EKS Cluster Using Module

• Modules are reusable, self-contained Terraform configurations.

• Help organize, simplify, and standardize infrastructure code.

• Used like functions: define once, use many times.

• Can be local, from Terraform Registry, or remote sources (e.g., GitHub).

• Improve code reusability, maintainability, and collaboration in teams.

  Step 2: Write Terraform Code for VPC and EKS

You can split your code by resource type or keep it in a single main.tf for simplicity.

VPC Setup (Basic) using Module

module "vpc" {
  source = "terraform-aws-modules/vpc/aws"

  name = "pv-vpc"
  cidr = "10.0.0.0/16"

  azs             = ["us-east-1a", "us-east-1b"]
  private_subnets = ["10.0.1.0/24", "10.0.2.0/24"]
  public_subnets  = ["10.0.101.0/24", "10.0.102.0/24"]

  enable_nat_gateway = true
  enable_vpn_gateway = true

  tags = {
    Terraform = "true"
  }
}

locals.tf (Optional: can be inside main.tf if preferred)

locals {
    name = "pv-eks-cluster"
    vpc_cidr = "10.0.0.0/16"
    region = "us-east-2"
    azs   = ["us-east-2a", "us-east-2b"]
    private_subnets = ["10.0.1.0/24", "10.0.2.0/24"]
    public_subnets  = ["10.0.101.0/24", "10.0.102.0/24"]
    intra_subnets = ["10.0.5.0/24", "10.0.6.0/24"]
    env = "dev"
}

Using a Module (EKS)

Instead of writing all the EKS cluster logic manually, you can use a community-maintained module like this:

module "eks" {
    #import the module template
  source  = "terraform-aws-modules/eks/aws"

  #cluster info control-plane
  cluster_name    = local.name
  cluster_endpoint_public_access = true

  vpc_id     = module.vpc.vpc_id
  subnet_ids = module.vpc.private_subnets

  #control plane network
  control_plane_subnet_ids = module.vpc.intra_subnets

  cluster_addons = {
        vpc-cni = {
            most_recent = true
        }
        kube-proxy = {
            most_recent = true
        }
        coredns = {
            most_recent = true
        }

      }

   # EKS Managed Node Group(s)
  eks_managed_node_group_defaults = {
        instance_types = ["t2.medium"]
        attach_cluster_primary_security_group = true
  }


  eks_managed_node_groups = {
      eks-node-group = {
      instance_types = ["t2.medium"]

      min_size     = 1
      max_size     = 2
      desired_size = 1

      capacity_type = "SPOT"
    }
  }

  tags = {
    Environment = local.env
    Terraform   = "true"
  }
}

Here:

• source points to the module location (Terraform Registry)

• The rest are input variables required by the module

terraform.tf

terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = ">= 5.0.0"  # or latest stable version
    }
  }
}

providers.tf

provider "aws" {
    region = local.region
}

Step 3: Initialize and Apply Terraform

Open your terminal inside VS Code and run:

terraform init
terraform plan
terraform apply

Type yes to confirm the apply.

Finally, you can see the instance in the EKS on AWS

Happy learning :)