When you're building an application, it's tempting to deploy everything onto a single virtual machine. It's simple, inexpensive, and gets you to production quickly. For many startups, that's exactly how things begin.
Imagine FreshCart, a fast-growing online grocery platform. During most of the week, a single server comfortably handles browsing, product searches, and checkout requests. Then the marketing team launches a "Weekend Mega Sale" campaign.
Within minutes, thousands of users visit the site.
Pages begin loading slowly. Checkout requests queue up. CPU utilization reaches nearly 100%, memory becomes exhausted, and eventually the server stops responding. Every customer is trying to access the same machine, and because that machine hosts the application and is directly exposed to the internet, it becomes both the performance bottleneck and the biggest security risk.
This scenario is common because a single exposed VM has several limitations:
