AWS Introduction

Last year Rohan's college in Pune put its exam results on a single office server. At 10 a.m. thousands of students opened the page at once and the server stopped responding. A cloud platform such as Amazon Web Services (AWS) solves this kind of problem: instead of buying one machine and hoping it is big enough, you rent exactly the computing power you need, for as long as you need it, and give it back when the rush is over.

In this lesson you will learn what AWS is, what you can build with it, the four ways you control it, and a few words you will meet in every later lesson.

What is AWS?

Amazon Web Services is Amazon's cloud computing platform. It started offering services to the public in 2006 with Amazon S3 (file storage) and Amazon EC2 (virtual servers), and today it offers more than 200 services: servers, storage, databases, networking, analytics, machine learning and much more.

Cloud computing means using computing resources over the internet from a provider's data centres, and paying only for what you use. You do not buy hardware, wait for delivery or visit a server room. You ask for a resource through a web page or a command, and it is ready in seconds or minutes.

Each service is a building block. Real applications combine several of them:

Four ways to control AWS

Every action in AWS, from creating a server to deleting a file, is a request to an API (application programming interface): a web address that accepts a request and returns a reply in JSON. There are four common ways to send those requests:

1. AWS Management Console: the website at console.aws.amazon.com. Good for learning and exploring.
2. AWS CLI: the aws command in a terminal. Good for repeatable tasks and scripts.
3. SDKs: libraries for programming languages, such as boto3 for Python. Good for applications.
4. Infrastructure as code: template files (CloudFormation, CDK, Terraform) that describe everything you need. Good for real projects.

Here is the same question, "which storage buckets do I have?", asked with the CLI:

aws s3 ls

2026-10-12 09:41:07 priya-notes-2026
2026-10-28 18:02:55 rohtak-shop-invoices

And with Python, using the boto3 SDK:

import boto3

s3 = boto3.client("s3")
response = s3.list_buckets()
for bucket in response["Buckets"]:
    print(bucket["Name"], bucket["CreationDate"].date())

priya-notes-2026 2026-10-12
rohtak-shop-invoices 2026-10-28

Both commands call the same ListBuckets API. The console calls it too when you open the S3 page. That is why anything you learn in the console can later be automated.

Words you will meet everywhere

• AWS account: your container for resources and bills. Everything you create belongs to one account, identified by a 12-digit number. This course uses the example account 111122223333.
• Region: a geographic area with its own data centres, such as Asia Pacific (Mumbai), code ap-south-1. Most resources live in one Region.
• Availability Zone (AZ): one or more separate data centres inside a Region.
• IAM: Identity and Access Management, the service that decides who may call which API.
• ARN: Amazon Resource Name, the full unique name of a resource.

An ARN has a fixed shape: arn:partition:service:region:account-id:resource. Two real-looking examples:

arn:aws:lambda:ap-south-1:111122223333:function:exam-results
arn:aws:s3:::priya-notes-2026

The Lambda ARN contains the Region and the account. The S3 bucket ARN leaves both empty, because bucket names are global and the ARN does not need them.

How this course is organised

You will start with cloud basics and a safe account setup, because mistakes there cost real money. Then you learn identity (IAM), the core services (EC2, S3, VPC, databases, Lambda), how to deliver and monitor applications, and how to describe infrastructure as code. The last section covers architecture, costs, AI services, certifications, and a project where you host a real website with a small API.

Common mistakes

• Thinking the cloud is free or unlimited. You pay for what you leave running, even when nobody uses it. Always clean up after practice.
• Doing everything as the root user. The email-and-password owner of the account should almost never be used. You will set up safer access in the next lessons.
• Creating resources in a random Region. Check the Region selector at the top right of the console before you click Create. Resources in another Region are easy to forget.
• Copying commands without reading them. A single command can create something that is billed every hour. Understand what it does first.

Key points

• AWS is Amazon's cloud platform with more than 200 services that you rent on demand and pay for as you use them.
• Real applications combine building blocks such as S3, EC2, RDS, Lambda, CloudFront and IAM.
• The console, CLI, SDKs and infrastructure-as-code tools all call the same AWS APIs.
• An account holds your resources; a Region is a geographic area; an Availability Zone is a separate data centre inside it.
• An ARN uniquely names a resource in the form arn:partition:service:region:account-id:resource.

partition: aws
service:   dynamodb
region:    ap-south-1
account:   111122223333
resource:  table/MatchScores

arn:aws:lambda:ap-south-2:111122223333:function:send-receipt