VPC 네트워크 구축 - 정답 및 해설

# 1. VPC 생성
aws ec2 create-vpc \
  --cidr-block 10.0.0.0/16 \
  --tag-specifications 'ResourceType=vpc,Tags=[{Key=Name,Value=ShopEasy-VPC}]' \
  --region ap-northeast-2

# VPC ID를 변수에 저장 (이후 명령어에서 활용)
VPC_ID=$(aws ec2 describe-vpcs \
  --filters "Name=tag:Name,Values=ShopEasy-VPC" \
  --query "Vpcs[0].VpcId" \
  --output text \
  --region ap-northeast-2)

echo "VPC ID: $VPC_ID"

# DNS 호스트 이름 활성화 (EC2 인스턴스에 DNS 이름 부여)
aws ec2 modify-vpc-attribute \
  --vpc-id $VPC_ID \
  --enable-dns-hostnames '{"Value":true}' \
  --region ap-northeast-2

# 퍼블릭 서브넷 A 생성
SUBNET_PUB_A=$(aws ec2 create-subnet \
  --vpc-id $VPC_ID \
  --cidr-block 10.0.1.0/24 \
  --availability-zone ap-northeast-2a \
  --tag-specifications 'ResourceType=subnet,Tags=[{Key=Name,Value=ShopEasy-Public-A}]' \
  --query 'Subnet.SubnetId' \
  --output text \
  --region ap-northeast-2)

echo "Public Subnet A: $SUBNET_PUB_A"

# 퍼블릭 서브넷 C 생성
SUBNET_PUB_C=$(aws ec2 create-subnet \
  --vpc-id $VPC_ID \
  --cidr-block 10.0.2.0/24 \
  --availability-zone ap-northeast-2c \
  --tag-specifications 'ResourceType=subnet,Tags=[{Key=Name,Value=ShopEasy-Public-C}]' \
  --query 'Subnet.SubnetId' \
  --output text \
  --region ap-northeast-2)

echo "Public Subnet C: $SUBNET_PUB_C"

# 퍼블릭 IP 자동 할당 활성화
aws ec2 modify-subnet-attribute \
  --subnet-id $SUBNET_PUB_A \
  --map-public-ip-on-launch \
  --region ap-northeast-2

aws ec2 modify-subnet-attribute \
  --subnet-id $SUBNET_PUB_C \
  --map-public-ip-on-launch \
  --region ap-northeast-2

# 프라이빗 서브넷 A 생성
SUBNET_PRIV_A=$(aws ec2 create-subnet \
  --vpc-id $VPC_ID \
  --cidr-block 10.0.100.0/24 \
  --availability-zone ap-northeast-2a \
  --tag-specifications 'ResourceType=subnet,Tags=[{Key=Name,Value=ShopEasy-Private-A}]' \
  --query 'Subnet.SubnetId' \
  --output text \
  --region ap-northeast-2)

echo "Private Subnet A: $SUBNET_PRIV_A"

# 프라이빗 서브넷 C 생성
SUBNET_PRIV_C=$(aws ec2 create-subnet \
  --vpc-id $VPC_ID \
  --cidr-block 10.0.101.0/24 \
  --availability-zone ap-northeast-2c \
  --tag-specifications 'ResourceType=subnet,Tags=[{Key=Name,Value=ShopEasy-Private-C}]' \
  --query 'Subnet.SubnetId' \
  --output text \
  --region ap-northeast-2)

echo "Private Subnet C: $SUBNET_PRIV_C"

# 인터넷 게이트웨이 생성
IGW_ID=$(aws ec2 create-internet-gateway \
  --tag-specifications 'ResourceType=internet-gateway,Tags=[{Key=Name,Value=ShopEasy-IGW}]' \
  --query 'InternetGateway.InternetGatewayId' \
  --output text \
  --region ap-northeast-2)

echo "IGW ID: $IGW_ID"

# VPC에 인터넷 게이트웨이 연결
aws ec2 attach-internet-gateway \
  --internet-gateway-id $IGW_ID \
  --vpc-id $VPC_ID \
  --region ap-northeast-2

echo "IGW $IGW_ID attached to VPC $VPC_ID"

# 탄력적 IP 할당
EIP_ALLOC=$(aws ec2 allocate-address \
  --domain vpc \
  --tag-specifications 'ResourceType=elastic-ip,Tags=[{Key=Name,Value=ShopEasy-NAT-EIP}]' \
  --query 'AllocationId' \
  --output text \
  --region ap-northeast-2)

echo "Elastic IP Allocation ID: $EIP_ALLOC"

# NAT Gateway 생성 (퍼블릭 서브넷 A에 배치)
NAT_GW_ID=$(aws ec2 create-nat-gateway \
  --subnet-id $SUBNET_PUB_A \
  --allocation-id $EIP_ALLOC \
  --tag-specifications 'ResourceType=natgateway,Tags=[{Key=Name,Value=ShopEasy-NAT}]' \
  --query 'NatGateway.NatGatewayId' \
  --output text \
  --region ap-northeast-2)

echo "NAT Gateway ID: $NAT_GW_ID"

# NAT Gateway가 Available 상태가 될 때까지 대기
aws ec2 wait nat-gateway-available \
  --nat-gateway-ids $NAT_GW_ID \
  --region ap-northeast-2

echo "NAT Gateway is now available!"

# 퍼블릭 라우트 테이블 생성
PUB_RT_ID=$(aws ec2 create-route-table \
  --vpc-id $VPC_ID \
  --tag-specifications 'ResourceType=route-table,Tags=[{Key=Name,Value=ShopEasy-Public-RT}]' \
  --query 'RouteTable.RouteTableId' \
  --output text \
  --region ap-northeast-2)

echo "Public Route Table ID: $PUB_RT_ID"

# 인터넷 게이트웨이로의 라우트 추가
aws ec2 create-route \
  --route-table-id $PUB_RT_ID \
  --destination-cidr-block 0.0.0.0/0 \
  --gateway-id $IGW_ID \
  --region ap-northeast-2

# 퍼블릭 서브넷 2개를 라우트 테이블에 연결
aws ec2 associate-route-table \
  --route-table-id $PUB_RT_ID \
  --subnet-id $SUBNET_PUB_A \
  --region ap-northeast-2

aws ec2 associate-route-table \
  --route-table-id $PUB_RT_ID \
  --subnet-id $SUBNET_PUB_C \
  --region ap-northeast-2

echo "Public subnets associated with Public RT"

# 프라이빗 라우트 테이블 생성
PRIV_RT_ID=$(aws ec2 create-route-table \
  --vpc-id $VPC_ID \
  --tag-specifications 'ResourceType=route-table,Tags=[{Key=Name,Value=ShopEasy-Private-RT}]' \
  --query 'RouteTable.RouteTableId' \
  --output text \
  --region ap-northeast-2)

echo "Private Route Table ID: $PRIV_RT_ID"

# NAT Gateway로의 라우트 추가
aws ec2 create-route \
  --route-table-id $PRIV_RT_ID \
  --destination-cidr-block 0.0.0.0/0 \
  --nat-gateway-id $NAT_GW_ID \
  --region ap-northeast-2

# 프라이빗 서브넷 2개를 라우트 테이블에 연결
aws ec2 associate-route-table \
  --route-table-id $PRIV_RT_ID \
  --subnet-id $SUBNET_PRIV_A \
  --region ap-northeast-2

aws ec2 associate-route-table \
  --route-table-id $PRIV_RT_ID \
  --subnet-id $SUBNET_PRIV_C \
  --region ap-northeast-2

echo "Private subnets associated with Private RT"