What Is Cloud Computing?

Introduction

When you stream a film, save photos online or use webmail, your data lives on powerful computers in large buildings called data centres. You do not own or look after those computers. You use them over the internet. That is the idea behind cloud computing.

The simple explanation

Cloud computing means renting computing power, storage and software over the internet instead of owning and running it yourself.

It is like electricity. You do not build a power station. You plug in and pay for what you use.

Why people use it

• Pay as you go: no big upfront cost for hardware.
• Scale up and down: add more power for a busy day, then reduce it.
• Speed: a new server can be ready in minutes, not weeks.
• Reach: serve users around the world from nearby locations.
• Less upkeep: the provider handles buildings, power, cooling and hardware repairs.

NIST, a United States standards body, describes five essential traits: on-demand self-service, broad network access, resource pooling, rapid elasticity, and measured service (you are billed for what you use).

Types of cloud

• Public cloud: shared services from a provider such as Amazon Web Services, Microsoft Azure or Google Cloud.
• Private cloud: cloud technology used by only one organisation.
• Hybrid cloud: a mix of public and private.

Is the cloud always better?

Not always. Costs can grow if you are not careful, and you depend on the provider and your internet connection. Some work needs data to stay in certain countries. The next lessons help you judge.

Try it yourself

List five services you use that run in the cloud, such as email, photos, video, maps and chat. For one, think about what would happen if it was unavailable for a day.

Summary

• The cloud means renting computing resources over the internet.
• Benefits include pay-as-you-go pricing, scaling and speed.
• Public, private and hybrid are the common deployment models.