Go ahead. Name a cloud environment that doesn’t include load balancing as the key enabler of elastic scalability. I’ve got coffee… so it’s good, take your time…
Exactly. Load balancing – whether implemented as traditional high availability pairs or clustering – provides the means by which applications (and infrastructure, in many cases) scale horizontally. It is load balancing that is at the heart of elastic scalability models, and that provides a means to ensure availability and even improve performance of applications.
But simple load balancing alone isn’t enough. Too many environments and architectures are wont to toss a simple, network-based solution at the problem and call it a day. But rudimentary load balancing techniques that rely solely on a set of metrics are doomed to fail eventually. That’s because a simple number like «connection count» does not provide enough context to make an intelligent load balancing decision. An application instance may currently have only 100 connections while another has 500, but if the capacity of the former is only 200 while the capacity of the other is 5000, a decision based on «least connections» is not the right one.