Kubernetes中使用prometheus+alertmanager实现监控告警

摘要：监控告警原型图原型图解释与作为运行在同一个中并交由控制器管理，默认开启端口，因为我们的与是处于同一个中，所以直接使用就可以与通信用于发送告警通知，告警规则配置以的形式挂载到容器供使用，告警通知对象配置也通过挂载到容器供使用，这里我们使用邮件

prometheus与alertmanager作为container运行在同一个pods中并交由Deployment控制器管理，alertmanager默认开启9093端口，因为我们的prometheus与alertmanager是处于同一个pod中，所以prometheus直接使用localhost:9093就可以与alertmanager通信(用于发送告警通知)，告警规则配置rules.yml以Configmap的形式挂载到prometheus容器供prometheus使用，告警通知对象配置也通过Configmap挂载到alertmanager容器供alertmanager使用，这里我们使用邮件接收告警通知，具体配置在alertmanager.yml中

环境：Linux 3.10.0-693.el7.x86_64 x86_64 GNU/Linux
平台：Kubernetes v1.10.5
Tips：prometheus与alertmanager完整的配置在文档末尾

在prometheus中指定告警规则的路径， rules.yml就是用来指定报警规则，这里我们将rules.yml用ConfigMap的形式挂载到/etc/prometheus目录下面即可:

rule_files:
- /etc/prometheus/rules.yml

这里我们指定了一个InstanceDown告警，当主机挂掉1分钟则prometheus会发出告警

  rules.yml: |
    groups:
    - name: example
      rules:
      - alert: InstanceDown
        expr: up == 0
        for: 1m
        labels:
          severity: page
        annotations:
          summary: "Instance {{ $labels.instance }} down"
          description: "{{ $labels.instance }} of job {{ $labels.job }} has been down for more than 1 minutes."

alertmanager默认开启9093端口，又因为我们的prometheus与alertmanager是处于同一个pod中，所以prometheus直接使用localhost:9093就可以与alertmanager通信

alerting:
  alertmanagers:
  - static_configs:
    - targets: ["localhost:9093"]

我们这里举了一个邮件告警的例子，alertmanager接收到prometheus发出的告警时，alertmanager会向指定的邮箱发送一封告警邮件，这个配置也是通过Configmap的形式挂载到alertmanager所在的容器中供alertmanager使用

alertmanager.yml: |-
    global:
      smtp_smarthost: "smtp.exmail.qq.com:465"
      smtp_from: "xin.liu@woqutech.com"
      smtp_auth_username: "xin.liu@woqutech.com"
      smtp_auth_password: "xxxxxxxxxxxx"
      smtp_require_tls: false
    route:
      group_by: [alertname]
      group_wait: 30s
      group_interval: 5m
      repeat_interval: 10m
      receiver: default-receiver
    receivers:
    - name: "default-receiver"
      email_configs:
      - to: "1148576125@qq.com"

在prometheus web ui中可以看到配置的告警规则

为了看测试效果，关掉一个主机节点：
在prometheus web ui中可以看到一个InstanceDown告警被触发

在alertmanager web ui中可以看到alertmanager收到prometheus发出的告警

指定接收告警的邮箱收到alertmanager发出的告警邮件

node_exporter_daemonset.yaml

apiVersion: extensions/v1beta1
kind: DaemonSet
metadata:
  name: node-exporter
  namespace: kube-system
  labels:
    app: node_exporter
spec:
  selector:
    matchLabels:
      name: node_exporter
  template:
    metadata:
      labels:
        name: node_exporter
    spec:
      tolerations:
      - key: node-role.kubernetes.io/master
        effect: NoSchedule
      containers:
      - name: node-exporter
        image: alery/node-exporter:1.0
        ports:
        - name: node-exporter
          containerPort: 9100
          hostPort: 9100
        volumeMounts:
        - name: localtime
          mountPath: /etc/localtime
        - name: host
          mountPath: /host
          readOnly: true
      volumes:
      - name: localtime
        hostPath:
          path: /usr/share/zoneinfo/Asia/Shanghai
      - name: host
        hostPath:
          path: /

alertmanager-cm.yaml

kind: ConfigMap
apiVersion: v1
metadata:
  name: alertmanager
  namespace: kube-system
data:
  alertmanager.yml: |-
    global:
      smtp_smarthost: "smtp.exmail.qq.com:465"
      smtp_from: "xin.liu@woqutech.com"
      smtp_auth_username: "xin.liu@woqutech.com"
      smtp_auth_password: "xxxxxxxxxxxx"
      smtp_require_tls: false
    route:
      group_by: [alertname]
      group_wait: 30s
      group_interval: 5m
      repeat_interval: 10m
      receiver: default-receiver
    receivers:
    - name: "default-receiver"
      email_configs:
      - to: "1148576125@qq.com"

