grafana dashboard display no data about version-checker HOT 14 CLOSED

root@node1:/opt# k get ep -n  monitoring -l app=version-checker
NAME              ENDPOINTS           AGE
version-checker   172.20.2.171:8080   4m5s
root@node1:/opt# curl http://172.20.2.171:8080/metrics
# HELP version_checker_is_latest_version Where the container in use is using the latest upstream registry version
# TYPE version_checker_is_latest_version gauge
version_checker_is_latest_version{container="alertmanager",current_version="v0.20.0",image="quay.io/prometheus/alertmanager",latest_version="v0.21.0",namespace="monitoring",pod="alertmanager-prom-prometheus-operator-alertmanager-0"} 0
version_checker_is_latest_version{container="autoscaler",current_version="1.6.0",image="gcr.io/google-containers/cluster-proportional-autoscaler-amd64",latest_version="1.8.1",namespace="kube-system",pod="dns-autoscaler-79599df498-cqxvx"} 0
version_checker_is_latest_version{container="cilium-agent",current_version="v1.8.2",image="docker.io/cilium/cilium",latest_version="v1.8.2",namespace="kube-system",pod="cilium-69twj"} 1

root@node1:/opt# kubectl describe pod version-checker-7f45545d65-5299h -n monitoring
Name:         version-checker-7f45545d65-5299h
Namespace:    monitoring
Priority:     0
Node:         node3/192.168.2.12
Start Time:   Tue, 25 Aug 2020 08:41:01 +0000
Labels:       app=version-checker
              pod-template-hash=7f45545d65
Annotations:  enable.version-checker.io/version-checker: true
              prometheus.io/path: /metrics
              prometheus.io/port: 8080
              prometheus.io/scrape: true
...
root@node1:/opt# k describe svc version-checker -n monitoring
Name:              version-checker
Namespace:         monitoring
Labels:            app=version-checker
Annotations:       kubectl.kubernetes.io/last-applied-configuration:
                     {"apiVersion":"v1","kind":"Service","metadata":{"annotations":{},"labels":{"app":"version-checker"},"name":"version-checker","namespace":"...
Selector:          app=version-checker
Type:              ClusterIP
IP:                10.244.238.181
Port:              web  8080/TCP
TargetPort:        8080/TCP
Endpoints:         172.20.2.171:8080
Session Affinity:  None
Events:            <none>

root@node1:/opt# k get servicemonitor -n monitoring -l app=version-checker -o yaml
apiVersion: v1
items:
- apiVersion: monitoring.coreos.com/v1
  kind: ServiceMonitor
  metadata:
    annotations:
      kubectl.kubernetes.io/last-applied-configuration: |
        {"apiVersion":"monitoring.coreos.com/v1","kind":"ServiceMonitor","metadata":{"annotations":{},"labels":{"app":"version-checker"},"name":"version-checker","namespace":"monitoring"},"spec":{"endpoints":[{"path":"/metrics","port":"web"}],"namespaceSelector":{"matchNames":["monitoring"]},"selector":{"matchLabels":{"app":"version-checker"}}}}
    creationTimestamp: "2020-08-25T08:41:17Z"
    generation: 1
    labels:
      app: version-checker
    name: version-checker
    namespace: monitoring
    resourceVersion: "35804818"
    selfLink: /apis/monitoring.coreos.com/v1/namespaces/monitoring/servicemonitors/version-checker
    uid: 7d2671c4-8af1-4e22-a41f-ff349ff98c04
  spec:
    endpoints:
    - path: /metrics
      port: web
    namespaceSelector:
      matchNames:
      - monitoring
    selector:
      matchLabels:
        app: version-checker
kind: List
metadata:
  resourceVersion: ""
  selfLink: ""

root@node1:/opt# k describe svc version-checker -n monitoring
Name:              version-checker
Namespace:         monitoring
Labels:            app=version-checker
...

apiVersion: monitoring.coreos.com/v1
kind: Prometheus
metadata:
  name: version-checker
  labels:
    prometheus: version-checker
    app.kubernetes.io/name: version-checker
spec:
  replicas: 1
  serviceAccountName: prometheus
  version: v2.20.1
  serviceMonitorSelector:
    matchLabels:
      app: version-checker

  podMonitorSelector:
    matchLabels:
      release: prom
...
  serviceMonitorSelector:
    matchLabels:
      release: prom

  labels:
    app: version-checker
    release: prom