1.HPA
HPA（Horizontal Pod Autoscaler）在k8s集群中用于POD水平自动伸缩，它是基于CPU和内存利用率对Deployment和Replicaset控制器中的pod数量进行自动扩缩容（除了CPU和内存利用率之外，也可以基于其他应程序提供的度量指标custom metrics进行自动扩缩容）。pod自动缩放不适用于无法缩放的对象，比如DaemonSets。HPA由Kubernetes API资源和控制器实现。资源决定了控制器的行为，控制器会周期性的获取CPU和内存利用率，并与目标值相比较后来调整replication controller或deployment中的副本数量。
HPA使用前提条件：
- 集群中部署了Metrics Server插件, 可以获取到Pod的CPU和内存利用率。
- Pod部署的Yaml文件中必须设置资源限制和资源请求。
1.1.安装metrics-server
metrics-server可以用来收集集群中的资源使用情况
https://github.com/kubernetes-sigs/metrics-server
参考
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# 安装git
[root@master ~]# yum install git -y
# 获取metrics-server, 注意使用的版本
[root@master ~]# git clone -b v0.3.6 https://github.com/kubernetes-incubator/metrics-server
# 修改deployment, 注意修改的是镜像和初始化参数
[root@master ~]# cd /root/metrics-server/deploy/1.8+/
[root@master 1.8+]# vim metrics-server-deployment.yaml
按图中添加下面选项
hostNetwork: true
image: registry.cn-hangzhou.aliyuncs.com/google_containers/metrics-server-amd64:v0.3.6
args:
- --kubelet-insecure-tls
- --kubelet-preferred-address-types=InternalIP,Hostname,InternalDNS,ExternalDNS,ExternalIP
安装
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# 获取metrics-server, 注意使用的版本
[root@k8s-master hpa]# git clone -b v0.3.6 https://github.com/kubernetes-incubator/metrics-server
# 修改deployment, 注意修改的是镜像和初始化参数
[root@k8s-master1 1.8+]# cd /k8s/module/hpa/metrics-server/deploy/1.8+
[root@k8s-master1 1.8+]# ll
total 28
-rw-r--r--. 1 root root 393 Dec 17 09:22 aggregated-metrics-reader.yaml
-rw-r--r--. 1 root root 308 Dec 17 09:22 auth-delegator.yaml
-rw-r--r--. 1 root root 329 Dec 17 09:22 auth-reader.yaml
-rw-r--r--. 1 root root 298 Dec 17 09:22 metrics-apiservice.yaml
-rw-r--r--. 1 root root 804 Dec 17 09:22 metrics-server-deployment.yaml
-rw-r--r--. 1 root root 291 Dec 17 09:22 metrics-server-service.yaml
-rw-r--r--. 1 root root 517 Dec 17 09:22 resource-reader.yaml
[root@master 1.8+]# vim metrics-server-deployment.yaml
# 按图中添加下面选项
hostNetwork: true
image: registry.cn-hangzhou.aliyuncs.com/google_containers/metrics-server-amd64:v0.3.6
args:
- --kubelet-insecure-tls
- --kubelet-preferred-address-types=InternalIP,Hostname,InternalDNS,ExternalDNS,ExternalIP
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# 安装metrics-server
[root@k8s-master1 1.8+]# kubectl apply -f ./
clusterrole.rbac.authorization.k8s.io/system:aggregated-metrics-reader created
Warning: rbac.authorization.k8s.io/v1beta1 ClusterRoleBinding is deprecated in v1.17+, unavailable in v1.22+; use rbac.authorization.k8s.io/v1 ClusterRoleBinding
clusterrolebinding.rbac.authorization.k8s.io/metrics-server:system:auth-delegator created
Warning: rbac.authorization.k8s.io/v1beta1 RoleBinding is deprecated in v1.17+, unavailable in v1.22+; use rbac.authorization.k8s.io/v1 RoleBinding
rolebinding.rbac.authorization.k8s.io/metrics-server-auth-reader created
Warning: apiregistration.k8s.io/v1beta1 APIService is deprecated in v1.19+, unavailable in v1.22+; use apiregistration.k8s.io/v1 APIService
apiservice.apiregistration.k8s.io/v1beta1.metrics.k8s.io created
serviceaccount/metrics-server created
deployment.apps/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
# 查看pod运行情况
[root@k8s-master 1.8+]# kubectl get pod -n kube-system
NAME READY STATUS RESTARTS AGE
...
metrics-server-9c7dc6fdc-mgl6r 1/1 Running 0 30s
# 使用kubectl top node 查看资源使用情况
[root@k8s-master1 1.8+]# kubectl top node
NAME CPU(cores) CPU% MEMORY(bytes) MEMORY%
k8s-master1 344m 8% 3791Mi 24%
k8s-master2 283m 7% 2373Mi 15%
k8s-master3 332m 8% 2202Mi 13%
k8s-node1 250m 6% 1189Mi 7%
k8s-node2 258m 6% 1270Mi 8%
k8s-node3 267m 6% 1173Mi 7%
k8s-node4 240m 6% 1197Mi 7%
[root@k8s-master1 1.8+]# kubectl top pod -n kube-system
NAME CPU(cores) MEMORY(bytes)
calico-kube-controllers-558995777d-l8lpr 3m 27Mi
calico-node-6l5w2 21m 150Mi
calico-node-g68dm 22m 142Mi
calico-node-qt82k 29m 150Mi
calico-node-rvtbg 34m 146Mi
calico-node-tn2xj 19m 146Mi
calico-node-wnjhd 24m 149Mi
calico-node-wt5cb 23m 149Mi
coredns-7f89b7bc75-h2htb 2m 16Mi
coredns-7f89b7bc75-k5phr 2m 16Mi
etcd-k8s-master1 19m 192Mi
etcd-k8s-master2 19m 193Mi
etcd-k8s-master3 21m 192Mi
kube-apiserver-k8s-master1 35m 453Mi
kube-apiserver-k8s-master2 35m 427Mi
kube-apiserver-k8s-master3 34m 438Mi
kube-controller-manager-k8s-master1 1m 29Mi
kube-controller-manager-k8s-master2 1m 27Mi
kube-controller-manager-k8s-master3 7m 61Mi
kube-proxy-5pjpd 1m 20Mi
kube-proxy-86vds 1m 21Mi
kube-proxy-cv28h 1m 18Mi
kube-proxy-mmbj6 1m 17Mi
kube-proxy-s9lhm 1m 19Mi
kube-proxy-tvt2z 1m 18Mi
kube-proxy-w7j6l 1m 21Mi
kube-scheduler-k8s-master1 2m 23Mi
kube-scheduler-k8s-master2 2m 23Mi
kube-scheduler-k8s-master3 2m 27Mi
metrics-server-67bd88dc86-dk2w9 1m 14Mi
# 至此,metrics-server安装完成
1.2.常用命令
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# 使用kubectl top node 查看资源使用情况
[root@master 1.8+]# kubectl top node
[root@k8s-master hpa]# kubectl describe node k8s-node1
# 查看pod资源
[root@master 1.8+]# kubectl top pod -n kube-system
# 查看hpa
[root@k8s-master hpa]# kubectl get hpa -n dev
[root@k8s-master ~]# kubectl get deploy -n dev -w
