Not able to establish connectivity from App Gateway to Cluster Services

Hello Yogesh Bansal,

Welcome to the Microsoft Q&A and thank you for posting your questions here.

Problem

I understand that you are having the "Bad Gateway" error to establish connectivity from App Gateway to Cluster Services.

Solution

To resolve the "Bad Gateway" error you will need to ensure the health of your services through the Azure Application Gateway. Also, this is generic, first you will need to check your configurations and I provides a checklist to help ensure you have covered all necessary configurations.

• NSG rules allow traffic on the necessary ports.
• Correct IP addresses and ports in backend pool.
• Proper protocol in backend settings.
• Correctly configured health probes.
• Proper DNS resolution and Host headers.
• Logs enabled and reviewed for Application Gateway.

Therefore, to troubleshoot these issues you will need to follow the lists below and use the link for more detailed steps:

1. Verify NSG Rules: https://docs.microsoft.com/en-us/azure/virtual-network/network-security-groups-overview and https://docs.microsoft.com/en-us/cli/azure/network/nsg/rule
2. Check Backend Health: https://docs.microsoft.com/en-us/azure/application-gateway/application-gateway-diagnostics#backend-health-and-diagnostics and https://docs.microsoft.com/en-us/cli/azure/network/application-gateway#az_network_application_gateway_show_backend_health
3. Verify Backend Pool Configuration: https://docs.microsoft.com/en-us/azure/application-gateway/configure-web-app-backend-pool and https://docs.microsoft.com/en-us/cli/azure/network/application-gateway/address-pool
4. Review Backend Settings: https://docs.microsoft.com/en-us/azure/application-gateway/application-gateway-http-settings and https://docs.microsoft.com/en-us/cli/azure/network/application-gateway/http-settings
5. Check Probes Configuration: https://docs.microsoft.com/en-us/azure/application-gateway/application-gateway-probe-overview and https://docs.microsoft.com/en-us/cli/azure/network/application-gateway/probe
6. Inspect Application Gateway Logs: https://docs.microsoft.com/en-us/azure/application-gateway/application-gateway-diagnostics#application-gateway-logs and https://docs.microsoft.com/en-us/cli/azure/monitor/diagnostic-settings
7. DNS and Host Header: (https://docs.microsoft.com/en-us/azure/application-gateway/tutorial-url-route and https://docs.microsoft.com/en-us/cli/azure/network/application-gateway/http-settings
8. Test Direct Access to PODs: https://www.gnu.org/software/wget/manual/wget.html
9. Check AKS Network Policies: https://docs.microsoft.com/en-us/azure/aks/use-network-policies

Accept Answer

I hope this is helpful! Do not hesitate to let me know if you have any other questions.

** Please don't forget to close up the thread here by upvoting and accept it as an answer if it is helpful ** so that others in the community facing similar issues can easily find the solution.

Best Regards,

Sina Salam