kubernetes - 默认GKE Pod上的CPU节流

Question

我刚刚在GKE上创建了具有2个n1-standard-2节点的集群，并使用官方的helm安装了prometheusOperator。

普罗米修斯似乎工作正常，但我正在收到这样的警报:

message: 33% throttling of CPU in namespace kube-system for container metrics-server in pod metrics-server-v0.3.1-8d4c5db46-zddql.
22 minutes agocontainer: metrics-serverpod: metrics-server-v0.3.1-8d4c5db46-zddql
message: 35% throttling of CPU in namespace kube-system for container heapster-nanny in pod heapster-v1.6.1-554bfbc7d-tg6fm.
an hour agocontainer: heapster-nannypod: heapster-v1.6.1-554bfbc7d-tg6fm
message: 77% throttling of CPU in namespace kube-system for container prometheus-to-sd in pod prometheus-to-sd-789b2.
20 hours agocontainer: prometheus-to-sdpod: prometheus-to-sd-789b2
message: 45% throttling of CPU in namespace kube-system for container heapster in pod heapster-v1.6.1-554bfbc7d-tg6fm.
20 hours agocontainer: heapsterpod: heapster-v1.6.1-554bfbc7d-tg6fm
message: 38% throttling of CPU in namespace kube-system for container default-http-backend in pod l7-default-backend-8f479dd9-9n77b.

所有这些Pod都是默认GKE安装的一部分，我尚未对其进行任何修改。我相信它们是我尚未真正尝试使用的某些Google云工具的一部分。

我的节点并不是真的很繁重:

kubectl top node                                           
NAME                                      CPU(cores)   CPU%   MEMORY(bytes)   MEMORY%   
gke-psi-cluster-01-pool-1-d5650403-cl4g   230m         11%    2973Mi          52%       
gke-psi-cluster-01-pool-1-d5650403-xn35   146m         7%     2345Mi          41%  

这是我的普罗米修斯 Helm 配​​置:

alertmanager:
  alertmanagerSpec:
    storage:
      volumeClaimTemplate:
        spec:
          accessModes:
          - ReadWriteOnce
          resources:
            requests:
              storage: 5Gi
  config:
    global:
      resolve_timeout: 5m
    receivers:
    - name: "null"
    - name: slack_k8s
      slack_configs:
      - api_url: REDACTED
        channel: '#k8s'
        send_resolved: true
        text: |-
          {{ range .Alerts }}
            {{- if .Annotations.summary }}
            *{{ .Annotations.summary }}*
            {{- end }}
            *Severity* : {{ .Labels.severity }}
            {{- if .Labels.namespace }}
            *Namespace* : {{ .Labels.namespace }}
            {{- end }}
            {{- if .Annotations.description }}
            {{ .Annotations.description }}
            {{- end }}
            {{- if .Annotations.message }}
            {{ .Annotations.message }}
            {{- end }}
          {{ end }}
        title: '{{ (index .Alerts 0).Labels.alertname }}'
        title_link: https://karma.REDACTED?q=alertname%3D{{ (index .Alerts 0).Labels.alertname
          }}
    route:
      group_by:
      - alertname
      - job
      group_interval: 5m
      group_wait: 30s
      receiver: slack_k8s
      repeat_interval: 6h
      routes:
      - match:
          alertname: Watchdog
        receiver: "null"
      - match:
          alertname: KubeAPILatencyHigh
        receiver: "null"
  ingress:
    enabled: false
    hosts:
    - alertmanager.REDACTED
coreDns:
  enabled: false
grafana:
  adminPassword: REDACTED
  ingress:
    annotations:
      kubernetes.io/tls-acme: "true"
    enabled: true
    hosts:
    - grafana.REDACTED
    tls:
    - hosts:
      - grafana.REDACTED
      secretName: grafana-crt-secret
  persistence:
    enabled: true
    size: 5Gi
kubeControllerManager:
  enabled: true
kubeDns:
  enabled: true
kubeScheduler:
  enabled: true
nodeExporter:
  enabled: true
prometheus:
  ingress:
    enabled: false
    hosts:
    - prometheus.REDACTED
  prometheusSpec:
    additionalScrapeConfigs:
    - basic_auth:
        password: REDACTED
        username: prometheus
    retention: 30d
    ruleSelectorNilUsesHelmValues: false
    serviceMonitorSelectorNilUsesHelmValues: false
    storageSpec:
      volumeClaimTemplate:
        spec:
          accessModes:
          - ReadWriteOnce
          resources:
            requests:
              storage: 30Gi
prometheusOperator:
  createCustomResource: false

我发现了这个git问题 https://github.com/kubernetes-monitoring/kubernetes-mixin/issues/108
但是我不确定这是否适用于我的情况，因为这是默认的GKE pods 。
我想确保一切运行顺利，即使我还没有真正了解如何使用它，Stackdriver都能正确检索我的所有日​​志。

我应该修改kube系统中GKE默认部署的限制吗？在GKE上部署prometheusOperator有什么问题吗？

Answer 1

在浏览了许多链接之后，我认为我在这里理解了这个问题。

我认为这是您遇到的k8s问题。 [1]

Linux中的CFS配额似乎会影响所有容器化的云(包括Kubernetes)，您可以通过为集群添加更高的CPU限制或从容器中删除CPU限制来解决此问题。请在暂存环境中而不是在生产中直接进行测试。

祝你好运!

[1] https://github.com/kubernetes/kubernetes/issues/67577