SOA-C02 Reliability and Business Continuity — 40 Questions

Question 1

An application uses an Amazon DynamoDB table with on-demand capacity. The SysOps administrator needs to ensure the table remains available during an AWS regional outage. Which strategy should be used?

Accepted Answer

Use DynamoDB global tables.. DynamoDB global tables provide multi-region, multi-active replication, ensuring the table remains available during an AWS regional outage by automatically replicating data across selected AWS Regions. This is the only option that addresses regional fault tolerance by design, as it uses DynamoDB's built-in replication to maintain availability and data durability across regions.

Answer

Enable DynamoDB Accelerator (DAX).

Answer

Create a read replica in another region.

Answer

Increase read and write capacity units.

Question 2

A SysOps administrator is testing the failover of an Amazon RDS for PostgreSQL Multi-AZ DB instance. The application currently writes to the primary instance in us-east-1a. Which action will manually trigger a failover to the standby instance in us-east-1b?

Accepted Answer

Reboot the DB instance and select 'Reboot with failover'.. Option A is correct because the 'Reboot with failover' option in the Amazon RDS console explicitly triggers a failover by rebooting the primary DB instance and forcing the Multi-AZ configuration to promote the standby instance in us-east-1b to become the new primary. This is the designed method for manually testing or initiating a failover in a Multi-AZ deployment.

Answer

Modify the DB instance to Single-AZ and then back to Multi-AZ.

Answer

Reboot the DB instance without selecting any failover option.

Answer

Promote the standby instance using the Amazon RDS console.

Question 3

A company runs a web application on Amazon EC2 instances in a single Availability Zone. The SysOps administrator wants to increase the availability of the application so that it can survive an Availability Zone failure. Which action is the most effective?

Accepted Answer

Launch EC2 instances in two different Availability Zones and place them behind an Application Load Balancer.. Option B is correct because deploying EC2 instances across two different Availability Zones and placing them behind an Application Load Balancer (ALB) provides fault isolation. If one AZ fails, the ALB automatically routes traffic to the healthy instances in the other AZ, ensuring the application remains available. This architecture directly addresses the goal of surviving an AZ failure by eliminating the single point of failure at the AZ level.

Answer

Deploy an additional EC2 instance in the same Availability Zone.

Answer

Enable termination protection on all EC2 instances.

Answer

Use an Amazon RDS Multi-AZ deployment for the database tier.

Question 4

A company runs a stateful web application on a single Amazon EC2 instance with an Elastic IP address. The SysOps administrator needs to increase availability so that if the instance fails, a new instance can be launched quickly with the same configuration and the same IP address. The administrator also needs to ensure data is not lost. Which solution meets these requirements with the least operational overhead?

Accepted Answer

Create an AMI from the instance, store data on an Amazon EFS file system, and use an Auto Scaling group with a lifecycle hook to associate the Elastic IP. Option B is correct because it separates the stateful data (stored on Amazon EFS) from the compute instance, ensuring data persistence even if the instance fails. Creating an AMI from the instance captures the configuration, and an Auto Scaling group with a lifecycle hook can associate the Elastic IP to the new instance automatically, providing a quick failover with minimal operational overhead.

Answer

Use an Application Load Balancer with an Auto Scaling group and a launch configuration that includes the Elastic IP

Answer

Create a CloudFormation template that launches a new instance and associates the Elastic IP

Answer

Place the instance in an Auto Scaling group with a minimum of 1 and a maximum of 1, and set the health check to replace unhealthy instances

Question 5

A company runs a critical production database on Amazon RDS for MySQL with a Multi-AZ deployment. The database experiences a primary instance failure. The SysOps administrator needs to understand exactly how the failover process worked and why the application experienced a longer-than-expected downtime. Which AWS service or feature should the administrator use to review detailed events and actions during the failover?

Accepted Answer

AWS Personal Health Dashboard. AWS Personal Health Dashboard provides a personalized view of the health of AWS services and resources, including detailed event logs for RDS Multi-AZ failovers. It surfaces the exact sequence of actions (e.g., DNS record update, failover initiation, completion) and any underlying AWS infrastructure issues that caused the extended downtime, such as degraded hardware or network latency. This is the correct tool because it gives the administrator a chronological, AWS-side account of the failover process, which is not available through other services.

