Metrics server is used for gathering kubernetes nodes and pods cpu and ram utilization. In this tutorial ,we will install metrics server on Kubernetes 1.23.
Install metrics server on Kubernetes 1.23
Prerequisites
Working Kubernetes setup
[ved@arch ~]$ kubectl get nodes
NAME STATUS ROLES AGE VERSION
master1.example.com Ready control-plane,master 5d1h v1.23.4
master2.example.com Ready control-plane,master 5d1h v1.23.4
master3.example.com Ready control-plane,master 5d1h v1.23.4
node1.example.com Ready <none> 5d1h v1.23.4
node2.example.com Ready <none> 5d1h v1.23.4
node3.example.com Ready <none> 5d1h v1.23.4
node4.example.com Ready <none> 5d1h v1.23.4Lets create a yaml file containing the metrics server configuration and then deploy the metrics server. Please refer metrics server for releases.
[ved@arch ~]$ vim metrics-server-components.yamlapiVersion: v1
kind: ServiceAccount
metadata:
labels:
k8s-app: metrics-server
name: metrics-server
namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
labels:
k8s-app: metrics-server
rbac.authorization.k8s.io/aggregate-to-admin: "true"
rbac.authorization.k8s.io/aggregate-to-edit: "true"
rbac.authorization.k8s.io/aggregate-to-view: "true"
name: system:aggregated-metrics-reader
rules:
- apiGroups:
- metrics.k8s.io
resources:
- pods
- nodes
verbs:
- get
- list
- watch
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
labels:
k8s-app: metrics-server
name: system:metrics-server
rules:
- apiGroups:
- ""
resources:
- nodes/metrics
verbs:
- get
- apiGroups:
- ""
resources:
- pods
- nodes
verbs:
- get
- list
- watch
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
labels:
k8s-app: metrics-server
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:
labels:
k8s-app: metrics-server
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: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
labels:
k8s-app: metrics-server
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: v1
kind: Service
metadata:
labels:
k8s-app: metrics-server
name: metrics-server
namespace: kube-system
spec:
ports:
- name: https
port: 443
protocol: TCP
targetPort: https
selector:
k8s-app: metrics-server
---
apiVersion: apps/v1
kind: Deployment
metadata:
labels:
k8s-app: metrics-server
name: metrics-server
namespace: kube-system
spec:
selector:
matchLabels:
k8s-app: metrics-server
strategy:
rollingUpdate:
maxUnavailable: 0
template:
metadata:
labels:
k8s-app: metrics-server
spec:
containers:
- args:
- --cert-dir=/tmp
- --secure-port=4443
- --kubelet-preferred-address-types=InternalIP,ExternalIP,Hostname
- --kubelet-use-node-status-port
- --kubelet-insecure-tls
- --metric-resolution=15s
image: k8s.gcr.io/metrics-server/metrics-server:v0.6.1
imagePullPolicy: IfNotPresent
livenessProbe:
failureThreshold: 3
httpGet:
path: /livez
port: https
scheme: HTTPS
periodSeconds: 10
name: metrics-server
ports:
- containerPort: 4443
name: https
protocol: TCP
readinessProbe:
failureThreshold: 3
httpGet:
path: /readyz
port: https
scheme: HTTPS
initialDelaySeconds: 20
periodSeconds: 10
resources:
requests:
cpu: 100m
memory: 200Mi
securityContext:
allowPrivilegeEscalation: false
readOnlyRootFilesystem: true
runAsNonRoot: true
runAsUser: 1000
volumeMounts:
- mountPath: /tmp
name: tmp-dir
nodeSelector:
kubernetes.io/os: linux
priorityClassName: system-cluster-critical
serviceAccountName: metrics-server
volumes:
- emptyDir: {}
name: tmp-dir
---
apiVersion: apiregistration.k8s.io/v1
kind: APIService
metadata:
labels:
k8s-app: metrics-server
name: v1beta1.metrics.k8s.io
spec:
group: metrics.k8s.io
groupPriorityMinimum: 100
insecureSkipTLSVerify: true
service:
name: metrics-server
namespace: kube-system
version: v1beta1
versionPriority: 100
[ved@arch ~]$ kubectl apply -f metrics-server-components.yaml
serviceaccount/metrics-server created
clusterrole.rbac.authorization.k8s.io/system:aggregated-metrics-reader created
clusterrole.rbac.authorization.k8s.io/system:metrics-server created
rolebinding.rbac.authorization.k8s.io/metrics-server-auth-reader created
clusterrolebinding.rbac.authorization.k8s.io/metrics-server:system:auth-delegator created
clusterrolebinding.rbac.authorization.k8s.io/system:metrics-server created
service/metrics-server created
deployment.apps/metrics-server created
apiservice.apiregistration.k8s.io/v1beta1.metrics.k8s.io createdCheck pods in the kube-system namespace for newly deployed metrics-server
