无法为podReadyPercentage指标创建MetricAlert的问题求助

问题 #

尝试用以下PowerShell脚本创建Azure Metric Alert时，报错提示找不到podReadyPercentage指标：

Set-AzContext -Subscription "f0bXXXXXXX"

$action = Get-AzActionGroup -ResourceGroupName gze-actgrp-pd-rgp-001 -Name UWDevOps_PD
$actionID = New-AzActionGroup -ActionGroupId $action.id

#Get-AzMetricDefinition -ResourceId "/subscriptions/9ca9XXXXX/resourcegroups/gze-pdi203-pd1-rgp-001/providers/Microsoft.ContainerService/managedClusters/gze-pdi203-pd1-aks-isostr-001"

$dim = New-AzMetricAlertRuleV2DimensionSelection -DimensionName "Kubernetes namespace" -ValuesToInclude "dv1"
$severity = 1
$RGObject = "gze-npi203-np1-rgp-001"
$ResourceId = "/subscriptions/9caXXXXXXX/resourcegroups/gze-npi203-np1-rgp-001/providers/Microsoft.ContainerService/managedClusters/gze-npi203-np1-aks-isostr-001"

$criteria = New-AzMetricAlertRuleV2Criteria -MetricName "podReadyPercentage" -DimensionSelection $dim `
-TimeAggregation average -Operator LessThan `
-Threshold 50

Set-AzContext -Subscription "921XXXX" # subID of the GZ-NP-IT-203-AKSISDUWSYS

Add-AzMetricAlertRuleV2 -Name "UWS-AKS203-ISOSTR-DV1-[Sev0-Critical]-Pods-Ready-Percentage less than 50-V2-CT" -ResourceGroupName $RGObject `
-WindowSize 01:00:00 -Frequency 01:00:00 `
-TargetResourceId $ResourceId -Condition $criteria `
-ActionGroup $actionID `
-Severity $severity

报错详情：

Add-AzMetricAlertRuleV2 : Exception type: ErrorResponseException, Message: Couldn't find a metric named podReadyPercentage. Make sure the name is correct. Activity ID: 192c5e83-2b8a-4cd3-861b-da8dd2da8c1f., Code: BadRequest, Status code:BadRequest, Reason phrase: BadRequest
At line:1 char:1
Add-AzMetricAlertRuleV2 -Name "UWS-AKS203-ISOSTR-DV1-[Sev0-Critical]- ...

• CategoryInfo : CloseError: (:) [Add-AzMetricAlertRuleV2], PSInvalidOperationException + FullyQualifiedErrorId : Microsoft.Azure.Commands.Insights.Alerts.AddAzureRmMetricAlertRuleV2Command

已知podReadyPercentage是官方文档中列出的合法指标，但无法定位问题所在。

排查与解决步骤 #

• 启用Container Insights自定义指标：podReadyPercentage属于Container Insights的自定义指标，需先在目标AKS集群上开启自定义指标收集功能，否则指标不会生成。
• 验证指标存在性：取消注释脚本中的Get-AzMetricDefinition命令，替换为目标集群的ResourceId，执行以下命令确认指标是否存在：

  Get-AzMetricDefinition -ResourceId "/subscriptions/9caXXXXXXX/resourcegroups/gze-npi203-np1-rgp-001/providers/Microsoft.ContainerService/managedClusters/gze-npi203-np1-aks-isostr-001" | Where-Object {$_.Name.Value -eq "podReadyPercentage"}
  

• 指定指标命名空间：podReadyPercentage的指标命名空间为container.azm.ms，创建告警规则时必须指定该命名空间，否则无法识别指标。修改New-AzMetricAlertRuleV2Criteria命令：

  $criteria = New-AzMetricAlertRuleV2Criteria -MetricName "podReadyPercentage" -MetricNamespace "container.azm.ms" -DimensionSelection $dim `
  -TimeAggregation average -Operator LessThan `
  -Threshold 50
  

• 修正维度名称大小写：Container Insights的指标维度名称区分大小写，正确维度名称为kubernetes namespace（全小写），修改维度定义：

  $dim = New-AzMetricAlertRuleV2DimensionSelection -DimensionName "kubernetes namespace" -ValuesToInclude "dv1"
  

• 确认订阅与权限：确保Set-AzContext -Subscription "921XXXX"命令已正确切换到目标订阅，且执行账号对AKS集群拥有Monitoring Contributor及以上权限。

内容的提问来源于stack exchange，提问作者kiruthiga