What is AWS?

What is Cloud Computing?

Cloud computing is the practice of using computing resources over the internet instead of owning and maintaining physical hardware.

These resources include:

• Virtual servers

• Storage systems

• Databases

• Networking

• Software and tools

In cloud computing:

• You do not buy physical servers

• You do not manage data centers

• Resources are available instantly

• You pay only for what you use

Cloud computing removes the need for upfront infrastructure investment and allows applications to scale easily based on demand.

What is AWS?

Amazon Web Services (AWS) is a cloud computing platform provided by Amazon that offers on demand infrastructure and managed services.

AWS provides:

• Computing power

• Storage solutions

• Database services

• Networking capabilities

• Security and monitoring tools

AWS allows developers and companies to:

• Deploy applications within minutes

• Scale applications automatically

• Run workloads globally

• Reduce infrastructure and operational costs

AWS is used by startups, enterprises, and global companies to build reliable and scalable applications.

Why AWS?

Pay As You Go Pricing

• No upfront hardware cost

• No long term contracts

• Charges based on actual usage

• Ideal for beginners and startups

• Free Tier available for learning

Scalability and Elasticity

• Resources can scale up automatically when traffic increases

• Resources can scale down when demand reduces

• No manual server management required

• Helps handle sudden traffic spikes efficiently

Global Reach

• AWS operates data centers in multiple regions worldwide

• Applications can be deployed closer to users

• Reduces latency and improves performance

• Supports global and multi-region applications

Reliability and Security

• High availability using multiple Availability Zones

• Built in fault tolerance

• Strong security services for access control

• Data encryption and monitoring supported

Cloud Service Models

IaaS (Infrastructure as a Service)

• Provides virtual machines and infrastructure

• User manages:

  • Operating system

  • Applications

  • Data

• Cloud provider manages:

  • Physical servers

  • Networking

  • Virtualization
    Examples: Amazon EC2, Amazon EBS

PaaS (Platform as a Service)

• Provides a ready to use platform for application development

• User manages:

  • Application code

  • Data

• Cloud provider manages:

  • Operating system

  • Runtime environment

  • Infrastructure
    Examples: AWS Elastic Beanstalk, Amazon RDS

SaaS (Software as a Service)

• Fully managed software delivered over the internet

• No infrastructure or platform management required

• Accessible through web browsers or APIs
  Examples: Gmail, Google Docs, Zoom

AWS Global Infrastructure

What is AWS Global Infrastructure?

AWS Global Infrastructure is the physical backbone of AWS that allows applications to run securely, reliably, and with low latency across the world.

It is designed to:

• Serve users globally

• Provide high availability

• Ensure fault tolerance

• Reduce application downtime

AWS Region

An AWS Region is a geographical area where AWS has multiple data centers.

Key points:

• Each region is completely independent

• Regions are located across different countries

• Data stays within the selected region unless explicitly transferred

• Examples: Asia Pacific (Mumbai), US East (N. Virginia), Europe (Frankfurt)

Why regions matter:

• Compliance and data residency

• Lower latency for users

• Disaster recovery planning

Availability Zones (AZs)

An Availability Zone is a physically separate data center within a region.

Key points:

• Each region has multiple AZs

• AZs are isolated but connected with high speed networks

• Designed to prevent failure impact from one AZ to another

Why AZs matter:

• High availability

• Fault tolerance

• Zero or minimal downtime during failures

Example:

• Deploying an application across multiple AZs ensures it remains available even if one AZ fails.

Edge Locations

Edge Locations are AWS data centers used to deliver content with low latency to users.

Key points:

• Used mainly by services like CloudFront

• Content is cached closer to end users

• Improves performance for static and dynamic content

Why edge locations matter:

• Faster content delivery

• Reduced load on origin servers

• Better user experience globally

Region vs Availability Zone vs Edge Location

• Region: Large geographical area containing multiple AZs

• Availability Zone: Isolated data center within a region

• Edge Location: Used for content delivery and caching

Why Multi AZ Architecture is Important

• Improves application availability

• Protects against data center failures

• Ensures business continuity

• Recommended best practice for production workloads

How AWS Global Infrastructure Helps Applications

• Enables global deployment

• Supports disaster recovery

• Improves performance and reliability

• Provides strong fault tolerance

Identity and Access Management (IAM) & Security

What is IAM?

