Free Amazon Web Services SAA-C03 Practice Exam with Questions & Answers | Set: 8

This design includes:

ALB: Supports AWS WAF integration.

Auto Scaling Group: Automatically scales based on load.

Multi-AZ Deployment: Increases resiliency and availability.

AWS WAF: Can be attached to ALB for application-layer protection.

“ALB is integrated with AWS WAF. You can deploy your EC2 instances in an Auto Scaling group across multiple Availability Zones to ensure high availability.”

— High Availability with Auto Scaling and ALB

Why not others?

A: Single AZ = not resilient

C: AWS WAF cannot attach to Route 53

D: NLB is not supported by AWS WAF

Amazon S3 Multi-Region Access Points allow applications to access S3 buckets in multiple Regions through a single global endpoint. This provides active-active read access with automatic routing to the closest bucket for low latency. With cross-Region replication, writes in the primary Region are automatically copied to the secondary Region, providing fault tolerance. Option A (CloudFront) provides caching and distribution, but does not address write replication or active-active bucket access. Option B (Transfer Acceleration) optimizes uploads across distances but does not enable cross-Region fault tolerance. Option C (AWS Backup) is designed for backup/restore, not real-time multi-Region reads and writes. Therefore, D is the correct solution for active-active read access and disaster recovery.

A warm pool is an Auto Scaling feature that keeps instances in a pre-initialized state so they can quickly join the active group when scaling is required. This reduces the time needed for instance bootstrapping and makes new capacity available almost instantly. Option A only increases capacity limits but does not address slow boot times. Option C merely extends grace periods without solving the delay. Option D forces overprovisioning, which is wasteful and not aligned with cost optimization. Using a warm pool (B) directly addresses the problem by reducing response time to scaling events.

AWS recommends Auto Scaling with dynamic scaling policies to handle unpredictable workload spikes. Target tracking scaling policies automatically adjust capacity based on defined metrics such as average CPU utilization or request count per target. This approach ensures applications maintain responsiveness without overprovisioning. Scheduled scaling (options B and C) is only effective when traffic patterns are predictable, which is not the case here. Reserved Instances or Spot Instances also do not address sudden demand changes effectively. Replacing the ALB with an NLB (D) does not solve latency caused by EC2 instance capacity. Therefore, using EC2 instances in an Auto Scaling group with a target tracking scaling policy is the most effective and cost-efficient solution for unpredictable, short-lived traffic spikes.

AWS guidance is to deploy one NAT gateway per Availability Zone for production workloads to improve resiliency and avoid cross-AZ dependency. However, the question explicitly says only production requires high availability. In non-production environments, the company can reduce cost by keeping a single NAT gateway and updating private-subnet route tables to use that remaining gateway. This saves hourly NAT gateway charges while preserving internet egress for private subnets. Reducing Availability Zones would affect more than NAT cost and would also weaken overall environment design. NAT instances add operational overhead compared with a managed NAT gateway. A transit gateway is unrelated to this cost problem. Therefore, keeping one NAT gateway per AZ for production and reducing to one NAT gateway in non-production is the most cost-effective answer.

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This solution addresses the scalability needs of the workload while preventing failed processing attempts due to resource constraints.

Amazon S3 event notificationscan be used to trigger a message to an SQS queue whenever a new video is uploaded.

The existing Auto Scaling group of EC2 instances can poll the SQS queue, ensuring that the EC2 instances only process videos when there is a job in the queue.

SQS decouplesthe video upload and processing steps, allowing the system to handle sudden spikes in video uploads without overloading EC2 instances.

The use ofAuto Scalingensures that the EC2 instances can scale in or out based on the demand, maintaining cost efficiency while avoiding processing failures due to insufficient resources.

AWS References:

S3 Event Notificationsdetails how to configure notifications for S3 events.

Amazon SQSis a fully managed message queuing service that decouples components of the system.

Auto Scaling EC2explains how to manage automatic scaling of EC2 instances based on demand.

Why the other options are incorrect:

A. AWS Lambda functions: While Lambda can handle some workloads, video processing is often resource-intensive and long-running, making EC2 a more suitable solution.

B. Using SNS with Lambda: Similar to A, Lambda is not ideal for large-scale video processing due to its time and memory limitations.

D. AWS Step Functions: While a valid orchestration solution, this introduces more complexity and overhead compared to the simpler SQS-based solution.

For the relational database tier, Amazon RDS Multi-AZ provides high availability with minimal manual intervention. In Multi-AZ mode, RDS maintains a synchronous standby in a different Availability Zone and provides automatic failover during certain failure scenarios. This reduces operational burden because the service handles replication, health monitoring, and failover orchestration.

