prometheus 监控 k8s pod 容器服务状态

Prometheus+Grafana作为监控K8S的解决方案，大部分都是在K8S集群内部部署，所以监控起来很方便，可以直接调用集群内的cert及各种监控url，但是增加了集群的资源开销，

**需求：**每个 pod 重启/删除时，都能发出告警。要及时和准确

前几期也讲过 报警，可以回顾哦

实现 效果

配置 rbac 相关认证
Prometheus 需要访问 Kubernetes 的一些资源对象，所以需要配置 rbac 相关认证，内容如下：

1）创建一个用于Prometheus pod 中的ServiceAccount
2）创建ClusterRole，定义规则权限
3）创建ClusterRoleBinding 将ServiceAccount 与 ClusterRole进行绑定

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

1.配置 prometheus-config
告警规则 和 监控

    - job_name: 'kubernetes-services'
      kubernetes_sd_configs:
      - role: service
      metrics_path: /probe
      params:
        module: [http_2xx]
      relabel_configs:
      - source_labels: [__meta_kubernetes_service_annotation_prometheus_io_probe]
        action: keep
        regex: true
      - source_labels: [__address__]
        target_label: __param_target
      - target_label: __address__
        replacement: blackbox-exporter.example.com:9115
      - source_labels: [__param_target]
        target_label: instance
      - action: labelmap
        regex: __meta_kubernetes_service_label_(.+)
      - source_labels: [__meta_kubernetes_namespace]
        target_label: kubernetes_namespace
      - source_labels: [__meta_kubernetes_service_name]
        target_label: kubernetes_name



    - job_name: 'kubernetes-pods'
      kubernetes_sd_configs:
      - role: pod
      relabel_configs:
      - source_labels: [__meta_kubernetes_pod_annotation_prometheus_io_scrape]
        action: keep
        regex: true
      - source_labels: [__meta_kubernetes_pod_annotation_prometheus_io_path]
        action: replace
        target_label: __metrics_path__
        regex: (.+)
      - source_labels: [__address__, __meta_kubernetes_pod_annotation_prometheus_io_port]
        action: replace
        regex: ([^:]+)(?::\d+)?;(\d+)
        replacement: $1:$2
        target_label: __address__
      - action: labelmap
        regex: __meta_kubernetes_pod_label_(.+)
      - source_labels: [__meta_kubernetes_namespace]
        action: replace
        target_label: kubernetes_namespace
      - source_labels: [__meta_kubernetes_pod_name]
        action: replace
        target_label: kubernetes_pod_name


    - job_name: 'kubernetes-nodes'
      kubernetes_sd_configs:
      - role: node
      scheme: https
      tls_config:
        ca_file: /var/run/secrets/kubernetes.io/serviceaccount/ca.crt
      bearer_token_file: /var/run/secrets/kubernetes.io/serviceaccount/token
      relabel_configs:
      - action: labelmap
        regex: __meta_kubernetes_node_label_(.+)
      - target_label: __address__
        replacement: kubernetes.default.svc:443
      - source_labels: [__meta_kubernetes_node_name]
        regex: (.+)
        target_label: __metrics_path__
        replacement: /api/v1/nodes/${1}/proxy/metrics


---

告警规则

    - name: Down
      rules:
      - alert: Down
        expr: up == 0
        for: 30s
        labels:
          severity: critical
        annotations:
          description: "服务不可用，已经掉线"


      - alert: NodeCPUHigh
        expr: (1 - avg by (instance) (irate(node_cpu_seconds_total{mode="idle"}[5m]))) * 100 > 75
        for: 5m
        labels:
          severity: warning
        annotations:
          description: "{{$labels.instance}}: CPU usage is above 75% (当前值：{{ $value }})"
 
      - alert: NodeCPUIowaitHigh
        expr: avg by (instance) (irate(node_cpu_seconds_total{mode="iowait"}[5m])) * 100 > 50
        for: 5m
        labels:
          severity: warning
        annotations:
          description: "{{$labels.instance}}: CPU iowait usage is above 50% (当前值：{{ $value }})"

