Cluster Autoscaler configure on AWS EKS -1.24

Ashish Gajjar - Nov 1 - - Dev Community

Introduction :
The Kubernetes Cluster Autoscaler automatically adjusts the number of nodes in your cluster when pods fail or are rescheduled onto other nodes. The Cluster Autoscaler uses Auto Scaling groups. For more information, see Cluster Autoscaler on AWS.

Image description
Step 1: Create a EKS Cluster

  • performed Step 1 : to step 5 : Click here

Step 2: Verify how many nodes and pods are running
Node :

[root@ip-172-31-18-194 ~]# kubectl get nodes
NAME                            STATUS     ROLES    AGE     VERSION
ip-192-168-5-245.ec2.internal   Ready      <none>   4m19s   v1.24.17-eks-e71965b
ip-192-168-63-39.ec2.internal   Ready      <none>   2s      v1.24.17-eks-e71965b
Enter fullscreen mode Exit fullscreen mode

Pods:

[root@ip-172-31-18-194 ~]# kubectl get po -A
NAMESPACE     NAME                       READY   STATUS    RESTARTS   AGE
kube-system   aws-node-4fdfg             1/1     Running   0          2m50s
kube-system   aws-node-mm84r             1/1     Running   0          2m53s
kube-system   coredns-79989457d9-798tx   1/1     Running   0          10m
kube-system   coredns-79989457d9-7fhzl   1/1     Running   0          10m
kube-system   kube-proxy-rkbzz           1/1     Running   0          2m50s
kube-system   kube-proxy-vfq7k           1/1     Running   0          2m53s
Enter fullscreen mode Exit fullscreen mode

Step 3: Create a IAM OIDC Provider
IAM OIDC is used for authorizing the Cluster Autoscaler to launch or terminate instances under an Auto Scaling group.
Open EKS Dashboard and copy a OpenID Connect Provider link
Image description

  • Open a IAM Providers Image description
  • Click “Add provider,” select “OpenID Connect,” and click “Get thumbprint” as shown below: Image description
  • Then enter the “Audience” (sts.amazonaws.com in our example pointing to the AWS STS, also known as the Security Token Service) and click the add provider Image description
  • Adding identity information on identity providers Image description Step 4: Create IAM Policy Create a Policy with necessary permission. Image description
  • To create the policy with the necessary permissions, save the below file as AmazonEKSClusterAutoscalerPolicy 
{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "autoscaling:DescribeAutoScalingGroups",
                "autoscaling:DescribeAutoScalingInstances",
                "autoscaling:DescribeLaunchConfigurations",
                "autoscaling:DescribeScalingActivities",
                "autoscaling:DescribeTags",
                "ec2:DescribeInstanceTypes",
                "ec2:DescribeLaunchTemplateVersions"
            ],
            "Resource": [
                "*"
            ]
        },
        {
            "Effect": "Allow",
            "Action": [
                "autoscaling:SetDesiredCapacity",
                "autoscaling:TerminateInstanceInAutoScalingGroup",
                "ec2:DescribeImages",
                "ec2:GetInstanceTypesFromInstanceRequirements",
                "eks:DescribeNodegroup"
            ],
            "Resource": [
                "*"
            ]
        }
    ]
}
Enter fullscreen mode Exit fullscreen mode
  • Review and create a policy Image description Step 5 : Create a IAM Role for the provider. Create role Image description Select the web identity

  • Select identity provide and audience click next.
    Image description

  • Add Policy AmazonEKSClusterAutoscalerPolicy
    Image description
    Click Next and provide Role Name : EKS_Autoscaler
    Image description

Image description

  • verify the IAM role and make sure the policy is attached. Image description Edit the “Trust relationships.” Before Edit “Trust relationships.” 
{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Principal": {
                "Federated": "arn:aws:iam::256050093938:oidc-provider/oidc.eks.us-east-1.amazonaws.com/id/CD6440D4E14822FC649C070BD8C41A96"
            },
            "Action": "sts:AssumeRoleWithWebIdentity",
            "Condition": {
                "StringEquals": {
                    "oidc.eks.us-east-1.amazonaws.com/id/CD6440D4E14822FC649C070BD8C41A96:aud": "sts.amazonaws.com"
                }
            }
        }
    ]
}
Enter fullscreen mode Exit fullscreen mode
  • After Edit “Trust relationships.” 
{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Principal": {
                "Federated": "arn:aws:iam::256050093938:oidc-provider/oidc.eks.us-east-1.amazonaws.com/id/CD6440D4E14822FC649C070BD8C41A96"
            },
            "Action": "sts:AssumeRoleWithWebIdentity",
            "Condition": {
                "StringEquals": {
                    "oidc.eks.us-east-1.amazonaws.com/id/CD6440D4E14822FC649C070BD8C41A96:aud": "sts.amazonaws.com",
                    "oidc.eks.us-east-1.amazonaws.com/id/CD6440D4E14822FC649C070BD8C41A96:sub": "system:serviceaccount:kube-system:cluster-autoscaler"
                }
            }
        }
    ]
}
Enter fullscreen mode Exit fullscreen mode

