.png){kind=small}
What You Will Learn
Intermediate
- The control plane components
- Worker node components
- How they communicate
Kubernetes cluster: Control Plane manages Worker Nodes, which run Pods
Control Plane (Master Node)
The control plane makes global decisions and manages the cluster. It has 4 components:
| Component | What it does |
|---|---|
| API Server | Entry point for all K8s commands (kubectl talks to this) |
| etcd | Key-value store - the brain of the cluster (stores all state) |
| Scheduler | Decides which node runs each Pod |
| Controller Manager | Runs reconciliation loops (keeps desired state = actual state) |
Worker Nodes
Worker nodes run your application Pods. Each node has 3 components:
| Component | What it does |
|---|---|
| kubelet | Agent that manages Pods on the node. Talks to API server. |
| kube-proxy | Manages network rules and load balancing |
| Container Runtime | Runs containers (containerd, CRI-O, Docker) |
How they communicate
kubectl -> API Server -> etcd (stores state) -> Scheduler (assigns Pods) -> kubelet (on worker node runs the Pod) -> container runtime (runs containers).Practical Exercise
Run: kubectl get nodes - see your worker node
Run: kubectl cluster-info - see control plane URL
Run: minikube ssh - SSH into the node
Inside: docker ps - see K8s components running as containers
Key Takeaways
- Control Plane: API Server, etcd, Scheduler, Controller Manager.
- Worker Nodes: kubelet, kube-proxy, container runtime.
- API Server is the entry point - all commands go through it.
- etcd stores ALL cluster state (the source of truth).
- Scheduler decides which node runs each Pod.
Comments
Comments
Post a Comment