# Node.js Backend Deployment on AWS EC2 ## ✅ STAR Methodology Answer: ### **S - Situation** During my cloud learning journey, I wanted to gain hands-on experience in deploying backend services on cloud infrastructure. I chose to work with a **Node.js application** and deploy it on **AWS EC2**, simulating a real-world production backend deployment scenario. ### **T - Task** My goal was to: * Deploy a simple Node.js backend (REST API). * Host it on an EC2 instance. * Configure networking for external access. * Ensure high availability and proper security. * Test API endpoints using Postman. This project was aimed at understanding the end-to-end flow of cloud-based deployments and managing backend infrastructure. --- ### **A - Action (Detailed Step-by-Step)** #### **1\. Setup the EC2 Instance** * **Launched an EC2 instance** (Amazon Linux 2) via AWS Console. * Chose a **t2.micro instance** under the **Free Tier**, and selected the correct **VPC and subnet**. * Created a **key pair (.pem)** for SSH access. * Opened **port 22 for SSH**, and **port 3000 (or 80/443)** for Node.js app in the **Security Group**. #### **2\. SSH into EC2 & Setup Environment** * Connected to EC2 using: ```plaintext bashCopyEditssh -i "my-key.pem" ec2-user@ ``` * Installed **Node.js and npm**: ```plaintext bashCopyEditsudo yum update -y curl -sL https://rpm.nodesource.com/setup_18.x | sudo bash - sudo yum install -y nodejs ``` #### **3\. Upload Node.js Project to EC2** * Used **Git** to clone the repository or **SCP** to transfer files from local to EC2. ```plaintext bashCopyEditscp -i "my-key.pem" -r ./my-node-app ec2-user@:/home/ec2-user ``` #### **4\. Install Dependencies & Start the Server** * Navigated to the project folder: ```plaintext bashCopyEditcd my-node-app npm install ``` * Started the server: ```plaintext bashCopyEditnode index.js ``` #### **5\. Configure the App to Run in Background (PM2 or nohup)** * Installed PM2: ```plaintext bashCopyEditnpm install -g pm2 pm2 start index.js pm2 startup pm2 save ``` #### **6\. Security Group & Firewall Configuration** * Ensured **inbound rules** allowed traffic to port `3000` or `80`. * Verified `iptables` or `firewalld` settings (if needed). #### **7\. Tested API with Postman** * Verified public IP and tested API routes from Postman. * Confirmed response status codes and payloads. #### **8\. Optional: Custom Domain + Reverse Proxy (Advanced)** * (Optional) Set up **Nginx as a reverse proxy** for production-ready setup. * Linked to a **custom domain using Route 53** (optional learning addition). --- ### **R - Result** * Successfully deployed a **Node.js backend on AWS EC2** with public accessibility. * Gained strong understanding of: * Cloud networking * SSH & Linux setup * Security groups and firewall rules * Backend deployment lifecycle * Validated API functionality using Postman. * Improved confidence in handling real-world backend deployments on cloud. --- ## 👨‍💼 How to Explain in Interview > “I worked on deploying a Node.js backend on AWS EC2 to simulate real-world cloud deployments. I launched and configured the EC2 instance, installed the runtime environment, transferred code, ran the server with PM2, and configured security groups for accessibility. I also tested the endpoints using Postman to ensure proper request/response handling. This gave me hands-on understanding of backend cloud deployments and taught me about cloud infrastructure, networking, and server configuration.” --- ## 💬 10 Follow-Up Questions the Interviewer Might Ask | # | **Question** | **How to Prepare** | | --- | --- | --- | | 1 | Why did you choose EC2 for deployment instead of other services like Lambda or Elastic Beanstalk? | EC2 gives full control over OS, server environment, and setup — ideal for learning infrastructure management. | | 2 | How did you ensure that your backend app keeps running even after the EC2 session ends? | By using PM2 or `nohup` to keep the process alive even after logout. | | 3 | What are the key security practices you followed