baremetal: sets hostname controller_names/worker_names

Sets the hostname from the `<cluster_name>-worker-<count_index>` which
is set when `set_standard_hostname` is true, to
`controller_names<count_index>` for controllers and
`worker_names<count_index>` for workers

The hostname change got introduced by #1477 where it was set from the
template variable `domain_name` coming from
var.controller_domains[count.index]

assets/terraform-modules/bare-metal/flatcar-linux/kubernetes/controller.tf

@@ -10,6 +10,17 @@ module "controller" {
   apiserver              = format("%s.%s", var.cluster_name, var.k8s_domain_name)
   ca_cert                = module.bootkube.ca_cert
   kubelet_labels         = lookup(var.node_specific_labels, var.controller_names[count.index], {})
-  clc_snippets           = lookup(var.clc_snippets, var.controller_names[count.index], [])
-  set_standard_hostname  = true
+  set_standard_hostname  = false
+  clc_snippets = concat(lookup(var.clc_snippets, var.controller_names[count.index], []), [
+    <<EOF
+storage:
+  files:
+    - path: /etc/hostname
+      filesystem: root
+      mode: 0644
+      contents:
+        inline: ${var.controller_names[count.index]}
+EOF
+    ,
+  ])
 }

assets/terraform-modules/bare-metal/flatcar-linux/kubernetes/worker.tf

@@ -9,7 +9,18 @@ module "worker" {
   apiserver              = format("%s.%s", var.cluster_name, var.k8s_domain_name)
   kubelet_labels         = merge(lookup(var.node_specific_labels, var.worker_names[count.index], {}), var.labels)
   cluster_name           = var.cluster_name
-  clc_snippets           = lookup(var.clc_snippets, var.worker_names[count.index], [])
-  set_standard_hostname  = true
+  set_standard_hostname  = false
+  clc_snippets = concat(lookup(var.clc_snippets, var.worker_names[count.index], []), [
+    <<EOF
+storage:
+  files:
+    - path: /etc/hostname
+      filesystem: root
+      mode: 0644
+      contents:
+        inline: ${var.worker_names[count.index]}
+EOF
+    ,
+  ])
 }