kubernetes - 向prometheus-operator添加新的服务指标

Question

我正在按Helm图表将Prometheus-operator部署到群集中，但是我实现了自定义服务以监视我的应用程序，我需要将服务添加到Prometheus-operator中才能查看指标数据。
我该怎么做？

Answer 1

首先，您需要通过Helm或手动部署Prometheus-operator:

# By Helm:
$ helm install stable/prometheus-operator --generate-name
 
# By manual: for release `release-0.41`
kubectl apply -f  https://raw.githubusercontent.com/prometheus-operator/prometheus-operator/release-0.41/bundle.yaml

如果您的集群启用了RBAC，则需要为 Prometheus对象安装RBAC:

apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRole
metadata:
  name: prometheus
rules:
- apiGroups: [""]
  resources:
  - nodes
  - nodes/metrics
  - services
  - endpoints
  - pods
  verbs: ["get", "list", "watch"]
- apiGroups: [""]
  resources:
  - configmaps
  verbs: ["get"]
- nonResourceURLs: ["/metrics"]
  verbs: ["get"]
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: prometheus
  namespace: default
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
  name: prometheus
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: prometheus
subjects:
- kind: ServiceAccount
  name: prometheus
  namespace: default

然后，您需要部署 Promethues对象:

apiVersion: monitoring.coreos.com/v1
kind: Prometheus
metadata:
  name: prometheus
  labels:
    prometheus: prometheus
spec:
  replicas: 1
  serviceAccountName: prometheus
  serviceMonitorSelector:
    matchLabels:
      k8s-app: prometheus
  serviceMonitorNamespaceSelector:
    matchLabels:
      prometheus: prometheus
  resources:
    requests:
      memory: 400Mi

在这里， Prometheus对象将选择满足以下条件的所有 ServiceMonitor:

ServiceMonitor将带有k8s-app: prometheus标签。

ServiceMonitor将在带有prometheus: prometheus标签的 namespace 中创建。

ServiceMonitor具有标签选择器，可以选择服务及其底层Endpoint对象。示例应用程序的Service对象通过具有 app值的 example-app标签选择Pod。服务对象还指定公开度量标准的端口。

kind: Service
apiVersion: v1
metadata:
  name: example-app
  labels:
    app: example-app
spec:
  selector:
    app: example-app
  ports:
  - name: web
    port: 8080

该Service对象由ServiceMonitor发现，后者以相同的方式进行选择。 app标签必须具有值 example-app。

apiVersion: monitoring.coreos.com/v1
kind: ServiceMonitor
metadata:
  name: example-app
  labels:
    k8s-app: prometheus
spec:
  selector:
    matchLabels:
      app: example-app
  namespaceSelector:
    # matchNames:
    # - demo
    any: true
  endpoints:
  - port: web

在这里， namespaceSelector用于选择创建服务的所有 namespace 。您可以使用 matchNames指定特定的任何 namespace 。
您还可以根据需要在任何 namespace 中创建 ServiceMonitor。但是您需要在 Prometheus cr的 spec中指定它，例如:

  serviceMonitorNamespaceSelector:
    matchLabels:
      prometheus: prometheus

上面的 serviceMonitorNamespaceSelector在 Prometheus运算符中用于选择带有标签 prometheus: prometheus的 namespace 。假设您有一个命名空间 demo，并且在此 demo命名空间中创建了 Prometheus，然后需要使用patch在 prometheus: prometheus命名空间中添加标签 demo:

$ kubectl patch namespace demo -p '{"metadata":{"labels": {"prometheus":"prometheus"}}}'

您可以在此处找到更多详细信息:

Helm :https://github.com/helm/charts/tree/master/stable/prometheus-operator

手册:https://github.com/prometheus-operator/prometheus-operator/blob/release-0.41/Documentation/user-guides/getting-started.md

namespace 选择器:https://github.com/prometheus-operator/prometheus-operator/blob/master/Documentation/design.md