SOA-C02 Reliability and Business Continuity Practice Test 7 — 15 Questions

Question 1

Which THREE measures can be used to improve the recovery time objective (RTO) for a database running on Amazon RDS? (Choose three.)

Accepted Answer

Use a read replica and promote it during a failure.. A read replica can be promoted to a primary database instance during a failure, which reduces RTO because the replica is already up and running with a synchronized copy of the data. This avoids the time needed to restore from a backup or snapshot, making it a fast failover option for read-heavy workloads.

Answer

Enable deletion protection.

Answer

Create manual snapshots daily.

Question 2

Which TWO steps should a SysOps administrator take to ensure data durability for an Amazon S3 bucket that stores critical documents? (Choose two.)

Accepted Answer

Enable S3 Versioning.. S3 Versioning (B) protects against accidental deletion and overwrites by preserving every version of an object, including deletions as delete markers. This ensures data durability by allowing recovery of previous versions. Cross-Region Replication (E) provides durability by asynchronously replicating objects to a different AWS region, protecting against region-wide failures.

Answer

Enable default encryption with SSE-S3.

Answer

Use S3 Transfer Acceleration.

Answer

Enable MFA Delete.

Question 3

A company runs a web application on EC2 instances behind an Application Load Balancer. The database is an RDS MySQL instance with Multi-AZ enabled. The application experiences intermittent 5xx errors that correlate with database failover events. What is the MOST likely cause and solution?

Accepted Answer

Enable DNS caching with a low TTL in the application and use the RDS instance endpoint with a retry mechanism.. During an RDS Multi-AZ failover, the DNS record for the primary instance endpoint is updated to point to the standby instance. If the application caches the old DNS resolution with a high TTL, it continues to send connections to the unreachable primary, causing 5xx errors. Enabling DNS caching with a low TTL (e.g., 5 seconds) and implementing a retry mechanism ensures the application quickly resolves the new endpoint and reconnects, minimizing downtime.

Answer

Configure the application to use the RDS reader endpoint.

Answer

Use a read replica to offload read traffic and reduce failover impact.

Answer

Increase the database connection pool size to handle retries.

Question 4

A company uses AWS Backup to back up its Amazon EFS file system daily. The backup retention policy is set to 30 days. Recently, a user accidentally deleted a critical directory. The company wants to restore the directory as it existed 2 days ago. What is the MOST cost-effective and quickest way to achieve this?

Accepted Answer

Restore the backup from 2 days ago to a new EFS file system, then copy the directory to the original file system.. AWS Backup creates point-in-time snapshots of EFS file systems. Restoring a backup from 2 days ago to a new EFS file system allows you to mount that new file system, copy the specific directory back to the original file system, and then delete the temporary file system. This is the most cost-effective and quickest approach since it avoids moving data to on-premises servers and uses native AWS services without additional replication costs.

Answer

Use the EFS console to recover the directory from the .Trash folder.

Answer

Enable EFS replication to another region and then fail back.

Answer

Use AWS Backup to restore the entire file system to an on-premises server, then copy the directory back.

Question 5

A SysOps administrator needs to ensure that an Amazon S3 bucket can withstand the loss of an entire AWS Availability Zone. What is the SIMPLEST configuration to meet this requirement?

Accepted Answer

Use S3 Standard storage class.. S3 Standard automatically stores objects across a minimum of three Availability Zones (AZs) within the same AWS Region. This design ensures that the bucket can withstand the loss of an entire AZ without any additional configuration, making it the simplest option to meet the requirement.

Answer

Enable cross-region replication to a bucket in another Region.

Answer

Use S3 One Zone-IA storage class.

Answer

Enable MFA Delete on the bucket.

Question 6

A company runs a stateless web application on EC2 instances in an Auto Scaling group across multiple Availability Zones. The application experiences increased latency during peak hours. The SysOps administrator needs to improve the application's performance and reliability. Which action should be taken?

Accepted Answer

Increase the maximum instance count in the Auto Scaling group.. Increasing the maximum instance count allows the Auto Scaling group to launch more EC2 instances during peak hours, distributing the load across more resources and reducing latency. This directly improves both performance (by handling more requests) and reliability (by maintaining capacity under increased demand).

