diff --git a/archlinux.tf b/archlinux.tf
index e4a8f3731dd80cca3f1e5ea67761246fa90559ea..42ad66ef7d56a70b8c322e1ad41f6126c433a0e3 100644
--- a/archlinux.tf
+++ b/archlinux.tf
@@ -1,5 +1,6 @@
 terraform {
-  backend "pg" {}
+  backend "pg" {
+  }
 }
 
 data "external" "hetzner_cloud_api_key" {
@@ -8,23 +9,23 @@ data "external" "hetzner_cloud_api_key" {
 
 data "hcloud_image" "archlinux" {
   with_selector = "custom_image=archlinux"
-  most_recent = true
-  with_status = ["available"]
+  most_recent   = true
+  with_status   = ["available"]
 }
 
 provider "hcloud" {
-  token = "${data.external.hetzner_cloud_api_key.result.hetzner_cloud_api_key}"
+  token = data.external.hetzner_cloud_api_key.result.hetzner_cloud_api_key
 }
 
 resource "hcloud_rdns" "quassel" {
-  server_id  = "${hcloud_server.quassel.id}"
-  ip_address = "${hcloud_server.quassel.ipv4_address}"
+  server_id  = hcloud_server.quassel.id
+  ip_address = hcloud_server.quassel.ipv4_address
   dns_ptr    = "quassel.archlinux.org"
 }
 
 resource "hcloud_server" "quassel" {
   name        = "quassel.archlinux.org"
-  image       = "${data.hcloud_image.archlinux.id}"
+  image       = data.hcloud_image.archlinux.id
   server_type = "cx11"
   lifecycle {
     ignore_changes = [image]
@@ -32,14 +33,14 @@ resource "hcloud_server" "quassel" {
 }
 
 resource "hcloud_rdns" "phrik" {
-  server_id  = "${hcloud_server.phrik.id}"
-  ip_address = "${hcloud_server.phrik.ipv4_address}"
+  server_id  = hcloud_server.phrik.id
+  ip_address = hcloud_server.phrik.ipv4_address
   dns_ptr    = "phrik.archlinux.org"
 }
 
 resource "hcloud_server" "phrik" {
   name        = "phrik.archlinux.org"
-  image       = "${data.hcloud_image.archlinux.id}"
+  image       = data.hcloud_image.archlinux.id
   server_type = "cx11"
   lifecycle {
     ignore_changes = [image]
@@ -47,14 +48,14 @@ resource "hcloud_server" "phrik" {
 }
 
 resource "hcloud_rdns" "bbs" {
-  server_id  = "${hcloud_server.bbs.id}"
-  ip_address = "${hcloud_server.bbs.ipv4_address}"
+  server_id  = hcloud_server.bbs.id
+  ip_address = hcloud_server.bbs.ipv4_address
   dns_ptr    = "bbs.archlinux.org"
 }
 
 resource "hcloud_server" "bbs" {
   name        = "bbs.archlinux.org"
-  image       = "${data.hcloud_image.archlinux.id}"
+  image       = data.hcloud_image.archlinux.id
   server_type = "cx21"
   lifecycle {
     ignore_changes = [image]
@@ -62,14 +63,14 @@ resource "hcloud_server" "bbs" {
 }
 
 resource "hcloud_rdns" "gitlab" {
-  server_id  = "${hcloud_server.gitlab.id}"
-  ip_address = "${hcloud_server.gitlab.ipv4_address}"
+  server_id  = hcloud_server.gitlab.id
+  ip_address = hcloud_server.gitlab.ipv4_address
   dns_ptr    = "gitlab.archlinux.org"
 }
 
 resource "hcloud_server" "gitlab" {
   name        = "gitlab.archlinux.org"
-  image       = "${data.hcloud_image.archlinux.id}"
+  image       = data.hcloud_image.archlinux.id
   server_type = "cx21"
   lifecycle {
     ignore_changes = [image]
@@ -77,14 +78,14 @@ resource "hcloud_server" "gitlab" {
 }
 
 resource "hcloud_rdns" "matrix" {
-  server_id  = "${hcloud_server.matrix.id}"
-  ip_address = "${hcloud_server.matrix.ipv4_address}"
+  server_id  = hcloud_server.matrix.id
+  ip_address = hcloud_server.matrix.ipv4_address
   dns_ptr    = "matrix.archlinux.org"
 }
 
 resource "hcloud_server" "matrix" {
   name        = "matrix.archlinux.org"
-  image       = "${data.hcloud_image.archlinux.id}"
+  image       = data.hcloud_image.archlinux.id
   server_type = "cx21"
   lifecycle {
     ignore_changes = [image]
@@ -92,14 +93,14 @@ resource "hcloud_server" "matrix" {
 }
 
 resource "hcloud_rdns" "ciprototype" {
-  server_id  = "${hcloud_server.ciprototype.id}"
-  ip_address = "${hcloud_server.ciprototype.ipv4_address}"
+  server_id  = hcloud_server.ciprototype.id
+  ip_address = hcloud_server.ciprototype.ipv4_address
   dns_ptr    = "ciprototype.archlinux.org"
 }
 
 resource "hcloud_server" "ciprototype" {
   name        = "ciprototype.archlinux.org"
-  image       = "${data.hcloud_image.archlinux.id}"
+  image       = data.hcloud_image.archlinux.id
   server_type = "cx21"
   lifecycle {
     ignore_changes = [image]
@@ -107,14 +108,14 @@ resource "hcloud_server" "ciprototype" {
 }
 
 resource "hcloud_rdns" "acccounts" {
-  server_id  = "${hcloud_server.accounts.id}"
-  ip_address = "${hcloud_server.accounts.ipv4_address}"
+  server_id  = hcloud_server.accounts.id
+  ip_address = hcloud_server.accounts.ipv4_address
   dns_ptr    = "accounts.archlinux.org"
 }
 
 resource "hcloud_server" "accounts" {
   name        = "accounts.archlinux.org"
-  image       = "${data.hcloud_image.archlinux.id}"
+  image       = data.hcloud_image.archlinux.id
   server_type = "cx11"
   lifecycle {
     ignore_changes = [image]
@@ -122,16 +123,17 @@ resource "hcloud_server" "accounts" {
 }
 
 resource "hcloud_rdns" "mirror" {
-  server_id  = "${hcloud_server.mirror.id}"
-  ip_address = "${hcloud_server.mirror.ipv4_address}"
+  server_id  = hcloud_server.mirror.id
+  ip_address = hcloud_server.mirror.ipv4_address
   dns_ptr    = "mirror.pkgbuild.com"
 }
 
 resource "hcloud_server" "mirror" {
   name        = "mirror.pkgbuild.com"
-  image       = "${data.hcloud_image.archlinux.id}"
+  image       = data.hcloud_image.archlinux.id
   server_type = "cx11"
   lifecycle {
     ignore_changes = [image]
   }
 }
+
diff --git a/versions.tf b/versions.tf
new file mode 100644
index 0000000000000000000000000000000000000000..ac97c6ac8e7c1ce3bd191e54af4c6c57fa93643e
--- /dev/null
+++ b/versions.tf
@@ -0,0 +1,4 @@
+
+terraform {
+  required_version = ">= 0.12"
+}