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

Question 1

An internal API is deployed in two AWS Regions behind separate Application Load Balancers. The company wants clients to use the primary Region when it is healthy and automatically switch to the secondary Region if the primary health check fails. Which two Route 53 record configurations are required? Select two.

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

Accepted Answer

Create a primary failover record that points to the primary ALB and associates a Route 53 health check.. A primary failover record in Amazon Route 53 directs traffic to the primary ALB and is associated with a Route 53 health check. If the health check fails, Route 53 automatically fails over to the secondary failover record, ensuring high availability across Regions.

Answer

Create a weighted record set that sends 50 percent of traffic to each Region.

Answer

Create a latency-based record set so Route 53 always prefers the fastest Region.

Answer

Create a multivalue answer record to return both ALB addresses on each lookup.

Question 2

Based on the exhibit, the team wants to stop poison messages from consuming worker capacity and also prevent duplicate side effects if the same message is delivered more than once. Which design change best meets the requirement?

Accepted Answer

Configure a dead-letter queue and make the handler idempotent by storing a durable processed-message key.. A dead-letter queue isolates poison messages that repeatedly fail processing, preventing them from consuming worker capacity. Making the handler idempotent by storing a durable processed-message key (e.g., using DynamoDB or a database) ensures that even if the same message is delivered more than once, duplicate side effects are avoided. This combination directly addresses both requirements: stopping poison messages from wasting resources and preventing duplicate processing.

Answer

Increase the SQS queue batch size so each worker processes more messages per request.

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Replace SQS with Amazon SNS and let each worker subscribe directly to the topic.

Answer

Disable retries and shorten the visibility timeout so failed messages disappear sooner.

Question 3

Based on the exhibit, a faulty deployment corrupted production data at 10:30 UTC and the issue was discovered at 10:55 UTC. The team needs to recover the database to the last good state before the corruption. Which action should they take?

Accepted Answer

Use point-in-time restore to create a new database instance at 10:29 UTC, then switch the application to it.. Amazon RDS for MySQL (and other engines) supports point-in-time recovery (PITR), which allows you to restore a database to any second within the backup retention period, up to the last five minutes. By restoring to 10:29 UTC (one minute before the corruption at 10:30 UTC), the team can recover the database to its last good state with minimal data loss. After restoring, the application can be pointed to the new instance, avoiding the corrupted data.

Answer

Restore the latest manual snapshot and accept data loss since the snapshot was taken overnight.

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Restart the database instance so the transaction log replays the failed migration cleanly.

Answer

Create a read replica and promote it, because replicas always contain the previous transaction state.

Question 4

Based on the exhibit, the application team wants the database to keep the same connection endpoint during failover and to reconnect automatically after the primary instance becomes unavailable. Which change best meets the requirement?

Accepted Answer

Replace the IP address with the RDS DNS endpoint and add client retry logic that re-resolves DNS after connection loss.. Using the RDS DNS endpoint ensures that the application connects to the current primary instance, even after a failover. When the primary becomes unavailable, RDS promotes a standby (or read replica) to a new primary and updates the DNS record to point to the new instance's IP. By adding client retry logic that re-resolves DNS after a connection loss, the application automatically picks up the new IP and reconnects without manual intervention, meeting both requirements of a stable endpoint and automatic reconnection.

Answer

Keep the IP address and increase the JDBC connection timeout so the application waits longer during failover.

Answer

Create an additional read replica and point the application to it so failover is faster.

Answer

Place a Network Load Balancer in front of the database and use the load balancer target IP to avoid DNS changes.

Question 5

Based on the exhibit, which Route 53 configuration should be used so traffic automatically returns to the secondary Region only when the primary Region becomes unhealthy?

Accepted Answer

Use failover routing with a primary alias record, a secondary alias record, and a Route 53 health check on the primary target.. Failover routing in Amazon Route 53 is designed for active-passive configurations. By creating a primary alias record pointing to the ALB in the primary Region and a secondary alias record pointing to the ALB in the secondary Region, and attaching a Route 53 health check to the primary target, traffic automatically fails over to the secondary Region only when the health check detects the primary as unhealthy. This meets the requirement of returning traffic to the secondary Region only upon primary failure.

Answer

Use latency-based routing with both ALB records enabled.

Answer

Use geolocation routing so users are always sent to the closest Region.

Answer

Use a CNAME record that points to both ALBs so DNS can round-robin between Regions.

Question 6

Based on the exhibit, the application should continue serving requests if one Availability Zone fails. Which change best improves resilience with the least operational complexity?

Accepted Answer

Add at least one subnet from a second Availability Zone to both the ALB and the Auto Scaling group.. Adding subnets from a second Availability Zone to both the ALB and the Auto Scaling group distributes the application across multiple AZs. This ensures that if one AZ fails, the ALB can route traffic to healthy targets in the remaining AZ, and the Auto Scaling group can maintain capacity by launching instances in the surviving AZ. This approach directly addresses the requirement to continue serving requests during an AZ failure with minimal operational complexity.

Answer

Increase the desired capacity in AZ-a so more instances can absorb the failure of that same Availability Zone.

Answer

Disable health checks so the ALB stops removing targets during brief infrastructure issues.

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Move the application to a single larger instance type so the fleet has fewer moving parts.

Question 7

Based on the exhibit, some SQS messages fail validation repeatedly and continue consuming worker time. What change best prevents the bad messages from being retried forever?

Accepted Answer

Configure a dead-letter queue and a redrive policy for messages that exceed the retry limit.. A dead-letter queue (DLQ) with a redrive policy allows messages that have been received a maximum number of times (e.g., after the configured retry limit) to be moved to a separate queue for analysis or manual handling. This prevents the same invalid message from being repeatedly processed by workers, freeing up compute resources and avoiding infinite retry loops.

Answer

Increase the visibility timeout so each message has more time to finish processing.

Answer

Replace the queue with an Amazon SNS topic so failed messages will not be retried.

Answer

Increase the number of workers so the queue drains faster during peak load.

Question 8

Based on the exhibit, the web team wants the application to continue serving traffic if one Availability Zone fails. Which change best meets the requirement with the least operational overhead?

Accepted Answer

Add the unused subnet in us-east-1b to the Auto Scaling group so instances can launch in both AZs.. It adds the unused subnet in us-east-1b to the Auto Scaling group, enabling EC2 instances to launch across two Availability Zones. This provides fault isolation: if one AZ fails, the ALB can route traffic to healthy instances in the other AZ. The change requires only a configuration update to the Auto Scaling group, minimizing operational overhead while meeting the high-availability requirement.

Answer

Increase desired capacity to 3 in the same Availability Zone so one extra instance is always available.

Answer

Replace the Application Load Balancer with a Network Load Balancer because it will automatically keep the app online.

Answer

Move the application to a larger EC2 instance type so a single server can handle the full workload.

Question 9

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?

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 only needs to reconnect to the same endpoint). This meets the requirement for availability during an AZ outage without requiring code modifications.

Answer

S3 Cross-Region Replication

Answer

Read replicas only

Answer

EBS snapshots every hour

Question 10

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. 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

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A Network Load Balancer in one subnet

Answer

A single EC2 instance with detailed monitoring

Question 11

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

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Amazon CloudFront

Answer

Amazon Route 53 weighted routing

Question 12

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. 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 13

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 14

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 15

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