Kubernetes Metrics-Server

github地址：https://github.com/kubernetes-incubator/metrics-server

官网介绍：https://kubernetes.io/docs/tasks/debug-application-cluster/core-metrics-pipeline/

Starting from Kubernetes 1.8, resource usage metrics, such as container CPU and memory usage, are available in Kubernetes through the Metrics API. These metrics can be either accessed directly by user, for example by using 

kubectl top

 command, or used by a controller in the cluster, e.g. Horizontal Pod Autoscaler, to make decisions.

metrics-server.yaml

---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: metrics-server
  namespace: kube-system

---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: system:metrics-server
rules:
- apiGroups:
  - ""
  resources:
  - pods
  - nodes
  - nodes/stats
  - namespaces
  verbs:
  - get
  - list
  - watch
- apiGroups:
  - "extensions"
  resources:
  - deployments
  verbs:
  - get
  - list
  - watch

---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: system:metrics-server
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: system:metrics-server
subjects:
- kind: ServiceAccount
  name: metrics-server
  namespace: kube-system

---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: metrics-server-auth-reader
  namespace: kube-system
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: extension-apiserver-authentication-reader
subjects:
- kind: ServiceAccount
  name: metrics-server
  namespace: kube-system

---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: metrics-server:system:auth-delegator
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: system:auth-delegator
subjects:
- kind: ServiceAccount
  name: metrics-server
  namespace: kube-system

---
apiVersion: apiregistration.k8s.io/v1beta1
kind: APIService
metadata:
  name: v1beta1.metrics.k8s.io
spec:
  service:
    name: metrics-server
    namespace: kube-system
  group: metrics.k8s.io
  version: v1beta1
  insecureSkipTLSVerify: true
  groupPriorityMinimum: 100
  versionPriority: 100

---
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:
      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:v0.3.0
        command:
        - /metrics-server
        - --kubelet-insecure-tls
        - --kubelet-preferred-address-types=InternalIP
        volumeMounts:
        - name: tmp-dir
          mountPath: /tmp

---
apiVersion: v1
kind: Service
metadata:
  name: metrics-server
  namespace: kube-system
  labels:
    kubernetes.io/name: "Metrics-server"
spec:
  selector:
    k8s-app: metrics-server
  ports:
  - port: 443
    protocol: TCP
    targetPort: 443      

yaml

[root@node01 metrics-server]# kubectl get hpa
NAME         REFERENCE           TARGETS   MINPODS   MAXPODS   REPLICAS   AGE
tomcat-hpa   Deployment/tomcat   0%/5%     1         5         1          1h

[root@node01 metrics-server]# kubectl top node
NAME      CPU(cores)   CPU%      MEMORY(bytes)   MEMORY%   
node01    653m         16%       3045Mi          39%       

[root@node01 metrics-server]# kubectl top pod
NAME                      CPU(cores)   MEMORY(bytes)   
lxcfs-8tg6b               1m           2Mi             
mysql-85c85c5668-fr6j7    1m           462Mi           
tomcat-78c9778858-424gc   2m           113Mi    
       
[root@node01 metrics-server]# kubectl top pod
NAME                      CPU(cores)   MEMORY(bytes)   
lxcfs-8tg6b               1m           2Mi             
mysql-85c85c5668-fr6j7    1m           462Mi           
tomcat-78c9778858-424gc   2m           113Mi           

[root@node01 metrics-server]# kubectl top pod --namespace=kube-system 
NAME                                   CPU(cores)   MEMORY(bytes)   
coredns-777d78ff6f-rrpx8               2m           9Mi             
coredns-777d78ff6f-tql47               2m           9Mi             
etcd-node01                            16m          96Mi            
kube-apiserver-node01                  34m          485Mi           
kube-controller-manager-node01         49m          73Mi            
kube-flannel-ds-rxrp5                  3m           14Mi            
kube-proxy-r6bd2                       2m           20Mi            
kube-scheduler-node01                  10m          15Mi            
kubernetes-dashboard-d4866d978-kpz4m   1m           19Mi            
metrics-server-84bd4db594-fz2k2        1m           16Mi