SAA-C03 Design Resilient Architectures Practice Test 12 — 15 Questions

Question 1

A ticket booking system runs on EC2 instances behind an Application Load Balancer. The design must tolerate the failure of one Availability Zone. What should the Auto Scaling group configuration include?

Accepted Answer

Subnets in at least two Availability Zones with health checks enabled. Option A is correct because an Auto Scaling group configured with subnets in at least two Availability Zones and health checks enabled ensures that if one AZ fails, EC2 instances in the remaining AZs continue to serve traffic. The Application Load Balancer distributes requests across healthy instances in multiple AZs, and the Auto Scaling group replaces failed instances in the affected AZ, maintaining capacity. This design meets the requirement to tolerate the failure of one Availability Zone.

Answer

All instances in one larger subnet

Answer

A Network Load Balancer in one subnet

Answer

A single EC2 instance with detailed monitoring

Question 2

A regional web application for a inventory service must fail over automatically to a secondary Region if the primary endpoint becomes unhealthy. Which two services or features are required?

Accepted Answer

Route 53 failover routing with health checks. Route 53 failover routing with health checks is correct because it monitors the health of the primary endpoint via periodic HTTP/HTTPS or TCP checks. If the health check fails, Route 53 automatically updates DNS resolution to point to the secondary Region's endpoint, enabling failover at the DNS level without manual intervention.

Answer

S3 Transfer Acceleration

Answer

AWS Organizations service control policies

Question 3

A patient portal receives bursts of orders that sometimes overwhelm a downstream fulfilment service. The architecture must absorb spikes and retry processing without losing requests. Which service should be placed between the web tier and fulfilment workers?

Accepted Answer

Amazon SQS queue. Amazon SQS is the correct choice because it acts as a durable, highly available message buffer between the web tier and the fulfilment workers. It decouples the components, allowing the web tier to enqueue requests immediately without waiting for the downstream service, and the workers can poll and process messages at their own pace. SQS automatically retains messages for up to 14 days and supports retries via a dead-letter queue, ensuring no requests are lost even during spikes.

Answer

AWS WAF

Answer

Amazon CloudFront

Answer

Amazon Route 53 weighted routing

Question 4

A claims workflow uses Amazon SQS. Poison messages are repeatedly failing and blocking useful retries. What should the architect configure?

Accepted Answer

A dead-letter queue with an appropriate maxReceiveCount. Option C is correct because a dead-letter queue (DLQ) with an appropriate maxReceiveCount allows messages that repeatedly fail processing to be moved out of the source queue after a specified number of receive attempts. This prevents poison messages from blocking the queue and consuming retry capacity, enabling the workflow to continue processing valid messages without interruption.

Answer

A FIFO queue without a redrive policy

Answer

Short polling instead of long polling

Answer

A larger message retention period only

Question 5

A trading dashboard stores uploaded documents in S3. The business requires a copy in another AWS Region for disaster recovery. What should be configured?

Accepted Answer

S3 Cross-Region Replication with versioning enabled. S3 Cross-Region Replication (CRR) with versioning enabled automatically replicates objects to a destination bucket in a different AWS Region, providing a durable, low-latency disaster recovery copy. Versioning must be enabled on both source and destination buckets to track object changes and ensure consistency during replication. This meets the requirement for a cross-region copy without manual intervention.

Answer

An EBS snapshot schedule

Answer

S3 lifecycle transition to Glacier Flexible Retrieval

Answer

A CloudFront distribution

Question 6

A content publishing system uses Lambda functions that call an unreliable third-party API. Failed events must be retained for later investigation after retries are exhausted. What should be configured?

Accepted Answer

A Lambda dead-letter queue or failure destination. A Lambda dead-letter queue (DLQ) or failure destination captures events that have exhausted all retry attempts, preserving them in Amazon SQS or SNS for later investigation. This ensures failed invocations from the unreliable third-party API are not lost and can be analyzed or replayed, meeting the requirement for retention after retries are exhausted.

Answer

Lambda reserved concurrency set to zero

Answer

A larger deployment package

Answer

CloudFront error pages

Question 7

A warehouse integration service must use shared file storage across Linux EC2 instances in multiple Availability Zones. The storage must remain available during an AZ failure. Which service should be used?

Accepted Answer

Amazon EFS with mount targets in multiple Availability Zones. Amazon EFS provides a fully managed, scalable, and elastic NFS file system that can be mounted concurrently on multiple Linux EC2 instances across different Availability Zones. By configuring mount targets in each AZ, the file system remains accessible even if one AZ fails, because the other mount targets continue to serve traffic. This meets the requirement for shared, highly available file storage across AZs.

Answer

S3 mounted as a POSIX file system without a file gateway

Answer

Instance store volumes

Answer

An EBS volume attached to all instances

Question 8

A payments API requires point-in-time recovery and accidental-delete protection for a DynamoDB table. Which two settings should the architect enable?

