DOP-C02 Timed Practice Test 3 — 10 Questions

Question 1

A developer wants to use AWS CloudFormation to create an Amazon RDS DB instance. The template includes a DB instance resource. Which property is required for the DB instance to be created successfully?

Accepted Answer

DBInstanceClass and Engine. In AWS CloudFormation, when creating an Amazon RDS DB instance using the AWS::RDS::DBInstance resource, the only truly required properties are DBInstanceClass (the compute and memory capacity) and Engine (the database engine, e.g., MySQL, PostgreSQL). These two properties are mandatory in the CloudFormation resource specification; without them, the template will fail validation. All other properties, such as AllocatedStorage, DBInstanceIdentifier, MasterUsername, and MasterUserPassword, have default behaviors or can be omitted under certain conditions (e.g., AllocatedStorage defaults to 20 GB for some engines, and MasterUsername/MasterUserPassword are not required if you use a snapshot or a source DB instance).

Answer

AllocatedStorage

Answer

DBInstanceIdentifier

Answer

MasterUsername and MasterUserPassword

Question 2

A company runs a critical web application on Amazon EC2 instances behind an Application Load Balancer (ALB). The application uses an Amazon RDS for MySQL Multi-AZ DB instance for data storage. During an AWS infrastructure event, the primary Availability Zone (AZ) becomes unavailable, and the application experiences downtime. The RDS Multi-AZ failover completes automatically, but the application takes several minutes to reconnect. Which combination of actions would MOST reduce the recovery time for the application during such an event?

Accepted Answer

Use an RDS proxy (Amazon RDS Proxy) to pool and share database connections, and ensure the application uses the RDS cluster endpoint.. Option B is correct because Amazon RDS Proxy maintains a warm connection pool to the database, so when the RDS Multi-AZ failover occurs, the proxy automatically reconnects to the new primary DB instance without requiring the application to re-establish connections. This eliminates the connection storm and the several-minute delay caused by the application's connection retry logic. By using the RDS cluster endpoint (which points to the proxy), the application benefits from seamless failover and reduced latency during the DNS propagation of the new primary.

Answer

Place all EC2 instances in a single AZ and use an Amazon Route 53 health check to reroute traffic to a standby environment in another AZ.

Answer

Deploy the RDS instance as a Single-AZ instance in the same AZ as the primary EC2 instances, and use read replicas for failover.

Answer

Configure an Application Load Balancer in front of the RDS instance to distribute connections across AZs.

Question 3

A company is designing a disaster recovery (DR) strategy for a stateless web application deployed on Amazon ECS with Fargate. The application is fronted by an Application Load Balancer (ALB) and uses Amazon ElastiCache for Redis for session state. The primary region is us-east-1. The DR plan requires a Recovery Point Objective (RPO) of 15 minutes and a Recovery Time Objective (RTO) of 30 minutes. Which solution meets these requirements with the LEAST operational overhead?

Accepted Answer

Deploy an ALB with a warm standby ECS service in us-west-2. Use Route 53 health checks to route traffic to the secondary region if primary fails. Use ElastiCache Global Datastore for Redis to replicate data across regions.. Option A is correct because it uses ElastiCache Global Datastore for Redis, which provides cross-region replication with an RPO of seconds (well within 15 minutes) and automatic failover, minimizing operational overhead. The warm standby ECS service in us-west-2 with Route 53 health checks allows traffic to be redirected within the 30-minute RTO without manual intervention, as the ALB and ECS service are pre-provisioned.

Answer

Deploy an Active-Active configuration across two AWS regions using Route 53 latency routing. Use ElastiCache for Redis Global Datastore with multi-region writes.

Answer

Deploy a Pilot Light environment in us-west-2 with a scaled-down ECS service and Redis cluster. Use Route 53 DNS failover. On disaster, scale up the ECS service and promote the Redis cluster.

Answer

Use Amazon ECS with Fargate in us-east-1 only, and schedule daily snapshots of ElastiCache for Redis. In case of disaster, restore the snapshot in a new region and update DNS.

Question 4

A company runs a containerized microservices application on Amazon EKS. The application includes a critical service that processes real-time financial transactions. This service must be highly available and resilient to node failures. The current setup uses a Deployment with 3 replicas and a ClusterIP service. During a recent node failure, the application experienced a brief period of unavailability. Which action should the DevOps engineer take to improve resilience without changing the underlying infrastructure?

Accepted Answer

Configure a PodDisruptionBudget with a maxUnavailable of 1, and add pod anti-affinity rules to spread pods across different nodes.. Option C is correct because a PodDisruptionBudget with maxUnavailable=1 ensures that at most one pod is unavailable during voluntary disruptions, while pod anti-affinity rules force the scheduler to distribute pods across different nodes. This combination prevents a single node failure from taking down all replicas, maintaining service availability without altering the underlying infrastructure.

Answer

Change the service type from ClusterIP to NodePort and configure an external load balancer.

Answer

Increase the number of replicas to 10 and use a node selector to schedule all pods on the largest instance type.

Answer

Enable HorizontalPodAutoscaler with a target CPU utilization of 50% to automatically scale the Deployment.

Question 5

A company runs a stateful web application on EC2 instances behind a Network Load Balancer (NLB) in a single Availability Zone. The application stores session state locally on the instance. The company wants to achieve high availability across multiple AZs with minimal application changes. What should the DevOps engineer do?

Accepted Answer

Replace the NLB with an ALB and enable sticky sessions (session affinity) using the ALB's cookie.. Option D is correct because replacing the NLB with an ALB and enabling sticky sessions (session affinity) using the ALB's cookie allows the stateful web application to maintain session state across multiple AZs without modifying the application code. The ALB generates a cookie (AWSALB) that binds a client's session to a specific target instance, ensuring subsequent requests from the same client are routed to the same EC2 instance. This achieves high availability across AZs with minimal changes, as the application continues to store session state locally on the instance.

Answer

Add more AZs and configure the NLB with cross-zone load balancing.

Answer

Replace the NLB with an ALB and use ElastiCache for session storage.

Answer

Use a Multi-AZ RDS instance to store session state.

Question 6

A DevOps engineer needs to restrict access to an S3 bucket so that only users from a specific AWS account can read objects. Which TWO methods can achieve this?

Accepted Answer

Create an IAM role in the source account with read access to the bucket, and allow users in that account to assume the role.. Options A and D are correct. Bucket policy with condition can restrict to specific source account. IAM roles in the source account can grant cross-account access. Option B (pre-signed URLs) works for individual objects but not as a general restriction. Option C (block public access) does not restrict to a specific account. Option E (ACL) is legacy and less secure.

Answer

Enable S3 Block Public Access on the bucket.

Answer

Generate pre-signed URLs for each object and distribute them only to users in the target account.

Answer

Set a bucket ACL that grants read access to the target account's canonical ID.

Question 7

A company runs a critical web application on EC2 instances behind an Application Load Balancer (ALB) with Auto Scaling. During a recent traffic spike, the application became unavailable for 10 minutes. Analysis shows that the ALB's healthy host count dropped to zero because the instances failed health checks due to high CPU load. What is the MOST effective design change to improve resilience during future traffic spikes?

Accepted Answer

Use predictive scaling with a scheduled scaling policy for known peak times.. Predictive scaling uses historical traffic data to forecast future demand and proactively adjust capacity before a spike occurs. This prevents the CPU from reaching critical levels that cause health check failures, ensuring the ALB always has healthy hosts. Scheduled scaling alone would not adapt to unexpected spikes, but predictive scaling combined with dynamic scaling provides both proactive and reactive resilience.

Answer

Increase the instance size to handle higher load.

Answer

Configure step scaling policies based on CPU utilization.

Answer

Set a higher CPU threshold for health checks.

Question 8

A company's application runs on EC2 instances in a single Availability Zone. The operations team wants to improve resilience without redesigning the application. Which action is the MOST effective?

Accepted Answer

Deploy EC2 instances across multiple Availability Zones using an Auto Scaling group.. Deploying EC2 instances across multiple Availability Zones (AZs) using an Auto Scaling group is the most effective action because it eliminates the single point of failure at the AZ level. If one AZ experiences an outage, the Auto Scaling group automatically launches replacement instances in the remaining healthy AZs, ensuring application availability without requiring any application-level changes. This directly addresses the goal of improving resilience by leveraging AWS's fault-isolated infrastructure.

Answer

Use a larger instance type to handle more traffic.

Answer

Enable EC2 Auto Recovery to automatically restart the instance if it fails.

Answer

Place the instance in a placement group to ensure low latency.

Question 9

A company uses a third-party backup solution to back up its EC2 instances daily. The backups are stored in an S3 bucket with default settings. The company wants to ensure that backups are protected from accidental deletion and are available for at least one year. Which combination of S3 features should the DevOps engineer implement?

Accepted Answer

Enable S3 Object Lock with Governance mode and a retention period of 365 days, and set a lifecycle policy to transition to S3 Glacier Deep Archive after 30 days.. Option D is correct because S3 Object Lock with Governance mode prevents objects from being deleted or overwritten by any user (including the root user) for the specified retention period of 365 days, meeting the one-year availability requirement. The lifecycle policy to transition to S3 Glacier Deep Archive after 30 days reduces storage costs while still keeping the data accessible for retrieval within 12 hours, which is acceptable for backup retention. This combination ensures immutability and cost-effective long-term storage.

Answer

Enable MFA Delete and set a lifecycle policy to transition to S3 Glacier after 30 days.

Answer

Enable versioning and set a lifecycle policy to expire noncurrent versions after 365 days.

Answer

Enable cross-Region replication to a bucket with versioning enabled.

Question 10

A company runs a microservices application on Amazon ECS with Fargate. The application includes a service that processes orders and stores them in an RDS PostgreSQL database. The company wants to ensure that the order service is resilient to AZ failures and can handle a sudden increase in order volume. Which TWO actions should the DevOps engineer take? (Choose TWO.)

Accepted Answer

Deploy the RDS instance in a Multi-AZ configuration.. Option C is correct because deploying the RDS instance in a Multi-AZ configuration provides automatic failover to a standby replica in a different Availability Zone, ensuring database resilience to AZ failures. Option D is correct because configuring the ECS service to run tasks in multiple Availability Zones distributes the order processing workload across AZs, improving both fault tolerance and scalability during sudden traffic spikes.

Answer

Increase the CPU and memory limits for the ECS task definition.

Answer

Place an Amazon CloudFront distribution in front of the order service.

Answer

Use RDS Proxy to manage database connections.