Kubernetes AWS Cloudwatch适配器未获取EKS HPA自动缩放的自定义指标值 [英] Kubernetes AWS Cloudwatch adapter not fetching custom metric value for EKS HPA autoscaling

问题描述

我正在尝试通过Kubernetes Cloudwatch适配器基于自定义Cloudwatch指标启用AWS EKS自动缩放.我已将自定义指标推送到AWS Cloudwatch，并验证它们是否出现在Cloudwatch控制台中以及是否可以使用boto3客户端get_metric_data检索到.这是我用来将自定义指标发布到Cloudwatch的代码:

I'm trying to enable AWS EKS autoscaling based on a custom Cloudwatch metric via the Kubernetes Cloudwatch adapter. I have pushed custom metrics to AWS Cloudwatch, and validated they appear in Cloudwatch console as well as are retrievable using the boto3 client get_metric_data. This is the code I use to publish my custom metric to Cloudwatch:

import boto3
from datetime import datetime

client = boto3.client('cloudwatch')

cloudwatch_response = client.put_metric_data(
    Namespace='TestMetricNS',
    MetricData=[
        {
            'MetricName': 'TotalUnprocessed',
            'Timestamp': datetime.now(),
            'Value': 40,
            'Unit': 'Megabytes',
        }
    ]
)

我具有以下yaml文件，用于在kubernetes中建立外部指标和hpa自动缩放器:

I have the following yaml files for establishing the external metric and the hpa autoscaler in kubernetes:

extMetricCustom.yaml:

extMetricCustom.yaml:

apiVersion: metrics.aws/v1alpha1
kind: ExternalMetric
metadata:
  name: test-custom-metric
spec:
  name: test-custom-metric
  resource:
    resource: "deployment"
  queries:
    - id: sqs_test
      metricStat:
        metric:
          namespace: "TestMetricNS"
          metricName: "TotalUnprocessed"
        period: 60
        stat: Average
        unit: Megabytes
      returnData: true

hpaCustomMetric.yaml

hpaCustomMetric.yaml

kind: HorizontalPodAutoscaler
apiVersion: autoscaling/v2beta1
metadata:
  name: test-scaler
spec:
  scaleTargetRef:
    apiVersion: apps/v1beta1
    kind: Deployment
    name: sqs-consumer
  minReplicas: 1
  maxReplicas: 4
  metrics:
  - type: External
    external:
      metricName: test-custom-metric
      targetAverageValue: 2

当我评估Kubernetes Cloudwatch适配器是否正确获取我的自定义指标(kubectl get hpa)时，它始终显示该指标为0:

When I assess whether the Kubernetes Cloudwatch adapter is properly grabbing my custom metric (kubectl get hpa), it always displays that the metric is 0:

NAME          REFERENCE                 TARGETS     MINPODS   MAXPODS   REPLICAS   AGE
test-scaler   Deployment/sqs-consumer   0/2 (avg)   1         4         1          161m

如何根据Cloudwatch自定义指标正确地自动缩放?

How can I properly autoscale based off my Cloudwatch custom metric?

推荐答案

在带外与OP一起工作，并且当天晚些时候仍然打开该问题的选项卡，因此在此处发布结果以供所有人参考偶然发现了它.

Worked with OP on this out-of-band and still had the tab open for this question later in the day, so posting the outcome here for posterity for anyone that stumbles upon it.

此问题的根本原因是时区冲突.指标监控器基于当前"指标.指标，但指标生成器脚本的以下代码行在未指定时区的情况下生成时间戳，并且该时间戳也位于本地时区.

The root cause of the issue was a timezone conflict. The metrics monitor was based on "current" metrics, but the the following line from the metric generator script was producing time stamps without a timezone specified and also was in a local timezone.

            'Timestamp': datetime.now(),

因为没有数据"，对于当前时区(由于-X UTC偏移，仅过去X个小时的数据)，系统未启动缩放，因为有效值为"0"/nil/null.相反，可以指定UTC时间字符串以确保生成的度量标准是及时的:

Since there was "no data" for the current timezone (only data X hours in the past due to a -X UTC offset), the system did not initiate scaling because there was a value of "0"/nil/null effectively. Instead, a UTC time string can be specified to ensure the generated metrics are timely:

            'Timestamp': datetime.utcnow(),

次要考虑的是Kubernetes节点需要访问权才能从CloudWatch轮询指标.这是通过附加此政策节点的IAM角色:

A secondary consideration was that the Kubernetes Nodes need access to poll the metrics from CloudWatch. This is done by attaching this policy to the nodes's IAM role:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "cloudwatch:GetMetricData"
            ],
            "Resource": "*"
        }
    ]
}

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