The software that runs the cloud started as a Google side project

When you use Netflix, Spotify, or your bank's app, there's a good chance Kubernetes is quietly deciding which computers run the code. Open-sourced by Google in 2014 and now stewarded by the Cloud Native Computing Foundation (CNCF), Kubernetes (nicknamed K8s — 8 letters between the K and the s) is a system for running containerized applications across a fleet of machines.

A container is a lightweight, self-contained bundle of an app and everything it needs to run. Running one is easy; running thousands across hundreds of servers — restarting the ones that crash, scaling up under load, and rolling out new versions without downtime — is the hard part. Kubernetes automates exactly that. You declare the desired state ('I want 10 copies of this service running'), and Kubernetes continuously works to make reality match, rescheduling containers when a machine dies.

The surprising part is its lineage: Kubernetes builds on Borg, an internal Google system that had scheduled production workloads for over a decade before K8s existed. Google effectively handed the industry a distilled version of its own hard-won infrastructure. Today the project has over 125,000 GitHub stars and is one of the most active open-source repositories in the world.