diff --git a/savanna/plugins/provisioning.py b/savanna/plugins/provisioning.py
index 90495a31..84e68241 100644
--- a/savanna/plugins/provisioning.py
+++ b/savanna/plugins/provisioning.py
@@ -85,7 +85,7 @@ class Config(resources.BaseResource):
         "some_conf", "map_reduce", "node", is_optional=True
     """
 
-    def __init__(self, name, applicable_target, scope, config_type="str",
+    def __init__(self, name, applicable_target, scope, config_type="string",
                  config_values=None, default_value=None, is_optional=False,
                  description=None, priority=2):
         self.name = name
diff --git a/savanna/plugins/vanilla/config_helper.py b/savanna/plugins/vanilla/config_helper.py
index a90a44b2..5e168914 100644
--- a/savanna/plugins/vanilla/config_helper.py
+++ b/savanna/plugins/vanilla/config_helper.py
@@ -47,23 +47,27 @@ ENV_CONFS = {
     }
 }
 
+HIDDEN_CONFS = ['fs.default.name', 'dfs.name.dir', 'dfs.data.dir',
+                'mapred.job.tracker', 'mapred.system.dir', 'mapred.local.dir']
+
 
 def _initialise_configs():
     configs = []
     for service, config_lists in XML_CONFS.iteritems():
         for config_list in config_lists:
             for config in config_list:
-                cfg = p.Config(config['name'], service, "node",
-                               is_optional=True, config_type="str",
-                               default_value=str(config['value']),
-                               description=config['description'])
-                if cfg.default_value in ["true", "false"]:
-                    cfg.config_type = "bool"
-                    cfg.default_value = (cfg.default_value == 'true')
-                if str(cfg.default_value).isdigit():
-                    cfg.config_type = "int"
-                    cfg.default_value = int(cfg.default_value)
-                configs.append(cfg)
+                if config['name'] not in HIDDEN_CONFS:
+                    cfg = p.Config(config['name'], service, "node",
+                                   is_optional=True, config_type="string",
+                                   default_value=str(config['value']),
+                                   description=config['description'])
+                    if cfg.default_value in ["true", "false"]:
+                        cfg.config_type = "bool"
+                        cfg.default_value = (cfg.default_value == 'true')
+                    if str(cfg.default_value).isdigit():
+                        cfg.config_type = "int"
+                        cfg.default_value = int(cfg.default_value)
+                    configs.append(cfg)
 
     for service, config_items in ENV_CONFS.iteritems():
         for name, param_format_str in config_items.iteritems():
diff --git a/savanna/tests/unit/plugins/vanilla/test_plugin.py b/savanna/tests/unit/plugins/vanilla/test_plugin.py
index a85d4d4e..36ae20e9 100644
--- a/savanna/tests/unit/plugins/vanilla/test_plugin.py
+++ b/savanna/tests/unit/plugins/vanilla/test_plugin.py
@@ -62,6 +62,7 @@ class VanillaPluginTest(unittest2.TestCase):
                 self.assertIsInstance(cfg.default_value, int)
             else:
                 self.assertIsInstance(cfg.default_value, str)
+            self.assertNotIn(cfg.name, c_h.HIDDEN_CONFS)
 
     def test_extract_environment_configs(self):
         env_configs = {
diff --git a/savanna/tests/unit/utils/test_xml_utils.py b/savanna/tests/unit/utils/test_xml_utils.py
index ea74c8c2..4198b7f1 100644
--- a/savanna/tests/unit/utils/test_xml_utils.py
+++ b/savanna/tests/unit/utils/test_xml_utils.py
@@ -45,13 +45,13 @@ class XMLUtilsTestCase(unittest2.TestCase):
         conf = x.load_hadoop_xml_defaults(
             'tests/unit/resources/test-default.xml')
         self.assertEquals(x.create_hadoop_xml({'name1': 'some_val1',
-                                               'name2': 'some_val2'}, conf),
+                                               'name2': 2}, conf),
                           """<?xml version="1.0" ?>
 <?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
 <configuration>
   <property>
     <name>name2</name>
-    <value>some_val2</value>
+    <value>2</value>
   </property>
   <property>
     <name>name1</name>
diff --git a/savanna/utils/xmlutils.py b/savanna/utils/xmlutils.py
index 2a657b28..97a528ec 100644
--- a/savanna/utils/xmlutils.py
+++ b/savanna/utils/xmlutils.py
@@ -72,7 +72,7 @@ def create_hadoop_xml(configs, global_conf):
             xml_prop.appendChild(name_element)
 
             # Give the <name> element some hadoop config name
-            name_text = doc.createTextNode(name)
+            name_text = doc.createTextNode(str(name))
             name_element.appendChild(name_text)
 
             # Create a <value> element in <property>
@@ -80,7 +80,7 @@ def create_hadoop_xml(configs, global_conf):
             xml_prop.appendChild(value_element)
 
             # Give the <value> element some hadoop config value
-            value_text = doc.createTextNode(value)
+            value_text = doc.createTextNode(str(value))
             value_element.appendChild(value_text)
 
     # Return newly created XML