Create a Terraform project which Implements a VPC on AWS and deploys to EKS cluster.

In this Terraform project we will learn how to provisions a Virtual Private Cloud (VPC) on AWS, deploys an Amazon Elastic Kubernetes Service (EKS) cluster within that VPC, and provides associated networking and IAM resources.

In this I’ll create a well-organized Terraform configuration for an AWS VPC and EKS cluster, split into logical modules.

The complete project GitHub URl: https://github.com/Consultantsrihari/Create-a-Terraform-project-which-Implements-a-VPC-on-AWS-and-deploys-to-EKS-cluster..git

AWS VPC and EKS Terraform Configuration
**_

I. created a modular Terraform configuration that sets up:

_**Main.tf:

terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 5.0"
    }
  }
}

provider "aws" {
  region = var.aws_region
}

module "vpc" {
  source = "./modules/vpc"

  vpc_cidr           = var.vpc_cidr
  availability_zones = var.availability_zones
  environment        = var.environment
}

module "eks" {
  source = "./modules/eks"

  environment         = var.environment
  subnet_ids         = module.vpc.private_subnet_ids
  kubernetes_version = "1.27"

  node_desired_size  = 2
  node_max_size      = 4
  node_min_size      = 1
  node_instance_types = ["t3.medium"]
}

1. Variables.tf:

variable "aws_region" {
  description = "AWS region"
  type        = string
  default     = "us-east-1"
}

variable "environment" {
  description = "Environment name"
  type        = string
  default     = "dev"
}

variable "vpc_cidr" {
  description = "CIDR block for VPC"
  type        = string
  default     = "10.0.0.0/16"
}

variable "availability_zones" {
  description = "Availability zones"
  type        = list(string)
  default     = ["us-east-1a", "us-east-1b", "us-east-1c"]
}

1. Outputs.tf

output "vpc_id" {
  value = module.vpc.vpc_id
}

output "cluster_endpoint" {
  value = module.eks.cluster_endpoint
}

output "cluster_name" {
  value = module.eks.cluster_name
}

_

**II. A VPC module (modules/vpc) that creates:

_
**VPC with DNS support
Public and private subnets across multiple AZs
Internet Gateway
NAT Gateways
Route tables

main.tf

# VPC
resource "aws_vpc" "main" {
  cidr_block           = var.vpc_cidr
  enable_dns_hostnames = true
  enable_dns_support   = true

  tags = {
    Name        = "${var.environment}-vpc"
    Environment = var.environment
  }
}

# Public Subnets
resource "aws_subnet" "public" {
  count             = length(var.availability_zones)
  vpc_id            = aws_vpc.main.id
  cidr_block        = cidrsubnet(var.vpc_cidr, 8, count.index)
  availability_zone = var.availability_zones[count.index]

  map_public_ip_on_launch = true

  tags = {
    Name                                           = "${var.environment}-public-${var.availability_zones[count.index]}"
    Environment                                    = var.environment
    "kubernetes.io/cluster/${var.environment}-eks" = "shared"
    "kubernetes.io/role/elb"                       = 1
  }
}

# Private Subnets
resource "aws_subnet" "private" {
  count             = length(var.availability_zones)
  vpc_id            = aws_vpc.main.id
  cidr_block        = cidrsubnet(var.vpc_cidr, 8, count.index + length(var.availability_zones))
  availability_zone = var.availability_zones[count.index]

  tags = {
    Name                                           = "${var.environment}-private-${var.availability_zones[count.index]}"
    Environment                                    = var.environment
    "kubernetes.io/cluster/${var.environment}-eks" = "shared"
    "kubernetes.io/role/internal-elb"              = 1
  }
}

# Internet Gateway
resource "aws_internet_gateway" "main" {
  vpc_id = aws_vpc.main.id

  tags = {
    Name        = "${var.environment}-igw"
    Environment = var.environment
  }
}

# Elastic IP for NAT Gateway
resource "aws_eip" "nat" {
  domain = "vpc"

  tags = {
    Name        = "${var.environment}-nat-eip"
    Environment = var.environment
  }
}

# NAT Gateway
resource "aws_nat_gateway" "main" {
  allocation_id = aws_eip.nat.id
  subnet_id     = aws_subnet.public[0].id

  tags = {
    Name        = "${var.environment}-nat"
    Environment = var.environment
  }
}

# Public Route Table
resource "aws_route_table" "public" {
  vpc_id = aws_vpc.main.id

  route {
    cidr_block = "0.0.0.0/0"
    gateway_id = aws_internet_gateway.main.id
  }

  tags = {
    Name        = "${var.environment}-public-rt"
    Environment = var.environment
  }
}

# Private Route Table
resource "aws_route_table" "private" {
  vpc_id = aws_vpc.main.id

  route {
    cidr_block     = "0.0.0.0/0"
    nat_gateway_id = aws_nat_gateway.main.id
  }

  tags = {
    Name        = "${var.environment}-private-rt"
    Environment = var.environment
  }
}

# Route Table Associations
resource "aws_route_table_association" "public" {
  count          = length(var.availability_zones)
  subnet_id      = aws_subnet.public[count.index].id
  route_table_id = aws_route_table.public.id
}

resource "aws_route_table_association" "private" {
  count          = length(var.availability_zones)
  subnet_id      = aws_subnet.private[count.index].id
  route_table_id = aws_route_table.private.id
}

1. variables.tf

variable "vpc_cidr" {
  description = "CIDR block for VPC"
  type        = string
}

variable "availability_zones" {
  description = "Availability zones"
  type        = list(string)
}

variable "environment" {
  description = "Environment name"
  type        = string
}

