An on-premises e-commerce web application that stores session state is being migrated to AWS. The application must be fault tolerant, scale natively, and avoid any user-visible interruptions during service outages. Which is the best place to store session state in AWS?

Storing session state in Amazon ElastiCache (Redis or Memcached) is the best solution because it provides a highly available, fault-tolerant, and scalable in-memory data store. This allows multiple application instances to share session data, ensuring that users are not interrupted if an instance fails or scales. ElastiCache is designed for low-latency access, which is crucial for e-commerce applications. Amazon CloudFront is a content delivery network (CDN) and does not store session state. Amazon S3 is object storage and is not suitable for low-latency, frequently accessed session data. Enabling sticky sessions on an Elastic Load Balancer can help, but it ties a user's session to a specific instance, which can lead to data loss or interruptions if that instance fails or is scaled down. ElastiCache offers a more robust and scalable solution for shared session state.