How to upgrade the nodes in the AWS EKS cluster using Terraform as a Iaac?

Upgrading nodes in an EKS cluster using Terraform involves updating the configuration of the node group to use a new Amazon Machine Image (AMI). Here’s a step-by-step guide:

Prerequisites:

1. Ensure you have Terraform installed.
2. Ensure you have AWS CLI configured.
3. Ensure you have an existing EKS cluster managed by Terraform.

1. Find the Latest AMI ID:

1. Find the Latest EKS-Optimized AMI ID: Check the latest AMI IDs in the Amazon EKS optimized AMI page.

2. Update Terraform Configuration:

1.Update Launch Template (for Managed Node Groups):

1. If you are using a launch template for your node group, update the launch template with the new AMI ID.
2. Update your Terraform code to use the new AMI ID.

resource "aws_launch_template" "example" {
  name_prefix   = "example"

  # Other configurations

  image_id = "ami-xxxxxxxxxxxxxxxxx"  # Update with the new AMI ID

  # Other configurations
}

2. Update Launch Configuration (for Self-Managed Node Groups):

• If you are using a launch configuration, update it with the new AMI ID.

resource "aws_launch_configuration" "example" {
  name          = "example"
  image_id      = "ami-xxxxxxxxxxxxxxxxx"  # Update with the new AMI ID
  instance_type = "t2.micro"

  # Other configurations
}

3. Update Node Group Configuration:

• If you are managing your node groups directly in Terraform, update the node group resource to use the new launch template or launch configuration.

resource "aws_eks_node_group" "example" {
  cluster_name    = aws_eks_cluster.example.name
  node_group_name = "example"

  # Other configurations

  launch_template {
    id      = aws_launch_template.example.id
    version = "$Latest"  # Use the latest version of the launch template
  }

  # Other configurations
}

4. Apply Terraform Changes:

1.Plan the Changes:

• Run terraform plan to see the changes that will be applied.

terraform plan

2. Apply Changes:

Run terraform apply to apply the changes

terraform apply