[AWS 기본] Terraform으로 AWS 3 Tier 구성하기

1. Network 구성

---

RESOURCE

Resource	AZ	ip	tags	tags
1. VPC	-	1		yuran-test-vpc
2. IGW	-	1		yuran-test-igw
3. Subnet	a	1	public	yuran-test-PublicSubnet-ap-northeast-2a
3. Subnet	c	1	public	yuran-test-PublicSubnet-ap-northeast-2c
3. Subnet	a	1	WEB	yuran-test-PrivateSubnet-0-ap-northeast-2a
3. Subnet	c	1	WEB	yuran-test-PrivateSubnet-1-ap-northeast-2c
3. Subnet	a	1	WAS	yuran-test-PrivateSubnet-2-ap-northeast-2a
3. Subnet	c	1	WAS	yuran-test-PrivateSubnet-3-ap-northeast-2a
3. Subnet	a	1	DB	yuran-test-DBSubnet-ap-northeast-2a
3. Subnet	c	1	DB	yuran-test-DBSubnet-ap-northeast-2c
4. Nat Gateway	-	1	public Subnet에	natgw

Route Table

1.1 vpc

• vpc.tf

    provider "aws" {
      region  = var.region
    }
      
    #1. vpc 
    resource "aws_vpc" "yuran-test-vpc" {
      cidr_block       = var.vpc_cidr
      enable_dns_support   = true
      enable_dns_hostnames = true
      
      tags = {
        Name = format("%s-VPC", var.name)
      }
    }
  

  1.2 igw

• igw.tf

    #2. igw
    resource "aws_internet_gateway" "yuran-test-igw" {
      vpc_id = aws_vpc.yuran-test-vpc.id
      
      tags = {
        Name = format("%s-igw", var.name)
      }
    }
  

  1.3 subnets

• subnets.tf

    #3. subnets
      
    resource "aws_subnet" "public" {
      count                   = var.Desired_public_subnets
      vpc_id                  = aws_vpc.yuran-test-vpc.id
      cidr_block              = cidrsubnet(var.vpc_cidr, 8, count.index)
      map_public_ip_on_launch = true
      availability_zone       = element(var.aws_az_des, count.index)
      tags = {
        Name = format("%s-PublicSubnet-%s", var.name, element(var.aws_az_des, count.index))
      }
    }
    resource "aws_subnet" "private" {
      count                   = var.Desired_private_subnets
      vpc_id                  = aws_vpc.yuran-test-vpc.id
      cidr_block              = cidrsubnet(var.vpc_cidr, 8, count.index + 2)
      # map_public_ip_on_launch = true
      availability_zone       = element(var.aws_az_des, count.index)
      tags = {
        Name = format("%s-PrivateSubnet-%s-%s", var.name, count.index, element(var.aws_az_des, count.index))
      }
    }
      
    resource "aws_subnet" "DB" {
      count                   = var.Desired_DB_subnets
      vpc_id                  = aws_vpc.yuran-test-vpc.id
      cidr_block              = cidrsubnet(var.vpc_cidr, 8, count.index + 6)
      # map_public_ip_on_launch = true
      availability_zone       = element(var.aws_az_des, count.index)
      tags = {
        Name = format("%s-DBSubnet-%s", var.name, element(var.aws_az_des, count.index))
      }
    }
  

  1.4 natgw

• natgw.tf

      
    #4. Elastic IP for NAT Gateway
    resource "aws_eip" "yuran-nat-eip" {
      domain = "vpc"
    }
      
    resource "aws_nat_gateway" "natgw" {
      allocation_id = aws_eip.yuran-nat-eip.id
      subnet_id     = element(aws_subnet.public.*.id, 0)
      tags = {
          Name = format("%s-EIP", var.name)
          }
        }
  

1.5 route table

• routable.tf

    ###route table
      
    ##2.1 route table for public subnets (igw)
      
    resource "aws_route_table" "public-rtb" {
      vpc_id = aws_vpc.yuran-test-vpc.id
      
      tags = {
          Name = format("%s-public-Route-Table", var.name)
        }
    }
      
    # create route for the private route table and attatch a nat gateway to it
    resource "aws_route" "public-rtb-route" {
      route_table_id         = aws_route_table.public-rtb.id
      destination_cidr_block = "0.0.0.0/0"
      gateway_id             = aws_internet_gateway.yuran-test-igw.id
    }
      
    # associate all private subnets to the private route table
    resource "aws_route_table_association" "public-subnets-assoc" {
      count          = length(aws_subnet.public[*].id)
      subnet_id      = element(aws_subnet.public[*].id, count.index)
      route_table_id = aws_route_table.public-rtb.id
    }
      
    ##4.1 route table for private subnets (natgw)
      
    resource "aws_route_table" "private-rtb" {
      vpc_id = aws_vpc.yuran-test-vpc.id
      
      tags = {
          Name = format("%s-Private-Route-Table", var.name)
        }
    }
      
    # create route for the private route table and attatch a nat gateway to it
    resource "aws_route" "private-rtb-route" {
      route_table_id         = aws_route_table.private-rtb.id
      destination_cidr_block = "0.0.0.0/0"
      gateway_id             = aws_nat_gateway.natgw.id
    }
      
    # associate all private subnets to the private route table
    resource "aws_route_table_association" "private-subnets-assoc" {
      count          = length(aws_subnet.private[*].id) + length(aws_subnet.DB[*].id)
      subnet_id      = element(concat(aws_subnet.private[*].id, aws_subnet.DB[*].id), count.index)
      route_table_id = aws_route_table.private-rtb.id
    }
  

• 참고 문법