Orphaned EKS nodegroup - Can't delete Auto EKS cluster

The node group might have an associated Auto Scaling Group (ASG) that's preventing deletion?. Even without delete permissions, you might be able to

1. Set the ASG desired/min/max capacity to 0 (if you have UpdateAutoScalingGroup permissions)
2. Wait a few minutes for it to reconcile
3. Retry the node group deletion

When you encounter a dependency loop while trying to delete an EKS cluster with a node group that can't be deleted, there are a few potential solutions you can try:

1. Update the EKS cluster networking configuration to remove the security groups that are blocking the deletion of the node groups. This approach can break the dependency loop because EKS will remove these security groups from the Network Interfaces as well.

2. If the issue is related to security groups attached to network interfaces managed by EKS (often owned by AWS account ID 392771493575), you may need to:

• Identify if any EFS mount targets are using the security group
• Remove the security group from the EFS network interface
• This can be done through the EFS console or AWS CLI by modifying the security groups associated with your EFS mount targets

3. If you're using a launch template for your node group and the reference template was deleted, you'll need to recreate the node group:

• Launch a new node group
• Verify all nodes are healthy and in the Ready state
• Drain your worker nodes
• Delete the original node group

If none of these approaches work, you may need to contact AWS Support as they can help resolve issues with orphaned resources that you don't have permissions to manage directly.
Sources
Loop dependency for deleting EKS node group | AWS re:Post
Delete EKS Node Group failed due to Security Group and ENI Dependency | AWS re:Post
Troubleshoot Amazon EKS managed node groups and launch template issues | AWS re:Post