prometheus-rbac.yaml

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

prometheus-cm.yaml

kind: ConfigMap
apiVersion: v1
data:
  prometheus.yml: |
    rule_files:
    - /etc/prometheus/rules.yml
    alerting:
      alertmanagers:
      - static_configs:
        - targets: ["localhost:9093"]
    scrape_configs:
    - job_name: "node"
      kubernetes_sd_configs:
      - role: pod
      relabel_configs:
      - source_labels: [__meta_kubernetes_pod_ip]
        action: replace
        target_label: __address__
        replacement: $1:9100
      - source_labels: [__meta_kubernetes_pod_host_ip]
        action: replace
        target_label: instance
      - source_labels: [__meta_kubernetes_pod_node_name]
        action: replace
        target_label: node_name
      - action: labelmap
        regex: __meta_kubernetes_pod_label_(name)
      - source_labels: [__meta_kubernetes_pod_label_name]
        regex: node_exporter
        action: keep

  rules.yml: |
    groups:
    - name: example
      rules:
      - alert: InstanceDown
        expr: up == 0
        for: 5m
        labels:
          severity: page
        annotations:
          summary: "Instance {{ $labels.instance }} down"
          description: "{{ $labels.instance }} of job {{ $labels.job }} has been down for more than 5 minutes."
      - alert: APIHighRequestLatency
        expr: api_http_request_latencies_second{quantile="0.5"} > 1
        for: 10m
        annotations:
          summary: "High request latency on {{ $labels.instance }}"
          description: "{{ $labels.instance }} has a median request latency above 1s (current value: {{ $value }}s)"

metadata:
  name: prometheus-config-v0.1.0
  namespace: kube-system

prometheus.yaml

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  namespace: kube-system
  name: prometheus
  labels:
    name: prometheus
spec:
  replicas: 1
  selector:
    matchLabels:
      app: prometheus
  template:
    metadata:
      name: prometheus
      labels:
        app: prometheus
    spec:
      serviceAccountName: prometheus
      nodeSelector:
        node-role.kubernetes.io/master: ""
      tolerations:
      - effect: NoSchedule
        key: node-role.kubernetes.io/master
        operator: Exists
      securityContext:
        runAsUser: 0
        fsGroup: 0
      containers:
      - name: prometheus
        image: prom/prometheus:v2.4.0
        args:
        - "--config.file=/etc/prometheus/prometheus.yml"
        ports:
        - name: web
          containerPort: 9090
        volumeMounts:
        - name: prometheus-config
          mountPath: /etc/prometheus
        - name: prometheus-storage
          mountPath: /prometheus
        - name: localtime
          mountPath: /etc/localtime
      - name: alertmanager
        image: prom/alertmanager:v0.14.0
        args:
        - "--config.file=/etc/alertmanager/alertmanager.yml"
        - "--log.level=debug"
        ports:
        - containerPort: 9093
          protocol: TCP
          name: alertmanager
        volumeMounts:
        - name: alertmanager-config
          mountPath: /etc/alertmanager
        - name: alertmanager-storage
          mountPath: /alertmanager
        - name: localtime
          mountPath: /etc/localtime
      volumes:
      - name: prometheus-config
        configMap:
          name: prometheus-config-v0.1.0
      - name: alertmanager-config
        configMap:
          name: alertmanager
      - name: localtime
        hostPath:
          path: /usr/share/zoneinfo/Asia/Shanghai
      - name: prometheus-storage
        hostPath:
          path: /gaea/prometheus
          type: DirectoryOrCreate
      - name: alertmanager-storage
        hostPath:
          path: /gaea/alertmanager
          type: DirectoryOrCreate
---
apiVersion: v1
kind: Service
metadata:
  labels:
    name: prometheus
    kubernetes.io/cluster-service: "true"
  name: prometheus
  namespace: kube-system
spec:
  ports:
  - name: prometheus
    nodePort: 30065
    port: 9090
    protocol: TCP
    targetPort: 9090
  selector:
    app: prometheus
  sessionAffinity: None
  type: NodePort
---
apiVersion: v1
kind: Service
metadata:
  labels:
    name: prometheus
    kubernetes.io/cluster-service: "true"
  name: alertmanager
  namespace: kube-system
spec:
  ports:
  - name: alertmanager
    nodePort: 30066
    port: 9093
    protocol: TCP
    targetPort: 9093
  selector:
    app: prometheus
  sessionAffinity: None
  type: NodePort