1.下载Mysqld_exporter相关包：

官网地址： https://github.com/prometheus/mysqld_exporter

→ wget https://github.com/prometheus/mysqld_exporter/releases/download/v0.13.0/mysqld_exporter-0.13.0.linux-amd64.tar.gz

2.解压

→ tar -zxvf mysqld_exporter-0.13.0.linux-amd64.tar.gz
→ mv mysqld_exporter-0.13.0.linux-amd64 mysqld_exporter

3.创建my.cnf文件

→ cd mysqld_exporter
→ vim my.cnf

注意:这个文件中需要写入能够访问数据库的用户名和密码

[client]
user=root
password=

4.创建服务系统文件

→  vim /usr/lib/systemd/system/mysqld_exporter.service

[Unit]
Description=mysqld_exporter
After=network.target

[Service]
User=root
Type=simple
ExecStart=/usr/local/mysql_export/mysqld_exporter/mysqld_exporter  --config.my-cnf  /usr/local/mysql_export/mysqld_exporter/my.cnf  --collect.heartbeat
Restart=on-failure

[Install]
WantedBy=multi-user.target

5.启动服务，设置开机自启

→  systemctl daemon-reload
→  systemctl start mysqld_exporter.service
→  systemctl enable mysqld_exporter.service  #设置开机自启
→  systemctl status mysqld_exporter.service  #查看状态
→  systemctl restart mysqld_exporter.service

6.测试metrics是否生效

查看是否存在mysql_up指标

curl http://localhost:9104/metrics

7.在Prometheus的配置文件prometheus.yml中配置mysql的metries路径

注意：mysqld_exporter默认端口是9104

- job_name: 'mysql'
    static_configs:
    - targets: ['172.**.**.**:9104']

8.热加载Promethues的配置

systemctl reload prometheus.service

9.创建Prometheus报警规则

vim mysql_instance_down.yml

groups:
  - name: mysql_instance_down
    rules:
      - alert: Mysql instance Down
        expr: mysql_up{job="mysql"} == 0
        for: 20s
        labels:
          user: mysql
          severity: error
        annotations:
          summary: "mysql Instance {{ $labels.instance }} down"
          description: "mysql {{ $labels.instance }} has been down for more than 20s."

10.通过Prometheus的AlertManager模块报警

详情请参考：prometheus配置alertmanager告警-钉钉告警