✅ 1. What is AWS?

AWS (Amazon Web Services) is a cloud computing platform offering compute, storage, databases, networking, and AI services on demand.

Diagram — AWS Cloud Overview

                ┌─────────────────────────────┐
                │           AWS Cloud          │
                │  (Global Infrastructure)     │
                └──────────────┬──────────────┘
          ┌──────────────┬──────────────┬──────────────┐
          ▼              ▼              ▼               ▼
      Compute         Storage        Database         Network
   (EC2, Lambda)   (S3, EBS, FSx)  (RDS, DynamoDB)   (VPC, Route53)

✅ 2. What is EC2?

Amazon EC2 (Elastic Compute Cloud) provides virtual servers in the cloud.

Diagram — EC2 Instance Concept

┌────────────────────────┐
│      EC2 INSTANCE       │
├────────────────────────┤
│  vCPU, RAM, OS, Disk    │
│  Security Groups         │
│  Key Pair (SSH Login)   │
└────────────────────────┘
         │
         ▼
Runs your applications

Best Answer

EC2 allows scalable compute capacity in the cloud. You can choose instance types, OS, security, storage, and networking.

✅ 3. What is S3?

Amazon S3 is a scalable object storage service for storing files, images, backups, logs, etc.

Diagram — S3 Data Structure

          S3 BUCKET
┌──────────────────────────┐
│  Folder1 /               │
│     └── file1.jpg        │
│  Folder2 /               │
│     └── data.json        │
│  log.txt                 │
└──────────────────────────┘

Key Features

• 99.999999999% durability
• Versioning
• Lifecycle rules
• Buckets & objects
• Encryption

✅ 4. What is an AWS VPC?

A Virtual Private Cloud (VPC) is your isolated network inside AWS.

Diagram — VPC Structure

                     AWS REGION
        ┌────────────────────────────────────┐
        │                VPC                 │
        │ ┌──────────────┐   ┌─────────────┐│
        │ │ Public Subnet│   │PrivateSubnet││
        │ │ EC2 + ELB    │   │   DB Server ││
        │ └──────────────┘   └─────────────┘│
        │        │                 ▲         │
        │ Internet GW ─────────────┘         │
        └────────────────────────────────────┘

✅ 5. Explain IAM (Identity and Access Management).

IAM manages users, roles, and permissions securely.

Diagram — IAM Access Flow

User → IAM Policy → AWS Service Access Decision

Best Answer

IAM allows you to define who can access which AWS services. You assign users, groups, roles, and policies to control permissions.

✅ 6. What is Lambda?

AWS Lambda allows you to run code without managing servers.

Diagram — Lambda Flow

Event Trigger → Lambda Function → Output

Examples of Events

• API Gateway
• S3 upload
• CloudWatch schedule
• DynamoDB stream

✅ 7. What is CloudFront?

AWS CloudFront is a Content Delivery Network (CDN) that reduces latency.

Diagram — CloudFront Delivery

User Request → Nearest Edge Location → Cached Content

✅ 8. What is Auto Scaling?

Auto Scaling automatically adjusts your EC2 instances based on load.

Diagram — Scaling Logic

     CPU > 80% → Scale Out (Add Instances)
     CPU < 30% → Scale In  (Remove Instances)

✅ 9. What is RDS?

RDS is a fully managed relational database service (MySQL, Postgres, Oracle, SQL Server).

Diagram — RDS Architecture

        ┌───────────────┐
        │   App Server   │
        └───────┬───────┘
                ▼
        ┌───────────────┐
        │     RDS        │
        │ Multi-AZ, Backups│
        └───────────────┘

✅ 10. What is DynamoDB?

DynamoDB is a fully managed NoSQL database with instant scaling.

Diagram — DynamoDB Table

TABLE: Users
┌───────────────┬───────────────┐
│ user_id (PK)  │ name           │
├───────────────┼───────────────┤
│ 101           │ Alice          │
│ 102           │ Bob            │
└───────────────┴───────────────┘

✅ 11. Explain Elastic Load Balancer (ELB).

ELB distributes traffic across multiple EC2 instances.

Diagram — ELB Traffic Flow

       ┌─────────────┐
User → │     ELB     │ → EC2-1
       └─────────────┘   EC2-2

✅ 12. What are Availability Zones?

Availability Zones = isolated data centers within a region.

Diagram — Region vs AZ

AWS Region
├── AZ-1
├── AZ-2
└── AZ-3

✅ 13. What is Route 53?

AWS DNS service for domain routing.

Diagram — Route 53 Flow

User → DNS Lookup → Route53 → Server/IP

✅ 14. What is AWS CloudWatch?

CloudWatch monitors logs, metrics, alarms.

Diagram — CloudWatch Monitoring

Logs + Metrics → Dashboards → Alerts → Actions

✅ 15. What is AWS CloudTrail?

CloudTrail tracks all API calls for security auditing.

User Action → CloudTrail Log → Stored in S3

🟩 16. What is Elastic Beanstalk?

A platform that deploys web apps automatically.

Upload Code → Beanstalk → EC2 + Load Balancer + Auto Scaling

🟦 17. What is AWS SNS?

Simple Notification Service — sends messages.

Event → SNS Topic → Subscribers

🟨 18. What is AWS SQS?

Simple Queue Service — decouples systems.

Producer → SQS Queue → Consumer

🟥 19. Difference: S3 vs EBS vs EFS

S3  = Object Storage (files, media, backups)
EBS = Block Storage for EC2 (fast local disk)
EFS = Shared File System (Linux)

🟪 20. Difference: RDS vs DynamoDB

RDS        → relational (SQL)
DynamoDB   → NoSQL (key-value)