alertmanager笔记
1 prometheus的思想
所有告警都应该立刻处理掉，不应该存在长时间未解决的告警。所以具体的表现就是高频的数据采集，和告警的自动恢复（默认5分钟）
2 alertmanager API调用
使用如下命令即可手工制造告警，注意startsAt和endsAt时间为当前实际时间的UTC格式。
curl -H "Content-Type: application/json" -X POST -d '[{"labels":{"字段1": "值1", "字段2": "值2", "字段3": "值3"},"annotations":{"desc": "xxxx"},"generatorURL":"http://1.1.1.1","startsAt":"2022-08-10T20:57:46.000+08:00"}]' "http://127.0.0.1:9093/api/v2/alerts"
3 alertmanager告警json
alertmanager发送给receiver的为一个json，多条告警形成alerts数组，示例如下：
'{"receiver": "email", "status": "firing", "alerts": [{"status": "firing", "labels": {"字段1": "值1", "字段2": "值2", "字段3": "值3"}, "annotations": {"desc": "xxxx"}, "startsAt": "2023-02-09T09:58:45+08:00", "endsAt": "2023-02-09T10:00:45+08:00", "generatorURL": "http://1.1.1.1", "fingerprint": "12345"},{"status": "firing", "labels": {"字段1": "值1", "字段2": "值2", "字段3": "值3"}, "annotations": {"desc": "xxxx"}, "startsAt": "2023-02-09T09:58:45+08:00", "endsAt": "2023-02-09T10:00:45+08:00", "generatorURL": "http://1.1.1.1", "fingerprint": "12345"},{"status": "firing", "labels": {"字段1": "值1", "字段2": "值2", "字段3": "值3"}, "annotations": {"desc": "xxxx"}, "startsAt": "2023-02-09T09:58:45+08:00", "endsAt": "2023-02-09T10:00:45+08:00", "generatorURL": "http://1.1.1.1", "fingerprint": "12345"}], "groupLabels": {"字段1": "值1"}, "commonLabels": {"字段1": "值1", "字段2"}, "commonAnnotations": {"desc": "xxxx"}, "externalURL": "http://prometheus:9093", "version": "4", "truncatedAlerts": 0}'
告警恢复之后，对应的status字段会被置为resolved，只有alerts数组中所有告警都变为resolved状态，整条json的status才会置为resolved。
4 参数说明
- group_wait：当收到第一条告警时，延时该时间才进行发送，在此期间如果有其他告警被归并到相同group下，则届时会在json中一并发送给receiver。任何告警都会有此延时。
- group_interval：group_wait时间之后，每隔group_interval发送一次json给receiver
- repeat_interval：假如这个group没有任何变化，那么经过repeat_interval才会发送给receiver
4.1 举例
假设group_wait设置为30秒，group_interval设置为1分钟，repeat_interval设置为10分钟
- 10:00:00（t0）接收到第一条告警，10:00:20接收到第二条告警，则在10:00:30（t0+group_wait）会发送第一条json如下：
{"receiver": "email", "status": "firing", "alerts": [{"status": "firing", "labels": {"字段1": "值1", "字段2": "值2", "字段3": "值3"}...},{"status": "firing", "labels": {"字段1": "值1", "字段2": "值2", "字段3": "值3"}...}], ...}
- 10:00:40产生第三条告警，则在10:01:30（t0+group_wait+group_interval）会发送第二条json如下：
{"receiver": "email", "status": "firing", "alerts": [{"status": "firing", "labels": {"字段1": "值1", "字段2": "值2", "字段3": "值3"}...},{"status": "firing", "labels": {"字段1": "值1", "字段2": "值2", "字段3": "值3"}...},{"status": "firing", "labels": {"字段1": "值1", "字段2": "值2", "字段3": "值3"}...}], ...}
- 在10:01:40第一条告警恢复了，则10:02:30（t0+group_wait+group_interval*2）发送第三条json如下：
{"receiver": "email", "status": "firing", "alerts": [{"status": "resolve", "labels": {"字段1": "值1", "字段2": "值2", "字段3": "值3"}...},{"status": "firing", "labels": {"字段1": "值1", "字段2": "值2", "字段3": "值3"}...},{"status": "firing", "labels": {"字段1": "值1", "字段2": "值2", "字段3": "值3"}...}], ...}
- 在10:02:40另外两条告警也恢复了，则10:03:30（t0+group_wait+group_interval*3）发送第四条json如下：
{"receiver": "email", "status": "resolve", "alerts": [{"status": "resolve", "labels": {"字段1": "值1", "字段2": "值2", "字段3": "值3"}...},{"status": "resolve", "labels": {"字段1": "值1", "字段2": "值2", "字段3": "值3"}...}], ...}
假如10:00:30发送第一条json之后，2、3、4步骤都没有发生，且告警一直没有恢复，则10:10:30（t0+repeat_interval）会重复发送第一条json。