title: How to use kubeadm to create kubernetes cluster?
body: <p>I init k8s cluster master with kubeadm, but I felt very confused. The version of kubeadm:</p>
  
  <pre><code># ./kubeadm version
  kubeadm version: version.Info{Major:"1", Minor:"5", GitVersion:"v1.5.1", GitCommit:"82450d03cb057bab0950214ef122b67c83fb11df", GitTreeState:"clean", BuildDate:"2016-12-14T00:52:01Z", GoVersion:"go1.7.4", Compiler:"gc", Platform:"linux/amd64"}
  </code></pre>
  
  <p>When I run command with <code>kubeadm init</code>, told me must start kubelet.service:</p>
  
  <pre><code># ./kubeadm init
  Running pre-flight checks
  preflight check errors:
      kubelet service is not active, please run 'systemctl start kubelet.service'
  </code></pre>
  
  <p>And then When I retry this command after <code>systemctl restart kubelet.service</code>, told me <code>Port 10250 in use</code>:</p>
  
  <pre><code># systemctl restart kubelet.service
  # ./kubeadm init
  Running pre-flight checks
  preflight check errors:
      Port 10250 is in use
      /var/lib/kubelet is not empty
  </code></pre>
  
  <p>Is there any way to run kubelet with no port OR can I change the port of kubelet?</p>