Network Hub Account with Terraform

This repository demonstrates a scalable, segregated, secured AWS network for multi-account organizations. Using Transit Gateway to separate production, non-production and shared services traffic, it deploys an advanced AWS networking pattern using centralized ingress and egress behind Network Firewall, centralizes private VPC endpoints to share across all VPCs, and manages IP address allocation using Amazon VPC IPAM.

Perfect for a central networking hub account, potentially alongside Account Factory for Terraform
Solution itself can be deployed into nonprod, test and production deployments for safe iteration and testing.
Written using clean, composable modules: the solution is easily extended and customised.

Spoke VPCs for organization members can be created using the provided sister example in this repo.

The following resources will be deployed by this example:

VPC Transit Gateway
VPC Endpoints
AWS Network Firewall
Route 53 Resolver
Amazon VPC IP Address Manager

The resources deployed and the architectural pattern they follow are provided for demonstration and testing purposes but are based on and inspired by AWS best practice and articles.

Overview

Diagrams

Solution Diagram

Transit Gateway

VPC Endpoints

Network Firewall

Route 53 Resolver

References

Prerequisites

Minimal tooling is required for this solution. However, there are hard requirements around AWS configuration.

Tooling

Terraform ~> 1.1
- AWS provider >= 4.4.0
AWS CLI
Git CLI

AWS account configuration

AWS Organization
Centralised network account
IAM role with required permissions
RAM sharing enabled for the Organisation

aws ram enable-sharing-with-aws-organization

Troubleshooting tip

If you experience any issue with the RAM share disable and re-enable RAM.

aws organizations disable-aws-service-access --service-principal ram.amazonaws.com

IPAM delegated from the master account to the Centralised network account

aws ec2 enable-ipam-organization-admin-account \
    --delegated-admin-account-id <Network-Account-ID>

Customisation

If you do not define a remote backend Terraform will use the local directory to store the backend files including tfstate. Examples of how to customise the Terraform backend are included but commented out. Usual caveats around safe storage of Terraform state must be considered.

Example GitLab HTTP backend for use with GitLab CI.

Variables

Type	Variable Name	Description	Notes
Global variables	environment	Environment to deploy into.	Accepted values * dev, test, preprod, prod
	aws_region	Region to deploy in.
	vpc_endpoints	List of centralised VPC endpoints to be deployed
Environment specific variables	ipam_cidr	CIDR to be allocated to the IP Address Manager
	tgw_route_tables	Transit Gateway Router Tables to create
	root_domain	Root DNS domain to create private hosted zone and resolver rules

Input Variable - config.auto.tfvars

aws_region    = "eu-west-2"
vpc_endpoints = ["ec2", "rds", "sqs", "sns", "ssm", "logs", "ssmmessages", "ec2messages", "autoscaling", "ecs", "athena"]

env_config = {
  dev = {
    ipam_cidr        = "10.0.0.0/10"
    tgw_route_tables = ["prod", "dev", "shared"]
    root_domain      = "network-dev.internal"
  }
  test = {
    ipam_cidr        = "10.64.0.0/10"
    tgw_route_tables = ["prod", "dev", "shared"]
    root_domain      = "network-test.internal"
  }
  preprod = {
    ipam_cidr        = "10.128.0.0/10"
    tgw_route_tables = ["prod", "dev", "shared"]
    root_domain      = "network-preprod.internal"
  }
  prod = {
    ipam_cidr        = "10.192.0.0/10"
    tgw_route_tables = ["prod", "dev", "shared"]
    root_domain      = "network-prod.internal"
  }
}

Quick Start

Deploy from client machine

When deploying from your local machine having configured the TF Backend in the code you need to ensure you have access to read and write to the backend - possible backends include HTTP, Consul, Postgres, Artifactory, S3 or S3 + DynamoDB. We initialise the Terraform, complete the validate and format. Review the plan and then apply.

terraform init
terraform validate
set environment for deployment
- export TF_VAR_environment="$ENV"
- Set-Item -Path env:TF_VAR_environment -Value "$ENV" (Possible $ENV values - dev, test, preprod, prod)
terraform plan
terraform apply or terraform apply --auto-approve

Tagging

Tags are added to all AWS resources through use of the tag configuration of the AWS Provider.

As not all AWS resources support default tags passed from the provider (EC2 Auto-Scaling Group + Launch Template) We pass the tags as a variable (Map(string) - these are defined in the root locals.tf file.

