Deploying a Full-Stack App on Azure: What I Learned Connecting a VM to a Private MySQL Database

Introduction There's a difference between reading about cloud architecture and actually building it. This week, as part of my DevOps Micro Internship (DMI Cohort 2), I deployed the EpicBook web application on Microsoft Azure — a full-stack app with a React frontend, Node.js backend, and a MySQL database. What made this assignment different from previous ones wasn't just the tools. It was the deliberate security decisions I had to make at every step. This post walks through what I built, the decisions I made, and what actually clicked for me along the way. What I Built A two-tier deployment on Azure: Compute layer: Ubuntu 22.04 VM ( Standard B1s ) running the EpicBook app with Nginx as a reverse proxy Database layer: Azure Database for MySQL Flexible Server, placed in a private subnet with no public internet access The goal was to get the app live and accessible via the VM's public IP, while keeping the database completely hidden from the outside world. Step 1: Designing the Network Bef