<p>I have got a simple pod up and running on my worker node which I am trying to ping from my master node. I'm getting 100% packet loss.</p>
<p><strong>What's working?</strong></p>
<ul>
<li>The worker node itself can be pinged from the master node.</li>
<li>The pod inside the worker node can be pinged from inside of the worker node.</li>
</ul>
<p><strong>What's not working?</strong></p>
<ul>
<li>The master node trying to ping worker node's pod.</li>
</ul>
<p><strong>My take</strong></p>
<p>I think there's a calico misconfiguration that has happened at the master node as the master node doesn't quite understand the IP of the pod.</p>
<p>Results of tracepath to the pod IP</p>
<pre class="lang-sh prettyprint-override"><code>masternode@Master:~$ tracepath 192.168.171.67
 1?: [LOCALHOST]                      pmtu 1440
 1:  no reply
 2:  no reply
 3:  no reply
</code></pre>
<p>Please help.</p>

<p>The Kubernetes pod network is not reachable from the control/data plane nodes.  You can reach any Pod including control plane Pods between each other but not anything on the host.</p>
<p>The quoted Kubernetes Networking fundamentals from the <a href="https://kubernetes.io/docs/concepts/cluster-administration/networking/#the-kubernetes-network-model" rel="nofollow noreferrer">docs</a>:</p>
<ul>
<li>Pods on a node can communicate with all pods on all nodes without NAT</li>
<li>Agents on a node (e.g. system daemons, kubelet) can communicate with all pods on that node. -- Note you can do this with docker for example, but not using the pod network.</li>
</ul>
<p>Also, from the <a href="https://kubernetes.io/docs/concepts/services-networking/" rel="nofollow noreferrer">docs</a>:</p>
<ul>
<li>Containers within a Pod use networking to communicate via loopback.</li>
<li>Cluster networking provides communication between different Pods.</li>
<li>The Service resource lets you expose an application running in Pods to be reachable from outside your cluster.</li>
<li>You can also use Services to publish services only for consumption inside your cluster.</li>
</ul>
