unclear documentation about scrapeConfigNamespaceSelector and scrapeConfigSelector

[rptaylor]

What happened?

Description

Steps to Reproduce

Look at https://prometheus-operator.dev/docs/user-guides/scrapeconfig/ , and output of kubectl explain prometheus.spec

Expected Result

It would be clear how to configure scrapeConfigNamespaceSelector and scrapeConfigSelector to match all namespaces/objects or none.

Actual Result

I am left wondering what exactly an "empty label selector" is vs a "null label selector". I tried a variety of things in my Helm values, e.g.

prometheus:
  scrapeConfigNamespaceSelector:
  scrapeConfigSelector:

To me that is what null or None would look like.

prometheus:
  scrapeConfigNamespaceSelector: ""
  scrapeConfigSelector: ""

To me "" corresponds to what "empty" would mean. But according to kubectl -n kube-prometheus get prometheus -o yaml | grep scrapeConf it has exactly the same end result as scrapeConfigNamespaceSelector:, they both get interpreted to {}.

Prometheus Operator Version

Name:                   kube-prometheus-operator
Namespace:              kube-prometheus
CreationTimestamp:      Thu, 14 Dec 2023 22:40:30 +0000
Labels:                 app.kubernetes.io/component=operator
                        app.kubernetes.io/instance=kube-prometheus
                        app.kubernetes.io/managed-by=Helm
                        app.kubernetes.io/name=kube-prometheus
                        app.kubernetes.io/version=0.68.0
                        helm.sh/chart=kube-prometheus-8.21.6
Annotations:            deployment.kubernetes.io/revision: 2
                        meta.helm.sh/release-name: kube-prometheus
                        meta.helm.sh/release-namespace: kube-prometheus
Selector:               app.kubernetes.io/component=operator,app.kubernetes.io/instance=kube-prometheus,app.kubernetes.io/name=kube-prometheus
Replicas:               1 desired | 1 updated | 2 total | 0 available | 2 unavailable
StrategyType:           RollingUpdate
MinReadySeconds:        0
RollingUpdateStrategy:  25% max unavailable, 25% max surge
Pod Template:
  Labels:           app.kubernetes.io/component=operator
                    app.kubernetes.io/instance=kube-prometheus
                    app.kubernetes.io/managed-by=Helm
                    app.kubernetes.io/name=kube-prometheus
                    app.kubernetes.io/version=0.68.0
                    helm.sh/chart=kube-prometheus-8.21.6
  Annotations:      kubectl.kubernetes.io/restartedAt: 2024-03-18T17:40:11Z
  Service Account:  kube-prometheus-operator
  Containers:
   prometheus-operator:
    Image:      docker.io/bitnami/prometheus-operator:0.68.0-debian-11-r27
    Port:       8080/TCP
    Host Port:  0/TCP
    Args:
      --kubelet-service=kube-system/kube-prometheus-kubelet
      --log-format=logfmt
      --log-level=info
      --localhost=127.0.0.1
      --prometheus-config-reloader=$(PROMETHEUS_CONFIG_RELOADER)
    Limits:
      cpu:     500m
      memory:  500Mi
    Requests:
      cpu:      10m
      memory:   50Mi
    Liveness:   http-get http://:http/metrics delay=120s timeout=5s period=10s #success=1 #failure=6
    Readiness:  http-get http://:http/metrics delay=30s timeout=5s period=10s #success=1 #failure=6
    Environment:
      PROMETHEUS_CONFIG_RELOADER:  <set to the key 'prometheus-config-reloader' of config map 'kube-prometheus-operator'>  Optional: false
    Mounts:                        <none>
  Volumes:                         <none>

### Kubernetes Version

```yaml
v1.24.14

Kubernetes Cluster Type

kubeadm

How did you deploy Prometheus-Operator?

Other (please comment)

Manifests

No response

prometheus-operator log output

not relevant for documentation question

Anything else?

using bitnami kube-prometheus chart

[Ayush9026]

/assign @nicolastakashi sir i will solve this issue.

[OtowoSamuel]

@nicolastakashi Can i work on this?

[simonpasquier]

@OtowoSamuel sure, go ahead! Usually claiming your interest in the issue as you did is enough (unless there's an ongoing PR of course but it isn't the case here).