SAA-C03 Design Resilient Architectures Practice Test 3 — 15 Questions

Question 1

An architect is designing a system that must be resilient against AWS regional failure. Which AWS service is best suited to manage global DNS traffic and provide health-based routing?

Accepted Answer

Amazon Route 53.. Route 53 is a highly available and scalable cloud Domain Name System (DNS) web service. It provides health checks and routing policies, such as failover, latency-based, and geolocation routing. By using health checks, Route 53 can detect the failure of an endpoint in one region and automatically route traffic to a healthy endpoint in another, fulfilling the requirement for regional resilience.

Answer

Elastic Load Balancing (ELB).

Answer

AWS Direct Connect.

Answer

Amazon CloudFront.

Question 2

Refer to the exhibit. The current IAM policy allows an EC2 instance to read backups. The architect wants to ensure the data is recoverable if the source bucket is compromised by an external actor with write access. What should be done?

Accepted Answer

Enable S3 Object Lock on the bucket.. S3 Object Lock enforces a Write Once Read Many (WORM) model, preventing objects from being deleted or overwritten for a specified retention period — even by users with full administrative permissions. This directly addresses the scenario where an external actor with write access could otherwise overwrite or delete backups, ensuring the data remains recoverable. Object Lock requires versioning to be enabled on the bucket.

Answer

Apply a Bucket Policy to deny s3:PutObject for all users.

Answer

Create a read-only IAM user for the EC2 instance.

Answer

Enable S3 Server-Side Encryption (SSE-S3).

Question 3

An application consists of a web tier and an application tier. The web tier must be accessible from the internet, but the application tier must remain private. How should the architect configure the network for maximum resilience?

Accepted Answer

Deploy web and app tiers across multiple subnets in multiple AZs, with app tiers in private subnets.. For maximum resilience, the web and application tiers should be deployed across multiple subnets in multiple Availability Zones, with the web tier in public subnets (accessible from the internet) and the application tier in private subnets (not directly accessible). This design ensures high availability and fault tolerance, and follows the principle of least privilege by isolating the private tier.

Answer

Deploy all tiers in a single public subnet in one AZ.

Answer

Put everything in a public subnet and use Security Groups for isolation.

Answer

Use a single private subnet for both tiers and a NAT Gateway in the same subnet.

Question 4

An application processes large batches of data from an S3 bucket. The process can take hours. If an instance fails, the batch is lost. Which design pattern ensures the most resilient batch processing?

Accepted Answer

Use an SQS queue to store tasks and an Auto Scaling group to process them.. Using an SQS queue to decouple the producer and consumer is the ideal pattern. The S3 event notification sends a message to the queue, and instances poll the queue for tasks. If an instance fails, the message becomes visible again in the queue after the visibility timeout, allowing another instance to pick up the task and resume processing.

Answer

Use an Auto Scaling group with a single instance to process the S3 files sequentially.

Answer

Directly trigger Lambda functions from S3 and increase the timeout.

Answer

Use a single large EC2 instance to process the data in memory.

Question 5

A solutions architect is designing a mission-critical web application that runs on Amazon EC2 instances behind an Application Load Balancer. The application must remain available even if an entire AWS Region experiences a catastrophic failure. The RPO must be near zero, and the RTO must be less than 15 minutes. Which disaster recovery strategy should the architect implement?

Accepted Answer

Configure a multi-site active-active deployment spanning two AWS Regions with continuous data replication and Route 53 health checks.. A multi-site active-active deployment spanning two AWS Regions with continuous data replication and Route 53 health checks provides near-zero RPO and sub-15-minute RTO by allowing both regions to serve traffic simultaneously. If one region fails, Route 53 automatically redirects traffic to the healthy region, ensuring continuous availability.

Answer

Implement a backup and restore strategy using automated daily Amazon EBS snapshots copied to a secondary AWS Region.

Answer

Deploy a pilot light strategy by maintaining a minimal footprint of core database and configuration services in a secondary Region.

Answer

Set up a warm standby architecture running a scaled-down version of the entire application stack in a secondary Region.

Question 6

A company is designing a high-throughput, fault-tolerant payment processing system running on Amazon EC2 instances across multiple Availability Zones. The architecture must withstand the sudden failure of any single AZ without dropping active database transactions or corrupting state. Which TWO design practices should the solutions architect implement?

