How to fix Error: Error creating EKS Cluster: ResourceInUseException in Terraform

First, check if a cluster with the same name actually exists in your AWS account:

aws eks list-clusters --region us-east-1

Replace us-east-1 with your target region. If your cluster name appears in the list, the cluster exists. Check the cluster status - if it shows "DELETING", you must wait until it completes deletion (typically 15-30 minutes) before trying to create a new cluster with the same name.

Verify your Terraform state hasn't diverged from actual AWS resources:

terraform refresh
terraform plan

This will sync your local state with AWS and show what Terraform thinks should exist. If the plan shows the cluster being created but it actually exists in AWS, your state is out of sync.

If the cluster exists in AWS but not in your Terraform state, import it:

terraform import aws_eks_cluster.main my-cluster-name

Replace aws_eks_cluster.main with your actual resource address and my-cluster-name with your cluster name. This adds the existing AWS resource to your Terraform state, preventing duplicate creation attempts.

If you recently deleted a cluster, AWS needs time to fully clean up all associated resources (security groups, networking, IAM roles). Wait 15-30 minutes after deletion completes before attempting to create a new cluster with the same name:

aws eks describe-cluster --name my-cluster-name --region us-east-1

If this returns an error that the cluster doesn't exist, it's safe to create a new one with that name.

If you need to proceed immediately, modify your Terraform configuration to use a different cluster name:

resource "aws_eks_cluster" "main" {
  name            = "my-cluster-new-v2"  # Changed from my-cluster
  role_arn        = aws_iam_role.cluster.arn
  vpc_config {
    subnet_ids = var.subnet_ids
  }
}

After the problematic resources are fully cleaned up, you can rename it back to your original name.

Check AWS CloudFormation for any stuck stacks related to EKS:

aws cloudformation list-stacks --stack-status-filter CREATE_FAILED DELETE_FAILED

Look for any stacks with names matching your cluster. If found, attempt deletion:

aws cloudformation delete-stack --stack-name problematic-stack-name

If the stack refuses to delete, you may need to delete associated resources manually (security groups, network interfaces, IAM roles) first.