Install Metrics Server in Kubernetes
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Installing Metrics Server in Kubernetes
The Metrics Server is a scalable, efficient source of container resource metrics for Kubernetes built-in autoscaling pipelines. This guide will help you install the Metrics Server using a pre-configured YAML file.
Prerequisites
- A running Kubernetes cluster
- kubectl command-line tool configured to communicate with your cluster
Installation Steps
1. Create a file named metrics-server.yaml and paste the following content:
apiVersion: 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:
hostNetwork: true
containers:
- args:
#https://github.com/kubernetes-sigs/metrics-server/blob/e4416ed3701d994ee2619d83821cc3a02f70e0c2/docs/command-line-flags.txt#L22
- --cert-dir=/tmp
- --secure-port=4443
- --kubelet-preferred-address-types=InternalIP,ExternalIP,Hostname
- --metric-resolution=15s
- --kubelet-insecure-tls=true
- --kubelet-use-node-status-port
image: registry.k8s.io/metrics-server/metrics-server:v0.7.0
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
# set the node's role to control-plane to run metrics-server on master node
node-role.kubernetes.io/control-plane: ""
tolerations:
- key: node-role.kubernetes.io/control-plane
operator: Exists
effect: NoSchedule
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
2. Apply the configuration using kubectl:
kubectl apply -f metrics-server.yaml
3. Verify the installation by checking the status of the metrics-server pod:
kubectl get pods -n kube-system | grep metrics-server
You should see the metrics-server pod running.
Configuration Notes
- The Metrics Server is configured to run on the control plane node due to the
nodeSelectorandtolerationssettings. - Insecure TLS is enabled with
--kubelet-insecure-tls=truefor ease of setup. In production environments, consider configuring proper TLS certificates. - The Metrics Server uses host networking (
hostNetwork: true) for improved performance.
Troubleshooting
If you encounter issues:
1. Check the logs of the metrics-server pod:
kubectl logs -n kube-system $(kubectl get pods -n kube-system | grep metrics-server | awk '{print $1}')
2. Ensure your cluster nodes have the required labels, especially for the control plane node:
kubectl get nodes --show-labels
3. Verify that the APIService is available:
kubectl get apiservice v1beta1.metrics.k8s.io -o yaml