Step 6 : Deploy a Cluster Autoscaler
Next, we deploy Cluster Autoscaler. To do so, you must use the Amazon Resource Names (ARN) number of the IAM role created in our earlier step.
The content intended to save into a file (make sure you copy all of the content presented over the next page):
Modify below two lines

  • Line 8 : change IAM Role name
  • Line 159 : --node-group-auto-discovery = This is used by CA to discover the Auto Scaling group based on its tag. 
apiVersion: v1
kind: ServiceAccount
metadata:
  labels:
    k8s-addon: cluster-autoscaler.addons.k8s.io
    k8s-app: cluster-autoscaler
  annotations:
    eks.amazonaws.com/role-arn: arn:aws:iam::256050093938:role/EKS_Autoscaler
  name: cluster-autoscaler
  namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: cluster-autoscaler
  labels:
    k8s-addon: cluster-autoscaler.addons.k8s.io
    k8s-app: cluster-autoscaler
rules:
  - apiGroups: [""]
    resources: ["events", "endpoints"]
    verbs: ["create", "patch"]
  - apiGroups: [""]
    resources: ["pods/eviction"]
    verbs: ["create"]
  - apiGroups: [""]
    resources: ["pods/status"]
    verbs: ["update"]
  - apiGroups: [""]
    resources: ["endpoints"]
    resourceNames: ["cluster-autoscaler"]
    verbs: ["get", "update"]
  - apiGroups: [""]
    resources: ["nodes"]
    verbs: ["watch", "list", "get", "update"]
  - apiGroups: [""]
    resources:
      - "pods"
      - "services"
      - "replicationcontrollers"
      - "persistentvolumeclaims"
      - "persistentvolumes"
    verbs: ["watch", "list", "get"]
  - apiGroups: ["extensions"]
    resources: ["replicasets", "daemonsets"]
    verbs: ["watch", "list", "get"]
  - apiGroups: ["policy"]
    resources: ["poddisruptionbudgets"]
    verbs: ["watch", "list"]
  - apiGroups: ["apps"]
    resources: ["statefulsets", "replicasets", "daemonsets"]
    verbs: ["watch", "list", "get"]
  - apiGroups: ["storage.k8s.io"]
    resources: ["storageclasses", "csinodes"]
    verbs: ["watch", "list", "get"]
  - apiGroups: ["batch", "extensions"]
    resources: ["jobs"]
    verbs: ["get", "list", "watch", "patch"]
  - apiGroups: ["coordination.k8s.io"]
    resources: ["leases"]
    verbs: ["create"]
  - apiGroups: ["coordination.k8s.io"]
    resourceNames: ["cluster-autoscaler"]
    resources: ["leases"]
    verbs: ["get", "update"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: cluster-autoscaler
  namespace: kube-system
  labels:
    k8s-addon: cluster-autoscaler.addons.k8s.io
    k8s-app: cluster-autoscaler
rules:
  - apiGroups: [""]
    resources: ["configmaps"]
    verbs: ["create","list","watch"]
  - apiGroups: [""]
    resources: ["configmaps"]
    resourceNames: ["cluster-autoscaler-status", "cluster-autoscaler-priority-expander"]
    verbs: ["delete", "get", "update", "watch"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: cluster-autoscaler
  labels:
    k8s-addon: cluster-autoscaler.addons.k8s.io
    k8s-app: cluster-autoscaler
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: cluster-autoscaler
subjects:
  - kind: ServiceAccount
    name: cluster-autoscaler
    namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: cluster-autoscaler
  namespace: kube-system
  labels:
    k8s-addon: cluster-autoscaler.addons.k8s.io
    k8s-app: cluster-autoscaler
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: cluster-autoscaler
subjects:
  - kind: ServiceAccount
    name: cluster-autoscaler
    namespace: kube-system
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: cluster-autoscaler
  namespace: kube-system
  labels:
    app: cluster-autoscaler
spec:
  replicas: 1
  selector:
    matchLabels:
      app: cluster-autoscaler
  template:
    metadata:
      labels:
        app: cluster-autoscaler
      annotations:
        cluster-autoscaler.kubernetes.io/safe-to-evict: 'false'
    spec:
      serviceAccountName: cluster-autoscaler
      containers:
        - image: k8s.gcr.io/autoscaling/cluster-autoscaler:v1.20.0
          name: cluster-autoscaler
          resources:
            limits:
              cpu: 100m
              memory: 500Mi
            requests:
              cpu: 100m
              memory: 500Mi
          command:
            - ./cluster-autoscaler
            - --v=4
            - --stderrthreshold=info
            - --cloud-provider=aws
            - --skip-nodes-with-local-storage=false
            - --expander=least-waste
            - --node-group-auto-discovery=asg:tag=k8s.io/cluster-autoscaler/enabled,k8s.io/cluster-autoscaler/ashish
            - --balance-similar-node-groups
            - --skip-nodes-with-system-pods=false
          volumeMounts:
            - name: ssl-certs
              mountPath: /etc/ssl/certs/ca-certificates.crt #/etc/ssl/certs/ca-bundle.crt for Amazon Linux Worker Nodes
              readOnly: true
          imagePullPolicy: "Always"
      volumes:
        - name: ssl-certs
          hostPath:
            path: "/etc/ssl/certs/ca-bundle.crt"
Enter fullscreen mode Exit fullscreen mode

