https证书突然过期，导致某个业务出现问题，这个问题还是存在，本文通过blackbox exporter来监控ssl证书到期时间，由于之前已经部署blackbox，这里就不复述k8s部署blackbox

Prometheus配置blackbox采集

由于已经基于k8s部署prometheus，且将其配置参数写到ConfigMap资源中，然后通过挂载ConfigMap到Pod内部，这样修改ConfigMap就可以修改Prometheus配置

[root@k8s01 prometheus]# vim prometheus-config.yaml 
apiVersion: v1
kind: ConfigMap
metadata:
  name: prometheus-config
  namespace: monitoring
data:
  prometheus.yml: |
    global:
      scrape_interval:     15s
      evaluation_interval: 15s
      external_labels:
        cluster: "kubernetes"

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

    rule_files:
    - /etc/prometheus/*-rule.yml
        
    scrape_configs:
...
    - job_name: 'ssl'
      metrics_path: /probe
      params:
        module:
        - "http_get_2xx"
        - "http_get_3xx"
      static_configs:
        - targets:
          - http://prometheus.io
          - https://prometheus.io
          - https://jd.com
          - https://www.bejson.com
      relabel_configs:
        - source_labels: [__address__]
          target_label: __param_target
        - source_labels: [__param_target]
          target_label: instance
        - target_label: __address__
          replacement: blackbox-exporter.monitoring:9115
...
[root@k8s01 prometheus]# kubectl apply -f prometheus-config.yaml 
configmap/prometheus-config configured

重载prometheus配置

[root@k8s01 prometheus]# curl -XPOST http://10.x.x.x:30089/-/reload

Prometheus UI界面查看

Targets显示如下信息，blackbox采集数据成功

Grafana引入监控模板

登入Grafana界面，点击Grafana左侧栏菜单，选择Manage菜单，进入后点击右上角 Import按钮，设置Import的ID号为13230，引入模板，然后点击Load按钮进入配置数据库，选择使用Prometheus数据库，之后点击Import按钮进入看板

Prometheus配置告警

修改Prometheus的ConfigMap，添加对应的告警规则

[root@k8s01 prometheus]# vim prometheus-config.yaml 
apiVersion: v1
kind: ConfigMap
metadata:
  name: prometheus-config
  namespace: monitoring
data:
  prometheus.yml: |
    global:
      scrape_interval:     15s
      evaluation_interval: 15s
      external_labels:
        cluster: "kubernetes"

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

    rule_files:
    - /etc/prometheus/*-rule.yml
...
    test-rule.yml: |
    groups:
    - name: 证书还有30天过期
      rules:
      - alert: SslCertificateWillExpireSoon
        expr: probe_ssl_earliest_cert_expiry - time() < 86400 * 30
        for: 1m
        labels:
          severity: warning
        annotations:
          summary: "SSL certificate will expire soon (instance {{ $labels.instance }})"
          description: "SSL certificate expires in 30 days\n  VALUE = {{ $value }}\n  LABELS: {{ $labels }}"

    - name: 证书已过期
      rules:
      - alert: SslCertificateExpired
        expr: probe_ssl_earliest_cert_expiry - time()  <= 0
        for: 1m
        labels:
          severity: error
        annotations:
          summary: "SSL certificate expired (instance {{ $labels.instance }})"
          description: "SSL certificate has expired already\n  VALUE = {{ $value }}\n  LABELS: {{ $labels }}"

[root@k8s01 prometheus]# kubectl apply -f prometheus-config.yaml 
configmap/prometheus-config configured          

重载prometheus配置

[root@k8s01 prometheus]# curl -XPOST http://10.105.x.x:30089/-/reload

查看告警是否生效