Kubernetes (K8s)

Why Kubernetes Exists

Before Kubernetes, Docker solved the packaging problem. You could put your app in a container and it would run the same everywhere. But when companies started running hundreds or thousands of containers across multiple servers, new problems appeared that Docker alone could not solve. Imagine you have 50 containers running your application across 10 servers. One container crashes — who restarts it? Traffic suddenly doubles — who scales up? You need to deploy a new version — how do you do it without downtime? A server dies — who moves those containers somewhere else? Doing all of this manually is impossible at scale. ``` Problems that appeared at scale: Container crashes -> needs manual restart every time Traffic spike -> manually spin up more containers Server dies -> manually move containers to another server New deployment -> take the app down, update, bring it back Uneven resource use -> some servers idle, some overloaded ``` Kubernetes solves all of this automatically. You tell Kubernetes what you want — "I want 5 copies of this container running, always" — and Kubernetes makes it happen and keeps it that way. ``` Kubernetes features: Self-Healing -> crashed container? K8s restarts it automatically Auto Scaling -> traffic up? K8s adds more containers Rolling Updates -> deploy new version with zero downtime Load Balancing -> distribute traffic across all running containers Resource Management -> decide how much CPU/RAM each container gets Storage Orchestration -> attach storage to containers automatically ``` Kubernetes was originally built by Google, inspired by their internal systems called Borg and Omega. It was released in 2014 and donated to the CNCF (Cloud Native Computing Foundation) in 2015. The name comes from Greek — it means "helmsman" or "pilot". That is why the logo is a ship's wheel. K8s is the abbreviation — K, then 8 letters, then s. ---