For the container-based application tier, Amazon ECS with the Fargate launch type minimizes operational overhead because it removes the need to provision, patch, and scale the underlying EC2 instances that host containers. With Fargate, AWS manages the compute infrastructure, and the team focuses on task definitions, scaling policies, and application configuration. This supports a highly available, load-balanced architecture because ECS services can run tasks across multiple Availability Zones behind an Application Load Balancer, and scaling is managed via ECS Service Auto Scaling.

Option B describes read replicas, which are primarily used for scaling reads and, depending on configuration, may not provide the same automated failover characteristics as Multi-AZ for high availability. Read replicas are not a direct substitute for Multi-AZ HA. Option C (self-managed Docker cluster on EC2) is operationally heavy: you must manage node capacity, patching, cluster lifecycle, and scheduling. Option E (ECS on EC2) is a valid container platform but still requires managing EC2 instances, AMIs, and scaling/patching, which increases manual intervention compared to Fargate.

Therefore, combining RDS Multi-AZ (A) for database resilience and ECS Fargate (D) for serverless container operations meets the HA requirement with the least manual effort.

HPC workloads require high-throughput, low-latency networking, especially for tightly-coupled applications like weather modeling, genomics, or real-time rendering.

A cluster placement group places instances in the same Availability Zone and on physically connected hardware, reducing network latency and increasing throughput.

Elastic Fabric Adapter (EFA) is a network device for EC2 instances that enables low-latency, high-throughput networking using OS-bypass technology, ideal for tightly-coupled HPC applications.

Each instance can support single-flow 10 Gbps bandwidth using EFA, and collectively, the cluster can achieve up to 100 Gbps aggregate throughput when properly configured.

This solution supports the Performance Efficiency and Resilience design principles and is a standard AWS-recommended pattern for HPC.

???? References:

EC2 Placement Groups

Elastic Fabric Adapter Overview

Best Practices for HPC on AWS

If the SQS visibility timeout is set shorter than the time it takes for the application to process and delete the message, the message becomes visible to other consumers and can be processed again, resulting in duplicate processing. This is a common cause of duplicate messages when using SQS.

Reference Extract from AWS Documentation / Study Guide:

" If the visibility timeout for a message is set shorter than the time it takes to process the message, the message becomes visible again and can be received and processed again, resulting in duplicate processing. "

Source: AWS Certified Solutions Architect – Official Study Guide, SQS and Messaging section.

Option B (Amazon FSx for Lustre): FSx for Lustre is optimized for high-performance file systems required by HPC workloads, scaling to millions of IOPS and supporting parallelized data access.

Option E (Cluster Placement Group with Auto Scaling): A cluster placement group ensures low-latency communication between EC2 instances, critical for HPC workloads. Amazon EMR simplifies running large-scale analytics jobs.

Amazon FSx for Lustre Documentation,AWS Placement Groups Documentation

AmazonS3 with the Standard storage classis the best solution:

Encryption: SSE-S3 ensures server-side encryption of the data, meeting compliance requirements.

Immediate access: The Standard storage class provides low-latency and high-throughput access to data.

Multi-location storage: Cross-Region replication ensures data is stored in multiple AWS Regions for redundancy.

Why Other Options Are Not Ideal:

Option B:

Amazon EFS is more costly and suited for file systems rather than object storage.Not cost-effective.

Option C:

Amazon EBS is block storage and not optimized for object storage like PDFs. Backup schedules do not ensure immediate availability.Not suitable.

Option D:

S3 Glacier Flexible Retrieval is designed for archival, not immediate access.Does not meet access requirements.

AWS References:

Amazon S3 Standard Storage:AWS Documentation - S3 Storage Classes

Amazon S3 Cross-Region Replication:AWS Documentation - Cross-Region Replication

AWS Encryption Options:AWS Documentation - S3 Encryption

AWS best practice for a highly available, resilient web application is:

Run EC2 instances in an Auto Scaling group across multiple Availability Zones.

Put an Application Load Balancer (ALB) in front of the Auto Scaling group.

Use CloudWatch alarms and scaling policies for horizontal scaling based on demand.

Option D implements exactly this: a minimum of three instances spread across AZs (resilience to AZ failure), behind an ALB, with automatic horizontal scaling. This provides both elasticity and high availability with good cost efficiency (instances scale out/in based on traffic).

Option A uses only three fixed instances and relies on vertical scaling, which does not scale as well and is less resilient.

Option B overprovisions to nine instances from the start, which is unnecessarily expensive.

Option C keeps all instances in a single AZ, which does not meet resilience requirements.

