How to resolve the issue of being unable to access NodePort externally in k8s?

If external access is not working when using NodePort type services in Kubernetes, you can try the following solutions: 1. Check firewall rules: Make sure the firewall rules on the Node allow traffic through the NodePort port. For example, on Linux, you can use iptables command or firewalld service to add the appropriate rules. 2. Check network configuration: Ensure that the network configuration of the Kubernetes cluster is correct. If using CNI plugins like Calico or Flannel, check their configuration and network policies. 3. Check NodePort port range: Make sure the NodePort port range does not conflict with other services or processes. Kubernetes default uses ports in the range of 30000-32767. You can modify the default range by changing the –service-node-port-range parameter in kube-apiserver. 4. Check service definition: Ensure that the ports and target ports in the service definition are correct. If the specified target port in the service definition does not match the container’s listening port, external access will not reach the container. 5. Check node labels: If using a Node selector to deploy services on specific nodes, ensure that the nodes have the correct labels and that the service selector matches the node labels. 6. Check network plugin configuration: If using a network plugin (such as Calico or Flannel), ensure that the plugin configuration is correct and that the network policies allow access to NodePort from the outside. 7. Check service status: Use the kubectl get svc command to check the status of the service, make sure the service is running and the external IP is correctly assigned. If the above methods do not resolve the issue, you can troubleshoot further by checking the logs of the Kubernetes cluster for more detailed error information.