SOA-C02 Reliability and Business Continuity Practice Test 11 — 15 Questions

Question 1

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?

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

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.

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Latency routing policy

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Weighted routing policy

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Geolocation routing policy

Question 2

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.

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

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

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

Question 3

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.. State stored locally on an EC2 instance is ephemeral and lost if the instance fails or is terminated. The most reliable solution is to externalize state to a durable, shared data store such as ElastiCache (for session state) or RDS (for relational state). This decouples the application from the instance lifecycle and allows any instance in the Auto Scaling group to serve requests.

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

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Use instance store volumes for the state data.

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Use Amazon SQS to store the state data.

Question 4

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.

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

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Increase the EC2 instance size to handle the load.

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Enable termination protection on the EC2 instances.

Question 5

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.

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Use a single large EC2 instance to eliminate complexity.

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Use a single NAT gateway for outbound traffic.

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Store application data on a single EBS volume.

Question 6

A company wants to implement a disaster recovery solution for its on-premises database using AWS. The solution must have an RPO of less than 1 hour and an RTO of less than 4 hours. Which THREE steps should the SysOps administrator take? (Choose THREE.)

Accepted Answer

Set up a cross-Region read replica for the RDS instance.. A cross-Region read replica for an RDS instance provides asynchronous replication to a secondary Region. After promoting the replica, the RTO can be under 4 hours, and the RPO is typically less than 1 hour. Option B is correct by launching an EC2 instance with the same database software and configuring continuous replication (e.g., log shipping or mirroring) from the on-premises database. This allows failover to the EC2 instance within the RPO and RTO targets. Option C is correct as AWS DMS can perform ongoing replication from the on-premises database to an RDS instance, meeting the RPO requirement with minimal data loss. Together, these steps form a multi-layered DR strategy: DMS for continuous replication, EC2 as a standby, and a cross-Region replica for regional resilience.

Answer

Use AWS DataSync to sync the database files to Amazon S3.

Answer

Configure the RDS instance with Multi-AZ.

Question 7

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.

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Set up cross-Region replication.

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Enable S3 Transfer Acceleration.

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Configure S3 event notifications.

Question 8

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%.

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

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

Question 9

A company runs a critical web application on EC2 instances behind an Application Load Balancer in a single Availability Zone. To improve reliability, what is the MOST effective design change?

Accepted Answer

Launch EC2 instances across two or more Availability Zones.. The most effective design change to improve reliability is to launch EC2 instances across two or more Availability Zones. This eliminates the single point of failure at the Availability Zone level, ensuring that if one AZ experiences an outage, the Application Load Balancer can route traffic to healthy instances in another AZ. This directly addresses the core reliability principle of fault isolation and high availability.

Answer

Place the RDS database in a Multi-AZ deployment.

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Add a second Application Load Balancer in the same Availability Zone.

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Increase the EC2 instance size to handle more traffic.

Question 10

A company's S3 bucket contains critical data. The bucket policy accidentally allowed public write access, and a malicious actor uploaded several objects. The company needs to recover the bucket to a known good state as quickly as possible. What should the SysOps administrator do?

Accepted Answer

Use S3 Versioning to restore the bucket to a previous version.. Enabling S3 Versioning allows restoring a bucket to a previous state by deleting the current versions of objects, effectively rolling back to the last good version before the malicious uploads. Option A is incorrect because S3 Object Lock prevents deletion or overwrite for a specified retention period but does not provide version rollback. Option B is incorrect because MFA Delete requires additional authentication for delete operations but does not help restore previous versions. Option D is incorrect because S3 Cross-Region Replication replicates objects to another region but does not provide versioning or rollback capabilities.

Answer

Enable S3 Object Lock on the bucket to prevent further modifications.

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Enable MFA Delete on the bucket to secure delete operations.

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Configure S3 Cross-Region Replication to replicate data to another region.

Question 11

A SysOps administrator needs to ensure that an EC2 instance automatically recovers from an underlying hardware failure. Which action should be taken?

