Terraform OVH external DNS records

	Terraform OVH external DNS records
	2023-10-22
	Last edit: 2023-10-22
	---------------------

	Environment replication is always very useful, and I've always made sure that a…

	This turned out to be more useful than expected, given that I had to change ser…

	## Requirements

	The Terraform OVH provider requires certain environment variables:
	- `OVH_ENDPOINT`
	- `OVH_APPLICATION_KEY`
	- `OVH_APPLICATION_SECRET`
	- `OVH_CONSUMER_KEY`

	To access them, simply go to
	OVH's API token creation page
	.

	## Use cases

	For
	theobori.cafe
	, I used the following configurations.

	`providers.tf`
	```hcl
	terraform {
	required_providers {
	ovh = {
	source = "ovh/ovh"
	version = "0.34.0"
	}
	}
	}

	provider "ovh" {
	endpoint = "ovh-eu"
	}
	```

	`variables.tf`
	```hcl
	variable "domain" {
	type = string
	description = "The managed domain name"
	}

	variable "subdomains" {
	type = set(string)
	description = "The subdomains directly link to `var.domain_name`"
	default = [
	"www",
	"status",
	"cringe",
	"etherpad",
	"search",
	"mail",
	"cloud"
	]
	}

	variable "host" {
	type = string
	description = "The target host IPv4 address"
	sensitive = true
	}

	variable "host_ipv6" {
	type = string
	description = "The target host IPv6 address"
	default = null
	sensitive = true
	}

	variable "dkim_key" {
	type = string
	description = "The TXT DNS entry containing the DKIM key"
	default = null
	sensitive = true
	}

	variable "smtp_tlsa" {
	type = string
	description = "The SMTP TLS fingerprint"
	default = null
	sensitive = true
	}
	```

	`main.tf`
	```hcl
	resource "ovh_domain_zone_record" "domain" {
	zone = var.domain
	fieldtype = "A"
	target = var.host
	}

	resource "ovh_domain_zone_record" "www_domain" {
	zone = var.domain
	subdomain = "www"
	fieldtype = "A"
	target = var.host
	}

	resource "ovh_domain_zone_record" "mail" {
	zone = var.domain
	fieldtype = "MX"
	ttl = 300
	target = "10 mail"
	}

	resource "ovh_domain_zone_record" "dmarc" {
	zone = var.domain
	subdomain = "_dmarc"
	fieldtype = "TXT"
	target = "v=DMARC1; p=none; rua=mailto:dmarc@${var.domain}"
	}

	resource "ovh_domain_zone_record" "spf" {
	for_each = toset(
	[
	"",
	"www"
	]
	)

	zone = var.domain
	subdomain = each.key
	fieldtype = "TXT"
	target = "v=spf1 a mx -all"
	}

	resource "ovh_domain_zone_record" "www_txt" {
	zone = var.domain
	fieldtype = "TXT"
	target = "1\|www.${var.domain}"
	}

	resource "ovh_domain_zone_record" "dkim_key" {
	count = var.dkim_key == null ? 0 : 1

	zone = var.domain
	subdomain = "dkim._domainkey"
	fieldtype = "TXT"
	target = var.dkim_key
	}

	resource "ovh_domain_zone_record" "subdomain_entries" {
	for_each = var.subdomains

	zone = var.domain
	subdomain = each.key
	fieldtype = "A"
	target = var.host
	}

	resource "ovh_domain_zone_record" "mail_ipv6" {
	count = var.host_ipv6 == null ? 0 : 1

	zone = var.domain
	subdomain = "mail"
	fieldtype = "AAAA"
	target = var.host_ipv6
	}

	resource "ovh_domain_zone_record" "smtp_fingerprint_tlsa" {
	count = var.smtp_tlsa == null ? 0 : 1

	zone = var.domain
	subdomain = "_25._tcp.mail"
	fieldtype = "TLSA"
	target = var.smtp_tlsa
	}

	resource "ovh_domain_zone_record" "autodiscover" {
	zone = var.domain
	subdomain = "autodiscover"
	fieldtype = "CNAME"
	target = "mail"
	}

	resource "ovh_domain_zone_record" "autoconfig" {
	zone = var.domain
	subdomain = "autoconfig"
	fieldtype = "CNAME"
	target = "mail"
	}
	```

	## Links

	https://github.com/theobori-cafe/dns