jyotti / terraform-aws-vpc

AWS VPC Terraform module

About VPC

Subnet

• public - Internet gateway
• private - NAT Gateway
• intra - None(Intranet)

Usage

Single Public Subnet

Reference - https://docs.aws.amazon.com/vpc/latest/userguide/VPC_Scenario1.html

• Subnet - public
• NAT Gateway : no

module "vpc" {
  source             = "github.com/jyotti/terraform-aws-vpc?ref=v0.1.1"
  name               = "simple"
  cidr_block         = "10.0.0.0/16"
  public_subnets     = ["10.0.32.0/20", "10.0.96.0/20", "10.0.160.0/20"]
  availability_zones = ["us-east-1a", "us-east-1b", "us-east-1c"]

  tags = {
    Stage = "dev"
  }
}

Public and Private Subnets (NAT)

Reference - https://docs.aws.amazon.com/vpc/latest/userguide/VPC_Scenario2.html

• Subnet - public, private
• NAT Gateway : yes

module "vpc" {
  source             = "github.com/jyotti/terraform-aws-vpc?ref=v0.1.1"
  name               = "public-and-private-subnets"
  cidr_block         = "10.0.0.0/16"
  public_subnets     = ["10.0.32.0/20", "10.0.96.0/20", "10.0.160.0/20"]
  private_subnets    = ["10.0.0.0/19", "10.0.64.0/19", "10.0.128.0/19"]
  availability_zones = ["us-east-1a", "us-east-1b", "us-east-1c"]

  enable_nat_gateway = true
  single_nat_gateway = true

  tags = {
    Stage = "dev"
  }
}

Example CIDR

I refer to the explanation of Practical VPC Design.

10.0.0.0/16
    10.0.0.0/18 - AZ1
      10.0.0.0/19 - private
      10.0.32.0/19
        10.0.32.0/20 - public
        10.0.48.0/20
          10.0.48.0/21 - intra
          10.0.56.0/21 - (spare)
    10.0.64.0/18 - AZ2
      10.0.64.0/19 - private
      10.0.96.0/19
        10.0.96.0/20  - public
        10.0.112.0/20
          10.0.112.0/21 - intra
          10.0.120.0/21 - (spare)
    10.0.128.0/18 - AZ3
      10.0.128.0/19 - private
      10.0.160.0/19
        10.0.160.0/20 - public
        10.0.176.0/20
          10.0.176.0/21 - intra
          10.0.184.0/21 - (spare)
    10.0.192.0/18 - (spare)

Inputs

Name	Description	Type	Default	Required
availability_zones	A list of availability zones in the region	list	<list>	no
cidr_block	The CIDR block for the VPC	string	10.0.0.0/16	no
enable_dynamodb_endpoint	Should be true if you want to provision a DynamoDB endpoint to the VPC	string	false	no
enable_nat_gateway	Should be true if you want to provision NAT Gateways for each of your private networks	string	false	no
enable_s3_endpoint	Should be true if you want to provision an S3 endpoint to the VPC	string	false	no
intra_subnet_suffix	Suffix to append to intra subnets name	string	intra	no
intra_subnet_tags	Additional tags for the intra subnets	map	<map>	no
intra_subnets	List of CIDR block for intra subnet	list	<list>	no
map_public_ip_on_launch	Should be false if you do not want to auto-assign public IP on launch	string	true	no
name	Name to be used on all the resources as identifier	string	``	no
private_subnet_suffix	Suffix to append to private subnets name	string	private	no
private_subnet_tags	Additional tags for the private subnets	map	<map>	no
private_subnets	List of CIDR block for private subnet	list	<list>	no
public_subnet_suffix	Suffix to append to public subnets name	string	public	no
public_subnet_tags	Additional tags for the public subnets	map	<map>	no
public_subnets	List of CIDR block for public subnet	list	<list>	no
single_nat_gateway	Should be true if you want to provision a single shared NAT Gateway across all of your private networks	string	false	no
tags	A map of tags to add to all resources	map	<map>	no

Outputs

Name	Description
db_subnet_group	The db subnet group name
default_route_table_id	The ID of the default route table
default_security_group_id	The ID of the security group created by default on VPC creation
elasticache_subnet_group	The ElastiCache Subnet group ID
intra_route_table_ids	List of IDs of intra route tables
intra_subnet_ids	List of IDs of the intra subnet
private_route_table_ids	List of IDs of private route tables
private_subnet_ids	List of IDs of the private subnet
public_route_table_ids	List of IDs of public route tables
public_subnet_ids	List of IDs of the public subnet
redshift_subnet_group	The Redshift Subnet group ID
vpc_cidr_block	The CIDR block of the VPC
vpc_id	The ID of the VPC