feat: add ZFS facts to prevent zpool disk changes (#410)

- add zfs_zpools and zfs_datasets facts to detect existing ZFS resources
- skip zpool creation when pools already exist

Reviewed-on: #410

modules/zfs/manifests/init.pp

@@ -38,8 +38,11 @@ class zfs (
 
   # create zpools
   $zpools.each | $zpool, $data | {
-    zpool { $zpool:
-      * => $data
+    # Only create zpool if it doesn't already exist
+    if $facts['zfs_zpools'] == undef or !($zpool in $facts['zfs_zpools']) {
+      zpool { $zpool:
+        * => $data
+      }
     }
   }