Terraform基础设施即代码

什么是Terraform

Terraform是HashiCorp开发的基础设施即代码（IaC）工具，用于定义和管理云资源。

核心特点

• 声明式配置
• 多云支持
• 计划和预览变更
• 依赖关系管理
• 状态管理

安装Terraform

# macOS
brew install terraform

# Linux
wget https://releases.hashicorp.com/terraform/1.5.0/terraform_1.5.0_linux_amd64.zip
unzip terraform_1.5.0_linux_amd64.zip
sudo mv terraform /usr/local/bin/

# 验证
terraform --version

基本使用

初始化

# 初始化工作目录
terraform init

# 下载提供商插件
terraform get

编写配置

# main.tf
terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 5.0"
    }
  }
}

provider "aws" {
  region = "us-west-2"
}

resource "aws_instance" "web" {
  ami           = "ami-0c55b159cbfafe1f0"
  instance_type = "t2.micro"
  
  tags = {
    Name = "web-server"
  }
}

常用命令

# 预览变更
terraform plan

# 应用变更
terraform apply

# 销毁资源
terraform destroy

# 查看状态
terraform show

# 列出资源
terraform state list

状态管理

本地状态

# 查看状态
terraform state show aws_instance.web

# 移动资源
terraform state mv aws_instance.web aws_instance.new_name

# 移除资源
terraform state rm aws_instance.web

# 导入现有资源
terraform import aws_instance.web i-1234567890abcdef0

远程状态

# 远程状态存储
terraform {
  backend "s3" {
    bucket = "my-terraform-state"
    key    = "prod/terraform.tfstate"
    region = "us-west-2"
  }
}

实践：创建AWS基础设施

# main.tf
terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 5.0"
    }
  }
  
  backend "s3" {
    bucket = "my-terraform-state"
    key    = "infra/terraform.tfstate"
    region = "us-west-2"
  }
}

provider "aws" {
  region = var.aws_region
}

# VPC
resource "aws_vpc" "main" {
  cidr_block = "10.0.0.0/16"
  
  tags = {
    Name = "main-vpc"
  }
}

# 子网
resource "aws_subnet" "public" {
  vpc_id                  = aws_vpc.main.id
  cidr_block              = "10.0.1.0/24"
  availability_zone       = "us-west-2a"
  map_public_ip_on_launch = true
  
  tags = {
    Name = "public-subnet"
  }
}

# 安全组
resource "aws_security_group" "web" {
  name        = "web-sg"
  description = "Web server security group"
  vpc_id      = aws_vpc.main.id
  
  ingress {
    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"]
  }
}

# EC2实例
resource "aws_instance" "web" {
  ami                    = "ami-0c55b159cbfafe1f0"
  instance_type          = "t2.micro"
  subnet_id              = aws_subnet.public.id
  vpc_security_group_ids = [aws_security_group.web.id]
  
  user_data = <<-EOF
              #!/bin/bash
              yum update -y
              yum install httpd -y
              systemctl start httpd
              systemctl enable httpd
              EOF
  
  tags = {
    Name = "web-server"
  }
}

变量和输出

# variables.tf
variable "aws_region" {
  description = "AWS region"
  default     = "us-west-2"
}

variable "instance_type" {
  description = "EC2 instance type"
  default     = "t2.micro"
}

# outputs.tf
output "instance_id" {
  value = aws_instance.web.id
}

output "public_ip" {
  value = aws_instance.web.public_ip
}

模块

# modules/vpc/main.tf
resource "aws_vpc" "this" {
  cidr_block = var.cidr_block
}

# 使用模块
module "vpc" {
  source = "./modules/vpc"
  cidr_block = "10.0.0.0/16"
}

总结

Terraform是基础设施即代码的标准工具。通过声明式配置，可以实现基础设施的版本化管理和自动化部署。