The AWS Certified Solutions Architect - Associate (SAA-C03) (AWS-Solution-Architect-Associate)

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.

Comprehensive and Detailed Step-by-Step Explanation:

To accurately charge customers based on their monthly data download usage, the following solution is recommended:

Structured Logging Configuration:

Action:Ensure that the AWS Transfer for SFTP server is configured to log user activity, including details about file downloads, to Amazon S3 in a structured format.

Implementation:Utilize AWS Transfer Family ' s structured logging feature to capture detailed information about user sessions, including actions performed and data transferred.

docs.aws.amazon.com

Justification:Structured logs provide comprehensive data necessary for analyzing customer-specific download activities.

Data Analysis with Amazon Athena:

Action:Use Amazon Athena to run SQL queries on the structured log data stored in the S3 bucket to calculate the amount of data each customer has downloaded.

Implementation:

a.Define a Schema:Create a table in Athena that maps to the structure of your log files. This involves specifying the format of the logs and the location in S3.

b.Query Data:Write SQL queries to sum the total bytes downloaded by each customer over the billing period. This can be achieved by filtering logs based on user identifiers and summing the data transfer amounts.

Justification:Athena allows for efficient querying

For improving availability and performance of the hybrid application, the following solutions are optimal:

AWS Global Accelerator (Option A): Global Accelerator provides high availability and improves performance by using the AWS global network to route user traffic to the nearest healthy endpoint (across AWS Regions). By adding the Network Load Balancers as endpoints, Global Accelerator ensures that traffic is routed efficiently to the closest endpoint, improving both availability and performance.

Network Load Balancer (Option D): Thestateful TCP-based workloadhosted on Amazon EC2 instances and thestateless UDP-based workloadhosted on-premises are best served by Network Load Balancers (NLBs). NLBs are designed to handle TCP and UDP traffic with ultra-low latency and can route traffic to both EC2 and on-premises endpoints.

Option B (CloudFront and Route 53): CloudFront is better suited for HTTP/HTTPS workloads, not for TCP/UDP-based applications.

Option C (ALB): Application Load Balancers do not support the stateless UDP-based workload, making NLBs the better choice for both TCP and UDP.

AWS References:

AWS Global Accelerator

Network Load Balancer

AWS Secrets Manager is a fully managed service specifically designed to securely store and automatically rotate database credentials, API keys, and other secrets. Secrets Manager provides built-in integration with Amazon RDS for automatic credential rotation on a configurable schedule without requiring downtime. It also manages the secure distribution of the credentials to authorized services, such as your web servers, using IAM policies. Manual solutions (S3, files, cron jobs) do not provide the same level of automation, audit, or security.

Reference Extract from AWS Documentation / Study Guide:

" AWS Secrets Manager enables you to rotate, manage, and retrieve database credentials securely. It supports automatic rotation of secrets for supported AWS databases without requiring application downtime. "

Source: AWS Certified Solutions Architect – Official Study Guide, Security and Secrets Management section.

Amazon RDS for MySQL Reserved Instances provide significant savings over on-demand pricing when you plan to run the database for long periods. This is the most cost-effective option for non-production, long-running managed MySQL workloads.

Reference Extract:

" Reserved Instances provide a significant discount compared to On-Demand pricing and are recommended for steady-state workloads that run for an extended period. "

Source: AWS Certified Solutions Architect – Official Study Guide, RDS Cost Optimization section.

AWS Backup is a fully managed backup service that can create backup plans for EC2 instances, including both instance configurations and attached EBS volumes, with scheduled and cross-Region copy capabilities. By adding the EC2 instances to the resource assignment in the backup plan, AWS Backup automatically backs up all configurations and attached EBS volumes, and can copy backups to a secondary Region for disaster recovery, providing the highest operational efficiency with the least manual effort.

AWS Documentation Extract:

“AWS Backup provides fully managed backup for EC2 instances and attached EBS volumes, with scheduling, retention, and cross-Region copy built in. By adding the EC2 instance as a resource, the backup includes both configuration and attached volumes.”

(Source: AWS Backup documentation)

A, D: Custom Lambda scripts increase operational overhead and are not as integrated or robust as AWS Backup.

C: Assigning only EBS volumes does not include the EC2 instance configuration, which is needed for full recovery.

AWS CloudTrail Lakeis a fully managed service that allows the collection, storage, and querying ofCloudTrail eventsfor both AWS and non-AWS services. CloudTrail Lake can be customized to collect logs from various sources, ensuring a centralized audit solution. It also supports long-term storage, so logs can be retained for 7 years, meeting the compliance requirement.

Option A (Data Lake): Setting up a data lake in S3 introduces unnecessary operational complexity compared to CloudTrail Lake.

Option C (Ingest non-AWS services into CloudTrail): CloudTrail Lake is better suited for this task with less operational overhead.

Option D (CloudWatch Logs): While CloudWatch can store logs, CloudTrail Lake is specifically designed for API auditing and storage.

AWS References:

AWS CloudTrail Lake

AWS documentation states that Amazon Macie is the managed service designed to automatically identify and classify sensitive data stored in Amazon S3 , including PII and healthcare-related identifiers.

Storing logs in Amazon S3 provides scalable, durable storage, and Amazon Athena can directly query JSON data stored in S3 using SQL.

Amazon Inspector (Option D) is for vulnerability scanning and does not identify sensitive data. DynamoDB with KMS (Option C) cannot detect sensitive information. EBS (Option B) requires custom tooling and does not support serverless SQL querying.

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AWS KMS automatic key rotationis the simplest and most operationally efficient solution. Enabling automatic key rotation ensures that KMS automatically generates new key material for the key every year without requiring manual intervention.

Option B:Configuring alerts to rotate keys introduces operational overhead as the actual rotation must still be managed manually.

Option C:Scheduling a Lambda function to rotate keys adds unnecessary complexity compared to enabling automatic key rotation.

Option D:Using a CloudFormation stack to run a Lambda function for key rotation increases operational overhead and complexity unnecessarily.

AWS Documentation References:

AWS KMS Key Rotation

Using Customer-Managed Keys with Amazon RDS