Accepted Answer

Deploy an Amazon Aurora database cluster configured across multiple Availability Zones with an automatic failover replica.. Deploying the EC2 instances across an Auto Scaling group spanning multiple Availability Zones ensures compute capacity automatically rebalances during failures. Utilizing Amazon Aurora Multi-AZ deployments provides high availability and automatic failover for relational databases. Together, these practices protect both the compute and data tiers from localized outages.

Answer

Store application state files on a single Amazon EBS General Purpose SSD attached to the primary EC2 instance.

Answer

Configure an Amazon Route 53 latency-based routing policy to direct user traffic directly to EC2 instances in each zone.

Answer

Pin all payment processing worker threads to a single static EC2 instance to simplify debugging and transaction logging.

Question 7

A media streaming company stores millions of video assets in an Amazon S3 bucket. Compliance regulations mandate that objects must be protected against accidental deletion, malicious tampering, and region-wide disasters. The solution must prevent permanent deletion even by users with root credentials during a retention period. Which combination of features meets these requirements?

Accepted Answer

Enable S3 Versioning, configure S3 Object Lock in compliance mode, and set up S3 Cross-Region Replication to another AWS Region.. Enabling S3 Versioning preserves every version of every object, protecting against accidental overwrites and deletions. Configuring S3 Object Lock in compliance mode ensures that objects cannot be deleted or modified by any user, including the root account, until the retention period expires. Finally, S3 Cross-Region Replication protects against catastrophic regional disasters by maintaining synchronized copies.

Answer

Enable S3 Versioning, apply an S3 Lifecycle rule to transition objects to S3 Glacier, and configure AWS Backup vaults.

Answer

Apply strict AWS Identity and Access Management (IAM) bucket policies denying s3:DeleteObject, and enable server-side encryption.

Answer

Configure Amazon S3 Intelligent-Tiering, enable Multi-Factor Authentication (MFA) Delete, and attach bucket policies.

Question 8

A global e-commerce enterprise runs its checkout workflow using AWS Lambda functions integrated with Amazon API Gateway. During flash sales, traffic spikes cause downstream payment APIs to timeout, leading to lost transactions and frustrated customers. The solutions architect needs to redesign the architecture to decouple the frontend from the payment processor and ensure no transaction requests are lost. What should the architect do?

Accepted Answer

Integrate an Amazon SQS FIFO queue between API Gateway and the downstream payment processing Lambda functions.. Integrating an Amazon SQS FIFO queue between API Gateway and the payment Lambda decouples the frontend from the downstream payment processor, buffering requests during traffic spikes so no transaction is lost. FIFO queues preserve order and provide exactly-once processing, which is critical for payment transactions. The Lambda functions can then poll the queue at a controlled rate, preventing downstream timeouts.

Answer

Configure API Gateway to cache responses using an Amazon ElastiCache Redis cluster deployed in multi-AZ mode.

Answer

Increase the timeout and memory allocation of the API Gateway integration and the AWS Lambda functions.

Answer

Use AWS Step Functions with standard workflows to execute the payment processing steps sequentially.

Question 9

Refer to the exhibit. A solutions architect reviewed an AWS CloudFormation template used to deploy an Auto Scaling group for a production web application. During an AWS Availability Zone outage in us-east-1, users experienced partial application downtime even though the Auto Scaling group reported instances running. Why is this architecture failing resiliency best practices?

Accepted Answer

The Auto Scaling group defines Availability Zones directly instead of referencing subnets across multiple zones.. For an Auto Scaling group to survive an Availability Zone outage, it must launch instances across multiple subnets in different AZs. When the ASG specifies Availability Zones directly (or uses a single subnet), all instances land in one AZ, so an AZ failure takes down the entire fleet even though the ASG still reports 'running' instances in the failed zone. Referencing subnets across multiple AZs lets the ASG rebalance and launch replacements in healthy zones.

Answer

The Launch Template version is hardcoded to version 1 instead of using $Latest or $Default.

Answer

The MinSize and DesiredCapacity are set too low to handle sudden spikes in traffic during an outage.

Answer

The Auto Scaling group is missing a health check type configuration set to ELB instead of EC2.

Question 10

A web application runs on Amazon EC2 instances managed by an Auto Scaling group across three Availability Zones behind an Application Load Balancer. The application performs heavy computations that consume high CPU resources. Users report intermittent 504 Gateway Timeouts during peak hours. The solutions architect notices that newly launched instances take several minutes to bootstrap before they can serve traffic. How should the architect resolve this issue?

