Nginx Ingress Controller Returns 404 for path other than '/' AKS - Kubernetes 1.17

Your defined route is /health not /api/health.

The path you define in your Ingress, must be handled by your back-end server.

Your Ingress sends all your requests prefixed with /api to your service backend-webapi, but it doesn't discard the path /api from the route itself.

So, when you send request to http://ingress-domain.westeurope.cloudapp.azure.com.westeurope.cloudapp.azure.com/api/health, your service must handle /api/health not /health.

By default nginx sends traffic to whatever is mentioned in path.You can use rewrite-target annotation to specify target URI where the traffic must be redirected.

# singlebackend-ingress-rule.yamlapiVersion: networking.k8s.io/v1beta1 #  AKS is with 1.17, and supports only apiVersion: networking.k8s.io/v1beta1kind: Ingressmetadata:  name: ingress-rules  annotations:    nginx.ingress.kubernetes.io/rewrite-target: /spec:  rules:  - host: ingress-domain.westeurope.cloudapp.azure.com    http:            paths:      - backend:          serviceName: backend-webapi          servicePort: 80        path: /api

As an alternative to rewrite-target you could use app-root annotation

# singlebackend-ingress-rule.yamlapiVersion: networking.k8s.io/v1beta1 #  AKS is with 1.17, and supports only apiVersion: networking.k8s.io/v1beta1kind: Ingressmetadata:  name: ingress-rules  annotations:    nginx.ingress.kubernetes.io/app-root: /spec:  rules:  - host: ingress-domain.westeurope.cloudapp.azure.com    http:            paths:      - backend:          serviceName: backend-webapi          servicePort: 80        path: /api

With above change below curl should work without needing to have a http handler handling /api/health in the backend. You can simply have a http handler at /health

curl http://ingress-domain.westeurope.cloudapp.azure.com.westeurope.cloudapp.azure.com/health