SimpleTalk — Real-Time Chat Infrastructure on AWS

SimpleTalk is a real-time chat application built with Node.js and Socket.io.

This repository focuses on the production-grade cloud infrastructure required to deploy, secure, and operate the application reliably on AWS. The project demonstrates the transition from local development to a resilient, automated, and secure production deployment.

🔗 Live Demo: http://13.203.228.51:3000
📂 Repository: [Link to your repo]

---

🚩 Problem Statement

Running a Node.js application in production introduces challenges that a simple node server.js approach cannot handle:

• Fragility: Application crashes or terminal closure stops the service.
• Security Risks: Exposing port 3000 directly to the internet is unsafe.
• Manual Deployments: SSH-based deployments are slow and error-prone.
• Downtime: Updates typically interrupt active user connections.

Solution

A fully automated deployment pipeline backed by:

• AWS EC2
• Nginx reverse proxy
• PM2 process manager
• GitHub Actions (self-hosted runner)

This setup enables secure traffic handling, zero-downtime deployments, and automatic recovery from failures.

---

🏗 Architecture Overview

The application is hosted on an Amazon Linux EC2 instance with layered security and automation.

graph TD
    User((User)) -->|HTTP / WebSockets| Internet
    Internet -->|Port 80| SG[AWS Security Group]

    SG --> Nginx[Nginx Reverse Proxy]

    subgraph AWS EC2 Instance
        Nginx --> NodeApp["Node.js App (PM2)"]
        NodeApp --> DB[(MongoDB)]

        GHA[GitHub Actions Runner] -->|Deploy & Reload| NodeApp
    end

    GitHub[GitHub Repository] -->|Push to main| GHA

Loading

Key Components

• EC2 (Compute): Hosts the application and CI/CD runner.
• Nginx (Gateway): Routes HTTP traffic and maintains WebSocket persistence.
• PM2 (Process Manager): Ensures application uptime and restarts.
• GitHub Actions Runner: Handles automated deployments directly on EC2.

---

🚀 CI/CD Pipeline (Automated Deployment)

A self-hosted GitHub Actions runner is used instead of SSH-based deployments.

Deployment Flow

1. Trigger: Code pushed to the main branch.
2. Pull: EC2-based runner pulls the latest changes.
3. Install: Dependencies installed via npm install.
4. Secrets Injection: Environment variables injected securely.
5. Zero-Downtime Reload: Application reloaded using pm2 reload.

PM2 reloads processes gracefully, ensuring existing WebSocket connections are not abruptly terminated.

---

🛡 Security Design

Security was implemented as a design-first principle.

Key Decisions

• Nginx Reverse Proxy:
  • Node.js app is never exposed directly.
  • Handles HTTP and WebSocket traffic securely.
• AWS Security Groups:
  • Port 80 (HTTP): Open to the public.
  • Port 22 (SSH): Restricted to a single trusted IP.
  • All other ports: Blocked by default.
• Secrets Management:
  • No credentials stored in code.
  • All secrets injected via environment variables.

---

⚙️ Failure Handling & Resilience

To ensure high availability:

• PM2 Process Management:
  • Runs the app as a background daemon.
  • Automatically restarts on crashes.
  • Configured to start on system reboot (pm2 startup).
• Automated Recovery:
  • CI/CD pipeline resolves dependency mismatches.
  • Infrastructure survives EC2 restarts without manual intervention.

---

💰 Cost Estimate (Approximate)

Designed to stay Free Tier eligible for new AWS accounts.

Service	Type	Estimated Cost
Compute	EC2 (t2.micro / t3.micro)	Free Tier or ~$8.50/month
Storage	EBS (gp2/gp3, ≤30GB)	Free Tier
Traffic	Data Transfer Out	< $1/month
CI/CD	GitHub Actions Runner	Included (EC2-based)
Total		~₹0 – ₹800 / month

---

🛠 Tech Stack

• Cloud: AWS (EC2, Security Groups)
• OS: Amazon Linux
• Web Server: Nginx
• Process Manager: PM2
• CI/CD: GitHub Actions (Self-Hosted)
• Backend: Node.js, Socket.io
• Database: MongoDB

---

👨‍💻 Author

Ayush Ranjan DevOps / Cloud Engineering Enthusiast 🔗 LinkedIn Profile 📂 GitHub Profile