Using Published Modules

ใช้ module สำเร็จรูปจาก Terraform Registry — ไม่ต้องเขียนเอง

Terraform Registry Modules

registry.terraform.io/browse/modules — มี 17,000+ modules

Categories:

AWS — terraform-aws-modules/*
Google Cloud — terraform-google-modules/*
Azure — Azure/*
Generic — utilities, networking patterns

Popular Modules

AWS

Module	สิ่งที่ทำ
`terraform-aws-modules/vpc/aws`	VPC + subnets + NAT + routing
`terraform-aws-modules/eks/aws`	EKS cluster + node groups
`terraform-aws-modules/rds/aws`	RDS instance + security
`terraform-aws-modules/security-group/aws`	Security group with rules
`terraform-aws-modules/iam/aws`	IAM users, roles, policies
`terraform-aws-modules/lambda/aws`	Lambda function + IAM + logs
`terraform-aws-modules/cloudfront/aws`	CloudFront distribution
`terraform-aws-modules/alb/aws`	Application Load Balancer

GCP

Module	สิ่งที่ทำ
`terraform-google-modules/network/google`	VPC + subnets
`terraform-google-modules/kubernetes-engine/google`	GKE cluster
`terraform-google-modules/sql-db/google`	Cloud SQL

Azure

Module	สิ่งที่ทำ
`Azure/aks/azurerm`	AKS cluster
`Azure/vnet/azurerm`	Virtual Network
`Azure/network-security-group/azurerm`	NSG

ตัวอย่างใช้งาน: AWS VPC Module

main.tf
module "vpc" {
  source  = "terraform-aws-modules/vpc/aws"
  version = "5.13.0"

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

  azs             = ["ap-southeast-1a", "ap-southeast-1b", "ap-southeast-1c"]
  private_subnets = ["10.0.1.0/24", "10.0.2.0/24", "10.0.3.0/24"]
  public_subnets  = ["10.0.101.0/24", "10.0.102.0/24", "10.0.103.0/24"]

  enable_nat_gateway = true
  single_nat_gateway = true   # cheaper for dev

  enable_dns_hostnames = true
  enable_dns_support   = true

  tags = {
    Environment = "production"
    Terraform   = "true"
  }
}

# ใช้ output ของ module
resource "aws_instance" "web" {
  ami           = "ami-12345"
  instance_type = "t3.micro"
  subnet_id     = module.vpc.public_subnets[0]

  vpc_security_group_ids = [module.vpc.default_security_group_id]
}

ตัวอย่าง: EKS Cluster

module "eks" {
  source  = "terraform-aws-modules/eks/aws"
  version = "20.24.0"

  cluster_name    = "my-cluster"
  cluster_version = "1.30"

  cluster_endpoint_public_access = true

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

  eks_managed_node_groups = {
    default = {
      min_size     = 1
      max_size     = 5
      desired_size = 2

      instance_types = ["t3.medium"]
      capacity_type  = "ON_DEMAND"
    }
  }

  tags = {
    Environment = "production"
  }
}

ตัวอย่าง: RDS PostgreSQL

module "db" {
  source  = "terraform-aws-modules/rds/aws"
  version = "6.10.0"

  identifier = "my-postgres"

  engine            = "postgres"
  engine_version    = "15.4"
  instance_class    = "db.t3.micro"
  allocated_storage = 20

  db_name  = "mydb"
  username = "admin"
  port     = 5432

  vpc_security_group_ids = [aws_security_group.db.id]
  db_subnet_group_name   = module.vpc.database_subnet_group

  backup_retention_period = 7
  backup_window           = "03:00-06:00"

  performance_insights_enabled = true
  create_monitoring_role       = true
  monitoring_interval          = 60

  deletion_protection = true
}

วิธีหา Module ที่เหมาะ

1. Search ใน Registry

https://registry.terraform.io/search?q=eks

2. ดูเกณฑ์

⭐ Downloads — ยิ่งเยอะยิ่ง mature
📅 Last updated — recent = active maintenance
🏷️ Verified badge (จาก HashiCorp Partner)
📖 Documentation ครบไหม
🐛 Issues ใน GitHub — open vs closed ratio

3. ตัวอย่าง: เลือกระหว่าง 2 modules

Module A: `terraform-aws-modules/vpc/aws`

Downloads: 600M+
Verified ✓
Last update: 2 weeks ago
Issues: 50 open, 2000 closed

→ ใช้ตัวนี้

Module B: `random-user/aws-vpc-thing`

Downloads: 100
Last update: 2 ปีที่แล้ว
Issues: 30 open, 5 closed

→ Avoid

อ่าน Module Documentation

ทุก module ใน Registry มีหน้า docs:

https://registry.terraform.io/modules/terraform-aws-modules/vpc/aws/latest

ตรวจ:

Inputs — variables ที่ต้องส่ง
Outputs — ค่าที่ module return
Examples — ตัวอย่างใช้งานจริง
Submodules — module ย่อย (บาง module มี)

Submodules

บาง module มี submodules:

