This component is responsible for provisioning an AWS Transit Gateway hub that acts as a centralized gateway for connecting VPCs from other spoke accounts.

Usage

Stack Level: Regional

Here's an example snippet for how to configure and use this component:

components:
  terraform:
    tgw/hub/defaults:
      metadata:
        type: abstract
        component: tgw/hub
      vars:
        enabled: true
        name: tgw-hub
        expose_eks_sg: false
        tags:
          Team: sre
          Service: tgw-hub

    tgw/hub:
      metadata:
        inherits:
          - tgw/hub/defaults
        component: tgw/hub
      vars:
        connections:
          - account:
              tenant: core
              stage: network
            vpc_component_names:
              - vpc-dev
          - account:
              tenant: core
              stage: artifacts
          - account:
              tenant: core
              stage: auto
            eks_component_names:
              - eks/cluster
          - account:
              tenant: plat
              stage: dev
            vpc_component_names:
              - vpc
              - vpc/data/1
            eks_component_names:
              - eks/cluster
          - account:
              tenant: plat
              stage: staging
            vpc_component_names:
              - vpc
              - vpc/data/1
            eks_component_names:
              - eks/cluster
          - account:
              tenant: plat
              stage: prod
            vpc_component_names:
              - vpc
              - vpc/data/1
            eks_component_names:
              - eks/cluster

To provision the Transit Gateway and all related resources, run the following commands:

atmos terraform plan tgw/hub -s <tenant>-<environment>-network
atmos terraform apply tgw/hub -s <tenant>-<environment>-network

Requirements

Name	Version
terraform	>= 1.0.0
aws	>= 4.1

Providers

No providers.

Modules

Name	Source	Version
account_map	cloudposse/stack-config/yaml//modules/remote-state	1.5.0
eks	cloudposse/stack-config/yaml//modules/remote-state	1.5.0
iam_roles	../../account-map/modules/iam-roles	n/a
tgw_hub	cloudposse/transit-gateway/aws	0.11.0
this	cloudposse/label/null	0.25.0
vpc	cloudposse/stack-config/yaml//modules/remote-state	1.5.0

Resources

No resources.

