参考:
基础架构即代码
基础架构即代码(IaC, Infrastructure as Code)，是通过代码（而非手动流程）来管理和置备基础架构（网络、虚拟机、负载均衡器和连接拓扑）的方法。
利用IaC，我们可以创建包含基础架构规范的配置文件，从而便于编辑和分发配置。此外，它还可确保每次置备的环境都完全相同。
版本控制是IaC的一个重要组成部分，就像其他任何软件源代码文件一样，配置文件也应该在源代码控制之下。
Terraform是一个基础设施即代码的工具，可让你安全有效地构建，更改和版本化基础设施。这包含了两个组件，低级别的如计算实例，存储和网络；高级别的DNS和SaaS功能。
Terraform通过其API在云平台或其它服务上创建和管理资源。供应商(provider)使得Terraform几乎可以使用任何平台和服务。可以在Terrafrom Registry上查询对应的供应商。如aws, gcp, azure, alicloud, tencentcloud等。
Terraform的工作流由三个阶段组成：
- Write: 定义资源。
- Plan: 基于现有基础架构和配置，描述是创建、更新或摧毁基础架构。
- Apply: 执行操作。
用例
- 多云部署
- 应用基础设施部署，扩展和监控工具
- 自助集群
- 政策合规性和管理
- Paas应用配置
- 软件定义的网络
- Kubernetes
- 并行环境
- 软件演示
快速开始
AWS示例
导入aws相关认证
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export AWS_ACCESS_KEY_ID="<YOUR_AWS_ACCESS_KEY_ID>"
export AWS_SECRET_ACCESS_KEY="<YOUR_AWS_SECRET_ACCESS_KEY>"
export AWS_DEFAULT_REGION="<YOUR_AWS_DEFAULT_REGION>"
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编写配置
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mkdir learn-terraform-aws-instance
cd learn-terraform-aws-instance
touch main.tf
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配置内容
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# terraform块包含Terraform设置
# 包含需要的provider
terraform {
required_providers {
aws = {
source = "hashicorp/aws"
version = "~> 3.27"
}
}
required_version = ">= 0.14.9"
}
# provider块配置特定的provider
provider "aws" {
profile = "default"
region = "us-west-2"
}
# resource块定义基础设施的组件
resource "aws_instance" "app_server" {
ami = "ami-830c94e3"
instance_type = "t2.micro"
tags = {
Name = "ExampleAppServerInstance"
}
}
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初始化目录
格式化和验证配置
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terraform fmt
terraform validate
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查看变更和创建基础设施
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terraform plan
terraform apply
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查看状态
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terraform show
terraform state list
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定义变量
创建variables.tf文件，定义变量。
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variable "instance_name" {
description = "value of the name tag for ec2 instance"
type = string
default = "ExampleAppServerInstance"
}
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使用变量
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resource "aws_instance" "app_server" {
ami = "ami-08d70e59c07c61a3a"
instance_type = "t2.micro"
tags = {
- Name = "ExampleAppServerInstance"
+ Name = var.instance_name
}
}
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也可以在命令上上使用-var "instance_name=YetAnotherName"来设置变量。
在输出中查询数据
编写output.tf
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output "instance_id" {
description = "ID of the EC2 instance"
value = aws_instance.app_server.id
}
output "instance_public_ip" {
description = "Public IP address of the EC2 instance"
value = aws_instance.app_server.public_ip
}
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查看输出内容
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terraform output
instance_id = "i-0bf954919ed765de1"
instance_public_ip = "54.186.202.254"
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Terraform使用HCL(Hashicorp Configuration Language)。
Terraform语言的语法由一些基础元素组成:
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resource "aws_vpc" "main" {
cidr_block = var.base_cidr_block
}
<BLOCK TYPE> "<BLOCK LABEL>" "<BLOCK LABEL>" {
# Block body
<IDENTIFIER> = <EXPRESSION> # Agrument
}
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示例:
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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)
}
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