Terraform setup for web application infrastructure

Terraform Infrastructure Setup

Terraform is an Infrastructure as Code tool from HashiCorp. Describes cloud resources in HCL, manages their lifecycle: creation, modification, deletion. Supports AWS, GCP, Azure, Hetzner, DigitalOcean and 1000+ providers.

Project structure

infra/
├── main.tf           # main resources
├── variables.tf      # input variables
├── outputs.tf        # output values
├── versions.tf       # provider versions
├── backend.tf        # state storage
├── modules/
│   ├── app-server/
│   ├── database/
│   └── networking/
└── environments/
    ├── staging/
    │   └── terraform.tfvars
    └── production/
        └── terraform.tfvars

versions.tf

terraform {
  required_version = ">= 1.6"

  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 5.0"
    }
    cloudflare = {
      source  = "cloudflare/cloudflare"
      version = "~> 4.0"
    }
  }

  backend "s3" {
    bucket         = "myapp-terraform-state"
    key            = "production/terraform.tfstate"
    region         = "eu-west-1"
    encrypt        = true
    dynamodb_table = "terraform-locks"
  }
}

Typical AWS infrastructure

# networking.tf
resource "aws_vpc" "main" {
  cidr_block           = "10.0.0.0/16"
  enable_dns_hostnames = true
  tags = { Name = "myapp-vpc" }
}

resource "aws_subnet" "public" {
  count             = 2
  vpc_id            = aws_vpc.main.id
  cidr_block        = "10.0.${count.index}.0/24"
  availability_zone = data.aws_availability_zones.available.names[count.index]
  map_public_ip_on_launch = true
}

resource "aws_subnet" "private" {
  count      = 2
  vpc_id     = aws_vpc.main.id
  cidr_block = "10.0.${count.index + 10}.0/24"
  availability_zone = data.aws_availability_zones.available.names[count.index]
}

# ECS Cluster
resource "aws_ecs_cluster" "main" {
  name = "myapp-cluster"

  setting {
    name  = "containerInsights"
    value = "enabled"
  }
}

# RDS PostgreSQL
resource "aws_db_instance" "main" {
  identifier           = "myapp-db"
  engine               = "postgres"
  engine_version       = "16.1"
  instance_class       = "db.t3.medium"
  allocated_storage    = 100
  storage_type         = "gp3"
  storage_encrypted    = true

  db_name  = "myapp"
  username = "myapp"
  password = var.db_password

  vpc_security_group_ids = [aws_security_group.db.id]
  db_subnet_group_name   = aws_db_subnet_group.main.name

  backup_retention_period = 7
  skip_final_snapshot     = false
  final_snapshot_identifier = "myapp-final-snapshot"

  performance_insights_enabled = true

  tags = local.common_tags
}

# ElastiCache Redis
resource "aws_elasticache_cluster" "redis" {
  cluster_id           = "myapp-redis"
  engine               = "redis"
  node_type            = "cache.t3.micro"
  num_cache_nodes      = 1
  parameter_group_name = "default.redis7"
  port                 = 6379
  subnet_group_name    = aws_elasticache_subnet_group.main.name
  security_group_ids   = [aws_security_group.redis.id]
}

# Application Load Balancer
resource "aws_lb" "main" {
  name               = "myapp-alb"
  internal           = false
  load_balancer_type = "application"
  subnets            = aws_subnet.public[*].id
  security_groups    = [aws_security_group.alb.id]

  access_logs {
    bucket  = aws_s3_bucket.logs.bucket
    enabled = true
  }
}

Variables and environments

# variables.tf
variable "environment" {
  description = "Environment name (staging/production)"
  type        = string
}

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

variable "app_instance_type" {
  type    = string
  default = "t3.medium"
}

# environments/production/terraform.tfvars
environment       = "production"
app_instance_type = "c5.xlarge"

App server module

# modules/app-server/main.tf
variable "name" {}
variable "instance_type" {}
variable "vpc_id" {}
variable "subnet_ids" { type = list(string) }

resource "aws_launch_template" "app" {
  name_prefix   = "${var.name}-"
  image_id      = data.aws_ami.ubuntu.id
  instance_type = var.instance_type
  # ...
}

resource "aws_autoscaling_group" "app" {
  name             = var.name
  min_size         = 2
  max_size         = 10
  desired_capacity = 2
  vpc_zone_identifier = var.subnet_ids
  # ...
}

output "asg_name" {
  value = aws_autoscaling_group.app.name
}

Working with Terraform

# Initialization
terraform init

# Planning
terraform plan -var-file=environments/production/terraform.tfvars

# Apply
terraform apply -var-file=environments/production/terraform.tfvars

# Only specific resource
terraform apply -target=aws_db_instance.main

# Destroy (be careful!)
terraform destroy -var-file=environments/staging/terraform.tfvars

Timeline

Basic AWS infrastructure (VPC, ECS, RDS, ALB): 5–7 days. Full infrastructure with modules, staging/prod: 10–14 days.