AWS Identity and Access Management (IAM) is a service that helps you securely control access to AWS resources. It allows you to define who can access AWS and what actions they are allowed to perform.

IAM is a global service, meaning it applies across all AWS regions and is used as the foundation for securing AWS accounts.

IAM Users

An IAM User represents an individual person or application that interacts with AWS.

Each IAM user:

• Has a unique identity

• Can log in to the AWS Management Console

• Can access AWS services using CLI or SDK

• Gets permissions through IAM policies

IAM users are commonly created for developers, admins, or applications that require long term access.

IAM Groups

IAM Groups are used to manage permissions for multiple users together. Instead of assigning permissions to each user individually, permissions are assigned to the group.

Key characteristics:

• Groups contain users only

• Permissions are applied at the group level

• A user can be part of multiple groups

This makes permission management easier and more organized.

IAM Roles

IAM Roles are designed to provide temporary permissions without sharing long-term credentials.

Unlike users, roles:

• Do not have passwords or access keys

• Are assumed by AWS services or users

• Are commonly used for service to service communication

For example, an EC2 instance can assume a role to access S3 securely.

IAM Policies

IAM Policies define permissions in AWS. They specify what actions are allowed or denied on which resources.

Policies:

• Are written in JSON format

• Contain rules called statements

• Can be attached to users, groups, or roles

Each policy statement includes:

• Effect (Allow or Deny)

• Actions

• Resources

Principle of Least Privilege

The principle of least privilege means giving only the minimum permissions required to perform a task.

By following this principle:

• Security risks are reduced

• Accidental changes are prevented

• AWS accounts remain more secure

AWS Shared Responsibility Model

AWS security follows a shared responsibility model where security is divided between AWS and the user.

AWS is responsible for:

• Physical data centers

• Hardware and networking

• Infrastructure security

The user is responsible for:

• IAM configuration

• Application security

• Data protection and encryption

• OS and patch management for EC2

IAM Security Best Practices

To secure AWS accounts effectively:

• Avoid using the root account for daily tasks

• Enable multi factor authentication (MFA)

• Use IAM roles instead of access keys where possible

• Rotate credentials regularly

• Monitor activity using AWS CloudTrail

Compute Services

Amazon EC2 (Elastic Compute Cloud)

Amazon EC2 is a service that provides virtual servers in the cloud. It allows users to run applications on scalable computing capacity without owning physical hardware.

With EC2, you can choose the operating system, instance type, and storage based on your application needs.

Key features of EC2:

• On demand virtual machines

• Full control over OS and software

• Multiple instance types for different workloads

• Integration with other AWS services

EC2 Instance Types

EC2 instances are categorized based on workload requirements.

Common categories include:

• General Purpose – balanced compute, memory, and networking

• Compute Optimized – CPU intensive tasks

• Memory Optimized – memory intensive applications

• Storage Optimized – high disk performance

Choosing the right instance type helps optimize performance and cost.

Security Groups

Security Groups act as a virtual firewall for EC2 instances. They control inbound and outbound traffic at the instance level.

Important points:

• Allow rules only (no deny rules)

• Stateful in nature

• Applied directly to EC2 instances

• Commonly used to allow HTTP, HTTPS, and SSH access

Key Pairs

Key Pairs are used to securely connect to EC2 instances.

Key characteristics:

• Consist of a public key and a private key

• Private key is used to log in to the instance

• Required for SSH access to Linux instances

Key pairs help prevent unauthorized access to EC2 servers.

Auto Scaling

Auto Scaling automatically adjusts the number of EC2 instances based on demand. It ensures applications have the right amount of compute capacity at all times.

