在prometheus operator中实现服务自动发现和数据持久化

1、在prometheus operator中实现服务自动发现
通过添加额外的配置进行服务发现，自动监控
$ vim prometheus-additional.yaml

- job_name: 'kubernetes-service-endpoints'
  kubernetes_sd_configs:
  - role: endpoints
  relabel_configs:
  - source_labels: [__meta_kubernetes_service_annotation_prometheus_io_scrape]
    action: keep
    regex: true
  - source_labels: [__meta_kubernetes_service_annotation_prometheus_io_scheme]
    action: replace
    target_label: __scheme__
    regex: (https?)
  - source_labels: [__meta_kubernetes_service_annotation_prometheus_io_path]
    action: replace
    target_label: __metrics_path__
    regex: (.+)
  - source_labels: [__address__, __meta_kubernetes_service_annotation_prometheus_io_port]
    action: replace
    target_label: __address__
    regex: ([^:]+)(?::\d+)?;(\d+)
    replacement: $1:$2
  - action: labelmap
    regex: __meta_kubernetes_service_label_(.+)
  - source_labels: [__meta_kubernetes_namespace]
    action: replace
    target_label: kubernetes_namespace
  - source_labels: [__meta_kubernetes_service_name]
    action: replace
    target_label: kubernetes_name

要想自动发现集群中的 Service，就需要我们在 Service 的annotation区域添加prometheus.io/scrape=true的声明

使用上述配置文件创建secret
$ kubectl create secret generic additional-configs --from-file=prometheus-additional.yaml -n monitoring
$ kubectl get secret additional-configs -n monitoring -o yaml
使用secret
$ kubectl get prometheus -n monitoring
$ kubectl edit prometheus k8s -n monitoring
或者修改prometheus-prometheus.yaml文件

apiVersion: monitoring.coreos.com/v1
kind: Prometheus
metadata:
  labels:
    prometheus: k8s
  name: k8s
  namespace: monitoring
spec:
  alerting:
    alertmanagers:
    - name: alertmanager-main
      namespace: monitoring
      port: web
  baseImage: quay.io/prometheus/prometheus
  nodeSelector:
    beta.kubernetes.io/os: linux
  replicas: 2
  secrets:
  - etcd-certs
  resources:
    requests:
      memory: 400Mi
  ruleSelector:
    matchLabels:
      prometheus: k8s
      role: alert-rules
  securityContext:
    fsGroup: 2000
    runAsNonRoot: true
    runAsUser: 1000
  additionalScrapeConfigs:
    name: additional-configs
    key: prometheus-additional.yaml
  serviceAccountName: prometheus-k8s
  serviceMonitorNamespaceSelector: {}
  serviceMonitorSelector: {}
  version: v2.5.0

$ kubectl logs -f prometheus-k8s-0 prometheus -n monitoring

修改权限
Prometheus 绑定了一个名为 prometheus-k8s 的 ServiceAccount 对象，而这个对象绑定的是一个名为 prometheus-k8s 的 ClusterRole
$ cat prometheus-clusterRole.yaml

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: prometheus-k8s
rules:
- apiGroups:
  - ""
  resources:
  - nodes
  - services
  - endpoints
  - pods
  - nodes/proxy
  verbs:
  - get
  - list
  - watch
- apiGroups:
  - ""
  resources:
  - configmaps
  - nodes/metrics
  verbs:
  - get
- nonResourceURLs:
  - /metrics
  verbs:
  - get

2、为prometheus operator实现数据持久化
创建一个StorageClass对象

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: prometheus-data-db
provisioner: fuseim.pri/ifs

在pvc模板中使用存储类prometheus-data-db
$ cat prometheus-prometheus.yaml

apiVersion: monitoring.coreos.com/v1
kind: Prometheus
metadata:
  labels:
    prometheus: k8s
  name: k8s
  namespace: monitoring
spec:
  alerting:
    alertmanagers:
    - name: alertmanager-main
      namespace: monitoring
      port: web
  storage:
    volumeClaimTemplate:
      spec:
        storageClassName: prometheus-data-db
        resources:
          requests:
            storage: 10Gi
  baseImage: quay.io/prometheus/prometheus
  nodeSelector:
    beta.kubernetes.io/os: linux
  replicas: 2
  secrets:
  - etcd-certs
  additionalScrapeConfigs:
    name: additional-configs
    key: prometheus-additional.yaml
  resources:
    requests:
      memory: 400Mi
  ruleSelector:
    matchLabels:
      prometheus: k8s
      role: alert-rules
  securityContext:
    fsGroup: 2000
    runAsNonRoot: true
    runAsUser: 1000
  serviceAccountName: prometheus-k8s
  serviceMonitorNamespaceSelector: {}
  serviceMonitorSelector: {}
  version: v2.5.0

更新完成后会自动生成两个 PVC 和 PV 资源对象，因为副本数是2
$ kubectl get pvc -n monitoring
$ kubectl get pv
$ kubectl get pod prometheus-k8s-0 -n monitoring -o yaml