Answer

Amazon RDS Performance Insights

Answer

Amazon CloudWatch Logs

Answer

AWS CloudTrail

Question 6

A company runs a stateless web application on Amazon EC2 instances in an Auto Scaling group with a minimum of 2 and maximum of 10 instances. The instances are behind an Application Load Balancer (ALB). The SysOps administrator needs to ensure that the application can survive the failure of an entire AWS Availability Zone (AZ) in the region. Which configuration is necessary?

Accepted Answer

Configure the Auto Scaling group with subnets in at least two Availability Zones and ensure the ALB has subnets in the same AZs.. Option A is correct because deploying the Auto Scaling group across multiple Availability Zones (AZs) and ensuring the ALB has subnets in the same AZs allows the application to continue serving traffic even if one entire AZ fails. The ALB can route requests to healthy instances in the remaining AZs, and the Auto Scaling group will replace failed instances in other AZs as needed, maintaining the minimum instance count. This architecture is a fundamental pattern for high availability in AWS.

Answer

Increase the Auto Scaling group minimum to 10 instances to absorb the failure.

Answer

Use larger instance types to handle the load of a failed AZ.

Answer

Use multiple Application Load Balancers in different AZs.

Question 7

A company runs a critical stateful web application on Amazon EC2 instances in a single AWS region. The application stores user session data in an Amazon ElastiCache for Redis cluster. The SysOps administrator must design a disaster recovery (DR) strategy that can survive a complete regional outage with a Recovery Point Objective (RPO) of 15 minutes and a Recovery Time Objective (RTO) of 1 hour. The application must be able to redirect users to the DR region with minimal manual effort. Which combination of actions meets these requirements?

Accepted Answer

Create a read replica of the ElastiCache Redis cluster in the DR region using the native cross-region replication feature. Use Route 53 with failover routing to point to the DR region ALB when the primary health check fails. Pre-configure EC2 instances in an Auto Scaling group in the DR region.. Option B is correct because ElastiCache for Redis supports cross-region replication via a read replica in the DR region, which can keep session data synchronized with minimal lag, meeting the 15-minute RPO. Route 53 failover routing with health checks on the primary region's ALB automatically redirects traffic to the pre-configured DR region EC2 instances and ALB, achieving the 1-hour RTO with minimal manual effort. Pre-configuring the DR region with an Auto Scaling group ensures compute capacity is ready, while the read replica provides the required data availability.

Answer

Use Amazon Route 53 with weighted routing to distribute traffic between the two regions. Use a global DynamoDB table for session data, and launch EC2 instances in the DR region only when a failure is detected using AWS CloudFormation StackSets.

Answer

Use an Amazon CloudFront distribution with multiple origins (primary and DR). Enable session stickiness at the CloudFront level. Use EC2 instances in both regions behind separate ALBs. No special data replication is needed because sessions are stored in Redis.

Answer

Use EC2 instances with an Auto Scaling group in both regions. Schedule a Lambda function to take snapshots of the Redis cluster every 15 minutes and copy them to the DR region. Use Route 53 latency routing to direct users to the nearest region.

Question 8

A company runs a critical production database on Amazon RDS for MySQL with Multi-AZ deployment. The SysOps administrator needs to be automatically notified when a failover event occurs, and also capture the exact time and reason for the failover for compliance purposes. Which AWS service or feature should be used to capture the failover event details with the least operational overhead?

Accepted Answer

Create an Amazon CloudWatch Events rule that matches the 'RDS DB Instance Event' for 'failover' and sends the event to an Amazon SNS topic for notification and logging.. Amazon CloudWatch Events (now part of Amazon EventBridge) can match RDS DB Instance events, including 'failover', and route them to an SNS topic for notification and to CloudWatch Logs for logging. This approach requires no custom scripting or polling, providing the least operational overhead while capturing the exact time and reason for the failover directly from the RDS event stream.

Answer

Enable detailed monitoring on the RDS instance and stream the logs to Amazon CloudWatch Logs where a metric filter can detect failover patterns.

Answer

Configure AWS CloudTrail to log all RDS API calls and analyze the logs for the 'Failover' event type.

Answer

Use AWS Config to create a config rule that evaluates whether the 'DBInstanceStatus' changes to 'failover' and then trigger a remediation action.

Question 9

A company runs a critical web application on Amazon EC2 instances that are part of an Auto Scaling group. The application receives unpredictable traffic spikes. The SysOps administrator needs to ensure that when a scale-out event occurs, new instances are ready to serve traffic quickly to minimize latency spikes. Currently, the instance launch and configuration process (including software installs and cache warming) takes about 5 minutes. The administrator wants to reduce the time it takes for new instances to start serving traffic. Which combination of Auto Scaling features should be used?

