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OOTW / Chapter I - Foundation / 02. Virtualization / 03. Cloud Infrastructure

Cloud Infrastructure

Modern organizations increasingly rely on cloud resources.

Even the exam for this course is deployed on the cloud.

Traditionally, organizations purchased and maintained their own hardware.

Company
    ↓
Buys Server
    ↓
Installs Operating System
    ↓
Runs Applications

This model is often referred to as on-premises infrastructure.

While it provides complete control, it also introduces significant costs:

  • Hardware purchases
  • Maintenance
  • Power
  • Cooling
  • Physical security
  • Hardware replacement

Cloud providers solve this problem by allowing organizations to rent infrastructure instead.

What Is The Cloud?

The cloud is simply somebody else's infrastructure that you rent and access over the Internet.

A cloud provider owns:

  • Datacenters
  • Physical servers
  • Networking equipment
  • Storage systems

Customers rent resources from those datacenters.

Examples include:

  • Amazon Web Services (AWS)
  • Microsoft Azure
  • Google Cloud Platform

Conceptually:

Your Company
    ↓
Cloud Provider
    ↓
Datacenter
    ↓
Servers

Why Organizations Use The Cloud

The biggest advantage is flexibility.

Instead of purchasing hardware:

Need New Server
      ↓
Wait Weeks
      ↓
Install Hardware
      ↓
Configure

organizations can simply create one:

Need New Server
      ↓
Click Button
      ↓
Server Ready

Often within minutes.

Cloud Service Models

Infrastructure as a Service (IaaS)

The provider gives you infrastructure.

You manage:

  • Operating System
  • Applications
  • Services

The provider manages:

  • Hardware
  • Storage
  • Networking

Example:

Azure VM
AWS EC2
DigitalOcean Droplet

You receive a server and manage everything inside it.

Platform as a Service (PaaS)

The provider manages more components.

You focus primarily on the application.

Example:

Azure App Service
AWS Elastic Beanstalk

You deploy code.

The platform handles much of the infrastructure.

Software as a Service (SaaS)

The provider manages almost everything.

Users simply consume the service.

Examples:

Microsoft 365
Google Workspace
Salesforce

Virtual Private Servers (VPS)

A VPS is one of the simplest cloud resources.

Conceptually:

Physical Server
        ↓
Hypervisor
        ↓
VM 1
VM 2
VM 3
VM 4

A VPS is simply one of those virtual machines.

Popular VPS providers:

  • DigitalOcean
  • Linode
  • Vultr
  • Hetzner

A VPS usually provides:

  • Public IP address
  • Operating System
  • Storage
  • CPU
  • RAM

You administer it exactly like any other Linux or Windows server.

Common Cloud Resources

Cloud providers expose many building blocks.

Virtual Machines

Traditional servers.

Examples:

Azure VM
AWS EC2

Storage

Used for files and data.

Examples:

Backups
Documents
Images
Logs

Databases

Managed database services.

Examples:

MySQL
PostgreSQL
Microsoft SQL Server

Networking

Cloud providers allow creation of:

  • Virtual networks
  • Subnets
  • Firewalls
  • Load balancers
  • VPNs

Much like a traditional datacenter.

Containers

Containers can also be hosted in cloud environments.

Cloud
   ↓
Container Platform
   ↓
Containers

This is extremely common in modern organizations.

Identity In The Cloud

One of the most important concepts in modern cloud environments is identity.

Instead of:

Server
    ↓
Administrator

we often see:

Identity
     ↓
Permissions
     ↓
Resources

The ability to control identities is often more valuable than controlling individual systems.

This becomes especially important when studying:

  • Azure
  • AWS
  • Entra ID
  • IAM

Cloud Security Mindset

When approaching a cloud environment, operators generally think about four areas:

Compute

Virtual machines and containers.

Storage

Files, backups, databases and secrets.

Networking

Connectivity between resources.

Identity

Users, groups, roles and permissions.

Identity is frequently the most important component.

In many modern environments, compromising the right identity is more valuable than compromising a single server.