Amazon Elastic Load Balancing is used to spread load and introduce fault tolerance by
distributing connections across multiple identically configured back-end EC2
instances
Amazon DynamoDB is fault tolerant; however, it is not something you add to an
architecture to introduce fault tolerance to the application stack
Amazon CloudFront is a content delivery network that is used for caching content and
serving it to web-based users quickly
Amazon ElastiCache is an in-memory database cache and is used to introduce improved
performance rather than fault tolerance