Auto Scaling helps with:

• High availability

• Cost optimization

• Automatic scaling during traffic spikes

• Replacing unhealthy instances

Elastic Load Balancer (ELB)

Elastic Load Balancer distributes incoming traffic across multiple EC2 instances to improve availability and fault tolerance.

Benefits of using ELB:

• Prevents overloading a single server

• Improves application reliability

• Works with Auto Scaling

• Supports health checks

Types of Load Balancers

AWS provides different types of load balancers based on use case:

• Application Load Balancer (ALB) – Layer 7, used for HTTP/HTTPS

• Network Load Balancer (NLB) – Layer 4, high-performance use cases

• Classic Load Balancer – legacy option

How These Services Work Together

In a typical architecture:

• EC2 instances run the application

• ELB distributes traffic across instances

• Auto Scaling adjusts the number of instances based on demand

• Security Groups control access to the instances

This combination ensures scalability, availability, and security.

Storage Services

Amazon S3 (Simple Storage Service)

Amazon S3 is an object storage service designed to store and retrieve any amount of data from anywhere on the internet. It is highly scalable, durable, and commonly used as the default storage service in AWS.

In S3, data is stored as objects inside buckets rather than traditional folders or disks.

Key characteristics of S3:

• Unlimited storage capacity

• Data stored as objects (files + metadata)

• Highly durable and available

• Accessible via web, CLI, or SDK

S3 Buckets and Objects

An S3 bucket is a container for storing objects.

Important points:

• Bucket names must be globally unique

• Buckets are created in a specific region

• Objects are the actual files stored in buckets

Each object consists of:

• Object data (file)

• Metadata

• Unique object key

S3 Storage Classes

S3 provides different storage classes based on access frequency and cost.

Common storage classes:

• S3 Standard – frequently accessed data

• S3 Intelligent-Tiering – automatic cost optimization

• S3 Standard-IA – infrequently accessed data

• S3 Glacier – archival and long-term storage

Choosing the right storage class helps reduce storage costs.

S3 Security and Access Control

S3 security is managed using:

• Bucket policies

• IAM policies

• Public and private access settings

Key points:

• Buckets are private by default

• Public access must be explicitly enabled

• Supports encryption at rest and in transit

Amazon EBS (Elastic Block Store)

Amazon EBS provides block level storage that is attached to EC2 instances. It behaves like a physical hard drive for virtual servers.

EBS is mainly used for:

• Operating systems

• Databases

• Application files that require low latency

Key features of EBS:

• Persistent storage

• High performance

• Automatically replicated within an Availability Zone

S3 vs EBS

S3 and EBS serve different purposes in AWS.

Main differences:

• S3 is object storage, EBS is block storage

• S3 is accessed over the internet, EBS is attached to EC2

• S3 is highly durable across AZs, EBS is limited to one AZ

• S3 is ideal for backups and static content, EBS for OS and databases

Amazon EFS (Elastic File System)

Amazon EFS is a managed file storage service that can be shared across multiple EC2 instances.

EFS provides:

• File-based storage

• Automatic scaling

• Access from multiple EC2 instances simultaneously

It is commonly used for:

• Shared application files

• Content management systems

• Microservices requiring shared storage

When to Use Which Storage

• Use S3 for backups, static files, logs, and media

• Use EBS for EC2 operating systems and databases

• Use EFS when multiple EC2 instances need shared access

Database Services

Amazon RDS (Relational Database Service)

Amazon RDS is a managed relational database service that makes it easy to set up, operate, and scale relational databases in the cloud.

With RDS, AWS handles most of the database administration tasks, allowing developers to focus on application logic instead of database maintenance.

RDS supports popular database engines:

• MySQL

• PostgreSQL

• MariaDB

• Oracle

• SQL Server

Key Features of RDS

RDS provides several built in features that simplify database management:

• Automated backups

• Database snapshots

• Automatic patching

• Monitoring and performance metrics

• High availability using Multi-AZ deployment

These features help ensure reliability and data safety.

RDS Multi-AZ Deployment

Multi-AZ deployment creates a standby replica of the database in another Availability Zone.

