Kube-probe HTTP probe failed with status code 502

What is Kube-probe HTTP probe failed with status code 502

Understanding Kube-probe

Kube-probe is a diagnostic tool used in Kubernetes to monitor the health of applications running in a cluster. It helps ensure that applications are running smoothly by performing health checks and reporting any issues. Kube-probe can perform HTTP, TCP, and command-based checks to determine the status of an application.

Identifying the Symptom

When using Kube-probe, you might encounter an error message stating: HTTP probe failed with status code 502. This indicates that the probe attempted to connect to an application endpoint but received a 502 Bad Gateway response.

Understanding the 502 Error Code

What is a 502 Bad Gateway?

The 502 status code means that the application, acting as a gateway or proxy, received an invalid response from an upstream server. This typically occurs when the upstream server is down, misconfigured, or unable to handle the request.

Common Causes of 502 Errors

Upstream server is unavailable or down. Network connectivity issues between the proxy and upstream server. Misconfigured proxy settings.

Steps to Resolve the Issue

1. Investigate the Upstream Server

Start by checking the status of the upstream server. Ensure it is running and capable of handling requests. You can use the following command to check the status of a service in Kubernetes:

kubectl get pods -l app=your-upstream-app

Replace your-upstream-app with the label of your upstream application.

2. Check Network Connectivity

Ensure that there are no network issues preventing the proxy from communicating with the upstream server. You can test connectivity using:

kubectl exec -it your-proxy-pod -- ping your-upstream-service

Replace your-proxy-pod and your-upstream-service with the appropriate pod and service names.

3. Review Proxy Configuration

Check the configuration of the proxy to ensure it is correctly set up to forward requests to the upstream server. Look for any misconfigurations in the proxy settings.

Additional Resources

For more information on troubleshooting Kubernetes applications, you can refer to the following resources:

Kubernetes Debugging Services Kubernetes Services