=== modified file 'cloudinit/sources/DataSourceAzure.py'
--- cloudinit/sources/DataSourceAzure.py	2014-01-09 18:12:40 +0000
+++ cloudinit/sources/DataSourceAzure.py	2014-02-07 11:51:56 +0000
@@ -84,9 +84,14 @@
 
         candidates = [self.seed_dir]
         candidates.extend(list_possible_azure_ds_devs())
+        previous_ovf_cfg = None
         if ddir:
             candidates.append(ddir)
 
+        previous_ovf_cfg = None
+        if os.path.exists("%s/ovf-env.xml" % ddir):
+            previous_ovf_cfg = load_azure_ds_dir(ddir)
+
         found = None
 
         for cdev in candidates:
@@ -104,6 +109,11 @@
                 LOG.warn("%s was not mountable" % cdev)
                 continue
 
+            if ret != previous_ovf_cfg:
+                LOG.info(("instance configuration has changed, "
+                          "removing old agent directory"))
+                util.del_dir(ddir)
+
             (md, self.userdata_raw, cfg, files) = ret
             self.seed = cdev
             self.metadata = util.mergemanydict([md, DEFAULT_METADATA])

=== modified file 'tests/unittests/test_datasource/test_azure.py'
--- tests/unittests/test_datasource/test_azure.py	2013-10-02 21:05:15 +0000
+++ tests/unittests/test_datasource/test_azure.py	2014-02-07 11:51:56 +0000
@@ -119,6 +119,10 @@
                          {'ovf-env.xml': data['ovfcontent']})
 
         mod = DataSourceAzure
+        ddir = "%s/var/lib/waagent" % self.tmp
+        mod.BUILTIN_DS_CONFIG['data_dir'] = ddir
+        if not os.path.isdir(ddir):
+            os.makedirs(ddir)
 
         self.apply_patches([(mod, 'list_possible_azure_ds_devs', dsdevs)])
 
@@ -338,6 +342,40 @@
 
         self.assertEqual(userdata, dsrc.userdata_raw)
 
+    def test_existing_ovf_same(self):
+        mydata = "FOOBAR"
+        odata = {'UserData': base64.b64encode(mydata)}
+        data = {'ovfcontent': construct_valid_ovf_env(data=odata)}
+
+        with open("%s/ovf-env.xml" % self.tmp, 'w') as fp:
+            fp.write(construct_valid_ovf_env(data=odata))
+        with open("%s/sem" % self.tmp, 'w') as fp:
+            fp.write("test")
+
+        dsrc = self._get_ds(data)
+        ret = dsrc.get_data()
+        self.assertTrue(ret)
+        self.assertEqual(dsrc.userdata_raw, mydata)
+        self.assertTrue(os.path.exists("%s/sem" % self.tmp))
+
+    def test_existing_ovf_diff(self):
+        mydata = "FOOBAR"
+        odata = {'UserData': base64.b64encode(mydata)}
+        data = {'ovfcontent': construct_valid_ovf_env(data=odata)}
+
+        data_dir = "%s/var/lib/waagent" % self.tmp
+        os.makedirs(data_dir)
+        with open("%s/ovf-env.xml" % data_dir, 'w') as fp:
+            fp.write(construct_valid_ovf_env())
+        with open("%s/sem" % data_dir, 'w') as fp:
+            fp.write("test")
+
+        dsrc = self._get_ds(data)
+        ret = dsrc.get_data()
+        self.assertTrue(ret)
+        self.assertEqual(dsrc.userdata_raw, mydata)
+        self.assertFalse(os.path.exists("%s/sem" % data_dir))
+
 
 class TestReadAzureOvf(MockerTestCase):
     def test_invalid_xml_raises_non_azure_ds(self):