Important points:

• Improves availability and fault tolerance

• Automatic failover during outages

• No manual intervention required

• Mainly used for production environments

Amazon DynamoDB

Amazon DynamoDB is a fully managed NoSQL key value database designed for high performance and massive scalability.

Unlike relational databases, DynamoDB does not use tables with joins. It stores data as items identified by primary keys.

Key characteristics:

• Serverless and fully managed

• Single digit millisecond latency

• Automatic scaling

• Highly available across multiple AZs

DynamoDB Data Model

DynamoDB organizes data using:

• Tables

• Items (rows)

• Attributes (columns)

Each item is uniquely identified using:

• Partition key

• Optional sort key

This design allows DynamoDB to scale horizontally with minimal latency.

RDS vs DynamoDB

RDS and DynamoDB are used for different types of applications.

Main differences:

• RDS is relational, DynamoDB is NoSQL

• RDS supports complex queries and joins

• DynamoDB is designed for high-scale, low-latency workloads

• RDS is ideal for structured data, DynamoDB for flexible schemas

When to Use Which Database

• Use RDS when you need relational data, transactions, and complex queries

• Use DynamoDB when you need high scalability and low latency

• Choose based on application requirements and access patterns

Networking Basics

Amazon VPC (Virtual Private Cloud)

Amazon VPC is a logically isolated virtual network where you launch AWS resources like EC2, RDS, and Load Balancers.

A VPC gives you control over:

• IP address range

• Subnets

• Routing

• Network security

It acts like your own private data center inside AWS.

Subnets

A subnet is a range of IP addresses within a VPC. Subnets allow you to organize and isolate resources.

There are two main types of subnets:

• Public Subnet – resources have access to the internet

• Private Subnet – resources do not have direct internet access

Best practice:

• Place load balancers in public subnets

• Place databases in private subnets

Internet Gateway (IGW)

An Internet Gateway allows communication between resources in a VPC and the internet.

Key points:

• Attached to a VPC

• Enables inbound and outbound internet traffic

• Required for public subnets to access the internet

Without an Internet Gateway, resources remain isolated from the public internet.

Route Tables

Route tables control how network traffic flows within a VPC.

Each route table contains:

• Destination (IP range)

• Target (IGW, NAT Gateway, or local)

Important points:

• Every subnet must be associated with a route table

• Routes determine whether a subnet is public or private

NAT Gateway

A NAT Gateway allows instances in a private subnet to access the internet without being exposed to inbound traffic.

Use cases:

• Download updates

• Access external APIs

• Maintain security for private resources

NAT Gateways are commonly used for backend servers.

Security Groups

Security Groups act as virtual firewalls at the instance level.

Key characteristics:

• Stateful

• Allow rules only

• Applied to EC2 and other resources

• Control inbound and outbound traffic

Security Groups are the first layer of network security.

Network ACLs (NACLs)

Network ACLs provide security at the subnet level.

Key characteristics:

• Stateless

• Support allow and deny rules

• Applied to all resources in a subnet

NACLs act as an additional layer of security.

Security Groups vs Network ACLs

Security Groups:

• Operate at instance level

• Stateful

• Only allow rules

Network ACLs:

• Operate at subnet level

• Stateless

• Allow and deny rules

How Networking Components Work Together

In a typical setup:

• VPC provides the network

• Subnets divide the network

• Route tables control traffic flow

• Internet Gateway enables internet access

• Security Groups and NACLs secure resources

Monitoring & Logging

Amazon CloudWatch

Amazon CloudWatch is a monitoring service that helps you observe and track the performance of AWS resources and applications in real time.

CloudWatch collects metrics, logs, and events, allowing teams to detect issues early and maintain system health.

Key capabilities of CloudWatch:

• Resource performance monitoring

• Application log collection

• Custom metrics support

• Alarm and notification setup

CloudWatch Metrics

Metrics are numerical data points that represent the performance of AWS resources.

