nginx_ingress_controller_request_duration_seconds_count associates request with wrong ingress

[jeanbaptiste-brasselet]

What happened:

I have three ingress using the same host with three path in one namespace like this:

HOST PATH NAMESPACE SERVICE PORT INGRESS example.host.com /public/v1/test1 test service1 80 public-service1 example.host.com /public/v1/test2 test service2 80 public-service2 example.host.com /public/v1/test3 test service3 80 public-service3

For some reason when I look into nginx_ingress_controller_request_duration_seconds_count I see lines like this one :

nginx_ingress_controller_request_duration_seconds_count{container="controller", controller_class="k8s.io/ingress-public", controller_namespace="ingress-controller", controller_pod="ingress-public-ingress-nginx-controller-d5c797b8b-krnst", endpoint="metrics", exported_namespace="test", host="example.host.com, ingress="public-service3", instance="10.56.2.4:10254", job="ingress-public-ingress-nginx-controller-metrics", method="GET", namespace="ingress-controller", path="/", pod="ingress-public-ingress-nginx-controller-d5c797b8b-krnst", service="ingress-public-ingress-nginx-controller-metrics", status="404"}

As you can see it associates a request done on / with public-service3 ingress so when I am trying to do some metrics I got a lot of 404 error reported for this specific ingress when I have none in reality.

I don't really understand why this association exist.

What you expected to happen:

I would have expected the ingress to be null or undefined since this path is not defined anywhere.

[k8s-ci-robot]

@jeanbaptiste-brasselet: This issue is currently awaiting triage.

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[longwuyuan]

There id a metricsbyhost flag somewhere. Please search in docs on the userguide section, monitoring page. Will try to send link later.

Thanks, ; Long

On Thu, 20 Oct, 2022, 8:34 PM Kubernetes Prow Robot, < @.***> wrote:

@jeanbaptiste-brasselet https://github.com/jeanbaptiste-brasselet: This issue is currently awaiting triage.

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The triage/accepted label can be added by org members by writing /triage accepted in a comment.

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[longwuyuan]

/remove-kind bug

You did not say you have a wildcard host but i wonder how this flag https://kubernetes.github.io/ingress-nginx/user-guide/monitoring/#wildcard-ingresses impacts your use case of no /

[jeanbaptiste-brasselet]

I think you misunderstand my issue (Indeed I am not using any wildward). I have metrics for the path / on my hostname. The problem is for some reason it says it belongs to the ingress public-service3 when the only path declared for this ingress is /public/v1/test3.

As a matter of fact I have no ingress that matches the / path that's why it always return 404 and I would have expected to see ingress: '' in the metric not ingress: 'public-service3'

Another information after more testing if I do requests on path that are not in my ingresses like /toto /tata in the end all those thing are added to the path / in the metrics with ingress: 'public-service3' as a value.

Any idea ?

[jeanbaptiste-brasselet]

I think I get what is happening, it seems there is a default backend at the last resort to all the ingress you create and this default backend send back 404.

If I am right I wonder what I can do to have those error not associated with the ingress and it's default backend. Do I need to create a backend for this myself with an ingress ?

[bumarcell]

Create a backend with an svc and configure nginx to use it as a default-backend