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

Question 1

A company runs a web application on EC2 instances in an Auto Scaling group. The application is behind an Application Load Balancer. The company wants to ensure that the application can handle a sudden spike in traffic without downtime. What should the SysOps administrator do?

Accepted Answer

Configure a target tracking scaling policy based on average CPU utilization.. Dynamic scaling policies adjust capacity based on demand. Option A is wrong because manual scaling is not automated. Option C is wrong because scheduled scaling is for predictable patterns. Option D is wrong because it reduces availability.

Answer

Use a scheduled scaling policy to add instances during business hours.

Answer

Reduce the number of Availability Zones to lower latency.

Answer

Manually increase the desired capacity of the Auto Scaling group when traffic increases.

Question 2

A company has a production RDS for MySQL database. The SysOps administrator receives an alert that the database instance is running out of storage. The company requires high availability and minimal downtime during any modifications. What should the administrator do?

Accepted Answer

Modify the RDS instance to increase the allocated storage. Since the instance is Multi-AZ, the modification will be applied with minimal downtime.. Modifying the allocated storage for a Multi-AZ RDS instance can be done with minimal downtime; the modification is applied during the next maintenance window or immediately with a brief failover. Option A is wrong because it does not address the storage issue permanently. Option C is wrong because it requires more effort and potential downtime. Option D is wrong because read replicas do not increase storage capacity of the primary.

Answer

Add a read replica and use it for read traffic to reduce load on the primary.

Answer

Create a CloudWatch alarm to notify when storage is low, then manually clean up old data.

Answer

Create a new RDS instance with larger storage and migrate the data using AWS Database Migration Service.

Question 3

A company runs a stateless web application on EC2 instances in an Auto Scaling group. The application is deployed across multiple Availability Zones. The SysOps administrator wants to ensure that the application remains available even if an entire Availability Zone fails. What is the MOST effective way to achieve this?

Accepted Answer

Configure the Auto Scaling group to launch instances in at least two Availability Zones.. Configuring the Auto Scaling group to use multiple Availability Zones ensures that instances are distributed, so failure of one AZ does not affect all instances. Option A is wrong because it does not provide redundancy. Option B is wrong because it does not automatically recover. Option D is wrong because a single AZ does not protect against AZ failure.

Answer

Create a CloudWatch alarm to reboot instances when they become unhealthy.

Answer

Use a single Availability Zone to reduce complexity.

Answer

Use a larger instance type to handle more traffic.

Question 4

A company runs a critical application on AWS Lambda functions. The functions are invoked by an API Gateway endpoint. The SysOps administrator needs to ensure that the application continues to work if an entire AWS Region becomes unavailable. What should the administrator do?

Accepted Answer

Deploy the same API Gateway and Lambda setup in a second Region and use Route 53 with failover routing.. Route 53 can route traffic to a second Region where the same infrastructure is deployed. Option A is wrong because Lambda functions are regional. Option B is wrong because API Gateway is also regional. Option D is wrong because Lambda@Edge is for edge locations, not regional failover.

Answer

Use AWS Global Accelerator to route traffic to the closest Region.

Answer

Configure Lambda functions with provisioned concurrency in multiple Regions.

Answer

Use Lambda@Edge to run the functions at edge locations.

Question 5

A company runs a web application on EC2 instances in an Auto Scaling group behind an ALB. The application uses an RDS MySQL database. The SysOps administrator needs to improve the reliability of the database layer. Which TWO actions should the administrator take? (Choose two.)

Accepted Answer

Enable Multi-AZ on the RDS instance.. Multi-AZ provides automatic failover, and automated backups enable point-in-time recovery. Read replicas improve read performance but not high availability. Manual snapshots are not sufficient for automatic recovery. Larger instance class improves performance, not reliability.

Answer

Take a manual snapshot every hour.

Answer

Create a read replica in a different Region.

Answer

Increase the DB instance class to the largest available.

Question 6

A company uses AWS CloudFormation to deploy infrastructure. The SysOps administrator needs to ensure that if a stack update fails, the stack is automatically rolled back to the last known good state. Which THREE steps should the administrator take? (Choose three.)

Accepted Answer

Configure the stack to use a service role with permissions to perform rollback actions.. CloudFormation stack policies protect critical resources from accidental updates. Rollback triggers monitor stack metrics and initiate rollback if a threshold is breached. IAM permissions are necessary to allow CloudFormation to perform rollback. Manual snapshots and SNS notifications do not automate rollback.