Answer

Use larger EC2 instance types instead of smaller ones.

Answer

Reduce the Auto Scaling group's cooldown period to scale out faster.

Answer

Change the scaling metric from CPU utilization to memory utilization.

Question 7

A company has a production RDS for PostgreSQL instance with Multi-AZ enabled. During a recent failover test, the application experienced a 5-minute downtime. The company requires that failover be completed within 2 minutes. Which action should be taken to meet this requirement?

Accepted Answer

Configure an RDS Proxy in front of the database.. RDS Proxy reduces failover time by maintaining database connections and connection pooling, allowing the application to reconnect quickly without waiting for DNS propagation or new connection setup. In a Multi-AZ failover, RDS Proxy can typically complete failover in under 60 seconds, meeting the 2-minute requirement by minimizing connection disruption.

Answer

Migrate the database to Amazon Aurora with Multi-AZ.

Answer

Enable automated backups with a short retention period.

Answer

Increase the DB instance class to a larger size.

Question 8

A company uses Amazon Route 53 for DNS resolution. The company wants to ensure that if a web server becomes unhealthy, traffic is automatically routed to a healthy server in another Availability Zone. Which routing policy should be used?

Accepted Answer

Failover routing policy. The Failover routing policy (D) is correct because it is specifically designed to route traffic to a primary resource (e.g., a web server) and automatically redirect to a secondary resource in a different Availability Zone when health checks fail. Route 53 uses health checks to monitor the primary endpoint; if the primary becomes unhealthy, it returns the secondary record in DNS responses, ensuring automatic failover.

Answer

Latency routing policy

Answer

Weighted routing policy

Answer

Geolocation routing policy

Question 9

A SysOps administrator is designing a disaster recovery strategy for a critical application that runs on EC2 instances. The application data is stored on EBS volumes. The recovery point objective (RPO) is 15 minutes, and the recovery time objective (RTO) is 1 hour. Which solution meets these requirements MOST cost-effectively?

Accepted Answer

Take EBS snapshots every 15 minutes and copy them to another Region using cross-region snapshot copy.. Taking EBS snapshots every 15 minutes and using cross-region snapshot copy meets the 15-minute RPO and 1-hour RTO while being the most cost-effective. EBS snapshots are incremental, storing only changed blocks, which minimizes storage costs compared to full AMIs. Cross-region snapshot copy ensures data is available in another Region for recovery within the RTO.

Answer

Use AWS CloudEndure to continuously replicate the EC2 instances to another Region.

Answer

Use AWS Backup to back up the application data to Amazon S3 every 15 minutes.

Answer

Take hourly AMIs of the instances and copy them to another Region.

Question 10

A company runs a critical application on EC2 instances in an Auto Scaling group. The application stores state information locally on the instance. The SysOps administrator needs to ensure that if an instance fails, the state is not lost. What should the administrator do?

Accepted Answer

Move the state data to an external data store such as ElastiCache or RDS.. Moving state data to an external data store like ElastiCache or RDS decouples the state from the EC2 instance, making the application stateless. If an instance fails, the state persists in the external store and can be accessed by a new instance. Option B is incorrect because while setting 'DeleteOnTermination' to false preserves the EBS volume, it requires reattaching the volume to a new instance, which introduces latency and complexity, and the state may be stale. Option C is incorrect because instance store volumes are ephemeral and data is lost on instance stop/termination. Option D is incorrect because Amazon SQS is a message queuing service, not designed for state storage; it provides at-least-once delivery but does not offer the durability or consistency needed for critical state data.

Answer

Attach an EBS volume and set the 'DeleteOnTermination' flag to false.

Answer

Use instance store volumes for the state data.

Answer

Use Amazon SQS to store the state data.

Question 11

A company has an application that runs on EC2 instances behind an Application Load Balancer. The application uses an RDS Multi-AZ database. The company wants to ensure that the application remains available during a database failover. What should the SysOps administrator do?

Accepted Answer

Ensure the application retries database connections during failover.. During an RDS Multi-AZ failover, the database DNS record is updated to point to the standby instance, which can take up to 60 seconds. Existing connections are dropped, so the application must implement connection retry logic with exponential backoff to re-establish connections to the new primary. Without retries, the application will fail to serve requests until the database is reachable again, breaking availability.

