从 v1.8 开始，资源使用情况的监控可以通过 Metrics API的形式获取，具体的组件为Metrics Server，用来替换之前的heapster，heapster从1.11开始逐渐被废弃。
Metrics-Server是集群核心监控数据的聚合器，从 Kubernetes1.8 开始，它作为一个 Deployment对象默认部署在由kube-up.sh脚本创建的集群中，如果是其他部署方式需要单独安装，或者咨询对应的云厂商。
Metrics API
介绍Metrics-Server之前，必须要提一下Metrics API的概念
Metrics API相比于之前的监控采集方式(hepaster)是一种新的思路，官方希望核心指标的监控应该是稳定的，版本可控的，且可以直接被用户访问(例如通过使用 kubectl top 命令)，或由集群中的控制器使用(如HPA)，和其他的Kubernetes APIs一样。
官方废弃heapster项目，就是为了将核心资源监控作为一等公民对待，即像pod、service那样直接通过api-server或者client直接访问，不再是安装一个hepater来汇聚且由heapster单独管理。
官方GitHub
https://github.com/kubernetes-sigs/metrics-server
创建Metrics-Server
使用Metrics-Server v0.3.6
unzip metrics-server-0.3.6.zip
修改yaml
[root@master01 ~]# cd metrics-server-0.3.6/deploy/1.8+/
[root@master01 1.8+]# ll
total 28
-rw-r--r-- 1 root root 393 Oct 14 20:42 aggregated-metrics-reader.yaml
-rw-r--r-- 1 root root 308 Oct 14 20:42 auth-delegator.yaml
-rw-r--r-- 1 root root 329 Oct 14 20:42 auth-reader.yaml
-rw-r--r-- 1 root root 298 Oct 14 20:42 metrics-apiservice.yaml
-rw-r--r-- 1 root root 804 Oct 14 20:42 metrics-server-deployment.yaml
-rw-r--r-- 1 root root 291 Oct 14 20:42 metrics-server-service.yaml
-rw-r--r-- 1 root root 517 Oct 14 20:42 resource-reader.yaml
vim metrics-server-deployment.yaml
...
...
...
image: k8s.gcr.io/metrics-server-amd64:v0.3.6
imagePullPolicy: IfNotPresent
args:
- --kubelet-preferred-address-types=InternalIP,Hostname,InternalDNS,ExternalDNS,ExternalIP
- --kubelet-insecure-tls
镜像下载
链接: https://pan.baidu.com/s/1wnKCpBcY2YNKKTPwSnVW0g 提取码: agnv
docker pull registry.aliyuncs.com/k8sxio/metrics-server-amd64:v0.3.6
docker tag registry.aliyuncs.com/k8sxio/metrics-server-amd64:v0.3.6 k8s.gcr.io/metrics-server-amd64:v0.3.6
加载yaml
[root@master01 1.8+]# pwd
/root/metrics-server-0.3.6/deploy/1.8+
[root@master01 1.8+]# kubectl apply -f .
