SOA-C02 Reliability and Business Continuity Practice Test 3 — 15 Questions

Question 1

Match each AWS storage service to its description.

Accepted Answer

Amazon S3: Object storage for internet-scale data.. Amazon S3 is object storage, EBS is block storage, EFS is file storage, and Glacier is archival. Common confusions include mixing S3 and EBS definitions.

Answer

Amazon S3: Block-level storage for EC2 instances.

Answer

Amazon EBS: Object storage for internet-scale data.

Question 2

Match each AWS backup and disaster recovery service to its feature.

Accepted Answer

AWS Backup: Centralized backup service that automates and consolidates backup tasks across AWS services.. The correct matches are: AWS Backup for centralized automation, AWS Elastic Disaster Recovery for continuous replication, AWS Storage Gateway for hybrid cloud storage, and AWS Snowball for offline transfer. Common confusions involve swapping the centralized backup and replication functions.

Answer

AWS Backup: Continuous block-level replication for fast recovery of applications.

Answer

AWS Elastic Disaster Recovery: Centralized backup service that automates and consolidates backup tasks across AWS services.

Question 3

A company is running a critical web application on EC2 instances behind an Application Load Balancer. The instances are in an Auto Scaling group across two Availability Zones. The company needs to ensure that if an entire Availability Zone fails, the application remains available. Which configuration meets this requirement?

Accepted Answer

Configure the Auto Scaling group to launch instances in at least two Availability Zones.. Configuring the Auto Scaling group to launch instances in at least two Availability Zones ensures that if one AZ fails, the remaining AZ(s) continue to serve traffic. The Application Load Balancer automatically distributes incoming requests across healthy instances in all configured AZs, and the Auto Scaling group replaces failed instances in the remaining AZs, maintaining capacity. This design provides high availability without relying on a single AZ, which would be a single point of failure.

Answer

Use larger EC2 instance types to handle the load during a failure.

Answer

Use Amazon CloudFront to distribute traffic across multiple regions.

Answer

Launch all instances in the same Availability Zone to reduce latency.

Question 4

A company uses a Multi-AZ RDS for MySQL instance for its production database. During a maintenance window, the primary instance fails and a failover occurs. However, the application experiences a 5-minute downtime. The application uses a DNS CNAME record pointing to the RDS endpoint. What is the MOST likely cause of the downtime?

Accepted Answer

The application was using a cached DNS resolution for the RDS endpoint.. During a Multi-AZ RDS failover, the RDS DNS CNAME record is updated to point to the new primary instance in a different Availability Zone. However, the application's DNS resolver may have cached the previous IP address (TTL-based). If the application does not flush its DNS cache or the TTL is long, it continues to connect to the old (failed) IP, causing connection timeouts until the cache expires. This is the most likely cause of the 5-minute downtime, as RDS failovers typically complete within 1-2 minutes.

Answer

The application was not configured to retry connections after a failover.

Answer

The RDS endpoint changed after failover and the application did not update.

Answer

The failover process took longer than expected due to a large transaction log.

Question 5

A company wants to back up its on-premises file server to AWS. The backup must be encrypted in transit and at rest. Which AWS service should the company use to meet these requirements?

Accepted Answer

AWS Storage Gateway (File Gateway) backed by Amazon S3.. AWS Storage Gateway File Gateway provides a native NFS/SMB interface that allows on-premises file servers to back up data directly to Amazon S3. It encrypts data in transit using TLS (HTTPS) and at rest using S3 server-side encryption (SSE-S3 or SSE-KMS), meeting both requirements without custom scripting or additional infrastructure.

Answer

Amazon EBS volumes attached to an EC2 instance acting as a file server.

Answer

AWS CloudFormation to replicate the file server configuration.

Answer

Amazon S3 with server-side encryption and a custom script to upload files.

Question 6

A company has an AWS Lambda function that processes S3 events. The function is critical and must be available even if one Availability Zone fails. How can a SysOps administrator ensure high availability for the Lambda function?

Accepted Answer

No action is required; Lambda functions are inherently highly available within a region.. AWS Lambda functions are inherently highly available within an AWS Region. The Lambda service automatically runs your function across multiple Availability Zones (AZs) to handle failures of individual AZs. No additional configuration is required to achieve AZ-level resilience; the service manages the underlying compute fleet and network infrastructure to ensure continued operation even if one AZ fails.

Answer

Use an Application Load Balancer to distribute events to multiple Lambda functions.

Answer

Configure the Lambda function to run in two subnets in different Availability Zones.

Answer

Deploy the Lambda function in two separate regions and use Route 53 failover.

Question 7

A company runs a stateful web application on EC2 instances in an Auto Scaling group. The application uses a sticky session (session affinity) feature of the Application Load Balancer. During a scale-in event, some users lose their session data. What should the SysOps administrator do to prevent session data loss?

Accepted Answer

Store session state in an external data store such as Amazon ElastiCache.. Sticky sessions (session affinity) tie a user's session to a specific EC2 instance. When a scale-in event terminates that instance, the session data stored locally on the instance is lost. Storing session state in an external data store like Amazon ElastiCache decouples session data from individual instances, allowing any healthy instance to serve the user's request without data loss, even after a scale-in event.

Answer

Disable sticky sessions and use a round-robin routing algorithm.

Answer

Use a lifecycle hook to back up session data before termination.

Answer

Increase the Auto Scaling group's cooldown period to delay termination.

Question 8

A company wants to create a disaster recovery (DR) strategy for its RDS for PostgreSQL database. The primary database is in us-east-1. The company needs a recovery point objective (RPO) of less than 5 minutes and a recovery time objective (RTO) of less than 1 hour. Which solution meets these requirements?