Answer

Create a read replica of the database to offload read traffic.

Answer

Increase the EC2 instance size to handle the load.

Answer

Enable termination protection on the EC2 instances.

Question 12

A company is designing a highly available architecture for a web application using AWS services. Which TWO actions should the SysOps administrator take to improve reliability? (Choose TWO.)

Accepted Answer

Use an Auto Scaling group with an Elastic Load Balancer.. An Auto Scaling group combined with an Elastic Load Balancer automatically distributes incoming traffic across healthy EC2 instances and replaces any failed instances, ensuring the application remains available even during instance failures or traffic spikes. This architecture is a core AWS best practice for building highly available and resilient web applications.

Answer

Use a single large EC2 instance to eliminate complexity.

Answer

Use a single NAT gateway for outbound traffic.

Answer

Store application data on a single EBS volume.

Question 13

A company wants to protect its data in Amazon S3 from accidental deletion. Which TWO methods should the SysOps administrator use? (Choose TWO.)

Accepted Answer

Enable S3 Versioning on the bucket.. Enabling S3 Versioning preserves all versions of an object, including overwrites and deletes. When versioning is enabled, a delete operation does not permanently remove the object; instead, it adds a delete marker, allowing the object to be restored by removing the marker. This directly protects against accidental deletion.

Answer

Set up cross-Region replication.

Answer

Enable S3 Transfer Acceleration.

Answer

Configure S3 event notifications.

Question 14

A company runs a critical e-commerce application on Amazon ECS with Fargate launch type, fronted by an Application Load Balancer. The application uses an Amazon ElastiCache for Redis cluster for session state and an Amazon RDS for MySQL Multi-AZ database for persistent data. Recently, during a deployment of a new service version, the application became unresponsive for 15 minutes. The SysOps administrator discovered that the deployment updated the task definition with a new environment variable that pointed to an incorrect ElastiCache endpoint. The ECS service was configured with a rolling update, minimum healthy percent of 50%, and maximum percent of 200%. After the deployment, all tasks failed health checks due to a connection timeout to the wrong Redis endpoint. What is the MOST effective way to prevent this issue in future deployments?

Accepted Answer

Implement a blue/green deployment strategy using AWS CodeDeploy and test the new task definition before shifting traffic.. Implementing a blue/green deployment with AWS CodeDeploy allows testing the new task definition in a separate target group before shifting traffic. If the new tasks fail health checks (e.g., due to incorrect ElastiCache endpoint), traffic remains on the blue environment, preventing application downtime. Option A is incorrect because a CloudWatch alarm only triggers an alert or rollback after the issue occurs; it does not prevent the deployment from impacting users. Option B is incorrect because updating one task at a time (canary) still exposes tasks to the wrong configuration, and since the minimum healthy percent is 50%, at least half the tasks would fail before detection. Option D is incorrect because the ECS deployment circuit breaker rolls back only after the deployment fails, but it does not prevent the initial impact during the rolling update.

Answer

Configure a CloudWatch alarm that triggers an automatic rollback if the error rate exceeds 10%.

Answer

Update the ECS service to use a canary deployment by updating one task at a time.

Answer

Enable ECS deployment circuit breaker and set the rollback configuration to automatically roll back failed deployments.

Question 15

A company runs a web application on EC2 instances in an Auto Scaling group across two Availability Zones. The application uses an Application Load Balancer. The SysOps administrator receives an alert that the application is returning 503 errors. The administrator checks the CloudWatch metrics and sees that the ALB's RequestCount is normal, but the HealthyHostCount is zero. The EC2 instances are in running state and pass the EC2 status checks. What is the MOST likely cause and what should the administrator do to resolve the issue?

Accepted Answer

The ALB health check configuration is incorrect; verify the health check path and port.. Both a misconfigured ALB health check and a security group that blocks traffic from the ALB would result in HealthyHostCount=0 and 503 errors. Since the instances are running and passing status checks, either could be the cause. The administrator needs additional information, such as the health check response code or security group rules, to identify the exact issue.

Answer

The instances are out of memory; increase the instance size.

Answer

The Auto Scaling group's scaling policy is not launching new instances; update the policy.