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.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
[root@master01 1.8+]# kubectl get pods -n kube-system | grep metrics
metrics-server-54fff4c8bb-6j5pk 1/1 Running 0 102s
[root@master01 1.8+]# kubectl get apiservices.apiregistration.k8s.io
NAME SERVICE AVAILABLE AGE
v1. Local True 8d
v1.admissionregistration.k8s.io Local True 8d
v1.apiextensions.k8s.io Local True 8d
v1.apps Local True 8d
v1.authentication.k8s.io Local True 8d
v1.authorization.k8s.io Local True 8d
v1.autoscaling Local True 8d
v1.batch Local True 8d
v1.coordination.k8s.io Local True 8d
v1.crd.projectcalico.org Local True 43m
v1.networking.k8s.io Local True 8d
v1.rbac.authorization.k8s.io Local True 8d
v1.scheduling.k8s.io Local True 8d
v1.storage.k8s.io Local True 8d
v1alpha1.settings.k8s.io Local True 8d
v1beta1.admissionregistration.k8s.io Local True 8d
v1beta1.apiextensions.k8s.io Local True 8d
v1beta1.authentication.k8s.io Local True 8d
v1beta1.authorization.k8s.io Local True 8d
v1beta1.batch Local True 8d
v1beta1.certificates.k8s.io Local True 8d
v1beta1.coordination.k8s.io Local True 8d
v1beta1.events.k8s.io Local True 8d
v1beta1.extensions Local True 8d
v1beta1.metrics.k8s.io kube-system/metrics-server True 14m
v1beta1.networking.k8s.io Local True 8d
v1beta1.node.k8s.io Local True 8d
v1beta1.policy Local True 8d
v1beta1.rbac.authorization.k8s.io Local True 8d
v1beta1.scheduling.k8s.io Local True 8d
v1beta1.storage.k8s.io Local True 8d
v2beta1.autoscaling Local True 8d
v2beta2.autoscaling Local True 8d
查看资源
[root@master01 1.8+]# kubectl top nodes
NAME CPU(cores) CPU% MEMORY(bytes) MEMORY%
master01 255m 12% 874Mi 23%
master02 217m 10% 877Mi 23%
master03 187m 9% 815Mi 22%
node01 148m 7% 489Mi 13%
node02 116m 5% 468Mi 12%
node03 115m 5% 457Mi 12%
[root@master01 1.8+]# kubectl top pod --all-namespaces
NAMESPACE NAME CPU(cores) MEMORY(bytes)
kube-system calico-kube-controllers-648f4868b8-pzg2d 2m 13Mi
kube-system calico-node-d4hqw 24m 48Mi
kube-system calico-node-glmcl 24m 48Mi
kube-system calico-node-qm8zz 27m 48Mi
kube-system calico-node-s64r9 25m 48Mi
kube-system calico-node-shxhv 25m 48Mi
kube-system calico-node-zx7nw 25m 48Mi
kube-system coredns-7b8f8b6cf6-gqp8s 3m 10Mi
kube-system coredns-7b8f8b6cf6-mkxdv 3m 10Mi
kube-system etcd-master01 42m 102Mi
kube-system etcd-master02 30m 80Mi
kube-system etcd-master03 33m 87Mi
kube-system kube-apiserver-master01 25m 249Mi
kube-system kube-apiserver-master02 43m 336Mi
kube-system kube-apiserver-master03 28m 267Mi
kube-system kube-controller-manager-master01 12m 40Mi
kube-system kube-controller-manager-master02 1m 14Mi
kube-system kube-controller-manager-master03 1m 12Mi
kube-system kube-proxy-2zbx4 6m 15Mi
kube-system kube-proxy-bbvqk 5m 14Mi
kube-system kube-proxy-j8899 6m 15Mi
kube-system kube-proxy-khrw5 7m 17Mi
kube-system kube-proxy-srpz9 7m 15Mi
kube-system kube-proxy-tz24q 4m 15Mi
kube-system kube-scheduler-master01 2m 13Mi
kube-system kube-scheduler-master02 1m 13Mi
kube-system kube-scheduler-master03 2m 15Mi
kube-system metrics-server-54fff4c8bb-6j5pk 1m 12Mi
HPA
通过kubectl api-versions可以看到，目前有3个版本：
- autoscaling/v1 #只支持通过cpu为参考依据，来改变pod副本数
- autoscaling/v2beta1 #支持通过cpu、内存、连接数以及用户自定义的资源指标数据为参考依据。
- autoscaling/v2beta2 #同上，小的变动