1. Outputs.tf

output "vpc_id" {
  value = aws_vpc.main.id
}

output "public_subnet_ids" {
  value = aws_subnet.public[*].id
}

output "private_subnet_ids" {
  value = aws_subnet.private[*].id
}

**_

III. An EKS module (modules/eks) that creates:

_**
EKS cluster
Node group with autoscaling
Required IAM roles and policies

main.tf

resource "aws_eks_cluster" "main" {
  name     = "${var.environment}-eks"
  role_arn = aws_iam_role.eks_cluster.arn
  version  = var.kubernetes_version

  vpc_config {
    subnet_ids              = var.subnet_ids
    endpoint_private_access = true
    endpoint_public_access  = true
  }

  depends_on = [
    aws_iam_role_policy_attachment.eks_cluster_policy,
    aws_iam_role_policy_attachment.eks_service_policy,
  ]
}

# EKS Cluster IAM Role
resource "aws_iam_role" "eks_cluster" {
  name = "${var.environment}-eks-cluster"

  assume_role_policy = jsonencode({
    Version = "2012-10-17"
    Statement = [
      {
        Action = "sts:AssumeRole"
        Effect = "Allow"
        Principal = {
          Service = "eks.amazonaws.com"
        }
      }
    ]
  })
}

resource "aws_iam_role_policy_attachment" "eks_cluster_policy" {
  policy_arn = "arn:aws:iam::aws:policy/AmazonEKSClusterPolicy"
  role       = aws_iam_role.eks_cluster.name
}

resource "aws_iam_role_policy_attachment" "eks_service_policy" {
  policy_arn = "arn:aws:iam::aws:policy/AmazonEKSServicePolicy"
  role       = aws_iam_role.eks_cluster.name
}

# Node Group
resource "aws_eks_node_group" "main" {
  cluster_name    = aws_eks_cluster.main.name
  node_group_name = "${var.environment}-node-group"
  node_role_arn   = aws_iam_role.eks_node_group.arn
  subnet_ids      = var.subnet_ids

  scaling_config {
    desired_size = var.node_desired_size
    max_size     = var.node_max_size
    min_size     = var.node_min_size
  }

  instance_types = var.node_instance_types

  depends_on = [
    aws_iam_role_policy_attachment.eks_node_policy,
    aws_iam_role_policy_attachment.eks_cni_policy,
    aws_iam_role_policy_attachment.eks_container_registry,
  ]
}

# Node Group IAM Role
resource "aws_iam_role" "eks_node_group" {
  name = "${var.environment}-eks-node-group"

  assume_role_policy = jsonencode({
    Version = "2012-10-17"
    Statement = [
      {
        Action = "sts:AssumeRole"
        Effect = "Allow"
        Principal = {
          Service = "ec2.amazonaws.com"
        }
      }
    ]
  })
}

resource "aws_iam_role_policy_attachment" "eks_node_policy" {
  policy_arn = "arn:aws:iam::aws:policy/AmazonEKSWorkerNodePolicy"
  role       = aws_iam_role.eks_node_group.name
}

resource "aws_iam_role_policy_attachment" "eks_cni_policy" {
  policy_arn = "arn:aws:iam::aws:policy/AmazonEKS_CNI_Policy"
  role       = aws_iam_role.eks_node_group.name
}

resource "aws_iam_role_policy_attachment" "eks_container_registry" {
  policy_arn = "arn:aws:iam::aws:policy/AmazonEC2ContainerRegistryReadOnly"
  role       = aws_iam_role.eks_node_group.name
}

1. variables.tf

variable "environment" {
  description = "Environment name"
  type        = string
}

variable "subnet_ids" {
  description = "Subnet IDs for EKS cluster"
  type        = list(string)
}

variable "kubernetes_version" {
  description = "Kubernetes version"
  type        = string
  default     = "1.27"
}

variable "node_desired_size" {
  description = "Desired number of worker nodes"
  type        = number
  default     = 2
}

variable "node_max_size" {
  description = "Maximum number of worker nodes"
  type        = number
  default     = 4
}

variable "node_min_size" {
  description = "Minimum number of worker nodes"
  type        = number
  default     = 1
}

variable "node_instance_types" {
  description = "Instance types for worker nodes"
  type        = list(string)
  default     = ["t3.medium"]
}

1. Outputs.tf

output "cluster_endpoint" {
  value = aws_eks_cluster.main.endpoint
}

output "cluster_name" {
  value = aws_eks_cluster.main.name
}

output "cluster_certificate_authority_data" {
  value = aws_eks_cluster.main.certificate_authority[0].data
}

To use this configuration:
Initialize Terraform:

terraform init

Review the plan:

terraform plan
Apply the configuration:

terraform apply

The configuration uses variables with sensible defaults but can be customized through the terraform.tfvars file.

Key features:

Highly available setup across 3 AZs
Private subnets for EKS nodes
Public subnets for load balancers
Proper IAM roles and policies
Autoscaling node group
Proper tagging for EKS and AWS Load Balancer Controller
https://github.com/Consultantsrihari/Create-a-Terraform-project-which-Implements-a-VPC-on-AWS-and-deploys-to-EKS-cluster..git

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You’re welcome! Have a great time ahead! Enjoy your day!

Please Connect with me any doubts.

Mail: [e-mail]

LinkedIn: www.linkedin.com/in/

GitHub: https://github.com/Consultantsrihari

Medium: Sriharimalapati — Medium

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