Amazon Web Services Updated SAP-C02 Exam Questions and Answers by luan

For a development environment that requires frequent resource recreation and connectivity to applications hosted in a shared services account, the most efficient solution involves using AWS Resource Access Manager (RAM) and the transit gateway in the shared services account. By turning on automatic acceptance for the transit gateway in the shared services account and sharing it with the development account through AWS RAM, the development team can easily recreate their connection as needed without manual intervention. This setup allows for scalable, flexible connectivity between accounts while minimizing operational overhead and ensuring consistent access to shared services.

AWS Documentation on AWS Resource Access Manager and Transit Gateway provides guidance on sharing network resources across AWS accounts and enabling automatic acceptance for transit gateway attachments. This approach is also supported by AWS best practices for multi-account strategies using AWS Organizations and network architecture.

S3 Event Notifications is a feature that allows users to receive notifications when certain events happen in an S3 bucket, such as object creation or deletion1. Users can configure S3 Event Notifications to invoke an AWS Lambda function when a user stores an image in the bucket. Lambda is a serverless compute service that runs code in response to events and automatically manages the underlying compute resources2. The Lambda function can resize the image in place and store the original file in the same S3 bucket. This way, the solution can handle significant variance in demand and be reliable at enterprise scale. Thesolution can also rerun processing jobs in the event of failure by using the retry and dead-letter queue features of Lambda2.

S3 Lifecycle is a feature that allows users to manage their objects so that they are stored cost-effectively throughout their lifecycle3. Users can create an S3 Lifecycle policy to move all stored images to S3 Standard-Infrequent Access (S3 Standard-IA) after 6 months. S3 Standard-IA is a storage class designed for data that is accessed less frequently, but requires rapid access when needed4. It offers a lower storage cost than S3 Standard, but charges a retrieval fee. Therefore, moving the images to S3 Standard-IA after 6 months can reduce the storage cost for the solution.

Option A is incorrect because using AWS Step Functions to process the S3 event that occurs when a user stores an image is not necessary or cost-effective. AWS Step Functions is a service that lets users coordinate multiple AWS services into serverless workflows. However, for this use case, a single Lambda function can handle the image resizing task without needing Step Functions.

Option B is incorrect because using Amazon EventBridge to process the S3 event that occurs when a user uploads an image is not necessary or cost-effective. Amazon EventBridge is a serverless event bus service that makes it easy to connect applications with data from a variety of sources. However, for this use case, S3 Event Notifications can directly invoke the Lambda function without needing EventBridge.

Option D is incorrect because using Amazon Simple Queue Service (Amazon SQS) to process the S3 event that occurs when a user stores an image is not necessary or cost-effective. Amazon SQS is a fully managed message queuing service that enables users to decouple and scale microservices, distributed systems, and serverless applications. However, for this use case, S3 Event Notifications can directly invoke the Lambda function without needing SQS. Moreover, storing the resized file in an S3 bucket that uses S3 Standard-IA will incur a retrieval fee every time the file is accessed, which may not be cost-effective for frequently accessed files.

The workload is a real-time leaderboard that needs extremely low latency: microsecond reads and single-digit millisecond writes. It also needs rapid failover (accepting writes in less than a minute after a primary node failure) and minimal operational overhead. Additionally, the data must be durable enough to persist and be used later for analytics through a data pipeline.

Amazon MemoryDB for Redis is a Redis-compatible, durable, in-memory database service designed for microsecond read latency and low-millisecond write latency while also providing durability through a distributed transaction log. MemoryDB is designed to be a primary database rather than a cache and supports Multi-AZ configurations with fast failover. These characteristics match the leaderboard’s latency requirements and the availability requirement to resume writes quickly after a failure. Because MemoryDB is fully managed, it has less operational overhead than running Redis on EC2.

Option C is the best choice because MemoryDB provides Redis compatibility, in-memory performance, Multi-AZ high availability, and durability that supports data persistence for downstream processing. The durability aspect is especially important for feeding analytics pipelines, because the data is not only cached but is retained as a database record.

Option A is not the best choice because Amazon ElastiCache for Redis is primarily used as a cache. While it can be configured for replication and can achieve low latency, it is not positioned as a durable primary data store in the same way as MemoryDB for Redis. For requirements that explicitly combine extremely low latency with persistence and database-like durability, MemoryDB is the more appropriate managed service with lower operational overhead than building custom durability mechanisms.

Option B is not suitable because Amazon RDS for MySQL typically cannot meet microsecond read latency, and write latencies are usually higher than single-digit milliseconds for non-trivial workloads. Also, read replicas do not provide multi-writer capability and do not ensure sub-minute write availability in all failure scenarios without additional architecture and failover handling.

Option D has the highest operational overhead because it requires the company to operate Redis on EC2: instance management, patching, scaling, replication, failover automation, monitoring, and backup/restore processes. This does not meet the requirement for the least operational overhead compared to fully managed services.

Therefore, an Amazon MemoryDB cluster in Multi-AZ mode provides the required ultra-low latency, rapid failover for write availability, durability for persistence, and least operational overhead.