SAA-C03 Design Resilient Architectures Practice Test 13 — 15 Questions

Question 1

A content publishing system 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? The architecture review board prefers a managed AWS-native control.

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

Accepted Answer

CloudFront caching with appropriate TTLs. CloudFront caching with appropriate TTLs ensures that even if the S3 origin becomes temporarily unavailable, CloudFront can serve cached content from its edge locations to users. By setting a minimum TTL (e.g., 0 seconds for dynamic content or longer for static assets), CloudFront will continue to serve stale responses from cache during an origin outage, maintaining availability. This is a managed AWS-native feature that requires no additional infrastructure and aligns with the architecture review board's preference.

Answer

IAM Access Analyzer

Answer

AWS Backup Vault Lock

Answer

S3 Select

Question 2

A warehouse integration service must process every event at least once, but duplicate processing is acceptable if the consumer handles idempotency. Which eventing approach is most suitable? The architecture review board prefers a managed AWS-native control.

Accepted Answer

Use Amazon SQS standard queue and design consumers to be idempotent. Amazon SQS standard queues provide at-least-once delivery, which guarantees that every message is processed at least once, meeting the requirement that every event must be processed. Duplicate processing is acceptable because the consumer can be designed to handle idempotency. This is a managed, AWS-native service that aligns with the architecture review board's preference.

Answer

Use CloudFront signed URLs

Answer

Use UDP messages sent directly to workers

Answer

Use an in-memory queue on one EC2 instance

Question 3

A payments API uses an RDS MySQL database and must remain available during an Availability Zone failure with minimal application changes. What should the architect enable? The team wants the control to be enforceable during normal operations.

Accepted Answer

Multi-AZ deployment for the RDS DB instance. Multi-AZ deployment for RDS MySQL automatically provisions and synchronously replicates a standby instance 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 only needs to reconnect using the same endpoint). This meets the requirement of remaining available during an AZ failure while being enforceable during normal operations.

Answer

S3 Cross-Region Replication

Answer

Read replicas only

Answer

EBS snapshots every hour

Question 4

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? The team wants the control to be enforceable during normal operations.

Accepted Answer

Subnets in at least two Availability Zones with health checks enabled. Distributing subnets across at least two Availability Zones ensures that if one AZ fails, the Auto Scaling group can launch replacement instances in the remaining AZ(s) to maintain capacity. Enabling health checks on the Application Load Balancer allows the Auto Scaling group to detect and replace unhealthy instances, enforcing resilience during normal operations without manual intervention.

Answer

All instances in one larger subnet

Answer

A Network Load Balancer in one subnet

Answer

A single EC2 instance with detailed monitoring

Question 5

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? The team wants the control to be enforceable during normal operations.

Accepted Answer

Amazon SQS queue. Amazon SQS is the correct choice because it acts as a durable buffer between the web tier and fulfilment workers, decoupling the producers from consumers. When bursts of orders arrive, SQS queues the messages and allows the fulfilment service to poll and process them at its own pace, absorbing spikes without data loss. The queue provides at-least-once delivery and supports retries via a dead-letter queue, ensuring no requests are lost even if processing fails.

Answer

AWS WAF

Answer

Amazon CloudFront

Answer

Amazon Route 53 weighted routing

Question 6

A claims workflow uses Amazon SQS. Poison messages are repeatedly failing and blocking useful retries. What should the architect configure? The team wants the control to be enforceable during normal operations.

Accepted Answer

A dead-letter queue with an appropriate maxReceiveCount. A dead-letter queue (DLQ) with an appropriate maxReceiveCount is the correct solution because it automatically moves messages that have failed processing a specified number of times to a separate queue, preventing them from blocking subsequent retries. This enforces control during normal operations by isolating poison messages without manual intervention, allowing the main queue to continue processing valid messages.

Answer

A FIFO queue without a redrive policy

Answer

Short polling instead of long polling

Answer

A larger message retention period only

Question 7

A trading dashboard stores uploaded documents in S3. The business requires a copy in another AWS Region for disaster recovery. What should be configured? The team wants the control to be enforceable during normal operations.

Accepted Answer

S3 Cross-Region Replication with versioning enabled. S3 Cross-Region Replication (CRR) automatically replicates objects to a destination bucket in a different AWS Region, providing a disaster recovery copy. Enabling versioning on both source and destination buckets is required for CRR to function, and replication can be enforced during normal operations by applying an IAM policy that denies `s3:PutObject` unless the request includes the `x-amz-server-side-encryption` header or by using a bucket policy that requires replication. This meets the business requirement for an enforceable, automated DR copy.

Answer

An EBS snapshot schedule

Answer

S3 lifecycle transition to Glacier Flexible Retrieval

Answer

A CloudFront distribution

Question 8

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? The team wants the control to be enforceable during normal operations.

