Component: `dns-primary`

This component is responsible for provisioning the primary DNS zones into an AWS account. By convention, we typically provision the primary DNS zones in the dns account. The primary account for branded zones (e.g. example.com), however, would be in the prod account, while staging zone (e.g. example.qa) might be in the staging account.

The zones from the primary DNS zone are then expected to be delegated to other accounts via the dns-delegated component. Additionally, external records can be created on the primary DNS zones via the record_config variable.

Architecture

Summary

The dns account gets a single dns-primary component deployed. Every other account that needs DNS entries gets a single dns-delegated component, chaining off the domains in the dns account. Optionally, accounts can have a single dns-primary component of their own, to have apex domains (which Cloud Posse calls "vanity domains"). Typically, these domains are configured with CNAME (or apex alias) records to point to service domain entries.

Details

The purpose of the dns account is to host root domains shared by several accounts (with each account being delegated its own subdomain) and to be the owner of domain registrations purchased from Amazon.

The purpose of the dns-primary component is to provision AWS Route53 zones for the root domains. These zones, once provisioned, must be manually configured into the Domain Name Registrar's records as name servers. A single component can provision multiple domains and, optionally, associated ACM (SSL) certificates in a single account.

Cloud Posse's architecture expects root domains shared by several accounts to be provisioned in the dns account with dns-primary and delegated to other accounts using the dns-delegated component, with each account getting its own subdomain corresponding to a Route 53 zone in the delegated account. Cloud Posse's architecture requires at least one such domain, called "the service domain", be provisioned. The service domain is not customer facing, and is provisioned to allow fully automated construction of host names without any concerns about how they look. Although they are not secret, the public will never see them.

Root domains used by a single account are provisioned with the dns-primary component directly in that account. Cloud Posse calls these "vanity domains". These can be whatever the marketing or PR or other stakeholders want to be.

After a domain is provisioned in the dns account, the dns-delegated component can provision one or more subdomains for each account, and, optionally, associated ACM certificates. For the service domain, Cloud Posse recommends using the account name as the delegated subdomain (either directly, e.g. "plat-dev", or as multiple subdomains, e.g. "dev.plat") because that allows dns-delegated to automatically provision any required host name in that zone.

There is no automated support for dns-primary to provision root domains outside of the dns account that are to be shared by multiple accounts, and such usage is not recommended. If you must, dns-primary can provision a subdomain of a root domain that is provisioned in another account (not dns). In this case, the delegation of the subdomain must be done manually by entering the name servers into the parent domain's records (instead of in the Registrar's records).

The architecture does not support other configurations, or non-standard component names.

Usage

Stack Level: Global

Here's an example snippet for how to use this component. This component should only be applied once as the DNS zones it creates are global. This is typically done via the DNS stack (e.g. gbl-dns.yaml).

components:
  terraform:
    dns-primary:
      vars:
        domain_names:
          - example.net
        record_config:
          - root_zone: example.net
            name: ""
            type: A
            ttl: 60
            records:
              - 53.229.170.215
          # using a period at the end of a name
          - root_zone: example.net
            name: www.
            type: CNAME
            ttl: 60
            records:
              - example.net
          # using numbers as name requires quotes
          - root_zone: example.net
            name: "123456."
            type: CNAME
            ttl: 60
            records:
              - example.net
          # strings that are very long, this could be a DKIM key
          - root_zone: example.net
            name: service._domainkey.
            type: CNAME
            ttl: 60
            records:
              - !!str |-
                YourVeryLongStringGoesHere

Use the acm component for more advanced certificate

requirements.

Requirements

Name	Version
terraform	>= 1.0.0
aws	>= 4.9.0

Providers

Name	Version
aws	>= 4.9.0

Modules

Name	Source	Version
acm	cloudposse/acm-request-certificate/aws	0.16.3
iam_roles	../account-map/modules/iam-roles	n/a
this	cloudposse/label/null	0.25.0

Resources

Name	Type
aws_route53_record.aliasrec	resource
aws_route53_record.dnsrec	resource
aws_route53_record.soa	resource
aws_route53_zone.root	resource

Inputs

Name	Description	Type	Default	Required
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
alias_record_config	DNS Alias Record config	`list(object({ root_zone = string name = string type = string zone_id = string record = string evaluate_target_health = bool }))`	`[]`	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
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
dns_soa_config	Root domain name DNS SOA record: - awsdns-hostmaster.amazon.com. ; AWS default value for administrator email address - 1 ; serial number, not used by AWS - 7200 ; refresh time in seconds for secondary DNS servers to refreh SOA record - 900 ; retry time in seconds for secondary DNS servers to retry failed SOA record update - 1209600 ; expire time in seconds (1209600 is 2 weeks) for secondary DNS servers to remove SOA record if they cannot refresh it - 60 ; nxdomain TTL, or time in seconds for secondary DNS servers to cache negative responses See SOA Record Documentation for more information.	`string`	`"awsdns-hostmaster.amazon.com. 1 7200 900 1209600 60"`	no
domain_names	Root domain name list, e.g. `["example.net"]`	`list(string)`	`null`	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
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
record_config	DNS Record config	`list(object({ root_zone = string name = string type = string ttl = string records = 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
request_acm_certificate	Whether or not to request an ACM certificate for each domain	`bool`	`false`	no
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
acms	ACM certificates for domains
zones	DNS zones

References

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

Component: dns-primary

Architecture​

Summary​

Details​

Usage​

Requirements​

Providers​

Modules​

Resources​

Inputs​

Outputs​

References​