Inputs

Name	Description	Type	Default	Required
account_map_environment_name	The name of the environment where account_map is provisioned	string	"gbl"	no
account_map_stage_name	The name of the stage where account_map is provisioned	string	"root"	no
account_map_tenant_name	The name of the tenant where account_map is provisioned. If the tenant label is not used, leave this as null.	string	null	no
additional_tag_map	Additional key-value pairs to add to each map in tags_as_list_of_maps. Not added to tags or id. This is for some rare cases where resources want additional configuration of tags and therefore take a list of maps with tag key, value, and additional configuration.	map(string)	{}	no
allow_external_principals	Set true to allow the TGW to be RAM shared with external principals specified in ram_principals	bool	false	no
attributes	ID element. Additional attributes (e.g. workers or cluster) to add to id, in the order they appear in the list. New attributes are appended to the end of the list. The elements of the list are joined by the delimiter and treated as a single ID element.	list(string)	[]	no
connections	A list of objects to define each TGW connections. By default, each connection will look for only the default vpc component.	list(object({ account = object({ stage = string environment = optional(string, "") tenant = optional(string, "") }) vpc_component_names = optional(list(string), ["vpc"]) eks_component_names = optional(list(string), []) }))	[]	no
context	Single object for setting entire context at once. See description of individual variables for details. Leave string and numeric variables as null to use default value. Individual variable settings (non-null) override settings in context object, except for attributes, tags, and additional_tag_map, which are merged.	any	{ "additional_tag_map": {}, "attributes": [], "delimiter": null, "descriptor_formats": {}, "enabled": true, "environment": null, "id_length_limit": null, "label_key_case": null, "label_order": [], "label_value_case": null, "labels_as_tags": [ "unset" ], "name": null, "namespace": null, "regex_replace_chars": null, "stage": null, "tags": {}, "tenant": null }	no
delimiter	Delimiter to be used between ID elements. Defaults to - (hyphen). Set to "" to use no delimiter at all.	string	null	no
descriptor_formats	Describe additional descriptors to be output in the descriptors output map. Map of maps. Keys are names of descriptors. Values are maps of the form {<br/> format = string<br/> labels = list(string)<br/>} (Type is any so the map values can later be enhanced to provide additional options.) format is a Terraform format string to be passed to the format() function. labels is a list of labels, in order, to pass to format() function. Label values will be normalized before being passed to format() so they will be identical to how they appear in id. Default is {} (descriptors output will be empty).	any	{}	no
enabled	Set to false to prevent the module from creating any resources	bool	null	no
environment	ID element. Usually used for region e.g. 'uw2', 'us-west-2', OR role 'prod', 'staging', 'dev', 'UAT'	string	null	no
expose_eks_sg	Set true to allow EKS clusters to accept traffic from source accounts	bool	true	no
id_length_limit	Limit id to this many characters (minimum 6). Set to 0 for unlimited length. Set to null for keep the existing setting, which defaults to 0. Does not affect id_full.	number	null	no
label_key_case	Controls the letter case of the tags keys (label names) for tags generated by this module. Does not affect keys of tags passed in via the tags input. Possible values: lower, title, upper. Default value: title.	string	null	no
label_order	The order in which the labels (ID elements) appear in the id. Defaults to ["namespace", "environment", "stage", "name", "attributes"]. You can omit any of the 6 labels ("tenant" is the 6th), but at least one must be present.	list(string)	null	no
label_value_case	Controls the letter case of ID elements (labels) as included in id, set as tag values, and output by this module individually. Does not affect values of tags passed in via the tags input. Possible values: lower, title, upper and none (no transformation). Set this to title and set delimiter to "" to yield Pascal Case IDs. Default value: lower.	string	null	no
labels_as_tags	Set of labels (ID elements) to include as tags in the tags output. Default is to include all labels. Tags with empty values will not be included in the tags output. Set to [] to suppress all generated tags. Notes: The value of the name tag, if included, will be the id, not the name. Unlike other null-label inputs, the initial setting of labels_as_tags cannot be changed in later chained modules. Attempts to change it will be silently ignored.	set(string)	[ "default" ]	no
name	ID element. Usually the component or solution name, e.g. 'app' or 'jenkins'. This is the only ID element not also included as a tag. The "name" tag is set to the full id string. There is no tag with the value of the name input.	string	null	no
namespace	ID element. Usually an abbreviation of your organization name, e.g. 'eg' or 'cp', to help ensure generated IDs are globally unique	string	null	no
ram_principals	A list of AWS account IDs to share the TGW with outside the organization	list(string)	[]	no
regex_replace_chars	Terraform regular expression (regex) string. Characters matching the regex will be removed from the ID elements. If not set, "/[^a-zA-Z0-9-]/" is used to remove all characters other than hyphens, letters and digits.	string	null	no
region	AWS Region	string	n/a	yes
stage	ID element. Usually used to indicate role, e.g. 'prod', 'staging', 'source', 'build', 'test', 'deploy', 'release'	string	null	no
tags	Additional tags (e.g. {'BusinessUnit': 'XYZ'}). Neither the tag keys nor the tag values will be modified by this module.	map(string)	{}	no
tenant	ID element _(Rarely used, not included by default)_. A customer identifier, indicating who this instance of a resource is for	string	null	no

Outputs

Name	Description
eks	Accounts with EKS and EKSs information
tgw_config	Transit Gateway config
transit_gateway_arn	Transit Gateway ARN
transit_gateway_id	Transit Gateway ID
transit_gateway_route_table_id	Transit Gateway route table ID
vpcs	Accounts with VPC and VPCs information

References

• cloudposse/terraform-aws-components - Cloud Posse's upstream component

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Related Projects

Check out these related projects.

• Cloud Posse Terraform Modules - Our collection of reusable Terraform modules used by our reference architectures.
• Atmos - Atmos is like docker-compose but for your infrastructure

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