Example Tags - locals.tf

tags = {
  Product    = "Network_Automation"
  Owner      = "GitHub"
  Project_ID = "12345"
}

Clean Up

Remember to clean up after your work is complete. You can do that by doing terraform destroy.

Note that this command will delete all the resources previously created by Terraform.

Terraform Docs

Terraform Deployment

Requirements

Name	Version
terraform	~> 1.1
aws	>= 4.4.0

Providers

Name	Version
aws	4.5.0

Modules

Name	Source	Version
dns	./modules/dns	n/a
ipam	./modules/ipam	n/a
network_firewall_vpc	./modules/network_firewall_vpc	n/a
tgw	./modules/tgw	n/a
vpc_endpoints	./modules/vpc_endpoints	n/a

Resources

Name	Type
aws_iam_policy.central_network	resource
aws_iam_policy_attachment.central_network	resource
aws_iam_role.central_network	resource
aws_iam_role.flow_logs	resource
aws_iam_role_policy.flow_logs	resource
aws_kms_key.log_key	resource
aws_availability_zones.available	data source
aws_caller_identity.current	data source
aws_iam_policy_document.policy_kms_logs_document	data source
aws_organizations_organization.main	data source

Inputs

Name	Description	Type	Default	Required
aws_region	AWS region being deployed to	`string`	n/a	yes
env_config	Map of objects for per environment configuration	map(object({ ipam_cidr = string tgw_route_tables = list(string) root_domain = string }))	n/a	yes
environment	Deployment environment passed as argument or environment variable	`string`	n/a	yes
tags	Default tags to apply to all resources	`map(string)`	n/a	yes
vpc_endpoints	Which VPC endpoints to use	`list(string)`	n/a	yes

Outputs

No outputs.

TGW Module

Requirements

No requirements.

Providers

Name	Version
aws	n/a

Modules

No modules.

Resources

Name	Type
aws_ec2_transit_gateway.org_tgw	resource
aws_ec2_transit_gateway_route.blackhole_route	resource
aws_ec2_transit_gateway_route.default_route	resource
aws_ec2_transit_gateway_route.default_route_ipv6	resource
aws_ec2_transit_gateway_route_table.org_tgw	resource
aws_ram_principal_association.org	resource
aws_ram_resource_association.tgw	resource
aws_ram_resource_share.main	resource

Inputs

Name	Description	Type	Default	Required
az_names	A list of the Availability Zone names available to the account	`list(string)`	n/a	yes
cidr	Corporate CIDR range for use with blackholing traffic between production and development environments	`string`	n/a	yes
environment	Deployment environment passed as argument or environment variable	`string`	n/a	yes
inspection_attachment	Inspection VPC attachment for default route	`string`	n/a	yes
org_arn	The ARN of the AWS Organization this account belongs to	`string`	n/a	yes
tgw_route_tables	List of route tables to create for the transit gateway	`list(string)`	n/a	yes

Outputs

Name	Description
tgw	TGW ID for VPC attachments
tgw_route_table	Map of route tables used for association and propagation

IPAM Module

Requirements

No requirements.

Providers

Name	Version
aws	n/a

Modules

No modules.

Resources

Name	Type
aws_ram_principal_association.org	resource
aws_ram_resource_association.ipam	resource
aws_ram_resource_share.main	resource
aws_ssm_parameter.ipam_pool_id	resource
aws_vpc_ipam.org_ipam	resource
aws_vpc_ipam_pool.private_org_ipam_pool	resource
aws_vpc_ipam_pool_cidr.private_org_ipam_pool	resource
aws_vpc_ipam_scope.private_org_ipam_scope	resource

Inputs

Name	Description	Type	Default	Required
aws_region	AWS region being deployed to	`string`	n/a	yes
ipam_cidr	CIDR block assigned to IPAM pool	`string`	n/a	yes
org_arn	The ARN of the AWS Organization this account belongs to	`string`	n/a	yes

Outputs

Name	Description
org_ipam	Org IPAM ID
org_ipam_pool	Org IPAM pool ID

VPC Endpoint Module

Requirements

No requirements.

Providers

Name	Version
aws	n/a

Modules

No modules.