Accepted Answer

Implement an Auto Scaling warm pool with a minimum number of pre-initialized instances in a 'Stopped' state. Configure the scaling policy to move instances from the warm pool to the Auto Scaling group when needed.. Option B is correct because an Auto Scaling warm pool maintains a pool of pre-initialized instances in a 'Stopped' state that are fully configured (software installed, cache warmed) and ready to serve traffic. When a scale-out event occurs, instances from the warm pool are moved to the Auto Scaling group and transitioned to 'Running' state, bypassing the 5-minute launch and configuration delay, thereby minimizing latency spikes.

Answer

Use a launch template that includes a pre-warmed Amazon Machine Image (AMI) with all software pre-installed, and configure the Auto Scaling group to use a larger instance type to reduce initialization time.

Answer

Use scheduled scaling to predictively launch instances before the traffic spikes based on historical patterns.

Answer

Configure lifecycle hooks to add a wait time during instance launch so that the instance is fully configured before it is placed behind the load balancer.

Question 10

A company runs a stateful web application on a single Amazon EC2 instance. The SysOps administrator needs to implement a high availability architecture that can tolerate an Availability Zone (AZ) failure. The application stores session state in memory and also writes critical data to an Amazon EBS volume. The administrator wants to use an Auto Scaling group and an Application Load Balancer (ALB). Which combination of steps is required to make the application highly available?

Accepted Answer

Migrate session state to Amazon ElastiCache for Redis, store critical data in Amazon EFS, create an Auto Scaling group across multiple AZs, and place it behind an ALB.. Option B is correct because it addresses both the stateless requirement for horizontal scaling and the persistence of critical data across AZ failures. Migrating session state to ElastiCache for Redis removes the dependency on local instance memory, allowing any instance to handle any request. Storing critical data on Amazon EFS provides a shared, NFS-based file system that is accessible from all instances across multiple AZs, unlike EBS which is tied to a single AZ. Combining these with a multi-AZ Auto Scaling group and an ALB ensures the application can survive an entire AZ outage.

Answer

Create an Auto Scaling group that spans at least two Availability Zones, attach the existing EBS volume to the new instances, and use an ALB to distribute traffic.

Answer

Place the EC2 instance in an Auto Scaling group with a minimum and maximum of 1 in the same AZ, and attach an Elastic IP to the instance.

Answer

Use an ALB with the existing single instance as the target, and enable cross-zone load balancing.

Question 11

A company runs a critical web application on Amazon EC2 instances in an Auto Scaling group behind an Application Load Balancer (ALB). The application uses session stickiness (sticky sessions) to maintain user sessions. The SysOps administrator notices that when instances are replaced during a scale-in or failure event, users lose their session data. The administrator needs to preserve session data across instance failures without losing stickiness benefits. What should the administrator do?

Accepted Answer

Disable sticky sessions on the ALB and configure the application to store session data in an external session store like Amazon ElastiCache for Redis.. Option A is correct because storing session data externally in a service like Amazon ElastiCache for Redis decouples session state from the EC2 instance lifecycle. This allows the ALB to continue using sticky sessions to route a user to the same instance, but if that instance fails or is replaced, the new instance can retrieve the session data from the shared Redis cache, preserving the user's session without interruption.

Answer

Increase the stickiness duration to a very high value so that sessions are not lost during brief interruptions.

Answer

Change the Auto Scaling group to use a larger instance type to handle more sessions per instance, reducing the likelihood of session loss.

Answer

Configure the Auto Scaling group to use a larger minimum size and a lower maximum, so instances are less likely to be terminated.

Question 12

A company runs a critical web application on Amazon EC2 instances in an Auto Scaling group across three Availability Zones in us-east-1. The application stores data in an Amazon RDS for MySQL DB instance with Multi-AZ deployment. The SysOps administrator needs to design a disaster recovery strategy that can recover from a complete regional outage. The Recovery Time Objective (RTO) is 2 hours and the Recovery Point Objective (RPO) is 1 hour. Which solution should the administrator implement?

Accepted Answer

Configure cross-region automated backups for the RDS instance with a backup window. Deploy an identical infrastructure stack in a second region using AWS CloudFormation StackSets. Create an Amazon Route53 DNS failover record set with health checks to automatically fail over to the second region.. Option C is correct because it meets both the RTO of 2 hours and RPO of 1 hour. Cross-region automated backups for RDS provide an RPO of 1 hour or less by continuously backing up transaction logs to a secondary region. Deploying an identical infrastructure stack via CloudFormation StackSets ensures rapid provisioning in the secondary region, and Route53 DNS failover with health checks automates traffic redirection within the RTO window.

