SOA-C02 Reliability and Business Continuity Practice Test 14 — 15 Questions

Question 1

A company runs a web application on EC2 instances behind an Application Load Balancer. The instances are in an Auto Scaling group. The SysOps administrator wants to ensure that the application can handle a sudden increase in traffic without downtime. Which THREE actions should be taken?

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

Accepted Answer

Configure the Auto Scaling group to launch instances in multiple Availability Zones.. Launching instances in multiple Availability Zones (AZs) ensures high availability and fault tolerance. If one AZ experiences a failure, the Auto Scaling group can still serve traffic from instances in other AZs, preventing downtime during sudden traffic spikes or infrastructure issues.

Answer

Configure a scheduled scaling policy to add instances during known peak hours.

Answer

Use Spot Instances to reduce costs.

Question 2

A company has a production application running on Amazon ECS with Fargate. The application must be highly available across multiple Availability Zones. Which TWO configurations should be implemented?

Accepted Answer

Configure the ECS service to run tasks in at least two Availability Zones.. Running ECS tasks across at least two Availability Zones ensures that if one AZ fails, the service continues to operate in the other AZ, meeting the high-availability requirement. Option D is correct because placing the ECS service behind an Application Load Balancer (ALB) enables health checks and automatic traffic distribution to healthy tasks, which is essential for maintaining availability during task failures or AZ disruptions.

Answer

Configure the ECS service to run tasks in a single Availability Zone to reduce network latency.

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Use the awsvpc network mode for the task definition.

Answer

Use Fargate Spot capacity providers to reduce costs.

Question 3

A company is running a web application on EC2 instances in an Auto Scaling group behind an Application Load Balancer. The application stores session data on the local instance storage. Users are experiencing session loss during scaling events. What should a SysOps administrator do to maintain session persistence?

Accepted Answer

Move session data to an ElastiCache for Redis cluster.. Session data stored on local instance storage is ephemeral and lost when instances are terminated or replaced during scaling events. Moving session data to ElastiCache for Redis provides a centralized, durable, and low-latency session store that persists independently of EC2 instance lifecycles, ensuring session continuity across scaling operations.

Answer

Increase the EC2 instance size to reduce the frequency of scaling events.

Answer

Attach an Amazon EBS volume to each instance and store session data there.

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Enable sticky sessions on the Application Load Balancer.

Question 4

A company has a production DynamoDB table with on-demand capacity. They need to ensure business continuity with a Recovery Point Objective (RPO) of 5 minutes and a Recovery Time Objective (RTO) of 1 hour in case of a regional outage. What is the MOST cost-effective solution?

Accepted Answer

Enable DynamoDB global tables for the table.. DynamoDB global tables provide multi-region, multi-active replication with changes typically propagated within seconds, meeting an RPO of 5 minutes and an RTO of 1 hour by allowing traffic to be redirected to a replica in another region. This is the most cost-effective solution because it eliminates the need for separate backup storage or compute resources, and on-demand capacity scales automatically without provisioning.

Answer

Use AWS Backup to schedule daily backups and restore in another region.

Answer

Enable point-in-time recovery (PITR) on the table.

Answer

Configure cross-region read replicas for the table.

Question 5

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

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 an EC2 recovery action. When the alarm triggers (e.g., due to an underlying hardware failure), the recovery action automatically stops and starts the instance on healthy hardware, preserving the instance ID, private IP, Elastic IP, and EBS attachments. This is the native AWS mechanism for automatic instance recovery from hardware failures.

Answer

Use AWS Lambda to periodically check instance health and reboot if necessary.

Answer

Enable termination protection on the instance.

Answer

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

Question 6

A company uses an RDS for MySQL Multi-AZ DB instance. They want to minimize downtime during a planned maintenance update that requires a database engine version upgrade. What should the SysOps administrator do?

Accepted Answer

Use the AWS Console to apply the maintenance update immediately; the Multi-AZ configuration will minimize downtime.. RDS for MySQL Multi-AZ deployments perform engine version upgrades with automatic failover, which minimizes downtime by updating the standby instance first, then promoting it to primary. The Multi-AZ configuration ensures that the upgrade process is applied with reduced impact, typically causing only a brief interruption during the failover rather than a full outage.

Answer

Modify the DB instance to be a Single-AZ deployment, then apply the upgrade.

Answer

Take a snapshot, restore it as a new instance, and upgrade that instance.

Answer

Create a read replica in the same region, upgrade the replica, and promote it.

Question 7

A SysOps administrator is designing a disaster recovery plan for a web application. The application runs on EC2 instances in a single Availability Zone. What is the FIRST step to improve availability?

Accepted Answer

Deploy EC2 instances in at least two Availability Zones.. The application currently runs on EC2 instances in a single Availability Zone, which creates a single point of failure. The first step to improve availability is to eliminate this zone-level failure by deploying EC2 instances in at least two Availability Zones, as this provides fault isolation against an AZ outage. This foundational change directly addresses the root cause of the availability risk before adding other components like load balancers or database replication.

Answer

Use an Application Load Balancer to distribute traffic.

Answer

Enable Multi-AZ for the RDS database.

Answer

Create an Amazon CloudFront distribution for the application.

Question 8

A company has a production RDS for PostgreSQL instance. They need to recover from a logical corruption that occurred 2 hours ago. Which recovery method will minimize data loss?

