お疲れ様です。福島です。

今回はネットワーク周りの下記の構築を行っていきます。

・VPC
・サブネット
・ルートテーブル
・IGW

■構成図

■VPC

resource "aws_vpc" "vpc" {
  cidr_block                       = "192.168.0.0/20"
  instance_tenancy                 = "default"
  enable_dns_support               = true
  enable_dns_hostnames             = true
  assign_generated_ipv6_cidr_block = false

  tags = {
    Name    = "kai.fukushima-${var.project}-${var.enviroment}-vpc"
    project = var.project
    Env     = var.enviroment
  }
}

■Subnet

resource "aws_subnet" "kaifukushima-public-subnet-1a" {
  vpc_id                  = aws_vpc.vpc.id
  availability_zone       = "ap-northeast-1a"
  cidr_block              = "192.168.1.0/24"
  map_public_ip_on_launch = true

  tags = {
    Name    = "kaifukushima${var.project}-${var.enviroment}-public-subnet-1a"
    Project = var.project
    Env     = var.enviroment
    Type    = "public"
  }
}

resource "aws_subnet" "kaifukushima-public-subnet-1c" {
  vpc_id                  = aws_vpc.vpc.id
  availability_zone       = "ap-northeast-1c"
  cidr_block              = "192.168.2.0/24"
  map_public_ip_on_launch = true

  tags = {
    Name    = "kaifukushima${var.project}-${var.enviroment}-public-subnet-1c"
    Project = var.project
    Env     = var.enviroment
    Type    = "public"
  }
}

resource "aws_subnet" "kaifukushima-private-subnet-1a" {
  vpc_id                  = aws_vpc.vpc.id
  availability_zone       = "ap-northeast-1a"
  cidr_block              = "192.168.3.0/24"
  map_public_ip_on_launch = false

  tags = {
    Name    = "kaifukushima${var.project}-${var.enviroment}-private-subnet-1a"
    Project = var.project
    Env     = var.enviroment
    Type    = "private"
  }
}

resource "aws_subnet" "kaifukushima-private-subnet-1c" {
  vpc_id                  = aws_vpc.vpc.id
  availability_zone       = "ap-northeast-1c"
  cidr_block              = "192.168.4.0/24"
  map_public_ip_on_launch = false

  tags = {
    Name    = "kaifukushima${var.project}-${var.enviroment}-private-subnet-1c"
    Project = var.project
    Env     = var.enviroment
    Type    = "private"
  }
}

■Route table

resource "aws_route_table" "kaifukushima-public-rt" {
  vpc_id = aws_vpc.vpc.id

  tags = {
    Name    = "kaifukushima${var.project}-${var.enviroment}-public-rt"
    Project = var.project
    Env     = var.enviroment
    Type    = "public"
  }
}

resource "aws_route_table_association" "public_rt_1a" {
  route_table_id = aws_route_table.kaifukushima-public-rt.id
  subnet_id      = aws_subnet.kaifukushima-public-subnet-1a.id
}

resource "aws_route_table_association" "public_rt_1c" {
  route_table_id = aws_route_table.kaifukushima-public-rt.id
  subnet_id      = aws_subnet.kaifukushima-public-subnet-1c.id
}

resource "aws_route_table" "kaifukushima-private-rt" {
  vpc_id = aws_vpc.vpc.id

  tags = {
    Name    = "kaifukushima${var.project}-${var.enviroment}-private-rt"
    Project = var.project
    Env     = var.enviroment
    Type    = "private"
  }
}

resource "aws_route_table_association" "private_rt_1a" {
  route_table_id = aws_route_table.kaifukushima-private-rt.id
  subnet_id      = aws_subnet.kaifukushima-private-subnet-1a.id
}

resource "aws_route_table_association" "private_rt_1c" {
  route_table_id = aws_route_table.kaifukushima-private-rt.id
  subnet_id      = aws_subnet.kaifukushima-private-subnet-1c.id
}

■Internet Gateway

resource "aws_internet_gateway" "igw" {
  vpc_id = aws_vpc.vpc.id

  tags = {
    Name    = "kaifukushima-${var.project}-${var.enviroment}-igw"
    Project = var.project
    Env     = var.enviroment
  }
}

resource "aws_route" "public_rt_igw_r" {
  route_table_id         = aws_route_table.kaifukushima-public-rt.id
  destination_cidr_block = "0.0.0.0/0"
  gateway_id             = aws_internet_gateway.igw.id
}

■まとめ

今回作成したネットワーク周りはコンソール上でも
何度も作成しているので、コードを書きながらどこの部分の事か
理解しながら書けました！

構築量が増えた来た際には
Terraformは非常に便利だと思いますが
何を書いているか分からなくなった際は
コンソールで構築を行い構造理解をする事が大事ですね。