Answer

Create a manual snapshot of the database before each update.

Answer

Enable termination protection on the stack.

Question 7

A company runs a critical application on EC2 instances in an Auto Scaling group. The group uses a dynamic scaling policy based on CPU utilization. The SysOps administrator wants to ensure that the application remains available during a planned maintenance event that will take down one of the Availability Zones. Which TWO actions should the administrator take? (Choose two.)

Accepted Answer

Update the Auto Scaling group to remove the affected Availability Zone from the list of enabled AZs.. Updating the ASG to use only the remaining AZs and rebalancing ensures capacity is maintained. Increasing desired capacity preemptively provides a buffer. Terminating instances prematurely reduces capacity. Updating the AMI does not help with AZ maintenance.

Answer

Manually terminate all instances in the affected Availability Zone.

Answer

Create a new launch configuration with a different AMI.

Answer

Disable the dynamic scaling policy to prevent scaling.

Question 8

A company runs a web application on EC2 instances behind an Application Load Balancer. The application stores session data in a DynamoDB table. To improve reliability, the SysOps administrator needs to ensure that session data is preserved if an EC2 instance fails. Which action should the administrator take?

Accepted Answer

Use DynamoDB to store session data, making it accessible from any instance.. Option A is correct because storing session data externally (e.g., in DynamoDB) ensures it survives instance failure. Option B is incorrect because EBS volumes are tied to a single AZ; mounting the same volume to multiple instances is not supported. Option C is incorrect because ElastiCache sessions are ephemeral and lost on cache node failure. Option D is incorrect because ELB sticky sessions cause uneven load and do not preserve session data on instance failure.

Answer

Enable sticky sessions (session affinity) on the ALB.

Answer

Mount the same EBS volume to all EC2 instances to share session data.

Answer

Store session data in an ElastiCache Memcached cluster.

Question 9

A SysOps administrator is configuring an Amazon RDS for MySQL Multi-AZ deployment. What is the primary benefit of using Multi-AZ?

Accepted Answer

Automatic failover to a standby instance in a different Availability Zone.. Option B is correct: Multi-AZ provides automatic failover to a standby in a different AZ, improving availability. Option A is incorrect because Multi-AZ does not increase write performance; writes are synchronous to standby. Option C is incorrect because Multi-AZ does not create read replicas (that's a separate feature). Option D is incorrect because Multi-AZ does not provide cross-Region replication without additional configuration.

Answer

Improved read performance by distributing queries across multiple instances.

Answer

Synchronous replication across AWS Regions.

Answer

Automatic creation of read replicas for disaster recovery.

Question 10

A company has a critical application running on EC2 instances in an Auto Scaling group behind an ALB. The application uses a custom health check endpoint at /health. The SysOps administrator notices that the ALB occasionally marks instances as unhealthy even though the application is running correctly. The health check settings are: HealthCheckIntervalSeconds=30, HealthyThresholdCount=5, UnhealthyThresholdCount=2. What is the most likely cause of the intermittent health check failures?

Accepted Answer

The HealthyThresholdCount is set too high, causing instances to remain unhealthy after transient issues.. Option C is correct: With HealthyThresholdCount=5, an instance must pass 5 consecutive health checks to be marked healthy. If the health check endpoint returns a single 5xx error due to a transient issue, the instance may be considered unhealthy for a prolonged period. Option A is incorrect because TCP health checks are less granular but would not cause intermittent failures if the instance is reachable. Option B is incorrect because an UnhealthyThresholdCount of 2 is standard and not too low. Option D is incorrect because 5xx errors are not ignored by ALB health checks.

Answer

The health check endpoint returns 5xx errors, which are ignored by the ALB.

Answer

The UnhealthyThresholdCount is set too low.

Answer

The health check is using TCP instead of HTTP.

Question 11

A company uses Amazon S3 to store critical data. The SysOps administrator needs to protect against accidental deletion of objects. Which combination of actions should the administrator take? (Choose the best answer.)