Accepted Answer

Implement pre-baked Amazon Machine Images (AMIs) with application code pre-installed and configure an Auto Scaling health check grace period.. Pre-baked AMIs eliminate the lengthy bootstrap process by having the application code and dependencies already installed, so new instances can serve traffic almost immediately. Configuring an appropriate health check grace period ensures the ASG does not terminate instances prematurely during any remaining startup time, while allowing ELB health checks to replace truly unhealthy instances. This combination reduces the window where the ASG is scaling out but new instances are not yet ready, mitigating 504 errors.

Answer

Configure an Amazon SQS queue in front of the EC2 instances to offload computational tasks asynchronously.

Answer

Switch the load balancer from an Application Load Balancer to a Network Load Balancer for faster TCP packet routing.

Answer

Decrease the Auto Scaling group health check grace period to zero so failing instances are replaced immediately.

Question 11

A company is designing a mission-critical database architecture using Amazon RDS. Which TWO steps should the architect take to ensure high availability and data durability? (Select TWO.)

Accepted Answer

Enable Multi-AZ deployment for the RDS instance.. Option A is correct because an RDS Multi-AZ deployment maintains a synchronous standby replica in a different Availability Zone, and RDS automatically fails over to that standby if the primary instance or its AZ fails, which directly provides high availability for a mission-critical database. Option C is correct because enabling automated backups with a defined retention period gives point-in-time recovery (PITR) to any second within the retention window (up to 35 days), which ensures data durability and recoverability from corruption or accidental deletion. Option B is not appropriate because a Read Replica in the same AZ is asynchronous, does not provide automatic failover, and would not survive an AZ-level outage. Option D is incorrect because gp2 is just one storage option and choosing it does not by itself deliver high availability or durability. Option E is incorrect because disabling deletion protection increases the risk of accidental data loss rather than protecting the database.

Answer

Configure a Read Replica in the same Availability Zone.

Answer

Set the storage type to General Purpose SSD (gp2) only.

Answer

Disable the deletion protection feature for all instances.

Question 12

A web application stores static files in Amazon S3. Due to regulatory requirements, the company must ensure that the files are replicated to a secondary region. What is the most efficient way to achieve this?

Accepted Answer

Enable S3 Cross-Region Replication on the source bucket.. S3 Cross-Region Replication (CRR) is the most efficient and native way to automatically replicate objects from a source bucket to a destination bucket in a different region. It replicates new objects as they are uploaded and can also replicate existing objects if configured, providing a managed, low-latency replication solution that meets regulatory requirements.

Answer

Use AWS DataSync to copy files periodically.

Answer

Create an EventBridge rule to trigger a Lambda function for every upload.

Answer

Use AWS Storage Gateway to replicate local data to S3.

Question 13

A mission-critical application requires a recovery time objective (RTO) of near-zero. Which disaster recovery strategy should the architect implement?

Accepted Answer

Multi-Site Active-Active.. The explanation is accurate, but the question requires a defined exam trap and common trap note to help students avoid pitfalls.

Answer

Backup and Restore.

Answer

Pilot Light.

Answer

Warm Standby.

Question 14

An organization needs to improve the resilience of its EC2-based application. Which THREE actions should the architect perform? (Select THREE.)

Accepted Answer

Distribute EC2 instances across multiple Availability Zones.. Option A is correct because distributing EC2 instances across multiple Availability Zones ensures the application survives the failure of an entire AZ, since each AZ has independent power, cooling, and networking. Option B is correct because an Auto Scaling group continuously performs health checks and automatically replaces unhealthy instances, restoring capacity without manual intervention. Option D is correct because load balancer health checks detect unhealthy targets and stop routing traffic to them, so users are only sent to functioning instances. Option C is wrong because a single large instance is a single point of failure and does not improve resilience. Option E is wrong because a fixed-capacity Auto Scaling group cannot scale out to absorb load or compensate for lost capacity, so it does not meaningfully improve resilience.

Answer

Use a single large EC2 instance instead of multiple smaller ones.

Answer

Place all instances in a single Auto Scaling group with a fixed capacity.

Question 15

An application uses Amazon DynamoDB. To ensure the application remains resilient to regional outages, what is the best approach?

Accepted Answer

Use DynamoDB Global Tables.. DynamoDB Global Tables provide multi-region, active-active replication with automatic conflict resolution, ensuring the application can read and write to the table in any region and remain resilient to regional outages. This is the only option that offers automatic, low-latency replication across regions without manual intervention.

Answer

Enable DynamoDB backups in the same region.

Answer

Use AWS Database Migration Service to sync data.

Answer

Manually replicate data to another region every hour.