How to upgrade the nodes manually in the AWS EKS cluster?

Below are steps to upgrade the nodes in the AWS ESK CLuster:

1. Check the available updates

1. FInd the latest AMI ID’s: AWS publishes optimized AMIs for EKS regularly. You can find the latest AMI IDs on the Amazon EKS optimized AMI page.
2. Note the AMI ID that matches your Kubernetes version.

2. Update the Launch Template or Launch Configuration:

1. Update Launch Template (for Managed Node Groups):
   • Go to the EC2 console
   • Navigate to “Launch Templates” and find the one used by your EKS node group.
   • Create a new version of the launch template with the updated AMI ID.
2. Update Launch Configuration (for Self-Managed Node Groups):
   • Go to the EC2 console.
   • Navigate to “Launch Configurations” and create a new launch configuration with the updated AMI ID.

3. Update Managed Node Group:

1.For managed node groups, update the node group to use the new launch template version.

aws eks update-nodegroup-version --cluster-name <cluster-name> --nodegroup-name <nodegroup-name> --launch-template name=<launch-template-name>,version=<version>

4. Drain and Terminate Old Nodes:

1. Drain Nodes:

• Use kubectl to drain the nodes. This will safely evict pods from the nodes.

kubectl drain <node-name> --ignore-daemonsets --delete-emptydir-data

2. Terminate Nodes:

1. Terminate the old nodes from the EC2 console or using AWS CLI.
2. If using managed node groups, you can update the desired capacity to remove old nodes.

5. Verify and Clean Up

1. Verify New Nodes:
   • Ensure new nodes are joining the cluster and that pods are being scheduled correctly.
   • Use kubectl get nodes to check node status.
   • Use kubectl get pods -o wide to ensure pods are running on new nodes.
2. Clean Up:
   • Delete old launch configurations or unused resources if no longer needed.
   • Ensure autoscaling policies are set correctly for the new nodes.