tf-mod-aws-subnets

Module description

Use the tf-mod-aws-subnets Terraform module to provision dynamic private/public subnets with NAT instances or gateways.

Project: %!s() : [%!s()] | [%!s()]

Introduction

AWS resources deployed with this project includes:

• Dynamic subnets based on var.cidr_block input and number of Availability Zones in the region.
  • typically three private & public subnets are created.
• Deploys a number of private and public route tables as availability zones and associates the dynamically created subnets and appropriate NAT instances/gateways automattically
• (Recommended) - Deploys a number of NAT gateways based on the number of available zones and creates a route for each respective private subnet to route through to the internet
• (Optional) - Deploys a number of NAT instances based on the number of available zones and creates a route for each respective private subnet to route through to the internet

Usage

The below values shown in the usage of this module are purely representative, please replace desired values as required.

  module "tf-mod-aws-subnets" {
    source                  = "git::https://github.com:Callumccr/tf-mod-aws-subnets.git?ref=master"
    enabled                 = true
    aws_region              = "eu-west-1"
    vpc_id                  = "vpc-020cb3f232eeb11db7"
    igw_id                  = "igw-022c7022fadvd4f2c"
    cidr_block              = "10.0.0.0/16"
    availability_zones      = ["eu-west-1a", "eu-west-1b", "eu-west-1c"]
    nat_gateway_enabled     = true
    nat_instance_enabled    = false
    map_public_ip_on_launch = true
    tags                    = {
                              "ABC" = "XYZ"
                              }
  }

Quick Start

Examples

Simple and advanced examples of this project.

Advanced Example 1:

module "tf-mod-aws-vpc" {
  source         = "git::https://github.com:Callumccr/tf-mod-aws-vpc.git?ref=master"
  enabled        = true
  aws_account_id = "12345678910"
  aws_region     = "eu-west-1"
  cidr_block     = "10.0.0.0/16"
  tags           = {
                    "ABC" = "XYZ"
                    }
}

module "tf-mod-aws-subnets" {
  source                  = "git::https://github.com:Callumccr/tf-mod-aws-subnets.git?ref=master"
  enabled                 = true
  aws_region              = "eu-west-1"
  vpc_id                  = module.tf-mod-aws-vpc.vpc_id
  igw_id                  = module.tf-mod-aws-vpc.igw_id
  cidr_block              = module.tf-mod-aws-vpc.cidr_block
  availability_zones      = ["eu-west-1a", "eu-west-1b", "eu-west-1c"]
  nat_gateway_enabled     = true
  nat_instance_enabled    = false
  map_public_ip_on_launch = true
  tags                    = {
                            "ABC" = "XYZ"
                            }
}

Providers

Name	Version
aws	~> 2.0 >= 2.7.0

Inputs

Name	Description	Type	Default	Required
cidr_block	Base CIDR block which will be divided into subnet CIDR blocks (e.g. 10.0.0.0/16)	string	n/a	yes
igw_id	Internet Gateway ID the public route table will point to (e.g. igw-9c26a123)	string	n/a	yes
vpc_id	VPC ID where subnets will be created (e.g. vpc-aceb2723)	string	n/a	yes
attributes	(Optional) - Additional attributes (e.g. 1)	list(string)	[]	no
aws_account_id	The AWS account id of the provider being deployed to (e.g. 12345678). Autoloaded from account.tfvars	string	""	no
aws_assume_role_arn	(Optional) - ARN of the IAM role when optionally connecting to AWS via assumed role. Autoloaded from account.tfvars.	string	""	no
aws_assume_role_external_id	(Optional) - The external ID to use when making the AssumeRole call.	string	""	no
aws_assume_role_session_name	(Optional) - The session name to use when making the AssumeRole call.	string	""	no
aws_region	The AWS region (e.g. ap-southeast-2). Autoloaded from region.tfvars.	string	""	no
delimiter	(Optional) - Delimiter to be used between namespace, environment, stage, name and attributes	string	"-"	no
enabled	(Optional). A Switch that decides whether to create a terraform resource or run a provisioner. Default is true	bool	true	no
environment	(Optional) - Environment, e.g. 'dev', 'qa', 'staging', 'prod'	string	""	no
map_public_ip_on_launch	Instances launched into a public subnet should be assigned a public IP address	bool	true	no
max_subnet_count	Sets the maximum amount of subnets to deploy. 0 will deploy a subnet for every provided availablility zone (in availability_zones variable) within the region	number	0	no
name	(Optional) - Solution name, e.g. 'vault', 'consul', 'keycloak', 'k8s', or 'baseline'	string	""	no
namespace	(Optional) - Namespace, which could be your abbreviated product team, e.g. 'rci', 'mi', 'hp', or 'core'	string	""	no
nat_gateway_enabled	Flag to enable/disable NAT Gateways to allow servers in the private subnets to access the Internet	bool	true	no
nat_instance_enabled	Flag to enable/disable NAT Instances to allow servers in the private subnets to access the Internet	bool	false	no
nat_instance_type	NAT Instance type	string	"t3.micro"	no
private_network_acl_id	Network ACL ID that will be added to private subnets. If empty, a new ACL will be created	string	""	no
public_network_acl_id	Network ACL ID that will be added to public subnets. If empty, a new ACL will be created	string	""	no
subnet_type_tag_key	Key for subnet type tag to provide information about the type of subnets, e.g. cpco.io/subnet/type=private or cpco.io/subnet/type=public	string	"cpco.io/subnet/type"	no
subnet_type_tag_value_format	This is using the format interpolation symbols to allow the value of the subnet_type_tag_key to be modified.	string	"%s"	no
tags	(Optional) - Additional tags	map(string)	{}	no
vpc_default_route_table_id	Default route table for public subnets. If not set, will be created. (e.g. rtb-f4f0ce12)	string	""	no

Outputs

Name	Description
availability_zones	List of Availability Zones where subnets were created
nat_gateway_ids	IDs of the NAT Gateways created
private_route_table_ids	IDs of the created private route tables
private_subnet_cidrs	CIDR blocks of the created private subnets
private_subnet_ids	IDs of the created private subnets
public_route_table_ids	IDs of the created public route tables
public_subnet_cidrs	CIDR blocks of the created public subnets
public_subnet_ids	IDs of the created public subnets

Related Projects

You can find more Terraform Modules by vising the link.

Additionally, check out these other related, and maintained projects.

• %!s() - %!s()

References

For additional context, refer to some of these links.

• cloudposse/terraform-aws-dynamic-subnets - Unmodified upstream provided for this module

Help

Got a question? We got answers.

File a Github issue, or message us on Slack

Contributors

Callum Robertson

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