Accepted Answer

Deletion protection or tightly controlled delete permissions. Deletion protection (Option A) prevents accidental table deletion by blocking DropTable API calls unless explicitly disabled, which is essential for protecting the payments table from human error or automated scripts. Point-in-time recovery (Option B) enables continuous backups with 35-day granularity, allowing restoration to any second within that window to recover from accidental writes or data corruption. Together, these settings satisfy both the point-in-time recovery and accidental-delete protection requirements for the DynamoDB table.

Answer

Global secondary indexes

Answer

DAX

Question 9

A ticket booking system uses Aurora MySQL. The company wants fast cross-Region disaster recovery with low RPO. Which architecture should be considered?

Accepted Answer

Aurora Global Database. Aurora Global Database is designed for cross-Region disaster recovery with a typical RPO of 1 second or less, using storage-based replication that does not impact database performance. This meets the requirement for fast failover and low data loss, unlike manual snapshot-based approaches which have higher RPO and slower recovery.

Answer

A single-AZ Aurora cluster

Answer

An ElastiCache Redis replica

Answer

Manual snapshots copied monthly

Question 10

A inventory service exposes a static website from S3 and CloudFront. Users should still receive cached pages if the S3 origin has a short outage. Which feature helps most?

Accepted Answer

CloudFront caching with appropriate TTLs. CloudFront caches responses from the S3 origin based on configured TTLs (Cache-Control or Expires headers). If the S3 origin experiences a short outage, CloudFront can still serve cached pages to users from its edge locations, maintaining availability. This is the most direct way to ensure users receive content during origin failures.

Answer

AWS Backup Vault Lock

Answer

IAM Access Analyzer

Answer

S3 Select

Question 11

A patient portal must process every event at least once, but duplicate processing is acceptable if the consumer handles idempotency. Which eventing approach is most suitable?

Accepted Answer

Use Amazon SQS standard queue and design consumers to be idempotent. Amazon SQS standard queues provide at-least-once delivery, meaning each message is delivered at least once but may occasionally be delivered more than once. This aligns with the requirement that every event must be processed at least once, and since duplicate processing is acceptable when consumers are idempotent, the standard queue is the most suitable choice. SQS handles the decoupling and durability of messages without requiring custom infrastructure.

Answer

Use an in-memory queue on one EC2 instance

Answer

Use UDP messages sent directly to workers

Answer

Use CloudFront signed URLs

Question 12

A claims workflow uses an RDS MySQL database and must remain available during an Availability Zone failure with minimal application changes. What should the architect enable?

Accepted Answer

Multi-AZ deployment for the RDS DB instance. Multi-AZ deployment for RDS MySQL automatically provisions and maintains a synchronous standby replica in a different Availability Zone. In the event of an AZ failure, Amazon RDS automatically fails over to the standby, providing high availability with minimal application changes (the application simply reconnects to the same endpoint). This meets the requirement for availability during an AZ outage without requiring code modifications.

Answer

S3 Cross-Region Replication

Answer

EBS snapshots every hour

Answer

Read replicas only

Question 13

A trading dashboard runs on EC2 instances behind an Application Load Balancer. The design must tolerate the failure of one Availability Zone. What should the Auto Scaling group configuration include?

Accepted Answer

Subnets in at least two Availability Zones with health checks enabled. Option B is correct because distributing EC2 instances across subnets in at least two Availability Zones ensures that if one AZ fails, the Auto Scaling group can maintain capacity using instances in the remaining AZ(s). Enabling health checks allows the group to detect and replace unhealthy instances, which is essential for fault tolerance. This configuration meets the requirement to tolerate the failure of one Availability Zone.

Answer

A single EC2 instance with detailed monitoring

Answer

All instances in one larger subnet

Answer

A Network Load Balancer in one subnet

Question 14

A regional web application for a content publishing system must fail over automatically to a secondary Region if the primary endpoint becomes unhealthy. Which two services or features are required?

Accepted Answer

Route 53 failover routing with health checks. Route 53 failover routing with health checks (B) is required because it continuously monitors the health of the primary endpoint and automatically reroutes traffic to a secondary Region when the primary becomes unhealthy. This is achieved by configuring a primary and secondary failover record set in Route 53, where the health check is associated with the primary record. When the health check fails, Route 53 returns the secondary record's IP address, enabling automatic failover at the DNS level.

Answer

AWS Organizations service control policies

Answer

S3 Transfer Acceleration

Question 15

A warehouse integration service receives bursts of orders that sometimes overwhelm a downstream fulfilment service. The architecture must absorb spikes and retry processing without losing requests. Which service should be placed between the web tier and fulfilment workers?

Accepted Answer

Amazon SQS queue. Amazon SQS is the correct choice because it acts as a durable, fully managed message queue that decouples the web tier from the fulfilment workers. It can absorb bursts of orders by storing messages durably, and workers can poll the queue at their own pace, with built-in retry logic via visibility timeouts and dead-letter queues to ensure no requests are lost.

Answer

AWS WAF

Answer

Amazon Route 53 weighted routing

Answer

Amazon CloudFront