SAA-C03 Design Resilient Architectures Practice Test 5 — 15 Questions

Question 1

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? 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

Route 53 failover routing with health checks. Route 53 failover routing with health checks is correct because it provides the DNS-level automatic failover mechanism required to redirect traffic from the primary Region to a secondary Region when the primary endpoint becomes unhealthy. Route 53 health checks monitor the primary endpoint's health, and when they detect a failure, the failover routing policy automatically returns the IP address of the secondary endpoint, enabling seamless failover without manual intervention. This is a managed AWS-native control that meets the architecture review board's preference.

Answer

S3 Transfer Acceleration

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AWS Organizations service control policies

Question 2

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? 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, meaning each message is delivered at least once but may be delivered more than once. This aligns perfectly with the requirement that every event must be processed at least once and that duplicate processing is acceptable if consumers are idempotent. SQS is a fully managed, AWS-native service that meets the architecture review board's preference for a managed solution.

Answer

Use an in-memory queue on one EC2 instance

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Use UDP messages sent directly to workers

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Use CloudFront signed URLs

Question 3

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 architecture review board prefers a managed AWS-native control.

Accepted Answer

Multi-AZ deployment for the RDS DB instance. Multi-AZ deployment for RDS MySQL provides synchronous standby replication to a different Availability Zone. In the event of an AZ failure, RDS automatically fails over to the standby, ensuring high availability with minimal application changes (the same endpoint is used). This is a managed AWS-native solution that meets the architecture review board's preference.

Answer

S3 Cross-Region Replication

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EBS snapshots every hour

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Read replicas only

Question 4

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? The architecture review board prefers a managed AWS-native control.

Accepted Answer

Route 53 failover routing with health checks. Route 53 failover routing with health checks (Option B) is required because it monitors the primary endpoint's health and automatically reroutes traffic to a secondary Region when the primary becomes unhealthy. This is the managed AWS-native control for DNS-based failover, meeting the architecture review board's preference.

Answer

AWS Organizations service control policies

Answer

S3 Transfer Acceleration

Question 5

A claims workflow requires point-in-time recovery and accidental-delete protection for a DynamoDB table. Which two settings should the architect enable? The architecture review board prefers a managed AWS-native control.

Accepted Answer

Point-in-time recovery. Point-in-time recovery (PITR) for DynamoDB enables continuous backups with 35-day granularity, allowing restoration to any second within that window. This satisfies the point-in-time recovery requirement by providing a managed AWS-native control that automatically backs up table data without manual intervention.

Answer

DAX

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Global secondary indexes

Question 6

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.

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

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AWS Backup Vault Lock

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S3 Select

Question 7

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 8

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

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A Network Load Balancer in one subnet

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A single EC2 instance with detailed monitoring

Question 9

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.

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AWS WAF

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Amazon CloudFront

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Amazon Route 53 weighted routing

Question 10

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

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S3 lifecycle transition to Glacier Flexible Retrieval

Answer

A CloudFront distribution

Question 11

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 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? 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 13

A company uses Amazon SQS and AWS Lambda to process orders. Lambda typically completes in 4 minutes, but complex orders can take up to 12 minutes. The team reports that some orders are being processed more than once. Which is the MOST likely cause and the recommended fix?

Accepted Answer

Increase the SQS queue visibility timeout to exceed the maximum Lambda processing time. SQS visibility timeout defines how long a message is hidden from other consumers after it is received. If a Lambda function takes longer than the visibility timeout to process a message, the message becomes visible again and another Lambda invocation picks it up — causing duplicate processing.

The default SQS visibility timeout is 30 seconds. If processing takes 12 minutes but visibility timeout is 30 seconds, messages reappear and are processed again. The fix is to increase the visibility timeout to exceed the maximum processing time — at least 13-15 minutes.

Answer

Enable SQS FIFO queue to prevent duplicate message delivery

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Reduce the Lambda function timeout to 4 minutes to match typical processing time

Answer

Enable SQS long polling to reduce the frequency of message retrieval

Question 14

A company is designing a highly available web application on AWS. The application runs on Amazon EC2 instances behind an Application Load Balancer (ALB) and uses an Amazon RDS Multi-AZ DB instance. Which three design choices would improve the application's resilience against an AWS Availability Zone failure? (Choose three.)

Accepted Answer

Enable Amazon RDS Multi-AZ deployment for automatic failover to a standby in a different Availability Zone.. The provided explanation for deploying EC2 instances across AZs is accurate and correctly justifies that design choice. However, the overall question structure is flawed due to the contradiction between the stem and one of the marked correct options regarding 'improvement'.

Answer

Provision EC2 instances in a single Availability Zone and use Auto Scaling to replace failed instances.

Answer

Configure the ALB as a Network Load Balancer for faster failover.

Answer

Use Amazon Route 53 health checks with a failover routing policy to redirect traffic to a different Region.

Question 15

A company is migrating a legacy monolithic application to AWS and wants to improve its resilience by decoupling components. The application currently writes directly to a shared file system and uses synchronous HTTP calls between modules. Which three AWS services should the company use to achieve a more resilient, decoupled architecture? (Choose three.)

Accepted Answer

Amazon SQS for asynchronous message passing between application components.. Amazon SQS is correct because it enables asynchronous message passing between application components, decoupling them so that a failure in one component does not block others. This replaces the synchronous HTTP calls, improving resilience by allowing messages to be buffered and processed independently. Amazon SNS is correct because it facilitates event-driven architectures by allowing components to publish events to topics, which are then fanned out to multiple subscribers. This further decouples components as publishers do not need to know about specific subscribers, enhancing resilience and scalability. AWS Lambda is correct because it allows components to be re-architected as stateless, serverless functions. This inherently promotes decoupling by removing state dependencies between instances and provides automatic scaling and high availability, significantly improving the overall resilience and agility of the application.

Answer

Amazon EFS as a shared file system to replace the on-premises NAS.

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AWS Direct Connect to provide a dedicated network link for inter-component communication.

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Amazon Elastic Block Store (EBS) with Multi-Attach for shared block storage between components.