Terraform module - AWS basic network

A terraform module that deploys a VPC and two types of subnets.

Usage

It is the user's responsibility to calculate the CIDRs for the VPC and subnets so that they are sensible.

The subnet types are designated public and private.

• The "public" subnets allow for resources in it to be reachable from the internet.
• The "private" subnets do not allow incoming connections from the internet, but still allow outbound connections from the resources in it.

Notes:

• The input variables that define the subnets to be created - public_subnet_cidrs and private_subnet_cidrs are actually maps and not lists of CIDRs as one might expect. The keys of the map define the CIDRs of the subnets while the values define the availability zone in which the subnet will be created. These values are of type number and they are used as an index to select an availability zone form the list of zones for the current AWS region.

• To allow connectivity for the private subnets an aws_nat_gateway is created in the first public subnet in the list. Therefore the public subnet list can never be with 0 elements. If the private subnets list is empty the aws_nat_gateway and its associated resources will not be crated as well.

Inputs

Name	Description	Type	Default	Required
common_tags	A mapping of tags to be applied to the created resources.	map(string)	n/a	yes
name_prefix	n/a	string	""	no
private_subnet_cidrs	List of objects reprisenting the private subnets CIDRs and their availability zones. The az_index property is used as an index to retireve a zone from the list of the availability zones for the current AWS region.	list(object({ cidr = string az_index = number }))	[]	no
private_subnet_tags	A mapping of tags to be applied to the private subnets.	map(string)	{}	no
public_subnet_cidrs	List of objects reprisenting the public subnets CIDRs and their availability zones. The az_index property is used as an index to retireve a zone from the list of the availability zones for the current AWS region.	list(object({ cidr = string az_index = number }))	n/a	yes
public_subnet_tags	A mapping of tags to be applied to the public subnets.	map(string)	{}	no
vpc_cidr_block	CIDR block to assign to the VPC	string	n/a	yes

Outputs

Name	Description
main_route_table_id	The id of the VPC default routing table. It is not used by any subnets.
nat_gateway_public_ip	The public IP of the NAT gateway.
private_route_table_id	The id of the privagte routing table. Used by the private subnets.
private_subnet_ids	Ids of the private subents.
private_subnets	A mapping of input private subnet CIDR and created subnet.
public_route_table_id	The id of the public subnets route table.
public_subnet_ids	Ids of the 'public' subents.
public_subnets	A mapping of input public subnet CIDR and created subnet.
vpc_id	The id of the VPC which was created.

Requirements

Name	Version
terraform	>= 0.12.26
aws	>= 3.0

Resources

Name	Type
aws_eip.nat_gw	resource
aws_internet_gateway.gw	resource
aws_nat_gateway.gw	resource
aws_route.default_private	resource
aws_route.default_public	resource
aws_route_table.private	resource
aws_route_table.public	resource
aws_route_table_association.private	resource
aws_route_table_association.public	resource
aws_subnet.private	resource
aws_subnet.public	resource
aws_vpc.main	resource
aws_availability_zones.azs	data source

Documentation

Generated with terraform-docs.

terraform-docs markdown table ./terraform -c .terraform-docs.yaml > README.md