如何在K8s（EKS）与prometheus-adapter中获取外部指标值

• AWS EKS集群，通过Helm安装v4.9.0版本的prometheus-adapter，用于暴露自定义指标（custom metrics）和外部指标（external metrics）供HPA（HorizontalPodAutoscaler）使用
• 当前问题：无法获取外部指标的数值

确认指标已注册 #

执行以下命令确认外部指标已存在于API资源列表中：

kubectl get --raw '/apis/external.metrics.k8s.io/v1beta1' | jq .

输出结果：

{
  "kind": "APIResourceList",
  "apiVersion": "v1",
  "groupVersion": "external.metrics.k8s.io/v1beta1",
  "resources": [
    {
      "name": "some_dummy_sqs_01",
      "singularName": "",
      "namespaced": true,
      "kind": "ExternalMetricValueList",
      "verbs": [
        "get"
      ]
    }
  ]
}

尝试过的API路径及对应错误 #

以下所有路径均无法成功获取指标值，返回错误如下：

• /apis/external.metrics.k8s.io/v1beta1/some_dummy_sqs_01 → 错误：Error from server (NotFound): the server could not find the requested resource
• /apis/external.metrics.k8s.io/v1beta1/namespaces/some_dummy_sqs_01 → 错误：Error from server (NotFound): the server could not find the requested resource
• /apis/external.metrics.k8s.io/v1beta1/namespaces//some_dummy_sqs_01 → 错误：Error from server (InternalError): Internal error occurred: unable to fetch metrics
• /apis/external.metrics.k8s.io/v1beta1/namespaces/*/some_dummy_sqs_01 → 错误：Error from server (InternalError): Internal error occurred: unable to fetch metrics
• /apis/external.metrics.k8s.io/v1beta1/namespaces/prometheus/some_dummy_sqs_01 → 错误：Error from server (InternalError): Internal error occurred: unable to fetch metrics

Prometheus-Adapter配置 #

当前使用的Helm values配置文件内容：

# prom-adapter-values.yaml

prometheus:
  url: http://prometheus-server
  port: 80

rules:
  default: false
  external:
    - seriesQuery: 'sqs_approximatenumberofmessages{queue!="",namespace!=""}'
      resources:
        namespaced: false
      name:
        matches: ""
        as: "some_dummy_sqs_01"
      metricsQuery: 'sum(rate(<<.Series>>[1m]) by (queue)'

内容的提问来源于stack exchange，提问作者hfm