<p>I have installed a kubernetes cluster on <code>Azure</code> with kubespray <code>2.13.2</code>.
But after I have installed some pods of my data platform components,
I have noticed that the pods running on the same node cannot access to each other through service.</p>
<p>For example, my presto coordinator has to access hive metastore.
Let's see the services in my namespace:</p>
<pre><code>kubectl get svc -n ai-developer
NAME                                              TYPE           CLUSTER-IP      EXTERNAL-IP      PORT(S)                      AGE
metastore                                 ClusterIP      10.233.12.66    &lt;none&gt;           9083/TCP                     4h53m
</code></pre>
<p>Hive Metastore service is called <code>metastore</code>, through which my presto coordinator has to access hive metastore pod.
Let's see the following pods in my namespace:</p>
<pre><code>kubectl get po -n ai-developer -o wide
NAME                                          READY   STATUS      RESTARTS   AGE     IP             NODE       NOMINATED NODE   READINESS GATES
metastore-5544f95b6b-cqmkx                    1/1     Running     0          9h      10.233.69.20   minion-3   &lt;none&gt;           &lt;none&gt;
presto-coordinator-796c4c7bcd-7lngs           1/1     Running     0          5h32m   10.233.69.29   minion-3   &lt;none&gt;           &lt;none&gt;
presto-worker-0                               1/1     Running     0          5h32m   10.233.67.52   minion-1   &lt;none&gt;           &lt;none&gt;
presto-worker-1                               1/1     Running     0          5h32m   10.233.70.24   minion-4   &lt;none&gt;           &lt;none&gt;
presto-worker-2                               1/1     Running     0          5h31m   10.233.68.24   minion-2   &lt;none&gt;           &lt;none&gt;
presto-worker-3                               1/1     Running     0          5h31m   10.233.71.27   minion-0   &lt;none&gt;           &lt;none&gt;
</code></pre>
<p>Take a look at that the hive metastore pod <code>metastore-5544f95b6b-cqmkx </code> which is running on the node <code>minion-3</code> on which presto coordinator pod <code>presto-coordinator-796c4c7bcd-7lngs</code> also is running.</p>
<p>I have configured hive metastore url of  <code>thrift://metastore:9083</code>  to hive properties for hive catalog in presto coordinator.
When the presto pods are running on that same node where hive metastore pod is running, they cannot access to my hive metastore, but the pod running on other node where hive metastore is not running can access to the hive metastore through <code>service</code> very well.</p>
<p>I have mentioned just one example, but I have experienced several other cases like this example for now.</p>
<p><code>kubenet</code> is installed as network plugin in my kubernetes cluster installed with kubespray on <code>azure</code>:</p>
<pre><code>/usr/local/bin/kubelet --logtostderr=true --v=2 --node-ip=10.240.0.4 --hostname-override=minion-3 --bootstrap-kubeconfig=/etc/kubernetes/bootstrap-kubelet.conf --config=/etc/kubernetes/kubelet-config.yaml --kubeconfig=/etc/kubernetes/kubelet.conf --pod-infra-container-image=k8s.gcr.io/pause:3.1 --runtime-cgroups=/systemd/system.slice --hairpin-mode=promiscuous-bridge --network-plugin=kubenet --cloud-provider=azure --cloud-config=/etc/kubernetes/cloud_config
</code></pre>
<p>Any idea?</p>

<p>Please check if the iptables Chain FORWARD default policy is ACCEPT .
In my case , set the Forward chain default policy from drop to accept, the communitcation between nodes works well.</p>