# Main module
module "vpc" {
  source  = "terraform-aws-modules/vpc/aws"
  version = "5.13.0"
  # ...
}

# Submodule (network ACL only)
module "vpc_acl" {
  source  = "terraform-aws-modules/vpc/aws//modules/network-acls"
  version = "5.13.0"

  vpc_id                = module.vpc.vpc_id
  private_subnets_cidrs = module.vpc.private_subnets_cidr_blocks
}

// คือ subdirectory ใน module repo

Module Constraints

module "vpc" {
  source  = "terraform-aws-modules/vpc/aws"
  version = "~> 5.13"   # ⭐ pessimistic — allow patch + minor up to 5.x
}

Version Operators (recap)

Operator	ตัวอย่าง
`=`	`5.13.0`
`>=`	`>= 5.0`
`~>`	`~> 5.13` (5.13.x or 5.x)
`< >=`	`>= 5.0, < 6.0`

Update Module Version

# 1. แก้ version ใน .tf
# 2. Re-init
terraform init -upgrade

# 3. Plan ดู diff
terraform plan

Private Modules

GitHub Private Repo

module "internal" {
  source = "git::ssh://[email protected]/myorg/private-modules.git//vpc?ref=v1.0"
}

ต้องมี SSH key ของ GitHub ที่ access repo ได้

Terraform Cloud / Enterprise (Private Registry)

module "internal" {
  source  = "app.terraform.io/my-org/vpc/aws"
  version = "1.0.0"
}

S3 Bucket (private)

module "internal" {
  source = "s3::https://s3-bucket.s3.amazonaws.com/modules/vpc-1.0.zip"
}

Override Module Source

ใช้ตอน develop module — ทดสอบ local copy:

module "vpc" {
  source  = "terraform-aws-modules/vpc/aws"
  version = "5.13.0"
  # ...
}

.terraformrc หรือ override.tf
provider_installation {
  dev_overrides {
    "terraform-aws-modules/vpc/aws" = "/Users/me/code/local-vpc-fork"
  }
}

Best Practices

✅ DO:
- ใช้ verified modules ใน prod (HashiCorp Partner)
- Pin specific version (~> 5.13)
- อ่าน CHANGELOG ก่อน update
- ทดสอบใน dev ก่อน prod
- Reference module documentation ใน comments

❌ DON'T:
- ห้าม use module โดยไม่อ่าน docs
- ห้าม pin master/main branch
- ห้าม skip review เมื่อ update
- ห้ามใช้ unmaintained module (last update > 1 ปี)

ตัวอย่าง Real-World

main.tf
# Network
module "vpc" {
  source  = "terraform-aws-modules/vpc/aws"
  version = "5.13.0"

  name             = "${var.env}-vpc"
  cidr             = var.vpc_cidr
  azs              = data.aws_availability_zones.available.names
  private_subnets  = var.private_subnets
  public_subnets   = var.public_subnets
  database_subnets = var.database_subnets

  enable_nat_gateway = true
  single_nat_gateway = var.env != "prod"

  tags = local.common_tags
}

# Security Group
module "web_sg" {
  source  = "terraform-aws-modules/security-group/aws"
  version = "5.2.0"

  name        = "${var.env}-web-sg"
  description = "Allow HTTP/HTTPS from internet"
  vpc_id      = module.vpc.vpc_id

  ingress_cidr_blocks = ["0.0.0.0/0"]
  ingress_rules       = ["http-80-tcp", "https-443-tcp"]

  egress_rules = ["all-all"]

  tags = local.common_tags
}

# ALB
module "alb" {
  source  = "terraform-aws-modules/alb/aws"
  version = "9.11.0"

  name               = "${var.env}-alb"
  load_balancer_type = "application"

  vpc_id          = module.vpc.vpc_id
  subnets         = module.vpc.public_subnets
  security_groups = [module.web_sg.security_group_id]

  tags = local.common_tags
}

สรุป

Terraform Registry มี 17,000+ modules
ใช้ terraform-aws-modules/* สำหรับ AWS เป็นมาตรฐาน
Pin version (~> 5.13)
ตรวจ downloads, last update, verified badge
อ่าน Inputs / Outputs / Examples ใน docs ก่อนใช้
Private module ผ่าน GitHub / TFC / S3

ต่อไป → Creating Local Modules

Terraform Registry Modules​

Popular Modules​

AWS​

GCP​

Azure​

ตัวอย่างใช้งาน: AWS VPC Module​

ตัวอย่าง: EKS Cluster​

ตัวอย่าง: RDS PostgreSQL​

วิธีหา Module ที่เหมาะ​

1. Search ใน Registry​

2. ดูเกณฑ์​

3. ตัวอย่าง: เลือกระหว่าง 2 modules​

Module A: terraform-aws-modules/vpc/aws​

Module B: random-user/aws-vpc-thing​

อ่าน Module Documentation​

Submodules​

Module Constraints​

Version Operators (recap)​

Update Module Version​

Private Modules​

GitHub Private Repo​

Terraform Cloud / Enterprise (Private Registry)​

S3 Bucket (private)​

Override Module Source​

Best Practices​

ตัวอย่าง Real-World​

สรุป​