Accepted Answer

A Lambda dead-letter queue or failure destination. A Lambda dead-letter queue (DLQ) or failure destination allows you to capture events that have exhausted all retry attempts from an asynchronous invocation. This ensures failed events are retained in Amazon SQS or SNS for later investigation, providing enforceable control during normal operations without impacting the function's ability to process successful events.

Answer

Lambda reserved concurrency set to zero

Answer

A larger deployment package

Answer

CloudFront error pages

Question 9

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? The team wants the control to be enforceable during normal operations.

Accepted Answer

Amazon EFS with mount targets in multiple Availability Zones. Amazon EFS provides a fully managed, POSIX-compliant NFS file system that can be mounted concurrently on multiple Linux EC2 instances across different Availability Zones. By creating mount targets in each AZ, the file system remains accessible even if one AZ fails, because the other mount targets continue to serve traffic. EFS also supports lifecycle policies and IAM enforcement to control access during normal operations, meeting the requirement for enforceable control.

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 10

A payments API requires point-in-time recovery and accidental-delete protection for a DynamoDB table. Which two settings should the architect enable? The team wants the control to be enforceable during normal operations.

Accepted Answer

Deletion protection or tightly controlled delete permissions. Deletion protection (Option A) prevents accidental table deletion by blocking drop-table operations, which is enforceable during normal operations. Point-in-time recovery (Option B) enables continuous backups with 35-day granularity, allowing restoration to any second within that window. Together, they satisfy the requirements for accidental-delete protection and point-in-time recovery.

Answer

Global secondary indexes

Answer

DAX

Question 11

A ticket booking system uses Aurora MySQL. The company wants fast cross-Region disaster recovery with low RPO. Which architecture should be considered? The team wants the control to be enforceable during normal operations.

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. It provides fast failover to a secondary Region and allows the primary Region to enforce write control during normal operations, meeting the low RPO and enforceable control requirements.

Answer

A single-AZ Aurora cluster

Answer

An ElastiCache Redis replica

Answer

Manual snapshots copied monthly

Question 12

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? The team wants the control to be enforceable during normal operations.

Accepted Answer

CloudFront caching with appropriate TTLs. CloudFront caching with appropriate TTLs allows the distribution to serve stale or cached content from edge locations even when the S3 origin is temporarily unavailable. By setting a minimum TTL (e.g., 0 seconds) and a default/max TTL (e.g., 86400 seconds), CloudFront can continue to respond to user requests with previously cached objects during an origin outage, ensuring high availability. This feature is enforceable during normal operations because the TTL settings are configured in the CloudFront distribution behavior and are always active, not just during failures.

Answer

AWS Backup Vault Lock

Answer

IAM Access Analyzer

Answer

S3 Select

Question 13

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? The team wants the control to be enforceable during normal operations.

Accepted Answer

Multi-AZ deployment for the RDS DB instance. Multi-AZ deployment for RDS MySQL provides synchronous standby replication across two Availability Zones. In the event of an AZ failure, Amazon RDS automatically fails over to the standby in the other AZ, ensuring availability with minimal application changes (the same database endpoint is used). This meets the requirement for enforceability during normal operations because Multi-AZ is always active, not a manual or scheduled process.

Answer

S3 Cross-Region Replication

Answer

EBS snapshots every hour

Answer

Read replicas only

Question 14

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? The team wants the control to be enforceable during normal operations.

Accepted Answer

Subnets in at least two Availability Zones with health checks enabled. Distributing EC2 instances across at least two Availability Zones (AZs) ensures that if one AZ fails, the Auto Scaling group can maintain capacity in the remaining AZ(s). Enabling health checks allows the group to detect instance failures and automatically replace them, providing fault tolerance. This configuration meets the requirement to tolerate a single AZ failure while remaining enforceable during normal operations.

Answer

A single EC2 instance with detailed monitoring

Answer

All instances in one larger subnet

Answer

A Network Load Balancer in one subnet

Question 15

A company runs a production MySQL database on Amazon RDS in us-east-1. A read replica exists in us-west-2 for disaster recovery. The primary region experiences a complete outage. Which of the following describes the correct procedure to restore database service using the cross-region read replica?

Accepted Answer

Manually promote the us-west-2 read replica to a standalone DB instance and update application endpoints. Cross-region RDS read replicas support manual promotion to a standalone database instance. When the primary region fails, the replica must be manually promoted — this makes it an independent writable instance in us-west-2.

Key points: Promotion is NOT automatic (unlike RDS Multi-AZ failover). Promotion breaks the replication link — the replica becomes autonomous. After promotion, application connection strings must be updated to the new endpoint. Any replication lag at the time of the outage represents potential data loss (RPO > 0).

Answer

Wait for AWS to automatically fail over the read replica to become the new primary

Answer

Restore the primary database from the most recent automated snapshot in us-west-2

Answer

Create a new RDS instance in us-west-2 and manually restore data from application logs