Kubernetes : Configure Worker Node2023/10/19

Configure Multi Nodes Kubernetes Cluster.

This example is based on the environment like follows.

+----------------------+   +----------------------+
|   [ mgr.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]	Configure pre-requirements on all Nodes, refer to here.
[2]	Join in Kubernetes Cluster which is initialized on Control Plane Node. The command for joining is just the one [kubeadm join ***] which was shown on the bottom of the results on initial setup of Cluster.

# if Firewalld is running, disable it

[root@node01 ~]#

systemctl disable --now firewalld

[root@node01 ~]#

kubeadm join 10.0.0.25:6443 --token yq90qu.cl827hpp06az8isd \
--discovery-token-ca-cert-hash sha256:8a8bd725c9cbf8d03c0a724bded0afb923a067d48ca50fd8f0346fd3d0a27b6e

[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-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.

# OK if [This node has joined the cluster]

[3]	Verify Status on Manager Node or Client Hosts you did setup cluster admin file. That's Ok if all STATUS are Ready.

[root@mgr ~]#

kubectl get nodes

NAME               STATUS   ROLES           AGE    VERSION
dlp.srv.world      Ready    control-plane   65m    v1.28.2
node01.srv.world   Ready    <none>          2m1s   v1.28.2
node02.srv.world   Ready    <none>          28s    v1.28.2

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