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Mastering Amazon EC2

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1. What is Amazon EC2?
Amazon EC2 (Elastic Compute Cloud) is a web service that provides resizable compute capacity in the cloud. It’s designed to make web-scale cloud computing easier for developers. You can launch virtual servers (instances), configure networking and security, and manage storage.

Core Capabilities:

  • Launch and terminate instances on demand.
  • Choose AMIs to define OS and software.
  • Select instance types based on workload.
  • Automate scaling and high availability.
  • Integrate with Elastic Load Balancer and Auto Scaling.

2. EC2 Instance Lifecycle

  • Pending – Instance is being launched.
  • Running – Instance is active.
  • Stopping – Instance is shutting down.
  • Stopped – Instance is off but data is intact.
  • Terminated – Instance is permanently deleted.
  • EC2 Instance Types (With Use Cases)

  1. General Purpose
    • t4g, t3, t2 – Low-cost, burstable performance.
    • Use Case: Development, testing, web servers.

  2. Compute Optimized
    • c7g, c6g, c5 – High-performance CPU.
    • Use Case: Batch processing, game servers, ML inference.

  3. Memory Optimized
    • r6g, r5, x2idn – Large memory capacity.
    • Use Case: In-memory DBs, real-time analytics.

  4. Storage Optimized
    • i4i, d3en, h1 – High IOPS and throughput.
    • Use Case: NoSQL DBs, big data workloads.

  5. Accelerated Computing
    • p4, inf2, g5 – GPU-based.
    • Use Case: AI/ML, video processing, 3D rendering.

4. Purchasing Options

  • On-Demand Instances
    • No upfront cost. Pay per second.
    • Ideal for unpredictable workloads.

  • Reserved Instances (RIs)
    • Commitment (1 or 3 years).
    • Up to 75% cost savings.
    • Convertible or Standard RIs.

  • Savings Plans
    • Commitment on usage (EC2, Fargate, Lambda).
    • More flexibility than RIs.

  • Spot Instances
    • Use spare capacity.
    • Up to 90% discount.
    • Suitable for fault-tolerant workloads.

  • Dedicated Hosts
    • Physical server for your use.
    • Bring Your Own License (BYOL).

5. Elastic Load Balancing (ELB)
Distributes traffic to multiple EC2s.
Types:
• Application Load Balancer (ALB): HTTP, Web apps.
• Network Load Balancer (NLB): TCP, low latency.
• Gateway Load Balancer (GWLB): Third-party appliances.

Features:
• Health checks.
• Sticky sessions.
• SSL termination.

6. EC2 Auto Scaling
Auto Scaling ensures availability and cost efficiency.
Components:
• Launch Template/Config
• Auto Scaling Group (ASG)
• Scaling Policies: Target, step, scheduled

Advanced Strategies:
• Predictive scaling
• Lifecycle hooks
• Warm pools

7. EC2 Storage and Volumes
EBS (Elastic Block Store):
• gp3: General purpose
• io1/io2: High IOPS
• st1/sc1: Throughput and archival

Instance Store:
• High-speed, ephemeral
• Data lost on stop/terminate

EFS (Elastic File System):
• NFS file system
• Scalable across multiple EC2

Amazon FSx:
• Windows File Server, Lustre, NetApp ONTAP

8. AMIs and Snapshots
Amazon Machine Image (AMI):
• Template to launch instances
• Includes OS, configuration, apps

Snapshots:
• Point-in-time backups of EBS volumes
• Used to create AMIs

Golden AMI Strategy:
• Hardened base image
• Pre-installed apps and security settings

9. Backup Strategies

EBS Snapshots:
• Manual or scheduled
• Incremental backups

AMI-Based Backups:
• Save complete OS and data state

AWS Backup:
• Centralized backup across services

Cross-region Backup:
• Enable DR and compliance

10. EC2 Security Best Practices
Key Concepts:
• Security Groups: Instance-level firewall
• NACLs: Subnet-level control
• Key Pairs: SSH authentication
• IAM Roles: Secure access to AWS services
• SSM: Secure shell-free management

Hardening Tips:
• Disable root login
• Regular patching
• Use least privilege IAM policies

11. Monitoring and Logging

CloudWatch:
• EC2 metrics, custom alarms
• Log agent for file-level monitoring

CloudTrail:
• Record API activity

EC2 Detailed Monitoring:
• 1-minute interval metrics

AWS Config:
• Audit and compliance checks

12. Server Connectivity & Session Management
Linux:
• SSH with PEM key
• SSM Session Manager
Windows:
• RDP (Remote Desktop Protocol)
• EC2 Connect for browser-based access
Connection Tools:
• Putty, Mobaxterm, VS Code SSH plugin

13. High Availability and Cost Optimization
High Availability:
• Deploy in multiple AZs
• Use Load Balancer + Auto Scaling
• Elastic IP for static access

Cost Optimization:
• Choose right instance type
• Use Spot and RIs where suitable
• Use Auto Scaling to scale down
• Schedule non-production shutdown

14. Real-Time Use Cases

  1. Web Hosting: Scalable app hosting with Auto Scaling + ALB
  2. Batch Jobs: Use Spot Instances for cost-effective processing
  3. Gaming: Low-latency game server on EC2
  4. CI/CD Runners: Host Jenkins or GitHub runners
  5. Dev/Test Environments: Spin up/down quickly
  6. AI/ML Training: Use GPU-based instances

  7. EC2 Interview Questions
    Basic:
    • What is EC2?
    • How do you connect to EC2?
    • What are the differences between AMI and Snapshot?
    Intermediate:
    • How does Auto Scaling work?
    • Difference between Security Group and NACL?
    • What is the difference between instance store and EBS?
    Advanced:
    • Design a fault-tolerant EC2 architecture.
    • How do you implement patch management in EC2?
    • How do you maintain golden AMIs?
    • How do you monitor 100+ EC2 instances efficiently?

                                © 2025 Kranthi – AWS Community Builder

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