我知道了：

ServiceMonitor：

  apiVersion：monitoring.coreos.com/v1 
类型：ServiceMonitor 
元数据：
名称：prometheus-operator-buygroup 
命名空间：监视
标签：
应用程序：prometheus-operator-buygroup 
版本：prometheus-operator 
规范：
选择器：
 matchLabel：
＃目标应用程序服务
 app.kubernetes.io/实例：buygroup 
应用程序.kubernetes.io /名称：buygroup 
端点：$ b​​ $ b-间隔：15s 
路径：/ metrics 
端口：http 
 na mespaceSelector：
任意：true 
 

服务：

  api版本：v1 
类型：服务
元数据：
名称：prometheus-operator-buygroup 
标签：
应用程序：buygroup 
 app.kubernetes.io/实例：buygroup 
 app.kubernetes.io/名称：buygroup 
规格：
类型：ClusterIP 
端口：
-名称：http 
协议：TCP 
端口：80 
目标端口：http 
选择器：
应用程序：buygroup 
 app.kubernetes.io/实例：buygroup 
 app.kubernetes.io/名称：buygroup 
 

I have successfully setup prometheus and grafana on my kubernetes dev cluster (following this: https://itnext.io/kubernetes-monitoring-with-prometheus-in-15-minutes-8e54d1de2e13).

Added this to Startup.cs for my sample .net core app:

    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        var counter = Metrics.CreateCounter("PathCounter", "Counts requests to endpoints", new CounterConfiguration
        {
            LabelNames = new[] { "method", "endpoint" }
        });
        app.Use((context, next) =>
        {
            counter.WithLabels(context.Request.Method, context.Request.Path).Inc();
            return next();
        });
        app.UseMetricServer();

Should I specify anything for app.UseMetricServer(HERE?);

I've applied this yaml to add my app to be scraped:

apiVersion: monitoring.coreos.com/v1
kind: ServiceMonitor
metadata:
  name: buygroup
  labels:
    app: buygroup
    release: prom
spec:
  namespaceSelector:
    any: true
  selector:
    matchLabels:
      app: buygroup
  endpoints:
  - port: web
    interval: 10s

I don't see anything collected in Targets under: http://localhost:9090/targets

Installed .net dashboard but shows no results:

What do I have to do to have results scraped from my app "buygroup"?

Service yaml:

apiVersion: v1
kind: Service
metadata:
  name: buygroup
  labels:
    name: buygroup
spec:
  type: NodePort
  selector:
    app.kubernetes.io/instance: buygroup
    app.kubernetes.io/name: buygroup
  ports:
  - name: http
    port: 80
    nodePort: 30601
    targetPort: http

Service Monitor:

apiVersion: monitoring.coreos.com/v1
kind: ServiceMonitor
metadata:
  name: monitoring-buygroup
  namespace: monitoring
  labels:
    app: buygroup
spec:
  selector:
    matchLabels:
      # Target app service
      app: buygroup
  endpoints:
  - interval: 15s
    path: /metrics
    port: http
  namespaceSelector:
    matchNames:
    - buygroup-namespace

I figured it out:

ServiceMonitor:

apiVersion: monitoring.coreos.com/v1
kind: ServiceMonitor
metadata:
  name: prometheus-operator-buygroup
  namespace: monitoring
  labels:
    app: prometheus-operator-buygroup
    release: prometheus-operator
spec:
  selector:
    matchLabels:
      # Target app service
      app.kubernetes.io/instance: buygroup
      app.kubernetes.io/name: buygroup
  endpoints:
  - interval: 15s
    path: /metrics
    port: http
  namespaceSelector:
    any: true

Service:

apiVersion: v1
kind: Service
metadata:
  name: prometheus-operator-buygroup
  labels:
    app: buygroup
    app.kubernetes.io/instance: buygroup
    app.kubernetes.io/name: buygroup
spec:
  type: ClusterIP
  ports:
  - name: http
    protocol: TCP
    port: 80
    targetPort: http
  selector:
    app: buygroup
    app.kubernetes.io/instance: buygroup
    app.kubernetes.io/name: buygroup