 
      - alert: NodeMemoryUsageHigh
        expr: (1 - node_memory_MemAvailable_bytes / node_memory_MemTotal_bytes) * 100 > 90
        for: 5m
        labels:
          severity: warning
        annotations:
          description: "{{$labels.instance}}: Memory usage is above 90% (当前值：{{ $value }})"
 
      - alert: NodeDiskRootLow
        expr: (1 - node_filesystem_avail_bytes{fstype=~"ext.*|xfs",mountpoint ="/"} / node_filesystem_size_bytes{fstype=~"ext.*|xfs",mountpoint ="/"}) * 100 > 80
        for: 10m
        labels:
          severity: warning
        annotations:
          description: "{{$labels.instance}}: Disk(the / partition) usage is above 80% (当前值：{{ $value }})"
        
      - alert: NodeDiskBootLow
        expr: (1 - node_filesystem_avail_bytes{fstype=~"ext.*|xfs",mountpoint ="/boot"} / node_filesystem_size_bytes{fstype=~"ext.*|xfs",mountpoint ="/boot"}) * 100 > 80
        for: 10m
        labels:
          severity: warning
        annotations:
          description: "{{$labels.instance}}: Disk(the /boot partition) usage is above 80% (当前值：{{ $value }})"
 
      - alert: NodeLoad5High
        expr: (node_load5) > (count by (instance) (node_cpu_seconds_total{mode='system'}) * 2)
        for: 5m
        labels:
          severity: warning
        annotations:
          description: "{{$labels.instance}}: Load(5m) is 2 times the number of CPU cores (当前值：{{ $value }})"

Deployment部署应用
1）将前面创建的pvc和配置文件configMap 作为volume挂载到Prometheus 中
2）在Prometheus中使用前面创建的ServiceAccount

apiVersion: apps/v1
kind: Deployment
metadata:
  name: prometheus
  namespace: monitor
  labels:
    app: prometheus
spec:
  selector:
    matchLabels:
      app: prometheus
  template:
    metadata:
      labels:
        app: prometheus
    spec:
      securityContext:                                   #指定运行的用户为root
        runAsUser: 0
      serviceAccountName: prometheus
      containers:
      - image: prom/prometheus:v2.30.2
        name: prometheus
        args:
        - "--config.file=/etc/prometheus/prometheus.yml" #通过volume挂载prometheus.yml
        - "--storage.tsdb.path=/prometheus"              #通过vlolume挂载目录/prometheus
        - "--storage.tsdb.retention.time=24h"
        - "--web.enable-admin-api"                       #控制对admin HTTP API的访问，其中包括删除时间序列等功能
        - "--web.enable-lifecycle"                       #支持热更新，直接执行localhost:9090/-/reload立即生效
        ports:
        - containerPort: 9090
          name: http
        resources:
          requests:
            cpu: '1'
            memory: 1000Mi
          limits:
            cpu: '2.5'
            memory: 2000Mi       
               
        volumeMounts:
        - mountPath: "/etc/prometheus"
          name: config-volume
        - mountPath: "/prometheus"
          name: data
        - name: rules
          mountPath: /etc/prometheus-rules
      volumes:
      - name: data
        emptyDir: {}
      - name: config-volume
        configMap:
          name: prometheus-config    
      - name: rules
        configMap:
          name: prometheus-rules
          
---
apiVersion: v1
kind: Service
metadata:
  name: prometheus
  namespace: monitor
  labels:
    app: prometheus
spec:
  selector:
    app: prometheus
  type: NodePort
  ports:
  - port: 9090
    targetPort: 9090
    nodePort: 30003

然后需要在你的k8s容器服务里添加

```bash
  template:
    metadata:
      annotations:
        prometheus.io/scrape: "true"
        prometheus.io/port: "$JAR_PORD"

运行一个 demo

$a=web-admin
kubectl  apply -f demo.yaml

修复问题后