Public cloud providers often have the ability to scale their services indefinitely to provide unlimited computing, storing, and networking functionalities. In this chapter, we will cover basic failure scenarios and how to overcome them by using vertical scaling and the virtual management of resources. We will also look at how to manage persistent configurations and failover by using decoupled resources, such as virtual IPs.

We will introduce EBS as a resilient service by managing the persistent state of our data with high durability, and look at how it can be used as a business continuity model for disaster recovery. We will explain the vertical scaling of an RDS database and will provide you with a deep understanding of how availability is managed and calculated.

The following topics will be covered in this chapter:

• Availability metrics and their associated dependencies
• Implementing vertical scaling with EC2 and RDS
• Image versioning and image life cycles, illustrated with snapshots
• How to bootstrap a web server with scripting
• Provisioning persistent EBS disks and operating them via the CLI
• Performing a stress test to benchmark different instance sizes