Answer

Create a read replica of the RDS instance in a second region. Configure an Amazon CloudFront distribution with the ALB as origin. Use Route53 failover routing policy to route traffic to the CloudFront distribution.

Answer

Take daily manual snapshots of the RDS instance and copy them to a second region. Store the AWS CloudFormation template for the infrastructure in an S3 bucket with cross-region replication. In the event of a disaster, manually deploy the stack and restore the snapshot.

Answer

Use AWS Database Migration Service (DMS) to continuously replicate data to a second region. Use an Application Load Balancer in the primary region and a Network Load Balancer in the secondary region. Create a Route53 weighted routing policy to distribute traffic.

Question 13

A company runs a critical application on Amazon EC2 instances with data stored on Amazon EBS volumes. The SysOps administrator needs to implement a backup strategy that supports point-in-time recovery with a Recovery Point Objective (RPO) of 1 hour and a Recovery Time Objective (RTO) of 4 hours. Which solution meets these requirements with the least operational overhead?

Accepted Answer

Use AWS Backup to schedule hourly EBS snapshots and restore to a new volume when needed.. AWS Backup provides a fully managed, policy-based backup service that can schedule EBS snapshots hourly, meeting the 1-hour RPO. Restoring from an AWS Backup snapshot to a new EBS volume and attaching it to an EC2 instance can be completed within the 4-hour RTO, with minimal operational overhead as it eliminates the need for custom scripts or lifecycle management.

Answer

Use Amazon Data Lifecycle Manager (DLM) to take hourly snapshots and create an AWS CloudFormation template to launch a new instance from the snapshot.

Answer

Use custom scripts to copy snapshots to an Amazon S3 bucket and restore from there.

Answer

Use Amazon S3 Lifecycle policies to transition data to Amazon S3 Glacier.

Question 14

A company runs a web application on Amazon EC2 instances in an Auto Scaling group behind an Application Load Balancer (ALB). The application stores session state in memory on each instance. The SysOps administrator wants to make the application highly available across multiple Availability Zones without losing session data when instances are terminated or replaced. The solution must minimize application changes. Which approach should the administrator take?

Accepted Answer

Store session data in a shared Amazon ElastiCache cluster and modify the application to read/write session state to ElastiCache.. Option B is correct because storing session state in a shared Amazon ElastiCache cluster decouples session data from individual EC2 instances, allowing any instance in the Auto Scaling group to serve any user request without losing session data when instances are terminated or replaced. This approach requires minimal application changes (only modifying the session handler to point to ElastiCache) and supports high availability across multiple Availability Zones by using a replicated ElastiCache cluster (e.g., Redis with replication).

Answer

Use sticky sessions (session affinity) on the ALB and configure the Auto Scaling group with a larger min size.

Answer

Deploy the application in multiple AWS Regions and use Amazon Route 53 with latency-based routing.

Answer

Store session data in an Amazon RDS for MySQL database and configure the application to read/write session state to the database.

Question 15

A company runs a critical database workload on an Amazon RDS for MySQL DB instance with Multi-AZ deployment in the us-east-1 region. The SysOps administrator must design a disaster recovery strategy that can recover from a complete regional outage. The Recovery Time Objective (RTO) is 2 hours and the Recovery Point Objective (RPO) is 1 hour. Which solution meets these requirements at the lowest cost?

Accepted Answer

Create a cross-Region read replica in another Region and promote it to a standalone DB instance during a disaster.. Option C is correct because a cross-Region read replica continuously replicates data from the primary RDS MySQL instance to another Region with minimal lag, typically achieving an RPO of seconds to minutes, well within the 1-hour requirement. Promoting the replica to a standalone instance during a disaster can be done in minutes, meeting the 2-hour RTO. This approach is the lowest cost among the viable options as it uses existing replication infrastructure without additional data transfer fees for snapshots or DMS replication instances.

Answer

Create manual snapshots of the DB instance every hour and copy them to another AWS Region.

Answer

Enable automated backups with a retention period of 35 days and restore to a different Region when needed.

Answer

Use AWS Database Migration Service (DMS) to continuously replicate data to a DB instance in another Region.