Accepted Answer

Create a cross-region Read Replica in us-west-2 and promote it during a disaster.. A cross-region Read Replica for Amazon RDS PostgreSQL maintains an asynchronous replication lag typically under 5 seconds, easily meeting the RPO of less than 5 minutes. During a disaster, promoting the Read Replica to a standalone instance can be completed in minutes, satisfying the RTO of less than 1 hour. This approach provides both low RPO and fast recovery without the complexity of additional services.

Answer

Enable Multi-AZ in us-east-1 and create a standby in a different Availability Zone.

Answer

Use AWS Database Migration Service (DMS) to continuously replicate to an EC2 instance.

Answer

Take daily automated snapshots and copy them to us-west-2.

Question 9

A company has an S3 bucket that stores critical data. The bucket has versioning enabled. A SysOps administrator accidentally deletes a version of an object. What is the quickest way to recover the deleted version?

Accepted Answer

Copy the deleted version from the bucket's version history.. S3 object versioning maintains a version history for each object, including deleted versions. When a version is deleted, it is not permanently removed; instead, a delete marker is created, and the deleted version remains in the version history. The quickest way to recover it is to copy the deleted version ID from the bucket's version history (e.g., using the AWS CLI `aws s3api copy-object` with the `--version-id` parameter) to restore the object without contacting support or enabling additional features.

Answer

Use the S3 bucket's 'Undelete' feature.

Answer

Enable MFA Delete and then restore the object.

Answer

Contact AWS Support to restore the object.

Question 10

A company runs a production application on EC2 instances in an Auto Scaling group. The application stores data on an EBS volume. The SysOps administrator wants to ensure that the data is durable and available even if an EC2 instance fails. Which approach should the administrator take?

Accepted Answer

Migrate the data to Amazon EFS and mount it to all instances.. Amazon EFS provides a fully managed, scalable, and shared file system that can be mounted concurrently to multiple EC2 instances across Availability Zones. By migrating the data to EFS and mounting it to all instances in the Auto Scaling group, the data remains durable and available even if an individual EC2 instance fails, because the file system persists independently of any single instance's lifecycle.

Answer

Use an instance store volume and replicate data across instances.

Answer

Use an EBS volume with snapshots taken every hour.

Answer

Move the data to an S3 bucket and access it via S3 API.

Question 11

A company wants to ensure that its EC2 instances receive patches automatically to maintain security compliance. Which AWS service can be used to automate patch management?

Accepted Answer

AWS Systems Manager. AWS Systems Manager Patch Manager automates the process of patching managed EC2 instances and on-premises servers. It uses patch baselines to define approved patches and can schedule patching across maintenance windows, ensuring security compliance without manual intervention.

Answer

Amazon CloudWatch

Answer

AWS Config

Answer

AWS CloudTrail

Question 12

A company is designing a disaster recovery plan for its critical applications. The plan must minimize data loss and recovery time. Which TWO measures should the SysOps administrator implement?

Accepted Answer

Perform regular backups to Amazon S3.. Regular backups to Amazon S3 are a foundational data protection measure because S3 provides 99.999999999% durability and supports lifecycle policies for cost-effective long-term retention. This directly addresses the requirement to minimize data loss by ensuring point-in-time recovery copies exist independently of the primary infrastructure.

Answer

Set a recovery time objective (RTO) of 24 hours.

Answer

Use manual procedures to restore from backups.

Answer

Run all workloads in a single AWS region.

Question 13

A SysOps administrator is troubleshooting a high error rate on an Application Load Balancer (ALB). The ALB is configured with two target groups: one for EC2 instances and one for Lambda functions. The administrator notices that the EC2 target group is unhealthy. Which THREE steps should the administrator take to resolve the issue?

Accepted Answer

Verify that the EC2 instances' security groups allow traffic from the ALB.. The ALB communicates with EC2 instances using the private IP addresses of the instances. If the EC2 instances' security groups do not explicitly allow inbound traffic from the ALB's security group (or the ALB's VPC CIDR), the health checks and actual traffic will be blocked, causing the target group to be marked unhealthy. This is a common misconfiguration when the ALB and instances are in the same VPC.

Answer

Review the ALB's DNS resolution for the target instances.

Answer

Increase the size of the Auto Scaling group to distribute load.

Question 14

A company runs a stateless web application on EC2 instances behind an Application Load Balancer. The company wants to improve the application's availability and fault tolerance. Which TWO actions should the SysOps administrator take?

Accepted Answer

Configure Auto Scaling to maintain a minimum number of instances.. Auto Scaling can maintain a minimum number of EC2 instances, ensuring that if an instance fails, a replacement is automatically launched to keep the application running. This directly improves availability by providing automatic recovery from instance failures without manual intervention.

Answer

Use Amazon CloudFront as an origin for the ALB.

Answer

Disable termination protection on EC2 instances.

Answer

Use larger EC2 instance types.

Question 15

Refer to the exhibit. A SysOps administrator creates an IAM policy to allow an EC2 instance to upload objects to an S3 bucket. However, the instance is unable to upload objects. What is the MOST likely reason?

Accepted Answer

The IAM role is not attached to the EC2 instance.. The IAM role must be attached to the EC2 instance as an instance profile for the instance to assume the role and obtain temporary credentials. Without this attachment, the instance has no valid AWS credentials to sign API requests, so the s3:PutObject action will fail regardless of the permissions defined in the role's policy.

Answer

The S3 bucket has server-side encryption enabled.

Answer

The policy does not include s3:GetObject permission.

Answer

The bucket policy denies all access.