How to configure autoscaling for existing AWS EKS Cluster
The Cluster Autoscaler is essential for automatically adjusting the number of nodes in your cluster based on resource requirements and constraints.
Instructions
step-by-step guide:
Deploy Cluster Autoscaler
If the Cluster Autoscaler is not deployed, you'll need to deploy it to allow for dynamic node scaling based on resource requirements. Here's a simplified process to do so:
Get your EKS Cluster Name:
eksctl get clusterConfigure IAM OIDC Provider for EKS:
eksctl utils associate-iam-oidc-provider --region=<your-region> --name=<your-cluster-name> --approveCreate IAM Policy for Cluster Autoscaler: Name this policy as ca-iam-policy.json
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": [
"autoscaling:DescribeAutoScalingGroups",
"autoscaling:DescribeAutoScalingInstances",
"autoscaling:DescribeLaunchConfigurations",
"autoscaling:DescribeTags",
"autoscaling:SetDesiredCapacity",
"autoscaling:TerminateInstanceInAutoScalingGroup",
"ec2:DescribeLaunchTemplateVersions"
],
"Resource": "*"
}
]
}
Create the policy using the following command:
Attach the Policy to Your Node IAM Role:
Replace <NodeInstanceRole> with your node's IAM role:
The NodeInstanceRole is the IAM role that's attached to your EKS worker nodes. Here's how you can retrieve it:
Look for the RoleARN in the output, and the role name is the final part of the ARN after the last /.
For example:
eksctl get iamidentitymapping --region ap-south-1 --name unified-dev
Flag --name has been deprecated, use --cluster
Here unified-dev20230314050701738200000018 is the NodeInstanceRole
ARN USERNAME GROUPS ACCOUNT
arn:aws:iam::349271159511:role/unified-dev20230314050701738200000018 system:node:{{EC2PrivateDNSName}} system:bootstrappers,system:nodes
Deploy Cluster Autoscaler:
Edit the Cluster Autoscaler Deployment:
Find the line with the command field and modify the --node-group-auto-discovery flag to reflect your EKS cluster name:
Ensure that Cluster Autoscaler is Configured to Discover ASGs:
Cluster Autoscaler should be configured to automatically discover ASGs tagged with specific tags. Ensure your ASGs have the correct tags:
k8s.io/cluster-autoscaler/enabled
k8s.io/cluster-autoscaler/<YOUR CLUSTER NAME>
Make sure the CA deployment contains:
--cloud-provider=aws
--node-group-auto-discovery=asg:tag=k8s.io/cluster-autoscaler/enabled,k8s.io/cluster-autoscaler/<YOUR CLUSTER>
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