SAA-C03 Exam Dumps : AWS Certified Solutions Architect - Associate (SAA-C03)

To address the high CPU utilization on the EC2 instance and the degraded performance of Amazon RDS for read requests, the solution involves two key actions: resizing the EC2 instance and leveraging Amazon RDS read replicas.

Resizing the EC2 Instance: The first step is to resize the EC2 instance to a type with more CPU capacity to handle the higher computational demands during peak usage times. This helps to alleviate the immediate pressure on the CPU.

Auto Scaling Group with a Size of 1: Although the application can only run on a single EC2 instance due to its monolithic nature, creating an Auto Scaling group with a minimum and maximum size of 1 ensures that the instance is automatically restarted or replaced in case of failure, maintaining high availability.

RDS Read Replica: Configuring an RDS read replica allows the application to offload read requests to a separate instance, thus reducing the load on the primary RDS instance. This improves the performance of read operations, which were previously bottlenecked due to the high CPU usage on the EC2 instance.

Why Not Other Options?:

Option B: Redirecting all traffic to the RDS read replica is not recommended because replicas are meant for read traffic only, not for write operations. This could lead to data consistency issues.

Option C: Increasing the RDS instance type capacity helps, but it doesn’t address the high CPU usage on the EC2 instance, nor does it provide a solution for scaling reads.

Option D: While resizing both the EC2 and RDS instances increases their capacities, it doesn’t address the specific need to offload read traffic from the primary RDS instance.

AWS References:

Amazon RDS Read Replicas- Explains how to create and use read replicas to offload read traffic from the primary database instance.

Resizing Your EC2 Instance- Guidance on resizing EC2 instances to meet workload demands.

Comprehensive and Detailed 250 to 300 words of Explanation (AWS documentation-based, no links):

The requirements are straightforward: expose the Lambda microservice through an HTTPS endpoint and authenticate calls using IAM. Lambda function URLs are a built-in feature that provides a dedicated HTTPS endpoint for a Lambda function without requiring API Gateway, ALB, or CloudFront. When configured with the authentication type AWS_IAM, the endpoint requires requests to be signed with AWS Signature Version 4 and authorized by IAM policies. This directly satisfies the “must use IAM to authenticate calls” requirement with the least architectural complexity.

Option A can also secure an endpoint with IAM, but it proposes using a Lambda authorizer, which is typically used for custom authorizers (JWT/OAuth/Cognito/external identity). For IAM authentication in API Gateway, you generally use IAM authorization on the method, not an authorizer function. Also, API Gateway REST APIs introduce additional service configuration and per-request costs when a simpler managed option exists that meets the requirements.

Options C and D are not appropriate. Lambda@Edge and CloudFront Functions run at CloudFront edge locations with different programming and deployment models; they are designed for CDN request/response manipulation, not as the primary mechanism to expose a regional Lambda microservice endpoint with IAM authentication. CloudFront Functions in particular is for lightweight JavaScript at the edge and does not provide a native “AWS_IAM authentication type” for invoking an origin Lambda as a microservice endpoint.

Therefore, B is the cleanest and most secure fit: a native HTTPS endpoint backed by Lambda, protected with IAM-based SigV4 authentication.

S3 Object Lock in Compliance Mode prevents objects from being deleted or overwritten for a fixed, specified retention period. Compliance Mode is specifically designed to meet regulatory requirements, ensuring that no user, including the root user, can modify or delete the object during the retention period.

Reference Extract:

" S3 Object Lock in compliance mode protects objects from being deleted or overwritten during the specified retention period, helping meet regulatory retention requirements. "

Source: AWS Certified Solutions Architect – Official Study Guide, S3 Object Lock and Compliance section.