Kubernetes (often called K8s) is an open-source container orchestration platform designed to automate the deployment, scaling, and management of containerized applications.
Think of it as the operating system for your cloud/data center that keeps all your containers running properly across many machines.
When you run applications inside containers (like Docker), managing them manually becomes difficult when the number of containers grows. You need to handle:
- How many copies (replicas) of an app should run
- Restarting apps if they crash
- Distributing load across containers
- Updating apps without downtime
- Placing containers on best-fit servers
- Managing storage, configs, secrets
- Auto-scaling based on load
Kubernetes automates all of this above.
Kubernetes is a system that:
- Runs your containers
- Keeps them healthy
- Scales them automatically
- Load-balances traffic
- Handles deployments & rollbacks
- Manages infrastructure resources
| Problem | Without K8s | With K8s |
|---|---|---|
| App crashes | Manual restart | Auto-heals |
| Traffic increase | Manual scaling | Auto-scaling |
| Deployment | Risky, manual process | Rolling updates, rollbacks |
| Load balancing | Manual | Automatic |
| Multi-node deployments | Hard | Built-in |
| Secrets & config | Hard-coded | ConfigMap/Secrets |
| Storage mgmt | Manual | PV/PVC |