Accepted Answer

Enable S3 Versioning and MFA Delete on the bucket.. Option B is correct: Enable S3 Versioning to preserve deleted objects and MFA Delete to require additional authentication for permanent deletions. Option A is incorrect because bucket policies do not prevent deletion by authorized users. Option C is incorrect because replication does not protect against deletion; it copies objects to another bucket. Option D is incorrect because lifecycle policies can delete objects automatically, increasing risk.

Answer

Apply a bucket policy that denies s3:DeleteObject for all principals.

Answer

Set a lifecycle policy to expire objects after 30 days.

Answer

Configure cross-Region replication to a different bucket.

Question 12

A SysOps administrator is designing a disaster recovery plan for a web application that runs on EC2 instances with data stored in an RDS MySQL database. The application requires a Recovery Point Objective (RPO) of 5 minutes and a Recovery Time Objective (RTO) of 1 hour. Which solution meets these requirements most cost-effectively?

Accepted Answer

Use RDS Multi-AZ with automated backups and EC2 AMI backups.. Option C is correct: RDS Multi-AZ with automatic backups provides synchronous standby replication and point-in-time recovery, meeting RPO of 5 minutes. AMI backups of EC2 can be used to launch instances quickly, meeting RTO of 1 hour. Option A is incorrect because read replicas are not used for failover by default; promoting a read replica takes time. Option B is incorrect because standby EC2 in another Region incurs higher costs and complexity. Option D is incorrect because a single RDS instance is a single point of failure.

Answer

Use a single RDS instance with daily snapshots and EC2 instance store.

Answer

Use EC2 Auto Scaling across Regions with an RDS standby instance.

Answer

Use RDS Multi-AZ with read replicas in another Region.

Question 13

A company runs a stateful application on EC2 instances in an Auto Scaling group. The application maintains state in memory. The SysOps administrator wants to ensure that when an instance is terminated, the state is preserved and a new instance can resume operation. Which approach should the administrator use?

Accepted Answer

Use an Auto Scaling lifecycle hook to offload state before termination.. Option B is correct: A lifecycle hook can intercept the termination event and run a script to offload state to S3 or another durable store. Option A is incorrect because ELB connection draining only stops new connections; it does not preserve state. Option C is incorrect because graceful shutdown scripts can run on termination, but they may not complete if the instance is terminated quickly. Option D is incorrect because a warm standby is costly and not designed for state offloading.

Answer

Use a warm standby instance that takes over when the primary fails.

Answer

Configure the EC2 instance to run a script on shutdown to save state locally.

Answer

Enable connection draining on the ALB.

Question 14

A SysOps administrator is tuning the health check of an Auto Scaling group. The group uses an ALB. The application takes up to 2 minutes to start. The health check settings are: HealthCheckGracePeriod=300, HealthCheckType=EC2. The administrator notices that instances are often marked unhealthy and terminated shortly after launch. What should the administrator change?

Accepted Answer

Change the HealthCheckType to EC2 (already EC2, but change to ELB).. Option C is correct: The HealthCheckGracePeriod is 300 seconds (5 minutes), which is sufficient for the 2-minute startup. However, HealthCheckType=EC2 means the ASG uses EC2 status checks, not ALB health checks. The EC2 status checks may fail if the instance is not fully initialized. Changing to ELB health checks allows the ASG to use the ALB health check, which can be configured to wait for the application to respond. Option A is incorrect because the grace period is already long enough. Option B is incorrect because increasing the grace period doesn't fix the health check type mismatch. Option D is incorrect because decreasing the grace period would make the problem worse.

Answer

Increase the HealthCheckGracePeriod to 600 seconds.

Answer

Change the HealthCheckType to ELB.

Answer

Decrease the HealthCheckGracePeriod to 120 seconds.

Question 15

A company wants to ensure that its Amazon RDS database can withstand the loss of an entire Availability Zone. Which feature should the SysOps administrator enable?

Accepted Answer

Enable Multi-AZ deployment.. Option B is correct: Multi-AZ deployment creates a standby in a different AZ; if the primary AZ fails, RDS automatically fails over to the standby. Option A is incorrect because read replicas can be in a different AZ but are not used for automatic failover. Option C is incorrect because manual snapshots require manual restoration. Option D is incorrect because automated backups are stored in S3 and do not provide automatic failover.

Answer

Enable automated backups with a retention period of 35 days.

Answer

Take manual snapshots and copy them to another Region.

Answer

Create a read replica in a different Availability Zone.