为什么我的Prometheus操作符ServiceMonitor需要一个“`release`”标签才能正常运行？

Question

当我部署这个时：

kind: ServiceMonitor
apiVersion: monitoring.coreos.com/v1
metadata:
  labels:
    app: complaints-monitor
    release: prometheus # <---------
  name: complaints-monitor-svc-monitor
  namespace: default
spec:
  endpoints:
    - path: /metrics
      port: web
  namespaceSelector:
    matchNames:
      - default
  selector:
    matchLabels:
      app: complaints-monitor

我的服务在普罗米修斯的目标下出现并正常运行。

如果应用以下内容，则目标将消失：

kind: ServiceMonitor
apiVersion: monitoring.coreos.com/v1
metadata:
  labels:
    app: complaints-monitor
  name: complaints-monitor-svc-monitor
  namespace: default
spec:
  endpoints:
    - path: /metrics
      port: web
  namespaceSelector:
    matchNames:
      - default
  selector:
    matchLabels:
      app: complaints-monitor

Answer 1

在检查了values.yaml of kube-prometheus-stack之后才发现了这个问题

• vaules.yaml

    ## If true, a nil or {} value for prometheus.prometheusSpec.serviceMonitorSelector will cause the
    ## prometheus resource to be created with selectors based on values in the helm deployment,
    ## which will also match the servicemonitors created
    ##
    serviceMonitorSelectorNilUsesHelmValues: true


    ## ServiceMonitors to be selected for target discovery.
    ## If {}, select all ServiceMonitors
    ##
    serviceMonitorSelector: {}
    ## Example which selects ServiceMonitors with label "prometheus" set to "somelabel"
    # serviceMonitorSelector:
    #   matchLabels:
    #     prometheus: somelabel

当您使用helm安装kube-prometheus-stack时，它会向Kubernetes资源添加label release: <prometheus-installed-namespace>。

如果设置serviceMonitorSelectorNilUsesHelmValues是true，则将向prometheus.prometheusSpec.serviceMonitorSelector添加选择器，在您的情况下是release: prometheus。

您将能够看到prometheus用命令选择serviceMonitor的选择器

kubectl -n <prometheus-installed-namespace> get prometheus -o yaml

并搜索serviceMonitorSelector。

在不添加release标签的情况下，您有两个选项可以使它工作

1. 将serviceMonitorSelectorNilUsesHelmValues设置为false，然后prometheus将选择所有serviceMonitor
2. 或者，将serviceMonitorSelector设置为任何您喜欢的标签。