Common metrics include:

• CPU utilization

• Memory usage

• Disk I/O

• Network traffic

Metrics help identify performance bottlenecks and resource utilization trends.

CloudWatch Logs

CloudWatch Logs store and manage log files generated by AWS services and applications.

Important uses:

• Debugging application issues

• Analyzing system behavior

• Centralized log management

Logs can be collected from EC2, Lambda, and other AWS services.

CloudWatch Alarms

CloudWatch Alarms monitor metrics and trigger actions when thresholds are crossed.

Alarms can:

• Send notifications via SNS

• Trigger Auto Scaling actions

• Help respond to incidents quickly

Example:

• Alert when CPU usage exceeds a defined limit.

AWS CloudTrail

AWS CloudTrail is a service that records API calls and account activity in your AWS account.

CloudTrail helps with:

• Security auditing

• Compliance monitoring

• Tracking who did what and when

• Investigating suspicious activity

CloudTrail Logs

CloudTrail logs include:

• Identity of the caller

• Time of the API request

• Source IP address

• Actions performed

These logs are useful for auditing and security analysis.

CloudWatch vs CloudTrail

CloudWatch focuses on:

• Performance monitoring

• Resource health

• Logs and alarms

CloudTrail focuses on:

• User activity

• API call history

• Security and compliance

Why Monitoring and Logging Matter

Monitoring and logging ensure:

• High application availability

• Faster issue detection

• Better security visibility

• Improved system reliability

DevOps & Deployment Basics (CI/CD)

What is DevOps?

DevOps is a set of practices that aims to reduce the gap between development and operations teams. It focuses on automating software delivery, improving collaboration, and ensuring faster and reliable releases.

DevOps helps teams:

• Release features faster

• Reduce deployment failures

• Improve system stability

• Automate repetitive tasks

What is CI/CD?

CI/CD stands for Continuous Integration and Continuous Deployment.

• Continuous Integration (CI) is the practice of automatically building and testing code whenever changes are pushed.

• Continuous Deployment (CD) is the practice of automatically deploying tested code to production or staging environments.

CI/CD ensures that applications are always in a deployable state.

CI/CD in AWS

AWS provides managed services to build complete CI/CD pipelines without managing servers.

AWS CI/CD services include:

• CodeCommit

• CodeBuild

• CodeDeploy

• CodePipeline

These services integrate well with each other and other AWS services.

AWS CodeCommit

AWS CodeCommit is a fully managed source control service that hosts Git repositories.

Key points:

• Secure and scalable Git repositories

• Integrated with IAM for access control

• Used to store application source code

AWS CodeBuild

AWS CodeBuild is a build service that compiles source code, runs tests, and produces build artifacts.

CodeBuild:

• Automatically scales build resources

• Supports multiple programming languages

• Eliminates the need to manage build servers

AWS CodeDeploy

AWS CodeDeploy is used to automate application deployments to compute services like EC2 and Lambda.

It helps:

• Reduce deployment downtime

• Handle rolling and blue-green deployments

• Monitor deployment success or failure

AWS CodePipeline

AWS CodePipeline is a CI/CD orchestration service that automates the entire release process.

Pipeline stages typically include:

• Source

• Build

• Test

• Deploy

CodePipeline connects all CI/CD services into a single automated workflow.

How CI/CD Works in AWS

In a typical setup:

• Code is pushed to CodeCommit

• CodeBuild builds and tests the application

• CodeDeploy deploys the application

• CodePipeline manages the entire flow

This automation ensures consistent and reliable deployments.

Serverless Basics

What is Serverless?

Serverless is a cloud computing model where developers do not manage servers. The cloud provider automatically handles infrastructure provisioning, scaling, and maintenance.

In serverless architecture:

• No server management is required

• Applications scale automatically

• Billing is based on actual execution time

AWS Lambda

AWS Lambda is a serverless compute service that runs code in response to events without provisioning or managing servers.

