Question 493 of 247
SOA-C02 Cost and Performance Optimization Practice Question
A company runs a critical web application on Amazon EC2 instances behind an Application Load Balancer (ALB). The application is deployed in a single AWS region. The company wants to improve performance for users in other regions and reduce the load on the origin servers. The SysOps administrator decides to use Amazon CloudFront. After implementing CloudFront, the administrator notices that the cache hit ratio is very low (around 10%) for the dynamic API responses that are served by the application. These API responses are personalized per user and change frequently. The administrator wants to improve performance for these dynamic requests while still using CloudFront. The application uses cookies for session management and the API responses depend on the user's session. The administrator must ensure that users receive the correct personalized content. Which configuration should the administrator use?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use Lambda@Edge to generate personalized responses at the edge without forwarding all requests to the origin.
For dynamic, personalized API responses that depend on user session cookies, caching is ineffective because each user's response is unique. Lambda@Edge allows you to run code at CloudFront edge locations to generate personalized responses or modify requests/responses. By using a Lambda function that inspects the session cookie and generates the appropriate API response at the edge, you can serve personalized content without forwarding every request to the origin. This improves performance by reducing round trips and origin load while ensuring users receive correct personalized content. Options B, C, and D do not effectively address the need for dynamic personalization with low cache hit ratio.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Use Lambda@Edge to generate personalized responses at the edge without forwarding all requests to the origin.
Why this is correct
Use Lambda@Edge to generate personalized responses at the edge. This allows dynamic content to be served from the edge without requiring a round trip to the origin, improving performance while maintaining correctness. It directly addresses the low cache hit ratio by avoiding caching altogether for personalized content.
- ✗
Configure CloudFront to use origin shield and enable keep-alive connections to the origin.
Why it's wrong here
Configuring Origin Shield and keep-alive connections can improve efficiency for cacheable content but does not help with dynamic, non-cacheable responses. Origin Shield adds an additional layer that may increase latency for cache misses and does not solve the issue of personalization.
- ✗
Configure CloudFront to forward cookies to the origin and enable caching based on cookies.
Why it's wrong here
Forwarding cookies and enabling caching based on cookies would result in a separate cache entry per user session, leading to many cache misses and very low cache hit ratio. This would not improve performance and could increase complexity.
- ✗
Disable caching for the API behavior in CloudFront and enable real-time logs.
Why it's wrong here
Disabling caching for the API behavior forces every request to traverse to the origin, eliminating any potential edge-level caching and thereby increasing both origin load and end-user latency. Real-time logs stream request data to a monitoring service like CloudWatch or Kinesis, which is purely observational and does not influence content delivery or cache behavior. This combination fails to improve the cache hit ratio or reduce origin round trips, leaving the core problem of dynamic personalized content unaddressed and instead degrading overall performance.
Quick reference
Cloud Service Model Comparison
| Model | You Manage | Provider Manages | Examples |
|---|---|---|---|
| IaaS | OS, runtime, apps, data | Hardware, hypervisor, networking | EC2, Azure VMs, GCP Compute Engine |
| PaaS | Apps and data | OS, runtime, middleware, hardware | Elastic Beanstalk, Azure App Service |
| SaaS | Data and settings only | Everything else | Microsoft 365, Salesforce, Workday |
| FaaS / Serverless | Function code only | Infra, scaling, runtime | Lambda, Azure Functions, Cloud Run |
| CaaS | Containers and apps | Kubernetes, OS, hardware | EKS, AKS, GKE |
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Last reviewed: Jun 20, 2026
This SOA-C02 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the SOA-C02 exam.
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