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

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.

The requirements include:

Scalability: The solution must scale as video files are uploaded.

Long-running tasks: Processing tasks can take up to 30 minutes. AWS Lambda has a maximum execution time of 15 minutes, which rules out options that involve Lambda performing all the processing.

Serverless and event-driven architecture: Ensures cost-effectiveness and high availability.

Analysis of Options:

Option A:

AWS Lambda has a 15-minute timeout, which cannot support tasks that take up to 30 minutes.

EventBridge Scheduler is unnecessary for monitoring files when native event notifications are available.Not a valid choice.

Option B:

AWS Step Functions and AWS Fargate can handle long-running processes, but Amazon EFS is not the ideal storage for uploaded video files in a serverless architecture.

Processing tasks triggered by EFS events are not a common pattern and may introduce complexities.Not the best practice.

Option C:

Amazon S3 is used for storing uploaded files, which integrates natively with event-driven services like EventBridge and Step Functions.

Amazon S3 event notifications trigger a Step Functions workflow, which can orchestrate Fargate tasks to process large video files, meeting the scalability and execution time requirements.Correct choice.

Option D:

Similar to Option A, AWS Lambda cannot handle long-running processes due to its 15-minute timeout.

Invoking Lambda for processing directly is not feasible for tasks that take up to 30 minutes.Not a valid choice.

AWS References:

Amazon S3 Event Notifications:AWS Documentation - S3 Event Notifications

AWS Step Functions:AWS Documentation - Step Functions

AWS Fargate:AWS Documentation - Fargate

Comparison of Storage Services:AWS Storage Options

By leveragingAmazon S3,Step Functions, andFargate, this solution provides a scalable, efficient, and serverless approach to handling video processing tasks.

Amazon S3 presigned URLs are the most secure fit because they providetime-limited access to specific objectswithout requiring the external vendor to have AWS credentials or direct bucket permissions. AWS documentation states that presigned URLs grant temporary access to private S3 objects and can be used for downloads through a browser or program. This is stronger than creating an IAM user or sharing temporary keys because those methods still expose AWS credentials to a third party. A bucket policy based only on source IP is broader and less precise than object-level, time-bounded access. Presigned URLs let the company control exactlywhich objectcan be downloaded andfor how long, which is exactly what the scenario requires. (AWS Documentation)

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For cross-account access, the standard AWS pattern is to create an IAM role in the resource-owning account (the company’s account) and configure the trust policy to allow the external vendor account to assume that role.

Option D correctly follows this model. The company creates an IAM role with the necessary CloudWatch Logs permissions and configures the trust policy to trust the vendor’s IAM role ARN. The vendor then assumes this role to access logs securely.

The other options misconfigure trust relationships or place permissions in the wrong account, breaking the cross-account access model. Therefore, D is the correct solution.