Amazon Web Services Updated SAA-C03 Exam Questions and Answers by sufyan

This architecture uses ALB for routing, Auto Scaling for elasticity, SQS to buffer unprocessed orders and decouple services, and RDS Multi-AZ for high availability and durability of transactional data. This ensures resilience and fault tolerance even during traffic spikes.

AWS X-Ray is the AWS service designed for distributed tracing, giving end-to-end visibility into how requests flow through microservices, APIs, and serverless components. It provides service maps, latency breakdowns, and performance insight per service, which is exactly what is required.

To use X-Ray effectively, each application stack must be instrumented. For infrastructure deployed through AWS CloudFormation, best practice is to enable and configure X-Ray in the CloudFormation templates (for Lambda, API Gateway, ECS, etc.). That way, all teams and stacks have consistent tracing enabled as part of their IaC.

Control Tower (Option B) cannot “turn on” X-Ray tracing inside applications; it only helps with account setup and guardrails.

CloudTrail (Option A) is for audit logging of API calls, not performance tracing.

CloudWatch (Option C) provides metrics and logs, but not request-level distributed tracing across multiple services.

AWS WAF has limits on how much of an HTTP request body it can inspect. When requests exceed the inspectable size, AWS WAF treats the body as oversize relative to the configured inspection limits, which can lead to rules not evaluating the entire body content. If suspicious payloads are embedded beyond the inspected portion of a large POST request (for example, > 8 MB), WAF cannot reliably detect them purely through body inspection rules.

Given this constraint, the most effective way to “ensure” proper protection is to implement an oversize handling strategy using AWS WAF rule logic: block oversized requests by default and then explicitly allow oversized requests only from known legitimate sources. Option A accomplishes this by adding a rule that blocks oversize requests (so attackers cannot bypass inspection by sending very large bodies) and a higher-priority allow rule to permit large requests from trusted hosts (for example, specific known partners, internal CIDRs, or authenticated upstream systems). This design reduces the attack surface and provides deterministic behavior for requests that cannot be fully inspected.

Option B is incorrect because Shield Advanced is for DDoS protection and does not extend WAF’s request-body inspection size. Option C is unrelated: Content-Type can influence application parsing, but it will not overcome WAF body-size inspection limitations. Option D is not a practical fit for AWS WAF inspection because WAF evaluates requests at the edge/service layer; it does not natively “call Lambda to rewrite the request body” before WAF evaluates it. Any preprocessing would require a different architectural pattern (such as handling uploads out-of-band), which is beyond the scope and would add operational complexity.

Therefore, A is the correct approach: implement explicit oversized request handling by blocking by default and allowing only vetted large requests.