<p>I am novice to k8s, so this might be very simple issue for someone with expertise in the k8s.</p>

<p>I am working with two nodes </p>

<ol>
<li>master - 2cpu, 2 GB memory</li>
<li>worker - 1 cpu, 1 GB memory</li>
<li>OS - ubuntu - hashicorp/bionic64</li>
</ol>

<p>I did setup the master node successfully and i can see it is up and running </p>

<pre><code>vagrant@master:~$ kubectl get nodes
NAME     STATUS   ROLES    AGE   VERSION
master   Ready    master   29m   v1.18.2
</code></pre>

<p>Here is token which i have generated </p>

<pre><code>vagrant@master:~$ kubeadm token create --print-join-command
W0419 13:45:52.513532   16403 configset.go:202] WARNING: kubeadm cannot validate component configs for API groups [kubelet.config.k8s.io kubeproxy.config.k8s.io]
kubeadm join 10.0.2.15:6443 --token xuz63z.todnwgijqb3z1vhz     --discovery-token-ca-cert-hash sha256:d4dadda6fa90c94eca1c8dcd3a441af24bb0727ffc45c0c27161ee8f7e883521 
</code></pre>

<p><strong>Issue</strong> - But when i try to join it from the worker node i get</p>

<pre><code>vagrant@worker:~$ sudo kubeadm join 10.0.2.15:6443 --token xuz63z.todnwgijqb3z1vhz     --discovery-token-ca-cert-hash sha256:d4dadda6fa90c94eca1c8dcd3a441af24bb0727ffc45c0c27161ee8f7e883521 
W0419 13:46:17.651819   15987 join.go:346] [preflight] WARNING: JoinControlPane.controlPlane settings will be ignored when control-plane flag is not set.
[preflight] Running pre-flight checks
        [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/
error execution phase preflight: couldn't validate the identity of the API Server: Get https://10.0.2.15:6443/api/v1/namespaces/kube-public/configmaps/cluster-info?timeout=10s: dial tcp 10.0.2.15:6443: connect: connection refused
To see the stack trace of this error execute with --v=5 or higher
</code></pre>

<p>Here are the ports which are occupied </p>

<pre><code>10.0.2.15:2379 
10.0.2.15:2380 
10.0.2.15:68
</code></pre>

<p>Note i am using CNI from - </p>

<pre><code>kubectl apply -f https://docs.projectcalico.org/manifests/calico.yaml
</code></pre>

<p>It worked for me using this <strong>--apiserver-advertise-address</strong>:</p>
<p><code>sudo kubeadm init  --apiserver-advertise-address=172.16.28.10 --pod-network-cidr=192.168.0.0/16</code></p>
<p><code>kubectl apply -f https://docs.projectcalico.org/v3.8/manifests/calico.yaml</code></p>
<p>I have used calico and worked for me.</p>
<p>In Member node for join:</p>
<p><code>kubeadm join 172.16.28.10:6443 --token 2jm9hd.o2gulx4x1b8l1t5d \ --discovery-token-ca-cert-hash sha256:b8b679e86c4d228bfa486086f18dcac4760e5871e8dd023ec166acfd93781595</code></p>
