Kubernetes(k8s)中文文件 Horizontal Pod Autoscaling_Kubernetes中文社群
阿新 • • 發佈:2018-12-27
Horizontal Pod Autoscaling
Horizontal Pod Autoscaling可以根據CPU使用率或應用自定義metrics自動擴充套件Pod數量(支援replication controller、deployment和replica set)。
- 控制管理器每隔30s(可以通過–horizontal-pod-autoscaler-sync-period修改)查詢metrics的資源使用情況
- 支援三種metrics型別
- 預定義metrics(比如Pod的CPU)以利用率的方式計算
- 自定義的Pod metrics,以原始值(raw value)的方式計算
- 自定義的object metrics
- 支援兩種metrics查詢方式:Heapster和自定義的REST API
- 支援多metrics
示例
# 建立pod和service $ kubectl run php-apache --image=gcr.io/google_containers/hpa-example --requests=cpu=200m --expose --port=80 service "php-apache" created deployment "php-apache" created # 建立autoscaler $ kubectl autoscale deployment php-apache --cpu-percent=50 --min=1 --max=10 deployment "php-apache" autoscaled $ kubectl get hpa NAME REFERENCE TARGET CURRENT MINPODS MAXPODS AGE php-apache Deployment/php-apache/scale 50% 0% 1 10 18s # 增加負載 $ kubectl run -i --tty load-generator --image=busybox /bin/sh Hit enter for command prompt $ while true; do wget -q -O- http://php-apache.default.svc.cluster.local; done # 過一會就可以看到負載升高了 $ kubectl get hpa NAME REFERENCE TARGET CURRENT MINPODS MAXPODS AGE php-apache Deployment/php-apache/scale 50% 305% 1 10 3m # autoscaler將這個deployment擴充套件為7個pod $ kubectl get deployment php-apache NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE php-apache 7 7 7 7 19m # 刪除剛才建立的負載增加pod後會發現負載降低,並且pod數量也自動降回1個 $ kubectl get hpa NAME REFERENCE TARGET CURRENT MINPODS MAXPODS AGE php-apache Deployment/php-apache/scale 50% 0% 1 10 11m $ kubectl get deployment php-apache NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE php-apache 1 1 1 1 27m
自定義metrics
使用方法
- 控制管理器開啟–horizontal-pod-autoscaler-use-rest-clients
- 在API Server Aggregator中註冊自定義的metrics API
注:可以參考k8s.io/metics開發自定義的metrics API server。
比如HorizontalPodAutoscaler保證每個Pod佔用50% CPU、1000pps以及10000請求/s:
HPA示例
apiVersion: autoscaling/v2alpha1 kind: HorizontalPodAutoscaler metadata: name: php-apache namespace: default spec: scaleTargetRef: apiVersion: apps/v1beta1 kind: Deployment name: php-apache minReplicas: 1 maxReplicas: 10 metrics: - type: Resource resource: name: cpu targetAverageUtilization: 50 - type: Pods pods: metricName: packets-per-second targetAverageValue: 1k - type: Object object: metricName: requests-per-second target: apiVersion: extensions/v1beta1 kind: Ingress name: main-route targetValue: 10k status: observedGeneration: 1 lastScaleTime: <some-time> currentReplicas: 1 desiredReplicas: 1 currentMetrics: - type: Resource resource: name: cpu currentAverageUtilization: 0 currentAverageValue: 0
參考:https://feisky.gitbooks.io/kubernetes/concepts/autoscaling.html