Terraform Samples

# AWS Provider configuration
terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 5.0"
    }
  }
}

provider "aws" {
  region = var.aws_region
}

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

variable "instance_type" {
  description = "EC2 instance type"
  type        = string
  default     = "t3.micro"
}

variable "ami_id" {
  description = "Amazon Machine Image ID"
  type        = string
  default     = "ami-0c02fb55956c7d316"
}

# Security group
resource "aws_security_group" "web_sg" {
  name        = "web-security-group"
  description = "Allow HTTP/HTTPS and SSH traffic"

  ingress {
    description = "HTTP from anywhere"
    from_port   = 80
    to_port     = 80
    protocol    = "tcp"
    cidr_blocks = ["0.0.0.0/0"]
  }

  ingress {
    description = "HTTPS from anywhere"
    from_port   = 443
    to_port     = 443
    protocol    = "tcp"
    cidr_blocks = ["0.0.0.0/0"]
  }

  ingress {
    description = "SSH from anywhere"
    from_port   = 22
    to_port     = 22
    protocol    = "tcp"
    cidr_blocks = ["0.0.0.0/0"]
  }

  egress {
    from_port   = 0
    to_port     = 0
    protocol    = "-1"
    cidr_blocks = ["0.0.0.0/0"]
  }

  tags = {
    Name = "web-sg"
    Env  = "production"
  }
}

# EC2 Instance
resource "aws_instance" "web_server" {
  ami                    = var.ami_id
  instance_type          = var.instance_type
  vpc_security_group_ids = [aws_security_group.web_sg.id]

  user_data = base64encode(<<-EOF
              #!/bin/bash
              yum update -y
              yum install -y httpd
              systemctl start httpd
              systemctl enable httpd
              echo "<h1>Hello from Terraform!</h1>" > /var/www/html/index.html
              EOF
  )

  tags = {
    Name        = "WebServer"
    Environment = "Production"
    ManagedBy   = "Terraform"
  }
}

# Output
output "instance_public_ip" {
  description = "Public IP address of the EC2 instance"
  value       = aws_instance.web_server.public_ip
}

output "instance_id" {
  description = "ID of the EC2 instance"
  value       = aws_instance.web_server.id
}

# Multi-tier Web Application Architecture
terraform {
  required_version = ">= 1.0"
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 5.0"
    }
  }
}

provider "aws" {
  region = var.aws_region
}

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

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

variable "db_password" {
  description = "Database password"
  type        = string
  sensitive   = true
}

# VPC Configuration
resource "aws_vpc" "main" {
  cidr_block           = "10.0.0.0/16"
  enable_dns_support   = true
  enable_dns_hostnames = true

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

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

  tags = {
    Name = "main-igw"
  }
}

# Public Subnets
resource "aws_subnet" "public" {
  count = 2

  vpc_id                  = aws_vpc.main.id
  cidr_block              = cidrsubnet(aws_vpc.main.cidr_block, 8, count.index)
  availability_zone       = data.aws_availability_zones.available.names[count.index]
  map_public_ip_on_launch = true

  tags = {
    Name = "public-subnet"
  }
}

# Private Subnets
resource "aws_subnet" "private" {
  count = 2

  vpc_id            = aws_vpc.main.id
  cidr_block        = cidrsubnet(aws_vpc.main.cidr_block, 8, count.index + 10)
  availability_zone = data.aws_availability_zones.available.names[count.index]

  tags = {
    Name = "private-subnet"
  }
}

# Data source for availability zones
data "aws_availability_zones" "available" {
  state = "available"
}

# Route Tables
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 = "public-rt"
  }
}

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

# Security Groups
resource "aws_security_group" "web_sg" {
  name_prefix = "web-sg-"
  vpc_id      = aws_vpc.main.id

  ingress {
    description = "HTTP"
    from_port   = 80
    to_port     = 80
    protocol    = "tcp"
    cidr_blocks = ["0.0.0.0/0"]
  }

  egress {
    from_port   = 0
    to_port     = 0
    protocol    = "-1"
    cidr_blocks = ["0.0.0.0/0"]
  }

  tags = {
    Name = "web-sg"
  }
}

# Load Balancer
resource "aws_lb" "web" {
  name               = "web-lb"
  internal           = false
  load_balancer_type = "application"
  security_groups    = [aws_security_group.web_sg.id]
  subnets            = aws_subnet.public[*].id

  tags = {
    Environment = var.environment
  }
}

resource "aws_lb_target_group" "web" {
  name     = "web-tg"
  port     = 80
  protocol = "HTTP"
  vpc_id   = aws_vpc.main.id

  health_check {
    enabled             = true
    healthy_threshold   = 2
    interval            = 30
    matcher             = "200"
    path                = "/"
    port                = "traffic-port"
    protocol            = "HTTP"
    timeout             = 5
    unhealthy_threshold = 2
  }
}

