Summary
In this chapter, you reviewed some basic but powerful concepts about the cloud and why it is so popular. Mainly the concepts of availability, reliability, and scalability. You also learned about three different types of architecture, each offering different levels of availability. As expected, an architecture that offers higher availability is a more expensive solution that requires more resources.
You also explored the concepts of RPO and RTO, which are helpful ideas for tracking and measuring system availability. Additionally, you analyzed the differences between scaling up and scaling out. And finally, you went over some highly available services in AWS, including Amazon ELBs.
ELBs are especially useful when application traffic is highly variable. They enable you to treat your compute resources like a special computer that can expand and contract depending on demand.
In the next chapter, you will learn some hands-on tricks and tips in AWS.