SRE文档

深浅模式

1. 什么是HCL语言✅ ​

HCL（HashiCorp Configuration Language）是一种专门为构建结构化配置格式而设计的语法和API。 他由HashiCorp公司设计。

  • HCL是一个用于创建结构化配置语言的工具包，主要针对DevOps工具、服务器等。
  • HCL既有一种原生语法，旨在让人类愉快地阅读和编写，也有一种基于json的变体，更容易让机器生成和解析。
  • HCL包含一个表达式语法，允许基本的内联计算，并且在调用应用程序的支持下，可以使用变量和函数来进行更动态的配置语言。

2. Terraform语言✅ ​

Terraform语言的主要目的是声明资源，这些资源表示基础设施对象。所有其他语言特性的存在只是为了使资源的定义更加灵活和方便。

Terraform配置是一个用Terraform语言编写的完整文档，它告诉Terraform如何管理给定的基础设施集合。

一个配置可以由多个文件和目录组成。

2.1 语法 ​

https://developer.hashicorp.com/terraform/language/syntax

配置语法 ​

  • Terraform 的配置文件都是以 .tf 为后缀
  • Terraform 支持两种模式 HCL、JSON
yaml
<BLOCK TYPE> "<BLOCK LABEL>" "<BLOCK LABEL>" "..." {
  # Block body
  <IDENTIFIER> = <EXPRESSION> # Argument
}

或称

<block type> "<RESOURCE TYPE>" "<LOCAL NAME/LABEL>"{
  # Block body
  <IDENTIFIER> = <EXPRESSION> # Argument
}

块类型 "块标签1/资源类型" "块标签2/本地名称/本地标签" {
  # 块主体
  参数 = 表达式 
	参数 = 表达式 
  ...
}
<BLOCK TYPE> "<BLOCK LABEL>" "<BLOCK LABEL>" "..." {
  # Block body
  <IDENTIFIER> = <EXPRESSION> # Argument
}

或称

<block type> "<RESOURCE TYPE>" "<LOCAL NAME/LABEL>"{
  # Block body
  <IDENTIFIER> = <EXPRESSION> # Argument
}

块类型 "块标签1/资源类型" "块标签2/本地名称/本地标签" {
  # 块主体
  参数 = 表达式 
	参数 = 表达式 
  ...
}

block（块）是其他内容的容器，通常表示某种对象的配置，如resource。block具有块类型，可以有零个或多个标签，并且具有包含任意数量的参数和嵌套块的主体。Terraform的大部分功能都由配置文件中的顶级块控制。

官方案例

yaml
terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 1.0.4"
    }
  }
}

variable "aws_region" {}

variable "base_cidr_block" {
  description = "A /16 CIDR range definition, such as 10.1.0.0/16, that the VPC will use"
  default = "10.1.0.0/16"
}

variable "availability_zones" {
  description = "A list of availability zones in which to create subnets"
  type = list(string)
}

provider "aws" {
  region = var.aws_region
}

resource "aws_vpc" "main" {
  # Referencing the base_cidr_block variable allows the network address
  # to be changed without modifying the configuration.
  cidr_block = var.base_cidr_block
}

resource "aws_subnet" "az" {
  # Create one subnet for each given availability zone.
  count = length(var.availability_zones)

  # For each subnet, use one of the specified availability zones.
  availability_zone = var.availability_zones[count.index]

  # By referencing the aws_vpc.main object, Terraform knows that the subnet
  # must be created only after the VPC is created.
  vpc_id = aws_vpc.main.id

  # Built-in functions and operators can be used for simple transformations of
  # values, such as computing a subnet address. Here we create a /20 prefix for
  # each subnet, using consecutive addresses for each availability zone,
  # such as 10.1.16.0/20 .
  cidr_block = cidrsubnet(aws_vpc.main.cidr_block, 4, count.index+1)
}
terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 1.0.4"
    }
  }
}

variable "aws_region" {}

variable "base_cidr_block" {
  description = "A /16 CIDR range definition, such as 10.1.0.0/16, that the VPC will use"
  default = "10.1.0.0/16"
}

variable "availability_zones" {
  description = "A list of availability zones in which to create subnets"
  type = list(string)
}

provider "aws" {
  region = var.aws_region
}

resource "aws_vpc" "main" {
  # Referencing the base_cidr_block variable allows the network address
  # to be changed without modifying the configuration.
  cidr_block = var.base_cidr_block
}

resource "aws_subnet" "az" {
  # Create one subnet for each given availability zone.
  count = length(var.availability_zones)

  # For each subnet, use one of the specified availability zones.
  availability_zone = var.availability_zones[count.index]

  # By referencing the aws_vpc.main object, Terraform knows that the subnet
  # must be created only after the VPC is created.
  vpc_id = aws_vpc.main.id

  # Built-in functions and operators can be used for simple transformations of
  # values, such as computing a subnet address. Here we create a /20 prefix for
  # each subnet, using consecutive addresses for each availability zone,
  # such as 10.1.16.0/20 .
  cidr_block = cidrsubnet(aws_vpc.main.cidr_block, 4, count.index+1)
}