To deploy CA, save the following content presented after the command below in a file and run this provided command:

kubectl apply -f cluster-autoscaler.yaml
serviceaccount/cluster-autoscaler created
clusterrole.rbac.authorization.k8s.io/cluster-autoscaler created
role.rbac.authorization.k8s.io/cluster-autoscaler created
clusterrolebinding.rbac.authorization.k8s.io/cluster-autoscaler created
rolebinding.rbac.authorization.k8s.io/cluster-autoscaler created
deployment.apps/cluster-autoscaler created
Enter fullscreen mode Exit fullscreen mode

The expected results are displayed below.

[root@ip-172-31-18-194 ~]# kubectl get po -A
NAMESPACE     NAME                                  READY   STATUS    RESTARTS   AGE
kube-system   aws-node-2frzk                        1/1     Running   0          67m
kube-system   aws-node-drmtr                        1/1     Running   0          63m
kube-system   cluster-autoscaler-657d67cd5d-l7q4m   1/1     Running   0          8s
kube-system   coredns-79989457d9-89f48              1/1     Running   0          75m
kube-system   coredns-79989457d9-ddvvb              1/1     Running   0          75m
kube-system   kube-proxy-hpzxj                      1/1     Running   0          63m
kube-system   kube-proxy-vb2gj                      1/1     Running   0          67m
Enter fullscreen mode Exit fullscreen mode

The expected results are displayed below.

[root@ip-172-31-18-194 ~]# kubectl get nodes
NAME                            STATUS   ROLES    AGE   VERSION
ip-192-168-5-245.ec2.internal   Ready    <none>   76m   v1.24.17-eks-e71965b
ip-192-168-63-39.ec2.internal   Ready    <none>   72m   v1.24.17-eks-e71965b
Enter fullscreen mode Exit fullscreen mode

Troubleshoot :
verify the logs by issuing this command:

kubectl logs -l app=cluster-autoscaler -n kubesystem -f
Enter fullscreen mode Exit fullscreen mode

Conclusion :
Cluster Autoscaler plays a vital role in a Kubernetes cluster by ensuring adequate computing resources are available by adding the nodes to a cluster and keeping infrastructure costs down by removing nodes

Image
Total Web Design

business, it, webdesign
Image
Why Nobody Cares About Bifold Door Repair
Image
Docker Networking every developer should know

docker, devops, container
Image
13 Things You Should Know About Bi-Fold Door Repair That You Might Not Have Known
Image
Guide to Full Stack Web Development Services for Enterprises

fullstack, webdev, business, startup
Image
7METER LINK LOGIN
Image
Ten Taboos About Couches For Sale You Shouldn't Share On Twitter
Image
Why You're Failing At Bi-Fold Door Repair
Image
Asbestos Claims's History History Of Asbestos Claims
Image
apa yang beri keuntungan dari judi slots online?
Image
situs slots online tenar dengan promosi bonus menarik
Image
Meble, które zmieniają każdą przestrzeń: Inspiracje i trendy na 2023 rok
Image
10 Websites To Help You Develop Your Knowledge About Bi-Fold Door Repair
Image
NESTES IF

beginners, basic, coding
Image
A Single Oven With Grill is a Dream Come True
Image
7METER LINK LOGIN
Image
A Deep Dive into new and this in JavaScript: Unlocking the Power of Object-Oriented Programming

javascript, webdev, programming, learning
Image
A Single Fan Oven With Grill Will Handle All Your Cooking Needs
Image
gohancasino67
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .