DOP-C02 Resilient Cloud Solutions Practice Test 11 — 15 Questions

Question 1

A company uses AWS CloudFormation to deploy infrastructure. They want to ensure that if a stack update fails, the stack is automatically rolled back to the last known good state. However, they also want to preserve any resources that were created successfully before the failure. Which CloudFormation stack policy should be used?

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

Accepted Answer

Use a stack policy that allows all actions except delete.. A stack policy that denies delete actions prevents CloudFormation from deleting resources that were created successfully before failure during a rollback. When a stack update fails, CloudFormation rolls back to the previous state, which typically involves deleting or modifying resources that were created or modified during the failed update. By denying delete actions on specific resources, those resources are preserved even if the overall stack rolls back. Option B (deny update) is incorrect because denying update only prevents modifications, but resources can still be deleted during rollback. Option A is incorrect because a creation policy with a resource signal is used to control when instances are considered created, not for rollback preservation. Option D is incorrect because RollbackConfiguration with a monitoring time is used for rollout monitoring, not for preserving resources during rollback.

Answer

Define a creation policy with a resource signal.

Answer

Use a stack policy that denies update actions on resources that should be preserved.

Answer

Set the RollbackConfiguration property with a monitoring time.

Question 2

An organization runs a critical application on Amazon EC2 instances in an Auto Scaling group behind an Application Load Balancer. The application requires that all traffic be encrypted in transit. The security team mandates the use of TLS 1.2 or higher and specific ciphers. What is the MOST efficient way to enforce this requirement?

Accepted Answer

Configure the ALB with a security policy that enforces TLS 1.2 and the required ciphers.. The Application Load Balancer (ALB) supports predefined security policies that enforce TLS version and cipher requirements at the load balancer level, providing centralized control. Option D is correct because configuring the ALB with a security policy that mandates TLS 1.2 and specific ciphers meets the requirement efficiently without modifying individual instances. Option A is incorrect because a Network Load Balancer (NLB) with TLS listeners does not offer the same granular security policy options as ALB and is less efficient for this requirement. Option B is incorrect because CloudFront is a CDN service; placing it in front of the ALB does not directly enforce TLS settings on the ALB itself and adds unnecessary complexity. Option C is incorrect because installing self-signed certificates on each EC2 instance is inefficient, not centralized, and does not enforce consistent TLS version and cipher requirements across all traffic.

Answer

Use a Network Load Balancer with TLS listeners and target groups.

Answer

Place a CloudFront distribution in front of the ALB and configure the origin protocol policy.

Answer

Install a self-signed certificate on each EC2 instance and configure the web server.

Question 3

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 (option A) is the correct choice because it automatically provisions and maintains a synchronous standby replica in a different Availability Zone, providing automatic failover if the underlying hardware fails. Deletion protection (option B) prevents accidental deletion but does not handle recovery. Read replicas (option C) are used for read scaling and do not provide automatic failover. Automated backups (option D) enable point-in-time recovery but do not automatically recover from hardware failures.

Answer

Deletion protection.

Answer

Read replicas in a different Region.

Answer

Automated backups with a retention period of 35 days.

Question 4

Which TWO strategies can be used to improve the resilience of an application running on Amazon ECS with Fargate? (Select TWO.)

Accepted Answer

Configure the ECS service to place tasks in multiple Availability Zones.. Configuring the ECS service to place tasks in multiple Availability Zones distributes the application across physically separate data centers, so if one AZ fails, the tasks in other AZs continue to run. Option D is correct because implementing a circuit breaker pattern for downstream dependencies prevents cascading failures by detecting faults and failing fast, allowing the system to recover gracefully. Option A is incorrect; using a single subnet for all tasks typically places them in a single Availability Zone, reducing fault tolerance. Option C is incorrect; increasing task memory reservation helps handle peak load but does not improve resilience against failures. Option E is incorrect; scheduled scaling adjusts capacity based on historical patterns and does not handle unexpected spikes or failures.

Answer

Use a single subnet for all tasks to simplify networking.

Answer

Increase the task memory reservation to handle peak load.

Answer

Use scheduled scaling to adjust task count based on historical patterns.

Question 5

Which THREE components are required to implement a global application that can withstand the failure of an entire AWS Region? (Select THREE.)

Accepted Answer

Amazon CloudFront with multiple origins and origin failover.. To implement a global application resilient to an entire AWS Region failure, you need DNS failover, multi-region data replication, and edge caching with origin failover. Amazon Route 53 with health checks and failover routing policy (E) detects region outages and directs traffic to healthy regions. Amazon CloudFront with multiple origins and origin failover (B) provides edge caching and can switch to a secondary origin if the primary fails. Amazon DynamoDB Global Tables (C) replicates data across regions for multi-region writes and reads. Option A (ALB in primary region) is regional and cannot handle cross-region failover. Option D (RDS Single-AZ) lacks multi-region replication and is not resilient.

Answer

An Application Load Balancer in the primary Region.

Answer

Amazon RDS with a single-AZ deployment.

Question 6

Which TWO actions can help protect against accidental deletion of an Amazon S3 bucket? (Select TWO.)

Accepted Answer

Enable MFA Delete on the bucket.. Options C (MFA Delete) and E (bucket policy denying s3:DeleteBucket) are correct. MFA Delete adds an extra layer of protection by requiring multi-factor authentication to permanently delete object versions and change the versioning state, which helps prevent accidental deletions. A bucket policy that explicitly denies the s3:DeleteBucket action directly prevents accidental bucket deletion. Option A is incorrect because versioning alone does not prevent bucket deletion; it protects object versions. Option B is incorrect because CloudTrail provides auditing of delete events but does not prevent them. Option D is incorrect because a lifecycle policy automatically deletes objects, increasing the risk of accidental deletion rather than protecting against it.

Answer

Enable versioning on the bucket.

Answer

Enable AWS CloudTrail to log delete events.

Answer

Configure a lifecycle policy to expire objects.

Question 7

A company runs a critical web application on Amazon EC2 instances behind an Application Load Balancer (ALB). The application frequently experiences high latency during peak hours. The DevOps team needs to implement a solution that automatically adds capacity based on demand and reduces cost during off-peak hours. Which combination of AWS services should the team use?

Accepted Answer

Use an AWS Auto Scaling group with target tracking scaling policies based on the ALB's request count per target, and attach it to the ALB target group.. Target tracking scaling policies allow the Auto Scaling group to automatically adjust capacity based on a specific metric, such as ALB request count per target, which directly reflects the load on each instance. This ensures that capacity is added during high latency periods and removed during off-peak hours, optimizing both performance and cost. The ALB target group integration ensures that new instances are automatically registered and start receiving traffic.

Answer

Use an AWS Auto Scaling group with scheduled scaling policies that add instances during known peak hours and remove them during off-peak hours.

Answer

Implement Amazon Route 53 weighted routing policies to distribute traffic to multiple ALBs, each fronting a fixed set of EC2 instances.

Answer

Use an AWS Auto Scaling group with simple scaling policies based on CPU utilization and attach it to the ALB target group.

Question 8

A company's DevOps team is designing a multi-region disaster recovery solution for a stateless web application. The application runs on Amazon EC2 instances behind an Application Load Balancer (ALB) in the us-east-1 region. The team needs to fail over to a secondary region (us-west-2) with minimal downtime in case of a regional outage. Which AWS service should the team use to route traffic to the healthy region?

Accepted Answer

Amazon Route 53 with a failover routing policy and health checks on the primary ALB.. AWS Global Accelerator with endpoint groups in both regions automatically routes traffic based on health checks, allowing failover to the healthy region. The current explanation only justifies A and does not correctly dismiss C.

Answer

Elastic Load Balancing (ELB) cross-zone load balancing across regions.

Answer

Amazon CloudFront with a multi-origin setup and origin failover.

Question 9

A company is running a production database on Amazon RDS for PostgreSQL with Multi-AZ deployment. The database experiences a failover due to an AZ outage. What happens to the existing database connections during the failover?

Accepted Answer

Existing connections are dropped, and applications must reconnect to the new primary using the same endpoint.. During a Multi-AZ failover, RDS automatically updates the DNS record to point to the standby, but existing connections to the primary are dropped and must be re-established. Option A is wrong because connections are not preserved. Option B is wrong because Multi-AZ automatically fails over without manual promotion. Option D is wrong because the CNAME record does not change; it's a DNS update.

Answer

Existing connections are automatically redirected to the standby without interruption.

Answer

The RDS endpoint IP address changes, and the application must update its configuration.

Answer

The primary DB instance is promoted to standby and connections remain active.

Question 10

A company is designing a highly available architecture for a web application. The application runs on Amazon EC2 instances in an Auto Scaling group across three Availability Zones. The instances are behind an Application Load Balancer (ALB). Which additional step should the team take to ensure that traffic is evenly distributed across all healthy instances in all Availability Zones?

Accepted Answer

Enable cross-zone load balancing on the ALB.. By default, ALB distributes traffic evenly across AZs, but cross-zone load balancing must be enabled to distribute traffic evenly across all instances regardless of AZ. Option A is wrong because Route 53 weighted routing is not needed for internal load balancing; the ALB already distributes traffic across AZs. Option B is wrong because configuring health checks to mark instances unhealthy based on AZ instance count would not help with even distribution and could cause unnecessary failures. Option D is wrong because the least outstanding requests routing algorithm optimizes for request queue depth but does not enable cross-zone load balancing; cross-zone load balancing must be explicitly enabled.

Answer

Use Amazon Route 53 weighted routing policy to distribute traffic to each AZ.

Answer

Configure health checks on the target group to mark instances as unhealthy if they are in an AZ with fewer instances.

Answer

Configure the ALB to use least outstanding requests routing algorithm.

Question 11

A company is running a stateful web application on Amazon EC2 instances. The application stores session data locally on the instance. The company wants to make the application stateless and improve resilience. The DevOps team decides to use Amazon ElastiCache for Redis to store session data. What additional step should the team take to ensure that the session data is highly available?

