Ubuntu 26.04

Kubernetes : Add Worker Nodes2026/05/13

 

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 69ih26.wpyfgw7htrgk2n14 --discovery-token-ca-cert-hash sha256:89e79c33d19a21e2a6f7ed22dd1dc0f9ef3660efaeefed636f33e8559f2b26ac
[3] Run join command on a new Node.
root@node03:~#
kubeadm join 10.0.0.25:6443 --token 69ih26.wpyfgw7htrgk2n14 \
--discovery-token-ca-cert-hash sha256:89e79c33d19a21e2a6f7ed22dd1dc0f9ef3660efaeefed636f33e8559f2b26ac

[preflight] Running pre-flight checks
[preflight] Reading configuration from the "kubeadm-config" ConfigMap in namespace "kube-system"...
[preflight] Use 'kubeadm init phase upload-config kubeadm --config your-config-file' to re-upload it.
W0513 01:13:24.949594    2776 utils.go:69] The recommended value for "bindAddress" in "KubeProxyConfiguration" is: ::; the provided value is: 0.0.0.0
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/instance-config.yaml"
[patches] Applied patch of type "application/strategic-merge-patch+json" to target "kubeletconfiguration"
[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 501.811535ms
[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   8m55s   v1.36.0
dlp.srv.world      Ready    control-plane   21h     v1.36.0
node01.srv.world   Ready    <none>          20h     v1.36.0
node02.srv.world   Ready    <none>          20h     v1.36.0
node03.srv.world   Ready    <none>          35s     v1.36.0

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

calico-system     calico-node-5qkns                          1/1     Running   0             91s     10.0.0.53         node03.srv.world   <none>           <none>
calico-system     calico-typha-5ccddc7d97-mh4t9              1/1     Running   0             91s     10.0.0.53         node03.srv.world   <none>           <none>
calico-system     csi-node-driver-r4ksr                      2/2     Running   0             91s     192.168.127.65    node03.srv.world   <none>           <none>
kube-system       kube-proxy-svzmk                           1/1     Running   0             91s     10.0.0.53         node03.srv.world   <none>           <none>
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