Accepted Answer

Perform a point-in-time recovery to a time just before the corruption occurred.. Point-in-time recovery (PITR) for RDS PostgreSQL allows you to restore the database to any second within the backup retention period, using automated backups and transaction logs. By restoring to a time just before the logical corruption occurred (2 hours ago), you can recover the database to its state before the corruption, minimizing data loss to only transactions that happened after that point. This is the only option that can target a specific moment before the corruption, unlike a snapshot which is a fixed point in time.

Answer

Restore from the latest automated snapshot taken 1 hour ago.

Answer

Use pg_dump to export the database and restore it.

Answer

Fail over to the read replica in another AZ.

Question 9

An application uploads files to an S3 bucket. The SysOps administrator needs to ensure that the files are automatically replicated to another bucket in a different AWS Region for disaster recovery. Which action should be taken?

Accepted Answer

Enable Cross-Region Replication on the source bucket.. Cross-Region Replication (CRR) is the correct AWS feature to automatically replicate objects from a source S3 bucket to a destination bucket in a different AWS Region. CRR requires versioning to be enabled on both the source and destination buckets, and it copies every object uploaded to the source bucket asynchronously to the destination bucket, providing disaster recovery across regions.

Answer

Use S3 Transfer Acceleration for faster uploads.

Answer

Enable versioning on the source bucket.

Answer

Configure a lifecycle policy to transition objects to Glacier.

Question 10

Which TWO actions improve the availability of an application running on EC2 instances in a single Auto Scaling group? (Choose 2)

Accepted Answer

Use an Elastic Load Balancer with health checks to route traffic only to healthy instances.. An Elastic Load Balancer (ELB) performs health checks against EC2 instances and automatically routes traffic only to instances that pass those checks. If an instance becomes unhealthy, the ELB stops sending traffic to it, preventing user requests from reaching a failing instance and thereby improving application availability.

Answer

Increase the instance size to handle higher load.

Answer

Create a CloudWatch alarm to notify when the CPU utilization exceeds 80%.

Answer

Enable EBS optimization on the instances.

Question 11

Which THREE measures help protect an S3 bucket from accidental data loss? (Choose 3)

Accepted Answer

Enable MFA Delete on the bucket.. Enabling MFA Delete on an S3 bucket requires multi-factor authentication for any delete operations, adding an extra layer of protection against accidental or unauthorized deletion of objects. This helps prevent data loss by ensuring that even if credentials are compromised, a delete action cannot be performed without the MFA token.

Answer

Create a lifecycle policy to transition objects to S3 Glacier.

Answer

Enable server-side encryption on the bucket.

Question 12

A SysOps administrator runs the above command for an EC2 instance. The instance is running but the system status check is impaired. What does this indicate?

Accepted Answer

There is a problem with the underlying physical host that requires stopping and starting the instance.. The system status check in AWS EC2 monitors the underlying physical host for issues such as loss of network connectivity, power loss, or hardware failure. When this check is impaired, it indicates a problem with the host that requires stopping and starting the instance to migrate it to a new healthy host. Option C is correct because stopping and starting the instance forces a migration to a different physical host, resolving the underlying hardware issue.

Answer

The instance is still running but the application is not responding.

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The instance is unreachable due to a misconfigured security group.

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The operating system on the instance has crashed.

Question 13

A SysOps administrator creates the above IAM policy for a user. The user reports that they cannot delete an object in the bucket 'my-bucket' even though they are using MFA. What is the likely cause?

Accepted Answer

The user is not using MFA when making the API call.. The policy requires MFA for all s3:DeleteObject actions, as indicated by the condition key aws:MultiFactorAuthPresent set to 'true'. If the user reports they cannot delete an object despite using MFA, the most likely cause is that they are not actually using MFA when making the API call — for example, they may have authenticated with long-term credentials (access key/secret key) without a multi-factor authentication session. The condition key checks the presence of an MFA-authenticated session token, not just whether the user has MFA enabled on their account.

Answer

The resource ARN is missing the bucket-level permission.

Answer

The condition key aws:MultiFactorAuthPresent is incorrectly spelled.

Answer

The policy does not include s3:DeleteObjectVersion.

Question 14

A SysOps administrator deploys the above CloudFormation template. The stack creation fails with an error. What is the most likely reason?

Accepted Answer

The VolumeAttachment resource is missing the Device property.. The VolumeAttachment resource in AWS CloudFormation requires the Device property to specify the device name (e.g., /dev/sdf) for the attached EBS volume. Without this property, CloudFormation cannot determine the mount point, causing the stack creation to fail. The error occurs because the template omits this required field.

Answer

The EBS volume must specify a SnapshotId.

Answer

The template uses a deprecated AWSTemplateFormatVersion.

Answer

The instance and volume are in different Availability Zones.

Question 15

A company is designing a highly available web application on AWS. The application runs on EC2 instances behind an Application Load Balancer. Which configuration ensures that the application remains available if an entire AWS Availability Zone fails?

Accepted Answer

Launch EC2 instances in at least two different Availability Zones.. Deploying EC2 instances in at least two different Availability Zones (AZs) ensures that if one AZ fails, the Application Load Balancer (ALB) can route traffic to healthy instances in the remaining AZ(s). ALBs are regional constructs that automatically distribute traffic across registered targets in multiple AZs, and they perform health checks to detect and route away from failed AZs. This design meets the high availability requirement by eliminating the AZ as a single point of failure.

Answer

Deploy EC2 instances in multiple subnets of the same Availability Zone.

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Use a larger EC2 instance type to handle the load.

Answer

Use EC2 instances in multiple AWS Regions.