Is the cloud always cheaper than running my own servers?

Not automatically. It removes upfront costs and lets you match spending to demand, but poorly managed cloud usage can cost more than owned hardware. Cost management is a skill, covered in a later lesson.

Which cloud provider should I learn first?

The concepts transfer, so pick the one your employer or target jobs use, or start with the one with the most learning material for you. After one, the others take far less time.

Cloud Computing Fundamentals: IaaS, PaaS, SaaS, and Deployment Models

Introduction

Cloud computing means renting computing resources, such as servers, storage, databases, and networking, over the internet and paying for what you use instead of buying hardware. This first lesson of the cloud course explains the core ideas and shows how the three big providers name equivalent services, so skills transfer between them.

Prerequisites

No cloud experience needed
Basic understanding of what servers and databases are

Step-by-Step Guide

Step 1: Learn what makes it "cloud"

The cloud is defined by a few properties: you get resources on demand through self-service, you can scale them up and down quickly (elasticity), capacity is pooled and shared among customers, and usage is metered so you pay for what you consume. This turns large upfront hardware purchases into an operating cost that follows demand.

Step 2: Know the service models

Infrastructure as a Service (IaaS) gives you virtual machines, storage, and networks that you configure yourself. Platform as a Service (PaaS) runs your code for you without managing servers, such as managed web app hosting and databases. Software as a Service (SaaS) is a finished application you just use, like email or a CRM. Serverless, or function as a service, is a form of PaaS where code runs only when triggered and you do not manage capacity at all. The higher up you go, the less you manage and the less control you have.

Step 3: Know the deployment models

A public cloud shares provider infrastructure among many customers, which is what AWS, Azure, and Google Cloud offer. A private cloud is dedicated to one organization. A hybrid cloud connects on-premises systems with a public cloud. Multi-cloud means using more than one provider. Most organizations end up hybrid or multi-cloud for regulatory, cost, or historical reasons.

Step 4: Understand regions and availability zones

A region is a geographic area that contains several data centers. Regions are divided into availability zones, which are separate locations with independent power and networking. You choose a region for latency, legal requirements, and cost, and you spread workloads across zones so one failure does not take everything down.

Step 5: Map the equivalent services

Each provider uses different names for similar building blocks. Learning one makes the others much easier. Service names evolve, so confirm current names in each provider's documentation.

Building block      AWS                 Azure                      Google Cloud
------------------  ------------------  -------------------------  ------------------------
Virtual machines    EC2                 Virtual Machines           Compute Engine
Object storage      S3                  Blob Storage               Cloud Storage
Serverless code     Lambda              Azure Functions            Cloud Run functions
Containers (PaaS)   App Runner / ECS    Container Apps             Cloud Run
Managed SQL         RDS                 Azure SQL Database         Cloud SQL
Identity & access   IAM                 Entra ID + Azure RBAC      Cloud IAM
Virtual network     VPC                 Virtual Network            VPC
Monitoring          CloudWatch          Azure Monitor              Cloud Monitoring

FAQs

Is the cloud always cheaper than running my own servers?: Not automatically. It removes upfront costs and lets you match spending to demand, but poorly managed cloud usage can cost more than owned hardware. Cost management is a skill, covered in a later lesson.
Which cloud provider should I learn first?: The concepts transfer, so pick the one your employer or target jobs use, or start with the one with the most learning material for you. After one, the others take far less time.

Summary

Cloud computing is on-demand, elastic, metered infrastructure. Learn the service models (IaaS, PaaS, SaaS, serverless), the deployment models, regions and zones, and the equivalent services across providers, and the rest of cloud learning builds on that.