geo_dns: support geo domains with subset of hosts

Useful if we wanted to create a Geo-based archive consisting of machines
in the archive_mirrors group (though this will likely not happen because
it'd break archlinux-repro due to the ~4 hour sync delay).

group_vars/all/geo.yml

 geo_acme_dns_challenge_ns: redirect.archlinux.org
 geo_domains:
   - geo.mirror.pkgbuild.com
+# geo_options.*.hosts defaults to "{{ groups['geo_mirrors'] }}"
 geo_options:
   geo.mirror.pkgbuild.com:
     health_check_path: /lastupdate

roles/geo_dns/templates/geo.yml.j2

 #jinja2:lstrip_blocks: True
 domains:
   {% for domain in geo_domains %}
+  {% set hosts = geo_options[domain]['hosts'] | default(groups['geo_mirrors']) %}
   - domain: {{ domain }}
     ttl: 3600
     records:
@@ -15,13 +16,13 @@ domains:
             ttl: 300
             content: >
               A "ifurlup('https://{{ domain }}{{ geo_options[domain]['health_check_path'] | default('/') }}',
-              {'{{ groups['geo_mirrors'] | map('extract', hostvars, ['ipv4_address']) | join("', '") }}'},
+              {'{{ hosts | map('extract', hostvars, ['ipv4_address']) | join("', '") }}'},
               {selector='pickclosest', useragent='pdns on {{ inventory_hostname }}'})"
         - lua:
             ttl: 300
             content: >
               AAAA "ifurlup('https://{{ domain }}{{ geo_options[domain]['health_check_path'] | default('/') }}',
-              {'{{ groups['geo_mirrors'] | map('extract', hostvars, ['ipv6_address']) | join("', '") }}'},
+              {'{{ hosts | map('extract', hostvars, ['ipv6_address']) | join("', '") }}'},
               {selector='pickclosest', useragent='pdns on {{ inventory_hostname }}'})"
       _acme-challenge.{{ domain }}:
         - ns: {{ geo_acme_dns_challenge_ns }}

roles/prometheus_exporters/templates/blackbox.yml.j2

@@ -26,6 +26,7 @@ modules:
         - expect: "^250"
         - send: "QUIT\r"
   {% for domain in geo_domains %}
+  {% set hosts = geo_options[domain]['hosts'] | default(groups['geo_mirrors']) %}
   geo_dns_{{ domain }}_a:
     prober: dns
     timeout: 5s
@@ -35,7 +36,7 @@ modules:
       preferred_ip_protocol: ip4
       validate_answer_rrs:
         fail_if_not_matches_regexp:
-          - {{ domain | replace('.', '\.') }}\.\t.*\tIN\tA\t({{ groups['geo_mirrors'] | map('extract', hostvars, ['ipv4_address']) | join('|') | replace('.', '\.') }})
+          - {{ domain | replace('.', '\.') }}\.\t.*\tIN\tA\t({{ hosts | map('extract', hostvars, ['ipv4_address']) | join('|') | replace('.', '\.') }})
   geo_dns_{{ domain }}_aaaa:
     prober: dns
     timeout: 5s
@@ -45,5 +46,5 @@ modules:
       preferred_ip_protocol: ip6
       validate_answer_rrs:
         fail_if_not_matches_regexp:
-          - {{ domain | replace('.', '\.') }}\.\t.*\tIN\tAAAA\t({{ groups['geo_mirrors'] | map('extract', hostvars, ['ipv6_address']) | join('|') }})
+          - {{ domain | replace('.', '\.') }}\.\t.*\tIN\tAAAA\t({{ hosts | map('extract', hostvars, ['ipv6_address']) | join('|') }})
   {% endfor %}

tf-stage1/archlinux.tf

@@ -397,8 +397,8 @@ locals {
 
   # Domains served by machines in the geo_mirrors group
   # Valid parameters are:
-  #   - zone_id (mandatory, either of hetznerdns_zone.{archlinux,pkgbuild}.id)
   #   - name (mandatory, specifies the subdomain to create in the above zone)
+  #   - zone (optional, defaults to hetznerdns_zone.archlinux.id)
   #   - ttl (optional, the TTL of the NS records, defaults to 86400 if unset)
   #
   # Note: If you use a custom TTL, also add it to geo_options[domain]['ns_ttl']
@@ -406,8 +406,8 @@ locals {
   #
   geo_domains = {
     "geo.mirror.pkgbuild.com" = {
-      zone_id = hetznerdns_zone.pkgbuild.id
-      name    = "geo.mirror"
+      name = "geo.mirror"
+      zone = hetznerdns_zone.pkgbuild.id
     }
   }
 }

tf-stage1/templates.tf

@@ -185,7 +185,7 @@ resource "hetznerdns_record" "machine_aaaa" {
 resource "hetznerdns_record" "geo_ns1" {
   for_each = local.geo_domains
 
-  zone_id = each.value.zone_id
+  zone_id = lookup(each.value, "zone", hetznerdns_zone.archlinux.id)
   name    = each.value.name
   value   = "america.mirror.pkgbuild.com."
   type    = "NS"
@@ -195,7 +195,7 @@ resource "hetznerdns_record" "geo_ns1" {
 resource "hetznerdns_record" "geo_ns2" {
   for_each = local.geo_domains
 
-  zone_id = each.value.zone_id
+  zone_id = lookup(each.value, "zone", hetznerdns_zone.archlinux.id)
   name    = each.value.name
   value   = "asia.mirror.pkgbuild.com."
   type    = "NS"
@@ -205,7 +205,7 @@ resource "hetznerdns_record" "geo_ns2" {
 resource "hetznerdns_record" "geo_ns3" {
   for_each = local.geo_domains
 
-  zone_id = each.value.zone_id
+  zone_id = lookup(each.value, "zone", hetznerdns_zone.archlinux.id)
   name    = each.value.name
   value   = "europe.mirror.pkgbuild.com."
   type    = "NS"
@@ -215,7 +215,7 @@ resource "hetznerdns_record" "geo_ns3" {
 resource "hetznerdns_record" "geo_ns4" {
   for_each = local.geo_domains
 
-  zone_id = each.value.zone_id
+  zone_id = lookup(each.value, "zone", hetznerdns_zone.archlinux.id)
   name    = each.value.name
   value   = "seoul.mirror.pkgbuild.com."
   type    = "NS"
@@ -225,7 +225,7 @@ resource "hetznerdns_record" "geo_ns4" {
 resource "hetznerdns_record" "geo_ns5" {
   for_each = local.geo_domains
 
-  zone_id = each.value.zone_id
+  zone_id = lookup(each.value, "zone", hetznerdns_zone.archlinux.id)
   name    = each.value.name
   value   = "sydney.mirror.pkgbuild.com."
   type    = "NS"