<p>I'm working on k8s setup with 1 master node and 1 worker node. I'm done with master setup and now I'm trying to joining node to cluster:</p>

<pre><code>sudo kubeadm join master_ip:6443 --token [token] --discovery-token-ca-cert-hash sha256:[key]
</code></pre>

<p>But got this error:</p>

<pre><code>[discovery] Trying to connect to API Server "master_ip:6443"
[discovery] Created cluster-info discovery client, requesting info from "https://master_ip:6443"
[discovery] Failed to request cluster info, will try again: [Get https://master_ip:6443/api/v1/namespaces/kube-public/configmaps/cluster-info: dial tcp master_ip:6443: i/o timeout]
</code></pre>

<p>I use two EC2 instances with CentOS 7 (1 for master and 1 for worker). I'm able to <code>telnet master_ip 6443</code> within the master, but failed within the worker.</p>

<p>What's going wrong here?</p>

Justinus Hermawan
<p>I solved this by setting AWS security group for the port.</p>
