2-Tier Auto-scalable Web Application Architecture in 1 AZ

"In computer networking, cloud computing is computing that involves a large number of computers connected through a communication network such as the Internet, similar to utility computing. ...
Network-based services, which appear to be provided by real server hardware, and are in fact served up by virtual hardware, simulated by software running on one or more real machines are often called cloud computing. Such virtual servers do not physically exist and can therefore be moved around and scaled up or down on the fly without affecting the end user, somewhat like a cloud becoming larger or smaller without being a physical object. ...
Typically, the seller has actual energy-consuming servers which host products and services from a remote location, so end-users don't have to; they can simply log on to the network without installing anything. The major models of cloud computing service are known as software as a service, platform as a service, and infrastructure as a service. These cloud services may be offered in a public, private or hybrid network. Google, Amazon,leadsquared.com, Oracle Cloud, Salesforce, Zoho, Access2MyPC, and Microsoft Azure are some well-known cloud vendors." [Cloud computing. Wikipedia]
The AWS architecture diagram example "2-Tier Auto-scalable Web Application Architecture in 1 AZ" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the AWS Architecture Diagrams solution from the Computer and Networks area of ConceptDraw Solution Park.