<p>Recently I've updated Apache Ignite running in my .Net Core 3.1 application from 2.7.5 to 2.8.1 and today I noticed thousands of warnings like this in the log</p>

<pre><code>Jun 03 18:26:54 quote-service-us-deployment-5d874d8546-psbcs org.apache.ignite.internal.processors.odbc.ClientListenerNioListener: Site: WARN - Unable to perform handshake within timeout [timeout=10000, remoteAddr=/10.250.0.4:57941]
Jun 03 18:26:59 quote-service-uk-deployment-d644cbc86-7xcvw org.apache.ignite.internal.processors.odbc.ClientListenerNioListener: Site: WARN - Unable to perform handshake within timeout [timeout=10000, remoteAddr=/10.250.0.4:57982]
Jun 03 18:26:59 quote-service-us-deployment-5d874d8546-psbcs org.apache.ignite.internal.processors.odbc.ClientListenerNioListener: Site: WARN - Unable to perform handshake within timeout [timeout=10000, remoteAddr=/10.250.0.4:57985]
Jun 03 18:27:04 quote-service-uk-deployment-d644cbc86-7xcvw org.apache.ignite.internal.processors.odbc.ClientListenerNioListener: Site: WARN - Unable to perform handshake within timeout [timeout=10000, remoteAddr=/10.250.0.4:58050]
Jun 03 18:27:04 quote-service-us-deployment-5d874d8546-psbcs org.apache.ignite.internal.processors.odbc.ClientListenerNioListener: Site: WARN - Unable to perform handshake within timeout [timeout=10000, remoteAddr=/10.250.0.4:58051]
Jun 03 18:27:09 quote-service-uk-deployment-d644cbc86-7xcvw org.apache.ignite.internal.processors.odbc.ClientListenerNioListener: Site: WARN - Unable to perform handshake within timeout [timeout=10000, remoteAddr=/10.250.0.4:58114]
Jun 03 18:27:09 quote-service-us-deployment-5d874d8546-psbcs org.apache.ignite.internal.processors.odbc.ClientListenerNioListener: Site: WARN - Unable to perform handshake within timeout [timeout=10000, remoteAddr=/10.250.0.4:58118] 
</code></pre>

<p>I don't use ODBC or JDBC directly in my app and the app is running in a Kubernetes cluster in a virtual network. <em>Interestingly, in all cases the IP on the other end of connection (10.250.0.4 in this case) belongs to the kube-proxy pod.</em> I am a bit perplexed by this. </p>

<p>UPD: 
The same IP address is reported to belong also to the following pods: 
azure-ip-masq-agent and azure-cni-networkmonitor
(I guess those belong to Azure Kubernetes Services that I use to run the K8s cluster)</p>

<p>So it is possible that the network monitor is attempting to reach the ODBC port (just guessing). Is there any opportunity to suppress that warning or disable ODBC connections at all? I don't use ODBC but I'd like to keep the JDBC connections enabled as I occasionally connect to the Ignite instances using DBeaver. Thank you!</p>

<p>If you've defined a service and opened port 10800 then K8 will perform a health check through kube-proxy. This causes Ignite to receive an incomplete handshake on that port log the "unable to perform handshake" message.</p>

<p>ClientListenerNioListener: Site: WARN - Unable to perform handshake within timeout 
[timeout=10000, remoteAddr=/10.250.0.4:58050]</p>

<p>Here the client connector listener(ClientListenerNioListener) is saying that it was not able to establish a successful handshake within 10 seconds to remoteAddr=/10.250.0.4:58050</p>

<p>config client connector: <a href="https://apacheignite.readme.io/docs/binary-client-protocol#connectivity" rel="nofollow noreferrer">https://apacheignite.readme.io/docs/binary-client-protocol#connectivity</a><br>
client connector handshake: <a href="https://apacheignite.readme.io/docs/binary-client-protocol#connection-handshake" rel="nofollow noreferrer">https://apacheignite.readme.io/docs/binary-client-protocol#connection-handshake</a><br>
&nbsp;<br>
&nbsp; </p>

<p>example of service w/port 10800 opened:</p>

<pre><code>kind: Service
metadata: 
  # The name must be equal to TcpDiscoveryKubernetesIpFinder.serviceName
  name: ignite
  # The name must be equal to TcpDiscoveryKubernetesIpFinder.namespaceName
  namespace: ignite
spec:
  type: LoadBalancer
  ports:
    - name: rest
      port: 8080
      targetPort: 8080
    - name: sql
      port: 10800
      targetPort: 10800
</code></pre>

<p>You can redefine the service to not open the port or update the service definition to 
use different ports for the healthcheck:
<a href="https://kubernetes.io/docs/tasks/access-application-cluster/create-external-load-balancer/#preserving-the-client-source-ip" rel="nofollow noreferrer">https://kubernetes.io/docs/tasks/access-application-cluster/create-external-load-balancer/#preserving-the-client-source-ip</a></p>

<p>from the doc:<br>
service.spec.healthCheckNodePort - specifies the health check node port (numeric port number) for the service. If healthCheckNodePort isn’t specified, the service controller allocates a port from your cluster’s NodePort range. You can configure that range by setting an API server command line option, --service-node-port-range. It will use the user-specified healthCheckNodePort value if specified by the client. It only has an effect when type is set to LoadBalancer and externalTrafficPolicy is set to Local.</p>