Question 16

A company runs a stateful web application on a single Amazon EC2 instance. The application stores session state in memory and writes critical data to an Amazon EBS volume. The SysOps administrator needs to implement a highly available architecture that can tolerate an Availability Zone (AZ) failure. The administrator plans to use an Auto Scaling group and an Application Load Balancer (ALB). Which combination of steps is required to make the application highly available while preserving session and data durability across AZ failures?

Accepted Answer

Use an Auto Scaling group across multiple AZs, migrate session storage to Amazon ElastiCache (multi-AZ), and migrate application data from EBS to Amazon EFS (file system mounted across AZs).. Option C is correct because it addresses both session state and data durability across AZ failures. Migrating session storage to ElastiCache (multi-AZ) ensures session data survives instance failure, and migrating application data from EBS to EFS provides a shared, multi-AZ file system that persists independently of any single EC2 instance. This combination allows the Auto Scaling group to launch new instances in any AZ and immediately access both session and application data.

Answer

Create an AMI of the current instance, configure an Auto Scaling group with a launch template that uses the AMI, and attach the existing EBS volume to new instances.

Answer

Create a multi-AZ Auto Scaling group and use sticky sessions (session affinity) on the ALB to tie users to specific instances.

Answer

Use an Auto Scaling group in a single AZ and use a Multi-AZ RDS instance for data storage.

Question 17

A company runs a global e-commerce application that uses Amazon DynamoDB as its primary database. The application requires single-digit millisecond read and write latency from any region and must continue to operate during a regional outage with minimal data loss. Which DynamoDB feature should the SysOps administrator enable to meet these requirements?

Accepted Answer

DynamoDB global tables. DynamoDB global tables provide multi-Region, multi-active replication, enabling single-digit millisecond reads and writes from any Region while offering automatic failover and recovery during a regional outage. This feature uses DynamoDB Streams to replicate data across Regions with eventual consistency, meeting the requirement for continued operation with minimal data loss.

Answer

DynamoDB Accelerator (DAX)

Answer

DynamoDB Point-in-Time Recovery (PITR)

Answer

DynamoDB Auto Scaling

Question 18

A company runs a web application on two EC2 instances in different Availability Zones, each with an Elastic IP address. The SysOps administrator needs to automatically route traffic to the healthy instance and fail over if one instance becomes unhealthy. The application must be accessible via a single DNS name. Which Route 53 routing policy should be used?

Accepted Answer

Failover routing policy. The failover routing policy in Amazon Route 53 is designed to route traffic from a primary resource to a secondary resource when the primary becomes unhealthy. In this scenario, the two EC2 instances in different Availability Zones act as primary and secondary endpoints, and Route 53 uses health checks to monitor the primary instance. If the health check fails, Route 53 automatically fails over to the secondary instance, ensuring the application remains accessible via a single DNS name.

Answer

Weighted routing policy

Answer

Geolocation routing policy

Answer

Simple routing policy

Question 19

A company runs an Amazon RDS for MySQL DB instance in us-east-1. The SysOps administrator needs to implement a disaster recovery solution that can recover from a regional outage with a Recovery Point Objective (RPO) of less than 1 second and a Recovery Time Objective (RTO) of less than 1 minute. Which solution should the administrator use?

Accepted Answer

Aurora Global Database. Aurora Global Database is the correct choice because it provides a fully managed cross-region replication solution with a typical RPO of less than 1 second and an RTO of less than 1 minute during a regional failover. It uses a primary cluster in one region and up to five secondary clusters in other regions, with asynchronous replication that is optimized for low latency, meeting the stringent RPO/RTO requirements.

Answer

Multi-AZ deployment

Answer

Cross-region read replica

Answer

Automated snapshot copy to another region

Question 20

A company has an Amazon RDS for PostgreSQL DB instance with Multi-AZ deployment in us-east-1. The SysOps administrator must design a disaster recovery strategy to recover from a regional outage. The Recovery Time Objective (RTO) is 1 hour and the Recovery Point Objective (RPO) is 5 minutes. Which solution meets these requirements at the lowest cost?

Accepted Answer

Create a Read Replica in a different region and promote it during a disaster.. A cross-region Read Replica meets the RPO of 5 minutes because replication is continuous (asynchronous) with minimal lag, and the RTO of 1 hour is achievable by promoting the replica during a disaster. This is the lowest-cost option because it uses a single standby instance in another region without the overhead of a full Multi-AZ deployment or frequent snapshot transfers.

Answer

Take daily snapshots and copy them to another region.

Answer

Use cross-region automated backups.

Answer

Deploy a second Multi-AZ DB instance in another region.