Accepted Answer

Enable ElastiCache for Redis cluster mode with automatic failover across multiple Availability Zones.. Enabling ElastiCache for Redis cluster mode with automatic failover across multiple Availability Zones ensures that if the primary node fails, a read replica in another AZ is promoted, providing high availability for session data. Option A is wrong because Multi-AZ for standard Redis provides automatic failover but does not include the partition tolerance and scalability benefits of cluster mode; for session data that needs high availability and scalability, cluster mode is recommended. Option B is wrong because a single node offers no redundancy; relying on application reconnection does not guarantee data availability during node failure. Option D is wrong because backing up to S3 provides durability but not automatic failover; during a failure, you would need to restore from backup, which is not automatic and incurs downtime.

Answer

Deploy ElastiCache for Redis in a Multi-AZ configuration with automatic failover.

Answer

Use a single ElastiCache for Redis node and rely on the application to reconnect if the node fails.

Answer

Configure ElastiCache for Redis to back up session data to Amazon S3 every 5 minutes.

Question 12

A company runs a microservices application on Amazon EKS. The application's frontend service needs to communicate with the backend service. The DevOps team wants to implement service-to-service authentication using AWS IAM. Which method should the team use?

Accepted Answer

Use IAM roles for service accounts (IRSA) to associate an IAM role with each service's Kubernetes service account.. IAM roles for service accounts (IRSA) allows each Kubernetes service account to assume an IAM role with fine-grained permissions, enabling secure service-to-service authentication without managing long-lived credentials. The frontend service can use its associated IAM role to sign AWS API requests (e.g., STS AssumeRole) to authenticate to the backend service, which validates the role via IAM policies. This approach integrates natively with EKS and follows AWS best practices for workload identity.

Answer

Configure the backend service as an Amazon RDS database with IAM database authentication.

Answer

Use AWS App Mesh with mTLS for authentication between services.

Answer

Create an IAM user with access keys and store them as Kubernetes secrets.

Question 13

A company has an Amazon S3 bucket that stores critical data. The company wants to protect the data from accidental deletion and ensure that even the root user cannot delete the bucket. Which S3 feature should the company enable?

Accepted Answer

S3 Object Lock with compliance retention mode.. An S3 bucket policy that explicitly denies s3:DeleteBucket for all principals prevents any user, including the root user, from deleting the bucket. This is because resource-based policies such as bucket policies are evaluated for all principals, including the root user. S3 Object Lock with compliance mode prevents object deletion but does not directly prevent bucket deletion; while it makes the bucket non-empty, bucket deletion is a separate operation that can still be attempted. Versioning with MFA delete only protects object versions, and lifecycle policies expire noncurrent versions, neither preventing bucket deletion.

Answer

S3 bucket policy that denies s3:DeleteBucket for all principals.

Answer

S3 bucket versioning with MFA delete.

Answer

S3 bucket versioning with lifecycle policy to expire noncurrent versions.

Question 14

A company runs a critical application on Amazon EC2 instances in an Auto Scaling group. The application generates logs that are sent to Amazon CloudWatch Logs. The DevOps team needs to configure a metric filter to monitor for error patterns and trigger an alarm when the error rate exceeds 5% of total requests over a 5-minute period. Which TWO steps should the team take? (Choose TWO.)

Accepted Answer

Create a metric filter on the log group to count occurrences of the error pattern.. To achieve the monitoring goal, the team must first create a metric filter on the existing log group (Option B). This filter defines the error pattern to count and emits a custom metric for the error count. Then, they need to create a CloudWatch alarm that uses a math expression to calculate the error rate by dividing the error count metric by a total request count metric (or by using the same log group with another filter for total requests) and triggers when the rate exceeds 5% over 5 minutes (Option E). Option A is not required because the log group already exists. Option C is incorrect because a subscription filter would forward logs to Lambda, but the requirement is to use metric filters and alarms. Option D is incorrect because the metric is automatically created by the metric filter; you do not need to manually create a separate metric.

Answer

Create a CloudWatch Logs log group for the error metric.

Answer

Create a CloudWatch Logs subscription filter to stream errors to a Lambda function that calculates the error rate.

Answer

Create a CloudWatch metric for the error count.

Question 15

A company is deploying a web application on Amazon ECS with Fargate. The application consists of a frontend service and a backend service. The DevOps team needs to ensure that the frontend service can communicate with the backend service securely without exposing the backend to the internet. Which THREE steps should the team take? (Choose THREE.)

Accepted Answer

Deploy the backend service in a private subnet with no internet access.. Deploying the backend service in a private subnet with no internet access ensures that the backend is not reachable from the internet, which is a fundamental security requirement. In Amazon ECS with Fargate, tasks in a private subnet use an elastic network interface (ENI) with no public IP address, and outbound traffic can be routed through a NAT gateway if needed, but inbound traffic from the internet is blocked. This isolates the backend from direct external exposure while still allowing communication from the frontend service within the same VPC.

Answer

Deploy the backend service in a public subnet with an internet-facing Application Load Balancer.

Answer

Use an internet-facing Network Load Balancer for the backend service.