How to enable Cluster Autoscaler for a cluster setup with kops

Question

Im trying to setup a cluster autoscaler. after following docs and trying from this thread to do one , i wasn't able to create one.

Created a Cluster using kops cli

 kops create cluster --name=pavan.k8s.local --zones=us-east-1a --cloud=aws --master-size=t2.medium --node-size=t2.medium

Replaced the created node with a new node of these configurations

apiVersion: kops.k8s.io/v1alpha2
kind: InstanceGroup
metadata:
  labels:
    kops.k8s.io/cluster: pavan.k8s.local
  name: nodes-us-east-1a
spec:
  image: 099720109477/ubuntu/images/hvm-ssd/ubuntu-focal-20.04-amd64-server-20221206
  instanceMetadata:
    httpPutResponseHopLimit: 1
    httpTokens: required
  machineType: t3.medium
  rootVolumeSize: 8
  rootVolumeType: gp2
  maxPrice: '0.20'
  maxSize: 4
  minSize: 1
  role: Node
  subnets:
    - us-east-1a

Edited the node group

$ kops edit ig nodes

spec:
  cloudLabels:
    app.kubernetes.io/cluster/pavan.k8s.local: owned
    k8s.io/cluster-autoscaler/enabled: ""
    k8s.io/cluster-autoscaler/node-template/label: ""

kubernetes.io/cluster/<CLUSTER_NAME>: owned gave an error initially saying "kubernetes.io/cluster" prefix is reserved for use by Kubernetes . so i added app.kubernetes.io/cluster/pavan.k8s.local: owned instead

I later edited the cluster

$ kops edit cluster

spec:
  additionalPolicies:
    node: |
      [
        {
          "Effect": "Allow",
          "Action": [
            "autoscaling:DescribeAutoScalingGroups",
            "autoscaling:DescribeAutoScalingInstances",
            "autoscaling:SetDesiredCapacity",
            "autoscaling:DescribeLaunchConfigurations",
            "autoscaling:DescribeTags",
            "autoscaling:TerminateInstanceInAutoScalingGroup"
          ],
          "Resource": ["*"]
        }
      ]

Deployed an nginx app

apiVersion: apps/v1
kind: Deployment
metadata:
  name: test-app
  labels:
    app: test-app
spec:
  replicas: 1
  selector:
    matchLabels:
      app: test-app
  template:
    metadata:
      labels:
        app: test-app
    spec:
      containers:
        - name: test-app
          image: nginx:1.14.2
          ports:
            - containerPort: 80
          resources:
            requests:
              cpu: 200m
              memory: 1Gi
            limits:
              cpu: 2000m
              memory: 4Gi

Scaled the deployment

$ kubectl scale deploy test-app --replicas=4

$ kubectl get pods
NAME                       READY   STATUS    RESTARTS   AGE
test-app-cf78774cf-7f59b   0/1     Pending   0          5m
test-app-cf78774cf-ctrpx   1/1     Running   0          6m
test-app-cf78774cf-jf76d   1/1     Running   0          6m
test-app-cf78774cf-p8gwn   1/1     Running   0          5m

Message:

0/2 nodes are available: 1 Insufficient memory, 1 node(s) had untolerated taint {node-role.kubernetes.io/control-plane: }. preemption: 0/2 nodes are available: 1 No preemption victims found for incoming pod, 1 Preemption is not helpful for scheduling.

Can someone Please enlighten me on how to do this in detail?

Thank you.