in this deployment? | Used SSH key authentication, restricted ports in Security Groups, and didn't expose unnecessary services. | | 4 | How would you make this backend deployment production-ready? | Use Nginx as a reverse proxy, HTTPS via SSL (Let’s Encrypt), and auto-restart via PM2. Also, enable monitoring/logging. | | 5 | How can you automate this entire deployment? | By using **Terraform** for infrastructure as code and **Jenkins/GitHub Actions** for CI/CD pipelines. | | 6 | What’s the difference between EC2 and Lambda? | EC2 is IaaS (Infrastructure as a Service), persistent servers. Lambda is FaaS (Function as a Service), event-driven and serverless. | | 7 | How did you test and debug errors during deployment? | Used logs (`console.log`, `pm2 logs`, `journalctl`), curl/Postman, and checked EC2 instance logs for system errors. | | 8 | What are the limitations of using EC2 directly? | Manual setup, scaling is harder, no built-in fault tolerance unless added, and higher overhead compared to managed services. | | 9 | How did you handle app logs and monitoring in this setup? | PM2 provides logs; for production, CloudWatch can be integrated or use file-based logs with logrotate. | | 10 | How would you scale this application to handle more traffic? | Add a Load Balancer (ELB), configure Auto Scaling Groups, or containerize the app with Docker + ECS/EKS. | ## ✅ 5 Challenges Faced & How I Overcame Them --- ### **1\. SSH Connection Error to EC2** **🔸Challenge:** When I first launched the EC2 instance, I was unable to SSH into it. The terminal kept saying "Permission denied" or "Timed out". **🔧 Solution:** * Ensured that the **Security Group** had **port 22 open** for inbound SSH access. * Verified I was using the **correct public IP** and **.pem key file**. * Changed the permissions of the key with: ```plaintext bashCopyEditchmod 400 my-key.pem ``` * Used the right user (`ec2-user`) in the SSH command. **💡 Learning:** Importance of network rules and secure SSH practices. --- ### **2\. Node.js Not Recognized / Installation Issues** **🔸Challenge:** After SSHing into the instance, the `node` and `npm` commands were not recognized. **🔧 Solution:** * Learned that **Amazon Linux 2** does not come with Node.js pre-installed. * Installed it manually using Nodesource: ```plaintext bashCopyEditcurl -sL https://rpm.nodesource.com/setup_18.x | sudo bash - sudo yum install -y nodejs ``` **💡 Learning:** Gained hands-on experience with **package installation** and **dependency management** on Linux. --- ### **3\. Application Stopped After Logout** **🔸Challenge:** The Node.js app would shut down whenever I closed the SSH terminal session. **🔧 Solution:** * Installed **PM2** for better process management and persistence after reboot: ```plaintext bashCopyEditpm2 start index.js pm2 save pm2 startup ``` **💡 Learning:** Understood the importance of **background process managers** like PM2 in real-world deployments. --- ### **4\. API Not Accessible Publicly** **🔸Challenge:** Though the server was running on port 3000, I couldn’t access it from my browser or Postman using the public IP. **🔧 Solution:** * Realized that I needed to **add an inbound rule in the Security Group** for port 3000. * Added rule: * Type: Custom TCP * Port: 3000 * Source: 0.0.0.0/0 (for testing) * Restarted the app and tested successfully. **💡 Learning:** Learned about **AWS networking and security best practices** using security groups and firewalls. --- ### **5\. Application Not Auto-Starting After EC2 Reboot** **🔸Challenge:** Every time I restarted the EC2 instance, the Node.js app wouldn’t start automatically. **🔧 Solution:** * Configured PM2 to generate a startup script: ```plaintext bashCopyEditpm2 startup pm2 save ``` * This ensured that PM2 would **auto-launch all apps on reboot**. **💡 Learning:** Learned about **service persistence and automation** in Linux-based systems. ![](https://cdn.hashnode.com/res/hashnode/image/upload/v1744316492545/44282195-44be-4f5a-9b71-18510080c16c.avif align="center")