Kubernetes K8S HPA-无法从外部度量API获取度量
我试图让卡夫卡主题滞后到普罗米修斯,最后到APIServer,以便为我的应用程序使用外部度量HPA 我收到错误没有从外部度量API返回度量Kubernetes K8S HPA-无法从外部度量API获取度量,kubernetes,prometheus,k3s,Kubernetes,Prometheus,K3s,我试图让卡夫卡主题滞后到普罗米修斯,最后到APIServer,以便为我的应用程序使用外部度量HPA 我收到错误没有从外部度量API返回度量 70m Warning FailedGetExternalMetric horizontalpodautoscaler/kafkademo-hpa unable to get external metric default/kafka_lag_metric_sm0ke/&LabelSelector{MatchLa
70m Warning FailedGetExternalMetric horizontalpodautoscaler/kafkademo-hpa unable to get external metric default/kafka_lag_metric_sm0ke/&LabelSelector{MatchLabels:map[string]string{topic: prices,},MatchExpressions:[]LabelSelectorRequirement{},}: no metrics returned from external metrics API
66m Warning FailedComputeMetricsReplicas horizontalpodautoscaler/kafkademo-hpa invalid metrics (1 invalid out of 1), first error is: failed to get external metric kafka_lag_metric_sm0ke: unable to get external metric default/kafka_lag_metric_sm0ke/&LabelSelector{MatchLabels:map[string]string{topic: prices,},MatchExpressions:[]LabelSelectorRequirement{},}: no metrics returned from external metrics API
即使在查询外部API时我可以看到以下输出,这种情况也会发生:
kubectl get --raw /apis/external.metrics.k8s.io/v1beta1 | jq
{
"kind": "APIResourceList",
"apiVersion": "v1",
"groupVersion": "external.metrics.k8s.io/v1beta1",
"resources": [
{
"name": "kafka_lag_metric_sm0ke",
"singularName": "",
"namespaced": true,
"kind": "ExternalMetricValueList",
"verbs": [
"get"
]
}
]
}
以下是设置:
- 卡夫卡:v2.7.0
- 普罗米修斯:v2.26.0
- 普罗米修斯适配器:v0.8.3
rules:
external:
- seriesQuery: 'kafka_consumergroup_group_lag{topic="prices"}'
resources:
template: <<.Resource>>
name:
as: "kafka_lag_metric_sm0ke"
metricsQuery: 'avg by (topic) (round(avg_over_time(<<.Series>>{<<.LabelMatchers>>}[1m])))'
HPA信息
kubectl describe hpa kafkademo-hpa
Name: kafkademo-hpa
Namespace: default
Labels: <none>
Annotations: <none>
CreationTimestamp: Sat, 17 Apr 2021 20:01:29 +0300
Reference: Deployment/kafkademo
Metrics: ( current / target )
"kafka_lag_metric_sm0ke" (target value): <unknown> / 5
Min replicas: 3
Max replicas: 12
Deployment pods: 3 current / 0 desired
Conditions:
Type Status Reason Message
---- ------ ------ -------
AbleToScale True SucceededGetScale the HPA controller was able to get the target's current scale
ScalingActive False FailedGetExternalMetric the HPA was unable to compute the replica count: unable to get external metric default/kafka_lag_metric_sm0ke/&LabelSelector{MatchLabels:map[string]string{topic: prices,},MatchExpressions:[]LabelSelectorRequirement{},}: no metrics returned from external metrics API
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Warning FailedComputeMetricsReplicas 70m (x335 over 155m) horizontal-pod-autoscaler invalid metrics (1 invalid out of 1), first error is: failed to get external metric kafka_lag_metric_sm0ke: unable to get external metric default/kafka_lag_metric_sm0ke/&LabelSelector{MatchLabels:map[string]string{topic: prices,},MatchExpressions:[]LabelSelectorRequirement{},}: no metrics returned from external metrics API
Warning FailedGetExternalMetric 2m30s (x366 over 155m) horizontal-pod-autoscaler unable to get external metric default/kafka_lag_metric_sm0ke/&LabelSelector{MatchLabels:map[string]string{topic: prices,},MatchExpressions:[]LabelSelectorRequirement{},}: no metrics returned from external metrics API
我可以看到“items”字段为空。这是什么意思
我似乎不理解的是幕后发生的一连串事件
好吧,事情就是这样这是否正确?
- prometheus适配器查询prometheus,执行seriesQuery,计算metricsQuery并创建“kafka\u lag\u metric\u sm0ke”
- 它向api服务器注册一个端点以获取外部指标
- API服务器将根据该端点定期更新其统计信息
- HPA从API服务器检查“kafka_lag_metric_sm0ke”,并根据提供的值执行缩放
我似乎也不明白名称空间在这一切中的重要性。我可以看到stat是名称空间的。这是否意味着每个命名空间将有1个stat?这有什么意义呢?长期以来,我都是在问完问题后再回答自己的问题,下面是上述配置的错误之处 该错误存在于普罗米修斯适配器yaml中:
rules:
external:
- seriesQuery: 'kafka_consumergroup_group_lag{topic="prices"}'
resources:
template: <<.Resource>>
name:
as: "kafka_lag_metric_sm0ke"
metricsQuery: 'avg by (topic) (round(avg_over_time(<<.Series>>{<<.LabelMatchers>>}[1m])))'
我仍然不确定它为什么会起作用。我知道在这种情况下,
将被不生成有效查询的内容所取代,但我不知道它是什么
kubectl get --raw /apis/external.metrics.k8s.io/v1beta1/namespaces/default/kafka_lag_metric_sm0ke |jq
{
"kind": "ExternalMetricValueList",
"apiVersion": "external.metrics.k8s.io/v1beta1",
"metadata": {},
"items": []
}
rules:
external:
- seriesQuery: 'kafka_consumergroup_group_lag{topic="prices"}'
resources:
template: <<.Resource>>
name:
as: "kafka_lag_metric_sm0ke"
metricsQuery: 'avg by (topic) (round(avg_over_time(<<.Series>>{<<.LabelMatchers>>}[1m])))'
kubectl get --raw /apis/external.metrics.k8s.io/v1beta1/namespaces/default/kafka_lag_metric_sm0ke |jq
{
"kind": "ExternalMetricValueList",
"apiVersion": "external.metrics.k8s.io/v1beta1",
"metadata": {},
"items": [
{
"metricName": "kafka_lag_metric_sm0ke",
"metricLabels": {
"topic": "prices"
},
"timestamp": "2021-04-21T16:55:18Z",
"value": "0"
}
]
}