引言

Terraform是基础设施即代码的标准工具。本文介绍Terraform的使用和实践。

一、Terraform基础

1.1 安装

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# Linux
wget https://releases.hashicorp.com/terraform/1.3.0/terraform_1.3.0_linux_amd64.zip
unzip terraform_1.3.0_linux_amd64.zip
mv terraform /usr/local/bin/

# 验证
terraform version

1.2 基本命令

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# 初始化
terraform init

# 格式化
terraform fmt

# 验证
terraform validate

# 计划
terraform plan

# 应用
terraform apply

# 销毁
terraform destroy

二、AWS资源管理

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# provider.tf
terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 4.0"
    }
  }
}

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

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

resource "aws_subnet" "public" {
  vpc_id     = aws_vpc.main.id
  cidr_block = "10.0.1.0/24"
  
  tags = {
    Name = "public-subnet"
  }
}

# ec2.tf
resource "aws_instance" "web" {
  count         = 2
  ami           = "ami-0c55b159cbfafe1f0"
  instance_type = "t2.micro"
  subnet_id     = aws_subnet.public.id
  
  tags = {
    Name = "web-${count.index}"
  }
}

三、变量和输出

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# variables.tf
variable "instance_type" {
  description = "EC2 instance type"
  type        = string
  default     = "t2.micro"
}

variable "instance_count" {
  description = "Number of instances"
  type        = number
  default     = 2
}

# outputs.tf
output "instance_ips" {
  description = "Instance public IPs"
  value       = aws_instance.web[*].public_ip
}
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# terraform.tfvars
instance_type  = "t2.small"
instance_count = 3

四、模块

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

# modules/vpc/variables.tf
variable "cidr_block" {
  type = string
}

variable "name" {
  type = string
}

# modules/vpc/outputs.tf
output "vpc_id" {
  value = aws_vpc.this.id
}

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

五、状态管理

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# backend.tf
terraform {
  backend "s3" {
    bucket = "my-terraform-state"
    key    = "prod/terraform.tfstate"
    region = "us-west-2"
    
    dynamodb_table = "terraform-locks"
    encrypt        = true
  }
}

六、实战案例：Kubernetes集群

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# eks.tf
module "eks" {
  source  = "terraform-aws-modules/eks/aws"
  version = "18.0.0"
  
  cluster_name    = "my-cluster"
  cluster_version = "1.24"
  
  vpc_id     = module.vpc.vpc_id
  subnet_ids = module.vpc.private_subnets
  
  eks_managed_node_groups = {
    default = {
      min_size     = 1
      max_size     = 3
      desired_size = 2
      
      instance_types = ["t3.medium"]
    }
  }
}

总结

Terraform核心概念：

  1. 声明式：描述期望状态
  2. Provider：云平台接口
  3. 资源：基础设施组件
  4. 状态管理：记录资源状态
  5. 模块：代码复用

参考资料