Split up play into more groups

plays/system.yml

@@ -1,19 +1,25 @@
 ---
-- name: "play : system : ups, smart, zfs : yggdrasil"
+- name: "play : system : ups"
-  hosts: "yggdrasil"
+  hosts: "ups"
   roles:
     - role: "system_ups"
       tags: "role:system_ups"
+
+- name: "play : system : smart"
+  hosts: "smart"
+  roles:
+    - role: "system_smart"
       vars:
         smartd_conf_file_path: "files/system_smart/smartd.conf"
-      when: the_nine_worlds_production | bool
-    - role: "system_smart"
       tags: "role:system_smart"
-      when: the_nine_worlds_production | bool
+
+- name: "play : system : zfs"
+  hosts: "zfs"
+  roles:
     - role: "system_zfs"
       tags: "role:system_zfs"
 
-- name: "play : system : mail, base : all"
+- name: "play : system : all"
   hosts: "all"
   roles:
     - role: "system_mail"

production

@@ -31,6 +31,14 @@ valkyrie
 # Special.
 # --------------------------------------------------------------------------------------------------
 
+# Hosts running with a UPS.
+[ups]
+yggdrasil
+
+# Hosts running with SMART Disk Monitoring Daemon.
+[smart]
+yggdrasil
+
 # Hosts running with ZFS.
 [zfs]
 yggdrasil