Check for required roles and list associated hosts.

src/propertyshelf/fabfile/plone/__init__.py

@@ -4,15 +4,18 @@
 import client
 import database
 import frontend
+import roles
 
 
 client = client  # PyFlakes
 database = database  # PyFlakes
 frontend = frontend  # PyFlakes
+roles = roles
 
 
 __all__ = [
     'client',
     'database',
     'frontend',
+    'roles',
 ]

src/propertyshelf/fabfile/plone/roles.py

@@ -0,0 +1,23 @@
+# -*- coding: utf-8 -*-
+"""Manage chef roles."""
+
+from fabric import api
+from propertyshelf.fabfile.common import roles
+
+
+@api.task
+def check():
+    """Check if the required roles are available."""
+    roles.check_required()
+
+
+@api.task
+def create_missing():
+    """Create missing roles on the chef server."""
+    raise NotImplementedError
+
+
+@api.task
+def list_nodes(role_list=None):
+    """List all available nodes with given roles."""
+    roles.list_nodes()