spoke

This component is responsible for provisioning AWS Transit Gateway attachments to connect VPCs in a spoke account to different accounts through a central hub.

Usage

Stack Level: Regional

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

stacks/catalog/tgw/spoke.yaml

components:
  terraform:
    tgw/spoke-defaults:
      metadata:
        type: abstract
        component: tgw/spoke
      vars:
        enabled: true
        name: tgw-spoke
        tags:
          Team: sre
          Service: tgw-spoke
        expose_eks_sg: false
        tgw_hub_tenant_name: core
        tgw_hub_environment_name: ue1

    tgw/spoke:
      metadata:
        inherits:
          - tgw/spoke-defaults
      vars:
        # This is what THIS spoke is allowed to connect to.
        # since this is deployed to each plat account (dev->prod),
        # we allow connections to network and auto.
        connections:
          - account:
              tenant: core
              stage: network
            # Set this value if the vpc component has a different name in this account
            vpc_component_names:
              - vpc-dev
          - account:
              tenant: core
              stage: auto

stacks/ue2/dev.yaml

import:
  - catalog/tgw/spoke

components:
  terraform:
    tgw/spoke:
      vars:
        # use when there is not an EKS cluster in the stack
        expose_eks_sg: false
        # override default connections
        connections:
          - account:
              tenant: core
              stage: network
            vpc_component_names:
              - vpc-dev
          - account:
              tenant: core
              stage: auto
          - account:
              tenant: plat
              stage: dev
            eks_component_names:
              - eks/cluster
          - account:
              tenant: plat
              stage: qa
            eks_component_names:
              - eks/cluster

To provision the attachments for a spoke account:

atmos terraform plan tgw/spoke -s <tenant>-<environment>-<stage>
atmos terraform apply tgw/spoke -s <tenant>-<environment>-<stage>

Variables

Required Variables

region (string) required

AWS Region

Optional Variables

connections optional

A list of objects to define each TGW connections.

By default, each connection will look for only the default vpc component.

Type:

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), [])
}))

Default value: [ ]

cross_region_hub_connector_components (map(object({ component = string, environment = string }))) optional

A map of cross-region hub connector components that provide this spoke with the appropriate Transit Gateway attachments IDs.

• The key should be the environment that the remote VPC is located in.
  
• The component is the name of the component in the remote region (e.g. tgw/cross-region-hub-connector)
  
• The environment is the region that the cross-region-hub-connector is deployed in.
  e.g. the following would configure a component called tgw/cross-region-hub-connector/use1 that is deployed in the
  If use2 is the primary region, the following would be its configuration:
  use1:
  component: "tgw/cross-region-hub-connector"
  environment: "use1" (the remote region)
  and in the alternate region, the following would be its configuration:
  use2:
  component: "tgw/cross-region-hub-connector"
  environment: "use1" (our own region)
  

Default value: { }

default_route_enabled (bool) optional

Enable default routing via transit gateway, requires also nat gateway and instance to be disabled in vpc component. Default is disabled.

Default value: false

default_route_outgoing_account_name (string) optional

The account name which is used for outgoing traffic, when using the transit gateway as default route.

Default value: null

expose_eks_sg (bool) optional

Set true to allow EKS clusters to accept traffic from source accounts

Default value: true

own_eks_component_names (list(string)) optional

The name of the eks components in the owning account.

Default value: [ ]

own_vpc_component_name (string) optional

The name of the vpc component in the owning account. Defaults to "vpc"

Default value: "vpc"

peered_region (bool) optional

Set true if this region is not the primary region

Default value: false

static_routes optional

A list of static routes to add to the transit gateway, pointing at this VPC as a destination.

Type:

set(object({
blackhole              = bool
destination_cidr_block = string
}))

Default value: [ ]

static_tgw_routes (list(string)) optional

A list of static routes to add to the local routing table with the transit gateway as a destination.

Default value: [ ]

tgw_hub_component_name (string) optional

The name of the transit-gateway component

Default value: "tgw/hub"

tgw_hub_stage_name (string) optional

The name of the stage where tgw/hub is provisioned

Default value: "network"

tgw_hub_tenant_name (string) optional

The name of the tenant where tgw/hub is provisioned.

If the tenant label is not used, leave this as null.

Default value: null

Context Variables

The following variables are defined in the context.tf file of this module and part of the terraform-null-label pattern.

additional_tag_map (map(string)) optional

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.

Required: No

Default value: { }

attributes (list(string)) optional

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.

Required: No

Default value: [ ]

context (any) optional

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.

Required: No

Default value:

{
  "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
}

delimiter (string) optional

Delimiter to be used between ID elements.
Defaults to - (hyphen). Set to "" to use no delimiter at all.

Required: No

Default value: null

descriptor_formats (any) optional

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).

Required: No

Default value: { }

enabled (bool) optional

Set to false to prevent the module from creating any resources
Required: No

Default value: null

environment (string) optional

ID element. Usually used for region e.g. 'uw2', 'us-west-2', OR role 'prod', 'staging', 'dev', 'UAT'
Required: No

Default value: null

id_length_limit (number) optional

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.

Required: No

Default value: null

label_key_case (string) optional

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.

Required: No

Default value: null

label_order (list(string)) optional

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.

Required: No

Default value: null

label_value_case (string) optional

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.

Required: No

Default value: null

labels_as_tags (set(string)) optional

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.

Required: No

Default value:

[
  "default"
]

name (string) optional

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.

Required: No

Default value: null

namespace (string) optional

ID element. Usually an abbreviation of your organization name, e.g. 'eg' or 'cp', to help ensure generated IDs are globally unique
Required: No

Default value: null

regex_replace_chars (string) optional

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.

Required: No

Default value: null

stage (string) optional

ID element. Usually used to indicate role, e.g. 'prod', 'staging', 'source', 'build', 'test', 'deploy', 'release'
Required: No

Default value: null

tags (map(string)) optional

Additional tags (e.g. {'BusinessUnit': 'XYZ'}).
Neither the tag keys nor the tag values will be modified by this module.

Required: No

Default value: { }

tenant (string) optional

ID element (Rarely used, not included by default). A customer identifier, indicating who this instance of a resource is for
Required: No

Default value: null

Dependencies

Requirements

• terraform, version: >= 1.0.0
• aws, version: >= 4.1

Providers

• aws, version: >= 4.1
• aws, version: >= 4.1

Modules

Name	Version	Source	Description
cross_region_hub_connector	1.8.0	cloudposse/stack-config/yaml//modules/remote-state	n/a
iam_roles	latest	../../account-map/modules/iam-roles	n/a
tgw_hub	1.8.0	cloudposse/stack-config/yaml//modules/remote-state	n/a
tgw_hub_role	latest	../../account-map/modules/iam-roles	n/a
tgw_hub_routes	0.11.3	cloudposse/transit-gateway/aws	n/a
tgw_spoke_vpc_attachment	latest	./modules/standard_vpc_attachment	n/a
this	0.25.0	cloudposse/label/null	n/a
vpc	1.8.0	cloudposse/stack-config/yaml//modules/remote-state	n/a

Resources

The following resources are used by this module:

• aws_route.back_route (resource)
• aws_route.default_route (resource)

Data Sources

The following data sources are used by this module:

References

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