16-Kubernetes-Pod控制器详解-Horizontal Pod Autoscaler(HPA)
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Pod控制器详解-Horizontal Pod Autoscaler
前言
- 本篇来学习Pod控制器-Horizontal Pod Autoscaler
Horizontal Pod Autoscaler
HPA可以获取每个Pod利用率,然后和HPA中定义的指标进行对比,同时计算出需要伸缩的具体值,最后实现Pod的数量的调整。其实HPA与之前的Deployment一样,也属于一种Kubernetes资源对象,它通过追踪分析RC控制的所有目标Pod的负载变化情况,来确定是否需要针对性地调整目标Pod的副本数,这是HPA的实现原理。
安装metrics-server
# 安装git
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 ~]# 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metrics-server
[root@master 1.8+]# kubectl apply -f ./
clusterrole.rbac.authorization.k8s.io/system:aggregated-metrics-reader unchanged
clusterrolebinding.rbac.authorization.k8s.io/metrics-server:system:auth-delegator unchanged
rolebinding.rbac.authorization.k8s.io/metrics-server-auth-reader unchanged
apiservice.apiregistration.k8s.io/v1beta1.metrics.k8s.io unchanged
serviceaccount/metrics-server unchanged
deployment.apps/metrics-server created
service/metrics-server unchanged
clusterrole.rbac.authorization.k8s.io/system:metrics-server unchanged
clusterrolebinding.rbac.authorization.k8s.io/system:metrics-server unchanged
# 查看pod
[root@master 1.8+]# kubectl get pod -n kube-system
NAME READY STATUS RESTARTS AGE
metrics-server-6b976979db-jwqms 1/1 Running 0 8m35s
# 查看资源使用情况
[root@master 1.8+]# kubectl top node
NAME CPU(cores) CPU% MEMORY(bytes) MEMORY%
master 158m 7% 1020Mi 59%
node1 35m 1% 423Mi 24%
node2 47m 2% 408Mi 23%
node3 55m 2% 440Mi 25%
[root@master 1.8+]# kubectl top pod -n kube-system
NAME CPU(cores) MEMORY(bytes)
coredns-6955765f44-rb6mz 5m 5Mi
etcd-master 17m 76Mi
kube-apiserver-master 45m 321Mi
kube-controller-manager-master 34m 57Mi
kube-flannel-ds-m8scb 3m 41Mi
kube-flannel-ds-nstpr 2m 49Mi
kube-flannel-ds-v46tp 2m 23Mi
kube-proxy-4r8jh 1m 14Mi
kube-proxy-5v5qn 1m 13Mi
kube-proxy-s4fw2 1m 15Mi
kube-proxy-tk5bx 1m 22Mi
kube-scheduler-master 4m 25Mi
metrics-server-6b976979db-jwqms 1m 11Mi
- metrics-server-deployment.yaml 文件修改后如下:
---
apiVersion: v1
kind: ServiceAccount
metadata:
name: metrics-server
namespace: kube-system
---
apiVersion: apps/v1
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:
hostNetwork: true
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: registry.cn-hangzhou.aliyuncs.com/google_containers/metrics-server-amd64:v0.3.6
imagePullPolicy: Always
args:
- --kubelet-insecure-tls
- --kubelet-preferred-address-types=InternalIP,Hostname,InternalDNS,ExternalDNS,ExternalIP
volumeMounts:
- name: tmp-dir
mountPath: /tmp
准备deployment和servie
创建pc-hpa-pod.yaml文件,内容如下:
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx
namespace: dev
spec:
strategy: # 策略
type: RollingUpdate # 滚动更新策略
replicas: 1
selector:
matchLabels:
app: nginx-pod
template:
metadata:
labels:
app: nginx-pod
spec:
containers:
- name: nginx
image: nginx:1.17.1
resources: # 资源配额
limits: # 限制资源(上限)
cpu: "1" # CPU限制,单位是core数
requests: # 请求资源(下限)
cpu: "100m" # CPU限制,单位是core数
# 创建deployment
[root@master 1.8+]# kubectl run nginx --image=nginx:1.17.1 --requests=cpu=100m -n dev
# 创建service
[root@master 1.8+]# kubectl expose deployment nginx --type=NodePort --port=80 -n dev
service/nginx exposed
# 查看
[root@master 1.8+]# kubectl get deployment,pod,svc -n dev
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/nginx 1/1 1 1 20s
NAME READY STATUS RESTARTS AGE
pod/nginx-778cb5fb7b-2q6zf 1/1 Running 0 19s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/nginx NodePort 10.110.69.156 <none> 80:31898/TCP 8s
部署HPA
创建pc-hpa.yaml文件,内容如下:
apiVersion: autoscaling/v1
kind: HorizontalPodAutoscaler
metadata:
name: pc-hpa
namespace: dev
spec:
minReplicas: 1 #最小pod数量
maxReplicas: 10 #最大pod数量
targetCPUUtilizationPercentage: 3 # CPU使用率指标
scaleTargetRef: # 指定要控制的nginx信息
apiVersion: /v1
kind: Deployment
name: nginx
# 创建hpa
[root@master ~]# kubectl create -f pc-hpa.yaml
horizontalpodautoscaler.autoscaling/pc-hpa created
# 查看hpa
[root@master ~]# kubectl get hpa -n dev
NAME REFERENCE TARGETS MINPODS MAXPODS REPLICAS AGE
pc-hpa Deployment/nginx <unknown>/3% 1 10 0 11m
测试
使用压测工具对service地址192.168.96.100:31898
进行压测,然后通过控制台查看hpa和pod的变化
# hpa变化
[root@master ~]# kubectl get hpa -n dev -w
# deployment变化
[root@master ~]# kubectl get deployment -n dev -w
# pod变化
[root@master ~]# kubectl get pods -n dev -w
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