Cloud Computing & AWS Overview

1. How a website works, and what a server is made of

Before any AWS service makes sense, the deck starts from the plumbing. A client (your laptop, your phone) has an IP address. A server has an IP address too. The client sends a request over the network, the server answers. The analogy the slides use is post mail: you write an address on an envelope and the postal system figures out the route.

A server is composed of:

Compute: CPU
Memory: RAM
Storage: data
Database: storing data in a structured way
Network: routers, switches, DNS servers

Two networking terms worth pinning down, because they come back later in the VPC material:

Network — cables, routers and servers connected to one another.
Router — a networking device that forwards data packets between computer networks. Routers know where to send your packets on the internet.
Switch — takes a packet and sends it to the correct server or client inside your own network.

2. Problems with the traditional IT approach

The slides list what you are actually signing up for when you own the hardware:

Pay rent for the data center.
Pay for power supply, cooling and maintenance.
Adding and replacing hardware takes time.
Scaling is limited.
Hire a 24/7 team to monitor the infrastructure.
Deal with disasters — earthquake, power shutdown, fire.

The question the deck poses: can we externalize all this? That is the cloud.

3. What is cloud computing?

Cloud computing is the on-demand delivery of compute power, database storage, applications and other IT resources, through a cloud services platform, with pay-as-you-go pricing.

What that buys you concretely:

You provision exactly the right type and size of computing resources you need.
You can access as many resources as you need, almost instantly.
It is a simple way to reach servers, storage, databases and a set of application services.
AWS owns and maintains the network-connected hardware required for these application services, while you provision and use what you need via a web application.

4. The deployment models of the cloud

Model	What it means	Why you would pick it
Private Cloud	Cloud services used by a single organization, not exposed to the public	Complete control, security for sensitive applications, meeting specific business needs
Public Cloud	Cloud resources owned and operated by a third-party cloud service provider, delivered over the Internet	The six advantages of cloud computing (below)
Hybrid Cloud	Keep some servers on premises and extend some capabilities to the cloud	Control over sensitive assets in your private infrastructure, plus the flexibility and cost-effectiveness of the public cloud

5. The five characteristics of cloud computing

These five are a classic list-recall question.

On-demand self service — users provision resources and use them without human interaction from the service provider.
Broad network access — resources are available over the network and can be accessed by diverse client platforms.
Multi-tenancy and resource pooling — multiple customers share the same infrastructure and applications with security and privacy; multiple customers are serviced from the same physical resources.
Rapid elasticity and scalability — automatically and quickly acquire and dispose of resources when needed, scaling based on demand.
Measured service — usage is measured, and users pay correctly for what they have used.

6. The six advantages of cloud computing

Trade capital expense (CAPEX) for operational expense (OPEX) — pay on-demand, don’t own hardware; reduced Total Cost of Ownership (TCO) and operational expense.
Benefit from massive economies of scale — prices are reduced because AWS is more efficient at large scale.
Stop guessing capacity — scale based on actual measured usage.
Increase speed and agility.
Stop spending money running and maintaining data centers.
Go global in minutes — leverage the AWS global infrastructure.

Problems solved by the cloud

The deck frames the same benefits as problems solved:

Flexibility — change resource types when needed.
Cost-effectiveness — pay as you go, for what you use.
Scalability — accommodate larger loads by making hardware stronger or adding additional nodes.
Elasticity — the ability to scale out and scale in when needed.
High availability and fault tolerance — build across data centers.
Agility — rapidly develop, test and launch software applications.

7. Types of cloud computing: IaaS, PaaS, SaaS

Infrastructure as a Service (IaaS) — provides the building blocks for cloud IT: networking, computers, data storage space. Highest level of flexibility, and an easy parallel with traditional on-premises IT.
Platform as a Service (PaaS) — removes the need for your organization to manage the underlying infrastructure; you focus on deploying and managing your applications.
Software as a Service (SaaS) — a completed product that is run and managed by the service provider.

The stack the slides draw runs: Applications · Data · Runtime · Middleware · O/S · Virtualization · Servers · Storage · Networking. On on-premises you manage all nine layers. On IaaS the provider takes virtualization and below. On PaaS the provider also takes the O/S, middleware and runtime. On SaaS the provider manages everything.

