bundles/vmhost: add metadata reactor to add all admins to 'libvirt' group

bundles/vmhost/metadata.py

@@ -35,3 +35,21 @@ if node.has_bundle('nftables'):
             'pkg_apt:libvirt-daemon-system',
         },
     }
+
+
+@metadata_reactor.provides(
+    'users',
+)
+def libvirt_group_for_admins(metadata):
+    result = {}
+    for user, config in metadata.get('users', {}).items():
+        if config.get('is_admin', False):
+            result[user] = {
+                'groups': {
+                    'libvirt',
+                },
+            }
+
+    return {
+        'users': result,
+    }