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

The correct answers areA, C, and Ebecause the company needs a fully managed solution forSFTP uploads to Amazon S3, followed byautomatic decryptionandmovement of files to another directorywithminimal operational overhead.AWS Transfer Familyis the best fit because it provides a managed SFTP endpoint directly integrated with Amazon S3. Configuring the S3 bucket as the home directory enables customers to upload files without the company needing to manage its own file transfer servers.

The requirement to avoid separate authentication services and minimize operational work is well served by nativeAWS Transfer Family workflows. A workflow can automatically run post-upload steps on files as they arrive. TheDECRYPTaction is specifically designed to decrypt uploaded encrypted files as part of the managed workflow. After decryption, theCOPYaction can place the processed file into the second directory in the same S3 bucket for downstream processing.

Option B is less appropriate because using S3 events and Lambda adds custom orchestration where a native Transfer Family workflow already handles the need more simply. Option D is incorrect because polling with an external script introduces unnecessary infrastructure and operational overhead. Option F is also incorrect because AWS Batch polling and custom decryption logic is far more complex than a managed file-transfer workflow.

AWS best practices favor managed services and native workflow features to reduce custom code and infrastructure management. Therefore, the best solution is to useAWS Transfer Family for SFTP uploads, along withTransfer Family workflow DECRYPTandCOPYactions to automate the full post-upload process.

AWS Key Management Service (AWS KMS) provides multi-Region keys, allowing the same key to be used across Regions without managing your own hardware or key replication.

Multi-Region keys are fully managed and support attribute-based access control (ABAC) using tags and condition keys.

CloudHSM (Options C and D) requires full key lifecycle management, synchronization, and hardware operations, resulting in significantly higher overhead.

Imported key material (Option B) increases key-management responsibility.

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TheAWS_PROXY integration with Amazon API Gatewayallows the API to invoke a Lambda function synchronously, making it a suitable solution for the custom authorization mechanism and text translation use case.

Synchronous Invocation: The API Gateway REST API with AWS_PROXY integration enables synchronous processing of HTTP requests and responses, which is required for document translation.

Custom Authorization: API Gateway supports custom authorizers for fine-grained access control.

Lambda Function Execution: Although Lambda ' s execution time limit is 15 minutes, this is sufficient for the 6-minute document translation requirement.

Why Other Options Are Not Ideal:

Option B:

Introducing a Lambda function URL to invoke another Lambda function unnecessarily complicates the architecture.Not efficient.

Option C:

Asynchronous invocation cannot guarantee real-time response delivery for document translation tasks.Not suitable.

Option D:

Hosting the API on an EC2 instance increases operational overhead. HTTP PROXY integration does not add significant benefits here.Not cost-effective or efficient.

AWS References:

API Gateway Lambda Proxy Integration:AWS Documentation - Proxy Integration

Custom Authorization in API Gateway:AWS Documentation - Custom Authorization

The application experiences unpredictable traffic spikes, which exceed the provisioned read and write capacity of the DynamoDB table, resulting in throttling errors. This is a classic scenario where on-demand capacity mode is the most appropriate solution.

Option A is correct because DynamoDB on-demand capacity automatically scales to handle sudden increases in traffic without requiring capacity planning. This eliminates throttling during unpredictable spikes and removes the operational burden of managing RCUs and WCUs. On-demand mode is particularly well-suited for workloads with variable or spiky access patterns.

Option B is incorrect because DynamoDB does not support read replicas in the same way as relational databases. Option C reduces cost for predictable workloads but does not prevent throttling if capacity limits are exceeded. Option D increases read cost and does not address capacity constraints.

Therefore, A is the best solution to improve resilience, eliminate throttling errors, and ensure a smooth user experience during traffic surges.

Option A: Importing customer-managed keys into AWS KMS ensures that encryption key material remains under the company’s control.

Option D: S3 Glacier with server-side encryption using customer-provided keys (SSE-C) complies with the need for controlled encryption and provides cost-effective storage for backups.

AWS Key Management Service Importing Keys Documentation,S3 Encryption Documentation

The most cost-effective solution for serving video content with different bitrates is to store multiple versions of each video inAmazon S3. S3 provides scalable and cost-effective storage for largemedia files. Serving the videos from a single Amazon EC2 instance ensures low-latency delivery, and S3 storage helps minimize costs.

Option A (ElastiCache): Caching large video files in memory would be prohibitively expensive and unnecessary.

Option B (Auto Scaling group): Using Auto Scaling groups to serve video is less cost-effective compared to leveraging S3 for static storage.

Option D (Kinesis Video Streams): Kinesis Video Streams is designed for real-time video streaming and is not suitable for storing and serving pre-recorded videos.

AWS References:

Amazon S3 for Media Storage

AWSSecrets Managercan integrate directly with Amazon RDS for automatic and seamless password rotation. Secrets Manager handles the complexity of password management, including generating strong passwords and rotating them at a defined interval (e.g., every 30 days). It also automatically updates the connection information for RDS, minimizing operational overhead.

Option A (Lambda with EventBridge): While possible, this requires custom coding and operational management of Lambda, which introduces additional complexity.

Option B (Manual password change): Using the modify-db-instance command requires manual intervention and is not automated, leading to more operational effort.

Option D (Parameter Store): Systems Manager Parameter Store is less specialized for password management than Secrets Manager and does not have built-in automated rotation for RDS credentials.

AWS References:

AWS Secrets Manager Rotation for RDS

Amazon Aurora MySQL provides:

Continuous, incremental backups to Amazon S3 with point-in-time recovery (PITR), allowing recovery to any point within the retention window (typically up to 35 days). This easily achieves an RPO of less than 5 hours, often down to seconds.

Support for database auditing parameters so audit logs can be retained and managed (for example, in database logs or external log services) to meet the 7-day audit requirement.

Auto scaling (via read replicas, Aurora Serverless v2, or capacity management) to handle variable read/write demand throughout the year with minimal operational overhead.

Why others are less suitable:

A: DynamoDB is NoSQL and does not directly satisfy typical relational database + SQL audit requirements; Streams also only retain 24 hours, not 7 days, and on-demand backups do not inherently give an RPO < 5 hours without frequent scheduling.

B: Amazon Redshift is a data warehouse, not a primary transactional application database.

C: Snapshots every 5 hours give an RPO of up to 5 hours, not less than 5 hours, and rely on discrete snapshot points rather than continuous PITR.

Amazon ElastiCache (Redis OSS) provides an in-memory cache that drastically improves read performance with minimal operational overhead.

It integrates easily with RDS and does not require schema or database changes.

EC2-based caching (Option C) increases management overhead.

DAX (Option D) accelerates DynamoDB only, not RDS.

Moving to DynamoDB (Option A) requires complete application and schema redesign.

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