📅 Day 12 - AWS Practical Learning

✍️ By Parag Kulkarni
🔑 Topics Covered: EC2, Elastic Load Balancer (ELB), Elastic Beanstalk, Lightsail, OSI Model, and Load Balancer Routing

🖥️ EC2 (Elastic Compute Cloud)

✅ What is EC2?

• In EC2 service, we can launch virtual servers (EC2 instances), which are essentially VMs on the cloud.

• EC2 is regional: You must select a region to launch an instance.

AWS services can be:

• • 🌐 Global (e.g., IAM, Route 53)

    • 📍 Regional (e.g., EC2, S3)

⚖️ Elastic Load Balancer (ELB)

💡 ELB Overview

• ELB is a managed service by AWS that helps in distributing incoming traffic across multiple EC2 instances across Availability Zones.

• It ensures high availability, fault tolerance, and auto scaling integration.

🔍 Key ELB Concepts

• ELB is not a server, it’s a service—you cannot log into it.

• You can access ELB via DNS name (URL).

• ELB doesn't reside in a specific Availability Zone; it works at the regional level.

• IP addresses of ELB are dynamic, not static.

• AWS recommends using the DNS name instead of the IP.

🧠 OSI Model Refresher (7 Layers)

1. 🔒 Application (Layer 7)

2. 🎨 Presentation

3. 🔁 Session

4. 🚚 Transport (Layer 4)

5. 🌐 Network (Layer 3)

6. 🔌 Data Link

7. 🧱 Physical

🌱 Elastic Beanstalk

🚀 What is Beanstalk?

• A Platform as a Service (PaaS) that handles the heavy lifting of EC2 instance provisioning, load balancing, auto scaling, and monitoring.

• Ideal for quick deployment of applications (Java, Node.js, Python, etc.).

• You just upload your code—Beanstalk does the rest!

🧩 How Beanstalk Works:

You provide:

• • 🧾 Application code

    • ⚙️ Environment configurations

    • 🧱 Platform (e.g., Java, Node.js)

Beanstalk:

• • Automatically launches EC2

    • Applies configuration

    • Deploys your app

🧠 Unlike traditional PaaS, you have full control over the EC2 instances launched by Beanstalk. You can SSH into them and modify as needed.

🌐 Lightsail — Simplicity First

💡 Why Use Lightsail?

Lightsail is perfect if you want to quickly launch pre-configured servers for:

WordPress

• Joomla

• Drupal

• GitLab

• Redmine

• It’s beginner-friendly and hides infrastructure complexities.

❌ Limitations: Lightsail does not support auto scaling. It's ideal for small-scale or standalone projects.

🌍 Advanced Load Balancer Routing — ALB Rules

🛠️ ALB Routing Methods:

📌 Host-Based Routing:

Routes traffic based on domain name.

• http://parag.com → app 1 http://web.parag.com → app 2

🛤️ Path-Based Routing:

• Routes traffic based on URL path.

• http://parag.com/admin → admin app

🔗 Each rule is linked to a target group, which includes your EC2 instances.

🔐 Gateway Load Balancer (GWLB)

Deploy, manage, and scale third-party network appliances like:

🔥 Firewalls

• 🛡️ Intrusion Prevention Systems

• Uses GENEVE protocol (6081) to tunnel traffic.

• Works at OSI Layer 3 (Network Layer).

📝 Conclusion

If you're beginning your DevOps or Cloud Engineering journey, understanding these core AWS components will make you job-ready in no time. This guide gives you a strong foundation in:

• ✅ EC2 instances

• ✅ Load balancing strategies

• ✅ Platform-as-a-Service using Elastic Beanstalk

• ✅ Lightsail for pre-configured deployment

• ✅ Networking layers & traffic routing in ALB