In this chapter, we will introduce some key design principles and approaches to achieving high availability in your applications deployed on the AWS cloud. As a good practice, you want to ensure that your mission-critical applications are always available to serve your customers. The approaches in this chapter will address availability across the layers of your application architecture including availability aspects of key infrastructural components, ensuring there are no single points of failure. In order to address availability requirements, we will use the AWS infrastructure (Availability Zones and Regions), AWS Foundation Services (EC2 instances, Storage, Security and Access Control, Networking), and the AWS PaaS services (DynamoDB, RDS, CloudFormation, and so on). In addition to availability, we will describe several approaches used for disaster recovery. We will also show you how to implement high availability for our sample...