# RDS Database
resource "aws_db_subnet_group" "main" {
  name       = "main-db-subnet-group"
  subnet_ids = aws_subnet.private[*].id

  tags = {
    Name = "DB subnet group"
  }
}

resource "aws_db_instance" "main" {
  identifier     = "web-app-db"
  engine         = "mysql"
  engine_version = "8.0"
  instance_class = "db.t3.micro"

  allocated_storage     = 20
  max_allocated_storage = 100
  storage_type          = "gp2"
  storage_encrypted     = true

  db_name  = "webapp"
  username = "admin"
  password = var.db_password

  db_subnet_group_name = aws_db_subnet_group.main.name

  backup_retention_period = 7
  backup_window          = "03:00-04:00"
  maintenance_window     = "sun:04:00-sun:05:00"

  skip_final_snapshot = true

  tags = {
    Environment = var.environment
  }
}

# Outputs
output "load_balancer_dns" {
  description = "DNS name of the load balancer"
  value       = aws_lb.web.dns_name
}

output "database_endpoint" {
  description = "RDS database endpoint"
  value       = aws_db_instance.main.endpoint
  sensitive   = true
}

# EKS Kubernetes Cluster Deployment
terraform {
  required_version = ">= 1.0"
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 5.0"
    }
    kubernetes = {
      source  = "hashicorp/kubernetes"
      version = "~> 2.20"
    }
    helm = {
      source  = "hashicorp/helm"
      version = "~> 2.10"
    }
  }
}

provider "aws" {
  region = var.aws_region
}

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

variable "cluster_name" {
  description = "EKS cluster name"
  type        = string
  default     = "production-cluster"
}

variable "cluster_version" {
  description = "Kubernetes version"
  type        = string
  default     = "1.28"
}

variable "node_group_desired_size" {
  description = "Desired number of worker nodes"
  type        = number
  default     = 3
}

variable "node_group_max_size" {
  description = "Maximum number of worker nodes"
  type        = number
  default     = 6
}

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

# Data sources
data "aws_availability_zones" "available" {
  state = "available"
}

# VPC for EKS
resource "aws_vpc" "eks" {
  cidr_block           = "10.0.0.0/16"
  enable_dns_hostnames = true
  enable_dns_support   = true

  tags = {
    Name = "eks-vpc"
  }
}

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

  tags = {
    Name = "eks-igw"
  }
}

# Public Subnets
resource "aws_subnet" "public" {
  count = 3

  vpc_id                  = aws_vpc.eks.id
  cidr_block              = cidrsubnet(aws_vpc.eks.cidr_block, 8, count.index)
  availability_zone       = data.aws_availability_zones.available.names[count.index]
  map_public_ip_on_launch = true

  tags = {
    Name                                        = "eks-public-subnet"
    "kubernetes.io/cluster/${var.cluster_name}" = "shared"
    "kubernetes.io/role/elb"                   = "1"
  }
}

# Private Subnets
resource "aws_subnet" "private" {
  count = 3

  vpc_id            = aws_vpc.eks.id
  cidr_block        = cidrsubnet(aws_vpc.eks.cidr_block, 8, count.index + 10)
  availability_zone = data.aws_availability_zones.available.names[count.index]

  tags = {
    Name                                        = "eks-private-subnet"
    "kubernetes.io/cluster/${var.cluster_name}" = "shared"
    "kubernetes.io/role/internal-elb"          = "1"
  }
}

