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Hritik Raj
Hritik Raj

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🌐 AWS 127: Building from Scratch - Creating a Custom Public VPC

#aws #networking #vpc #100daysofcloud

AWS

🏗️ Cloud Infrastructure 101: Designing Your Own Network

Hey Cloud Architects 👋

Welcome to Day 27 of the #100DaysOfCloud Challenge!
Today, we are stepping away from the default AWS settings and building our own Custom VPC. The Networking Team needs a dedicated space for public-facing services, complete with automated IP assignment and secure SSH access.

This task is part of my hands-on practice on the KodeKloud Engineer platform, which I highly recommend for anyone looking to master real-world DevOps scenarios.

🎯 Objective

  • Create a custom VPC named devops-pub-vpc.
  • Create a public subnet named devops-pub-subnet.
  • Enable Auto-assign public IPv4 address for the subnet.
  • Launch a t2.micro instance named devops-pub-ec2 inside this network.
  • Ensure Port 22 (SSH) is open to the internet.

💡 Why a Custom VPC is Essential

While AWS provides a "Default VPC," professional DevOps teams build custom networks to ensure better security, isolation, and control over IP addressing.

🔹 Key Concepts

  • VPC (Virtual Private Cloud) A logically isolated section of the AWS Cloud where you can launch resources in a virtual network that you define.

  • Internet Gateway (IGW) The "bridge" that connects your VPC to the internet. Without an IGW, your "public" subnet remains private.

  • Route Tables These act as the "GPS" for your network, telling traffic how to reach the Internet Gateway to go outside the VPC.

🛠️ Step-by-Step: Custom Networking Workflow

We’ll move from Network Creation → Routing → Instance Provisioning.

🔹 Phase A: Create the VPC & Subnet

  • Create VPC: Navigate to the VPC Dashboard and click "Create VPC". Name it devops-pub-vpc.

  • Create Subnet: Create a new subnet within this VPC named devops-pub-subnet.
  • Enable Public IPs: This is a crucial step! Go to Subnet Settings and check the box for "Enable auto-assign public IPv4 address". This ensures every instance you launch here gets a Public IP automatically.

🔹 Phase B: Configure Internet Access (The "Public" Part)

  • Internet Gateway: Create an IGW and Attach it to your devops-pub-vpc.

  • Update Route Table: Find the Route Table associated with your subnet and add a route:
    • Destination: 0.0.0.0/0 (The Internet)
    • Target: Your Internet Gateway.

🔹 Phase C: Launch the Public Instance

  • Provision EC2: Launch a t2.micro instance named devops-pub-ec2.
  • Network Settings: Be sure to select devops-pub-vpc and devops-pub-subnet in the launch wizard.
  • Security Group: Create a new SG that allows Inbound SSH (Port 22) from Anywhere (0.0.0.0/0).

✅ Verify Success

  • Check Connectivity: Once the instance is "Running," copy its Public IP.
  • Terminal Test: Try connecting via SSH from your local machine or landing host:
    • ssh -i your-key.pem ubuntu@<INSTANCE_PUBLIC_IP>

  • Confirm: 🎉 If you successfully log in, your custom network is officially open for business!

📝 Key Takeaways

  • 🚀 Default vs. Custom: Custom VPCs allow you to define your own CIDR blocks (IP ranges).
  • 🔗 Implicit Dependency: A subnet is only "Public" if it has a route to an Internet Gateway.
  • 🛡️ Security Groups: Even in a public VPC, your instances are protected by Security Groups. Always use the principle of least privilege!

🚫 Common Mistakes

  • Forgetting the IGW: Attaching an IGW is a two-step process: Create it, then Attach it to the VPC.
  • Route Table Missing: If you can't SSH in, check if your Route Table actually points to the IGW.
  • Auto-Assign Disabled: If your instance doesn't have a Public IP address in the console, you forgot to enable the auto-assign setting on the subnet.

🌟 Final Thoughts

You’ve just built the backbone of cloud computing! Understanding VPCs, Subnets, and Routing is what separates a "Cloud User" from a "Cloud Architect." This setup is the starting point for hosting websites, APIs, and much more.

🌟 Practice Like a Pro

If you want to try these tasks yourself in a real AWS environment, check out:
👉 KodeKloud Engineer - Practice Labs

It’s where I’ve been sharpening my skills daily!

🔗 Let’s Connect

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