Accepted Answer

Create a CloudWatch alarm on the StatusCheckFailed metric and configure the recovery action.. A CloudWatch alarm on the StatusCheckFailed metric can be configured with the 'recover' action to automatically restart the EC2 instance on a new underlying host if a hardware failure is detected. This recovery action preserves the instance ID, private IP, Elastic IP, and instance metadata, ensuring minimal disruption. The StatusCheckFailed metric specifically monitors the instance's system status checks, which detect AWS hardware issues.

Answer

Launch a second instance in a different Availability Zone.

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Assign an Elastic IP address to the instance.

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Place the instance in an Auto Scaling group with a min size of 1.

Question 12

A company uses AWS Backup to back up its Amazon EFS file systems. The SysOps administrator needs to ensure that backups are retained for 7 years to meet compliance requirements. What should the administrator do?

Accepted Answer

Create a backup plan with a lifecycle policy that retains backups for 7 years.. AWS Backup allows you to define backup plans that include lifecycle policies to automatically transition backups to cold storage and expire them after a specified retention period. By setting the retention period to 7 years (2557 days) in the backup plan, AWS Backup will automatically manage the deletion of backups after that time, ensuring compliance without manual intervention.

Answer

Manually delete backups older than 7 years every month.

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Increase the backup frequency to daily.

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Configure cross-region backup to copy backups to another region.

Question 13

A SysOps administrator is designing a disaster recovery strategy for a production RDS MySQL database. The database must be recoverable within 15 minutes with a Recovery Point Objective (RPO) of less than 5 seconds. Which TWO actions should the administrator take? (Choose two.)

Accepted Answer

Enable Multi-AZ deployment for the RDS instance.. Multi-AZ deployment (Option B) provides automatic failover to a standby replica in a different Availability Zone, enabling recovery within minutes and meeting the 15-minute RTO. Cross-Region read replicas (Option C) allow asynchronous replication to another region with an RPO typically under 5 seconds, satisfying the RPO requirement. Together, they ensure both rapid failover and minimal data loss.

Answer

Create a read replica in the same AWS Region.

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Enable automated backups with a retention period of 35 days.

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Take manual snapshots every hour.

Question 14

A company runs a stateless web application on EC2 instances in an Auto Scaling group. To improve reliability during a traffic spike, which THREE actions should the SysOps administrator take? (Choose three.)

Accepted Answer

Configure a target tracking scaling policy based on average CPU utilization.. A target tracking scaling policy based on average CPU utilization allows the Auto Scaling group to automatically adjust the number of EC2 instances in response to traffic spikes. This policy maintains the target metric (e.g., 50% CPU) by adding or removing instances, ensuring the application remains responsive without manual intervention. It is a key mechanism for improving reliability under variable load.

Answer

Enable detailed monitoring for EC2 instances.

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Use a larger instance type to handle more traffic per instance.

Question 15

A company runs a web application on EC2 instances in an Auto Scaling group behind an Application Load Balancer. The application is deployed in a single Availability Zone. The SysOps administrator notices that during peak hours, the application becomes slow and some requests fail. CloudWatch metrics show that CPU utilization on the instances reaches 90%, but the Auto Scaling group does not scale out. The administrator has configured a target tracking scaling policy based on average CPU utilization with a target value of 75%. The Auto Scaling group has a minimum of 2, maximum of 10, and desired capacity of 2. What is the MOST likely reason the Auto Scaling group is not scaling out?

Accepted Answer

The Auto Scaling group is configured with a single Availability Zone, and the target tracking policy cannot scale out beyond the capacity of that single AZ.. The most likely reason is that the Auto Scaling group is configured with a single Availability Zone. Target tracking scaling policies operate within the constraints of the configured subnets. If the group is only in one AZ, the subnet may have insufficient IP addresses or the AZ may have reached its instance limit, preventing the group from scaling out beyond that AZ's capacity. Since the group has a maximum of 10, but the AZ capacity is limited, the scaling policy cannot add more instances. This is a common issue: AWS recommends using multiple Availability Zones for Auto Scaling groups to allow scaling across AZs and avoid single points of failure.

Answer

The target tracking policy uses a target value of 75%, but the average CPU is above that, so it should scale out.

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The target tracking policy requires detailed monitoring to be enabled on the instances.

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The Auto Scaling group has reached its maximum capacity of 10 instances.