Type	On AWS	Elsewhere
IaaS	Amazon EC2	GCP, Azure, Rackspace, Digital Ocean, Linode
PaaS	Elastic Beanstalk	Heroku, Google App Engine (GCP), Windows Azure (Microsoft)
SaaS	Many AWS services, e.g. Rekognition for Machine Learning	Google Apps (Gmail), Dropbox, Zoom

8. Pricing of the cloud — the three fundamentals

AWS has three pricing fundamentals, all following the pay-as-you-go model:

Compute — pay for compute time.
Storage — pay for data stored in the cloud.
Data transfer OUT of the cloud — data transfer IN is free.

9. AWS Cloud history and numbers

2002 — internally launched.
2003 — Amazon realizes its infrastructure is one of its core strengths; the idea goes to market.
2004 — launched publicly with SQS.
2006 — re-launched publicly with SQS, S3 and EC2.
2007 — launched in Europe.

Number facts from the deck:

In 2023, AWS had $90 billion in annual revenue.
AWS accounted for 31% of the market in Q1 2024 (Microsoft second with 25%).
Pioneer and leader of the cloud market for the 13th consecutive year (Gartner Magic Quadrant).
Over 1,000,000 active users.

Use cases

AWS enables you to build sophisticated, scalable applications across a diverse set of industries: Enterprise IT, Backup & Storage, Big Data analytics, website hosting, Mobile & Social Apps, and Gaming.

10. AWS Global Infrastructure

The global infrastructure has four pieces:

AWS Regions
AWS Availability Zones
AWS Data Centers
AWS Edge Locations / Points of Presence

Regions

AWS has Regions all around the world, named things like us-east-1 or eu-west-3. A Region is a cluster of data centers, and most AWS services are Region-scoped.

How to choose a Region — four criteria:

Compliance with data governance and legal requirements — data never leaves a Region without your explicit permission.
Proximity to customers — reduced latency.
Available services within a Region — new services and new features aren’t available in every Region.
Pricing — pricing varies Region to Region and is transparent on the service pricing page.

Availability Zones

Each Region has many Availability Zones — usually 3, minimum 3, maximum 6. For Sydney (ap-southeast-2) they are ap-southeast-2a, ap-southeast-2b, ap-southeast-2c.
Each Availability Zone (AZ) is one or more discrete data centers with redundant power, networking and connectivity.
They are separate from each other, so they are isolated from disasters.
They are connected with high-bandwidth, ultra-low-latency networking.

Points of Presence (Edge Locations)

Amazon has 400+ Points of Presence (400+ Edge Locations and 10+ Regional Caches) in 90+ cities across 40+ countries. Content is delivered to end users with lower latency.

Global vs Region-scoped services

Scope	Services
Global	Identity and Access Management (IAM), Route 53 (DNS), CloudFront (CDN), WAF (Web Application Firewall)
Region-scoped	Amazon EC2 (IaaS), Elastic Beanstalk (PaaS), Lambda (FaaS), Rekognition (SaaS)

11. The Shared Responsibility Model

The model splits the world in two:

AWS = responsibility for the security OF the cloud.
Customer = responsibility for the security IN the cloud.

Each later chapter revisits this split for its own service — EC2, EC2 storage and so on — so it is worth getting the sentence exactly right now.

12. AWS Acceptable Use Policy

The AWS Acceptable Use Policy governs what you may run on AWS. The four prohibitions:

No illegal, harmful, or offensive use or content.
No security violations.
No network abuse.
No e-mail or other message abuse.

Quick recap

Concept	What to remember for the exam
Cloud computing	On-demand delivery of compute, storage, applications and other IT resources with pay-as-you-go pricing
Deployment models	Private (single organization) · Public (third-party provider over the Internet) · Hybrid (some on premises, some in the cloud)
Five characteristics	On-demand self service · Broad network access · Multi-tenancy and resource pooling · Rapid elasticity and scalability · Measured service
Six advantages	CAPEX → OPEX · economies of scale · stop guessing capacity · speed and agility · stop running data centers · go global in minutes
IaaS / PaaS / SaaS	EC2 / Elastic Beanstalk / Rekognition — flexibility decreases, managed-for-you increases
Pricing fundamentals	Compute, Storage, Data transfer OUT — data transfer IN is free
Region	A cluster of data centers; most services are Region-scoped; choose on compliance, latency, service availability and price
Availability Zone	One or more discrete data centers with redundant power, networking and connectivity; usually 3 per Region (min 3, max 6)
Edge Locations	400+ Points of Presence in 90+ cities across 40+ countries, for lower-latency content delivery
Global services	IAM, Route 53, CloudFront, WAF
Shared Responsibility	AWS secures the cloud; the customer secures what they put in it
Acceptable Use Policy	No illegal/harmful/offensive content, no security violations, no network abuse, no message abuse