diff --git a/functional/test_aws_stack.py b/functional/test_aws_stack.py
index 9649a02..13c4278 100644
--- a/functional/test_aws_stack.py
+++ b/functional/test_aws_stack.py
@@ -115,7 +115,7 @@
     def test_nested_stack_create_with_timeout(self):
         url = self.publish_template(self.nested_template)
         self.template = self.test_template.replace('the.yaml', url)
-        timeout_template = yaml.load(self.template)
+        timeout_template = yaml.safe_load(self.template)
         props = timeout_template['Resources']['the_nested']['Properties']
         props['TimeoutInMinutes'] = '50'
 
@@ -142,7 +142,7 @@
                 }
             },
             "environment": {"parameters": {}},
-            "template": yaml.load(self.template)
+            "template": yaml.safe_load(self.template)
         }
 
         stack_identifier = self.stack_adopt(adopt_data=json.dumps(adopt_data))
@@ -163,7 +163,7 @@
                 }
             },
             "environment": {"parameters": {}},
-            "template": yaml.load(self.template)
+            "template": yaml.safe_load(self.template)
         }
 
         stack_identifier = self.stack_adopt(adopt_data=json.dumps(adopt_data),
@@ -180,7 +180,7 @@
         stack = self.client.stacks.get(stack_identifier)
         self.assertEqual('bar', self._stack_output(stack, 'output_foo'))
 
-        new_template = yaml.load(self.template)
+        new_template = yaml.safe_load(self.template)
         props = new_template['Resources']['the_nested']['Properties']
         props['TemplateURL'] = self.publish_template(self.update_template,
                                                      cleanup=False)
diff --git a/functional/test_default_parameters.py b/functional/test_default_parameters.py
index 3e00c35..a33823f 100644
--- a/functional/test_default_parameters.py
+++ b/functional/test_default_parameters.py
@@ -75,7 +75,7 @@
 
         if not self.temp_def:
             # remove the default from the parameter in the nested template.
-            ntempl = yaml.load(self.nested_template)
+            ntempl = yaml.safe_load(self.nested_template)
             del ntempl['parameters']['length']['default']
             nested_template = yaml.dump(ntempl)
         else:
diff --git a/functional/test_nova_server_networks.py b/functional/test_nova_server_networks.py
index 99311d0..ae550b2 100644
--- a/functional/test_nova_server_networks.py
+++ b/functional/test_nova_server_networks.py
@@ -64,3 +64,25 @@
             parameters=parms)
         networks = self.get_outputs(stack_identifier, 'networks')
         self.assertEqual(['11.11.11.11'], networks['my_net'])
+
+    def test_create_update_server_with_subnet(self):
+        parms = {'flavor': self.conf.minimal_instance_type,
+                 'image': self.conf.minimal_image_ref}
+        template = server_with_sub_fixed_ip_template.replace(
+            'fixed_ip: 11.11.11.11', 'fixed_ip: 11.11.11.22')
+        stack_identifier = self.stack_create(
+            template=template,
+            stack_name='create_server_with_sub_ip',
+            parameters=parms)
+        networks = self.get_outputs(stack_identifier, 'networks')
+        self.assertEqual(['11.11.11.22'], networks['my_net'])
+
+        # update the server only with subnet, we won't pass
+        # both port_id and net_id to attach interface, then update success
+        template_only_subnet = template.replace(
+            'fixed_ip: 11.11.11.22', '')
+        self.update_stack(stack_identifier,
+                          template_only_subnet,
+                          parameters=parms)
+        new_networks = self.get_outputs(stack_identifier, 'networks')
+        self.assertNotEqual(['11.11.11.22'], new_networks['my_net'])
diff --git a/functional/test_resource_group.py b/functional/test_resource_group.py
index e40376c..1e9edd5 100644
--- a/functional/test_resource_group.py
+++ b/functional/test_resource_group.py
@@ -419,7 +419,7 @@
         super(ResourceGroupAdoptTest, self).setUp()
 
     def _yaml_to_json(self, yaml_templ):
-        return yaml.load(yaml_templ)
+        return yaml.safe_load(yaml_templ)
 
