Add optional cluster_domain_suffix variable

* Allow kube-dns to respond to DNS queries with a custom
suffix, instead of the default 'cluster.local'
* Useful when multiple clusters exist on the same local
network and wish to query services on one another

bare-metal/container-linux/kubernetes/bootkube.tf

@@ -2,12 +2,13 @@
 module "bootkube" {
   source = "git::https://github.com/poseidon/terraform-render-bootkube.git?ref=v0.9.1"
 
-  cluster_name = "${var.cluster_name}"
-  api_servers  = ["${var.k8s_domain_name}"]
-  etcd_servers = ["${var.controller_domains}"]
-  asset_dir    = "${var.asset_dir}"
-  networking   = "${var.networking}"
-  network_mtu  = "${var.network_mtu}"
-  pod_cidr     = "${var.pod_cidr}"
-  service_cidr = "${var.service_cidr}"
+  cluster_name          = "${var.cluster_name}"
+  api_servers           = ["${var.k8s_domain_name}"]
+  etcd_servers          = ["${var.controller_domains}"]
+  asset_dir             = "${var.asset_dir}"
+  networking            = "${var.networking}"
+  network_mtu           = "${var.network_mtu}"
+  pod_cidr              = "${var.pod_cidr}"
+  service_cidr          = "${var.service_cidr}"
+  cluster_domain_suffix = "${var.cluster_domain_suffix}"
 }

bare-metal/container-linux/kubernetes/cl/controller.yaml.tmpl

@@ -82,7 +82,7 @@ systemd:
           --anonymous-auth=false \
           --client-ca-file=/etc/kubernetes/ca.crt \
           --cluster_dns=${k8s_dns_service_ip} \
-          --cluster_domain=cluster.local \
+          --cluster_domain=${cluster_domain_suffix} \
           --cni-conf-dir=/etc/kubernetes/cni/net.d \
           --exit-on-lock-contention \
           --hostname-override=${domain_name} \

bare-metal/container-linux/kubernetes/cl/worker.yaml.tmpl

@@ -58,7 +58,7 @@ systemd:
           --anonymous-auth=false \
           --client-ca-file=/etc/kubernetes/ca.crt \
           --cluster_dns=${k8s_dns_service_ip} \
-          --cluster_domain=cluster.local \
+          --cluster_domain=${cluster_domain_suffix} \
           --cni-conf-dir=/etc/kubernetes/cni/net.d \
           --exit-on-lock-contention \
           --hostname-override=${domain_name} \

bare-metal/container-linux/kubernetes/profiles.tf

@@ -84,11 +84,12 @@ data "template_file" "controller-configs" {
   template = "${file("${path.module}/cl/controller.yaml.tmpl")}"
 
   vars {
-    domain_name          = "${element(var.controller_domains, count.index)}"
-    etcd_name            = "${element(var.controller_names, count.index)}"
-    etcd_initial_cluster = "${join(",", formatlist("%s=https://%s:2380", var.controller_names, var.controller_domains))}"
-    k8s_dns_service_ip   = "${module.bootkube.kube_dns_service_ip}"
-    ssh_authorized_key   = "${var.ssh_authorized_key}"
+    domain_name           = "${element(var.controller_domains, count.index)}"
+    etcd_name             = "${element(var.controller_names, count.index)}"
+    etcd_initial_cluster  = "${join(",", formatlist("%s=https://%s:2380", var.controller_names, var.controller_domains))}"
+    k8s_dns_service_ip    = "${module.bootkube.kube_dns_service_ip}"
+    cluster_domain_suffix = "${var.cluster_domain_suffix}"
+    ssh_authorized_key    = "${var.ssh_authorized_key}"
 
     # Terraform evaluates both sides regardless and element cannot be used on 0 length lists
     networkd_content = "${length(var.controller_networkds) == 0 ? "" : element(concat(var.controller_networkds, list("")), count.index)}"
@@ -108,9 +109,10 @@ data "template_file" "worker-configs" {
   template = "${file("${path.module}/cl/worker.yaml.tmpl")}"
 
   vars {
-    domain_name        = "${element(var.worker_domains, count.index)}"
-    k8s_dns_service_ip = "${module.bootkube.kube_dns_service_ip}"
-    ssh_authorized_key = "${var.ssh_authorized_key}"
+    domain_name           = "${element(var.worker_domains, count.index)}"
+    k8s_dns_service_ip    = "${module.bootkube.kube_dns_service_ip}"
+    cluster_domain_suffix = "${var.cluster_domain_suffix}"
+    ssh_authorized_key    = "${var.ssh_authorized_key}"
 
     # Terraform evaluates both sides regardless and element cannot be used on 0 length lists
     networkd_content = "${length(var.worker_networkds) == 0 ? "" : element(concat(var.worker_networkds, list("")), count.index)}"

bare-metal/container-linux/kubernetes/variables.tf

@@ -92,6 +92,12 @@ EOD
 
 # optional
 
+variable "cluster_domain_suffix" {
+  description = "Queries for domains with the suffix will be answered by kube-dns. Default is cluster.local (e.g. foo.default.svc.cluster.local) "
+  type        = "string"
+  default     = "cluster.local"
+}
+
 variable "cached_install" {
   type        = "string"
   default     = "false"