title: Nginx ingress: upstream connection timeout (Operation timed out)
body: <p>I have configured nginx-ingress for UDP load balancing. Below is my configuration in helm chart.</p>
  <pre><code>udp: {
         &quot;514&quot;:&quot;default/syslog-service:514&quot;,
         &quot;162&quot;:&quot;default/trapreceiver-service:162&quot;,
         &quot;123&quot;:&quot;default/ntp-service:123&quot;
  }
  </code></pre>
  <p>And my configmap</p>
  <pre><code>data:
    max-worker-connections: &quot;65535&quot;
    proxy-body-size: 500m
    proxy-connect-timeout: &quot;50&quot;
    proxy-next-upstream-tries: &quot;2&quot;
    proxy-read-timeout: &quot;3600&quot;
    proxy-send-timeout: &quot;120&quot;
  </code></pre>
  <p>Ingress is not able to send UDP packets to backend due to below error</p>
  <pre><code>[1000::601] [09/Nov/2020:17:19:57 +0000] UDP 502 0 48 600.000
  [1000::601] [09/Nov/2020:17:19:57 +0000] UDP 502 0 48 600.001
  2020/11/09 17:19:57 [error] 1166#1166: *868219 upstream timed out (110: Operation timed out) while proxying connection, udp client: 1000::601, server: [::]:123, upstream: &quot;[fc00::fcc1]:123&quot;, bytes from/to client:48/0, bytes from/to upstream:0/48
  [1000::601] [09/Nov/2020:17:19:57 +0000] UDP 502 0 387 600.001
  2020/11/09 17:19:57 [error] 1166#1166: *868221 upstream timed out (110: Operation timed out) while proxying connection, udp client: 1000::601, server: [::]:162, upstream: &quot;[fc00::696e]:162&quot;, bytes from/to client:387/0, bytes from/to upstream:0/387
  
  </code></pre>