Architecture & Control Plane
A Kubernetes cluster consists of two main parts: the Control Plane (master nodes that make global cluster decisions) and Worker Nodes (servers that run container workloads).
1. Control Plane Components (Master Nodes)
| Component | Role & Description |
|---|---|
kube-apiserver | The central front-end API gateway. Every `kubectl` request communicates with the API Server. |
etcd | Consistent, highly-available key-value database storing the entire cluster state & configuration. |
kube-scheduler | Assigns newly created Pods to healthy Worker Nodes based on resource availability and affinity rules. |
kube-controller-manager | Runs background controllers (Node Controller, ReplicaSet Controller, Endpoint Controller) to maintain desired state. |
2. Worker Node Components
| Component | Role & Description |
|---|---|
kubelet | The primary node agent. Ensures container spec descriptions are running and healthy inside Pods. |
kube-proxy | Maintains network routing rules on each node, handling Service IP traffic distribution. |
Container Runtime | The underlying engine that executes containers (containerd, CRI-O, Docker Engine via cri-dockerd). |
Next Up
Learn how to install local Kubernetes clusters: Minikube, Kind (Kubernetes in Docker), K3s, and kubectl setup.
Next Lesson: Cluster Setup & kubectl →
