k8s容器中通过Prometheus Operator部署Elasticsearch Exporter监控Elasticsearch

写在前面

在按照下面步骤操作之前，请先确保服务器已经部署k8s，prometheus，prometheus operator以及ElasticSearch，关于这些环境的部署，可以自行查找相关资料安装部署，本文档便不在此赘述。

关于prometheus监控这部分，大致的系统架构图如下，感兴趣的同学可以自行研究一下，这里就不再具体说明。

1、Deployment（工作负载）以及Service（服务）部署

配置yaml可参考如下：

---
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: elasticsearch-exporter
  name: elasticsearch-exporter
  namespace: prometheus-exporter
spec:
  replicas: 1
  selector:
    matchLabels:
      app: elasticsearch-exporter
  template:
    metadata:
      annotations:
        prometheus.io/scrape: 'true'  
        prometheus.io/port: '9114'
        prometheus.io/path: 'metrics'
      labels:
        app: elasticsearch-exporter
    spec:
      containers:
      - command:
        - '/bin/elasticsearch_exporter'
        # 设置账号密码格式参考：--es.uri=http://username:password@localhost:9200
        - '--es.uri=http://admin:123456@es-cluster.monitorsoftware:9200'
        image: prometheuscommunity/elasticsearch-exporter:v1.5.0
        imagePullPolicy: IfNotPresent
        name: elasticsearch-exporter
        ports:
        - containerPort: 9114

---
apiVersion: v1
kind: Service
metadata:
  labels:
    app: elasticsearch-exporter
  name: elasticsearch-exporter-svc
  namespace: prometheus-exporter
spec:
  ports:
  - name: http
    port: 9114
    protocol: TCP
    targetPort: 9114
  selector:
    app: elasticsearch-exporter
  type: ClusterIP

说明：

1> 关于yaml中配置，prometheus operator官方也有对应的模板说明，官方地址如下：https://github.com/prometheus-community/elasticsearch_exporter

2> 关于elasticsearch exporter 镜像版本可以根据需要选择对应的版本，官方镜像仓库地址如下：https://hub.docker.com/r/prometheuscommunity/elasticsearch-exporter/tags

3> 部署成功图如下：

（1）Deployment（工作负载）

（2）Service（服务）

2、创建ServiceMonitor配置文件

yaml配置文件如下：

---
apiVersion: monitoring.coreos.com/v1
kind: ServiceMonitor
metadata:
  labels:
    app: elasticsearch-exporter
  name: elasticsearch-exporter-
  namespace: prometheus-exporter
spec:
  endpoints:
    - honorLabels: true
      interval: 1m
      path: /metrics
      port: http
      scheme: http
      params:
        target:
          - 'es-cluster.monitorsoftware:9200'
      relabelings:
        - sourceLabels: [__param_target]
          targetLabel: instance
  namespaceSelector:
    matchNames:
      - prometheus-exporter
  selector:
    matchLabels:
      app: elasticsearch-exporter

说明：

1> prometheus operator是通过ServiceMonitor发现监控目标，并对其进行监控。serviceMonitor 是对service 获取数据的一种方式。

• promethus-operator可以通过serviceMonitor 自动识别带有某些 label 的service ，并从这些service 获取数据。
• serviceMonitor 也是由promethus-operator 自动发现的。

2> prometheus监控过程如下：

 3> 部署成功图如下

（1）serviceMonitor部署

（2）Prometheus部署成功图

3、Prometheus告警规则配置 

 prometheus rule规则配置：

---
apiVersion: monitoring.coreos.com/v1
kind: PrometheusRule
metadata:
  labels:
    prometheus: k8s
    role: alert-rules
  name: elasticsearch-exporter-rules
  namespace: k8s-monitor-system
spec:
  groups:
    - name: elasticsearch-exporter
      rules:
        - alert: es-ElasticsearchHealthyNodes
          expr: elasticsearch_cluster_health_number_of_nodes < 3
          for: 0m
          labels:
            severity: critical
          annotations:
            summary: Elasticsearch Healthy Nodes (instance {{ $labels.instance }})
            description: "Missing node in Elasticsearch cluster\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"
        - alert: es-ElasticsearchClusterRed
          expr: elasticsearch_cluster_health_status{color="red"} == 1
          for: 0m
          labels:
            severity: critical
          annotations:
            summary: Elasticsearch Cluster Red (instance {{ $labels.instance }})
            description: "Elastic Cluster Red status\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"
        - alert: es-ElasticsearchClusterYellow
          expr: elasticsearch_cluster_health_status{color="yellow"} == 1
          for: 0m
          labels:
            severity: warning
          annotations:
            summary: Elasticsearch Cluster Yellow (instance {{ $labels.instance }})
            description: "Elastic Cluster Yellow status\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"
        - alert: es-ElasticsearchDiskOutOfSpace
          expr: elasticsearch_filesystem_data_available_bytes / elasticsearch_filesystem_data_size_bytes * 100 < 10
          for: 0m
          labels:
            severity: critical
          annotations:
            summary: Elasticsearch disk out of space (instance {{ $labels.instance }})
            description: "The disk usage is over 90%\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"
        - alert: es-ElasticsearchHeapUsageTooHigh
          expr: (elasticsearch_jvm_memory_used_bytes{area="heap"} / elasticsearch_jvm_memory_max_bytes{area="heap"}) * 100 > 90
          for: 2m
          labels:
            severity: critical
          annotations:
            summary: Elasticsearch Heap Usage Too High (instance {{ $labels.instance }})
            description: "The heap usage is over 90%\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"
        - alert: es-ElasticsearchHealthyDataNodes
          expr: elasticsearch_cluster_health_number_of_data_nodes < 3
          for: 0m
          labels:
            severity: critical
          annotations:
            summary: Elasticsearch Healthy Data Nodes (instance {{ $labels.instance }})
            description: "Missing data node in Elasticsearch cluster\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"

说明：

1> prometheusRule规则配置，可以参考模板配置，模板网址如下：https://awesome-prometheus-alerts.grep.to/rules#elasticsearch

2> 部署成功图如下：

 4、Grafana部署图

4.1、grafana dashboard地址如下：https://grafana.com/grafana/dashboards

        官方推荐模板ID为：14191

4.2、dashboard效果图如下