<p>I initialized the master node and add 2 worker nodes, but only master and one of the worker node show up when I run the following command:</p>

<pre><code>kubectl get nodes
</code></pre>

<p>also, both these nodes are in 'Not Ready' state. 
What are the steps should I take to understand what the problem could be?</p>

<ul>
<li>I can ping all the nodes from each of the other nodes. </li>
<li>The version of Kubernetes is 1.8.</li>
<li>OS is Cent OS 7</li>
<li><p>I used the following repo to install Kubernetes:</p>

<pre><code>cat &lt;&lt;EOF &gt; /etc/yum.repos.d/kubernetes.repo
[kubernetes] name=Kubernetes
baseurl=http://yum.kubernetes.io/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=0
repo_gpgcheck=0
EOF

yum install kubelet kubeadm kubectl kubernetes-cni
</code></pre></li>
</ul>

<p>First, describe nodes and see if it reports anything:</p>

<p><code>$ kubectl describe nodes</code></p>

<p>Look for conditions, capacity and allocatable:</p>

<pre><code>Conditions:
  Type              Status
  ----              ------
  OutOfDisk         False
  MemoryPressure    False
  DiskPressure      False
  Ready             True
Capacity:
 cpu:       2
 memory:    2052588Ki
 pods:      110
Allocatable:
 cpu:       2
 memory:    1950188Ki
 pods:      110
</code></pre>

<p>If everything is alright here, SSH into the node and observe <code>kubelet</code> logs to see if it reports anything. Like certificate erros, authentication errors etc.</p>

<p>If <code>kubelet</code> is running as a systemd service, you can use</p>

<p><code>$ journalctl -u kubelet</code></p>
