Nodes in Kubernetes: The Unsung Heroes of Container Orchestration

What is a Node in Kubernetes?

A Node is a worker machine in Kubernetes. It can be a physical server or a virtual machine in the cloud. Nodes are where your pods (and therefore your containers) actually run.

Think of it like this:

Cluster = a team of machines.

Node = one machine in that team.

Pod = a unit of work scheduled onto a node.

Container = the actual application process inside the pod.

🔹 Node Components

Each node runs several critical services:

Kubelet → Agent that talks to the control plane and ensures pods are running.

Container Runtime → Runs containers (Docker, containerd, CRI‑O).

Kube‑proxy → Manages networking rules so pods can communicate with each other and with services.

🔹 Types of Nodes

Control Plane Node → Runs cluster management components (API server, etcd, scheduler, controller manager).

Worker Node → Runs user workloads (pods and containers).

🔹 Example: Checking Nodes

When you run:

[root@centosmqm ~]# kubectl get nodes

NAME        STATUS   ROLES           AGE   VERSION

centosmqm   Ready    control-plane   28h   v1.30.14

Explanation of Output:

NAME → centosmqm → the hostname of your node.

STATUS → Ready → the node is healthy and can accept pods.

ROLES → control-plane → this node is acting as the master/control plane, not a worker.

AGE → 28h → the node has been part of the cluster for 28 hours.

VERSION → v1.30.14 → the Kubernetes version running on this node.

👉 In this example, your cluster currently has one node (centosmqm), and it is the control plane node. If you added worker nodes, they would also appear in this list with roles like <none> or worker.

🔹 Commands to Work with Nodes

# List all nodes

kubectl get nodes

# Detailed info about a node

kubectl describe node centosmqm

# Show nodes with more details (IP, OS, version)

kubectl get nodes -o wide

✅ Summary

A Node is the machine (VM or physical) that runs pods.

Nodes can be control plane (managing the cluster) or worker nodes (running workloads).

Your example shows a single control-plane node named centosmqm, which is healthy and running Kubernetes v1.30.14.