<p>Getting the below mentioned error while trying to connect to cluster from worker node.</p>

<p>Cluster version is <code>1.10.4</code> and node version is <code>1.11.0</code></p>

<pre><code>[discovery] Successfully established connection with API Server "10.148.0.2:6443"
[kubelet] Downloading configuration for the kubelet from the "kubelet-config-1.11" ConfigMap in the kube-system namespace
configmaps "kubelet-config-1.11" is forbidden: User "system:bootstrap:7fho7b" cannot get configmaps in the namespace "kube-system"
</code></pre>

<p>Definitely check your version of kubeadm and kubelet, make sure the same version of these packages is used along all of your nodes.  Prior to installing, you should "mark and hold" your versions of these on your hosts:</p>

<h3>check your current version of each:</h3>

<p>kubelet --version</p>

<h3>check kubeadm</h3>

<p>kubeadm version</p>

<h3>if they're different, you've got problems.   You should reinstall the same version among all your nodes and allow downgrades.  My versions in the command below are probably older than what is currently out, you can replace the version number with some more up to date, but this will work:</h3>

<p>sudo apt-get install -y docker-ce=18.06.1~ce~3-0~ubuntu kubelet=1.12.2-00 kubeadm=1.12.2-00 kubectl=1.12.2-00 --allow-downgrades</p>

<h3>then, once they're installed, mark and hold them so they can't be upgraded automatically, and break your system</h3>

<p>sudo apt-mark hold docker-ce kubelet kubeadm kubectl</p>
