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Kubernetes : Add Worker Nodes2025/05/20

 

Add new Worker Nodes to existing Kubernetes Cluster.

This example is based on the cluster environment like follows.
It adds [node03.srv.world (10.0.0.53)] as Worker Node to this cluster.

+----------------------+   +----------------------+
|  [ ctrl.srv.world ]  |   |   [ dlp.srv.world ]  |
|     Manager Node     |   |     Control Plane    |
+-----------+----------+   +-----------+----------+
        eth0|10.0.0.25             eth0|10.0.0.30
            |                          |
------------+--------------------------+-----------
            |                          |
        eth0|10.0.0.51             eth0|10.0.0.52
+-----------+----------+   +-----------+----------+
| [ node01.srv.world ] |   | [ node02.srv.world ] |
|     Worker Node#1    |   |     Worker Node#2    |
+----------------------+   +----------------------+

[1]

On a new Node, Configure common settings to join in Cluster, refer to here.

[2] Confirm join command on Control Plane Node.
[root@dlp ~]#
kubeadm token create --print-join-command

kubeadm join 10.0.0.25:6443 --token 0ocigo.5qnqgk0l36pjuhgq --discovery-token-ca-cert-hash sha256:f7ed0f751e3370eb32367ee7b38ec48c5e48a997ca6935045b573c3b57df5b3e
[3] Run join command on a new Node.
[root@node03 ~]#
kubeadm join 10.0.0.25:6443 --token 0ocigo.5qnqgk0l36pjuhgq \
--discovery-token-ca-cert-hash sha256:f7ed0f751e3370eb32367ee7b38ec48c5e48a997ca6935045b573c3b57df5b3e

[preflight] Running pre-flight checks
[preflight] Reading configuration from the cluster...
[preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml'
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Starting the kubelet
[kubelet-check] Waiting for a healthy kubelet at http://127.0.0.1:10248/healthz. This can take up to 4m0s
[kubelet-check] The kubelet is healthy after 11.002305353s
[kubelet-start] Waiting for the kubelet to perform the TLS Bootstrap

This node has joined the cluster:
* Certificate signing request was sent to apiserver and a response was received.
* The Kubelet was informed of the new secure connection details.

Run 'kubectl get nodes' on the control-plane to see this node join the cluster.
[4] Verify settings on Manager Node. That's OK if the status of new Node turns to [STATUS = Ready].
[root@ctrl ~]#
kubectl get nodes

NAME               STATUS   ROLES           AGE    VERSION
dlp-1.srv.world    Ready    control-plane   117m   v1.31.9
dlp.srv.world      Ready    control-plane   3h3m   v1.31.9
node01.srv.world   Ready    <none>          178m   v1.31.9
node02.srv.world   Ready    <none>          177m   v1.31.9
node03.srv.world   Ready    <none>          38s    v1.31.9

[root@ctrl ~]#
kubectl get pods -A -o wide | grep node03

kube-system            calico-node-5xs5m                                      1/1     Running   0          83s    10.0.0.53         node03.srv.world   <none>           <none>
kube-system            kube-proxy-bv5f2                                       1/1     Running   0          83s    10.0.0.53         node03.srv.world   <none>           <none>
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