Cloning and load balancing

Before we dive into specific techniques, it’s important to introduce the concepts of vertical scaling and horizontal scaling.

Vertical scaling means upgrading the hardware that runs your application. This could involve adding more memory, increasing CPU capacity, or improving disk performance. In traditional systems, this is often the first approach, because it allows the application to stay exactly as it is while relying on more powerful machines to handle the increased load. It’s like trying to move more goods with a single vehicle. You might start with a small station wagon, then upgrade to a van, and eventually use a full-size truck. But there’s only so far you can go. Sooner or later, your vehicle becomes too expensive, too heavy, or too large to manage efficiently. That’s when adding more vehicles becomes the better option.

This is where horizontal scaling comes in. Instead of pushing a single machine to its limits...