# NAT Gateway
resource "aws_eip" "nat" {
  count = 3
  vpc   = true

  tags = {
    Name = "eks-nat-eip"
  }

  depends_on = [aws_internet_gateway.eks]
}

resource "aws_nat_gateway" "eks" {
  count         = 3
  allocation_id = aws_eip.nat[count.index].id
  subnet_id     = aws_subnet.public[count.index].id

  tags = {
    Name = "eks-nat-gw"
  }

  depends_on = [aws_internet_gateway.eks]
}

# Route Tables
resource "aws_route_table" "public" {
  vpc_id = aws_vpc.eks.id

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

  tags = {
    Name = "eks-public-rt"
  }
}

resource "aws_route_table" "private" {
  count  = 3
  vpc_id = aws_vpc.eks.id

  route {
    cidr_block     = "0.0.0.0/0"
    nat_gateway_id = aws_nat_gateway.eks[count.index].id
  }

  tags = {
    Name = "eks-private-rt"
  }
}

resource "aws_route_table_association" "public" {
  count          = 3
  subnet_id      = aws_subnet.public[count.index].id
  route_table_id = aws_route_table.public.id
}

resource "aws_route_table_association" "private" {
  count          = 3
  subnet_id      = aws_subnet.private[count.index].id
  route_table_id = aws_route_table.private[count.index].id
}

# IAM Role for EKS Cluster
resource "aws_iam_role" "eks_cluster_role" {
  name = "eks-cluster-role"

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

  tags = {
    Name = "eks-cluster-role"
  }
}

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

# EKS Cluster
resource "aws_eks_cluster" "main" {
  name     = var.cluster_name
  role_arn = aws_iam_role.eks_cluster_role.arn
  version  = var.cluster_version

  vpc_config {
    subnet_ids = concat(aws_subnet.public[*].id, aws_subnet.private[*].id)
  }

  depends_on = [
    aws_iam_role_policy_attachment.eks_cluster_policy
  ]

  tags = {
    Name = var.cluster_name
  }
}

# IAM Role for EKS Node Group
resource "aws_iam_role" "eks_node_role" {
  name = "eks-node-role"

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

  tags = {
    Name = "eks-node-role"
  }
}

resource "aws_iam_role_policy_attachment" "eks_worker_node_policy" {
  policy_arn = "arn:aws:iam::aws:policy/AmazonEKSWorkerNodePolicy"
  role       = aws_iam_role.eks_node_role.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_role.name
}

resource "aws_iam_role_policy_attachment" "ec2_container_registry_readonly" {
  policy_arn = "arn:aws:iam::aws:policy/AmazonEC2ContainerRegistryReadOnly"
  role       = aws_iam_role.eks_node_role.name
}

# EKS Node Group
resource "aws_eks_node_group" "main" {
  cluster_name    = aws_eks_cluster.main.name
  node_group_name = "main-node-group"
  node_role_arn   = aws_iam_role.eks_node_role.arn
  subnet_ids      = aws_subnet.private[*].id

  scaling_config {
    desired_size = var.node_group_desired_size
    max_size     = var.node_group_max_size
    min_size     = var.node_group_min_size
  }

  instance_types = ["t3.medium"]

  depends_on = [
    aws_iam_role_policy_attachment.eks_worker_node_policy,
    aws_iam_role_policy_attachment.eks_cni_policy,
    aws_iam_role_policy_attachment.ec2_container_registry_readonly
  ]

  tags = {
    Name = "main-node-group"
  }
}

# Kubernetes Provider
provider "kubernetes" {
  host                   = aws_eks_cluster.main.endpoint
  cluster_ca_certificate = base64decode(aws_eks_cluster.main.certificate_authority[0].data)

  exec {
    api_version = "client.authentication.k8s.io/v1beta1"
    command     = "aws"
    args        = ["eks", "get-token", "--cluster-name", aws_eks_cluster.main.name]
  }
}

# Deploy sample application
resource "kubernetes_namespace" "app" {
  metadata {
    name = "sample-app"
  }
}

resource "kubernetes_deployment" "sample_app" {
  metadata {
    name      = "sample-app"
    namespace = kubernetes_namespace.app.metadata[0].name
  }

  spec {
    replicas = 3

    selector {
      match_labels = {
        app = "sample-app"
      }
    }

    template {
      metadata {
        labels = {
          app = "sample-app"
        }
      }

      spec {
        container {
          image = "nginx:1.21"
          name  = "nginx"

          port {
            container_port = 80
          }

          resources {
            limits = {
              cpu    = "200m"
              memory = "256Mi"
            }
            requests = {
              cpu    = "100m"
              memory = "128Mi"
            }
          }
        }
      }
    }
  }
}

# Outputs
output "cluster_endpoint" {
  description = "Endpoint for EKS control plane"
  value       = aws_eks_cluster.main.endpoint
}

output "cluster_name" {
  description = "Kubernetes Cluster Name"
  value       = aws_eks_cluster.main.name
}

output "configure_kubectl" {
  description = "Configure kubectl command"
  value       = "aws eks update-kubeconfig --region us-east-1 --name production-cluster"
}