Cloud Overview | Learn IT Fundamentals with Teacher Pochi

Key points

The cloud is a mechanism for using a provider's computing resources over a network, without owning your own servers.
It's categorized into "IaaS," "PaaS," and "SaaS" depending on how much is provided.
Compared to "on-premises," where a company owns its own servers, the cloud's defining feature is lower upfront cost and operational burden.

On-premises vs. the cloud

Traditionally, "on-premises" — where a company buys its own servers and runs them in its own equipment room (data center) — was the mainstream approach. With the cloud, a cloud provider owns that equipment instead, and users rent only as much as they need over a network.

On-premises
Company owns its own servers

versus

Cloud
Rented from a provider

🔑 Everyday exampleIt's similar to the difference between owning a home (on-premises — you buy it and manage it yourself) and renting an apartment (the cloud — you rent only what you need and leave the management to the landlord).

The advantages of the cloud

Using the cloud eliminates the upfront investment of buying and installing servers, letting you start using exactly what you need right away. It also makes it easy to "scale" — adding resources when traffic increases.

Lower upfront costNo need to purchase servers

Get started quicklyUsable within minutes to hours of signing up

Flexible scalingAdjust resources up or down with traffic

The differences between IaaS, PaaS, and SaaS

Cloud services are broadly divided into three categories based on how much the provider prepares for you.

IaaS Only the foundation, like servers and networking The user builds everything from the OS up

PaaS Provides the OS and runtime environment The user only builds the app

SaaS A fully finished application The user just uses it as-is

The SaaS covered in the "Solution Selection" category is positioned as one of these cloud delivery models.

Understanding IaaS, PaaS, and SaaS with an everyday example

🔑 Everyday exampleThinking of it as making pizza makes this easier to picture. IaaS is like "only the kitchen and ingredients are provided, and you do everything from making the dough yourself." PaaS is like "the dough and oven are ready, and you just add toppings and bake." SaaS is like "a finished pizza simply gets delivered to you." The more that's already provided, the less the user has to do.

Major cloud providers

Here are some of the major cloud providers used widely around the world. Even just knowing the names makes it easier to follow along in on-the-job conversations.

AWS
(Amazon)

Azure
(Microsoft)

GCP
(Google)

Summary

The cloud is a mechanism for renting only the resources you need, like servers, from a provider instead of owning them yourself. Understanding the differences in scope between IaaS, PaaS, and SaaS lets you quickly grasp "how much is already provided, and where your own team's work begins" whenever you hear about a project or tool.