# AlertManager进行告警

## 安装AlertManager

github上给了AlertManager的几种安装方法：（[https://github.com/prometheus/alertmanager）。](https://github.com/prometheus/alertmanager%EF%BC%89%E3%80%82)

这里，我们使用二进制进行安装。首先下载二进制文件，这里我们下载最新版本`0.20.0`（[https://prometheus.io/download/#alertmanager）](https://prometheus.io/download/#alertmanager%EF%BC%89)

```
$ wget https://github.com/prometheus/alertmanager/releases/download/v0.20.0/alertmanager-0.20.0.linux-amd64.tar.gz
```

同样，我们使用`systemd`来管理这个服务。我们把解压后的整个`alertmanager-0.20.0.linux-amd64`文件夹移动到`/usr/local/`目录下，并重命名为`alertmanager`

```
$ mv ./alertmanager-0.20.0.linux-amd64 /usr/local/alertmanager
```

然后创建文件`/usr/lib/systemd/system/alertmanager.service`，内容如下

```
[Unit]
Description=alertmanager
After=network.target

[Service]
Type=simple
ExecStart=/usr/local/alertmanager/alertmanager --config.file /usr/local/alertmanager/alertmanager.yml --storage.path=/var/lib/alertmanager
Restart=on-failure

[Install]
WantedBy=multi-user.target
```

编辑`/usr/local/alertmanager/alertmanager.yml`，内容如下（参考【1】【2】：

```
global:
  smtp_smarthost: 'smtp.163.com:25'    # 使用163邮箱服务器发邮件
  smtp_from: 'pshizh@163.com'    # 发件人，填写你的163邮箱
  smtp_auth_username: 'pshizh@163.com'  # 你的163邮箱，与上面保持一致
  smtp_auth_password: 'xxxx'  # 你的163邮箱的密码

route:
  group_by: ['example']
  group_wait: 10s
  group_interval: 10s
  repeat_interval: 1h
  receiver: 'email'

receivers:
- name: 'email'
  email_configs:
  - to: '527103524@qq.com'    # 收件人
```

启动alertmanager

```
$ systemctl daemon-reload && systemctl enable alertmanager
$ systemctl start alertmanager && systemctl status alertmanager
```

## 为Prometheus配置AlertManager与告警规则

编辑`/usr/local/prometheus/prometheus.yml`文件，在`alerting`区域与`rule_files`区域添加如下的内容，最终prometheus.yml文件内容如下：

```
# my global config
global:
  scrape_interval:     15s # Set the scrape interval to every 15 seconds. Default is every 1 minute.
  evaluation_interval: 15s # Evaluate rules every 15 seconds. The default is every 1 minute.

# Alertmanager configuration
alerting:
  alertmanagers:
  - static_configs:
    - targets: [ 'localhost:9093' ]

rule_files:
  - "/usr/local/prometheus/rule_files/memory_alert.yml"

scrape_configs:
  - job_name: 'prometheus'
    static_configs:
    - targets: ['localhost:9090']
  - job_name: 'node_exporter'
    static_configs:
    - targets: ['localhost:9100']
```

然后创建文件`/usr/local/prometheus/rule_files/memory_alert.yml`，内容如下：

```
groups:
- name: example        # 尚不清楚是否需要与alertmanager.yml中的route.groupby的名字保持一致
  rules:
  - alert: NodeMemoryUsage
    expr: (node_memory_MemTotal_bytes - node_memory_MemAvailable_bytes) / node_memory_MemTotal_bytes * 100 > 20
    for: 1m
    annotations:
      summary: "{{$labels.instance}}: High Memory usage detected"
      description: "{{$labels.instance}}: Memory usage is above 20% (current value is:{{ $value }})"
```

不久后，便可以接收到告警邮件，如下

![](https://735702182-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-M69DxRoC8HFhJcA2bUu%2Fsync%2Fb6364495a9443d26321174218c3d7d97570c98ed.png?generation=1592397053272580\&alt=media)

## Reference

【1】<https://www.cnblogs.com/longcnblogs/p/9620733.html>\
【2】<https://github.com/prometheus/alertmanager/blob/master/doc/examples/simple.yml>