<p>I was facing some issues while joining worker node in existing cluster.
Please find below the details of my scenario.<br>
I've Created a HA clusters with <strong>4 master and 3 worker</strong>.<br>
I removed 1 master node.<br>
Removed node was not a part of cluster now and reset was successful.
Now joining the removed node as worker node in existing cluster.</p>

<p>I'm firing below command</p>

<pre><code>kubeadm join --token giify2.4i6n2jmc7v50c8st 192.168.230.207:6443 --discovery-token-ca-cert-hash sha256:dd431e6e19db45672add3ab0f0b711da29f1894231dbeb10d823ad833b2f6e1b
</code></pre>

<p><em>In above command - 192.168.230.207 is cluster IP</em></p>

<p>Result of above command</p>

<pre><code>[preflight] Running pre-flight checks
    [WARNING Service-Docker]: docker service is not enabled, please run 'systemctl enable docker.service'
    [WARNING IsDockerSystemdCheck]: detected "cgroupfs" as the Docker cgroup driver. The recommended driver is "systemd". Please follow the guide at https://kubernetes.io/docs/setup/cri/
    [WARNING FileExisting-tc]: tc not found in system path
    [WARNING Service-Kubelet]: kubelet service is not enabled, please run 'systemctl enable kubelet.service'
[preflight] Reading configuration from the cluster...
[preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -oyaml'
error execution phase preflight: unable to fetch the kubeadm-config ConfigMap: failed to get config map: Get https://192.168.230.206:6443/api/v1/namespaces/kube-system/configmaps/kubeadm-config: dial tcp 192.168.230.206:6443: connect: connection refused
</code></pre>

<p>Already tried Steps  </p>

<ol>
<li><p>ted this file(<code>kubectl -n kube-system get cm kubeadm-config -o yaml</code>) using kubeadm patch and removed references of removed node("192.168.230.206")  </p></li>
<li><p>We are using external etcd so checked member list to confirm removed node is not a part of etcd now. Fired below command <code>etcdctl --endpoints=https://cluster-ip --ca-file=/etc/etcd/pki/ca.pem --cert-file=/etc/etcd/pki/client.pem --key-file=/etc/etcd/pki/client-key.pem member list</code></p></li>
</ol>

<p>Can someone please help me resolve this issue as I'm not able to join this node?</p>

<p>In addition to @P Ekambaram answer, I assume that you probably have completely dispose of all redundant data from previous <code>kubeadm join</code> setup.</p>

<ol>
<li><p>Remove cluster entries via <code>kubeadm</code> command on worker node: <code>kubeadm reset</code>;</p></li>
<li><p>Wipe all redundant data residing on worker node: <code>rm -rf /etc/kubernetes; rm -rf ~/.kube</code>;</p></li>
<li><p>Try to re-join worker node. </p></li>
</ol>
