如何将 CloudWatch 警报配置为每 X 分钟评估一次

Question

我想将 CloudWatch 警报配置为：

• 对 ApplicationRequestsTotal 指标的最后 30 分钟求和每 30 分钟一次
• 总和等于 0 时报警

我已将自定义 CloudWatch ApplicationRequestsTotal 指标配置为每 60 秒为我的服务发出一次。

我已将警报配置为：

{
    "MetricAlarms": [
        {
            "AlarmName": "radio-silence-alarm",
            "AlarmDescription": "Alarm if 0 or less requests are received for 1 consecutive period(s) of 30 minutes.",
            "ActionsEnabled": true,
            "OKActions": [],
            "InsufficientDataActions": [],
            "MetricName": "ApplicationRequestsTotal",
            "Namespace": "AWS/ElasticBeanstalk",
            "Statistic": "Sum",
            "Dimensions": [
                {
                    "Name": "EnvironmentName",
                    "Value": "service-environment"
                }
            ],
            "Period": 1800,
            "EvaluationPeriods": 1,
            "Threshold": 0.0,
            "ComparisonOperator": "LessThanOrEqualToThreshold",
            "TreatMissingData": "missing"
        }
    ],
    "CompositeAlarms": []
}

我已经设置了很多这样的警报，每个警报似乎都是：

• 对过去 30 分钟的 ApplicationRequestsTotal 指标求和一次每分钟

例如，此服务在上午 8:36 开始获得 0 ApplicationRequestsTotal，并在上午 9:06 CloudWatch 触发了警报。

上述时间段的 aws cloudwatch describe-alarm-history：

{
    "AlarmName": "radio-silence-alarm",
    "AlarmType": "MetricAlarm",
    "Timestamp": "2021-09-29T09:06:37.929000+00:00",
    "HistoryItemType": "StateUpdate",
    "HistorySummary": "Alarm updated from OK to ALARM",
    "HistoryData": "{
       "version":"1.0",
       "oldState":{
          "stateValue":"OK",
          "stateReason":"Threshold Crossed: 1 datapoint [42.0 (22/09/21 08:17:00)] was not less than or equal to the threshold (0.0).",
          "stateReasonData":{
             "version":"1.0",
             "queryDate":"2021-09-22T08:47:37.930+0000",
             "startDate":"2021-09-22T08:17:00.000+0000",
             "statistic":"Sum",
             "period":1800,
             "recentDatapoints":[
                42.0
             ],
             "threshold":0.0,
             "evaluatedDatapoints":[
                {
                   "timestamp":"2021-09-22T08:17:00.000+0000",
                   "sampleCount":30.0,
                   "value":42.0
                }
             ]
          }
       },
       "newState":{
          "stateValue":"ALARM",
          "stateReason":"Threshold Crossed: 1 datapoint [0.0 (29/09/21 08:36:00)] was less than or equal to the threshold (0.0).",
          "stateReasonData":{
             "version":"1.0",
             "queryDate":"2021-09-29T09:06:37.926+0000",
             "startDate":"2021-09-29T08:36:00.000+0000",
             "statistic":"Sum",
             "period":1800,
             "recentDatapoints":[
                0.0
             ],
             "threshold":0.0,
             "evaluatedDatapoints":[
                {
                   "timestamp":"2021-09-29T08:36:00.000+0000",
                   "sampleCount":30.0,
                   "value":0.0
                }
             ]
          }
       }
    }"
}

我的哪些配置不正确？

Answer 1

这不是 Amazon CloudWatch 的工作方式。

在 CloudWatch 中创建警报时，您指定：

• 指标（例如 CPU 利用率，或者可能是发送到 CloudWatch 的自定义指标）
• 时间段（例如前 30 分钟）
• 一种聚合方法（例如Average、Sum、Count）

例如，如果在过去 30 分钟内超过指标的平均值，CloudWatch 可以触发警报。这被持续评估为滑动窗口。它确实不查看不同的 30 分钟块中的指标。

使用您的示例，只要指标总和在 前 30 分钟内为零，它就会持续发送警报。