Terraform AWS Base Networking
A Terraform module for building a base network in AWS.
The network consists of:
- Public and private subnets for each supplied availability zone
- A NAT gateway for each supplied availability zone for outbound Internet connectivity
- Routes from the public subnets to the Internet gateway
- Routes from the private subnets to the NAT
- Standard tags for all resources
Usage
To use the module, include something like the following in your terraform configuration:
module "base-network" {
source = "infrablocks/base-networking/aws"
version = "4.0.0"
vpc_cidr = "10.0.0.0/16"
region = "eu-west-2"
availability_zones = ["eu-west-2a", "eu-west-2b"]
component = "important-component"
deployment_identifier = "production"
private_zone_id = "Z3CVA9QD5NHSW3"
}
See the Terraform registry entry for more details.
Inputs
| Name | Description | Default | Required |
|---|---|---|---|
| vpc_cidr | The CIDR to use for the VPC | - | yes |
| region | The region into which to deploy the VPC | - | yes |
| availability_zones | The availability zones for which to add subnets | - | yes |
| public_subnets_offset | The number of /24s to offset the public subnets in the VPC CIDR | 0 | yes |
| private_subnets_offset | The number of /24s to offset the private subnets in the VPC CIDR | 0 | yes |
| component | The component this network will contain | - | yes |
| deployment_identifier | An identifier for this instantiation | - | yes |
| dependencies | The components depended on by this component | - | no |
| include_route53_zone_association | Whether or not to associate VPC with the private Route 53 zone ("yes" or "no") | "yes" | no |
| private_zone_id | The ID of the private Route 53 zone | - | if include_route53_zone_association is "yes" |
| include_nat_gateways | Whether or not to deploy NAT gateways for outbound Internet connectivity ("yes" or "no") | "yes" | yes |
Outputs
| Name | Description |
|---|---|
| vpc_id | The ID of the created VPC |
| vpc_cidr | The CIDR of the created VPC |
| availability_zones | The availability zones in which subnets were created |
| number_of_availability_zones | The number of populated availability zones available |
| public_subnet_ids | The IDs of the public subnets |
| public_subnet_cidrs | The CIDRs of the public subnets |
| public_route_table_ids | The IDs of the public route tables |
| private_subnet_ids | The IDs of the private subnets |
| private_subnet_cidrs | The CIDRs of the private subnets |
| private_route_table_ids | The IDs of the private route tables |
| nat_public_ips | The EIPs attached to the NAT gateways |
Compatibility
This module is compatible with Terraform versions greater than or equal to Terraform 1.0.
Required Permissions
- ec2:DescribeVpcs
- ec2:DescribeAddresses
- ec2:DescribeVpcAttribute
- ec2:DescribeVpcClassicLink
- ec2:DescribeVpcClassicLinkDnsSupport
- ec2:DescribeRouteTables
- ec2:DescribeSecurityGroups
- ec2:DescribeNetworkAcls
- ec2:DescribeSubnets
- ec2:DescribeInternetGateways
- ec2:DescribeNatGateways
- ec2:ModifyVpcAttribute
- ec2:AllocateAddress
- ec2:ReleaseAddress
- ec2:AssociateRouteTable
- ec2:DisassociateRouteTable
- ec2:AttachInternetGateway
- ec2:DetachInternetGateway
- ec2:DeleteInternetGateway
- ec2:CreateRoute
- ec2:CreateNatGateway
- ec2:CreateVpc
- ec2:CreateTags
- ec2:CreateSubnet
- ec2:CreateRouteTable
- ec2:CreateInternetGateway
- ec2:DeleteRoute
- ec2:DeleteRouteTable
- ec2:DeleteSubnet
- ec2:DeleteNatGateway
- ec2:DeleteVpc
- s3:ListBucket
- s3:GetObject
- s3:GetObjectTagging
- s3:DeleteObject
- route53:AssociateVPCWithHostedZone
- route53:DisassociateVPCFromHostedZone
- route53:GetChange
- route53:GetHostedZone
Development
Machine Requirements
In order for the build to run correctly, a few tools will need to be installed on your development machine:
- Ruby (2.3.1)
- Bundler
- git
- git-crypt
- gnupg
- direnv
Mac OS X Setup
Installing the required tools is best managed by homebrew.
To install homebrew:
ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
Then, to install the required tools:
# ruby
brew install rbenv
brew install ruby-build
echo 'eval "$(rbenv init - bash)"' >> ~/.bash_profile
echo 'eval "$(rbenv init - zsh)"' >> ~/.zshrc
eval "$(rbenv init -)"
rbenv install 2.3.1
rbenv rehash
rbenv local 2.3.1
gem install bundler
# git, git-crypt, gnupg
brew install git
brew install git-crypt
brew install gnupg
# direnv
brew install direnv
echo "$(direnv hook bash)" >> ~/.bash_profile
echo "$(direnv hook zsh)" >> ~/.zshrc
eval "$(direnv hook $SHELL)"
direnv allow <repository-directory>
Running the build
To provision module infrastructure, run tests and then destroy that infrastructure, execute:
./goTo provision the module prerequisites:
./go deployment:prerequisites:provision[<deployment_identifier>]To provision the module contents:
./go deployment:harness:provision[<deployment_identifier>]To destroy the module contents:
./go deployment:harness:destroy[<deployment_identifier>]To destroy the module prerequisites:
./go deployment:prerequisites:destroy[<deployment_identifier>]Common Tasks
Generating an SSH key pair
To generate an SSH key pair:
ssh-keygen -t rsa -b 4096 -C [email protected] -N '' -f config/secrets/keys/bastion/ssh
Managing CircleCI keys
To encrypt a GPG key for use by CircleCI:
openssl aes-256-cbc \
-e \
-md sha1 \
-in ./config/secrets/ci/gpg.private \
-out ./.circleci/gpg.private.enc \
-k "<passphrase>"To check decryption is working correctly:
openssl aes-256-cbc \
-d \
-md sha1 \
-in ./.circleci/gpg.private.enc \
-k "<passphrase>"Contributing
Bug reports and pull requests are welcome on GitHub at https://github.com/infrablocks/terraform-aws-base-networking. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.
License
The library is available as open source under the terms of the MIT License.