Resources

Name	Type
aws_cloudwatch_log_group.flow_logs	resource
aws_default_security_group.default	resource
aws_ec2_transit_gateway_route_table_association.shared	resource
aws_ec2_transit_gateway_route_table_propagation.org	resource
aws_ec2_transit_gateway_vpc_attachment.vpc_endpoint	resource
aws_flow_log.vpc	resource
aws_route.default_route	resource
aws_route.default_route_ipv6	resource
aws_route53_record.dev_ns	resource
aws_route53_zone.interface_phz	resource
aws_route_table.endpoint_vpc	resource
aws_route_table_association.attachment_subnet	resource
aws_route_table_association.endpoint_subnet	resource
aws_security_group.allow_vpc_endpoint	resource
aws_security_group_rule.org_cidr	resource
aws_subnet.attachment_subnet	resource
aws_subnet.endpoint_subnet	resource
aws_vpc.endpoint_vpc	resource
aws_vpc_dhcp_options.endpoint_vpc	resource
aws_vpc_dhcp_options_association.endpoint_vpc	resource
aws_vpc_endpoint.interface	resource

Inputs

Name	Description	Type	Default	Required
az_names	A list of the Availability Zone names available to the account	`list(string)`	n/a	yes
cidr	Corporate CIDR range for use with blackholing traffic between production and development environments	`string`	n/a	yes
environment	Deployment environment passed as argument or environment variable	`string`	n/a	yes
iam_role_arn	IAM role to allow VPC Flow Logs to write to CloudWatch	`string`	n/a	yes
interface_endpoints	Object representing the region and services to create interface endpoints for	`map(string)`	n/a	yes
kms_key_id	VPC Flow Logs KMS key to encrypt logs	`string`	n/a	yes
org_ipam_pool	IPAM pool ID to allocate CIDR space	`string`	n/a	yes
tgw	TGW ID for VPC attachments	`string`	n/a	yes
tgw_route_tables	TGW route tables for VPC association and propagation	`map(string)`	n/a	yes

Outputs

No outputs.

DNS Module

Requirements

No requirements.

Providers

Name	Version
aws	n/a

Modules

No modules.

Resources

Name	Type
aws_cloudwatch_log_group.flow_logs	resource
aws_default_security_group.default	resource
aws_ec2_transit_gateway_route_table_association.shared	resource
aws_ec2_transit_gateway_route_table_propagation.org	resource
aws_ec2_transit_gateway_vpc_attachment.vpc_dns	resource
aws_flow_log.vpc	resource
aws_ram_principal_association.org	resource
aws_ram_resource_association.r53r	resource
aws_ram_resource_share.main	resource
aws_route.default_route	resource
aws_route.default_route_ipv6	resource
aws_route53_resolver_endpoint.inbound	resource
aws_route53_resolver_endpoint.outbound	resource
aws_route53_resolver_rule.fwd	resource
aws_route53_resolver_rule_association.org_dns	resource
aws_route53_zone.root_private	resource
aws_route_table.dns_vpc	resource
aws_route_table_association.attachment	resource
aws_route_table_association.privatesubnet	resource
aws_security_group.allow_dns	resource
aws_security_group_rule.dns_tcp	resource
aws_subnet.attachment_subnet	resource
aws_subnet.endpoint_subnet	resource
aws_vpc.dns_vpc	resource
aws_vpc_dhcp_options.dns_vpc	resource
aws_vpc_dhcp_options_association.dns_vpc	resource

Inputs

Name	Description	Type	Default	Required
az_names	A list of the Availability Zone names available to the account	`list(string)`	n/a	yes
cidr	Corporate CIDR range for use with blackholing traffic between production and development environments	`string`	n/a	yes
environment	Deployment environment passed as argument or environment variable	`string`	n/a	yes
iam_role_arn	IAM role to allow VPC Flow Logs to write to CloudWatch	`string`	n/a	yes
interface_endpoints	Object representing the region and services to create interface endpoints for	`map(string)`	n/a	yes
kms_key_id	VPC Flow Logs KMS key to encrypt logs	`string`	n/a	yes
org_arn	The ARN of the AWS Organization this account belongs to	`string`	n/a	yes
org_ipam_pool	IPAM pool ID to allocate CIDR space	`string`	n/a	yes
root_domain	Root domain for private hosted zone delegation	`string`	n/a	yes
tgw	TGW ID for VPC attachments	`string`	n/a	yes
tgw_route_tables	TGW route tables for VPC association and propagation	`map(string)`	n/a	yes

Outputs

No outputs.

Network Firewall Module

Requirements

No requirements.

Providers

Name	Version
aws	n/a

Modules

No modules.

