<p dir="auto">using 1.2.4</p>
<p dir="auto">I created a pod with a small udp echo server running on port 5005 (mendhak/udp-listener) and exposed it as a udp service.</p>
<p dir="auto"><strong>This only happens when the client and server land on the same node!</strong></p>
<p dir="auto">A simple client</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="nc -4u -w1 $SERVICE_IP 5005 &lt;&lt;&lt; a
nc -4u -w1 $POD_IP 5005 &lt;&lt;&lt; b"><pre class="notranslate"><code class="notranslate">nc -4u -w1 $SERVICE_IP 5005 &lt;&lt;&lt; a
nc -4u -w1 $POD_IP 5005 &lt;&lt;&lt; b
</code></pre></div>
<p dir="auto">Meanwhile, on the server</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="Listening on UDP port 5005
a
a
b"><pre class="notranslate"><code class="notranslate">Listening on UDP port 5005
a
a
b
</code></pre></div>
<p dir="auto">tcpdump on the node</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="08:00:38.574388 IP 10.228.1.5.38130 &gt; 10.228.1.3.5005: UDP, length 7
08:00:38.574447 IP 10.228.1.5.38130 &gt; 10.228.1.3.5005: UDP, length 7
08:00:42.022864 IP 10.228.1.5.42386 &gt; 10.228.1.3.5005: UDP, length 7"><pre class="notranslate"><code class="notranslate">08:00:38.574388 IP 10.228.1.5.38130 &gt; 10.228.1.3.5005: UDP, length 7
08:00:38.574447 IP 10.228.1.5.38130 &gt; 10.228.1.3.5005: UDP, length 7
08:00:42.022864 IP 10.228.1.5.42386 &gt; 10.228.1.3.5005: UDP, length 7
</code></pre></div>
<p dir="auto">By the way, my real use case was using logstash with a udp input and my logs were duplicated sometimes (when the pod that produces logs landed on the same node as logstash).</p>
<p dir="auto">another thought, maybe TCP packets get duplicated too but handled?</p>
<p dir="auto"><strong>Is this a request for help?</strong> (If yes, you should use our troubleshooting guide and community support channels, see <a href="http://kubernetes.io/docs/troubleshooting/" rel="nofollow">http://kubernetes.io/docs/troubleshooting/</a>.):</p>
<p dir="auto"><strong>What keywords did you search in Kubernetes issues before filing this one?</strong> (If you have found any duplicates, you should instead reply there.):</p>
<hr>
<p dir="auto"><strong>Is this a BUG REPORT or FEATURE REQUEST?</strong> (choose one):</p>

<p dir="auto"><strong>Kubernetes version</strong> (use <code class="notranslate">kubectl version</code>):</p>
<p dir="auto"><strong>Environment</strong>:</p>
<ul dir="auto">
<li><strong>Cloud provider or hardware configuration</strong>:</li>
<li><strong>OS</strong> (e.g. from /etc/os-release):</li>
<li><strong>Kernel</strong> (e.g. <code class="notranslate">uname -a</code>):</li>
<li><strong>Install tools</strong>:</li>
<li><strong>Others</strong>:</li>
</ul>
<p dir="auto"><strong>What happened</strong>:</p>
<p dir="auto"><strong>What you expected to happen</strong>:</p>
<p dir="auto"><strong>How to reproduce it</strong> (as minimally and precisely as possible):</p>
<p dir="auto"><strong>Anything else do we need to know</strong>:</p>