bundles/postgresql: use zfs if possible

bundles/postgresql/items.py

@@ -3,21 +3,43 @@ pkg_apt = {
     'postgresql-client-11': {},
 }
 
+if node.has_bundle('zfs'):
+    pkg_apt['postgresql-11']['needs'] = {
+        'zfs_dataset:tank/postgresql',
+    }
+
 postgres_roles = {
     'root': {
         'password': repo.vault.password_for('{} postgresql root'.format(node.name)),
         'superuser': True,
+        'needs': {
+            'svc_systemd:postgresql',
+        },
+    },
+}
+
+svc_systemd = {
+    'postgresql': {
+        'needs': {
+            'pkg_apt:postgresql-11',
+        },
     },
 }
 
 postgres_dbs = {}
 
-for user, config in node.metadata['postgresql']['users'].items():
+for user, config in node.metadata.get('postgresql', {}).get('users', {}).items():
     postgres_roles[user] = {
         'password': config['password'],
+        'needs': {
+            'svc_systemd:postgresql',
+        },
     }
 
-for database, config in node.metadata['postgresql']['databases'].items():
+for database, config in node.metadata.get('postgresql', {}).get('databases', {}).items():
     postgres_dbs[database] = {
         'owner': config['owner'],
+        'needs': {
+            'svc_systemd:postgresql',
+        },
     }

bundles/postgresql/metadata.py

@@ -0,0 +1,10 @@
+defaults = {}
+
+if node.has_bundle('zfs'):
+    defaults['zfs'] = {
+        'datasets': {
+            'tank/postgresql': {
+                'mountpoint': '/var/lib/postgresql',
+            },
+        },
+    }