# Terraform Modular EKS + Istio — Part 5

CSI Drivers (How Storage Actually Works in EKS) So far: VPC → network IAM → permissions EKS → control plane Nodes → compute Now comes the part many people ignore: 👉 Storage Without this: Pods can’t persist data Databases won’t work Logs disappear on restart This module installs CSI drivers , which allow Kubernetes to use AWS storage. 📂 Module Files modules/csi-driver/ ├── main.tf ├── variables.tf └── outputs.tf 📄 variables.tf variable "cluster_name" { description = "Name of the EKS cluster" type = string } variable "ebs_csi_role_arn" { description = "IAM role ARN for EBS CSI driver" type = string } variable "s3_csi_role_arn" { description = "IAM role ARN for S3 CSI driver" type = string } variable "node_group_dependency" { description = "Node group dependency to ensure nodes exist first" type = any } 🧠 What these inputs mean cluster_name → where to install addons ebs_csi_role_arn → IAM role for EBS driver s3_csi_role_arn → IAM role for S3 driver node_group_dependency → ensures nodes ex