     def test_adopt(self):
         data = {
@@ -455,7 +455,7 @@
                 }
             },
             "environment": {"parameters": {}},
-            "template": yaml.load(self.main_template)
+            "template": yaml.safe_load(self.main_template)
         }
         stack_identifier = self.stack_adopt(
             adopt_data=json.dumps(data))
@@ -556,7 +556,7 @@
         Simple rolling update with no conflict in batch size
         and minimum instances in service.
         """
-        updt_template = yaml.load(copy.deepcopy(self.template))
+        updt_template = yaml.safe_load(copy.deepcopy(self.template))
         grp = updt_template['resources']['random_group']
         policy = grp['update_policy']['rolling_update']
         policy['min_in_service'] = '1'
@@ -575,7 +575,7 @@
         Simple rolling update replace with no conflict in batch size
         and minimum instances in service.
         """
-        updt_template = yaml.load(copy.deepcopy(self.template))
+        updt_template = yaml.safe_load(copy.deepcopy(self.template))
         grp = updt_template['resources']['random_group']
         policy = grp['update_policy']['rolling_update']
         policy['min_in_service'] = '1'
@@ -594,7 +594,7 @@
 
         Simple rolling update with reduced size.
         """
-        updt_template = yaml.load(copy.deepcopy(self.template))
+        updt_template = yaml.safe_load(copy.deepcopy(self.template))
         grp = updt_template['resources']['random_group']
         policy = grp['update_policy']['rolling_update']
         policy['min_in_service'] = '1'
@@ -613,7 +613,7 @@
 
         Simple rolling update with increased size.
         """
-        updt_template = yaml.load(copy.deepcopy(self.template))
+        updt_template = yaml.safe_load(copy.deepcopy(self.template))
         grp = updt_template['resources']['random_group']
         policy = grp['update_policy']['rolling_update']
         policy['min_in_service'] = '1'
@@ -632,7 +632,7 @@
 
         Update  with capacity adjustment with enough resources.
         """
-        updt_template = yaml.load(copy.deepcopy(self.template))
+        updt_template = yaml.safe_load(copy.deepcopy(self.template))
         grp = updt_template['resources']['random_group']
         policy = grp['update_policy']['rolling_update']
         policy['min_in_service'] = '8'
@@ -652,7 +652,7 @@
         Rolling update with capacity adjustment due to conflict in
         batch size and minimum instances in service.
         """
-        updt_template = yaml.load(copy.deepcopy(self.template))
+        updt_template = yaml.safe_load(copy.deepcopy(self.template))
         grp = updt_template['resources']['random_group']
         policy = grp['update_policy']['rolling_update']
         policy['min_in_service'] = '8'
@@ -671,7 +671,7 @@
         Rolling Update with a huge batch size(more than
         current size).
         """
-        updt_template = yaml.load(copy.deepcopy(self.template))
+        updt_template = yaml.safe_load(copy.deepcopy(self.template))
         grp = updt_template['resources']['random_group']
         policy = grp['update_policy']['rolling_update']
         policy['min_in_service'] = '0'
@@ -689,7 +689,7 @@
         Rolling Update with a huge number of minimum instances
         in service.
         """
-        updt_template = yaml.load(copy.deepcopy(self.template))
+        updt_template = yaml.safe_load(copy.deepcopy(self.template))
         grp = updt_template['resources']['random_group']
         policy = grp['update_policy']['rolling_update']
         policy['min_in_service'] = '20'
diff --git a/functional/test_template_resource.py b/functional/test_template_resource.py
index 9249a6e..fa34e2e 100644
--- a/functional/test_template_resource.py
+++ b/functional/test_template_resource.py
@@ -602,7 +602,7 @@
         super(TemplateResourceAdoptTest, self).setUp()
 
     def _yaml_to_json(self, yaml_templ):
-        return yaml.load(yaml_templ)
+        return yaml.safe_load(yaml_templ)
 
     def test_abandon(self):
         stack_identifier = self.stack_create(
@@ -635,7 +635,7 @@
                 }
             },
             "environment": {"parameters": {}},
-            "template": yaml.load(self.main_template)
+            "template": yaml.safe_load(self.main_template)
         }
 
         stack_identifier = self.stack_adopt(
diff --git a/scenario/test_autoscaling_lb.py b/scenario/test_autoscaling_lb.py
index 080f17f..e3de091 100644
--- a/scenario/test_autoscaling_lb.py
+++ b/scenario/test_autoscaling_lb.py
@@ -38,7 +38,11 @@
         resp = set()
         for count in range(retries):
             time.sleep(1)
-            r = requests.get(url)
+            try:
+                r = requests.get(url)
+            except requests.exceptions.ConnectionError:
+                # The LB may not be up yet, let's retry
+                continue
             # skip unsuccessful requests
             if r.status_code == 200:
                 resp.add(r.text)