The administrative IAM roles in the Engineering OU have the AdministratorAccess policy attached, which grants full access to all AWS services and resources.

Since SCPs are restrictions that apply at the organizational level, removing FullAWSAccess and replacing it with a policy allowing only EC2 actions means that for all accounts in the Engineering OU:

They will have full access to EC2 actions due to the new SCP.

They will be restricted in other actions that are not covered by the SCP, hence, non-EC2 API actions will be denied.

 Conclusion:

All API actions on EC2 resources will be allowed.

All other API actions will be denied due to the absence of a broader allow policy.