Dive into AWS Cloud Fundamentals: Your First Concrete Step Today

The best way to learn AWS Cloud Fundamentals is by doing. This article gives you a head start with practical excerpts from a 33-lesson course — enough to get your first result today.

Security Groups, Elastic IP and custom AMIs

Chapter 02 • Lesson 02 • Duration: 45 min

1. Security Groups — the AWS firewall

A Security Group (SG) is a stateful firewall that controls inbound (inbound) and outbound (outbound) traffic of an EC2 instance.

Key characteristics

Example: Security Group for a web server

Security Groups best practices

Security Group referencing another SG

SG-db inbound :
   Port 3306 (MySQL) | Source : sg-app | "App servers only"

2. Ephemeral public IP vs Elastic IP

Standard public IP (auto-assigned)

Elastic IP (EIP)

When to use an EIP?

Hands-on: assign an Elastic IP

1. EC2 Console → left menu → "Elastic IPs"
2. "Allocate Elastic IP address"
3. Network Border Group : your region
4. Allocate → a new IP is created
5. Select the IP → Actions → "Associate Elastic IP address"
6. Instance : select your EC2
7. Associate

→ Your instance now has a static IP

3. User Data — automate boot

User Data is a script (bash or PowerShell) that runs at the very first boot of the instance. Ideal for automating initial setup.

Example: install Nginx automatically at launch

#!/bin/bash
# User Data for Ubuntu

apt update -y
apt install -y nginx
systemctl enable nginx
systemctl start nginx

# Custom home page
cat > /var/www/html/index.nginx-debian.html <<EOF
<h1>Auto-deployed AWS server</h1>
<p>Hostname : $(hostname)</p>
<p>Date : $(date)</p>
EOF

Where to paste the User Data?

EC2 Console → Launch instance →
"Advanced details" section (at the very bottom) →
"User data" → paste the script

sudo cat /var/log/cloud-init-output.log

4. Custom AMI — "reference ghost"

What is Cloud Computing? IaaS, PaaS, SaaS explained

Chapter 01 • Lesson 01 • Duration: 40 min

1. Official Cloud definition (NIST)

The NIST (National Institute of Standards and Technology, USA) defines Cloud Computing as:

5 essential characteristics

2. Before the Cloud: the "On-Premises" era

Before 2006 (AWS launch), to host a web application you had to:

Total: 6-12 months and 100 000+ € to get started.

3. The 3 service models: IaaS, PaaS, SaaS

The famous pizza analogy 🍕

IaaS — Infrastructure as a Service

PaaS — Platform as a Service

SaaS — Software as a Service

4. IaaS/PaaS/SaaS responsibility matrix

5. Beyond: FaaS, CaaS, DBaaS

⚡ FaaS — Function as a Service

You write a function (e.g. in Python). It runs on demand. You pay per millisecond.

AWS Lambda is the standard.

Launch your first EC2 instance (step by step)

Chapter 02 • Lesson 01 • Duration: 50 min

1. What is EC2?

EC2 = Elastic Compute Cloud. It is AWS's flagship service launched in 2006. It lets you rent virtual machines (Linux or Windows) by the minute.

⚡ Characteristics

🧱 Instance components

2. AMI — Amazon Machine Image

An AMI is the equivalent of a "bootable ISO image" prepared by AWS or the community. It contains the OS, bootloader, and sometimes pre-installed software.

3. EC2 instance types

The instance type defines CPU, RAM, network, and disk. Format: family.size (e.g. t3.micro).

Main families

Available sizes (smallest to largest)

nano → micro → small → medium → large → xlarge → 2xlarge → 4xlarge → 8xlarge → 16xlarge → 32xlarge

Free Tier: t2.micro / t3.micro

4. Hands-on: launch a t3.micro Ubuntu instance

Step 4.1 — Start the wizard

1. AWS Console → search bar → "EC2"
2. Check region top right (e.g. eu-west-3 Paris)
3. Left menu → "Instances" → "Launch instances"

Step 4.2 — Configuration

Step 4.3 — .pem file permissions (Linux/Mac)

mv ~/Downloads/aws-course51.pem ~/.ssh/
chmod 400 ~/.ssh/aws-course51.pem

Without chmod 400, SSH will refuse to connect with "permissions too open" error.

FAQ

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