Metrics Server AddOn

Metrics Server is a scalable, efficient source of container resource metrics for Kubernetes built-in autoscaling pipelines. It is not deployed by default in Amazon EKS clusters. The Metrics Server is commonly used by other Kubernetes add ons, such as the Horizontal Pod Autoscaler, Vertical Autoscaling or the Kubernetes Dashboard.

Important: Don't use Metrics Server when you need an accurate source of resource usage metrics or as a monitoring solution.

Usage

index.ts

import 'source-map-support/register';
import * as cdk from 'aws-cdk-lib';
import * as blueprints from '@aws-quickstart/eks-blueprints';

const app = new cdk.App();

const addOn = new blueprints.addons.MetricsServerAddOn('v0.5.0');

const blueprint = blueprints.EksBlueprint.builder()
  .version("auto")
  .addOns(addOn)
  .build(app, 'my-stack-name');

Once deployed, you can see metrics-server pod in the kube-system namespace.

$ kubectl get deployments -n kube-system

NAME                                                          READY   UP-TO-DATE   AVAILABLE   AGE
blueprints-addon-metrics-server                               1/1     1            1           20m

Functionality

1. Deploys the metrics-server helm chart in kube-system namespace by default.
2. Supports standard helm configuration options.
3. Supports createNamespace configuration to deploy the addon to a customized namespace.

Testing with Kubernetes Dashboard

For testing, we will use the Kubernetes Dashboard to view CPU and memory metrics of our cluster.

Apply the kubernetes dashboard manifest.

$ kubectl apply -f https://raw.githubusercontent.com/kubernetes/dashboard/v2.0.5/aio/deploy/recommended.yaml

namespace/kubernetes-dashboard created
serviceaccount/kubernetes-dashboard created
service/kubernetes-dashboard created
secret/kubernetes-dashboard-certs created
secret/kubernetes-dashboard-csrf created
secret/kubernetes-dashboard-key-holder created
configmap/kubernetes-dashboard-settings created
role.rbac.authorization.k8s.io/kubernetes-dashboard created
clusterrole.rbac.authorization.k8s.io/kubernetes-dashboard created
rolebinding.rbac.authorization.k8s.io/kubernetes-dashboard created
clusterrolebinding.rbac.authorization.k8s.io/kubernetes-dashboard created
deployment.apps/kubernetes-dashboard created
service/dashboard-metrics-scraper created
deployment.apps/dashboard-metrics-scraper created

Create a file called eks-admin-service-account.yaml with the text below. This manifest defines a service account and cluster role binding called eks-admin.

$ cat << 'EOF' >> eks-admin-service-account.yaml
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: eks-admin
  namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
  name: eks-admin
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: cluster-admin
subjects:
- kind: ServiceAccount
  name: eks-admin
  namespace: kube-system
EOF

Apply the service account and cluster role binding to your cluster.

$ kubectl apply -f eks-admin-service-account.yaml

serviceaccount/eks-admin created
clusterrolebinding.rbac.authorization.k8s.io/eks-admin created

Retrieve an authentication token for the eks-admin service account. Copy the value from the output. You use this token to connect to the dashboard.

$ kubectl -n kube-system describe secret $(kubectl -n kube-system get secret | grep eks-admin | awk '{print $1}')

Name:         eks-admin-token-dwzb2
Namespace:    kube-system
Labels:       <none>
Annotations:  kubernetes.io/service-account.name: eks-admin
              kubernetes.io/service-account.uid: 6fb4eb46-553e-44bf-b0e7-9ae8f5f500d6

Type:  kubernetes.io/service-account-token

Data
====
ca.crt:     1066 bytes
namespace:  11 bytes
token:      XXXXXXXXXXXXXXXXXXXXXX

Start the kubectl proxy.

$ kubectl proxy

Open the dashboard in your browser and login using the value for token above.

Note: It may take a few minutes before CPU and memory metrics appear in the dashboard