Using API Gateway and Lambda enables serverless handling of form submissions with minimal cost and infrastructure. When coupled with Amazon SNS, it allows instant email notifications without running servers, making it ideal for low-traffic workloads.

The lowest-overhead answer isAPI Gateway with direct AWS service integration to DynamoDB PutItem. DynamoDB’s API includes a native PutItem action for writing an item to a table, and API Gateway supports direct AWS service integrations, which lets the web application send requests through an API layer without developers touching DynamoDB directly. This approach is scalable, reusable, and avoids managing Lambda code purely as a pass-through layer. The SQS-based design adds unnecessary queueing for a straightforward write API, and ALB is not the appropriate frontend for invoking DynamoDB actions. Therefore, direct API Gateway service integration is the cleanest design.

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Compute Savings Plans apply to EC2, AWS Fargate, and AWS Lambda usage, maximizing coverage for mixed architectures while retaining flexibility across instance families, regions, OS, and tenancy. For private connectivity, Lambda functions must be configured with VPC access to attach ENIs in the target subnets, enabling direct network access to EC2 in private subnets (no public subnets are required for intra-VPC communication). EC2 Instance Savings Plans only discount EC2 usage and are tied to a specific instance family in a region, reducing flexibility and leaving Lambda costs undiscounted. Keeping Lambda in the service VPC prevents direct access to private EC2 without VPC configuration. Thus, a 1-year Compute Savings Plan plus connecting Lambda to the private subnets minimizes total cost and meets connectivity needs.

Business-critical applications often require predictable, low-latency I/O and high durability. Provisioned IOPS SSD (io1 or io2) Amazon EBS volumes are specifically engineered for these workloads.

Option C provides consistent, high-performance storage with guaranteed IOPS and low latency. EBS volumes are network-attached and persist independently of the EC2 instance lifecycle, ensuring durability and data protection. Provisioned IOPS volumes are commonly used for databases, transactional systems, and latency-sensitive applications.

Option A (instance store) offers low latency but is ephemeral and loses data on instance stop or failure. Option B is in-memory caching and not durable storage. Option D is optimized for large, sequential workloads and does not provide consistent low latency.

Therefore, C is the correct choice because it delivers the required performance, durability, and reliability for mission-critical applications.

Why Option B is Correct:

HTTP Proxy Integration: Passes XML requests directly to the application, which already supports XML.

JSON Conversion: An AWS Lambda function converts JSON requests to XML and calls the application.

API Gateway: Acts as a front end to handle JSON requests and integrates seamlessly with Lambda for the transformation process.

Why Other Options Are Not Ideal:

Option A: Suggests using API Gateway mappings to convert JSON to XML. API Gateway mapping templates are limited in functionality and are not ideal for complex transformations.

Option C and D: Use HTTP custom integration unnecessarily, which adds complexity without additional benefits.

AWS References:

Amazon API Gateway Integration:AWS Documentation - API Gateway Integration

AWS Lambda:AWS Documentation - Lambda

AWS guidance for NAT Gateway recommends deploying “a NAT gateway in each Availability Zone and configure your routing to ensure that resources use the NAT gateway in the same Availability Zone.” This provides “zone-independent architecture” and avoids cross-AZ data processing charges and single-AZ failures. Option B creates a single point of failure and incurs cross-AZ egress charges when private subnets in other AZs traverse a centralized NAT. NAT instances (C) are legacy, require manual scaling/failover/patching, and are not recommended for production HA. Option D is not supported (NLB cannot front a NAT Gateway as a target). With steady, uniform load, per-AZ NAT Gateways deliver high availability with predictable cost; routing each private subnet to its local NAT Gateway maintains security (no inbound initiated connections) and resilience. This meets the requirement for cost-effective, secure outbound connectivity across multiple AZs while preserving availability.

Auto Scalingis the most effective solution for ensuring seamless scalability of a stateless application. Key points:

Dleverages Auto Scaling with a Spot Fleet for cost efficiency and attaches an ALB to distribute traffic.

A and Bdo not provide automated scaling and would require manual intervention to add more instances.

Cchanges the instance type but does not scale out horizontally, which is required here.

AWS Documentation Reference:

Amazon EC2 Auto Scaling

AWS Global Accelerator is the best answer because it providesstatic anycast IP addressesand routes users to the optimal healthy endpoint over the AWS global network. AWS documentation explains that Global Accelerator continuously monitors endpoint health and redirects traffic to the next best healthy endpoint almost immediately, which avoids dependence on DNS resolver caching or client-side IP caching. That is especially important for low-latency global applications such as Voice over IP. Route 53 geolocation routing does not provide the same fast failover characteristics, and CloudFront is not the service for generic bidirectional VoIP application traffic. (docs.aws.amazon.com)

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