[ved@arch ~]$ kubectl get pods -n kube-system -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
coredns-64897985d-67p2p 1/1 Running 2 (141m ago) 22h 10.38.0.1 node1.example.com <none> <none>
coredns-64897985d-zkcn7 1/1 Running 0 30h 10.47.0.3 node3.example.com <none> <none>
kube-apiserver-master1.example.com 1/1 Running 13 (163m ago) 22h 192.168.122.113 master1.example.com <none> <none>
kube-apiserver-master2.example.com 1/1 Running 4 (163m ago) 23h 192.168.122.114 master2.example.com <none> <none>
kube-apiserver-master3.example.com 1/1 Running 4 (163m ago) 22h 192.168.122.115 master3.example.com <none> <none>
kube-controller-manager-master1.example.com 1/1 Running 24 (163m ago) 5d1h 192.168.122.113 master1.example.com <none> <none>
kube-controller-manager-master2.example.com 1/1 Running 20 (163m ago) 5d1h 192.168.122.114 master2.example.com <none> <none>
kube-controller-manager-master3.example.com 1/1 Running 23 (163m ago) 5d1h 192.168.122.115 master3.example.com <none> <none>
kube-proxy-2b84t 1/1 Running 13 (163m ago) 5d1h 192.168.122.114 master2.example.com <none> <none>
kube-proxy-4nxdj 1/1 Running 12 (163m ago) 5d1h 192.168.122.113 master1.example.com <none> <none>
kube-proxy-6st5h 1/1 Running 19 (38m ago) 5d1h 192.168.122.111 node2.example.com <none> <none>
kube-proxy-82vnl 1/1 Running 14 (141m ago) 5d1h 192.168.122.110 node1.example.com <none> <none>
kube-proxy-bzsqm 1/1 Running 22 (163m ago) 5d1h 192.168.122.115 master3.example.com <none> <none>
kube-proxy-s7ttn 1/1 Running 5 (145m ago) 5d1h 192.168.122.116 node4.example.com <none> <none>
kube-proxy-z2k46 1/1 Running 0 5d1h 192.168.122.112 node3.example.com <none> <none>
kube-scheduler-master1.example.com 1/1 Running 23 (163m ago) 5d1h 192.168.122.113 master1.example.com <none> <none>
kube-scheduler-master2.example.com 1/1 Running 15 (163m ago) 5d1h 192.168.122.114 master2.example.com <none> <none>
kube-scheduler-master3.example.com 1/1 Running 25 (163m ago) 5d1h 192.168.122.115 master3.example.com <none> <none>
metrics-server-574849569f-ng7xs 1/1 Running 0 35m 10.34.0.3 node2.example.com <none> <none>
weave-net-bmfvp 2/2 Running 0 21h 192.168.122.112 node3.example.com <none> <none>
weave-net-c9pbn 2/2 Running 11 (145m ago) 21h 192.168.122.116 node4.example.com <none> <none>
weave-net-hfh5l 2/2 Running 4 (163m ago) 21h 192.168.122.114 master2.example.com <none> <none>
weave-net-rmmdf 2/2 Running 4 (163m ago) 21h 192.168.122.113 master1.example.com <none> <none>
weave-net-sc8vc 2/2 Running 4 (163m ago) 21h 192.168.122.115 master3.example.com <none> <none>
weave-net-srpnf 2/2 Running 19 (38m ago) 21h 192.168.122.111 node2.example.com <none> <none>
weave-net-xgx2b 2/2 Running 11 (141m ago) 21h 192.168.122.110 node1.example.com Lets check nodes utilization using below kubectl command
[ved@arch ~]$ kubectl top nodes
NAME CPU(cores) CPU% MEMORY(bytes) MEMORY%
master1.example.com 131m 6% 777Mi 44%
master2.example.com 149m 7% 732Mi 42%
master3.example.com 116m 5% 735Mi 42%
node1.example.com 76m 3% 588Mi 33%
node2.example.com 43m 2% 649Mi 37%
node3.example.com 65m 3% 469Mi 27%
node4.example.com 27m 1% 398Mi 22% Lets check pods utilization using Kubernetes metrics server top command for the kube-system namespace
[ved@arch ~]$ kubectl top pods -n kube-system
NAME CPU(cores) MEMORY(bytes)
coredns-64897985d-67p2p 2m 16Mi
coredns-64897985d-zkcn7 2m 16Mi
kube-apiserver-master1.example.com 61m 304Mi
kube-apiserver-master2.example.com 51m 280Mi
kube-apiserver-master3.example.com 49m 288Mi
kube-controller-manager-master1.example.com 18m 50Mi
kube-controller-manager-master2.example.com 2m 20Mi
kube-controller-manager-master3.example.com 2m 25Mi
kube-proxy-2b84t 1m 15Mi
kube-proxy-4nxdj 1m 15Mi
kube-proxy-6st5h 1m 13Mi
kube-proxy-82vnl 1m 15Mi
kube-proxy-bzsqm 1m 16Mi
kube-proxy-s7ttn 1m 16Mi
kube-proxy-z2k46 1m 15Mi
kube-scheduler-master1.example.com 3m 21Mi
kube-scheduler-master2.example.com 3m 19Mi
kube-scheduler-master3.example.com 4m 22Mi
metrics-server-574849569f-ng7xs 4m 24Mi
weave-net-bmfvp 15m 90Mi
weave-net-c9pbn 2m 80Mi
weave-net-hfh5l 2m 74Mi
weave-net-rmmdf 2m 72Mi
weave-net-sc8vc 2m 71Mi
weave-net-srpnf 2m 81Mi
weave-net-xgx2b 2m 80Mi Conclusion
We have successfully Install metrics server on Kubernetes and verified nodes and pods utilization using Kubernetes metrics server.