部署HPA
SVC、Deployment资源清单
cat > hpa-deploy.yaml << EOF
apiVersion: v1
kind: Service
metadata:
name: svc-hpa
namespace: default
spec:
selector:
app: myapp
type: NodePort
ports:
- name: http
port: 80
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: myapp-hpa
namespace: default
spec:
replicas: 1
selector:
matchLabels:
app: myapp
template:
metadata:
name: myapp-demo
namespace: default
labels:
app: myapp
spec:
containers:
- name: myapp
image: ikubernetes/myapp:v1
imagePullPolicy: IfNotPresent
ports:
- name: http
containerPort: 80
resources:
requests:
cpu: 50m
memory: 50Mi
limits:
cpu: 50m
memory: 50Mi
EOF
kubectl apply -f hpa-deploy.yaml
HPA资源清单
cat > hpa-myapp.yaml << EOF
apiVersion: autoscaling/v2beta1
kind: HorizontalPodAutoscaler
metadata:
name: myapp-hpa-v2
namespace: default
spec:
minReplicas: 1 ##至少1个副本
maxReplicas: 8 ##最多8个副本
scaleTargetRef:
apiVersion: apps/v1
kind: Deployment
name: myapp-hpa
metrics:
- type: Resource
resource:
name: cpu
targetAverageUtilization: 50 ##注意此时是根据使用率，也可以根据使用量：targetAverageValue
- type: Resource
resource:
name: memory
targetAverageUtilization: 50 ##注意此时是根据使用率，也可以根据使用量：targetAverageValue
EOF
kubectl apply -f hpa-myapp.yaml
[root@master01 ~]# kubectl get all
NAME READY STATUS RESTARTS AGE
pod/myapp-hpa-6cf986669d-vhtb5 1/1 Running 0 2m5s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 8d
service/myapp-svc NodePort 10.106.201.169 <none> 80:30080/TCP 17h
service/svc-hpa NodePort 10.108.166.226 <none> 80:32465/TCP 2m6s
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/myapp-hpa 1/1 1 1 2m5s
NAME DESIRED CURRENT READY AGE
replicaset.apps/myapp-hpa-6cf986669d 1 1 1 2m5s
NAME REFERENCE TARGETS MINPODS MAXPODS REPLICAS AGE
horizontalpodautoscaler.autoscaling/myapp-hpa-v2 Deployment/myapp <unknown>/50%, <unknown>/50% 1 8 0 21s
压测
使用工具模拟压力测试
yum install openssl-devel git
git clone https://github.com/wg/wrk.git
cd wrk
make
mv wrk /usr/bin
wrk -t20 -c30 -d120s --latency http://master01:32465/hostname.html
[root@master01 ~]# kubectl get pods -w
NAME READY STATUS RESTARTS AGE
myapp-hpa-6cf986669d-vhtb5 1/1 Running 0 4h52m
myapp-hpa-6cf986669d-txkrv 0/1 Pending 0 0s
myapp-hpa-6cf986669d-txkrv 0/1 Pending 0 0s
myapp-hpa-6cf986669d-txkrv 0/1 ContainerCreating 0 0s
myapp-hpa-6cf986669d-txkrv 0/1 ContainerCreating 0 3s
myapp-hpa-6cf986669d-txkrv 1/1 Running 0 4s
myapp-hpa-6cf986669d-lfq4l 0/1 Pending 0 0s
myapp-hpa-6cf986669d-lfq4l 0/1 Pending 0 0s
myapp-hpa-6cf986669d-rgsww 0/1 Pending 0 0s
myapp-hpa-6cf986669d-rgsww 0/1 Pending 0 0s
myapp-hpa-6cf986669d-rgsww 0/1 ContainerCreating 0 0s
myapp-hpa-6cf986669d-lfq4l 0/1 ContainerCreating 0 0s
myapp-hpa-6cf986669d-lfq4l 0/1 ContainerCreating 0 2s
myapp-hpa-6cf986669d-rgsww 0/1 ContainerCreating 0 3s
myapp-hpa-6cf986669d-lfq4l 1/1 Running 0 3s
myapp-hpa-6cf986669d-rgsww 1/1 Running 0 4s
myapp-hpa-6cf986669d-8tn4x 0/1 Pending 0 0s
myapp-hpa-6cf986669d-8tn4x 0/1 Pending 0 0s
myapp-hpa-6cf986669d-8tn4x 0/1 ContainerCreating 0 0s
myapp-hpa-6cf986669d-8tn4x 0/1 ContainerCreating 0 2s
myapp-hpa-6cf986669d-8tn4x 1/1 Running 0 3s
[root@master01 ~]# kubectl get hpa
NAME REFERENCE TARGETS MINPODS MAXPODS REPLICAS AGE
myapp-hpa-v2 Deployment/myapp-hpa 2%/50%, 93%/50% 1 8 8 6m41s
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