<p>I have 2 vms that run a kubernetes master and a slave node that i have setup locally. Till now everything was working fine but suddenly it started giving errors when I try to start the master with kubeadm init command.I have cpppied the error below.</p>

<pre><code>shayeeb@ubuntu:~$ sudo kubeadm init
[init] using Kubernetes version: v1.11.1
[preflight] running pre-flight checks
I0718 11:04:57.038464   20370 kernel_validator.go:81] Validating kernel version
I0718 11:04:57.038896   20370 kernel_validator.go:96] Validating kernel config
[preflight/images] Pulling images required for setting up a Kubernetes cluster
[preflight/images] This might take a minute or two, depending on the speed of your internet connection
[preflight/images] You can also perform this action in beforehand using 'kubeadm config images pull'
[preflight] Some fatal errors occurred:
[ERROR ImagePull]: failed to pull image [k8s.gcr.io/kube-apiserver-amd64:v1.11.1]: exit status 1
[ERROR ImagePull]: failed to pull image [k8s.gcr.io/kube-controller-manager-amd64:v1.11.1]: exit status 1
[ERROR ImagePull]: failed to pull image [k8s.gcr.io/kube-scheduler-amd64:v1.11.1]: exit status 1
[ERROR ImagePull]: failed to pull image [k8s.gcr.io/kube-proxy-amd64:v1.11.1]: exit status 1
[preflight] If you know what you are doing, you can make a check non-fatal with `--ignore-preflight-errors=...`
</code></pre>

<p>You can also run following command rather than writing the yaml,</p>

<pre><code>kubeadm init --kubernetes-version=1.11.0 --apiserver-advertise-address=&lt;public_ip&gt; --apiserver-cert-extra-sans=&lt;private_ip&gt;
</code></pre>

<p>If you are using flannel network run following commad,</p>

<pre><code>kubeadm init --kubernetes-version=1.11.0 --pod-network-cidr=10.244.0.0/16 --apiserver-advertise-address=&lt;public_ip&gt; --apiserver-cert-extra-sans=&lt;internal_ip&gt; 
</code></pre>
