Let's start with the name. Where did 'cloud' come from?
When the internet was in its infancy, the word 'cloud' was used as a metaphor to describe how complex telephone networks connected with each other. Today, many refer to this complexity as 'THE cloud,' but it's not a single entity, nor does it exist in the sky or one place. So, what exactly is the Cloud?
The concept of the "Cloud" embodies communication and computing where servers, networks, storage, development tools, and applications (apps) are enabled through the internet. Instead of organizations making significant investments to buy equipment, train staff, and provide ongoing maintenance, a cloud service provider handles some, if not all, of these needs.
There are five key characteristics of a cloud computing environment, as defined by the National Institute of Standards and Technology (NIST):
Internet Access
With a public cloud environment, users "plug into" the data and applications via an internet connection, anytime, anywhere.
Measured Service
Cloud is often pay-as-you-go, where you only pay for what you use. Think about how a utility company meters how much water, electricity, or gas is used and charges based on consumption. The Cloud is the same.
On-Demand Self-Service
Services can be requested and provisioned quickly, without the need for manual setup and configuration.
Shared Resource Pooling
Cloud often uses the multi-tenancy model. This means a single application is shared among several users. So, rather than creating a copy of the application for each user, several users or "tenants" can configure the online application to their specific needs.
Rapid Elasticity
Cloud platforms are elastic. An organization can scale its resource usage levels up or down quickly and efficiently as needs change.