Resources

Name	Type
aws_cloudwatch_log_group.flow_logs	resource
aws_cloudwatch_log_group.network_firewall_alert_log_group	resource
aws_cloudwatch_log_group.network_firewall_flow_log_group	resource
aws_default_security_group.default	resource
aws_ec2_transit_gateway_route_table_association.shared	resource
aws_ec2_transit_gateway_route_table_propagation.org	resource
aws_ec2_transit_gateway_vpc_attachment.vpc_inspection	resource
aws_egress_only_internet_gateway.eigw	resource
aws_eip.internet_vpc_nat	resource
aws_flow_log.vpc	resource
aws_internet_gateway.igw	resource
aws_nat_gateway.internet	resource
aws_networkfirewall_firewall.inspection_vpc_network_firewall	resource
aws_networkfirewall_firewall_policy.anfw_policy	resource
aws_networkfirewall_logging_configuration.network_firewall_alert_logging_configuration	resource
aws_networkfirewall_rule_group.block_domains	resource
aws_route.default_route	resource
aws_route.default_route_ipv6	resource
aws_route.egress_route	resource
aws_route.egress_route_ipv6	resource
aws_route.ingress_route	resource
aws_route.inspection_route	resource
aws_route.inspection_route_ipv6	resource
aws_route.inspection_route_natgw_ipv6	resource
aws_route.internal_route	resource
aws_route_table.attachment	resource
aws_route_table.inspection	resource
aws_route_table.internet	resource
aws_route_table_association.attachment_subnet_rt_association	resource
aws_route_table_association.inspection_subnet	resource
aws_route_table_association.internet_subnet	resource
aws_subnet.attachment_subnet	resource
aws_subnet.inspection_subnet	resource
aws_subnet.internet_subnet	resource
aws_vpc.inspection_vpc	resource
aws_vpc_dhcp_options.inspection_vpc	resource
aws_vpc_dhcp_options_association.inspection_vpc	resource

Inputs

Name	Description	Type	Default	Required
aws_region	AWS region being deployed to	`string`	n/a	yes
az_names	A list of the Availability Zone names available to the account	`list(string)`	n/a	yes
cidr	Corporate CIDR range for use with blackholing traffic between production and development environments	`string`	n/a	yes
environment	Deployment environment passed as argument or environment variable	`string`	n/a	yes
iam_role_arn	IAM role to allow VPC Flow Logs to write to CloudWatch	`string`	n/a	yes
kms_key_id	VPC Flow Logs KMS key to encrypt logs	`string`	n/a	yes
org_ipam_pool	IPAM pool ID to allocate CIDR space	`string`	n/a	yes
tgw	TGW ID for VPC attachments	`string`	n/a	yes
tgw_route_tables	TGW route tables for VPC association and propagation	`map(string)`	n/a	yes

Outputs

Name	Description
eni_map	Output ENI map
firewall_info	Info of network firewall for routing
inspection_attachment	Inspection TGW attachment ID for default route in TGW
route_table	Output route tables used for NFW
rt_map	Output RT map

Security

See CONTRIBUTING for more information.

License

This library is licensed under the MIT-0 License. See the LICENSE file.

Name		Name	Last commit message	Last commit date
Latest commit History 48 Commits
example-spoke-vpc		example-spoke-vpc
images		images
modules		modules
.gitignore		.gitignore
.terraform-docs.yml		.terraform-docs.yml
.terraform.lock.hcl		.terraform.lock.hcl
CODE_OF_CONDUCT.md		CODE_OF_CONDUCT.md
CONTRIBUTING.md		CONTRIBUTING.md
LICENSE		LICENSE
README.md		README.md
backend.tf		backend.tf
config.auto.tfvars		config.auto.tfvars
data.tf		data.tf
locals.tf		locals.tf
main.tf		main.tf
outputs.tf		outputs.tf
provider.tf		provider.tf
variables.tf		variables.tf

License

venkatch4/aws-network-hub-for-terraform

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Network Hub Account with Terraform

Table of Contents

Overview

Diagrams

References

Prerequisites

Tooling

AWS account configuration

Customisation

Variables

Quick Start

Deploy from client machine

Tagging

Clean Up

Terraform Docs

Terraform Deployment

Requirements

Providers

Modules

Resources

Inputs

Outputs

TGW Module

Requirements

Providers

Modules

Resources

Inputs

Outputs

IPAM Module

Requirements

Providers

Modules

Resources

Inputs

Outputs

VPC Endpoint Module

Requirements

Providers

Modules

Resources

Inputs

Outputs

DNS Module

Requirements

Providers

Modules

Resources

Inputs

Outputs

Network Firewall Module

Requirements

Providers

Modules

Resources

Inputs

Outputs

Security

License

About

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