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Component: tgw/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>

Requirements

NameVersion
terraform>= 1.0.0
aws>= 4.1

Providers

NameVersion
aws>= 4.1
aws.tgw-hub>= 4.1

Modules

NameSourceVersion
cross_region_hub_connectorcloudposse/stack-config/yaml//modules/remote-state1.5.0
iam_roles../../account-map/modules/iam-rolesn/a
tgw_hubcloudposse/stack-config/yaml//modules/remote-state1.5.0
tgw_hub_role../../account-map/modules/iam-rolesn/a
tgw_hub_routescloudposse/transit-gateway/aws0.10.0
tgw_spoke_vpc_attachment./modules/standard_vpc_attachmentn/a
thiscloudposse/label/null0.25.0
vpccloudposse/stack-config/yaml//modules/remote-state1.5.0

Resources

NameType
aws_route.back_routeresource
aws_route.default_routeresource

Inputs

NameDescriptionTypeDefaultRequired
additional_tag_mapAdditional 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
attributesID 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
connectionsA 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
contextSingle 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
cross_region_hub_connector_componentsA 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 compoent 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)
map(object({ component = string, environment = string })){}no
default_route_enabledEnable default routing via transit gateway, requires also nat gateway and instance to be disabled in vpc component. Default is disabled.boolfalseno
default_route_outgoing_account_nameThe account name which is used for outgoing traffic, when using the transit gateway as default route.stringnullno
delimiterDelimiter to be used between ID elements.
Defaults to - (hyphen). Set to "" to use no delimiter at all.
stringnullno
descriptor_formatsDescribe 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
enabledSet to false to prevent the module from creating any resourcesboolnullno
environmentID element. Usually used for region e.g. 'uw2', 'us-west-2', OR role 'prod', 'staging', 'dev', 'UAT'stringnullno
expose_eks_sgSet true to allow EKS clusters to accept traffic from source accountsbooltrueno
id_length_limitLimit 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.
numbernullno
label_key_caseControls 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.
stringnullno
label_orderThe 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)nullno
label_value_caseControls 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.
stringnullno
labels_as_tagsSet 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
nameID 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.
stringnullno
namespaceID element. Usually an abbreviation of your organization name, e.g. 'eg' or 'cp', to help ensure generated IDs are globally uniquestringnullno
own_eks_component_namesThe name of the eks components in the owning account.list(string)[]no
own_vpc_component_nameThe name of the vpc component in the owning account. Defaults to "vpc"string"vpc"no
peered_regionSet true if this region is not the primary regionboolfalseno
regex_replace_charsTerraform 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.
stringnullno
regionAWS Regionstringn/ayes
stageID element. Usually used to indicate role, e.g. 'prod', 'staging', 'source', 'build', 'test', 'deploy', 'release'stringnullno
static_routesA list of static routes to add to the transit gateway, pointing at this VPC as a destination.
set(object({
blackhole = bool
destination_cidr_block = string
}))
[]no
static_tgw_routesA list of static routes to add to the local routing table with the transit gateway as a destination.list(string)[]no
tagsAdditional tags (e.g. {'BusinessUnit': 'XYZ'}).
Neither the tag keys nor the tag values will be modified by this module.
map(string){}no
tenantID element _(Rarely used, not included by default)_. A customer identifier, indicating who this instance of a resource is forstringnullno
tgw_hub_component_nameThe name of the transit-gateway componentstring"tgw/hub"no
tgw_hub_stage_nameThe name of the stage where tgw/hub is provisionedstring"network"no
tgw_hub_tenant_nameThe name of the tenant where tgw/hub is provisioned.

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

Outputs

No outputs.

References