Lambda allows developers to:

• Run backend logic without managing EC2

• Execute code only when triggered

• Scale automatically based on requests

Key characteristics of Lambda:

• Event-driven execution

• Supports multiple programming languages

• Short-lived executions

• Pay only for execution time

Lambda Triggers

Lambda functions can be triggered by various AWS services.

Common triggers include:

• API Gateway

• S3 events

• DynamoDB streams

• CloudWatch events

This makes Lambda suitable for building event-driven systems.

Amazon API Gateway

Amazon API Gateway is a managed service that allows you to create, publish, and manage APIs.

API Gateway is commonly used to:

• Expose backend services to frontend applications

• Connect Lambda functions to HTTP endpoints

• Secure APIs using authentication and throttling

Lambda + API Gateway Architecture

In a typical serverless setup:

• API Gateway receives HTTP requests

• Requests trigger Lambda functions

• Lambda processes the logic

• Response is returned to the client

This architecture is widely used for building scalable backend APIs.

Benefits of Serverless Architecture

Serverless provides:

• Automatic scaling

• High availability

• Reduced operational overhead

• Cost efficiency for low-to-medium workloads

Pricing & Cost Management

AWS Pricing Model

AWS follows a pay-as-you-go pricing model, meaning you only pay for the resources you use. There are no upfront costs for most services, making it flexible for beginners and businesses.

Key points:

• Pay per compute hour, storage, or request

• Free Tier available for 12 months on selected services

• Pricing varies by region and service type

• Allows cost optimization based on usage

AWS Free Tier

The AWS Free Tier allows new users to experiment and learn AWS services without incurring charges.

Free Tier includes:

• 750 hours of EC2 t2.micro instances per month

• 5 GB of S3 standard storage

• 750 hours of RDS Single-AZ db.t2.micro

• Free Lambda requests up to 1 million per month

Cost Optimization Strategies

To manage costs efficiently:

• Use Auto Scaling to adjust resources dynamically

• Choose right instance types for workloads

• Use S3 storage classes based on access patterns

• Delete unused resources

• Monitor usage using AWS Cost Explorer

Billing and Monitoring Tools

AWS provides tools to track and manage costs:

• AWS Cost Explorer – visualize and analyze costs

• AWS Budgets – set alerts for budget thresholds

• AWS Trusted Advisor – recommendations to reduce cost

Why Cost Management is Important

• Prevents unexpected bills

• Ensures efficient resource usage

• Helps optimize architecture

• Essential for startups and personal projects

Real World Example: Hosting a Web Application on AWS

Scenario

You want to host a simple web application that serves users globally, stores data, and scales automatically with traffic.

AWS services used:

• EC2 for web servers

• S3 for static assets

• RDS for relational database

• VPC for networking

• Security Groups and IAM for access control

• CloudWatch for monitoring

• Auto Scaling and ELB for scalability

• Lambda + API Gateway for serverless backend (optional)

Architecture Flow

1. VPC & Subnets

   • Public subnet hosts EC2 web servers

   • Private subnet hosts RDS database

2. Elastic Load Balancer (ELB)

   • Distributes incoming traffic across EC2 instances

   • Ensures high availability

3. Auto Scaling

   • Automatically adds or removes EC2 instances based on demand

   • Reduces cost and handles traffic spikes

4. S3 Storage

   • Stores images, CSS, JavaScript files, and backups

   • Can serve static content globally

5. IAM & Security

   • Users, roles, and policies manage access to AWS resources

   • Security Groups control inbound and outbound traffic

6. Monitoring & Logging

   • CloudWatch monitors metrics like CPU, memory, and traffic

   • CloudTrail tracks API calls and user activity

7. Optional Serverless Backend

   • Lambda functions handle API requests

   • API Gateway exposes HTTP endpoints

   • Reduces server management overhead

Benefits of This Architecture

• High availability across multiple Availability Zones

• Automatic scaling based on traffic

• Secure access control with IAM and Security Groups

• Centralized monitoring and alerting

• Cost-efficient by paying only for resources used

This architecture demonstrates a typical end-to-end AWS setup for a beginner to understand how multiple services work together in a real-world scenario.