Hands-on Lab·Certified Kubernetes Administrator
Control Plane and Node Components
Every diagram of Kubernetes architecture shows five boxes. On a kubeadm cluster four of them are Pods you can list and one is a systemd unit that is not, and knowing which is which decides where you look when something breaks.
Foundations Guide 3 of 103 Beginner
- Kubernetes1.36.4
- Cluster4 nodes
- Runtimecontainerd 2.2.6
- etcd3.6.8
- TimeAbout 30 min
- Reviewed21 August 2026
Written against the versions above. Component flags below are what kubeadm chose. Another installer picks different ones; the components are the same.
| Server Name | IP Address | OS | Roles | CPU | RAM | HDD |
|---|---|---|---|---|---|---|
| CKA1001 | 192.168.0.175 | Ubuntu 26.04 LTS | Control Plane Node | 2 Core | 4 GB | 50 GB |
| CKA1001-NODE01 | 192.168.0.176 | Ubuntu 26.04 LTS | Worker Node | 2 Core | 4 GB | 50 GB |
| CKA1001-NODE02 | 192.168.0.177 | Ubuntu 26.04 LTS | Worker Node | 2 Core | 4 GB | 50 GB |
| CKA1001-NODE03 | 192.168.0.178 | Ubuntu 26.04 LTS | Worker Node | 2 Core | 4 GB | 50 GB |
Before you start
- A kubeadm cluster and
kubectl. Any of the installation guides gets you one. - SSH access to the control plane node with
sudo, for the two commands that read the filesystem. - The kubectl session guide, for
custom-columnsand JSONPath.
-
Four files on disk are the entire control plane
-
Where each component actually runs
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The proof those Pods are not ordinary Pods
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The kubelet is the exception, and that is the important part
-
The runtime below the kubelet
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Read the components' own arguments
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Ask the API server whether it is healthy, and how
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etcd, the one component holding state
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See the scheduler's decisions in the event log