Nginx Ingress returns only a few metrics on Kuberntes.

#nginx #kubernetes #prometheus

Situation

To visualize http requests on grafana, I installed Nginx Ingress and Prometheus in Kubernetes Cluster (RKE2). The installation steps are based on official guide as follows.

https://kubernetes.github.io/ingress-nginx/

The similar problem is reported on GitHub.

https://github.com/kubernetes/ingress-nginx/issues/5755

The figure shows this situation.

Cause

This problem is caused by not specifying the 'host' parameter in yaml for ingress controller.

The metrics server in nginx ingress only return a few metric about the default host * (generally virtual host). Thus, few metrics display on grafana.

Solution

When you create ingress resource, you set 'host' parameter in yaml. Then, you can check the metrics (such as nginx_ingress_controller_requests) in grafana.