在 Kubernetes 中可以手动通过 kubectl scale 命令或通过修改 replicas 数量,可以实现 Pod 的扩容或缩容。Kubernetes 中还提供了 HPA(Horizontal Pod Autoscaling) 功能,可以根据当前负载的变化情况自动触发水平扩展或缩容的行为,从而合理的使用资源。从 Kubernetes v1.8 开始,资源使用情况的度量(如容器的 CPU 和内存使用)可以通过 Metrics API 获取,HPA 使用这些 metics 信息来实现动态伸缩。
- https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale/
- https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale-walkthrough/
拉取镜像
$ touch pull_k8s_images.sh #!/bin/bash images=(metrics-server-amd64:v0.3.1) for imageName in ${images[@]} ; do docker pull anjia0532/google-containers.$imageName docker tag anjia0532/google-containers.$imageName k8s.gcr.io/$imageName docker rmi anjia0532/google-containers.$imageName done $ sh touch pull_k8s_images.sh
部署 metrics-server
$ git clone https://github.com/kubernetes-incubator/metrics-server.git $ cd metrics-server $ kubectl create -f deploy/1.8+/ clusterrole.rbac.authorization.k8s.io/system:aggregated-metrics-reader created clusterrolebinding.rbac.authorization.k8s.io/metrics-server:system:auth-delegator created rolebinding.rbac.authorization.k8s.io/metrics-server-auth-reader created apiservice.apiregistration.k8s.io/v1beta1.metrics.k8s.io created serviceaccount/metrics-server created deployment.extensions/metrics-server created service/metrics-server created clusterrole.rbac.authorization.k8s.io/system:metrics-server created clusterrolebinding.rbac.authorization.k8s.io/system:metrics-server created
上述可能还会提示拉取不到镜像,由于配置了 imagePullPolicy: Always,可以注释掉
vi metrics-server-deployment.yaml --- apiVersion: v1 kind: ServiceAccount metadata: name: metrics-server namespace: kube-system --- apiVersion: extensions/v1beta1 kind: Deployment metadata: name: metrics-server namespace: kube-system labels: k8s-app: metrics-server spec: selector: matchLabels: k8s-app: metrics-server template: metadata: name: metrics-server labels: k8s-app: metrics-server spec: serviceAccountName: metrics-server volumes: # mount in tmp so we can safely use from-scratch images and/or read-only containers - name: tmp-dir emptyDir: {} containers: - name: metrics-server image: k8s.gcr.io/metrics-server-amd64:v0.3.1 # imagePullPolicy: Always volumeMounts: - name: tmp-dir mountPath: /tmp
执行查看
$ kubectl apply -f metrics-server-deployment.yaml $ kubectl get pod,svc -n kube-system NAME READY STATUS RESTARTS AGE pod/coredns-576cbf47c7-d6tm2 1/1 Running 0 14d pod/coredns-576cbf47c7-zgdsx 1/1 Running 0 14d pod/etcd-kubernetes-master 1/1 Running 0 14d pod/kube-apiserver-kubernetes-master 1/1 Running 0 14d pod/kube-controller-manager-kubernetes-master 1/1 Running 1 14d pod/kube-proxy-dz4fh 1/1 Running 0 14d pod/kube-proxy-qh9b5 1/1 Running 0 14d pod/kube-proxy-x8clc 1/1 Running 0 14d pod/kube-scheduler-kubernetes-master 1/1 Running 1 14d pod/kubernetes-dashboard-77fd78f978-qp626 1/1 Running 0 14d pod/metrics-server-79f8f467b5-6l5wh 1/1 Running 0 10m pod/tiller-deploy-7788856dfb-7kkw7 1/1 Running 0 11d pod/traefik-ingress-controller-qjnc6 1/1 Running 0 12d pod/traefik-ingress-controller-rwxr6 1/1 Running 0 12d pod/weave-net-j9s27 2/2 Running 0 6d11h pod/weave-net-p22s2 2/2 Running 0 6d11h pod/weave-net-vnq7p 2/2 Running 0 6d11h NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE service/kube-dns ClusterIP 10.96.0.10 <none> 53/UDP,53/TCP 14d service/kubernetes-dashboard NodePort 10.103.60.159 <none> 443:32151/TCP 14d service/metrics-server ClusterIP 10.110.180.222 <none> 443/TCP 42m service/tiller-deploy ClusterIP 10.103.123.198 <none> 44134/TCP 11d service/traefik-ingress-service ClusterIP 10.105.18.62 <none> 80/TCP,8080/TCP 12d service/traefik-web-ui ClusterIP 10.102.207.196 <none> 80/TCP 12d
配置 HPA
vi vi nginx-deployment-hpa.yaml apiVersion: autoscaling/v1 kind: HorizontalPodAutoscaler metadata: name: nginx-deployment-hpa namespace: default spec: maxReplicas: 10 minReplicas: 4 scaleTargetRef: kind: Deployment name: nginx-deployment targetCPUUtilizationPercentage: 50 # CPUUtilizationPercentage 是一个平均值,即 Pod 所有副本自身的 CPU 利用率的平均值。
备注:Kubernetes v1.2 版本中 HPA 升级为稳定版本(apiVersion: autoscaling/v1),等同于 kubectl autoscale deployment nginx-deployment--cpu-percent=50 --min=4 --max=10
执行查看
kubectl apply -f nginx-deployment-hpa.yaml $ kubectl get hpa NAME REFERENCE TARGETS MINPODS MAXPODS REPLICAS AGE nginx-deployment-hpa Deployment/nginx-deployment <unknown>/50% 4 10 0 11s
REFER:
https://kubernetes.io/docs/reference/generated/kubectl/kubectl-commands#autoscale
https://github.com/kubernetes-incubator/metrics-server
https://github.com/stefanprodan/k8s-prom-hpa
http://blog.51cto.com/ylw6006/2114338
https://www.kubernetes.org.cn/4664.html